JP2008164409A - Semiconductor test equipment - Google Patents

Abstract

A semiconductor test apparatus capable of accurately detecting and calibrating a temperature change in a transmission path through which a signal is transmitted is provided.
In a semiconductor test apparatus, a voltage value of a signal generated by a signal generation unit and transmitted through a transmission path is converted into a signal transmitted through the transmission path by first and second measurement circuits. The calibration value determination circuit 150 compares the voltage value data of each of these signals and determines whether or not the difference is not less than a predetermined threshold value. If it is determined that the difference is greater than or equal to a predetermined threshold value, an arithmetic process is performed to calculate an average value of the voltage values of each signal, and the voltage value of the signal is corrected to this average value, so Output to the DUT.
[Selection] Figure 1

Description

  The present invention relates to a semiconductor test apparatus for performing a test by outputting a signal to an object to be tested such as an IC device or a memory device, and more particularly to a circuit configuration for calibrating an error of a signal voltage generated inside the apparatus. .

  2. Description of the Related Art Conventionally, in a semiconductor test apparatus that performs a test such as function confirmation on a device under test (hereinafter referred to as a DUT) that is a semiconductor device such as an IC device or a memory device, a signal generator such as a pattern generator inside the apparatus When the generated test signal is transmitted through the transmission path, it performs an operation to calibrate and output the signal voltage error caused by impedance characteristics and temperature changes in each circuit such as a buffer circuit and amplifier. .

In the semiconductor test apparatus described in Patent Document 1 below, a multiplexer circuit in which each terminal of an IC to be inspected and a standard voltage generator are connected, and each signal output from the multiplexer circuit is passed through a scanner buffer circuit. A voltage measuring device that measures voltage values by switching sequentially is provided. Then, based on the measured value of the voltage value of the signal selected by the calibration voltage selection unit, the calibration voltage calculation unit calculates the calibration value of each transmission path in advance. Of the signals from the terminals of the IC under test input by the multiplexer circuit, correction is performed using the calibration value of the path calculated by the calibration voltage calculation means with respect to the measured voltage value of the signal selected by the DUT selection means. (For example, refer to Patent Document 1).
Japanese Patent Laid-Open No. 10-227837 (FIG. 1)

  Further, in a conventional semiconductor test apparatus, calibration is performed as follows for an error in signal voltage caused by a temperature change when a test signal generated inside the apparatus is transmitted through a transmission path. FIG. 4 is an explanatory diagram showing the configuration of a semiconductor test apparatus 200 in the prior art. In the semiconductor test apparatus 200, when the signal generator 210 realized by the pattern generator generates a test signal for testing the DUT, the generated signal is transmitted in various circuits such as an amplifier and a multiplexer. The voltage value of the signal is measured in the measurement circuit 230 that is transmitted through the path 220 and provided in the output portion to the DUT connected to the outside.

  Then, the temperature is regularly measured with a thermometer 240 provided in the apparatus, and when there is a certain degree of deviation (temperature change) compared to the temperature measured last time, it is set in advance for each temperature. The calibration value is calibrated by performing processing such as adding a calibration value corresponding to the temperature measured by the thermometer 240 to the voltage value of the signal with reference to the calibration value.

  However, in such a conventional semiconductor test apparatus 200, the thermometer 240 is provided inside the semiconductor test apparatus 200 itself. However, the thermometer 240 only measures the temperature around the provided position. Therefore, the temperature at the part of the transmission path 220 or the measurement circuit 230 where the error of the signal voltage actually occurs is not accurately measured. Therefore, conventionally, it cannot be said that the calibration is appropriately performed using the calibration value corresponding to the temperature at which the signal voltage error occurs.

  Accordingly, an object of the present invention is to provide a semiconductor test apparatus capable of accurately detecting and calibrating a temperature change in a transmission path through which a signal is transmitted.

  In order to achieve the above problems, a semiconductor test apparatus according to the present invention transmits a signal generating means for generating a signal to be output to an object to be tested and a signal generated by the signal generating means. Transmission path, a plurality of voltage measurement means for measuring the voltage value of the signal transmitted through the transmission path, and transmission through the transmission path signal based on the voltage value of the signal measured by the plurality of voltage measurement means Signal calibration means for calibrating the voltage value of the signal to be transmitted.

  With such a configuration, processing such as determination is performed based on the voltage values of the signals measured by the plurality of voltage measuring means, and each signal is determined based on the characteristics of the temperature change with individual differences for each of the plurality of voltage measuring means. If there is a divergence between the voltage values, it can be determined that the transmission path (or the voltage measuring means itself) is affected by a temperature change. In the present invention, by performing calibration in such a case, the signal is calibrated by accurately determining that the influence of the temperature change has occurred on the transmission path, etc. without relying only on the change in the ambient temperature inside the apparatus. It can be carried out.

  In addition, another semiconductor test apparatus according to the present invention includes a signal generation unit that generates a signal to be output to an object to be tested, a transmission path that transmits a signal generated by the signal generation unit, and the transmission A first voltage measuring means for measuring a voltage value of a signal transmitted through the path within a first range; and a second voltage measurement unit configured to measure a voltage value of the signal transmitted through the transmission path from a second range different from the first range. The voltage value of the signal transmitted through the transmission path signal is calibrated based on the voltage value of the signal measured by the second voltage measuring means measuring within the range and the first and second voltage measuring means, respectively. And a signal calibrating means for performing the above.

  In the above configuration, the first voltage measurement unit and the second voltage measurement unit have different measurement ranges, but here, it is assumed that measurement can be performed by either of the two voltage measurement units within a certain range. ing. That is, it is assumed that the first measurement range and the second measurement range partially overlap. In this case, since the first and second voltage measuring means have different fluctuation characteristics (temperature dependence) with respect to the change in unit temperature, even if the same signal is measured, these are actually measured voltages. There will be a discrepancy between the values. In this way, in the present invention, the signal is calibrated based on the divergence between the two measurement results, so that the temperature in the transmission path or the like does not depend on only the change in the measured value of the ambient temperature using the thermometer. Appropriate calibration can be performed against the effects of changes.

  In the above-described semiconductor test apparatus, the signal calibration means determines whether or not the voltage value of the signal measured by the first and second voltage measurement means is more than a preset threshold value. As a result of the determination by the determination means and the voltage determination means, the average of the voltage values of the signals measured by the first and second voltage measurement means when it is determined that the difference is greater than a preset threshold value Voltage calibration means for calibrating the voltage value of the signal based on the value may be included.

  According to such a configuration, the voltage value of the signal measured by the two voltage measuring means exceeds a certain threshold by utilizing the difference in characteristics with respect to the change in unit temperature for each of the first and second voltage measuring means. If there is a divergence, it can be determined that the transmission path or the like is affected by a temperature change. In this case, the signal can be calibrated based on the average value of the voltage values measured by the two voltage value measuring means, so that the calibration can be appropriately performed according to the temperature change.

  According to the semiconductor test apparatus according to the present invention, it is possible to calibrate the signal by accurately recognizing the influence of the temperature change generated on the transmission path, rather than relying solely on the change in the ambient temperature inside the apparatus. The effect that it becomes possible is acquired.

Hereinafter, an embodiment of the present invention will be described in detail with reference to the drawings.
FIG. 1 is an explanatory diagram showing the overall configuration of a semiconductor test apparatus 100 in the present embodiment. The semiconductor test apparatus 100 generates an analog signal such as a test signal for performing a function confirmation test on a DUT that is a semiconductor device such as an IC device or a memory device, and transmits the analog signal when transmitting the signal through the apparatus. This is a device that calibrates the error of the signal voltage caused by temperature change due to long-time operation etc. and outputs it to the object under test.

  The semiconductor test apparatus 100 includes a signal generator 110 that generates an analog signal such as a test signal for testing an object to be tested. The signal generator 110 is a pattern generator, for example, and is connected to the transmission path 120. During a test operation of the semiconductor test apparatus 100, an analog signal such as a test signal is generated and output to the transmission path 120.

  In addition, the semiconductor test apparatus 100 includes a transmission path 120 including various circuits and elements such as an amplifier and a buffer circuit that amplify the signal generated by the signal generation unit 110.

  The semiconductor test apparatus 100 includes first and second measurement circuits 130 and 140 that measure voltage values of signals transmitted through the transmission path 120. The first and second measurement circuits 130 and 140 are realized using, for example, an A / D converter or the like, and these are connected to the transmission path 120 and the calibration content determination circuit 150. The first and second measurement circuits 130 and 140 measure the voltage value of the signal transmitted through the transmission path 120 and output the measured voltage value data and signal of each signal to the calibration content determination circuit 150. Have.

  FIG. 2 is an explanatory diagram showing an example of characteristics of the first and second measurement circuits 130 and 140 with respect to a specific temperature change. Each of the first and second measurement circuits 130 and 140 has a characteristic with respect to a specific temperature change. As shown in FIG. 2, the voltage error per unit temperature of the first measurement circuit 130 is 0.1 V / The voltage error per unit temperature of the second measurement circuit 140 is 0.2 V / ° C. When the voltage value at the time of signal generation is 2 V and the temperature change is 3 ° C., the voltage error is 2.3 V. , 2.6V is measured.

  The semiconductor test apparatus 100 includes a calibration content determination circuit 150 that compares and determines the voltage value of each signal measured by the first and second measurement circuits 130 and 140. The calibration content determination circuit 150 is connected to the first and second measurement circuits 130 and 140 and the feedback calculation circuit 160, and the voltage value of each signal measured by the first and second measurement circuits 130 and 140 is measured. It has a function of comparing data and determining whether or not the voltage values of these signals are more than a predetermined threshold value. Here, the predetermined threshold is a preset numerical value stored in a memory included in the calibration content determination circuit 150. If there is a discrepancy greater than this value between the voltage values of the signals measured by the first and second measurement circuits 130 and 140, it is determined that a temperature change has occurred and calibration is required.

  The semiconductor test apparatus 100 includes a feedback arithmetic circuit 160 that performs calibration by correcting the voltage value of a signal based on the result determined by the calibration content determination circuit 150. The feedback arithmetic circuit 160 is connected to the transmission path 120 and the calibration content determination circuit 150. When the calibration content determination circuit 150 compares the voltage value data of each signal, the feedback arithmetic circuit 160 is more than a predetermined threshold value. It has a function of calibrating the voltage value of the signal when it is determined. The signal voltage value is calibrated by correcting the voltage value of each signal measured by the first and second measurement circuits 130 and 140 to an average value, and is output to the DUT via the transmission path 120.

  In addition, the semiconductor test apparatus 100 includes a thermometer 170 that measures the temperature inside the apparatus. The thermometer 170 outputs the measured ambient temperature to the calibration content determination circuit 150.

  Next, the calibration operation of the semiconductor test apparatus 100 in the present embodiment will be described using the flowchart shown in FIG.

  Step S201: When the DUT is connected and a test such as function confirmation is started, the semiconductor test apparatus 100 causes the signal generator 110 to generate an analog signal such as a test signal. When a signal is generated, various processes such as outputting to the transmission path 120 and amplifying the signal by an amplifier are executed and transmitted.

  Step S202: The semiconductor test apparatus 100 performs a process of measuring the voltage value of the signal transmitted through the transmission path 120 by the first and second measurement circuits 130 and 140. When the signal is transmitted through the transmission path 120, the semiconductor test apparatus 100 measures the voltage value of the signal by the first and second measurement circuits 130 and 140, and calibrates the data of the measured voltage value and the signal. Output to the determination circuit 150.

  Here, for example, when the voltage value of the signal when the signal generator 110 is generated is 2 V, and the temperature change caused by long-time operation or environmental change of the semiconductor test apparatus 100 is 3 ° C., the first The second measurement circuits 130 and 140 measure the voltage values of the signals as 2.3 V and 2.6 V, respectively, and output them together with the signals to the calibration content determination circuit 150.

  Step S203: The semiconductor test apparatus 100 compares the voltage value data of each signal output from the first and second measurement circuits 130 and 140 by the calibration content determination circuit 150, and whether or not the difference exceeds a predetermined threshold value. The process which determines is performed. Here, for example, when the threshold value stored in the internal memory of the calibration content determination circuit 150 is 0.2 V, the voltage value of the signal output from the first and second measurement circuits 130 and 140. It is determined that the difference between 3V and 2.6V is greater than the threshold.

  Step S204: As a result of the determination by the calibration content determination circuit 150, the semiconductor test apparatus 100 determines that the voltage value data of each signal has deviated beyond a predetermined threshold (YES in Step S203), and feedback. Processing for calibrating the voltage value of the signal is performed by the arithmetic circuit 160. The semiconductor test apparatus 100 performs arithmetic processing by the feedback arithmetic circuit 160 and calculates an average value of voltage values of the respective signals measured by the first and second measurement circuits 130 and 140. Then, the feedback arithmetic circuit 160 controls the transmission path 120 so as to correct the voltage value of the signal to the calculated average value. The transmission path 120 performs necessary correction processing on the signal input from the signal generation unit 110 based on the output signal of the feedback arithmetic circuit 160, and outputs the corrected signal to the DUT. Here, for example, if the measurement voltage value of the first measurement circuit 130 is 2.3 V and the measurement voltage value of the second measurement circuit 140 is 2.6 V, the transmission path 120 sets the average value of these to 2.45 V. A correction process is performed so as to output.

  When the semiconductor test apparatus 100 determines that the data of the voltage value of each signal has not deviated beyond a predetermined threshold as a result of the determination by the calibration content determination circuit 150 (NO in step S203), the calibration is not performed. The process is terminated as it is not necessary.

  As described above, in the semiconductor test apparatus 100 according to the present embodiment, the voltage value of the signal generated by the signal generator 110 and transmitted through the transmission path 120 is transmitted by the first and second measurement circuits 130 and 140. A process of measuring the voltage value of the signal transmitted through 120, and comparing the voltage value data of each of these signals by the calibration content determination circuit 150 to determine whether or not the difference is greater than a predetermined threshold value. Do. If it is determined that the difference is greater than or equal to the predetermined threshold, the feedback arithmetic circuit 160 calculates the average voltage value of the measurement voltage value of the first measurement circuit 130 and the measurement voltage value of the second measurement circuit 140. Then, the transmission path 120 is controlled so as to output these average voltages to the DUT.

  For this reason, the voltage values of the signals measured by the first and second measurement circuits 130 and 140 are compared to determine whether or not there is a divergence between the voltage values of the signals. The temperature change can be detected accurately using the characteristics of

  Further, when the temperature change occurs, the average value of the voltage value of each signal is calculated and corrected so that the voltage value of the signal approaches the voltage value at the time of occurrence in the signal generator 110 according to the temperature change. Can be corrected and properly calibrated.

[Other Embodiments]
In the above-described embodiment, two are provided using the first and second measurement circuits 130 and 140 that measure the voltage value of the signal. However, the present invention is not limited to this, and a plurality of three or more may be used. . In this case, the feedback arithmetic circuit 160 performs a process of correcting to the average value of the voltage value of each signal measured by each measurement circuit.

It is explanatory drawing which shows the structure of the semiconductor test apparatus of this embodiment. It is explanatory drawing which shows the temperature change characteristic of the measurement circuit of the semiconductor test apparatus of this embodiment. It is a flowchart which shows operation | movement of the semiconductor test apparatus of this embodiment. It is explanatory drawing which shows the structure of the semiconductor test apparatus in a prior art.

Explanation of symbols

100, 200 Semiconductor test equipment 110, 210 Signal generators 120, 220 Transmission paths 130, 140, 230 Measurement circuit 150 Calibration content determination circuit 160 Feedback arithmetic circuit 170, 240 Thermometer

Claims (3)

Signal generating means for generating a signal for output to the object under test;
A transmission path for transmitting the signal generated by the signal generating means;
A plurality of voltage measuring means for measuring a voltage value of a signal transmitted through the transmission path;
A semiconductor test apparatus, comprising: signal calibrating means for calibrating voltage values of signals transmitted through the transmission path signal based on voltage values of signals measured by the plurality of voltage measuring means. Signal generating means for generating a signal for output to the object under test;
A transmission path for transmitting the signal generated by the signal generating means;
First voltage measuring means for measuring a voltage value of a signal transmitted through the transmission path within a first range;
Second voltage measuring means for measuring a voltage value of a signal transmitted through the transmission path within a second range different from the first range;
Signal calibration means for calibrating the voltage value of the signal transmitted through the transmission path signal based on the voltage value of the signal respectively measured by the first and second voltage measurement means. Semiconductor test equipment. The semiconductor test apparatus according to claim 2,
The signal calibration means is
Voltage determination means for determining whether or not the voltage value of the signal measured by the first and second voltage measurement means is more than a preset threshold value;
Based on the average value of the voltage values of the signals measured by the first and second voltage measuring means when it is determined that the voltage judging means has deviated beyond a preset threshold as a result of the determination. A semiconductor test apparatus comprising voltage calibration means for calibrating a voltage value of a signal.

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