JPH036037A - Semiconductor testing apparatus - Google Patents

Abstract

PURPOSE:To judge process capacity of a production line by adding a control apparatus which includes the following: a storage part to which a measured data is input; a computation part to which this stored data is input and which computes a process capacity index corresponding to a preset standard value. CONSTITUTION:When a test start signal is sent out from a probing apparatus 2, measuring conditions are transferred from a CPU 6 to a measuring part 7 and a power supply 8 used to apply a bias; a test signal ST is supplied to a first chip under test of a wafer 3; its electrical characteristic is tested. This measured data SD is transferred to a control apparatus 5 from the CPU 6; a process capacity index of a production line regarding a standard width for each item is computed at a computation part 10 on the basis of the measured data SD which has been stored in a storage part 9. When its result cannot satisfy the preset control standard, a control signal SC is supplied to the probing apparatus 2 from the computation part 10; a test of the chip on the wafer 3 is stopped automatically. Thereby, abnormality of a lot can be predicted; change in the production line can be predicted; it is possible to prevent a drop in the yield and to predict and maintain the quality.

Description

[Detailed description of the invention] [Industrial application field] The present invention relates to a semiconductor testing device.

[Conventional technology]

With the recent increase in testing in the manufacturing process of semiconductor devices, improving the efficiency has become important.

FIG. 2 is a block diagram of an example of a conventional semiconductor testing device.

Semiconductor test equipment 11. A measuring section 7 applies a test signal ST to the chips of the wafer under test 3 placed on the wafer stage 4 of the blowing device 2 and inputs measurement data SD, and C' compares and calculates the data SD and standard values. P.U.
6, and an input/output device 12 for transmitting and receiving an input/output signal SIO.

In this case, the chip test is performed by automatically sequentially supplying test signals ST using a test program created based on preset test conditions and standards, and measuring data SD obtained from the chips on wafer 3 according to the standards. It automatically judged whether the chip was good or bad by comparing it with the value.

In addition, quality control of manufactured rods was separately performed by analyzing sampled measurement data SD.

3 and 4 are a characteristic distribution diagram and a rod control diagram for explaining quality control of semiconductor devices.

The process capability index Cp is the first quality control criterion that indicates whether the manufacturing line is producing products that meet specifications.
It is expressed by the formula.

Generally, it is said that the process capability is sufficient if the standard width T is 8 times or more the standard deviation δ.

The process capability index Cp at that time is 1.33, and the smaller the value, the less preferable it is.

Cp = T/ < 6δP)...(1) Also, the process capability index CPK is a judgment criterion used to comprehensively evaluate the process average and variation 6δP, and is calculated using equation (2) and (
3) Expressed by the formula.

CPK=C(1-K)xT)/6δP...
(2) K= (IM-xi)/ (T/2>=13)
In the case of the characteristic distribution diagram shown in No. 3, the process capability index CP is 1
．． 86. Cp is 0.7, which indicates that cpx is bad, the rod is defective, and the manufacturing line is bad.

Furthermore, as shown in Fig. 4, the ninth manufactured rod L9' is a defective rod, but the broken line of the rod average value Since there is, rod L6. An alarm was being issued at L7 indicating a tendency for production rod abnormalities to occur.

In these cases, the related production lines, including testing, will be temporarily suspended and the production lines will be restarted after quality control measures have been taken.

[Problem to be solved by the invention]

The conventional semiconductor test equipment described above separately tests whether the measured values of the semiconductor under test meet the specifications and performs quality control of the rod under test. Because the process capability of the process is not fully understood, if the characteristic values are within the standard values, changes in the characteristics within the standard due to changes in the production line are not noticed, countermeasures are delayed, and the problem is caused by the sudden occurrence of a large number of defects. This had the disadvantage of causing a decrease in yield.

An object of the present invention is to provide a semiconductor testing device that can determine the process capability of a manufacturing line.

[Means to solve the problem]

The semiconductor testing apparatus of the present invention includes a test circuit section that sequentially connects semiconductor devices under test of continuous manufacturing rods to measure electrical characteristics, and the semiconductor test device outputs the semiconductor devices under test from the test circuit section. A control device is added that includes a storage unit that inputs and stores measurement data of the storage unit, and a calculation unit that inputs the data stored in the storage unit and calculates a process capability index of the manufacturing line in accordance with preset standard values. It is composed of

〔Example〕

Next, the present invention will be explained with reference to the drawings.

FIG. 1 is a block diagram of one embodiment of the present invention.

The semiconductor test device 11 receives measurement data sD from the test circuit section 1 instead of the input/output device 12 in FIG. 2 and sends a control signal S to the probing device 2. The difference is that a control device 5 is added to supply the conventional semiconductor test equipment 11
, is the same as .

The control device 5 includes a storage unit that stores measurement data SD;
It has an arithmetic unit 10 that calculates manufacturing line process capability indices CP and CPK in accordance with a preset standard value range T.

Next, the operation of the device 11 will be explained.

First, the wafer 3 to be tested is automatically placed on the wafer stage 4 of the blowing device 2 .

Next, when a test start signal is issued from the blowing device 2, the measurement conditions are transferred from the CPU 6 to the measurement unit 7 and the power supply 8 that applies bias, and the test signal S↑ is supplied to the first chip under test on the wafer 4. and its electrical properties are tested.

At this time, the tested measurement data sD is transferred from the CPU 6 to the control device 5.

The CPU 6 sends a pass/fail signal of the test result to the blowing device 2.
The probe of the probing device 2 transfers the connection to the next chip under test.

The measurement data So is transferred to the control device 5 as many times as necessary for sampling.

In the control device 5, the measurement data SD stored in the storage section 9
Based on this, the calculation unit 10 calculates the process capability indexes Cp and Cp of the production line for each standard width using equations (1) and (2).

If the result does not satisfy the preset management criteria, a control signal SC is sent from the calculation unit] 20 to the brobing device 2.
is supplied to automatically stop testing the chips on wafer 3.

At the same time, the control device 5 issues an alarm to notify the rod of abnormality.

Therefore, as shown in Figure 3 above, even for rods for which testing was continued because there were few standard defects, an alarm is automatically issued when a CPX defect is determined, resulting in a large number of rod defects. This has the effect of allowing the test to be stopped preemptively.

Moreover, if past rod data is sequentially stored in the storage unit 9 of FIG. 1 and determinations as shown in FIG. 4 are made, rod trends can be managed.

In the above-described embodiments, the present invention is applied to a chip of a wafer under test as a semiconductor device under test, but it may also be applied to a semiconductor device subjected to a characteristic selection test as a test object.

〔Effect of the invention〕

As explained above, the present invention adds a control device having a memory/calculation unit to extract measurement data of a semiconductor device under test, and stores the defective rate of rods and the process capability index of the manufacturing line in a storage device. Since it is possible to carry out trend management based on past measured values of rods, it is possible to predict rod abnormalities and fluctuations in the production line, thereby making it possible to prevent yield decline and perform quality predictive maintenance.

[Brief explanation of drawings]

FIG. 1 is a block diagram of an embodiment of the present invention, FIG. 2 is a block diagram of an example of a conventional semiconductor testing device, and FIGS.
The figures are a characteristic distribution diagram and a rod control diagram for explaining quality control of semiconductor devices. 1... Test circuit section, 2... Blobbing device, 3...
...Wafer under test, 4...Wafer stage, 5.
・・Control device, 6・CPU, 7・Measurement unit, 9・
...Storage unit, 10...Calculation unit, SC...Control signal,
SO...Measurement data, 8 pieces...Test signal.

Claims (1)

[Claims] In a semiconductor testing device having a test circuit section that sequentially connects semiconductor devices under test of continuous production rods and measures electrical characteristics, inputting and storing measurement data of the semiconductor device under test output from the test circuit section. A semiconductor testing device comprising: a storage section for inputting data stored in the storage section; and an arithmetic section for inputting data stored in the storage section and calculating a process capability index of a production line in accordance with preset standard values. .