CN112865803A

CN112865803A - Compression method and device for SCAN vector in ATE device

Info

Publication number: CN112865803A
Application number: CN202011631766.1A
Authority: CN
Inventors: 陈永; 邬刚
Original assignee: Hangzhou Acceleration Technology Co ltd
Current assignee: Hangzhou Acceleration Technology Co ltd
Priority date: 2020-12-31
Filing date: 2020-12-31
Publication date: 2021-05-28

Abstract

The invention provides a compression method and equipment of SCAN vectors in ATE equipment, which comprises the following steps: step 1, traversing all vectors in a current latest SCAN vector set by taking a specified size as a unit so as to divide the SCAN vector set into a plurality of vector subsets with specified sizes; step 2, dividing the same vector subsets into the same category, and determining the number of the vector subsets under each category; step 3, sorting at least the categories according to the number, and determining a preset number of categories which are sorted at the top; step 4, removing the vector subsets of the determined categories from the SCAN vector set to update the SCAN vector set; step 5, establishing a mapping relation between the determined category and the encoded data, and replacing the vector subset under the category with the encoded data based on the mapping relation; encoding data smaller than the data size of the vector subset; and 6, replacing the traversal size and repeatedly executing the steps 1-5 to finish compression. The compression is performed by establishing a mapping between the subset of vectors and the encoded data.

Description

Compression method and device for SCAN vector in ATE device

Technical Field

The present invention relates to the field of SCAN vector compression technology in ATE equipment, and in particular, to a method and an apparatus for compressing SCAN vectors in ATE equipment.

Background

ATE (Automatic Test Equipment) is a system for automatically testing integrated circuits by using computers and dedicated Equipment. ATE is used to test the integrity of the function and performance of an integrated circuit and is an important device in ensuring the quality of the integrated circuit during the manufacturing process.

The test signals of the ATE are synthesized from test timing and test vectors, the test timing defining signal periods (T) and test waveforms (Wave) of the device under test and corresponding Edge (Edge) time points of each test waveform. The test vector is a code set for controlling a tester to generate a signal waveform required by a chip to be tested and judging whether the response of the test chip is correct, and the SCAN vector is the most common test vector in the digital integrated circuit test. With the continuous development of integrated circuits, the integration scale and complexity of the integrated circuits are increasing, so that the test complexity of the integrated circuits is also increasing, and the SCAN vectors required for testing the integrated circuits are also increasing. The method not only continuously increases the loading time of the SCAN vectors, but also continuously increases the requirements on the storage space of the SCAN vectors, thereby not only bringing great challenges to automatic test equipment, but also continuously reducing the efficiency of integrated circuit test and continuously increasing the cost.

Thus, there is a need for a solution to the problems of the prior art.

Disclosure of Invention

In view of the above, the present invention provides a method and an apparatus for compressing SCAN vectors in ATE equipment. In the scheme, the SCAN vector is converted into smaller coded data, so that data compression of the SCAN vector is realized, and the data volume and the data storage space of the SCAN vector are reduced.

Specifically, the invention provides a compression method of SCAN vectors in ATE equipment, which comprises the following steps:

step 1, traversing all vectors in a current latest SCAN vector set by taking a specified size as a unit so as to divide the SCAN vector set into a plurality of vector subsets with specified sizes;

step 2, dividing the same vector subsets into the same category, and determining the number of the vector subsets under each category;

step 3, sorting the categories according to the number of the categories, and determining a preset number of categories which are sorted at the top;

step 4, the vector subset of the determined category is removed from the SCAN vector set so as to update the SCAN vector set;

step 5, establishing a mapping relation between the determined category and the encoded data, so as to replace the vector subset under the category with the encoded data based on the mapping relation; the encoded data is smaller than a data size of the subset of vectors;

step 6, repeating the steps 1-5 to complete the compression; wherein the larger the number of repetitions, the smaller the specified size.

In a specific embodiment, the encoded data is binary data.

In a specific embodiment, the encoded data consists of type codes and dictionary codes; wherein the type code is used to identify the category to which the subset of vectors corresponds; the dictionary codes are used for identifying different vector subsets under the same type code.

In a particular embodiment, said preset number is equal to or less than 2^K(ii) a And K is the bit number of the dictionary code.

In a specific embodiment, the size of the type code is 3 bits; the size of the dictionary code is 6 bits; the preset number is less than or equal to 64.

In a specific embodiment, the set of SCAN vectors includes a plurality of vectors.

In a specific embodiment, the method further comprises the following steps:

determining other vectors in the SCAN vector set except the vector subset under the determined category;

marking the other vectors by taking a preset bit as a unit and then storing the other vectors and the coded data together; wherein the preset bits are smaller than the number of bits of the minimum Nth encoded data.

The embodiment of the present invention further provides a device for compressing SCAN vectors in ATE devices, including:

the traversing module is used for traversing all vectors in the current latest SCAN vector set by taking the specified size as a unit so as to divide the SCAN vector set into a plurality of vector subsets with the specified sizes;

the classification module is used for dividing the same vector subsets into the same category and determining the number of the vector subsets under each category;

the sorting module is used for sorting the categories according to the number of the categories and determining the preset number of categories which are sorted at the top;

an updating module, configured to remove the vector subset of the determined category from the SCAN vector set to update the SCAN vector set;

the mapping module is used for establishing a mapping relation between the determined category and the encoding data so as to replace the vector subset under the category with the encoding data based on the mapping relation; the encoded data is smaller than a data size of the subset of vectors;

the iteration module repeatedly executes the traversal module-mapping module to complete compression; wherein the larger the number of repetitions, the smaller the specified size.

In a specific embodiment, the encoded data is binary data.

Therefore, the scheme has the following technical effects:

in the scheme of the application, the SCAN vectors are traversed, the vector subsets with the largest number of preset numbers are continuously selected, the mapping relations between the vector subsets with different types and the coded data are established, and the coded data with the mapping relations are smaller than the vector subsets, so that data compression is realized by converting the SCAN vectors into the coded data, and the data volume and the storage space of the data are reduced.

Drawings

In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings needed to be used in the embodiments will be briefly described below, it should be understood that the following drawings only illustrate some embodiments of the present invention and therefore should not be considered as limiting the scope, and for those skilled in the art, other related drawings can be obtained from the drawings without inventive effort.

FIG. 1 is a block diagram of a conventional ATE semiconductor tester;

FIG. 2 is a diagram illustrating conventional vectors involved in a method for compressing SCAN vectors in ATE equipment according to an embodiment of the present invention;

FIG. 3 is a schematic diagram of SCAN vectors in a compression method for SCAN vectors in ATE equipment according to an embodiment of the present invention;

fig. 4 is a schematic diagram illustrating the meaning of SCAN vectors of each channel in a method for compressing SCAN vectors in ATE equipment according to an embodiment of the present invention;

FIG. 5 is a diagram illustrating waveforms generated by SCAN vectors in a method for compressing SCAN vectors in ATE equipment according to an embodiment of the present invention;

FIG. 6 is a schematic diagram of SCAN vectors in a compression method for SCAN vectors in ATE equipment according to an embodiment of the present invention;

FIG. 7 is a flowchart illustrating a method for compressing SCAN vectors in ATE equipment according to an embodiment of the present invention;

FIG. 8 is a diagram illustrating a format of encoded data in a method for compressing SCAN vectors in ATE devices according to an embodiment of the present invention;

FIG. 9 is a diagram illustrating mapping in a method for compressing SCAN vectors in ATE equipment according to an embodiment of the present invention;

FIG. 10 is a flowchart illustrating a method for compressing SCAN vectors in ATE equipment according to an embodiment of the present invention;

FIG. 11 is a block diagram of a SCAN vector compression apparatus for ATE equipment according to an embodiment of the present invention;

fig. 12 is a schematic diagram of a compressing apparatus for SCAN vectors in an ATE apparatus according to an embodiment of the present invention.

Detailed Description

Various embodiments of the present invention will be described more fully hereinafter. The invention is capable of various embodiments and of modifications and variations therein. However, it should be understood that: there is no intention to limit various embodiments of the invention to the specific embodiments of the invention herein, but rather, the invention is to cover all modifications, equivalents, and/or alternatives falling within the spirit and scope of various embodiments of the invention.

The terminology used in the various embodiments of the invention is for the purpose of describing particular embodiments only and is not intended to be limiting of the various embodiments of the invention. As used herein, the singular is intended to include the plural as well, unless the context clearly indicates otherwise. Unless otherwise defined, all terms (including technical and scientific terms) used herein have the same meaning as commonly understood by one of ordinary skill in the art to which various embodiments of the present invention belong. The terms (such as those defined in commonly used dictionaries) should be interpreted as having a meaning that is consistent with their meaning in the context of the relevant art and will not be interpreted in an idealized or overly formal sense unless expressly so defined herein in various embodiments of the present invention.

Example 1

As shown in fig. 1, ATE generally consists of a host computer and a dedicated test equipment, and it usually needs four processes of test programming, test vector generation, test vector loading, and test execution for testing an integrated circuit. For digital integrated circuit testing, the test execution process is mainly the operation process of the test vector;

fig. 2 shows a data structure of a conventional vector, where the test vector is composed of the conventional vector and SCAN vectors, where the number of channels is 16 for example, and a SCAN vector set of 16 channels is shown in fig. 3, where each channel is a channel of an ATE connected to an integrated circuit, for example, there are 3 lines connected to an integrated circuit to be tested, and each line corresponds to 1 channel, that is, there are 3 channels.

Wherein each channel data in each SCAN vector is 3 bits, and possible data of the SCAN vector and the meaning represented by the data are shown in FIG. 4; for example, the data is 000, which means that the output is high; for another example, the class is 001, which means that the output is low.

As can be seen from the format of the SCAN vector, the content of the SCAN vector comprises the waveform period, the number of edges and the edge time information, the waveform period which is usually expressed is fixed, the number of the edges is single, and the edge time point is fixed. The SCAN vector is used for carrying out scanning output driving and input comparison on an interface of a digital chip, the number of the vectors is very large, and therefore the loading time of the SCAN vector is very long and the storage space is very large. However, the test throughput determined by the test time of the semiconductor chip and the test cost are determined to some extent, and the vector storage space of the general ATE tester is limited, so if the vector space is upgraded, high-end test equipment must be upgraded, the chip test cost is further increased, and the SCAN vector is effectively compressed to be rigid. And just because the SCAN vector is used for carrying out scanning type output driving and input comparison on an interface of a digital chip, a large amount of information and data redundancy exists, and the possibility is provided for compressing vector subsets.

Specifically, the waveform generated by the SCAN vector is shown in fig. 5, and the SCAN vector generating the waveform shown in fig. 5 is shown in fig. 6, it can be seen from fig. 6 that a large amount of information repetition exists in the content of the SCAN vector, and the content has a certain regularity according to the characteristics of the channel waveform, thereby providing a theoretical basis for compressing the SCAN vector.

Therefore, according to the characteristics of SCAN vector channel binding, waveform repetition and the like, the vector subset with the specified size is designed to analyze the vector repeatability, and the high-bit-width data vectors with a large number of repetition times are subjected to low-bit-width data dictionary coding, so that the purpose of vector compression is achieved.

Specifically, the embodiment of the present invention discloses a method for compressing SCAN vectors in ATE equipment, as shown in fig. 7, including:

the SCAN vector set includes a plurality of vectors. Specifically, as shown in fig. 6, the vector set of SCAN is a vector set of SCAN, which includes 16 channels, which are respectively named PIN _1, PIN _2, PIN _15, and PIN _ 16; the vectors are sequentially ordered according to time sequence, for example, as shown in fig. 6, taking PIN _1 as an example, the vector includes 15 time periods, and each time period corresponds to one vector, so that 15 vectors are total. Specifically, the size of each vector is 3 bits.

Specifically, the operation of traversing in a unit of a specified size, for example, in a unit of a specified size of 24 bits, that is, the size of 8 vectors, in this case, the operation of traversing may start from time period 1 of PIN _1, and take time period 1 of PIN _8 as a unit, and according to time periods from 1 to 15, each time period traverses from left to right in turn, and divides the SCAN vector set into 30 vector subsets of 24 bits; of course, the traversal operation can also be performed from the time period 1 of the PIN _1 to the time period 8 of the PIN _1 as a unit, and from the top to the bottom, from the PIN _1 to the PIN _ 16; in addition, the traversal operation may also be performed, for example, from time period 1 of PIN _1, to time period 1 of PIN _2, time period 1 of PIN _3, time period 1 of PIN _4, and then to time period 2 of PIN _1, to time period 2 of PIN _2, time period 2 of PIN _3, and time period 2 of PIN _ 4.

The specific traversal pattern can be varied and is not limited to the specific patterns.

specifically, for example, the designated size is 12 bits, and the traversal manner is from time period 1 of PIN _1, to time period 1 of PIN _2, to time period 1 of PIN _3, and to time period 1 of PIN _4, so that the corresponding vector subset is [ 001, 001 ], which is named as vector subset 1; specific other vector subsets are generated by means of traversal, for example, vector subsets of [ 000, 001, 000, 001 ] may also be named as vector subset 2, in this case, the two vector subsets are taken as an example for illustration, and then the number of vector subsets 1 and the number of vector subsets 2 need to be determined respectively, and the number of vector subsets 3 may also be other vector subsets, and the like.

the number of the individual categories can be determined in step 2, wherein the categories are sorted from most to least, and the top category is selected, for example, the top 24 categories are selected.

after step 3 is executed, the vector subset of the determined category is removed to obtain the SCAN vector set so as to update the SCAN vector set, and after a specific removing operation, the SCAN vector set can also be in a format shown in fig. 6, and only the removed portion is left empty.

in a specific embodiment, the encoded data is binary data. Combinations can thus be formed by the variation of each bit in the binary data for mapping different vector subsets.

Further, the coded data consists of type codes and dictionary codes; wherein the type code is used to identify the category to which the subset of vectors corresponds; the dictionary codes are used for identifying different vector subsets under the same type code. The preset number is equal to or less than 2^K(ii) a And K is the bit number of the dictionary code.

In a specific embodiment, as shown in fig. 8, the size of the type code is 3 bits; the size of the dictionary code is 6 bits; the preset number is less than or equal to 64. A specific type code is used to identify the category of the subset of vectors.

Further, in one embodiment, for example, the size of the type code is 3 bits; the characterThe size of the code is 6 bits; the specified number is 64. In this case, the type code has 3 bits, and its possible combination is 2³The dictionary code has a size of 6 bits, in which case the specified number is equal to or less than 2^K(ii) a And K is the bit number of the dictionary code. Taking a dictionary code of 6 bits as an example, the corresponding combinations are 64, that is, the preset number needs to be less than or equal to 2^KTo avoid spillage.

Specifically, in one embodiment, for example, traversal may be performed in units of 48 bits, and the determined vector subset with the size of 48 bits is replaced with encoded data to complete the first compression; at the second time, since the vectors in the SCAN vector set are reduced and the size of the corresponding unit is also required to be reduced, the same operation can be performed in units of 24 bits, for example; for the third time, the unit is reduced again, for example, the operation is performed in units of 12 bits, and the third compression is performed. The specific encoded data will be smaller than the size of the subset of vectors and thus the size of the entire set of SCAN vectors can be reduced. If the encoded data may be 8 bits, the compression ratio may be 1:6 in the first compression, 1:3 in the second compression, 1:2 in the third compression,

specifically, as shown in fig. 8, the encoded data may be 8 bits, where the upper 2 bits is a type code and the lower 6 bits is a dictionary code. When dictionary coding is carried out by taking 48 bits as a unit, the type code corresponding to the vector subset can be 2' b00, the number of dictionaries is 64, and the compression ratio is 1: 6;

when dictionary coding is carried out by taking 24 bits as a unit, the type code corresponding to the vector subset is 2' b01, the number of dictionaries is 64, and the compression ratio is 1: 3;

when dictionary coding is carried out by taking a 4-channel vector subset (16bit) as a unit, the type code corresponding to the vector subset is 2' b10, the number of dictionaries is 64, and the compression ratio is 1: 2;

thus, the dictionary code mapping situation is obtained as shown in fig. 9, the source code data in the table in fig. 9 is a compressed dictionary table created by performing repeated statistics on the SCAN vector subsets in units of 48 bits, 24 bits and 12 bits, sorting according to the number of repeated times of the data according to the result obtained by the statistics, and filling 64 data before the repeated times are sorted into the corresponding types in the dictionary table.

Further, as shown in fig. 10, after the above compression, the SCAN vector can be effectively compressed, but considering that there may be other parts of the SCAN vector besides the compressed part, the scheme further includes:

Specifically, other vectors are not compressed, and may be stored after the original data is added with a type code, for example, 2' b11, so that the compression ratio is 4:3, although this portion increases the data amount to some extent, the overall data amount is compressed, and the integrity of the whole SCAN vector can be ensured, which is convenient for the subsequent decompression operation.

The scheme provides a compression method. The SCAN vector subset can be effectively compressed, and the maximum compression ratio of the SCAN vector subset is up to 1:6 by taking the example as an example, so that the loading time of the SCAN vectors in the test process can be greatly shortened, and the capacity required by SCAN vector storage can be greatly reduced. The SCAN vector compression method adopts a typical multi-type dictionary compression algorithm according to the channel repetition characteristics of the SCAN vector subsets, the compression process is simple and easy to realize, the length of the compressed data can be fixed 8 bits, only 8-bit dictionary codes are replaced by source codes in the decompression process, the decompression is simple and has no time delay, the lower the requirement on reading and executing the vector of an ATE tester is, the better the compression and decompression method can perfectly fit the requirement.

Example 2

Embodiment 2 of the present invention further discloses a compression device for SCAN vectors in ATE devices, as shown in fig. 11, including:

the traversing module 201 is configured to traverse all vectors in a current latest SCAN vector set by using a specified size as a unit, so as to divide the SCAN vector set into a plurality of vector subsets of specified sizes;

the classification module 202 is configured to classify the same vector subsets into the same category, and determine the number of the vector subsets in each category;

the sorting module 203 is configured to sort the categories according to the number of the categories, and determine a preset number of categories which are sorted at the top;

an updating module 204, configured to remove the vector subset of the determined category from the SCAN vector set to update the SCAN vector set;

a mapping module 205, configured to establish a mapping relationship between the determined category and encoded data, so as to replace the vector subset under the category with the encoded data based on the mapping relationship; the encoded data is smaller than a data size of the subset of vectors;

the iteration module 206 repeatedly executes the traversal module 201-mapping module 205 to complete compression; wherein the larger the number of repetitions, the smaller the specified size.

Specifically, a compression device of SCAN vectors in ATE devices may be a Central Processing Unit (CPU) of a main control board as shown in fig. 12; since there is compression, when the SCAN vector needs to be called in the actual application process, decompression needs to be performed, and this part can be performed by an FPGA (Field Programmable Gate Array) in the service board.

In a specific embodiment, the encoded data is binary data.

In a specific embodiment, the method further comprises the following steps: a processing module, configured to determine other vectors in the SCAN vector set except for the vector subset under the determined category;

Those skilled in the art will appreciate that the figures are merely schematic representations of one preferred implementation scenario and that the blocks or flow diagrams in the figures are not necessarily required to practice the present invention. Those skilled in the art will appreciate that the modules in the apparatus in the implementation scenario may be distributed in the apparatus in the implementation scenario according to the description of the implementation scenario, or may be located in one or more apparatuses different from the present implementation scenario with corresponding changes. The modules of the implementation scenario may be combined into one module, or may be further split into a plurality of sub-modules. The above-mentioned invention numbers are merely for description and do not represent the merits of the implementation scenarios. The above embodiments of the present invention are merely exemplary embodiments, but the present invention is not limited thereto, and any variations that can be considered by those skilled in the art are intended to fall within the scope of the present invention.

Claims

1. A compression method for SCAN vectors in ATE equipment is characterized by comprising the following steps:

step 4, removing the vector subset of the determined category from the SCAN vector set so as to update the SCAN vector set;

2. The method of claim 1, wherein the encoded data is binary data.

3. A method according to claim 1 or 2, wherein the encoded data consists of type codes and dictionary codes; wherein the type code is used to identify the category to which the subset of vectors corresponds; the dictionary codes are used for identifying different vector subsets under the same type code.

4. The method of claim 3, wherein the predetermined number is equal to or less than 2^K(ii) a And K is the bit number of the dictionary code.

5. The method of claim 3, wherein the type code is 3 bits in size; the size of the dictionary code is 6 bits; the preset number is less than or equal to 64.

6. The method of claim 1, wherein the set of SCAN vectors contains a plurality of vectors.

7. The method of claim 1, further comprising:

8. An apparatus for compressing SCAN vectors in ATE equipment, comprising:

9. The apparatus of claim 8, wherein the encoded data is binary data.

10. The apparatus of claim 8 or 9, wherein the encoded data consists of type codes and dictionary codes; wherein the type code is used to identify the category to which the subset of vectors corresponds; the dictionary codes are used for identifying different vector subsets under the same type code.