JPH0797129B2 - LSI test system - Google Patents

Description

TECHNICAL FIELD The present invention relates to an LSI test system for determining the quality of an LSI, and more particularly to an LSI test system capable of high-speed measurement.

<Prior Art> An LSI test system applies a signal to an LSI to be measured and measures an output of the LSI to be measured to judge whether the LSI is good or bad. Generally, a plurality of tests are required to judge the quality of the LSI, and these tests are continuously performed serially. FIG. 4 shows a block diagram of such an LSI test system. In FIG. 4, reference numeral 2 is a measuring unit, which is controlled by the controller 1. Each measuring section 2 creates a signal for a test based on the setting of the controller 1 and outputs it to the LSI under test 3, and also measures the output of the LSI under test 3 and transfers it to the controller 1. The controller 1 judges the quality of the LSI under test 3 based on the data transferred from the measuring section 2.

Figure 5 shows the test procedure. In FIG. 5, (A)
Is a test program and is composed of a plurality of subprograms. Each subprogram corresponds to one test, and is composed of four parts, that is, a test number definition (designation), a setting description, a measurement description, and a judgment description, and these are executed in order. (B) and (C) are time charts showing the operations of the controller 1 and the measuring unit 2 in the i-th program. With the definition of the test number, the controller 1 operates for A _i time. Controller 1 in description of setting
_Operates for B _i time, and the measuring unit 2 operates for C _i time. In the measurement description, the measuring unit 2 operates for D _i time and the controller 1 operates for E _i time. Further, in the determination description, the controller 1 operates for F _i time. Therefore, the total execution time of the i-th subprogram
T _i becomes T _i = A _i + B _i + C _i + D _i + E _i + F _i .

In such an LSI test system, the controller 1 and the measuring unit 2 do not operate at the same time, so the waiting time becomes long and the test takes a long time. Therefore, the test time may be shortened by changing the description of the test program so that the controller 1 and the measuring unit 2 operate in parallel.

<Problems to be Solved by the Invention> However, the processing method as shown in FIG. 5 has a problem that the test requires a long time and a long waiting time is not efficient.

Further, in the processing method in which the test program is changed and the controller 1 and the measuring unit 2 are operated in parallel, it is difficult to create the program because it is necessary to be aware of the parallel operation when writing the test program. Since the programs are mixed, there is also a problem that the visibility of the programs deteriorates.

<Object of the Invention> An object of the present invention is to provide an LSI test system in which a program can be easily created, the visibility of the program is not deteriorated, and high-speed processing is possible.

<Means for Solving the Problems> In order to solve the above problems, in the present invention, in an LSI test system that serially executes a plurality of tests, information for measurement is transferred from a controller to each measurement unit, and An LSI test system for determining the quality of an LSI based on a signal from the LSI under test transferred from a measuring unit, wherein test number information for designating a test number executed by this controller and its test The position in the test program of the statement of the judgment process in step 1 is stored in a table, and the controller refers to the table to define the test number of the previous test and the judgment process while the measuring unit is processing. It is the one that is to be executed.

<Operation> By storing the position of the statement executed by the controller in the table, it is possible to enable parallel operation even with a test program created without being aware of parallel operation.

<Embodiment> FIG. 1 shows a block diagram of an embodiment of an LSI test system according to the present invention. In FIG. 1, reference numeral 10 is a controller, which controls the entire LSI test system. 11
Is a memory in which a test program in which a test procedure is described is stored. 12 is a measuring unit. In this embodiment, it is composed of two measuring units. Each measuring unit 12 is composed of a module controller 13 and a measuring module 14. The module controller 13 drives the measurement module 14 according to the measurement conditions sent from the controller. The measurement module 14 corresponds to a measuring instrument,
The voltage, current, frequency, etc. signals are output to the LSI under test 3, the values of the voltage, current, frequency, etc. at the specified pins of the LSI under test 3 are measured, and the data is stored in the module controller
Transfer to. A standard bus 15 connects the controller 10, the memory 11 and the measuring unit 12. The controller 10 reads the test program of the memory 11 via this standard bus 15 and also transfers the measurement condition data to the module controller 13. Further, the module controller 13 transfers the data of the LSI 3 under measurement collected by the measurement module 14 to the controller 10 via the standard bus 15. Reference numeral 16 is a dedicated bus, which connects the controller 10 and each measurement unit 12. After transferring the measurement condition to each module controller 13, the controller 10 transfers a dedicated code for simultaneously starting the test sequence to each module controller 13 via this dedicated bus and interrupts it.

Next, the operation of this embodiment will be described with reference to FIG. FIG. 2A illustrates the operation of one subprogram. Each subprogram is composed of four processes of test number definition (designation), setting process, measurement process, and determination process, and these processes are executed sequentially. The definition of the test number is a numerical value starting from 1, for example, for specifying the subprogram, and is recognized by the controller 10. The setting process is divided into two processes, a process performed by the controller 10 and a process performed by the module controller 13.
The controller 10 sets measurement conditions and the like in the module controller 13, and the module controller 13 controls the measurement module 14 based on these conditions. The measurement process is a process of giving a signal to the LSI to be measured and collecting its output.
All the measuring units 12 are made to operate simultaneously. The determination process is a process performed by the controller 10, and evaluates the collected data to determine the test result. The following restrictions exist between these processes due to the processing flow.

(1) The setting process performed by the controller 10 must be performed before the setting process and the measurement process performed by the module controller 13.

(2) Judgment processing must be performed after test number definition, setting processing, and measurement processing.

Here, it is necessary to define (designate) the test number before the determination process, because the test number and the measurement result are saved when the measured LSI is determined to be defective as a result of the determination process. is there. The cause of the defective product is analyzed based on the stored data. In performing this analysis, the contents of the test are necessary, and the test number tells which subprogram the measurement result was obtained from. In short, the definition (designation) of the test number is necessary to specify the test number during the determination process, and must be performed immediately before the determination process at the latest.

(3) The setting process performed by the controller 10 must be performed after the measurement process of the immediately preceding subprogram.

Due to these constraints, conventionally, the controller 10 and the measuring unit 12 operate alternately as shown in FIG. 5, and when one is operating, the other waits.
In addition, due to this constraint condition, it is difficult to create a program that operates in parallel. In this embodiment, the controller 10 and the module controller 13 are driven according to the time chart shown in FIG. That is, when the processing of the i-th subprogram is started at time T ₁ , the controller 10 executes the setting processing. When the setting process ends at time T ₂ , the module controller 13 starts the setting process, and then starts the measurement process at time T ₃ . On the other hand, the controller 10 defines the test number in the previous (i-1) subprogram from time T _2, waits until time T _3, and executes the previous determination process. Time T _{4 when the} module controller 13 measurement process or controller 10 determination process ends
Then, the processing of the subprogram i ends. Therefore, the processing time required for the sub-program i is the sum of the setting processing time (T ₂ −T ₁ ) of the controller 10 and the total setting processing and measurement processing time (T ₄ −T ₂ ) of the module controller 13. The processing time can be shortened by the time required for the definition of the test number and the determination processing. Incidentally, since the measurement processing time is usually long, a waiting time occurs on the controller side as shown in FIG. 2B. However, the test number definition and judgment processing time of the controller 10 is set by the module controller 13. If the time is longer than the measurement processing time, the module controller 13 waits, and the processing time is shortened by the time of the setting processing and the measurement processing of the module controller 13.

In the present invention, the parallel processing shown in the time chart of FIG. 2B can be realized without changing the configuration of the test program. FIG. 3 shows a configuration therefor. FIG. 3 shows the structure of a table held by the controller 10, in which the definition of the test number of each subprogram and the position information in the memory 11 of the statement of the judgment processing are stored. These pieces of position information are stored in the table in order from the first subprogram in this order.
Normally, in the LSI test system, each test item is described in a high-level language based on a general-purpose programming language, and stored in the memory 11 in an executable form such as an object code. The controller 10 sequentially reads out the programs stored in the memory 11 and executes them. At that time, when the setting process is completed, the controller 10 refers to the table shown in FIG. 3 to identify the position of the statement of the test number definition of the previous one and the statement of the judgment process, and the corresponding position from the memory 11 Read and execute the statement that you want. By doing this, even if a program created without paying attention to parallel processing
Parallel processing as shown in Figure (B) can be executed,
The test time can be shortened.

In the table, the position of the statement of the test number definition is written at the beginning of each subprogram, and the position of the statement of the determination process is written at the end of the subprogram. Therefore, although the time for writing the positional information of these statements is actually required, it can be ignored compared to other processing times.

Also, in the actual program, the number of processes shown in FIG. 2 (A) is different. For example, there are many test number definition and determination processes, but in this case, since the positional information of the statements of these processes remains in the table, they are not executed and left.

In addition, normal testing will increase the time of the measurement process and therefore the latency of the controller 10. By using this waiting time, it is possible to operate as a module controller of the measuring unit that does not execute the measuring process. Further, when various data processing other than the determination processing is requested, conventionally, all the tests are performed after completion of the tests. However, if the data is processed during this waiting time, the test time can be further shortened.

<Effects of the Invention> As specifically described above based on the embodiments, in the present invention, the test number information for designating the test number and the position information of the statement of the determination process are held in the table, and the measurement is performed. While the department is performing the setting process and the measurement process, the test number of the previous test is designated and the measurement process is performed. Therefore, the controller and the module controller can be operated in parallel, and the time required for the test can be shortened. In particular, the LSI test usually consists of a test consisting of several hundreds of subprograms, so the effect of reducing the processing time is great.

In addition, since the test number information for specifying the test number and the position information of the statement of the judgment process are stored in the table, the parallel processing is possible even for the program created without paying attention to the parallel processing. Is also easy to create, and its visibility is not deteriorated.

[Brief description of drawings]

FIG. 1 is a configuration diagram showing an embodiment of an LSI test system according to the present invention, FIG. 2 is a diagram showing a processing procedure, FIG. 3 is a diagram showing a configuration of a table, and FIG. 4 is a conventional LSI test. FIG. 5 is a configuration diagram of the system, and FIG. 5 is a diagram showing the procedure of the processing. 3 ... LSI to be measured, 10 ... Controller, 11 ... Memory, 12 ... Measuring unit, 13 ... Module controller, 14
…… Measurement module, 15 …… Standard bus, 16 …… Special bus.

Claims (1)

[Claims] 1. An LSI test system for serially executing a test program comprising a plurality of subprograms, each of which applies a signal from a measuring section to an LSI to be measured, measures an output from the LSI to be measured, and judges pass / fail of the output. A controller for transferring information of a subprogram for measuring the LSI to be measured to the measuring unit, and determining the quality of the LSI based on an output from the LSI to be measured transferred from the measuring unit, The controller stores the test number specifying the subprogram executed by this controller and the position of the statement of the judgment processing in the table, and the controller refers to the table while the measuring section is performing the processing, and the controller refers to the previous subprogram. An LSI test system characterized in that a test number for specifying a program is designated and a previous determination process is executed.