JPS62126368A - Lsi testing system - Google Patents

Abstract

PURPOSE:To make it possible to simultaneously carry out the functional test of LSI and the measurement of a DC characteristic, by changing the values of low level and high level threshold value voltages according to the judge result of the functional test. CONSTITUTION:Prior to a functional test, a test pattern is set to a pattern memory 1 and the information of the input and output pins of LSI to be tested is set to a pin information register 2 and information necessary for the generation of an input wave form is set to an input signal timing generator 5 and the generation timing of an output judge strobe is set to an output judging timing generator 8. Next, high and low level threshold values and change voltage during testing are set to an output judging threshold value voltage setting part 4. The functional test is carried out under this condition and repeated until comes to fail. The value obtained by subtracting change voltage from the threshold value at the time of fail comes to the DC characteristic of LSI to be tested.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Application of the Invention] The present invention relates to an LSI test method in which a threshold voltage setting value for output determination is made variable according to the results of a functional test.

[Background of the invention]

In the conventional LSI test method, ■oL,
sr:r, Vott, sx:r (LOW level, H
Since it was necessary to uniquely determine the value of the IGH level threshold voltage, for example, the LSI output '4 voltage Vor, , Van
When performing measurements etc. at the same time as functional tests, ■or,,s
r:r VoH, sgr.

The disadvantage was that the values had to be reset.

In Japanese Patent Application Laid-Open No. 55-27907, VOL, 5
ETvoII discusses the output determination strobe with SET fixed.

[Purpose of the invention]

The purpose of the present invention is to
5tar, Van, sr; change the value of r, LS
The purpose of this invention is to provide an LSI test method that can simultaneously perform a functional test of I and a measurement of @prevalence (Vot, VoH).

[Summary of the invention]

The feature of the present invention is that the VOL,
SET, VOH, SET ノ(iwo'f conversion'l-Serukoto K L) LSI functional test and DC characteristics (■OL
, VQH) can be measured simultaneously, improving the efficiency of LSI testing.

[Embodiments of the invention]

Examples of the present invention will be described below based on (2).

FIG. 1 is a block diagram of an example of an LSI test before being tested by the LSI test method according to the present invention, FIG. 2 is a flowchart thereof, and FIG. 5 is a time chart for explaining the operation of the same embodiment. .

Here, 1 is a pattern memory that stores test patterns, and 2 is a temporary test/controller that specifies input pins and output judgment pins.
5 is a pin i information register that stores information for each bin of SI; 5 is a determination result register that stores output determination results;
4 is VOL, SET.

VO//, output judgment dose li'I for setting SET
['αα Pressure lung part 54 is an input signal timing generator that determines the waveform of the human power signal, 6 is an input signal driver that supplies input signals to the human power bin according to the input pattern, and 7 is the captured output signal level and output. 8 is an output judgment timing generator for an output judgment strobe, and 9 is an LSI under test.

First, prior to testing Function
What input waveform do you want to apply to the input pin of the input signal timing generator 5? The generation timing of the output determination strobe is set in the output determination timing generator 8 and the information necessary for generating the output determination strobe is set at 0.degree. C. (processes 21 and 22 in FIG. 2).

Next, VoL, sr:
Set rvQH, SET and the change output ttv during the test. Set () to execute the function test (process 24), and repeat until it fails (process 26, 25, 24).
). If the function test fails and the loop in Figure 2 is removed (Figure 5 B), the next vQH, SET
The value obtained by subtracting cLV from is the v of the LSI pin under test.
It becomes OH.

In addition, VOL no all fixed 1c Tsuite&X VOL
, Sli:T かT;) Repeat the functional test while subtracting cLv.

〔Effect of the invention〕

Hon'duAK1. tLrff,,v□r,,sgr,
VOH, SIf: T ノ (W' can be made variable depending on the judgment result of the function test, and the LS
DC characteristics (Vor, von
) can be measured, improving the efficiency of the first LSI exam.
Effective for measuring direct current characteristics.

[Brief explanation of drawings]

FIG. 1 is a block diagram of an LSI test device according to the A method, LSI test 1 according to an embodiment of the present invention, FIG. 2 is a flowchart thereof, and FIG. 5 is a time chart for explaining the operation of the same embodiment. 1... Pattern memory 2... Pin information register 5... Judgment result register 5... Input signal timing generator 6... Input signal driver 7... Output judgment section 8. ... Timing generator for output judgment 9 ... Tested @ LSI ~ (Patent attorney Katsutoshi Ogawa)' Part 1 Figure 2

Claims (1)

[Claims] 1. Store the test pattern in the pattern memory, and
An input pattern is applied to the input terminal of the SI, and the output waveform of the output terminal of the LSI is captured by opening the gate of the comparison comparator at the timing determined by the output judgment timing generator, and the signal level is set in advance. Is the output HIGH level threshold voltage or higher?
An LSI that performs a functional test of an LSI in which a comparison is made with an expected output value stored in the pattern memory in the comparison comparator depending on whether the output LOW level is below a threshold voltage, and pass or fail is determined based on the match or mismatch. An LSI test method, characterized in that, in a test apparatus, the values of the two-level threshold voltages are changed according to the determination result of a functional test.