Ultra Clean Holdings, Inc. 10-Q

ITEM 5. Other Information None. - 34 - ITEM 6. E xhibits (a) Exhibits The following exhibits are filed with this quarterly Report on Form 10-Q for the quarter ended September 29, 2023: Exhibit Number Description 31.1 Certification of Chief Executive Officer pursuant to Section 302 of the Sarbanes-Oxley Act of 2002. 31.2 Certification of Chief Financial Officer pursuant to Section 302 of the Sarbanes-Oxley Act of 2002. 32.1 Certification of the Chief Executive Officer and the Chief Financial Officer pursuant to 18 U.S.C. Section 1350, as adopted pursuant to Section 906 of the Sarbanes-Oxley Act of 2002. 101.INS Inline XBRL Instance Document – the instance document does not appear in the Interactive Data File because its XBRL tags are embedded within the Inline XBRL document. 101.SCH Inline XBRL Taxonomy Extension Schema Document 101.CAL Inline XBRL Taxonomy Calculation Linkbase Document 101.DEF Inline XBRL Taxonomy Definition Linkbase Document 101.LAB Inline XBRL Taxonomy Label Linkbase Document 101.PRE Inline XBRL Taxonomy Extension Presentation Linkbase Document 104 Cover Page Interactive Data File (formatted as inline XBRL and contained in Exhibit 101) - 35 - SIGNAT URES Pursuant to the requirements of the Securities Exchange Act of 1934, the Registrant has duly caused this report to be signed on its behalf by the undersigned thereunto duly authorized. ULTRA CLEAN HOLDINGS, INC. (Registrant) Date: November 7, 2023 By: /S/ JAMES P. SCHOLHAMER Name: James P. Scholhamer Title: Chief Executive Officer (Principal Executive Officer and duly authorized signatory) Date: November 7, 2023 By: /S/ SHERI SAVAGE Name: Sheri Savage Title: Chief Financial Officer (Principal Financial Officer and duly authorized signatory) - 36 -