JP3428713B2 - Apparatus and method for automatically determining test results - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION This invention relates to a test device (tester).
The present invention relates to an automatic test result determination apparatus and method for automatically processing a test result obtained by the above.

[0002]

2. Description of the Related Art In commercializing a semiconductor integrated circuit (IC), a trial production is usually carried out, and various kinds of predetermined electrical signals are tested in order to check whether or not the trial produced IC has a predetermined performance. The characteristics are measured by a test device (tester). After that, it is judged whether or not these measured values satisfy the standard values defined for the product. If they are satisfied, the process shifts from trial production to mass production. On the other hand, if not satisfied, after making improvements in the circuit and manufacturing for the corresponding item, the trial production, measurement and determination are performed again. The above operation is repeated until the standard value is satisfied.

FIG. 15 is a diagram for explaining a conventional test method using a tester. In FIG. 15, 21 is an IC memory which is an object to be measured, and 22 is a semiconductor integrated device for measuring the IC memory 21. The circuit test device (tester) 23 is a CRT or printer for displaying or printing the electrical characteristics of the IC memory 21 measured by the tester 22.

FIG. 16 is a diagram showing an example of a characteristic display displayed or printed by the CRT or printer 23. This figure shows two types of characteristic items as X-axis and Y-axis, and shows the relationship between them in a plane, which is called a shmoo plot. This shmoo plot makes it easy to visually grasp the quality of the product in a wide range,
Commonly used.

The Shmoo plot uses two types of characteristic items (parameters such as power supply voltage and input timing of various signals) as characteristic axes (X axis and Y axis in FIG. 16). The tester 22 changes these parameters at regular intervals (ΔX, ΔY), and under each test condition, IC
The memory 21 is tested. Then, the good / bad determination results are plotted in a matrix on the X-axis-Y-axis plane displayed on the CRT or printer 23.

As shown in FIG. 16, the range (XMIN, XMAX, YMIN, YM
AX), each MIN and each MAX
Set measurement points at intervals of (ΔX, ΔY) between and. The standard value XMIN, standard value XMAX, standard value YMIN, and standard value YMAX in FIG.
If the memory 21 indicates a region that should satisfy a predetermined standard, and the predetermined characteristics are satisfied in all of this region, this IC
The memory 21 is a good product. As the measurement results at the intersections of the set points of the X-axis and the Y-axis, if the test object moves, Pass is displayed (symbol P), and if it malfunctions, Fa
il is displayed (symbol F). In some cases, only one of the Pass display and the Fail display is displayed.

When the shmoo plot of FIG. 16 is obtained,
The measurer performs the following determination work based on this shmoo plot. (1) Is the area in which the test object operates normally (the area in which the symbol P is displayed) sufficiently wider than the predetermined area to operate (the area according to the standard value)? That is,
Whether the operation margin (margin) is large. (2) Is there any abnormal operation in the area where it should be operated? For example, is there a measurement point of F in the area to be operated? (3) Comparing the test object and the test object obtained by improving it, to what extent the characteristics were improved before and after the improvement. Based on the judgment result obtained by such work, it is judged whether or not the characteristics of the tested IC are satisfactory, and if they are, the process shifts from trial production to mass production.

[0008]

However, recent ICs
In the test, the number of items to be measured has greatly increased due to the complicated function, and there are several hundred items. In addition, in order to perform the pass / fail judgment of these ICs without bias, it is necessary to measure several tens of ICs as samples. Therefore, the number of shmoo plots to be measured for the judgment is very large. As described above, the determination of the shmoo plot is performed by the measurer, so that it may take time and a determination error may occur.

Further, in the above work (3), the shmoo plots before and after the improvement are arranged to visually compare the shapes. With this method, the outline can be obtained, but in the case of quantitative comparison, it is necessary to read the coordinates of many Pass points or Fail points, which requires a lot of time.

The present invention has been made to solve such a problem, and an object thereof is to obtain an automatic determination device and method for a test result which can accurately determine an abnormality in characteristics.

[0011]

[0012]

[0013]

An automatic test result determining apparatus according to the present invention includes storage means for storing a shmoo plot which is a test result of the electrical characteristics of a test object, and the storage means. Address generating means for generating the address of the means, and the storage means for storing the sum based on the output of the address generating means.
Reads a plurality of data of the plot, read Zhu
Based on the non-continuity in a plurality of data in Mu plot
This can be performed by determining the abnormal shape of the Kushmoo plot.
And a determination means for determining whether the shmoo plot is good or bad.

Further , automatic determination of the test result according to the present invention
The method is a test result of the electrical characteristics of the test object.
Storing a certain shmoo plot in the storage means,
The above is based on the output of the address generation means that generates the street address.
Read multiple data of Shmoo plot from storage
The multiple data in the read Shmoo plot.
Of abnormal shape of shmoo plot based on discontinuity
The quality of the shmoo plot by determining
It is something.

[0015]

[0016]

[0017]

In the present invention, the electrical characteristics of the test object
Means of storing the shmoo plot which is the test result of
Address generating means for storing the address in the storage means
Of the shmoo plot based on the output of
Number of data is read, and the read shmoo plot is in progress
Shmoo Pro based on discontinuity in multiple data
The abnormal shape of the
The quality of the packet.

[0018]

[0019]

【Example】

Example 1. FIG. 1 is a block diagram showing the structure of an automatic test result judging apparatus according to an embodiment of the present invention, and 2 is an address selecting means for generating an address corresponding to coordinates of a shmoo plot by a predetermined procedure, Reference numeral 3 is a storage means for receiving a test result (shmoo plot) from an external semiconductor integrated circuit test device (tester) and storing it. 4 is a test based on the data of the storage means 3 read by the address selection means 2. It is a determination unit that determines the quality of the target semiconductor device (IC).

FIG. 2 shows the automatic determination device 1 and the tester 2 of FIG.
It is a figure which shows the connection with 2 grade. The tester 22 performs a predetermined test on the IC 21 that is the test target, and outputs the result to the automatic determination device 1. The CRT or printer 23 displays the shmoo plot which is the test result of the tester 22 and also the judgment result of the automatic judgment device 1. The semiconductor device (IC) 21, the semiconductor integrated circuit test device (tester) 22, the CRT or the printer 23 are the same as or equivalent to those shown in the conventional example. Note that a new CRT or printer may be provided as shown by the dotted line in FIG. 2 so that only the determination result of the automatic determination device 1 is displayed.

FIG. 3 and FIG. 4 are flowcharts showing the judgment processing in the case of judging the presence or absence of the margin of the IC 21 by the shmoo plot.

Next, the operation will be described. The address selecting means 2 generates predetermined X and Y coordinates of the Shmoo plot and causes the storage means 3 to output the corresponding Y axis and X axis data. Here, it is assumed that the storage means 3 stores a shmoo plot which is a test result of the tester 22 in advance. This shmoo plot is similar to that shown in FIG. The determination unit 4 performs a predetermined process described below and outputs the determination result to the CRT or the printer 23.

Specifically, the determination is made as follows. I
The region where C should satisfy the characteristics is assumed to be the region of the rectangular PQRS shown in FIGS. 5 (a) and 5 (b). That is, it is an area from the standard value XMIN of the X axis to the standard value XMAX and from the standard value YMIN of the Y axis to the standard value YMAX. It is necessary to satisfy the characteristics for all the measurement points within the area inside the rectangular PQRS. By the way, in practice, since it is necessary to have some margin, the determination is made within the area inside the rectangle P'Q'R'S 'which is similar to the rectangle PQRS and larger (for example, about 20% larger). . If the result is Pass, this IC has good characteristics and has a predetermined margin with respect to the standard value. FIG. 5A shows an example of this case.

On the other hand, in FIG. 5 (b), the standard value XMIN
The intersection point P between the standard value YMIN and the intersection point P ′ of the margin area corresponding to the intersection point P is not included in the Pass area A2 and becomes Fail. Therefore, this IC does not have a margin with respect to the standard value and is defective. is there. From this, the rectangle P '
On the four sides of Q'R'S ', that is, the side P'parallel to the X axis
By checking whether all measurement points are Pass in Q'and side S'R ', and in side P'S' and side Q'R 'parallel to the Y-axis, this IC has a specified margin. It can be determined whether the value is satisfied. By checking whether or not all the measurement points are Pass on the four sides of the rectangle PQRS, that is, on the sides PQ and SR parallel to the X axis and on the sides PS and QR parallel to the Y axis,
It can be determined whether this IC satisfies the standard value. Since the specific determination process is the same for both the rectangle PQRS and the rectangle P'Q'R'S 'as described above, the case of the rectangle PQRS will be described as an example in the following description.

Next, the details of the above determination processing will be described with reference to FIG.
4 and the flowchart of FIG.

First, in ST1 to ST4, the standard value MIN side for the characteristic item Y (Y axis) (in the rectangle P'Q'R'S 'indicating the area including the margin, the margin standard value MIN side, and so on). Is determined. ST1 (X = standard value XMIN) Standard value XM as the initial value of the characteristic item X (X coordinate) for judgment
Set IN. ST2 (Y = standard value YMIN) The standard value YMIN is set as the initial value of the Y coordinate for determination. By the processes of ST1 and ST2, the point P in FIG. 5 is set as the initial value.

ST3 (Pass / Fail Judgment) It is judged whether the test result of the designated coordinate (for example, point P) is Pass or Fail. If Pass, proceed to ST4. On the other hand, in the case of Fail, in ST31, the determination result indicating that there is no margin on the standard value YMIN side is recorded, the process on the standard value YMIN side (side PQ in FIG. 5) is terminated, and the process proceeds to ST5.

ST4 (X = standard value XMAX?) It is checked whether the X coordinate has reached the standard value XMAX, that is, whether it has reached point Q in FIG. If the standard value XMAX has been reached, the processing on the side PQ has ended, so the process proceeds to ST5 to process the side SR next. On the other hand, if the standard value XMAX is not reached, in ST41,
Add the measurement interval ΔX on the X axis to the current X coordinate (X
= X + ΔX), the process returns to ST3 and the determination process at the next measurement point is performed. The above-mentioned processing of ST1 to ST4 is performed with the standard value X.
Repeat until it reaches MAX. As a result, the side PQ of FIG.
The determination at is completed.

Next, in ST5 to ST8, margin judgment on the standard value YMAX side (side SR in FIG. 5) regarding the Y axis is performed. Since the contents of the processing are the same as those in ST1 to ST4, description thereof will be omitted.

Standard value YMIN and standard value Y regarding the Y-axis
After the determination of MAX is completed, next, ST9 to S
At T16, margin determination is performed on the standard value XMIN (side PS in FIG. 5) and standard value XMAX (side QR in FIG. 5) regarding the X axis. The specific procedure is the same as in ST1 to ST8, and therefore the description thereof is omitted.

ST17 (Display of Margin Judgment Result) As described above, the margin judgment can be performed for the characteristic items X and Y, and the result is displayed on the CRT or the printer 23 and the process is ended. At this time, if it is displayed near the display of the shmoo plot, the determination result is easy to see, which is convenient.

In the above determination, the standard value XMIN and the standard value XM are related to the step values ΔX and ΔY on the X and Y axes.
If AX, the standard value YMIN, and the standard value YMAX do not match the measurement points on the X and Y axes, the value of the measurement point closest to the standard value is used. Further, the standard value area P shown in FIG.
QRS was a rectangle with sides parallel to the X and Y axes,
The shape is not limited to this, and it may not be parallel like a diamond. Also,
The shape is not limited to a quadrangle, and may be a polygon such as a triangle, a pentagon, and a hexagon.

As described above, it is possible to automatically and accurately judge the margin by a mechanical process in a short time, and easily judge the quality of the IC. This is particularly effective when the number of shmoo plots to be measured is very large.

Example 2. Although the above-described first embodiment relates to the case of automatically determining the margin, the mechanical processing is performed based on the shmoo plot to automatically determine the presence or absence of the shape abnormality of the shmoo plot, and the IC It is also possible to easily know an abnormality in the characteristics of.

FIG. 6 is a flow chart showing the flow of the process of determining the shape abnormality of the shmoo plot of the automatic determination apparatus 1 according to the second embodiment.

FIG. 7 is a block diagram showing a concrete structure of the means for making the discontinuity judgment in the flowchart of FIG. In FIG. 6, reference numeral 12 receives Y-axis data for a predetermined X-axis coordinate in the Shmoo plot from the storage unit 3 and stores the data, and reads the stored data one by one based on a shift clock (not shown) for parallel-serial conversion. Shift register to perform, 13 is shift register 1
The counter is counted by the output of 2 and reset by a reset signal from a reset circuit (not shown). The counter 13 has its 2 bits (2 digits)
Output the eye data. For convenience of explanation, the storage means 3 is divided into cells by addresses so that a part of the stored content is shown. In the figure, Pass is 1, Fa
il is represented as 0. In addition, the shift register 12
It is assumed that 7-bit data is stored in.

FIG. 8 is a timing chart for explaining the operation of the means for making the discontinuity judgment shown in FIG. FIG. 9 is an example of a shmoo plot when the shape is abnormal.

Next, the operation of the determining apparatus of the second embodiment will be described with reference to FIGS. In the case of the shmoo plot having no characteristic abnormality, the boundary line C between the symbols F and P shows a smooth shape, but in the case of the shmoo plot having the characteristic abnormality, for example, as shown by a dotted line in FIG. A recess E is formed. Especially where Fa should be in the Pass area
When the il portion occurs, it is necessary to investigate the cause of the Fail and improve the IC so that it becomes Pass. Therefore, by determining the presence or absence of the recess E, I
It can be determined whether C is abnormal.

Specifically, based on the flowchart of FIG. 6, it is determined whether or not there is a discontinuity at the Pass point in the shmoo plot for any one column of the characteristic items X and Y. Here, the discontinuity means that there is at least one Fail point between the Pass points.

First, it is determined in ST1 to ST3 whether or not there is an abnormality in the data parallel to the Y axis. ST1 (X = XMIN) XMIN is set as the initial value of the X coordinate. XM here
IN is a standard value XMI that means a margin in FIG.
It is different from N and is the minimum measurement point on the X axis of the Shmoo plot. The same applies to XMAX, YMIN, and YMAX.

ST2 (Y = YMIN → YMAX, discontinuity determination) P between YMIN and YMAX for a predetermined X coordinate
It is determined whether there is a discontinuity in the ass point. Specific means for detecting the presence or absence of discontinuity will be described later.
If there is a discontinuity, the shape abnormality is recorded (ST21), the process for the X axis is terminated, and the process proceeds to ST4. If there is no discontinuity, proceed to ST3.

ST3 (X = MAX?) It is checked whether or not the X coordinate is XMAX. If it does not reach XMAX, the process proceeds to ST31, where X = X + ΔX, and S
Repeat T2 and ST3. If X = XMAX is reached, the process on the X axis is terminated and the process proceeds to ST4.

By the above ST1 to ST3, the abnormality in the Y-axis direction in the range of XMIN to XMAX and YMIN to YMAX of the shmoo plot can be determined.

Next, in ST4 to ST6, the same processing as that in the case of the Y-axis direction is performed in order to determine the abnormality in the X-axis direction. Since the specific operation is the same as in ST1 to ST3, its description is omitted.

ST7 (Display of Shape Abnormality Determination Result) Finally, the result of the shape abnormality determination is displayed near the shmoo plot, and the process ends.

Next, the operation of the means for determining discontinuity will be described. Although the shift register 12 is provided only in the Y-axis direction in FIG. 7, a similar shift register can be provided in the X-axis direction.

It is assumed that the shmoo plot data created by the tester 22 after the test is stored in the storage means 3 in advance. When determining a shape abnormality in the Y-axis direction, the Y-axis data is read from the storage means 3 and input to the shift register 12 in accordance with the X coordinate value set in ST1 or ST31 of FIG.

In the shift register 12, the Y-axis data is transferred bit by bit and input to the counter 13. The counter 13 performs a counting operation based on the output of the shift register 12. Here, when there is a shape abnormality, the output of the counter 13 becomes 1, and when there is no shape abnormality, the output of the counter 13 remains 0. This will be described in detail with reference to the timing chart of FIG.

FIG. 8A shows a timing chart when there is a shape abnormality. The abnormal shape means that P is not continuous and F is partially present as described above, and 1 is not continuous in the data input to the shift register 12. For example, assume that it is "0100100" as shown in FIG. Then, a plurality of pulses are input to the counter 13 as shown in FIG. 8A, so that the content of the counter 13 becomes 2 and its output (the output of the second digit of the binary counter) becomes 1. When the shape is abnormal as described above, the output of the counter 13 becomes 1. When there are a plurality of abnormal shapes, for example, “0101010”, the content of the counter 13 is 3
However, at that time, the abnormal shape can be determined by checking the other output of the counter 13. Specifically, it is sufficient to check whether the output of the counter 13 is larger than 1 by the comparator.

Next, the operation when there is no abnormal shape will be described. FIG. 8B shows a timing chart at this time. When there is no abnormal shape, the shift register 12
1 is continuous in the data input to. For example, assume that it is "0111100". Therefore, the content of the counter 13 is 1 because only one pulse is input to the counter 13. Therefore, the output of the counter 13 remains 0.

The reset signal in FIG. 8 is a signal for resetting the counter 13 when one row of data corresponding to a predetermined X coordinate is input to the shift register 12.

7 and 8 show the construction and operation of the means for determining the discontinuity in the Y-axis direction, the means for determining the discontinuity in the X-axis direction has the same construction and operation.

As described above, since the characteristic abnormality can be automatically determined, even if the number of shmoo plots to be determined is very large, the determination can be performed easily, quickly, and accurately. It is possible to reduce the burden on the measurer.

By combining the first embodiment and the second embodiment, it is possible to perform the margin determination and the shape abnormality determination at the same time, and the pass / fail determination is performed not only on the four sides of the margin region but also inside the region. It is possible to make a more accurate determination.

Also, the margin determination of the shmoo plot,
The shape abnormality determination is performed for each one shmoo plot, and the result is displayed near the shmoo plot. However, in some cases, the number of these shmoo plots is very large (for example, for 10 to 20 ICs, respectively). Dozens to hundreds are required). In such cases,
Since it takes a considerable amount of time to see only the determination results of each shmoo plot, only the results of the problematic shmoo plot may be displayed separately from the shmoo plot.

Example 3. Example 1 and Example 2 above are
Margin judgment and shape abnormality judgment were performed for one shmoo plot, but comparison was made between multiple shmoo plots so that when the product characteristics were improved, it was possible to easily judge whether or not the characteristics were improved. However, the result may be displayed.

FIG. 10 is a block diagram of the judging device according to the third embodiment. In the figure, 15 is storage means 16a-1.
Address selection means 16a to 16 for designating the same XY coordinates on the Shmoo plot for 6c and selecting the data recorded therein or writing the data.
c is a storage means for storing different data of the shmoo plot, the storage means 16a records the reference data, the storage means 16b records the comparison data, and the storage means 1
6c records the determination result. Reference numeral 17 is a judgment means for comparing the reference data stored in the storage means 16a with the comparison data stored in the storage means 16b and outputting a predetermined symbol to the storage means 16c in accordance with the relationship shown in FIG.
Is a means for displaying the determination result recorded in the storage means 16c.

FIG. 11 is a diagram showing the internal structure of the determination means 17 of FIG. In the figure, 171a to 171d
Is a logical product means (AND), and 172a to 172d are logical negation means (NOT).

Next, the operation will be described. The address selecting means 15 designates predetermined coordinates of the shmoo plot as described later, and outputs corresponding data from the storage means 16a and 16b as reference data and comparison data, respectively. The determination means 17 performs a predetermined process by the circuit of FIG. 11 and outputs the determination result to the storage means 16c.

As shown in FIG. 11, the judging means 17 performs processing based on the basic data and the comparison data. That is, when all data are P (= 1), AND171a
Operates, and the P display output means 173 outputs "P" based on this.
Is output. Further, when all the data are F (= 0), the AND 17 is performed via the NOTs 172a and 172b.
1b operates, and based on this, the F display output means 174 outputs "F". When one is P and the other is F, the AND 171c operates via the NOT 172c, and the + display output means 175 outputs "+".
AND171d operates via NOT172d,-
The display output means 176 outputs "-" or performs either operation.

Next, the details of the above determination operation will be described with reference to FIG.
This will be described using the flowchart of FIG. 2 and the shmoo plot of FIG. Here, FIG. 14 (a) is a shmoo plot before improving the characteristics of the product, FIG. 14 (b) is a shmoo plot after improving the characteristics of the product, and FIG. 14 (c) is a shmoo plot subjected to the determination processing. It shows a Moo plot.

First, in FIG. 12, ST1 (X = XMIN): The processing start position on the X axis is set in the area of the shmoo plot which is the target of the determination as to whether or not the characteristic has been improved. For example, the minimum value XM on the X axis of the Shmoo plot
Set IN.

ST2 (Y = YMIN) Similarly, the processing start position on the Y axis is set. For example,
Set the Y axis minimum value YMIN of the shmoo plot.
The determination process is performed over the entire region from the processing start position set in this way to the processing end position (XMAX, YMAX). Further, the processing of the coordinates in such an area is performed by the address selecting means 15 in FIG.

ST3 (Match?) Based on the output of the address selection means 15, storage means 16a, 16
For example, the data of the corresponding coordinates of the Shmoo plots of FIGS. 14A and 14B are read from b, and are output to the determination means 17. The determination means 17 compares the reference data with the comparison data and determines whether they match. If they match, the process proceeds to ST41, and if they do not match, the process proceeds to ST42.

ST41 (reference P?) When the reference data is P, in ST51 (recording of P), P is recorded at the coordinate as a determination result, and the storage means 1 is stored.
Output to 6c. This means that both the IC data before improvement (reference data) and the IC data after improvement (comparison data) are Pass, and both characteristics are good. On the other hand, when the reference data is F, in ST52 (recording of F), F is recorded at the coordinate as a determination result and output to the storage means 16c. This means that the characteristics of both the reference data and the comparison data are defective.

ST42 (reference F?) When the reference data is F, in ST53 (recording +), + is recorded in the coordinate concerned as a determination result, and the storage means 1 is recorded.
Output to 6c. This means that what was F in the reference data became P in the comparison data, which means that the characteristics of this IC were improved by the improvement. Therefore, I will use the + symbol. On the other hand, when the reference data is P, in ST54 (recording −), − is recorded at the coordinate as a determination result and output to the storage unit 16c. This means that what was P in the reference data was changed to F in the comparison data, which means that the characteristics of this IC were rather deteriorated by the improvement. Therefore, it will be represented by the-symbol. In addition, from ST3 to ST51
FIG. 13 shows a truth table obtained by the processing of ST54.

ST6 (Y = YMAX?) It is checked whether or not the upper limit of the Y-axis coordinate of the area of the shmoo plot to be processed has been reached. ST7 if the upper limit is reached
Proceed to (X = XMAX?). If the upper limit is not reached, S
The process proceeds to T61 (Y = Y + ΔY) to move to the next Y coordinate. In this way, the processes from ST3 to ST51 to 54 are repeated at intervals of ΔY from Y = YMIN to Y = YMAX.

ST7 (X = XMAX?) Similarly, it is checked whether or not the upper limit of the X-axis coordinate of the region of the shmoo plot to be processed has been reached. If the upper limit is reached, the process is terminated and ST8 (display) is displayed. move on. If the upper limit has not been reached, the process proceeds to ST71 (X = X + ΔX) and moves to the next X coordinate. Thus, from X = XMIN to X = XMA
The processes from ST3 to ST51 to 54 are repeated at intervals of ΔX until X.

ST8 (Display) Finally, the shmoo plot of the determination result stored in the storage means 16c is displayed for each point, and the process ends.

A shmoo plot processed based on the flowchart of FIG. 12 is shown in FIG. 14 (c). In FIG. 14 (c), the common part between the area A in which the P symbol of FIG. 14 (a) of the reference data is displayed and the area B of the comparative data in which the P symbol of FIG. 14 (b) is displayed. A P symbol is displayed in area C of. In addition, a symbol-in a region D that is a common portion (a portion of the reference data that is P and a portion of the comparison data that is F) between the area A of the reference data and the portion other than the area B of the comparison data.
Is displayed. Further, a symbol + is displayed in a region E which is a common portion (a portion where the reference data is F and the comparison data is P) between the portion other than the reference data area A and the comparison data area B. As can be seen from FIG. 14C, the characteristic is improved by the improvement in the area E on the upper right of the shmoo plot, and conversely, the characteristic is deteriorated by the improvement in the area D on the left side.

As described above, according to the third embodiment, since the comparison result is displayed on the shmoo plot by the easily identifiable symbol, it is possible to easily recognize how much the characteristics are improved before and after the improvement of the product characteristics. can do.

In the above description, P, F, +,
Although the Shmoo plot determination result is displayed by the four symbols −, it is not limited to this, and another symbol may be used as long as the four types of comparison results can be identified.

[0073]

[0074]

[0075]

As is evident from the foregoing description, according to the present invention, test results der of the electrical characteristics of the storage means test object
Storing a shmoo plot, the address generating means generates the address of the storage means, and the shmoo plot is generated from the storage means.
Read out multiple data of
Shmu based on discontinuities in multiple data in a set
-By determining the shape abnormality of the plot,
-Since the quality of the plot is judged, it is easy to judge the presence or absence of characteristic abnormality based on the shmoo plot which is the test result.
And it can be performed in a short time.

[0076]

[Brief description of drawings]

FIG. 1 is a block diagram of an automatic test result determining apparatus according to a first embodiment of the present invention.

FIG. 2 is a block diagram of a test system according to the first embodiment of the present invention.

FIG. 3 is a flowchart for explaining the operation of the automatic test result judging apparatus according to the first embodiment of the present invention.

FIG. 4 is a flow chart for explaining the operation of the automatic test result judging apparatus according to the first embodiment of the present invention.

FIG. 5 is a diagram for explaining the operation of the automatic test result determining apparatus according to the first embodiment of the present invention.

FIG. 6 is a flowchart for explaining the operation of the test result automatic judging apparatus according to the second embodiment of the present invention.

FIG. 7 is a block diagram of a shape abnormality determining unit according to a second embodiment of the present invention.

FIG. 8 is a timing chart for explaining the operation of the shape abnormality determining unit according to the second embodiment of the present invention.

FIG. 9 is a shmoo plot for explaining the operation of the test result automatic determination apparatus according to the second embodiment of the present invention.

FIG. 10 is a block diagram of an automatic test result determining apparatus according to a third embodiment of the present invention.

FIG. 11 is a block diagram of a judging means according to the third embodiment of the present invention.

FIG. 12 is a flowchart for explaining the operation of the automatic test result judging apparatus according to the third embodiment of the present invention.

FIG. 13 is a diagram for explaining the operation of the determination means according to the third embodiment of the present invention.

FIG. 14 is a diagram for explaining the operation of the test result automatic determination apparatus according to the third embodiment of the present invention.

FIG. 15 is a block diagram of a conventional test system.

FIG. 16 is an example of a shmoo plot.

[Explanation of symbols]

1 Automatic judgment device 2 address selection means 3 storage means 4 Judgment means 12 shift registers 13 counter 15 Address selection means 16 storage means 17 Judgment means

─────────────────────────────────────────────────── ─── Continuation of the front page (56) Reference JP-A-4-104073 (JP, A) JP-A-4-130240 (JP, A) JP-A-4-186600 (JP, A) JP-A-4- 278556 (JP, A) JP 5-28800 (JP, A) JP 5-325594 (JP, A) JP 57-15296 (JP, A) JP 58-207647 (JP, A) JP-A-59-228726 (JP, A) JP-A-63-185000 (JP, A) JP-A-64-41878 (JP, A) JP-B 5-30224 (JP, B2) JP-B 46-31373 (JP, B1) (58) Fields surveyed (Int.Cl. ⁷ , DB name) G01D 21/00 G01R 31/28

Claims (2)

(57) [Claims] 1. A storage means for storing a shmoo plot which is a test result of the electrical characteristics of a test object, an address generation means for generating an address of the storage means, and the above based on the output of the address generation means. From memory means Shmoopro
Reads a plurality of data of Tsu door, read Shumupu
Shoe based on non continuity in a plurality of data in the lot
The shoe by determining the shape abnormality mu plot
Automatic determination apparatus test results and a determination means for determining acceptability of Mu plot. 2. A test for electrical characteristics of a test object.
The resulting Shmoo plot is stored in the storage means, and
Based on the output of the address generation means that generates the address of the storage means
Read multiple data of Shmoo plot from the above storage means
Multiple data in the shmoo plot that is read and read
Anomaly of shmoo plot based on discontinuity in
The quality of the shmoo plot is judged by judging
Automatic determination method of test results to be set.