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Semiconductor Chip Testing

IP.com Disclosure Number: IPCOM000087036D
Original Publication Date: 1976-Dec-01
Included in the Prior Art Database: 2005-Mar-03
Document File: 2 page(s) / 13K

Publishing Venue

IBM

Related People

Hanna, SD: AUTHOR

Abstract

DC testing techniques can detect and identify AC failures in semiconductor logic (switching) circuit chips. AC failures are not the only defects that can be detected by DC testing techniques. Internal node-to-node shorts and untested stuck fault failures can also be detected. This DC technique can also be used for analysis of circuit modules whether or not there is information as to failure locations in such modules. The principle of the tests is that AC defects result in more-or-less current being drawn from the most positive voltage supply than good modules or chips for a specific input data pattern, thereby identifying AC abnormal circuits.

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Semiconductor Chip Testing

DC testing techniques can detect and identify AC failures in semiconductor logic (switching) circuit chips. AC failures are not the only defects that can be detected by DC testing techniques. Internal node-to-node shorts and untested stuck fault failures can also be detected. This DC technique can also be used for analysis of circuit modules whether or not there is information as to failure locations in such modules. The principle of the tests is that AC defects result in more-or-less current being drawn from the most positive voltage supply than good modules or chips for a specific input data pattern, thereby identifying AC abnormal circuits.

First, for each module or chip-type, current drain magnitude is established for a variety of input patterns. This test is termed a power supply current drain test (PSD).

PSD-generated current magnitudes are a function of:.
1. Internal on or off pattern of the logic circuits (this pattern

being a function of the input pattern).
2. Resistor value and, to a lesser extent, Vbe, Vbc,Vsch and Vce.

The PSD current magnitude is similar on identical modules which are tested to the same input pattern. The main difference in PSD current values between good modules is due to resistor value variations.

For different input patterns (test control signal connections to the chip), PSD current will vary; this variation is termed delta PSD. By specifying limits on delta PSD with respect to input patterns and assuming that resistor tracking within a chip is very tight, defects of the type discussed above can be detected. To test using a nonzero delta PSD, a resistor scaling factor should be employed.

Several method...