<?xml version="1.0" encoding="UTF-8"?>

<!--XBRL Document Created with the Workiva Platform-->
<!--Copyright 2026 Workiva-->
<!--r:019e65c5-2e17-70aa-952d-e76d45c38e22,g:6c7fc4b0-3c2a-40cd-a1be-f8cb12912fde-->
<xs:schema xmlns:xs="http://www.w3.org/2001/XMLSchema" xmlns:link="http://www.xbrl.org/2003/linkbase" xmlns:uctt="http://www.uct.com/20260626" xmlns:xbrli="http://www.xbrl.org/2003/instance" xmlns:dtr-types="http://www.xbrl.org/dtr/type/2024-01-31" xmlns:xbrldt="http://xbrl.org/2005/xbrldt" attributeFormDefault="unqualified" elementFormDefault="qualified" targetNamespace="http://www.uct.com/20260626">
  <xs:import namespace="http://fasb.org/srt/2026" schemaLocation="https://xbrl.fasb.org/srt/2026/elts/srt-2026.xsd"/>
  <xs:import namespace="http://fasb.org/us-gaap/2026" schemaLocation="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd"/>
  <xs:import namespace="http://www.xbrl.org/2003/instance" schemaLocation="http://www.xbrl.org/2003/xbrl-instance-2003-12-31.xsd"/>
  <xs:import namespace="http://www.xbrl.org/2003/linkbase" schemaLocation="http://www.xbrl.org/2003/xbrl-linkbase-2003-12-31.xsd"/>
  <xs:import namespace="http://www.xbrl.org/dtr/type/2024-01-31" schemaLocation="https://www.xbrl.org/dtr/type/2024-01-31/types.xsd"/>
  <xs:import namespace="http://xbrl.org/2005/xbrldt" schemaLocation="http://www.xbrl.org/2005/xbrldt-2005.xsd"/>
  <xs:import namespace="http://xbrl.sec.gov/country/2026" schemaLocation="https://xbrl.sec.gov/country/2026/country-2026.xsd"/>
  <xs:import namespace="http://xbrl.sec.gov/dei/2026" schemaLocation="https://xbrl.sec.gov/dei/2026/dei-2026.xsd"/>
  <xs:import namespace="http://xbrl.sec.gov/ecd/2026" schemaLocation="https://xbrl.sec.gov/ecd/2026/ecd-2026.xsd"/>
  <xs:annotation>
    <xs:appinfo>
      <link:linkbaseRef xmlns:xlink="http://www.w3.org/1999/xlink" xlink:arcrole="http://www.w3.org/1999/xlink/properties/linkbase" xlink:href="uctt-20260626_pre.xml" xlink:role="http://www.xbrl.org/2003/role/presentationLinkbaseRef" xlink:type="simple"/>
      <link:linkbaseRef xmlns:xlink="http://www.w3.org/1999/xlink" xlink:arcrole="http://www.w3.org/1999/xlink/properties/linkbase" xlink:href="uctt-20260626_def.xml" xlink:role="http://www.xbrl.org/2003/role/definitionLinkbaseRef" xlink:type="simple"/>
      <link:linkbaseRef xmlns:xlink="http://www.w3.org/1999/xlink" xlink:arcrole="http://www.w3.org/1999/xlink/properties/linkbase" xlink:href="uctt-20260626_lab.xml" xlink:role="http://www.xbrl.org/2003/role/labelLinkbaseRef" xlink:type="simple"/>
      <link:linkbaseRef xmlns:xlink="http://www.w3.org/1999/xlink" xlink:arcrole="http://www.w3.org/1999/xlink/properties/linkbase" xlink:href="uctt-20260626_cal.xml" xlink:role="http://www.xbrl.org/2003/role/calculationLinkbaseRef" xlink:type="simple"/>
      <link:roleType id="Cover" roleURI="http://www.uct.com/role/Cover">
        <link:definition>0000001 - Document - Cover</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType id="CondensedConsolidatedBalanceSheets" roleURI="http://www.uct.com/role/CondensedConsolidatedBalanceSheets">
        <link:definition>9952151 - Statement - Condensed Consolidated Balance Sheets</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType id="CondensedConsolidatedBalanceSheetsParenthetical" roleURI="http://www.uct.com/role/CondensedConsolidatedBalanceSheetsParenthetical">
        <link:definition>9952152 - Statement - Condensed Consolidated Balance Sheets (Parenthetical)</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType id="CondensedConsolidatedStatementsofOperations" roleURI="http://www.uct.com/role/CondensedConsolidatedStatementsofOperations">
        <link:definition>9952153 - Statement - Condensed Consolidated Statements of Operations</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType id="CondensedConsolidatedStatementsofComprehensiveIncomeLoss" roleURI="http://www.uct.com/role/CondensedConsolidatedStatementsofComprehensiveIncomeLoss">
        <link:definition>9952154 - Statement - Condensed Consolidated Statements of Comprehensive Income (Loss)</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType id="CondensedConsolidatedStatementsofCashFlows" roleURI="http://www.uct.com/role/CondensedConsolidatedStatementsofCashFlows">
        <link:definition>9952155 - Statement - Condensed Consolidated Statements of Cash Flows</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType id="CondensedConsolidatedStatementsofStockholdersEquity" roleURI="http://www.uct.com/role/CondensedConsolidatedStatementsofStockholdersEquity">
        <link:definition>9952156 - Statement - Condensed Consolidated Statements of Stockholders' Equity</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType id="OrganizationandSignificantAccountingPolicies" roleURI="http://www.uct.com/role/OrganizationandSignificantAccountingPolicies">
        <link:definition>9952157 - Disclosure - Organization and Significant Accounting Policies</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType id="BalanceSheetInformation" roleURI="http://www.uct.com/role/BalanceSheetInformation">
        <link:definition>9952158 - Disclosure - Balance Sheet Information</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType id="FairValue" roleURI="http://www.uct.com/role/FairValue">
        <link:definition>9952159 - Disclosure - Fair Value</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType id="GoodwillandIntangibleAssets" roleURI="http://www.uct.com/role/GoodwillandIntangibleAssets">
        <link:definition>9952160 - Disclosure - Goodwill and Intangible Assets</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType id="LongTermDebt" roleURI="http://www.uct.com/role/LongTermDebt">
        <link:definition>9952161 - Disclosure - Long-Term Debt</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType id="IncomeTaxes" roleURI="http://www.uct.com/role/IncomeTaxes">
        <link:definition>9952162 - Disclosure - Income Taxes</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType id="RetirementPlans" roleURI="http://www.uct.com/role/RetirementPlans">
        <link:definition>9952163 - Disclosure - Retirement Plans</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType id="CommitmentsandContingencies" roleURI="http://www.uct.com/role/CommitmentsandContingencies">
        <link:definition>9952164 - Disclosure - Commitments and Contingencies</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType id="StockholdersEquityandNoncontrollingInterests" roleURI="http://www.uct.com/role/StockholdersEquityandNoncontrollingInterests">
        <link:definition>9952165 - Disclosure - Stockholders' Equity and Noncontrolling Interests</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType id="EmployeeStockPlans" roleURI="http://www.uct.com/role/EmployeeStockPlans">
        <link:definition>9952166 - Disclosure - Employee Stock Plans</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType id="RevenueRecognition" roleURI="http://www.uct.com/role/RevenueRecognition">
        <link:definition>9952167 - Disclosure - Revenue Recognition</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType id="Leases" roleURI="http://www.uct.com/role/Leases">
        <link:definition>9952168 - Disclosure - Leases</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType id="NetIncomeLossPerShare" roleURI="http://www.uct.com/role/NetIncomeLossPerShare">
        <link:definition>9952169 - Disclosure - Net Income (Loss) Per Share</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType id="ReportableSegments" roleURI="http://www.uct.com/role/ReportableSegments">
        <link:definition>9952170 - Disclosure - Reportable Segments</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType id="OrganizationandSignificantAccountingPoliciesPolicies" roleURI="http://www.uct.com/role/OrganizationandSignificantAccountingPoliciesPolicies">
        <link:definition>9955511 - Disclosure - Organization and Significant Accounting Policies (Policies)</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType id="BalanceSheetInformationTables" roleURI="http://www.uct.com/role/BalanceSheetInformationTables">
        <link:definition>9955512 - Disclosure - Balance Sheet Information (Tables)</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType id="FairValueTables" roleURI="http://www.uct.com/role/FairValueTables">
        <link:definition>9955513 - Disclosure - Fair Value (Tables)</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType id="GoodwillandIntangibleAssetsTables" roleURI="http://www.uct.com/role/GoodwillandIntangibleAssetsTables">
        <link:definition>9955514 - Disclosure - Goodwill and Intangible Assets (Tables)</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType id="LongTermDebtTables" roleURI="http://www.uct.com/role/LongTermDebtTables">
        <link:definition>9955515 - Disclosure - Long-Term Debt (Tables)</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType id="RetirementPlansTables" roleURI="http://www.uct.com/role/RetirementPlansTables">
        <link:definition>9955516 - Disclosure - Retirement Plans (Tables)</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType id="EmployeeStockPlansTables" roleURI="http://www.uct.com/role/EmployeeStockPlansTables">
        <link:definition>9955517 - Disclosure - Employee Stock Plans (Tables)</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType id="RevenueRecognitionTables" roleURI="http://www.uct.com/role/RevenueRecognitionTables">
        <link:definition>9955518 - Disclosure - Revenue Recognition (Tables)</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType id="NetIncomeLossPerShareTables" roleURI="http://www.uct.com/role/NetIncomeLossPerShareTables">
        <link:definition>9955519 - Disclosure - Net Income (Loss) Per Share (Tables)</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType id="ReportableSegmentsTables" roleURI="http://www.uct.com/role/ReportableSegmentsTables">
        <link:definition>9955520 - Disclosure - Reportable Segments (Tables)</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType id="BalanceSheetInformationAdditionalInformationDetails" roleURI="http://www.uct.com/role/BalanceSheetInformationAdditionalInformationDetails">
        <link:definition>9955521 - Disclosure - Balance Sheet Information - Additional Information (Details)</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType id="BalanceSheetInformationSummaryofInventoriesDetails" roleURI="http://www.uct.com/role/BalanceSheetInformationSummaryofInventoriesDetails">
        <link:definition>9955522 - Disclosure - Balance Sheet Information - Summary of Inventories (Details)</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType id="BalanceSheetInformationPropertyPlantandEquipmentNetDetails" roleURI="http://www.uct.com/role/BalanceSheetInformationPropertyPlantandEquipmentNetDetails">
        <link:definition>9955523 - Disclosure - Balance Sheet Information - Property, Plant and Equipment, Net (Details)</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType id="FairValueScheduleofFairValueAssetsandLiabilitiesMeasuredDetails" roleURI="http://www.uct.com/role/FairValueScheduleofFairValueAssetsandLiabilitiesMeasuredDetails">
        <link:definition>9955524 - Disclosure - Fair Value - Schedule of Fair Value, Assets and Liabilities Measured (Details)</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType id="FairValueAdditionalInformationDetails" roleURI="http://www.uct.com/role/FairValueAdditionalInformationDetails">
        <link:definition>9955525 - Disclosure - Fair Value - Additional Information (Details)</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType id="GoodwillandIntangibleAssetsAdditionalInformationDetails" roleURI="http://www.uct.com/role/GoodwillandIntangibleAssetsAdditionalInformationDetails">
        <link:definition>9955526 - Disclosure - Goodwill and Intangible Assets - Additional Information (Details)</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType id="GoodwillandIntangibleAssetsDetailsofGoodwillDetails" roleURI="http://www.uct.com/role/GoodwillandIntangibleAssetsDetailsofGoodwillDetails">
        <link:definition>9955527 - Disclosure - Goodwill and Intangible Assets - Details of Goodwill (Details)</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType id="GoodwillandIntangibleAssetsPurchasedIntangibleAssetsDetails" roleURI="http://www.uct.com/role/GoodwillandIntangibleAssetsPurchasedIntangibleAssetsDetails">
        <link:definition>9955528 - Disclosure - Goodwill and Intangible Assets - Purchased Intangible Assets (Details)</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType id="GoodwillandIntangibleAssetsFutureEstimatedAmortizationExpenseDetails" roleURI="http://www.uct.com/role/GoodwillandIntangibleAssetsFutureEstimatedAmortizationExpenseDetails">
        <link:definition>9955529 - Disclosure - Goodwill and Intangible Assets - Future Estimated Amortization Expense (Details)</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType id="LongTermDebtScheduleofLongTermDebtDetails" roleURI="http://www.uct.com/role/LongTermDebtScheduleofLongTermDebtDetails">
        <link:definition>9955530 - Disclosure - Long-Term Debt - Schedule of Long Term Debt (Details)</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType id="LongTermDebtTermandRevolvingCreditFacilitiesDetails" roleURI="http://www.uct.com/role/LongTermDebtTermandRevolvingCreditFacilitiesDetails">
        <link:definition>9955531 - Disclosure - Long-Term Debt - Term and Revolving Credit Facilities (Details)</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType id="LongTermDebtConvertibleSeniorNotesandRelatedCappedCallTransactionsDetails" roleURI="http://www.uct.com/role/LongTermDebtConvertibleSeniorNotesandRelatedCappedCallTransactionsDetails">
        <link:definition>9955532 - Disclosure - Long-Term Debt - Convertible Senior Notes and Related Capped Call Transactions (Details)</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType id="LongTermDebtScheduleofNetCarryingAmountoftheLiabilityComponentoftheNotesDetails" roleURI="http://www.uct.com/role/LongTermDebtScheduleofNetCarryingAmountoftheLiabilityComponentoftheNotesDetails">
        <link:definition>9955533 - Disclosure - Long-Term Debt - Schedule of Net Carrying Amount of the Liability Component of the Notes (Details)</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType id="IncomeTaxesDetails" roleURI="http://www.uct.com/role/IncomeTaxesDetails">
        <link:definition>9955534 - Disclosure - Income Taxes (Details)</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType id="RetirementPlansAdditionalInformationDetails" roleURI="http://www.uct.com/role/RetirementPlansAdditionalInformationDetails">
        <link:definition>9955535 - Disclosure - Retirement Plans - Additional Information (Details)</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType id="RetirementPlansScheduleofFuturePaymentObligationsDetails" roleURI="http://www.uct.com/role/RetirementPlansScheduleofFuturePaymentObligationsDetails">
        <link:definition>9955536 - Disclosure - Retirement Plans - Schedule of Future Payment Obligations (Details)</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType id="StockholdersEquityandNoncontrollingInterestsDetails" roleURI="http://www.uct.com/role/StockholdersEquityandNoncontrollingInterestsDetails">
        <link:definition>9955537 - Disclosure - Stockholders' Equity and Noncontrolling Interests (Details)</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType id="EmployeeStockPlansAdditionalInformationDetails" roleURI="http://www.uct.com/role/EmployeeStockPlansAdditionalInformationDetails">
        <link:definition>9955538 - Disclosure - Employee Stock Plans - Additional Information (Details)</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType id="EmployeeStockPlansSummaryofStockBasedCompensationExpenseIncludedinCondensedConsolidatedStatementsofOperationsDetails" roleURI="http://www.uct.com/role/EmployeeStockPlansSummaryofStockBasedCompensationExpenseIncludedinCondensedConsolidatedStatementsofOperationsDetails">
        <link:definition>9955539 - Disclosure - Employee Stock Plans - Summary of Stock-Based Compensation Expense Included in Condensed Consolidated Statements of Operations (Details)</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType id="EmployeeStockPlansSummaryofStockBasedCompensationExpenseIncludedinCondensedConsolidatedStatementsofOperationsDetails_1" roleURI="http://www.uct.com/role/EmployeeStockPlansSummaryofStockBasedCompensationExpenseIncludedinCondensedConsolidatedStatementsofOperationsDetails_1">
        <link:definition>9955539 - Disclosure - Employee Stock Plans - Summary of Stock-Based Compensation Expense Included in Condensed Consolidated Statements of Operations (Details)</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType id="EmployeeStockPlansSummaryofRestrictedStockUnitPerformanceStockUnitsandRestrictedStockAwardActivityDetails" roleURI="http://www.uct.com/role/EmployeeStockPlansSummaryofRestrictedStockUnitPerformanceStockUnitsandRestrictedStockAwardActivityDetails">
        <link:definition>9955540 - Disclosure - Employee Stock Plans - Summary of Restricted Stock Unit, Performance Stock Units and Restricted Stock Award Activity (Details)</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType id="RevenueRecognitionAdditionalInformationDetails" roleURI="http://www.uct.com/role/RevenueRecognitionAdditionalInformationDetails">
        <link:definition>9955541 - Disclosure - Revenue Recognition - Additional Information (Details)</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType id="RevenueRecognitionSummaryofRevenuebyGeographicAreaDetails" roleURI="http://www.uct.com/role/RevenueRecognitionSummaryofRevenuebyGeographicAreaDetails">
        <link:definition>9955542 - Disclosure - Revenue Recognition - Summary of Revenue by Geographic Area (Details)</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType id="RevenueRecognitionSummaryoftheMostSignificantCustomersDetails" roleURI="http://www.uct.com/role/RevenueRecognitionSummaryoftheMostSignificantCustomersDetails">
        <link:definition>9955543 - Disclosure - Revenue Recognition - Summary of the Most Significant Customers (Details)</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType id="NetIncomeLossPerShareSummaryofBasicandDilutedNetIncomePerShareDetails" roleURI="http://www.uct.com/role/NetIncomeLossPerShareSummaryofBasicandDilutedNetIncomePerShareDetails">
        <link:definition>9955544 - Disclosure - Net Income (Loss) Per Share - Summary of Basic and Diluted Net Income Per Share (Details)</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType id="NetIncomeLossPerShareSummaryofOutstandingPotentiallyDilutiveShareswereExcludedFromtheCalculationofDilutedNetIncomeLossPerShareofCommonStockDetails" roleURI="http://www.uct.com/role/NetIncomeLossPerShareSummaryofOutstandingPotentiallyDilutiveShareswereExcludedFromtheCalculationofDilutedNetIncomeLossPerShareofCommonStockDetails">
        <link:definition>9955545 - Disclosure - Net Income (Loss) Per Share - Summary of Outstanding Potentially Dilutive Shares were Excluded From the Calculation of Diluted Net Income (Loss) Per Share of Common Stock (Details)</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType id="ReportableSegmentsAdditionalInformationDetails" roleURI="http://www.uct.com/role/ReportableSegmentsAdditionalInformationDetails">
        <link:definition>9955546 - Disclosure - Reportable Segments - Additional Information (Details)</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType id="ReportableSegmentsSummaryofSegmentDataDetails" roleURI="http://www.uct.com/role/ReportableSegmentsSummaryofSegmentDataDetails">
        <link:definition>9955547 - Disclosure - Reportable Segments - Summary of Segment Data (Details)</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
    </xs:appinfo>
  </xs:annotation>
  <xs:element id="uctt_AmortizationOfFiniteLivedIntangibles" abstract="false" name="AmortizationOfFiniteLivedIntangibles" nillable="true" xbrli:periodType="duration" xbrli:balance="debit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="uctt_IncreaseDecreaseInOperatingLeaseAssetsAndLiabilitiesNet" abstract="false" name="IncreaseDecreaseInOperatingLeaseAssetsAndLiabilitiesNet" nillable="true" xbrli:periodType="duration" xbrli:balance="credit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="uctt_PaymentForCappedCallTransactions" abstract="false" name="PaymentForCappedCallTransactions" nillable="true" xbrli:periodType="duration" xbrli:balance="credit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="uctt_SharesTransferToEmployeeStockPlansShares" abstract="false" name="SharesTransferToEmployeeStockPlansShares" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="xbrli:sharesItemType"/>
  <xs:element id="uctt_AdjustmentsToAdditionalPaidInCapitalConvertibleDebtCappedCallTransactions" abstract="false" name="AdjustmentsToAdditionalPaidInCapitalConvertibleDebtCappedCallTransactions" nillable="true" xbrli:periodType="duration" xbrli:balance="debit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="uctt_ScheduleOfFuturePaymentObligationsTableTextBlock" abstract="false" name="ScheduleOfFuturePaymentObligationsTableTextBlock" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:textBlockItemType"/>
  <xs:element id="uctt_TransferOfFinancialAssetsAccountedForAsSalesMaximumUncollectableReceivablesApprovedToBeSold" abstract="false" name="TransferOfFinancialAssetsAccountedForAsSalesMaximumUncollectableReceivablesApprovedToBeSold" nillable="true" xbrli:periodType="instant" xbrli:balance="credit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="uctt_ComputerEquipmentAndSoftwareMember" abstract="true" name="ComputerEquipmentAndSoftwareMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="uctt_PropertyPlantAndEquipmentNetExcludingConstructionInProgress" abstract="false" name="PropertyPlantAndEquipmentNetExcludingConstructionInProgress" nillable="true" xbrli:periodType="instant" xbrli:balance="debit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="uctt_PlanAssetsMember" abstract="true" name="PlanAssetsMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="uctt_SemiconductorProductsAndSolutionsMember" abstract="true" name="SemiconductorProductsAndSolutionsMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="uctt_SemiconductorServicesBusinessMember" abstract="true" name="SemiconductorServicesBusinessMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="uctt_RecipesMember" abstract="true" name="RecipesMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="uctt_StandardOperatingProceduresMember" abstract="true" name="StandardOperatingProceduresMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="uctt_UctTradeNameMember" abstract="true" name="UctTradeNameMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="uctt_FiniteLivedIntangibleAssetsAmortizationExpenseAfterYearFour" abstract="false" name="FiniteLivedIntangibleAssetsAmortizationExpenseAfterYearFour" nillable="true" xbrli:periodType="instant" xbrli:balance="debit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="uctt_TermLoanCreditFacilityMember" abstract="true" name="TermLoanCreditFacilityMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="uctt_CreditAgreementMember" abstract="true" name="CreditAgreementMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="uctt_ConvertibleSeniorNotesDue2031Member" abstract="true" name="ConvertibleSeniorNotesDue2031Member" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="uctt_BankDebtMember" abstract="true" name="BankDebtMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="uctt_DebtInstrumentCovenantConsolidatedSecuredNetLeverageRatioMaximum" abstract="false" name="DebtInstrumentCovenantConsolidatedSecuredNetLeverageRatioMaximum" nillable="true" xbrli:periodType="instant" substitutionGroup="xbrli:item" type="xbrli:pureItemType"/>
  <xs:element id="uctt_DebtInstrumentCovenantConsolidatedSecuredNetLeverageRatioAfterMaterialAcquisitionMaximum" abstract="false" name="DebtInstrumentCovenantConsolidatedSecuredNetLeverageRatioAfterMaterialAcquisitionMaximum" nillable="true" xbrli:periodType="instant" substitutionGroup="xbrli:item" type="xbrli:pureItemType"/>
  <xs:element id="uctt_DebtInstrumentCovenantCashInterestCoverageRatioMinimum" abstract="false" name="DebtInstrumentCovenantCashInterestCoverageRatioMinimum" nillable="true" xbrli:periodType="instant" substitutionGroup="xbrli:item" type="xbrli:pureItemType"/>
  <xs:element id="uctt_PercentageOfUndrawnAndUnexpiredAmountOfLetterOfCreditAsFrontingFee" abstract="false" name="PercentageOfUndrawnAndUnexpiredAmountOfLetterOfCreditAsFrontingFee" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:percentItemType"/>
  <xs:element id="uctt_LineOfCreditFacilityAmountUtilizedForOutstandingBankGuarantees" abstract="false" name="LineOfCreditFacilityAmountUtilizedForOutstandingBankGuarantees" nillable="true" xbrli:periodType="duration" xbrli:balance="credit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="uctt_DebtInstrumentConvertibleTermsOfConversionAxis" abstract="true" name="DebtInstrumentConvertibleTermsOfConversionAxis" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrldt:dimensionItem" type="xbrli:stringItemType"/>
  <xs:element id="uctt_DebtInstrumentConvertibleTermsOfConversionDomain" abstract="true" name="DebtInstrumentConvertibleTermsOfConversionDomain" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="uctt_DebtInstrumentConvertibleTermOneMember" abstract="true" name="DebtInstrumentConvertibleTermOneMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="uctt_DebtInstrumentConvertibleTermTwoMember" abstract="true" name="DebtInstrumentConvertibleTermTwoMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="uctt_DebtInstrumentOptionToPurchaseAdditionalDebtThroughPrivateOffering" abstract="false" name="DebtInstrumentOptionToPurchaseAdditionalDebtThroughPrivateOffering" nillable="true" xbrli:periodType="instant" xbrli:balance="credit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="uctt_DebtInstrumentPremiumOnConversionPriceInRelationToClosingPrice" abstract="false" name="DebtInstrumentPremiumOnConversionPriceInRelationToClosingPrice" nillable="true" xbrli:periodType="instant" substitutionGroup="xbrli:item" type="dtr-types:percentItemType"/>
  <xs:element id="uctt_SharePriceOfCommonStockWithConversionPremium" abstract="false" name="SharePriceOfCommonStockWithConversionPremium" nillable="true" xbrli:periodType="instant" substitutionGroup="xbrli:item" type="dtr-types:perShareItemType"/>
  <xs:element id="uctt_DebtInstrumentConvertibleInitialCapPrice" abstract="false" name="DebtInstrumentConvertibleInitialCapPrice" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:perShareItemType"/>
  <xs:element id="uctt_EffectiveIncomeTaxRateReconciliationChangeInOwnershipOfForeignSubsidiariesAmount" abstract="false" name="EffectiveIncomeTaxRateReconciliationChangeInOwnershipOfForeignSubsidiariesAmount" nillable="true" xbrli:periodType="duration" xbrli:balance="debit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="uctt_DefinedBenefitPlanExpectedFutureBenefitPaymentAfterYearFour" abstract="false" name="DefinedBenefitPlanExpectedFutureBenefitPaymentAfterYearFour" nillable="true" xbrli:periodType="instant" xbrli:balance="credit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="uctt_DefinedBenefitPlanExpectedFutureBenefitPayments" abstract="false" name="DefinedBenefitPlanExpectedFutureBenefitPayments" nillable="true" xbrli:periodType="instant" xbrli:balance="credit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="uctt_EmployeesMember" abstract="true" name="EmployeesMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="uctt_EmployeeStockPurchasePlanMember" abstract="true" name="EmployeeStockPurchasePlanMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="uctt_ShareBasedCompensationArrangementByShareBasedPaymentAwardOtherThanOptionsEquityUnitsAcquiredPurchasePrice" abstract="false" name="ShareBasedCompensationArrangementByShareBasedPaymentAwardOtherThanOptionsEquityUnitsAcquiredPurchasePrice" nillable="true" xbrli:periodType="duration" xbrli:balance="credit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="uctt_ShareBasedCompensationArrangementByShareBasedPaymentAwardAwardVestingPeriodFromDateOfGrant" abstract="false" name="ShareBasedCompensationArrangementByShareBasedPaymentAwardAwardVestingPeriodFromDateOfGrant" nillable="true" xbrli:periodType="instant" substitutionGroup="xbrli:item" type="xbrli:durationItemType"/>
  <xs:element id="uctt_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsGrantsInPeriodFairValue" abstract="false" name="ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsGrantsInPeriodFairValue" nillable="true" xbrli:periodType="instant" xbrli:balance="debit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="uctt_ShareBasedCompensationArrangementByShareBasedPaymentAwardPerformanceObjectivePeriod" abstract="false" name="ShareBasedCompensationArrangementByShareBasedPaymentAwardPerformanceObjectivePeriod" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="xbrli:durationItemType"/>
  <xs:element id="uctt_ShareBasedCompensationArrangementByShareBasedPaymentAwardMaximumPayoutCapPercentage" abstract="false" name="ShareBasedCompensationArrangementByShareBasedPaymentAwardMaximumPayoutCapPercentage" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:percentItemType"/>
  <xs:element id="uctt_RestrictedStockUnitsPerformanceStockUnitsAndRestrictedStockAwardsMember" abstract="true" name="RestrictedStockUnitsPerformanceStockUnitsAndRestrictedStockAwardsMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="uctt_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsVestedAndExpectedToVestOutstandingNumber" abstract="false" name="ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsVestedAndExpectedToVestOutstandingNumber" nillable="true" xbrli:periodType="instant" substitutionGroup="xbrli:item" type="xbrli:sharesItemType"/>
  <xs:element id="uctt_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsVestedAndExpectedToVestAggregateIntrinsicValue" abstract="false" name="ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsVestedAndExpectedToVestAggregateIntrinsicValue" nillable="true" xbrli:periodType="instant" xbrli:balance="debit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="uctt_TwoCustomersMember" abstract="true" name="TwoCustomersMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="uctt_OneCustomerMember" abstract="true" name="OneCustomerMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="uctt_RevenueRecognitionCustomerPaymentTerms" abstract="false" name="RevenueRecognitionCustomerPaymentTerms" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="xbrli:durationItemType"/>
  <xs:element id="uctt_OtherGeographicalAreasMember" abstract="true" name="OtherGeographicalAreasMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="uctt_LamResearchCorporationMember" abstract="true" name="LamResearchCorporationMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="uctt_AppliedMaterialsIncMember" abstract="true" name="AppliedMaterialsIncMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="uctt_TotalCustomerMember" abstract="true" name="TotalCustomerMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="uctt_EarningsPerShareBasicAndDilutedEPSAbstract" abstract="true" name="EarningsPerShareBasicAndDilutedEPSAbstract" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="xbrli:stringItemType"/>
  <xs:element id="uctt_OtherForeignCountriesMember" abstract="true" name="OtherForeignCountriesMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="uctt_ExpendituresForSegmentAssetsAbstract" abstract="true" name="ExpendituresForSegmentAssetsAbstract" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="xbrli:stringItemType"/>
  <xs:element id="uctt_DepreciationDepletionAndAmortizationAdjusted" abstract="false" name="DepreciationDepletionAndAmortizationAdjusted" nillable="true" xbrli:periodType="duration" xbrli:balance="debit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="uctt_ClarenceGrangerMember" abstract="true" name="ClarenceGrangerMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
</xs:schema>
