Marking techniques for identifying integrated circuit parts at the time of testing
First Claim
1. The method of marking and subsequently identifying each one of a large group of IC parts comprising semiconductor chips formed with integrated circuitry designed for a specific functional purpose, such marking and identifying being carried out to enable part-identified tests to be performed on the functioning of the integrated circuitry of each part, said method comprising the steps of:
- forming on each chip at least one circuit element additional to said integrated circuitry;
trimming a parameter of each said additional circuit element while making measurements of an electrical value affected by said parameter;
said trimming being carried out so as to provide for each said additional circuit element an electrical value which is unique to the corresponding part;
conducting said tests to obtain a series of test data for said parts respectively;
determining said trimmed electrical values for each of the tested parts; and
storing said series of test data respectively in association with a parameter-value-generated identification of the corresponding part, thereby to permit analyses of the test data to be made and associated with the tested part respectively.
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Abstract
A technique for "marking" integrated-circuit (IC) chips so that, when large lots of the chips are drift-tested at different temperatues, each chip can be identified positively so as to be associated with the test data accumulated for the particular chip. The technique includes forming additional resistors on each IC chip with the resistors connected in series and to a voltage supply. The resistors are timmed at the wafer stage to produce at nodal points between the resistors voltages having magnitudes which uniquely identify each particular chip, thereby to permit part-identified tests to be performed after the chips have been packaged as parts ready for shipment.
65 Citations
10 Claims
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1. The method of marking and subsequently identifying each one of a large group of IC parts comprising semiconductor chips formed with integrated circuitry designed for a specific functional purpose, such marking and identifying being carried out to enable part-identified tests to be performed on the functioning of the integrated circuitry of each part, said method comprising the steps of:
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forming on each chip at least one circuit element additional to said integrated circuitry; trimming a parameter of each said additional circuit element while making measurements of an electrical value affected by said parameter; said trimming being carried out so as to provide for each said additional circuit element an electrical value which is unique to the corresponding part; conducting said tests to obtain a series of test data for said parts respectively; determining said trimmed electrical values for each of the tested parts; and storing said series of test data respectively in association with a parameter-value-generated identification of the corresponding part, thereby to permit analyses of the test data to be made and associated with the tested part respectively. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10)
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Specification