<SEC-DOCUMENT>0000056978-20-000167.txt : 20201215
<SEC-HEADER>0000056978-20-000167.hdr.sgml : 20201215
<ACCEPTANCE-DATETIME>20201215082352
ACCESSION NUMBER:		0000056978-20-000167
CONFORMED SUBMISSION TYPE:	4
PUBLIC DOCUMENT COUNT:		1
CONFORMED PERIOD OF REPORT:	20201211
FILED AS OF DATE:		20201215
DATE AS OF CHANGE:		20201215

REPORTING-OWNER:	

	OWNER DATA:	
		COMPANY CONFORMED NAME:			Chong Chan Pin
		CENTRAL INDEX KEY:			0001692400

	FILING VALUES:
		FORM TYPE:		4
		SEC ACT:		1934 Act
		SEC FILE NUMBER:	000-00121
		FILM NUMBER:		201388251

	MAIL ADDRESS:	
		STREET 1:		23A SERANGOON NORTH AVENUE 5
		STREET 2:		#01-01
		CITY:			SINGAPORE
		STATE:			U0
		ZIP:			554369

ISSUER:		

	COMPANY DATA:	
		COMPANY CONFORMED NAME:			KULICKE & SOFFA INDUSTRIES INC
		CENTRAL INDEX KEY:			0000056978
		STANDARD INDUSTRIAL CLASSIFICATION:	SEMICONDUCTORS & RELATED DEVICES [3674]
		IRS NUMBER:				231498399
		STATE OF INCORPORATION:			PA
		FISCAL YEAR END:			1003

	BUSINESS ADDRESS:	
		STREET 1:		23A SERANGOON NORTH AVENUE 5, #01-01
		CITY:			SINGAPORE
		STATE:			U0
		ZIP:			554369
		BUSINESS PHONE:		2157846000

	MAIL ADDRESS:	
		STREET 1:		23A SERANGOON NORTH AVENUE 5, #01-01
		CITY:			SINGAPORE
		STATE:			U0
		ZIP:			554369
</SEC-HEADER>
<DOCUMENT>
<TYPE>4
<SEQUENCE>1
<FILENAME>wf-form4_160803861966957.xml
<DESCRIPTION>FORM 4
<TEXT>
<XML>
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<ownershipDocument>

    <schemaVersion>X0306</schemaVersion>

    <documentType>4</documentType>

    <periodOfReport>2020-12-11</periodOfReport>

    <notSubjectToSection16>0</notSubjectToSection16>

    <issuer>
        <issuerCik>0000056978</issuerCik>
        <issuerName>KULICKE &amp; SOFFA INDUSTRIES INC</issuerName>
        <issuerTradingSymbol>KLIC</issuerTradingSymbol>
    </issuer>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001692400</rptOwnerCik>
            <rptOwnerName>Chong Chan Pin</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>23A SERANGOON NORTH AVENUE 5 #01-01</rptOwnerStreet1>
            <rptOwnerStreet2></rptOwnerStreet2>
            <rptOwnerCity>SINGAPORE</rptOwnerCity>
            <rptOwnerState>U0</rptOwnerState>
            <rptOwnerZipCode>554369</rptOwnerZipCode>
            <rptOwnerStateDescription>SINGAPORE</rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>0</isDirector>
            <isOfficer>1</isOfficer>
            <isTenPercentOwner>0</isTenPercentOwner>
            <isOther>0</isOther>
            <officerTitle>Executive Vice President</officerTitle>
            <otherText></otherText>
        </reportingOwnerRelationship>
    </reportingOwner>

    <nonDerivativeTable>
        <nonDerivativeTransaction>
            <securityTitle>
                <value>Common Stock</value>
            </securityTitle>
            <transactionDate>
                <value>2020-12-11</value>
            </transactionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>M</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
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            <transactionAmounts>
                <transactionShares>
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                    <footnoteId id="F1"/>
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                <transactionPricePerShare>
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                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
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                </transactionAcquiredDisposedCode>
            </transactionAmounts>
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                <sharesOwnedFollowingTransaction>
                    <value>104558</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
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        <nonDerivativeTransaction>
            <securityTitle>
                <value>Common Stock</value>
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                </transactionAcquiredDisposedCode>
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            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
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                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
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                </directOrIndirectOwnership>
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        </nonDerivativeTransaction>
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    <derivativeTable>
        <derivativeTransaction>
            <securityTitle>
                <value>Performance Share Units</value>
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            <transactionDate>
                <value>2020-12-11</value>
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                <transactionPricePerShare>
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            <expirationDate>
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                <underlyingSecurityShares>
                    <value>5421.0</value>
                </underlyingSecurityShares>
            </underlyingSecurity>
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                <sharesOwnedFollowingTransaction>
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                </sharesOwnedFollowingTransaction>
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            <securityTitle>
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            </securityTitle>
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            </underlyingSecurity>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>0</value>
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                </directOrIndirectOwnership>
            </ownershipNature>
        </derivativeTransaction>
    </derivativeTable>

    <footnotes>
        <footnote id="F1">Performance Share Units (PSUs) awarded December 11, 2017 achieved a 95% payout based on total shareholder return (TSR) relative to a peer group.  The peer group consisted of the companies of the GICS 45301020 (Semiconductors) not including companies traded on the Pink Sheets LLC Exchange as of the beginning of Performance Period with relative TSR measured over a three year period.  The payout was certified and shares issued on December 11, 2020.  Each PSU is convertible into one share of common stock.</footnote>
        <footnote id="F2">Performance Share Units (PSUs) awarded December 11, 2017 achieved a 17% payout based on the greater of absolute revenue growth or relative revenue growth against two performance peers for each year of the three-year performance period.  The payout was certified and the shares issued on December 11, 2020.  Each PSU is convertible into one share of common stock.</footnote>
    </footnotes>

    <remarks></remarks>

    <ownerSignature>
        <signatureName>Susan L. Waters, Attorney-in-Fact for Chan Pin Chong</signatureName>
        <signatureDate>2020-12-15</signatureDate>
    </ownerSignature>
</ownershipDocument>
</XML>
</TEXT>
</DOCUMENT>
</SEC-DOCUMENT>
