JPH11190765A - Semiconductor test apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve a throughput related to a calibration execution time by carrying out calibration when a calibration data preservation file is absent although a temperature changes by not smaller than a predetermined temperature, registering in a management book, and reusing the preservation file if the file is present. SOLUTION: It is checked whether or not a temperature in a semiconductor test apparatus changes by not smaller than a predetermined temperature (e.g. 2 deg.C). When the temperature changes by not smaller than 2 deg.C, a calibration file is read out from a file management book. If a calibration data file of the same temperature is not present in the management book, a calibration is carried out and registered in the file management book. When the temperature changes by not smaller than a set temperature after a predetermined time, a data file containing the calibration data of the same temperature is reused if the file is present, and the data is set to a correction circuit, thereby eliminating an execution time for the calibration.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a semiconductor test apparatus having a timing for maintaining the accuracy of a measurement system due to a temperature change and other calibration functions.

[0002]

2. Description of the Related Art An example of the prior art will be described with reference to FIGS. First, the hardware of a general semiconductor test apparatus will be described. As shown in FIG. 3, the calibration part of the semiconductor test apparatus includes a tester processor (TP) 70 for controlling each unit via a bus,
A workstation (WS) 80 serving as an interface with the operator, a memory 90 serving as storage means such as a storage medium, and a timing generator 10 (TG; Timing G).
enerator) and waveform shaper 20 (FC: Format Cotrol)
And the pattern generator 50 (PG: Pattern Genera)
tor), variable delay units 31 to 3n, and drivers 41 to 4n
And a multiplexer 60.

Hereinafter, an operation of each unit and an operation example of calibrating timing at an output pin of a driver will be described.

The timing generator 10 generates a test cycle and a reference timing signal of a test signal from a basic clock.

[0005] The pattern generator 50 generates pre-programmed logic data in synchronization with the basic clock.

[0006] The waveform shaper 20 receives the logic data from the pattern generator 50 and shapes it into a desired test pattern waveform using the reference timing signal generated by the timing generator 10.

The variable delay units 31 to 3n are connected to drivers 41 to
4n is a fine adjustment delay element for adjusting the difference in propagation delay of the test signal at the 4n output terminal. And, as shown in FIG.
When the same timing is set, each of the drivers 41 to 4
The skew between the pins at the output terminal of n is adjusted by the variable delay units 31 to 3n so that the skew is substantially zero.

Furthermore, it is necessary to prevent skew between the pins at the output terminals of the drivers 41 to 4n even if the ambient temperature changes. For this reason, the temperature inside the semiconductor test apparatus is measured, and the calibration is automatically performed when the temperature changes more than a specified value every predetermined time or at an arbitrary set time.

The temperature measurement inside the semiconductor test apparatus is
For example, a change in the propagation delay of the gate 12 in the timing generator 10 shown in FIG. 3 is used as a temperature sensor. That is, the switch SW1 in the timing generator 10 is switched to the S side to form a system loop, and the loop frequency Fs
Is counted by a counter 13, and a change from the value measured last time is calculated by a calculation circuit 14 to obtain a temperature change.

The skew between the pins is determined by switching the switch SW1 in the timing generator 10 to the T side.
The output signal of each pin is sequentially selected by the multiplexer 60,
An oscillation loop is formed, the loop frequency Ft is counted by a counter 13, and a difference from a reference pin is calculated by a calculation circuit 14 to obtain delay time error data. And
As an example of the inter-pin skew correction circuit, the number of D / A converters 15 corresponding to the number of pins n and the number of variable delay devices 31
To 3n, the delay time error data of each driver is set in the corresponding D / A converter 15 to be converted into an analog voltage, and is supplied to the corresponding variable delay units 31 to 3n. Skew is almost zero. When the variable delay units 31 to 3n are not analog control type variable delay units but digital control type variable delay units, there is no D / A converter 15 and the variable delay units 31 to 3n are directly set. Is done.

Generally, the number of pins of a semiconductor test apparatus is several hundreds to
Since the number of pins is as large as several thousand, the time required for calibration also takes several tens of seconds to several minutes. The timing calibration items include, in addition to the driver-pin skew described above, for example, a comparator-pin skew,
There are skew between strobes, driver I / O switching timing, skew between driver and comparator, and the like, and a predetermined accuracy is maintained by performing calibration.

Next, an example of a conventional timing calibration execution method will be described below by referring to a flowchart of FIG.

1. The calibration is called and executed by a CALL statement in the test program (CALL
CALB).

2. Calibration file (CAL
FILE) is checked (Step 1)
00). If there is a calibration file, the process proceeds to step 200. If there is no calibration file, the process proceeds to step 110.

3. The temperature inside the semiconductor test device is measured (step 200).

4. It is checked whether a predetermined time, for example, 10 minutes, has elapsed since the previous calibration was executed (step 300). If 10 minutes have elapsed, the process proceeds to step 310. If 10 minutes have not elapsed, the process proceeds to step 400.

5. The time data of the calibration file is rewritten (step 400).

6. The data of the calibration file is set in the delay time correction circuit (step 60).
0). Then, the calibration program is ended, and the program returns to the calling program (RETUR).
N).

[7] It is checked whether the temperature inside the semiconductor test apparatus has changed by a predetermined temperature, for example, 2 ° C. or more (step 310). If it has changed by 2 ° C. or more, the process proceeds to step 120. If the temperature has not changed by 2 ° C. or more, the process proceeds to step 400.

8. If there is no calibration file, the system temperature is measured (step 110).

9. A new calibration is executed (step 120).

10. A new calibration file is created (step 130).

11. Terminates the calibration program and returns to the calling test program (R
ETURN).

As can be seen from the above description of the steps, the calibration is executed each time a predetermined time has elapsed and there has been a change above the set temperature. Therefore, each calibration requires several tens of seconds to several minutes, and during that time semiconductor testing cannot be performed.
There is a disadvantage that the throughput of the semiconductor test apparatus is reduced.

As an example of the above-described timing calibration, the case of performing the skew between the pins of the driver has been described. However, the skew between the pins of the comparator and the driver I / O timing error are similarly executed.

Next, online initialization will be described with reference to FIG. The online initialization is for calibrating the reference voltage, current and offset level of the system. The initialization is performed at power-on and before the start of the device test when the temperature reaches a specified temperature, for example, ± 5 ° C. or more. The execution time of this online initialization also takes tens of minutes. The initialization items include, for example, driver output level offset, comparator offset, calibration of internal voltage reference and resistance reference, device power supply voltage, current offset and gain, and the like. Try to maintain accuracy.

FIG. 6 shows a flowchart of the conventional online initialization, and the execution procedure will be described in a bulleted manner.

1. It checks whether the device test program has been started and waits for a loop until the start is detected. If it is started, the subsequent processing steps are performed prior to the execution of the device test program (step 710). 2. It is checked whether a specified time, for example, one hour, has elapsed since the previous initialization. If the specified time has not yet elapsed, the process proceeds to step 750. If the specified time has elapsed, the process proceeds to step 200 (step 720). 3. Measure the temperature inside the semiconductor test equipment (Step 2
00). 4. If the current measured temperature has not changed by more than a specified temperature, for example, ± 5 ° C. from the measured temperature at the time of the previous initialization, the process proceeds to step 750, and if it has changed by more than the specified temperature, the process proceeds to step 740 (step 7).
30). 5. By executing the new online initialization and calibrating the voltage, current, offset level, etc. at the current temperature, the initialization data is updated and set in the tester hardware resources (setting register, memory, etc.).
Predetermined measurement accuracy at the current temperature is maintained. The temperature value Tx and time information at this time are stored in the next steps 720 and 73.
0 is stored for comparison check (step 74)
0). 6. With the predetermined measurement accuracy maintained, the device test program starts executing (step 750).

As can be seen from the above description of the steps, several ten minutes are consumed each time the online initialization is executed. Therefore, the device test cannot be performed during the execution time. As a result, the throughput of the semiconductor test apparatus is reduced.

[0030]

As described above, the semiconductor test apparatus requires several tens of seconds to several minutes to execute calibration, and takes several tens of minutes to execute online initialization. In the meantime, since the semiconductor test cannot be performed, there is a practical difficulty that the throughput of the semiconductor test apparatus is reduced. Therefore, the problem to be solved by the present invention is to provide a semiconductor test apparatus which improves the throughput related to the calibration execution time or the online initialization execution time by reusing the saved data of the calibration data or the initialization data. The purpose is to provide.

[0031]

FIGS. 1 and 2 show a solution according to the present invention. First, in order to solve the above-described problem, in the configuration of the present invention, the temperature in the apparatus is measured every set time or every predetermined time, and is compared with the temperature at the time of the previous calibration update. In a semiconductor test apparatus that performs timing calibration when there is a change above a temperature, when the temperature changes above a predetermined temperature, a file for storing calibration data at that temperature is not registered in the file management ledger. In the case where the calibration is actually performed and the file management ledger is provided and registered, if the file of the previously acquired calibration data at the temperature is in the file management ledger, the calibration data is stored in the file according to the temperature. Semiconductor that features reuse of files and no actual calibration It is a test apparatus.

According to the present invention, by reusing stored data of the stored calibration data, it is possible to realize a semiconductor test apparatus capable of reducing the calibration execution time at the same temperature as the measured temperature. .

FIG. 7 shows a solution according to the present invention. Second, in order to solve the above-mentioned problem, in the configuration of the present invention, the temperature in the apparatus is measured before the device test,
In a semiconductor test apparatus that executes online initialization when there is a change of a predetermined temperature or more compared to the temperature at the time of the previous online initialization update,
Upon detection of a temperature change equal to or greater than a predetermined value, it is checked whether or not the measured temperature value Tx is a registered temperature value by using a file management ledger (for example, a reference table 250). If you have not registered,
The measurement of the initialization is performed, the obtained initialization data is updated and set in a tester hardware resource (setting register, memory, or the like), and the obtained initialization data is stored together with the temperature value Tx in the storage medium 280 so that it can be reused thereafter. Second, when the temperature value Tx has already been registered, the initialization storage data S290 corresponding to the temperature value Tx is read from the storage medium 280 and updated and transferred to the tester hardware resource. Semiconductor testing equipment.

According to the present invention, by reusing the stored data of the stored initialization data,
At the same temperature as the measured temperature, it is possible to realize a semiconductor test apparatus capable of reducing the online initialization execution time.

Further, the registration information for each temperature value registered in the file management ledger may be erased by turning off the power, by holding the registration information even when the power is turned off, or by an operator or automatically. The above-described semiconductor test apparatus is characterized in that it has an erasing mode for erasing specific registration information (for example, registration information having passed a desired time or more).

[0036]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the present invention will be described in the following examples.

[0037]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Timing calibration according to the present invention will be described with reference to FIGS. The hardware configuration of the semiconductor test apparatus is the same as the conventional one shown in FIG. Next, an example of the calibration execution method according to the present invention will be described below in a bulleted manner with reference to the flowcharts of FIGS.

1. The calibration is called and executed by a CALL statement in the test program (CALL
CALB).

2. Calibration file (CAL
FILE) is checked (Step 1)
00). If there is a calibration file, the process proceeds to step 200. If there is no calibration file, the process proceeds to step 110.

3. The temperature inside the semiconductor test device is measured (step 200).

4. It is checked whether a predetermined time, for example, 10 minutes, has elapsed since the previous calibration was executed (step 300). If 10 minutes have elapsed, the process proceeds to step 310. If 10 minutes have not elapsed, the process proceeds to step 400.

5. The time data of the calibration file is rewritten (step 400).

6. The file in the file management ledger is changed to the rewritten time data (step 500).

7. The data of the calibration file is set in the delay time correction circuit (step 60).
0). Then, the calibration program is ended, and the program returns to the calling program (RETUR).
N).

8. It is checked whether the temperature inside the semiconductor test apparatus has changed by a predetermined temperature, for example, 2 ° C. or more (step 310). If it has changed by 2 ° C. or more, the process proceeds to step 320. If the temperature has not changed by 2 ° C. or more, the process proceeds to step 400.

9. If there is no calibration file, the system temperature is measured (step 110).

10. A new calibration is executed (step 120).

11. A new calibration file is created (step 130).

12. A new calibration file is registered in the file management ledger (step 140). Then, the calibration program ends, and the program returns to the calling program (RETURN).

13. The calibration file is read out from the file management ledger (step 320).

14. It is checked whether a file of the calibration data of the same temperature is registered in the file management ledger (step 330). If there is no calibration data file of the same temperature, the process proceeds to step 331. If there is a calibration data file of the same temperature, the process proceeds to step 340.

15. The same calibration data at that temperature is set in the delay time correction circuit (step 3).
40). Then, the calibration program ends, and the program returns to the calling program (RETU).
RN).

The calibration at the temperature when the temperature changes by 16.2 ° C. or more is executed (step 33).
1).

A calibration file at the temperature when the temperature changes by 17.2 ° C. or more is created (step 332).

The calibration file at the temperature when the temperature changes by 18.2 ° C. or more is registered in the file management ledger (step 333).

19. Terminates the calibration program and returns to the calling program (RET
URN).

As can be understood from the above description of the steps, when a predetermined time has elapsed and there is a change over the set temperature, if there is a calibration data file of the same temperature, the data file is reused. By setting the data in the correction circuit, the calibration execution time is not required. Therefore, in this case, the calibration execution time is not required for several tens of seconds to several minutes, and the semiconductor test can be executed immediately, so that the throughput of the semiconductor test apparatus can be improved.

Next, the online initialization of the present invention will be described. An example of a method of executing the online initialization will be described below in a bulleted manner with reference to the flowchart of FIG. Steps 710, 720, 2
Since 00, 730, and 750 are the same as those in the related art, the description is omitted.

1. This is a step of checking whether stored data at the same temperature is registered (step 81).
0). That is, upon receiving the temperature value Tx measured in step 200, it is compared with the past temperature values T1, T2 to Tn in the reference table 250 shown in FIG. 8 to check whether the same temperature value is registered. If not, the process proceeds to step 820. If registered, go to step 830.

2. This is the step of executing online initialization and saving and registering (step 820). That is,
In the same manner as described above, a new online initialization is performed to obtain calibration initialization data such as voltage, current, and offset level, and the obtained initialization data is updated and set in the tester hardware resources. Furthermore, it registers so that it can be reused thereafter. In this registration, the temperature value Tx is stored in the additional position 255 at the end of the reference table 250, and the acquired initialization data is stored and stored in a new area 295 of the initialization storage data S290 of the storage medium 280 in correspondence with the temperature value Tx. In addition, as before,
At this time, the temperature value Tx and the time information are also stored in steps 720 and 7.
Needless to say, it is stored at 30 for comparison check.

3. Existing initialization save data S2
This is the step of reusing 90 (step 830).
That is, the initialization storage data corresponding to the temperature value Tx is read from the corresponding storage area of the storage medium 280, and the read initialization storage data is updated and transferred to the tester hardware resources. As a result, there is obtained a great advantage that, as in the conventional case, the time of several tens of minutes of initializing each time is eliminated despite the same temperature value. In a continuous operation day and night on a mass production line, usually, the environmental temperature is periodically changed, and thus the effect is obtained with the passage of days.

The present invention is not limited to the above embodiment. For example, as the above-described registration and holding form of the calibration data and the registration and holding form of the initialization data, firstly, all registration information is reset (erased) by turning off the power, and secondly, an operator or automatically Are manually reset, for example, manually resetting registration information after a desired time or more, or individually resetting arbitrary registration information, and thirdly, holding even when the power is turned off. Normally, all registration information is automatically reset when the power is turned off. However, if desired, the stored data may be held until the operator manually resets the data or before the power is turned off.

[0063]

According to the present invention, the following effects can be obtained from the above description. That is, if a predetermined time has elapsed and there has been a change above the set temperature, if a file of calibration data or online initialize data at the same temperature has already been registered, the data file is reused. This has the effect of reducing the number of times of performing timing calibration and online initialization. Therefore, in this case, the calibration execution time is several tens seconds to several minutes,
Since tens of minutes of online initialization are not required, and the semiconductor test can be executed immediately, the effect of improving the throughput of the semiconductor test apparatus is great.

[Brief description of the drawings]

FIG. 1 is a first flowchart of timing calibration according to the present invention.

FIG. 2 is a second flowchart of timing calibration according to the present invention.

FIG. 3 is a block diagram for calibrating the timing of the semiconductor test apparatus.

FIG. 4 is a diagram showing a skew between pins of a driver output of the semiconductor test apparatus.

FIG. 5 is a flowchart of a conventional timing calibration.

FIG. 6 is a flowchart of a conventional online initialization.

FIG. 7 is a flowchart of online initialization according to the present invention.

FIG. 8 is a diagram illustrating a reference table and a storage medium according to the present invention.

[Explanation of symbols]

SW1 switch 10 Timing generator (TG; Timing Gen)
12) Gate 13 Counter 14 Arithmetic circuit 15 D / A converter 20 Waveform shaper (FC: Format Controller) 31-3n Variable delay unit 41-4n Driver 50 Pattern generator (PG: Pattern Gene)
60) Multiplexer 70 Tester processor (TP) 80 Workstation (WS) 90 Memory 250 Lookup table 280 Storage medium S290 Initialization storage data

Claims (3)

[Claims] 1. A semiconductor test apparatus for measuring a temperature at a set time or at a predetermined time and performing a timing calibration when a change over a predetermined temperature occurs. If there is no calibration data storage file at that temperature, perform calibration and register with the file management ledger.If there is a previously acquired calibration data file at that temperature, A semiconductor test apparatus characterized by reusing the saved file of calibration data based on temperature. 2. A semiconductor test apparatus for measuring the temperature inside the apparatus prior to a device test and performing an online initialization when a change in the temperature is higher than a predetermined temperature. A file management ledger is used to check whether the measured temperature value is a registered temperature value. First, if the temperature value is unregistered, the actual online initialization measurement is performed. The initialization data is updated and set in the tester hardware resources, and the obtained initialization data is registered and stored in a storage medium. Secondly, when the temperature value is already registered, the initialization storage data corresponding to the temperature value is stored. A semiconductor test apparatus characterized by reading from a storage medium and transferring the updated data to a tester / hardware resource. 3. An erasing mode of the registration information for each temperature value registered in the file management ledger is a mode in which the registration information is erased when the power is turned off, a mode in which the registration information is held even when the power is turned off, or an operator or automatically specifies 2. An erasing mode for erasing the registration information of the electronic device.
Or the semiconductor test apparatus according to 2.