JP3074988B2 - IC tester - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an IC tester having a circuit for simultaneously measuring a plurality of samples, and more particularly to an IC tester for measuring an integrated circuit in which analog circuits and digital circuits are mixed. Thus, the present invention relates to a parallel measurement IC tester capable of synchronously controlling a plurality of analog measurement systems and simultaneously measuring a plurality of samples.

[0002]

2. Description of the Related Art In an IC tester for testing an integrated circuit in which an analog circuit and a digital circuit coexist, as shown in FIG.
1. A high-speed processing unit (array processor) 32 is connected by a control bus 22 and a high-speed data transfer bus 33. In the analog measurement system, conversion between analog and digital signals is performed by an (A / D, D / A) converter so that all signal processing in the apparatus can be replaced with numerical operation. In order to derive measurement results and the like, they are mutually connected to a high-speed data transfer bus 33.

When a test is performed in such an apparatus, for example, when signal processing is performed on an analog output signal of a sample under test, as shown in FIG.
First, the digital signal output from the A / D converter 34 is written to a storage circuit 35 incorporated in the analog measurement system 30, and then the high-speed data transfer bus 33 is written.
Is transferred to the high-speed arithmetic processing unit 32 via the CPU for processing. In this configuration, since the high-speed arithmetic processing unit 32 is expensive, a method of sharing the same with the entire IC tester has been adopted.

[0004]

The function of simultaneously measuring a plurality of samples in an IC tester or the like is a well-known technique at present. In consideration of the size of the device, particularly the cost of a high-speed processing device, for example, the measurement of a digital circuit performs a plurality of simultaneous measurements, and the measurement of an analog circuit measures one analog output of a plurality of DUTs. Measurement was performed by inputting the data to a test apparatus, and when the measurement was completed, the connection was switched to the next sample and the measurement was performed. In this method, the test time per measurement sample is T,
When the number of simultaneously measured samples is N, it takes T × N time, indicating that there is no point in performing the simultaneous measurement in the measurement of the analog circuit.

An object of the present invention is to provide an IC tester capable of simultaneously measuring a plurality of test samples and testing time when testing an integrated circuit in which an analog circuit and a digital circuit are mixed. For the purpose.

[0006]

In order to achieve this object, the present invention provides a processor dedicated to operation (digital processor).
A signal processor) 1, storage circuits 2 and 3 arranged in the address space of the dedicated processor 1, an A / D converter 4 for measuring the analog output of the sample and converting the measured value to a digital signal, D to apply analog signal
An analog measurement system 6 having an A / A converter 5 is prepared for the number of samples to be measured for simultaneous measurement, and an analog measurement system control signal 1A and a common analog measurement system control signal 1A are provided for each analog measurement system. And a pattern generator 10 for executing a pattern control of a digital measurement system which generates an interrupt signal 1B in the dedicated arithmetic processor 1 by a programmed micro code.

[0007]

According to the present invention, a processor dedicated to arithmetic operation is arranged in an analog measurement system, and an interrupt signal and a control signal are supplied by a micro code programmed from the digital measurement system, thereby providing a communication between the digital measurement system and the analog measurement system. Synchronization is enabled, and simultaneous measurement of multiple test samples is enabled.

[0008]

FIG. 1 is a block diagram of an apparatus for simultaneously measuring a plurality of samples under test according to the present invention. 1 is a processor dedicated to operation (digital signal processor), 2 and 3 are storage circuits arranged in the address space of the processor 1 dedicated to operation, 4 is a high-precision A / D converter, and 5 is high-precision D / A conversion. Instrument, 6 is an analog measurement system, 7-9 is 6
An analog measurement system having the same configuration as 10 is a pattern generator, 1
1 is a pattern storage circuit, 12 to 15 are paths for inputting the digital response of each test sample to an analog measurement system assigned to each test sample, 20 is a digital measurement system, 21
Is a control processing device, and 22 is a control bus.

The dedicated processors 1 arranged in each of the digital measurement systems 20 and 6 to 9 are connected to a control processing device 21 via a control bus 22. The control processor 21 sets test conditions for the 6 to 9 analog measurement systems and digital measurement systems via the control bus 22, transfers test patterns to the pattern storage circuit 11 and the like, and generates a test start trigger signal. It has a role of taking in test results from a plurality of measurement systems and performing processing.

The analog measuring systems 7 to 9 are composed of a processor dedicated to operation 1, storage circuits 2, 3, a high-precision A / D converter 4, and a high-precision D / A converter 5, as in the analog measuring system 6. I have. Here, the storage circuit 2 has an A / D converter 4
The digital value as the conversion result is stored and stored
Digital value input to D / A converter 5 is stored in path 3
Is done. By doing so, for example, a processor dedicated to arithmetic
The sample can be measured at a speed exceeding the processing speed of 1.
That is, the digital value converted by the A / D converter 4 is output.
The processing speed of the dedicated processor 1
If the output speed is higher than
The digital values are temporarily stored in the storage circuit 2 and the measurement of the sample is stopped.
At the time when the operation is stopped, the dedicated processor 1
Read the digital value stored in path 2 and
Data processing. Similarly, a D / A converter
5 is used to reduce the processing speed of the
If you want to operate at a speed exceeding
The digital value is stored in the storage circuit 3 from the processor 1 for
In this way, the D / A converter 5
To convert the total value. Analog measurement system 6-9
Is prepared for each of a plurality of test samples, and a high-precision A / D
The converter 4 outputs a high-precision D / A to the analog output of the test sample.
The converters 5 are each connected to an analog input of the test sample. In the signal processing in each analog measurement system, the A / D converter 4 and the D / A converter 5 perform analog-to-digital conversion so that the arithmetic dedicated processor 1 can perform the processing in place of numerical calculation. The digital signals of the A / D converter 4 and the D / A converter 5 are stored in the storage circuit 2,
Both the method of directly reading and writing to the memory 3 and the method of reading and writing to the storage circuits 2 and 3 via the dedicated processor are controlled by the dedicated processor 1 and can be selected.

The processor dedicated to arithmetic operation (digital signal processor) 1 arranged in the analog measurement systems 6 to 9 can be obtained at a low price due to the recent development of IC technology, and a circuit using the same can be obtained. Due to the degree of freedom of the configuration, it is possible to reduce the cost and size, which were difficult with the conventional IC tester. Furthermore, a high-speed processing unit (array processor) shared by the entire conventional IC tester
32, real-time processing of the analog measurement systems 6 to 9 synchronized with the digital measurement system 20 is enabled.

When a trigger signal for starting a test is generated from the control processing device 21, the pattern generator 10 sequentially reads out micro codes from the pattern storage circuit 11, and
A digital pattern is applied to a plurality of test samples while executing instructions written in microcode. In addition to the control instructions for the digital measurement system 20, control instructions for the analog measurement systems 6 to 9 are added to the micro code, and when the pattern generator executes the added instruction, the analog measurement systems 6 to 9 are shared. An analog measurement system control signal 1A and an interrupt signal 1B are generated. Note that microcode is used.
It is used for the following reasons. Sand
That is, a digital pattern is stored in the pattern storage circuit 11.
Because the microcode is stored,
Between the pattern to be processed and the processing by executing the micro code
The timing relationship between them becomes easier to understand. In addition, IC
Microcode and digital data for the user
All you have to do is create a special pattern.
It is free from the hassle of mounting a simple circuit.

Each of the dedicated processors 1 arranged in the analog measurement systems 6 to 9 decodes the contents of the analog measurement system control signal 1A in response to the interrupt signal 1B, and executes a process according to the contents. These two signals enable the analog measurement systems 6 to 9 to synchronize between the digital measurement system 20 and the analog measurement system and to simultaneously measure a plurality of test samples.

The micro code for controlling the analog measurement systems 6 to 9 includes, for example, an instruction to take in a digital response from a test sample through paths 12 to 15,
A / D converter 4 provided for analog measurement systems 6 to 9
And an instruction to generate a voltage in the D / A converter 5 are provided.

For example, when an instruction to capture a digital response from a test sample is issued, the analog measurement system 6
The computation dedicated processor 1 arranged in each of .about.9 fetches digital responses from each test sample from paths 12 to 15 which are input to analog measurement systems allocated to each test sample, and uses the digital responses fetched. , Real-time processing such as changing the output voltage of the D / A converter 5 can be controlled for each test sample.

Therefore, this point will be described in more detail. Up
A collection of analog and digital circuits
In an IC tester for testing integrated circuits, these circuits
While applying analog or digital signals
Measures log signals or bases on digital responses
Or perform data processing. Now, for example,
A / D conversion circuit built into the microcomputer
Below, "Built-in A / D converter"
Circuit ”) is considered. putter
The generator 10 is programmed in the pattern storage circuit 11.
Execute the instructions in the microcode
Digital pattern, and
Analog measurement system control signal 1A and interrupt signal 1
B is generated and sent to the processor 1 dedicated to operation. Calculation
Dedicated processor 1 is analog by interrupt signal 1B
The processing according to the contents of the measurement system control signal 1A is executed. This
Thus, the digital measurement system 20 and the analog measurement systems 6 to 9
Measurement while synchronizing. That is, the built-in A / D conversion
The timing of the conversion circuit sampling the analog value
In addition, the digital measurement system 20 applies a voltage to the D / A converter 5.
The instruction for generating
The processor 1 performs analog measurement from the digital measurement system 20
Based on system control signal 1A and interrupt signal 1B, D
The analog signal is output from the A / A converter 5 and the built-in A / D converter
Applied to the conversion circuit. Then, the built-in A / D conversion circuit
Convert an analog signal to a digital value and output it after a predetermined time.
This digital value is applied to paths 12-1 as described above.
5 to the analog measurement systems 6 to 9 respectively.
You. Therefore, the digital measuring system 20
In addition, the digital response from the test
Execute the instruction (described above) from. This day
In accordance with the instruction of the digital measurement system 20, the analog measurement system 6 to
9 are dedicated to the respective processors 1 through paths 12-15.
To obtain the digital value. A series of processing as described above
The microcode stored in the digital measurement system 20
The processor dedicated to operation 1
Is the processing of the digital measurement system 20 (digital pattern
Synchronized, etc. applied) (based on digital response
Process) can be performed in real time. What
After the measurement is completed, even when signal processing is performed on the acquired data, the data can be simultaneously processed by the dedicated processor 1 arranged in the analog measurement systems 6 to 9.

[0017]

According to the present invention, since the digital measurement system and the analog measurement system can be synchronized and simultaneous measurement of a plurality of test samples is possible, the test time can be greatly reduced as compared with the conventional system. There is an advantage that can be.

[Brief description of the drawings]

FIG. 1 is a configuration diagram of a parallel measurement mechanism in an IC tester according to one embodiment of the present invention.

FIG. 2 is a configuration diagram of an IC tester for measuring an integrated circuit in which an analog circuit and a digital circuit are mixed in the related art.

FIG. 3 is a diagram illustrating a measuring method in the related art when measuring an analog output of an integrated circuit in which an analog circuit and a digital circuit are mixed.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 Dedicated processor (digital signal processor) 2 Storage circuit arranged in the address space of dedicated processor 1 3 Storage circuit arranged in the address space of dedicated processor 1 4 High-precision A / D converter 5 High-precision D / A converter 6-9 Analog measurement system 10 Pattern generator 11 Pattern storage circuit 20 Digital measurement system 21 Control processor 22 Control bus

Claims (1)

(57) [Claims] A digital signal processor (1) and a first storage circuit which converts an analog output from a sample under test into a digital output and is arranged in an address space of the digital signal processor (1). A / D converter (4) stored in (2) and a second storage circuit arranged in the address space of the digital signal processor (1)
An analog measurement system (6) including a D / A converter (5) for converting the digital information stored in (3) into analog information and supplying the analog information to the sample under test, and a pattern storing a micro code. A storage circuit (11) and the micro-circuit read out from the pattern storage circuit (11).
A digital measurement system (20) including a pattern generator (10) for applying a digital pattern to the sample under test according to a code, wherein the pattern generator (10) is provided in the analog measurement system (6). An IC tester for supplying a control signal (1A) and an interrupt signal (1B) to a digital signal processor (1).