<HTML>
<HEAD>
     <TITLE></TITLE>
</HEAD>
<BODY STYLE="font: 10pt Times New Roman, Times, Serif">

<P STYLE="margin: 0">&nbsp;</P>

<P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0pt 0pt 3pt; text-align: center"><B>As filed with the Securities and Exchange Commission
on March 20, 2024</B>&nbsp;</P>

<P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0pt 0pt 3pt; text-align: right"><B>Registration No. 333-</B></P>

<!-- Field: Rule-Page --><DIV STYLE="margin-top: 1pt; margin-bottom: 1pt; width: 100%"><DIV STYLE="font-size: 1pt; border-top: Black 3.5pt solid; border-bottom: Black 1pt solid">&nbsp;</DIV></DIV><!-- Field: /Rule-Page -->

<P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0pt 0; text-align: center"><B>&nbsp;</B></P>

<P STYLE="font: 14pt Times New Roman, Times, Serif; margin: 0pt 0; text-align: center"><B>UNITED STATES</B></P>

<P STYLE="font: 14pt Times New Roman, Times, Serif; margin: 0pt 0; text-align: center"><B>SECURITIES AND EXCHANGE COMMISSION</B></P>

<P STYLE="font: 12pt Times New Roman, Times, Serif; margin: 0pt 0; text-align: center"><B>Washington, D.C. 20549</B></P>

<!-- Field: Rule-Page --><DIV STYLE="margin: 3pt auto; width: 25%"><DIV STYLE="font-size: 1pt; border-top: Black 1pt solid">&nbsp;</DIV></DIV><!-- Field: /Rule-Page -->

<P STYLE="font: 12pt Times New Roman, Times, Serif; margin: 0pt 0; text-align: center"><B></B></P>



<P STYLE="font: 14pt Times New Roman, Times, Serif; margin: 0pt 0; text-align: center"><B>FORM S-8</B></P>



<P STYLE="font: 14pt Times New Roman, Times, Serif; margin: 0pt 0; text-align: center"><B></B></P>

<P STYLE="font: 12pt Times New Roman, Times, Serif; margin: 0pt 0; text-align: center"><B>REGISTRATION STATEMENT UNDER</B></P>

<P STYLE="font: 12pt Times New Roman, Times, Serif; margin: 0pt 0; text-align: center"><B>THE SECURITIES ACT OF 1933</B></P>

<!-- Field: Rule-Page --><DIV STYLE="margin: 3pt auto; width: 25%"><DIV STYLE="font-size: 1pt; border-top: Black 1pt solid">&nbsp;</DIV></DIV><!-- Field: /Rule-Page -->

<P STYLE="font: 12pt Times New Roman, Times, Serif; margin: 0pt 0; text-align: center"><B></B></P>



<P STYLE="font: 14pt Times New Roman, Times, Serif; margin: 0pt 0; text-align: center"><B>ULTRA CLEAN HOLDINGS, INC.</B></P>

<P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0pt 0; text-align: center">(Exact Name of Registrant as Specified in its Charter)</P>

<P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0pt 0; text-align: center">&nbsp;</P>

<TABLE CELLSPACING="2" CELLPADDING="2" STYLE="font: 10pt Times New Roman, Times, Serif; width: 100%; border-collapse: collapse">
  <TR STYLE="vertical-align: bottom">
    <TD STYLE="width: 29%; text-align: center"><FONT STYLE="font-size: 10pt"><B>Delaware</B></FONT></TD>
    <TD STYLE="width: 44%; text-align: center">&nbsp;</TD>
    <TD STYLE="width: 27%; text-align: center"><FONT STYLE="font-size: 10pt"><B>61-1430858</B></FONT></TD></TR>
  <TR STYLE="vertical-align: top">
    <TD STYLE="text-align: center"><FONT STYLE="font-size: 10pt">(State or Other Jurisdiction of <BR>
Incorporation or Organization)</FONT></TD>
    <TD STYLE="text-align: center">&nbsp;</TD>
    <TD STYLE="text-align: center"><FONT STYLE="font-size: 10pt">(I.R.S. Employer <BR>
Identification No.)</FONT></TD></TR>
  <TR STYLE="vertical-align: top">
    <TD STYLE="text-align: center">&nbsp;</TD>
    <TD>
    <P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0pt 0; text-align: center"><B>26462 CORPORATE AVENUE</B></P>
    <P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0pt 0; text-align: center"><B>HAYWARD, CA 94545</B></P></TD>
    <TD STYLE="text-align: center">&nbsp;</TD></TR>
  <TR STYLE="vertical-align: top">
    <TD COLSPAN="3" STYLE="text-align: center"><FONT STYLE="font-size: 10pt">(Address of Principal Executive Offices)</FONT></TD></TR>
  </TABLE>

<P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0pt 0; text-align: center">&nbsp;</P>

<P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0pt 0; text-align: center"><P STYLE="margin: 0"></P>

<!-- Field: Rule-Page --><DIV STYLE="margin: 3pt auto; width: 25%"><DIV STYLE="border-top: Black 1pt solid; font-size: 1pt">&nbsp;</DIV></DIV><!-- Field: /Rule-Page -->

<P STYLE="margin: 0"></P>


<P STYLE="margin: 0">&nbsp;</P>
</P>

<P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0pt 0; text-align: center"><B></B></P>

<P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0pt 0; text-align: center"><B>Ultra Clean Holdings, Inc. Amended and Restated
Stock Incentive Plan<BR>
Ultra Clean Holdings, Inc. Amended and Restated Employee Stock Purchase Plan</B></P>

<P STYLE="text-align: center; margin-top: 0pt; font: 10pt Times New Roman, Times, Serif; margin-bottom: 0pt">(Full Titles of the Plans)</P>

<P STYLE="margin: 0">&nbsp;</P>

<P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0pt 0; text-align: center; background-color: white"><B>James P. Scholhamer</B></P>

<P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0pt 0; text-align: center; background-color: white"><B>Chief Executive Officer</B></P>

<P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0pt 0; text-align: center; background-color: white"><B>Ultra Clean Holdings,
Inc.</B></P>

<P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0pt 0; text-align: center; background-color: white"><B>26462 Corporate Avenue</B></P>

<P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0pt 0; text-align: center; background-color: white"><B>Hayward, CA 94545</B></P>

<P STYLE="text-align: center; margin-top: 0pt; font: 10pt Times New Roman, Times, Serif; margin-bottom: 0pt"><B>(510) 576-4600 (Name,
Address, Including Zip Code, and</B></P>

<P STYLE="font: 10pt Times New Roman, Times, Serif; text-align: center; margin-top: 0pt; margin-bottom: 0pt"><B>Telephone Number, Including Area Code, of Agent For Service</B></P>

<P STYLE="margin: 0pt 0; font: 10pt Times New Roman, Times, Serif">&nbsp;</P>

<P STYLE="margin: 0"></P>

<!-- Field: Rule-Page --><DIV STYLE="margin: 3pt auto; width: 25%"><DIV STYLE="border-top: Black 1pt solid; font-size: 1pt">&nbsp;</DIV></DIV><!-- Field: /Rule-Page -->

<P STYLE="margin: 0"></P>


<P STYLE="margin: 0">&nbsp;</P>


<P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0pt 0pt 3pt; text-align: center"><I>With copies to:</I></P>

<P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0pt 0; text-align: center">Alan F. Denenberg, Esq.<BR>
Davis Polk &amp; Wardwell LLP<BR>
1600 El Camino Real</P>

<P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0pt 0; text-align: center">Menlo Park, California 94025<BR>
(650) 752-2000</P>

<P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0pt 0; text-align: center">&nbsp;</P>




<P STYLE="margin: 0"></P>



<P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0pt 0"></P>

<!-- Field: Rule-Page --><DIV STYLE="margin: 3pt auto; width: 25%"><DIV STYLE="font-size: 1pt; border-top: Black 1pt solid">&nbsp;</DIV></DIV><!-- Field: /Rule-Page -->

<P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 3pt 0pt"><B>Indicate by check mark whether the registrant is a large accelerated
filer, an accelerated filer, a non-accelerated filer, a smaller reporting company or an emerging growth company. See the definitions
of &ldquo;large accelerated filer,&rdquo; &ldquo;accelerated filer, &rdquo; &ldquo;smaller reporting company&rdquo; and &ldquo;emerging
growth company&rdquo; in Rule 12b-2 of the Exchange Act. </B></P>

<TABLE CELLSPACING="2" CELLPADDING="2" STYLE="font: 10pt Times New Roman, Times, Serif; width: 100%; border-collapse: collapse">
  <TR STYLE="vertical-align: top">
    <TD STYLE="width: 62%"><FONT STYLE="font-size: 10pt"><B>Large accelerated filer </B></FONT><FONT STYLE="font-size: 14pt">&#9746;</FONT></TD>
    <TD STYLE="width: 38%"><FONT STYLE="font-size: 10pt"><B>Accelerated filer </B></FONT><FONT STYLE="font-size: 14pt">&#9744;</FONT></TD></TR>
  <TR STYLE="vertical-align: top">
    <TD><FONT STYLE="font-size: 10pt"><B>Non-accelerated filer </B></FONT><FONT STYLE="font-size: 14pt">&#9744;</FONT><FONT STYLE="font-size: 10pt"><B>&nbsp;(Do
    not check if a smaller reporting company)</B></FONT></TD>
    <TD><FONT STYLE="font-size: 10pt"><B>Smaller reporting company </B></FONT><FONT STYLE="font-size: 14pt">&#9744;</FONT></TD></TR>
  <TR STYLE="vertical-align: top">
    <TD>&nbsp;</TD>
    <TD><FONT STYLE="font-size: 10pt"><B>Emerging Growth Company </B></FONT><FONT STYLE="font-size: 14pt">&#9744;</FONT></TD></TR>
  </TABLE>

<P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0pt 0"></P>

<P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 3pt 0pt 0pt"><FONT STYLE="font-size: 10pt">If an emerging growth company, indicate
by check mark if the registrant has elected not to use the extended transition period for complying with any new or revised financial
accounting standards provided pursuant to Section 7(a)(2)(B) of the Securities Act. </FONT><FONT STYLE="font-size: 14pt">&#9744;</FONT></P>

<P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0pt 0">&nbsp;</P>


<!-- Field: Page; Sequence: 1 -->
    <DIV STYLE="margin-bottom: 6pt; border-bottom: Black 1pt solid"><TABLE CELLPADDING="0" CELLSPACING="0" STYLE="width: 100%"><TR><TD STYLE="text-align: center; width: 100%">&nbsp;</TD></TR></TABLE></DIV>
    <DIV STYLE="break-before: page; margin-top: 6pt"><TABLE CELLPADDING="0" CELLSPACING="0" STYLE="width: 100%"><TR><TD STYLE="text-align: center; width: 100%">&nbsp;</TD></TR></TABLE></DIV>
    <!-- Field: /Page -->

<P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0pt 0; text-align: center"><B>EXPLANATORY NOTE</B></P>

<P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0pt 0; text-align: center">&nbsp;</P>

<P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0pt 0; text-indent: 0.25in">Pursuant to General Instruction E to Form S-8,
Ultra Clean Holdings, Inc. (the &ldquo;Registrant&rdquo;) is filing this Registration Statement on Form S-8 (this &ldquo;Registration
Statement&rdquo;) with the U.S. Securities and Exchange Commission (the &ldquo;Commission&rdquo;) to register additional 2,000,000 shares
of common stock of the Registrant for issuance under the Registrant&rsquo;s Amended and Restated Stock Incentive Plan (the &ldquo;Stock
Plan&rdquo;) and 500,000 shares of common stock of the Registrant for issuance under the Registrant&rsquo;s Employee Stock Purchase Plan
(&ldquo;ESPP&rdquo;). These additional shares of common stock are securities of the same class and relate to the same employee benefit
plan (as amended from time to time) as other securities for which a registration statement on Form S-8 has been filed with the Securities
and Exchange Commission on March 30, 2004 (File No. <A HREF="https://www.sec.gov/Archives/edgar/data/1275014/000095010304000461/mar2904_s8.htm" STYLE="color: Blue; text-decoration: underline">333-114051</A>),
April 4, 2005 (File No. <A HREF="https://www.sec.gov/Archives/edgar/data/1275014/000095010305001178/apr0105_s8.htm" STYLE="color: Blue; text-decoration: underline">333-123820</A>), June
19, 2006 (File No. <A HREF="https://www.sec.gov/Archives/edgar/data/1275014/000095010306001556/dp02836_s8.htm" STYLE="color: Blue; text-decoration: underline">333-135147</A>), April
9, 2007 (File No. <A HREF="https://www.sec.gov/Archives/edgar/data/1275014/000095013407007853/f29102sv8.htm" STYLE="color: Blue; text-decoration: underline">333-141989</A>), May 30,
2008 (File No. <A HREF="https://www.sec.gov/Archives/edgar/data/1275014/000095010308001497/dp10145_s8.htm" STYLE="color: Blue; text-decoration: underline">333-151335</A>), March 19,
2009 (File No. <A HREF="https://www.sec.gov/Archives/edgar/data/1275014/000095010309000576/dp12856_s8.htm" STYLE="color: Blue; text-decoration: underline">333-158108</A>), March 30,
2010 (File No. <A HREF="https://www.sec.gov/Archives/edgar/data/1275014/000095010310000920/dp16929_s8.htm" STYLE="color: Blue; text-decoration: underline">333-165782</A>), June 15, 2010
(File No. <A HREF="https://www.sec.gov/Archives/edgar/data/1275014/000095010310001784/dp18156_s8.htm" STYLE="color: Blue; text-decoration: underline">333-167530</A>), May 31, 2013 (File
No. <A HREF="https://www.sec.gov/Archives/edgar/data/1275014/000095010313003363/dp38560_s8.htm" STYLE="color: Blue; text-decoration: underline">333-188995</A>), July 25, 2017 (File No.
<A HREF="https://www.sec.gov/ix?doc=/Archives/edgar/data/0001275014/000095010317007059/dp78584_s8.htm" STYLE="color: Blue; text-decoration: underline">333-219447</A>) and December 18,
2019 (File No. <A HREF="https://www.sec.gov/Archives/edgar/data/1275014/000095010319017347/dp117698_s8.htm" STYLE="color: Blue; text-decoration: underline">333-235574</A>), the contents
of which are hereby incorporated by reference. These additional shares of common stock have become reserved for issuance as a result of
the amendment and restatement of (i) the Registrant&rsquo;s Amended and Restated Stock Incentive Plan, effective as of May 17, 2023 and
(ii) the Registrant&rsquo;s Amended and Restated Employee Stock Purchase Plan, effective as of May 17, 2023.</P>

<P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0pt 0; text-indent: 0.25in">&nbsp;</P>


<!-- Field: Page; Sequence: 2 -->
    <DIV STYLE="margin-bottom: 6pt; border-bottom: Black 1pt solid"><TABLE CELLPADDING="0" CELLSPACING="0" STYLE="width: 100%"><TR><TD STYLE="text-align: center; width: 100%">&nbsp;</TD></TR></TABLE></DIV>
    <DIV STYLE="break-before: page; margin-top: 6pt"><TABLE CELLPADDING="0" CELLSPACING="0" STYLE="width: 100%"><TR><TD STYLE="text-align: center; width: 100%">&nbsp;</TD></TR></TABLE></DIV>
    <!-- Field: /Page -->

<P STYLE="font: bold 10pt Times New Roman, Times, Serif; margin: 0pt 0; text-align: center">PART II<BR>
INFORMATION REQUIRED IN THE REGISTRATION STATEMENT</P>

<P STYLE="font: bold 10pt Times New Roman, Times, Serif; margin: 0pt 0; text-align: center">&nbsp;</P>

<P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0pt 0"><B>Item 3. Incorporation of Documents by Reference.</B></P>

<P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0pt 0">&nbsp;</P>

<P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0pt 0; text-indent: 0.25in">The following documents filed by the Registrant
with the Commission under the Securities Act of 1933, as amended (the &ldquo;Securities Act&rdquo;) or the Securities Exchange Act of
1934, as amended (the &ldquo;Exchange Act&rdquo;), are incorporated herein by reference:</P>

<P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0pt 0; text-indent: 0.25in">&nbsp;</P>

<TABLE CELLPADDING="0" CELLSPACING="0" WIDTH="100%" STYLE="font: 10pt Times New Roman, Times, Serif; margin-top: 0pt; margin-bottom: 0pt"><TR STYLE="vertical-align: top">
<TD STYLE="width: 0.25in"></TD><TD STYLE="width: 0.25in">(a)</TD><TD>The Registrant&rsquo;s Annual Report on Form 10-K for the fiscal year ended December 29, 2023 filed with the Commission on March 6,
2024 (File No. <A HREF="https://www.sec.gov/ix?doc=/Archives/edgar/data/0001275014/000095017024027213/uctt-20231229.htm" STYLE="color: Blue; text-decoration: underline">000-50646</A>)
(the &ldquo;Annual Report);</TD></TR></TABLE>

<P STYLE="margin-top: 0pt; margin-bottom: 0pt; font: 10pt Times New Roman, Times, Serif">&nbsp;</P>

<TABLE CELLPADDING="0" CELLSPACING="0" WIDTH="100%" STYLE="font: 10pt Times New Roman, Times, Serif; margin-top: 0pt; margin-bottom: 0pt"><TR STYLE="vertical-align: top">
<TD STYLE="width: 0.25in"></TD><TD STYLE="width: 0.25in">(b)</TD><TD>All other reports filed by the Registrant pursuant to Section 13(a) or Section 15(d) of the Exchange Act, since December 29, 2023
(other than Current Reports furnished under Item 2.02 or Item 7.01 of Form 8-K and exhibits furnished on that form that relate to such
items); and</TD></TR></TABLE>

<P STYLE="margin-top: 0pt; margin-bottom: 0pt; font: 10pt Times New Roman, Times, Serif">&nbsp;</P>

<TABLE CELLPADDING="0" CELLSPACING="0" WIDTH="100%" STYLE="font: 10pt Times New Roman, Times, Serif; margin-top: 0pt; margin-bottom: 0pt"><TR STYLE="vertical-align: top">
<TD STYLE="width: 0.25in"></TD><TD STYLE="width: 0.25in">(c)</TD><TD>The description of the Registrant&rsquo;s common stock contained in <A HREF="https://www.sec.gov/Archives/edgar/data/1275014/000095017024027213/uctt-ex4_2.htm" STYLE="color: Blue; text-decoration: underline">Exhibit
4.2</A> to the Registrant&rsquo;s Annual Report, including any amendments or reports filed for the purpose of updating such description.&nbsp;</TD></TR></TABLE>

<P STYLE="margin-top: 0pt; margin-bottom: 0pt; font: 10pt Times New Roman, Times, Serif">&nbsp;</P>

<P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0pt 0; text-indent: 0.25in">In addition, all documents subsequently filed
by the Registrant pursuant to Sections 13(a), 13(c), 14 and 15(d) of the Exchange Act (other than documents or any information therein
deemed to have been furnished and not filed in accordance with rules of the Commission), prior to the filing of a post-effective amendment
to this Registration Statement, which indicates that all securities offered have been sold or which deregisters all securities then remaining
unsold, shall be deemed to be incorporated by reference in this Registration Statement and to be a part hereof from the date of the filing
of such documents.</P>

<P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0pt 0; text-indent: 0.25in">&nbsp;</P>

<P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0pt 0; text-indent: 0.25in">Any statement contained in a document incorporated
or deemed to be incorporated by reference herein shall be deemed to be modified or superseded for purposes of this Registration Statement
to the extent that a statement contained herein (or in any other subsequently filed document which also is incorporated or deemed to be
incorporated by reference herein), modifies or supersedes such statement. Any such statement so modified or superseded shall not be deemed,
except as so modified or superseded, to constitute a part of this Registration Statement.</P>

<P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0pt 0; text-indent: 0.25in">&nbsp;</P>


<!-- Field: Page; Sequence: 3 -->
    <DIV STYLE="margin-bottom: 6pt; border-bottom: Black 1pt solid"><TABLE CELLPADDING="0" CELLSPACING="0" STYLE="width: 100%"><TR><TD STYLE="text-align: center; width: 100%">&nbsp;</TD></TR></TABLE></DIV>
    <DIV STYLE="break-before: page; margin-top: 6pt"><TABLE CELLPADDING="0" CELLSPACING="0" STYLE="width: 100%"><TR><TD STYLE="text-align: center; width: 100%">&nbsp;</TD></TR></TABLE></DIV>
    <!-- Field: /Page -->

<P STYLE="font: bold 10pt Times New Roman, Times, Serif; margin: 0pt 0">Item 8. Exhibits.</P>

<P STYLE="font: bold 10pt Times New Roman, Times, Serif; margin: 0pt 0">&nbsp;</P>

<TABLE CELLSPACING="2" CELLPADDING="2" STYLE="font: 10pt Times New Roman, Times, Serif; width: 100%; border-collapse: collapse">
  <TR STYLE="vertical-align: top">
    <TD STYLE="width: 10%">
    <P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0pt 0; border-bottom: Black 0.5pt solid">Exhibit Number</P></TD>
    <TD STYLE="width: 90%; font-size: 11pt">&nbsp;</TD></TR>
  <TR STYLE="vertical-align: top">
    <TD STYLE="font-size: 11pt"><FONT STYLE="font-size: 10pt">4.1</FONT></TD>
    <TD STYLE="font-size: 11pt"><FONT STYLE="font-size: 10pt">Form of Amended and Restated Certificate of Incorporation (incorporated by reference to Exhibit <A HREF="https://www.sec.gov/Archives/edgar/data/1275014/000089161804000663/f95546a2exv3w1.txt">3.1</A> of the Registrant&rsquo;s Annual Report) </FONT></TD></TR>
  <TR STYLE="vertical-align: top">
    <TD STYLE="font-size: 11pt"><A HREF="dp208624_ex0501-2302.htm" STYLE="color: Blue; text-decoration: underline"><FONT STYLE="font-size: 10pt">5.1*</FONT></A></TD>
    <TD STYLE="font-size: 11pt"><A HREF="dp208624_ex0501-2302.htm" STYLE="color: Blue; text-decoration: underline"><FONT STYLE="font-size: 10pt">Opinion of Davis Polk &amp; Wardwell LLP</FONT></A></TD></TR>
  <TR STYLE="vertical-align: top">
    <TD STYLE="font-size: 11pt"><A HREF="dp208624_ex2301.htm" STYLE="color: Blue; text-decoration: underline"><FONT STYLE="font-size: 10pt">23.1*</FONT></A></TD>
    <TD STYLE="font-size: 11pt"><A HREF="dp208624_ex2301.htm" STYLE="color: Blue; text-decoration: underline"><FONT STYLE="font-size: 10pt">Consent of Moss Adams LLP, independent registered public accounting firm</FONT></A></TD></TR>
  <TR STYLE="vertical-align: top">
    <TD STYLE="font-size: 11pt"><A HREF="dp208624_ex0501-2302.htm" STYLE="color: Blue; text-decoration: underline"><FONT STYLE="font-size: 10pt">23.2*</FONT></A></TD>
    <TD STYLE="font-size: 11pt"><A HREF="dp208624_ex0501-2302.htm" STYLE="color: Blue; text-decoration: underline"><FONT STYLE="font-size: 10pt">Consent of Davis Polk &amp; Wardwell LLP (included in Exhibit 5.1)</FONT></A></TD></TR>
  <TR STYLE="vertical-align: top">
    <TD STYLE="font-size: 11pt"><A HREF="#a_001" STYLE="color: Blue; text-decoration: underline"><FONT STYLE="font-size: 10pt">24.1*</FONT></A></TD>
    <TD STYLE="font-size: 11pt"><A HREF="#a_001" STYLE="color: Blue; text-decoration: underline"><FONT STYLE="font-size: 10pt">Powers of Attorney (included on signature page)</FONT></A></TD></TR>
  <TR STYLE="vertical-align: top">
    <TD STYLE="font-size: 11pt"><FONT STYLE="font-size: 10pt">99.1</FONT></TD>
    <TD STYLE="font-size: 11pt"><FONT STYLE="font-size: 10pt">Ultra Clean Holdings, Inc. Amended and Restated Stock Incentive Plan (incorporated by reference to Exhibit <A HREF="https://www.sec.gov/Archives/edgar/data/1275014/000095017024027213/uctt-ex10_1.htm" STYLE="color: Blue; text-decoration: underline">10.1</A> of the Registrant&rsquo;s Annual Report)</FONT></TD></TR>
  <TR STYLE="vertical-align: top">
    <TD STYLE="font-size: 11pt"><FONT STYLE="font-size: 10pt">99.2</FONT></TD>
    <TD STYLE="font-size: 11pt"><FONT STYLE="font-size: 10pt">Ultra Clean Holdings, Inc. Employee Stock Purchase Plan (incorporated by reference to Exhibit <A HREF="https://www.sec.gov/Archives/edgar/data/1275014/000095017024027213/uctt-ex10_5.htm" STYLE="color: Blue; text-decoration: underline">10.5</A> of the Registrant&rsquo;s Annual Report)</FONT></TD></TR>
  <TR STYLE="vertical-align: top">
    <TD STYLE="font-size: 11pt"><A HREF="dp208624_exfilingfees.htm" STYLE="color: Blue; text-decoration: underline"><FONT STYLE="font-size: 10pt">107*</FONT></A></TD>
    <TD STYLE="font-size: 11pt"><A HREF="dp208624_exfilingfees.htm" STYLE="color: Blue; text-decoration: underline"><FONT STYLE="font-size: 10pt">Filing Fee Table</FONT></A></TD></TR>
  </TABLE>
<P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0pt 0"></P>

<P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0pt 0"></P>

<!-- Field: Rule-Page --><DIV STYLE="margin-top: 3pt; margin-bottom: 3pt; width: 25%"><DIV STYLE="font-size: 1pt; border-top: Black 1pt solid">&nbsp;</DIV></DIV><!-- Field: /Rule-Page -->

<P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0pt 0"><FONT STYLE="font-size: 9pt; font-weight: normal">*&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;Filed
herewith.</FONT></P>

<P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0pt 0">&nbsp;</P>


<!-- Field: Page; Sequence: 4 -->
    <DIV STYLE="margin-bottom: 6pt; border-bottom: Black 1pt solid"><TABLE CELLPADDING="0" CELLSPACING="0" STYLE="width: 100%"><TR><TD STYLE="text-align: center; width: 100%">&nbsp;</TD></TR></TABLE></DIV>
    <DIV STYLE="break-before: page; margin-top: 6pt"><TABLE CELLPADDING="0" CELLSPACING="0" STYLE="width: 100%"><TR><TD STYLE="text-align: center; width: 100%">&nbsp;</TD></TR></TABLE></DIV>
    <!-- Field: /Page -->

<P STYLE="font: bold 10pt Times New Roman, Times, Serif; margin: 0pt 0; text-align: center">SIGNATURES</P>

<P STYLE="font: bold 10pt Times New Roman, Times, Serif; margin: 0pt 0; text-align: center">&nbsp;</P>

<P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0pt 0; text-indent: 0.25in">Pursuant to the requirements of the Securities
Act, the Registrant, Ultra Clean Holdings, Inc., certifies that it has reasonable grounds to believe that it meets all of the requirements
for filing on Form S-8 and has duly caused this Registration Statement to be signed on its behalf by the undersigned, thereunto duly authorized,
in the City of Hayward, State of California, on the 20<SUP>th</SUP> day of March, 2024.</P>

<P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0pt 0; text-indent: 0.25in">&nbsp;</P>

<TABLE CELLSPACING="2" CELLPADDING="2" STYLE="font: 10pt Times New Roman, Times, Serif; width: 100%; border-collapse: collapse">
  <TR STYLE="vertical-align: top">
    <TD>&nbsp;</TD>
    <TD COLSPAN="3">
    <P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0pt 0"><B>ULTRA CLEAN HOLDINGS, INC.</B></P></TD></TR>
  <TR STYLE="vertical-align: top">
    <TD>&nbsp;</TD>
    <TD COLSPAN="3">&nbsp;</TD></TR>
  <TR STYLE="vertical-align: top">
    <TD>&nbsp;</TD>
    <TD STYLE="font-size: 10pt">By:</TD>
    <TD COLSPAN="2" STYLE="border-bottom: Black 1pt solid; font-size: 10pt">/s/ James P. Scholhamer</TD></TR>
  <TR STYLE="vertical-align: top">
    <TD STYLE="width: 60%">&nbsp;</TD>
    <TD STYLE="width: 3%; font-size: 10pt">&nbsp;</TD>
    <TD STYLE="width: 7%; font-size: 10pt">Name:</TD>
    <TD STYLE="width: 30%; font-size: 10pt">James P. Scholhamer</TD></TR>
  <TR STYLE="vertical-align: top">
    <TD>&nbsp;</TD>
    <TD STYLE="font-size: 10pt">&nbsp;</TD>
    <TD STYLE="font-size: 10pt">Title:</TD>
    <TD STYLE="padding-left: 3.65pt; font-size: 10pt; text-indent: -3.65pt">Chief Executive Officer</TD></TR>
</TABLE>

<P STYLE="margin: 0">&nbsp;</P>


<!-- Field: Page; Sequence: 5 -->
    <DIV STYLE="margin-bottom: 6pt; border-bottom: Black 1pt solid"><P STYLE="margin: 0pt">&nbsp;</P></DIV>
    <DIV STYLE="break-before: page; margin-top: 6pt"><P STYLE="margin: 0pt">&nbsp;</P></DIV>
    <!-- Field: /Page -->

<P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0pt 0; text-align: center; text-indent: 0.25in"><A NAME="a_001" TITLE="POA"></A><B>POWER OF ATTORNEY AND SIGNATURES</B></P>

<P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0pt 0; text-align: center; text-indent: 0.25in">&nbsp;</P>

<P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0pt 0; text-indent: 0.25in">Know all persons by these presents, that each
person whose signature appears below constitutes and appoints James P. Scholhamer and Sheri Savage and each of them, as his or her true
and lawful attorney-in-fact and agents, upon the action of such appointee, with full power of substitution and resubstitution, to do any
and all acts and things and execute, in the name of the undersigned, any and all instruments which each of said attorneys-in-fact and
agents may deem necessary or advisable in order to enable Ultra Clean Holdings, Inc, to comply with the Securities Act, and any requirements
of the Commission in respect thereof, in connection with the filing with the Commission of this Registration Statement under the Securities
Act, including specifically but without limitation, power and authority to sign the name of the undersigned to such Registration Statement,
and any amendments to such Registration Statement (including post-effective amendments), and to file the same with all exhibits thereto
and other documents in connection therewith, with the Commission, to sign any and all applications, registration statements, notices or
other documents necessary or advisable to comply with applicable state securities laws, and to file the same, together with other documents
in connection therewith with the appropriate state securities authorities, granting unto each of said attorneys-in-fact and agents full
power and authority to do and to perform each and every act and thing requisite or necessary to be done in and about the premises, as
fully and to all intents and purposes as the undersigned might or could do in person, hereby ratifying and confirming all that each of
said attorneys-in-fact and agents may lawfully do or cause to be done by virtue hereof.</P>

<P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0pt 0; text-indent: 0.25in">&nbsp;</P>

<P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0pt 0; text-indent: 20.15pt">Pursuant to the requirements of the Securities
Act, this Registration Statement has been signed by the following persons in the capacities and on the dates indicated:</P>

<P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0pt 0; text-indent: 20.15pt">&nbsp;</P>

<TABLE CELLSPACING="2" CELLPADDING="2" STYLE="font: 10pt Times New Roman, Times, Serif; width: 100%; border-collapse: collapse">
  <TR STYLE="vertical-align: bottom">
    <TD STYLE="white-space: nowrap; width: 42%">
    <P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0pt 0; text-align: center"><B>Signature</B></P>
<!-- Field: Rule-Page --><DIV STYLE="margin-top: 1pt; margin-bottom: 1pt; width: 100%"><DIV STYLE="font-size: 1pt; border-top: Black 1pt solid">&nbsp;</DIV></DIV><!-- Field: /Rule-Page --></TD>
    <TD STYLE="white-space: nowrap; width: 38%">
    <P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0pt 0; text-align: center"><B>Title</B></P>
<!-- Field: Rule-Page --><DIV STYLE="margin-top: 1pt; margin-bottom: 1pt; width: 100%"><DIV STYLE="font-size: 1pt; border-top: Black 1pt solid">&nbsp;</DIV></DIV><!-- Field: /Rule-Page --></TD>
    <TD STYLE="white-space: nowrap; width: 20%">
    <P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0pt 0; text-align: center"><B>Date</B></P>
<!-- Field: Rule-Page --><DIV STYLE="margin-top: 1pt; margin-bottom: 1pt; width: 100%"><DIV STYLE="font-size: 1pt; border-top: Black 1pt solid">&nbsp;</DIV></DIV><!-- Field: /Rule-Page --></TD></TR>
  <TR>
    <TD STYLE="font-size: 11pt">&nbsp;</TD>
    <TD STYLE="font-size: 11pt">&nbsp;</TD>
    <TD STYLE="font-size: 11pt">&nbsp;</TD></TR>
  <TR STYLE="vertical-align: top">
    <TD>
    <P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0pt 0">&nbsp;/s/ James P. Scholhamer</P>
<!-- Field: Rule-Page --><DIV STYLE="margin-top: 1pt; margin-bottom: 1pt; width: 100%"><DIV STYLE="font-size: 1pt; border-top: Black 1pt solid">&nbsp;</DIV></DIV><!-- Field: /Rule-Page -->

    <P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0pt 0">James P. Scholhamer</P></TD>
    <TD>
    <P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0pt 0 0pt 12pt; text-align: center; text-indent: -12pt">Chief Executive
Officer</P>
    <P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0pt 0 0pt 12pt; text-align: center; text-indent: -12pt">(Principal Executive
Officer and Director)</P></TD>
    <TD STYLE="white-space: nowrap; font-size: 11pt; text-align: center"><FONT STYLE="font-size: 10pt">March 20, 2024</FONT></TD></TR>
  <TR>
    <TD STYLE="font-size: 11pt">&nbsp;</TD>
    <TD STYLE="font-size: 11pt">&nbsp;</TD>
    <TD STYLE="font-size: 11pt">&nbsp;</TD></TR>
  <TR STYLE="vertical-align: top">
    <TD>
    <P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0pt 0">/s/ Sheri Savage&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;</P>
<!-- Field: Rule-Page --><DIV STYLE="margin-top: 1pt; margin-bottom: 1pt; width: 100%"><DIV STYLE="font-size: 1pt; border-top: Black 1pt solid">&nbsp;</DIV></DIV><!-- Field: /Rule-Page -->

    <P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0pt 0"></P>
    <P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0pt 0">Sheri Savage</P></TD>
    <TD>
    <P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0pt 0 0pt 12pt; text-align: center; text-indent: -12pt">Chief Financial
Officer</P>
    <P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0pt 0 0pt 12pt; text-align: center; text-indent: -12pt">(Principal Financial
Officer)</P></TD>
    <TD STYLE="white-space: nowrap; font-size: 11pt; text-align: center"><FONT STYLE="font-size: 10pt">March 20, 2024</FONT></TD></TR>
  <TR>
    <TD STYLE="font-size: 11pt">&nbsp;</TD>
    <TD STYLE="font-size: 11pt">&nbsp;</TD>
    <TD STYLE="font-size: 11pt">&nbsp;</TD></TR>
  <TR STYLE="vertical-align: top">
    <TD>
    <P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0pt 0">/s/ Brian E. Harding&nbsp;&nbsp;&nbsp;</P>
<!-- Field: Rule-Page --><DIV STYLE="margin-top: 1pt; margin-bottom: 1pt; width: 100%"><DIV STYLE="font-size: 1pt; border-top: Black 1pt solid">&nbsp;</DIV></DIV><!-- Field: /Rule-Page -->

    <P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0pt 0"></P>
    <P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0pt 0">Brian E. Harding</P></TD>
    <TD>
    <P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0pt 0 0pt 12pt; text-align: center; text-indent: -12pt">Chief Accounting
    Officer</P>
    <P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0pt 0 0pt 12pt; text-align: center; text-indent: -12pt">(Principal Accounting
Officer)</P></TD>
    <TD STYLE="white-space: nowrap; font-size: 11pt; text-align: center"><FONT STYLE="font-size: 10pt">March 20, 2024</FONT></TD></TR>
  <TR>
    <TD STYLE="font-size: 11pt">&nbsp;</TD>
    <TD STYLE="padding-left: 0.5in; font-size: 11pt">&nbsp;</TD>
    <TD STYLE="font-size: 11pt">&nbsp;</TD></TR>
  <TR STYLE="vertical-align: top">
    <TD>
    <P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0pt 0">/s/ Clarence Granger</P>
<!-- Field: Rule-Page --><DIV STYLE="margin-top: 1pt; margin-bottom: 1pt; width: 100%"><DIV STYLE="font-size: 1pt; border-top: Black 1pt solid">&nbsp;</DIV></DIV><!-- Field: /Rule-Page -->

    <P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0pt 0">Clarence Granger</P></TD>
    <TD STYLE="padding-left: 12pt; font-size: 12pt; text-align: center; text-indent: -12pt"><FONT STYLE="font-size: 10pt">Director</FONT></TD>
    <TD STYLE="white-space: nowrap; font-size: 11pt; text-align: center"><FONT STYLE="font-size: 10pt">March 20, 2024</FONT></TD></TR>
  <TR>
    <TD STYLE="font-size: 11pt">&nbsp;</TD>
    <TD STYLE="font-size: 11pt">&nbsp;</TD>
    <TD STYLE="font-size: 11pt">&nbsp;</TD></TR>
  <TR STYLE="vertical-align: top">
    <TD>
    <P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0pt 0">/s/ David Ibnale</P>
<!-- Field: Rule-Page --><DIV STYLE="margin-top: 1pt; margin-bottom: 1pt; width: 100%"><DIV STYLE="font-size: 1pt; border-top: Black 1pt solid">&nbsp;</DIV></DIV><!-- Field: /Rule-Page -->

    <P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0pt 0">David Ibnale</P></TD>
    <TD STYLE="padding-left: 12pt; font-size: 12pt; text-align: center; text-indent: -12pt"><FONT STYLE="font-size: 10pt">Director</FONT></TD>
    <TD STYLE="white-space: nowrap; font-size: 11pt; text-align: center"><FONT STYLE="font-size: 10pt">March 20, 2024</FONT></TD></TR>
  <TR STYLE="vertical-align: top">
    <TD>&nbsp;</TD>
    <TD STYLE="padding-left: 12pt; font-size: 12pt; text-align: center; text-indent: -12pt">&nbsp;</TD>
    <TD STYLE="white-space: nowrap; font-size: 11pt; text-align: center">&nbsp;</TD></TR>
  <TR STYLE="vertical-align: top">
    <TD>
    <P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0pt 0">/s/ Emily Liggett</P>
<!-- Field: Rule-Page --><DIV STYLE="margin-top: 1pt; margin-bottom: 1pt; width: 100%"><DIV STYLE="font-size: 1pt; border-top: Black 1pt solid">&nbsp;</DIV></DIV><!-- Field: /Rule-Page -->

    <P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0pt 0">Emily Liggett</P></TD>
    <TD>
    <P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0pt 0 0pt 12pt; text-align: center; text-indent: -12pt">Director</P>
    <P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0pt 0 0pt 12pt; text-align: center; text-indent: -12pt">&nbsp;</P></TD>
    <TD STYLE="white-space: nowrap">
    <P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0pt 0; text-align: center">March 20, 2024</P>
    <P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0pt 0; text-align: center">&nbsp;</P></TD></TR>
  <TR>
    <TD STYLE="font-size: 11pt">&nbsp;</TD>
    <TD STYLE="font-size: 11pt">&nbsp;</TD>
    <TD STYLE="font-size: 11pt">&nbsp;</TD></TR>
  <TR STYLE="vertical-align: top">
    <TD>
    <P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0pt 0">/s/ Thomas Edman</P>
<!-- Field: Rule-Page --><DIV STYLE="margin-top: 1pt; margin-bottom: 1pt; width: 100%"><DIV STYLE="font-size: 1pt; border-top: Black 1pt solid">&nbsp;</DIV></DIV><!-- Field: /Rule-Page -->

    <P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0pt 0">Thomas Edman</P></TD>
    <TD STYLE="padding-left: 12pt; font-size: 12pt; text-align: center; text-indent: -12pt"><FONT STYLE="font-size: 10pt">Director</FONT></TD>
    <TD STYLE="white-space: nowrap; font-size: 11pt; text-align: center"><FONT STYLE="font-size: 10pt">March 20, 2024</FONT></TD></TR>
  <TR>
    <TD STYLE="font-size: 11pt">&nbsp;</TD>
    <TD STYLE="font-size: 11pt">&nbsp;</TD>
    <TD STYLE="font-size: 11pt">&nbsp;</TD></TR>
  <TR STYLE="vertical-align: top">
    <TD>
    <P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0pt 0">/s/ Barbara Scherer</P>
<!-- Field: Rule-Page --><DIV STYLE="margin-top: 1pt; margin-bottom: 1pt; width: 100%"><DIV STYLE="font-size: 1pt; border-top: Black 1pt solid">&nbsp;</DIV></DIV><!-- Field: /Rule-Page -->

    <P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0pt 0">Barbara Scherer</P></TD>
    <TD STYLE="padding-left: 12pt; font-size: 12pt; text-align: center; text-indent: -12pt"><FONT STYLE="font-size: 10pt">Director</FONT></TD>
    <TD STYLE="white-space: nowrap; font-size: 11pt; text-align: center"><FONT STYLE="font-size: 10pt">March 20, 2024</FONT></TD></TR>
</TABLE>

<P STYLE="margin: 0">&nbsp;</P>


<!-- Field: Page; Sequence: 6 -->
    <DIV STYLE="margin-bottom: 6pt; border-bottom: Black 1pt solid"><TABLE CELLPADDING="0" CELLSPACING="0" STYLE="width: 100%"><TR><TD STYLE="text-align: center; width: 100%">&nbsp;</TD></TR></TABLE></DIV>
    <DIV STYLE="break-before: page; margin-top: 6pt"><TABLE CELLPADDING="0" CELLSPACING="0" STYLE="width: 100%"><TR><TD STYLE="text-align: center; width: 100%">&nbsp;</TD></TR></TABLE></DIV>
    <!-- Field: /Page -->

<TABLE CELLSPACING="2" CELLPADDING="2" STYLE="font: 10pt Times New Roman, Times, Serif; width: 100%; border-collapse: collapse">
  <TR STYLE="vertical-align: bottom">
    <TD STYLE="white-space: nowrap">
    <P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0pt 0; text-align: center"><B>Signature</B></P>
<!-- Field: Rule-Page --><DIV STYLE="margin-top: 1pt; margin-bottom: 1pt; width: 100%"><DIV STYLE="font-size: 1pt; border-top: Black 1pt solid">&nbsp;</DIV></DIV><!-- Field: /Rule-Page --></TD>
    <TD STYLE="white-space: nowrap">
    <P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0pt 0; text-align: center"><B>Title</B></P>
<!-- Field: Rule-Page --><DIV STYLE="margin-top: 1pt; margin-bottom: 1pt; width: 100%"><DIV STYLE="font-size: 1pt; border-top: Black 1pt solid">&nbsp;</DIV></DIV><!-- Field: /Rule-Page --></TD>
    <TD STYLE="white-space: nowrap">
    <P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0pt 0; text-align: center"><B>Date</B></P>
<!-- Field: Rule-Page --><DIV STYLE="margin-top: 1pt; margin-bottom: 1pt; width: 100%"><DIV STYLE="font-size: 1pt; border-top: Black 1pt solid">&nbsp;</DIV></DIV><!-- Field: /Rule-Page --></TD></TR>
<TR STYLE="vertical-align: top">
    <TD>&nbsp;</TD>
    <TD STYLE="padding-left: 12pt; font-size: 12pt; text-align: center; text-indent: -12pt">&nbsp;</TD>
    <TD STYLE="white-space: nowrap; font-size: 11pt; text-align: center">&nbsp;</TD></TR>
  <TR STYLE="vertical-align: top">
    <TD STYLE="width: 42%">
    <P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0pt 0">/s/ Ernest Maddock</P>
<!-- Field: Rule-Page --><DIV STYLE="margin-top: 1pt; margin-bottom: 1pt; width: 100%"><DIV STYLE="font-size: 1pt; border-top: Black 1pt solid">&nbsp;</DIV></DIV><!-- Field: /Rule-Page -->

    <P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0pt 0">Ernest Maddock</P></TD>
    <TD STYLE="width: 38%; padding-left: 12pt; font-size: 12pt; text-align: center; text-indent: -12pt"><FONT STYLE="font-size: 10pt">Director</FONT></TD>
    <TD STYLE="white-space: nowrap; width: 20%; font-size: 11pt; text-align: center"><FONT STYLE="font-size: 10pt">March 20, 2024</FONT></TD></TR>
  <TR STYLE="vertical-align: top">
    <TD STYLE="font-size: 12pt">&nbsp;</TD>
    <TD STYLE="padding-left: 12pt; font-size: 12pt; text-align: center; text-indent: -12pt">&nbsp;</TD>
    <TD STYLE="white-space: nowrap; font-size: 11pt; text-align: center">&nbsp;</TD></TR>
  <TR STYLE="vertical-align: top">
    <TD>
    <P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0pt 0">/s/ Jackie Seto</P>
<!-- Field: Rule-Page --><DIV STYLE="margin-top: 1pt; margin-bottom: 1pt; width: 100%"><DIV STYLE="font-size: 1pt; border-top: Black 1pt solid">&nbsp;</DIV></DIV><!-- Field: /Rule-Page -->

    <P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0pt 0">Jackie Seto</P></TD>
    <TD STYLE="padding-left: 12pt; font-size: 12pt; text-align: center; text-indent: -12pt"><FONT STYLE="font-size: 10pt">Director</FONT></TD>
    <TD STYLE="white-space: nowrap; font-size: 11pt; text-align: center"><FONT STYLE="font-size: 10pt">March 20, 2024</FONT></TD></TR>
  </TABLE>

<P STYLE="margin-top: 0; margin-bottom: 0">&nbsp;</P>

<!-- Field: Page; Sequence: 7; Options: Last -->
    <DIV STYLE="margin-bottom: 6pt; border-bottom: Black 1pt solid"><TABLE CELLPADDING="0" CELLSPACING="0" STYLE="width: 100%"><TR><TD STYLE="text-align: center; width: 100%">&nbsp;</TD></TR></TABLE></DIV>
    <!-- Field: /Page -->

<P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0pt 0; text-align: center"></P>

<P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0pt 0"></P>

</BODY>
</HTML>
[{"type": "S-8", "sequence": "1", "filename": "dp208624_s8.htm", "description": "FORM S-8", "secsgml_size_bytes": 42106}]
{"company-data": {"conformed-name": "Ultra Clean Holdings, Inc.", "cik": "0001275014", "assigned-sic": "3674", "organization-name": "04 Manufacturing", "irs-number": "611430858", "state-of-incorporation": "DE", "fiscal-year-end": "1230"}, "filing-values": {"form-type": "S-8", "act": "33", "file-number": "333-278114", "film-number": "24768630"}, "business-address": {"street1": "26462 CORPORATE AVENUE", "city": "HAYWARD", "state": "CA", "zip": "94545", "phone": "(510) 576-4400"}, "mail-address": {"street1": "26462 CORPORATE AVENUE", "city": "HAYWARD", "state": "CA", "zip": "94545"}, "former-company": {"former-conformed-name": "ULTRA CLEAN HOLDINGS INC", "date-changed": "20031231"}}
As filed with the Securities and Exchange Commission
on March 20, 2024
Registration No. 333-
UNITED STATES
SECURITIES AND EXCHANGE COMMISSION
Washington, D.C. 20549
FORM S-8
REGISTRATION STATEMENT UNDER
THE SECURITIES ACT OF 1933
ULTRA CLEAN HOLDINGS, INC.
(Exact Name of Registrant as Specified in its Charter)
Delaware
61-1430858
(State or Other Jurisdiction of
Incorporation or Organization)
(I.R.S. Employer
Identification No.)
26462 CORPORATE AVENUE
HAYWARD, CA 94545
(Address of Principal Executive Offices)
Ultra Clean Holdings, Inc. Amended and Restated
Stock Incentive Plan
Ultra Clean Holdings, Inc. Amended and Restated Employee Stock Purchase Plan
(Full Titles of the Plans)
James P. Scholhamer
Chief Executive Officer
Ultra Clean Holdings,
Inc.
26462 Corporate Avenue
Hayward, CA 94545
(510) 576-4600 (Name,
Address, Including Zip Code, and
Telephone Number, Including Area Code, of Agent For Service
With copies to:
Alan F. Denenberg, Esq.
Davis Polk & Wardwell LLP
1600 El Camino Real
Menlo Park, California 94025
(650) 752-2000
Indicate by check mark whether the registrant is a large accelerated
filer, an accelerated filer, a non-accelerated filer, a smaller reporting company or an emerging growth company. See the definitions
of "large accelerated filer," "accelerated filer, " "smaller reporting company" and "emerging
growth company" in Rule 12b-2 of the Exchange Act.
Large accelerated filer
☒
Accelerated filer
☐
Non-accelerated filer
☐
(Do
    not check if a smaller reporting company)
Smaller reporting company
☐
Emerging Growth Company
☐
If an emerging growth company, indicate
by check mark if the registrant has elected not to use the extended transition period for complying with any new or revised financial
accounting standards provided pursuant to Section 7(a)(2)(B) of the Securities Act.
☐
EXPLANATORY NOTE
Pursuant to General Instruction E to Form S-8,
Ultra Clean Holdings, Inc. (the "Registrant") is filing this Registration Statement on Form S-8 (this "Registration
Statement") with the U.S. Securities and Exchange Commission (the "Commission") to register additional 2,000,000 shares
of common stock of the Registrant for issuance under the Registrant's Amended and Restated Stock Incentive Plan (the "Stock
Plan") and 500,000 shares of common stock of the Registrant for issuance under the Registrant's Employee Stock Purchase Plan
("ESPP"). These additional shares of common stock are securities of the same class and relate to the same employee benefit
plan (as amended from time to time) as other securities for which a registration statement on Form S-8 has been filed with the Securities
and Exchange Commission on March 30, 2004 (File No.
333-114051
),
April 4, 2005 (File No.
333-123820
), June
19, 2006 (File No.
333-135147
), April
9, 2007 (File No.
333-141989
), May 30,
2008 (File No.
333-151335
), March 19,
2009 (File No.
333-158108
), March 30,
2010 (File No.
333-165782
), June 15, 2010
(File No.
333-167530
), May 31, 2013 (File
No.
333-188995
), July 25, 2017 (File No.
333-219447
) and December 18,
2019 (File No.
333-235574
), the contents
of which are hereby incorporated by reference. These additional shares of common stock have become reserved for issuance as a result of
the amendment and restatement of (i) the Registrant's Amended and Restated Stock Incentive Plan, effective as of May 17, 2023 and
(ii) the Registrant's Amended and Restated Employee Stock Purchase Plan, effective as of May 17, 2023.
PART II
INFORMATION REQUIRED IN THE REGISTRATION STATEMENT
Item 3. Incorporation of Documents by Reference.
The following documents filed by the Registrant
with the Commission under the Securities Act of 1933, as amended (the "Securities Act") or the Securities Exchange Act of
1934, as amended (the "Exchange Act"), are incorporated herein by reference:
(a)
The Registrant's Annual Report on Form 10-K for the fiscal year ended December 29, 2023 filed with the Commission on March 6,
2024 (File No.
000-50646
)
(the "Annual Report);
(b)
All other reports filed by the Registrant pursuant to Section 13(a) or Section 15(d) of the Exchange Act, since December 29, 2023
(other than Current Reports furnished under Item 2.02 or Item 7.01 of Form 8-K and exhibits furnished on that form that relate to such
items); and
(c)
The description of the Registrant's common stock contained in
Exhibit
4.2
to the Registrant's Annual Report, including any amendments or reports filed for the purpose of updating such description.
In addition, all documents subsequently filed
by the Registrant pursuant to Sections 13(a), 13(c), 14 and 15(d) of the Exchange Act (other than documents or any information therein
deemed to have been furnished and not filed in accordance with rules of the Commission), prior to the filing of a post-effective amendment
to this Registration Statement, which indicates that all securities offered have been sold or which deregisters all securities then remaining
unsold, shall be deemed to be incorporated by reference in this Registration Statement and to be a part hereof from the date of the filing
of such documents.
Any statement contained in a document incorporated
or deemed to be incorporated by reference herein shall be deemed to be modified or superseded for purposes of this Registration Statement
to the extent that a statement contained herein (or in any other subsequently filed document which also is incorporated or deemed to be
incorporated by reference herein), modifies or supersedes such statement. Any such statement so modified or superseded shall not be deemed,
except as so modified or superseded, to constitute a part of this Registration Statement.
Item 8. Exhibits.
Exhibit Number
4.1
Form of Amended and Restated Certificate of Incorporation (incorporated by reference to Exhibit
3.1
of the Registrant's Annual Report)
5.1*
Opinion of Davis Polk & Wardwell LLP
23.1*
Consent of Moss Adams LLP, independent registered public accounting firm
23.2*
Consent of Davis Polk & Wardwell LLP (included in Exhibit 5.1)
24.1*
Powers of Attorney (included on signature page)
99.1
Ultra Clean Holdings, Inc. Amended and Restated Stock Incentive Plan (incorporated by reference to Exhibit
10.1
of the Registrant's Annual Report)
99.2
Ultra Clean Holdings, Inc. Employee Stock Purchase Plan (incorporated by reference to Exhibit
10.5
of the Registrant's Annual Report)
107*
Filing Fee Table
*       Filed
herewith.
SIGNATURES
Pursuant to the requirements of the Securities
Act, the Registrant, Ultra Clean Holdings, Inc., certifies that it has reasonable grounds to believe that it meets all of the requirements
for filing on Form S-8 and has duly caused this Registration Statement to be signed on its behalf by the undersigned, thereunto duly authorized,
in the City of Hayward, State of California, on the 20
th
day of March, 2024.
ULTRA CLEAN HOLDINGS, INC.
By:
/s/ James P. Scholhamer
Name:
James P. Scholhamer
Title:
Chief Executive Officer
POWER OF ATTORNEY AND SIGNATURES
Know all persons by these presents, that each
person whose signature appears below constitutes and appoints James P. Scholhamer and Sheri Savage and each of them, as his or her true
and lawful attorney-in-fact and agents, upon the action of such appointee, with full power of substitution and resubstitution, to do any
and all acts and things and execute, in the name of the undersigned, any and all instruments which each of said attorneys-in-fact and
agents may deem necessary or advisable in order to enable Ultra Clean Holdings, Inc, to comply with the Securities Act, and any requirements
of the Commission in respect thereof, in connection with the filing with the Commission of this Registration Statement under the Securities
Act, including specifically but without limitation, power and authority to sign the name of the undersigned to such Registration Statement,
and any amendments to such Registration Statement (including post-effective amendments), and to file the same with all exhibits thereto
and other documents in connection therewith, with the Commission, to sign any and all applications, registration statements, notices or
other documents necessary or advisable to comply with applicable state securities laws, and to file the same, together with other documents
in connection therewith with the appropriate state securities authorities, granting unto each of said attorneys-in-fact and agents full
power and authority to do and to perform each and every act and thing requisite or necessary to be done in and about the premises, as
fully and to all intents and purposes as the undersigned might or could do in person, hereby ratifying and confirming all that each of
said attorneys-in-fact and agents may lawfully do or cause to be done by virtue hereof.
Pursuant to the requirements of the Securities
Act, this Registration Statement has been signed by the following persons in the capacities and on the dates indicated:
Signature
Title
Date
/s/ James P. Scholhamer
James P. Scholhamer
Chief Executive
Officer
(Principal Executive
Officer and Director)
March 20, 2024
/s/ Sheri Savage
Sheri Savage
Chief Financial
Officer
(Principal Financial
Officer)
March 20, 2024
/s/ Brian E. Harding
Brian E. Harding
Chief Accounting
    Officer
(Principal Accounting
Officer)
March 20, 2024
/s/ Clarence Granger
Clarence Granger
Director
March 20, 2024
/s/ David Ibnale
David Ibnale
Director
March 20, 2024
/s/ Emily Liggett
Emily Liggett
Director
March 20, 2024
/s/ Thomas Edman
Thomas Edman
Director
March 20, 2024
/s/ Barbara Scherer
Barbara Scherer
Director
March 20, 2024
Signature
Title
Date
/s/ Ernest Maddock
Ernest Maddock
Director
March 20, 2024
/s/ Jackie Seto
Jackie Seto
Director
March 20, 2024