Electromigration serial test system and method

Abstract

The invention discloses an electromigration serial test system and method, the system comprises a constant current source, a resistance test device, a switch array and a processing and control module, the switch array comprises a first main switch, a second main switch, a plurality of test switches and a plurality of short circuit switches; the constant current source is connected with a plurality of test samples which are connected in series through the first main switch and loads current stress to the test samples; the resistance test equipment is connected in parallel with the plurality of test samples through a second main switch, and collects resistance data of each test sample; the plurality of test switches are respectively connected between the resistance test equipment and the test sample; and the processing and control module is used for sequentially testing the resistors of the test samples by controlling the switch array, judging the failed test samples according to the resistance data, and controlling the plurality of short-circuit switches to short-circuit the failed test samples. The method can greatly reduce the use number of electromigration test equipment, effectively improves the test efficiency, and reduces the time and economic cost.

Description

Technical Field

[0001] The invention belongs to the field of reliability testing, and in particular relates to an electromigration serial testing system and method. Background Art

[0002] Electromigration test is one of the important test methods to evaluate the reliability of device interconnection in electronic and electrical products. The electromigration test data of the sample structure is of great significance for supporting the reliability design of electronic and electrical products. However, electromigration test usually needs to be carried out under a variety of temperature and current coupling conditions, and multiple groups of sample tests need to be carried out under each set of test conditions to obtain the mean or distribution value of the sample test life. Therefore, a large number of current stress loading equipment and resistance test recording equipment are required. This test generally has problems such as long test time, a large number of test equipment, and multiple manual intervention or resets during the test process, which leads to low test efficiency and high time and economic costs.

[0003] In order to achieve the purpose of reducing the number of equipment used, the existing technology uses multi-channel current stress loading equipment (such as a constant current power supply with multi-channel output function) and multi-channel resistance test recording equipment (such as a multimeter with multi-channel test function) to carry out electromigration testing. Each electromigration test sample needs to occupy an independent channel in the current stress loading device for current loading, and needs to occupy an independent channel in the resistance test recording device for resistance testing. The resistance test recording device feeds back the collected resistance data to the background system to determine whether the sample has failed.

[0004] This solution of the prior art mainly realizes partial integration of the test system by adopting equipment with multi-channel output and test recording, thereby achieving the purpose of reducing the number of equipment used. However, the price of multi-channel output and test recording equipment is relatively expensive, and the number of output and test channels is very limited, which still cannot meet the test needs of a large number of samples in electromigration tests. For example, three different temperatures and current stress couplings need to correspond to 9 groups of different electromigration test conditions. 12 samples are tested under a single group of test conditions, and a total of 108 samples need to be tested. Using the common 3-channel output function constant current power supply and 3-channel resistance test recording equipment in the market, 36 multi-channel current stress loading devices and 36 multi-channel resistance test recording devices are still required to carry out the above tests simultaneously. Summary of the invention

[0005] The purpose of the present invention is to provide an electromigration serial test system and method, which can significantly reduce the number of electromigration test equipment used, effectively improve test efficiency, and reduce time and economic costs.

[0006] In order to achieve the above-mentioned object, one aspect of the present invention provides an electromigration serial test system, comprising a constant current source, a resistance test device, a switch array, and a processing and control module, wherein the switch array comprises a first main switch, a second main switch, a plurality of test switches, and a plurality of short-circuit switches; The constant current source is connected to a plurality of test samples connected in series through a first main switch, and is used to apply current stress to the test samples, so that all the test samples are tested under the same current stress; The resistance testing device is connected in parallel with a plurality of test samples through a second main switch, and is used to collect resistance data of each test sample, and feed the collected resistance data back to the processing and control module; A plurality of test switches are respectively connected between the resistance test device and the plurality of test samples, and are used to control the connection between the resistance test device and the corresponding test samples; a plurality of short-circuit switches are respectively directly connected between the resistance test device and the corresponding test switches, and are used to control the short circuit of the corresponding test samples; The processing and control module is used to load current stress on the test sample by controlling the first main switch, and to test the resistance of the test samples in sequence by controlling the second main switch and multiple test switches, to determine the failed test samples according to the resistance data, and to control multiple short-circuit switches to short-circuit the failed test samples.

[0007] Preferably, each test switch includes a positive switch and a negative switch, respectively, multiple positive switches are respectively connected between the positive pole of the resistance testing equipment and the corresponding test samples, multiple negative switches are respectively connected between the negative pole of the resistance testing equipment and the corresponding test samples, and multiple short-circuit switches are respectively directly connected between each positive switch and the corresponding negative switch.

[0008] Preferably, the processing and control module is used to control multiple test switches and multiple short-circuit switches to perform multiple resistance tests on each test sample, compare the resistance data obtained from each resistance test after the first one with the resistance data obtained from the first resistance test, and determine whether the test sample has failed by judging whether the resistance increase exceeds a set threshold.

[0009] Another aspect of the present invention provides an electromigration serial test method, which uses the above electromigration serial test system to perform an electromigration test, comprising: Step S1: multiple test samples to be tested are connected in series, the processing and control module controls the first main switch to be closed, current stress is applied to the test samples through a constant current source, and the second main switch is controlled to be closed to start the electromigration test; Step S2: Control the test switch of the first sample to be closed, test and obtain the first resistance data of the first sample, and feed it back to the processing and control module. After a specified interval, control the test switch of the first sample to be opened, and the test switch of the second sample to be closed, test and obtain the first resistance data of the second sample, and feed it back to the processing and control module. By analogy, test and obtain the first resistance data of all samples, and feed it back to the processing and control module. Step S3: Control the test switch of the first sample to close, test again to obtain the current resistance data of the first sample, and feed it back to the processing and control module, the processing and control module compares the current resistance data of the first sample with the first resistance data to determine whether the first sample has failed: when the current resistance data of the first sample increases by more than a set threshold value compared with the first resistance data, it is determined that the first sample has failed, the processing and control module controls the test switch of the first sample to open, and controls the short-circuit switch of the first sample to close, so that the first sample is short-circuited and exits the electromigration test; when the current resistance data of the first sample does not increase by more than a set threshold value compared with the first resistance data, it is determined that the first sample has not failed; after a specified interval time, and so on, the current resistance data of all samples are obtained in turn, and fed back to the processing and control module for failure determination; Step S4: Repeat step S3 until the processing and control module determines that all test samples have failed, disconnects the first main switch and the second main switch, and ends the electromigration test.

[0010] Preferably, the prescribed interval time is 10s or 20s, and the set threshold is 10% or 20%.

[0011] The electromigration serial testing system and method according to the above aspects of the present invention can significantly reduce the number of electromigration test equipment used, effectively improve test efficiency, and reduce time and economic costs. BRIEF DESCRIPTION OF THE DRAWINGS

[0012] In order to more clearly illustrate the technical solution of the present invention, the following briefly introduces the drawings used in the description of the embodiments of the present invention. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative work: Figure 1 It is a structural schematic diagram of an electromigration serial test system according to an embodiment of the present invention. DETAILED DESCRIPTION

[0013] In order to make the purpose, technical solution and advantages of the present invention clearer, the technical solution of the present invention will be clearly and completely described below in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0014] An embodiment of the present invention provides an electromigration serial test system. Figure 1 As shown, the electromigration serial test system of the embodiment of the present invention includes a constant current source, a resistance test device, a switch array, and a processing and control module. Among them, the constant current source is mainly used to load a stable current stress to the electromigration test sample, and the resistance test device is mainly used to collect the resistance data of the electromigration test sample, and feed the collected data back to the processing and control module. The processing and control module controls the switch array to realize the sequential testing of the resistance of the serial test samples according to the determination of the resistance data, and short-circuits the failed samples to ensure that other serial samples continue to be tested. In one embodiment, the processing and control module controls multiple test switches and multiple short-circuit switches to perform multiple resistance tests on each test sample, compares the resistance data obtained from each resistance test after the first time with the resistance data obtained from the first resistance test, and determines whether the test sample fails by judging whether the resistance increase exceeds the set threshold value. In the case of failure, the failed sample is short-circuited.

[0015] The switch array controlled by the processing and control module mainly includes an overall switch part, a test switch part and a short-circuit switch part. Among them, the overall switch part includes a first main switch (total 1) and a second main switch (total 2), which are respectively used to control the connection between the constant current source and the test sample, and the resistance test equipment and the test sample. The constant current source is connected to a plurality of test samples connected in series through the first main switch, and is used to load current stress on the test samples, so that all test samples are tested under the same current stress. The resistance test equipment is respectively connected in parallel with a plurality of test samples through the second main switch, and is used to collect resistance data of each test sample, and feed the collected resistance data back to the processing and control module.

[0016] The test switch part includes a plurality of test switches, which are respectively connected between the resistance test device and the plurality of test samples, and are used to control the resistance test connection between the resistance test device and the corresponding test samples. The short-circuit switch part includes a plurality of short-circuit switches, which are respectively directly connected between each test switch and the resistance test device, and are used to control the corresponding test sample to short-circuit.

[0017] In one embodiment, each test switch includes a positive switch and a negative switch, respectively. Multiple positive switches are respectively connected between the positive pole of the resistance testing device and the corresponding test samples, multiple negative switches are respectively connected between the negative pole of the resistance testing device and the corresponding test samples, and multiple short-circuit switches are respectively directly connected between each positive switch and the corresponding negative switch.

[0018] Specifically, Figure 1 As shown, the test switch part includes the positive switch (positive 1) and negative switch (negative 1) of the first sample (sample 1), the positive switch (positive 2) and negative switch (negative 2) of the second sample (sample 2), ..., the positive switch (positive n) and negative switch (negative n) of the nth sample (sample n), which respectively correspond to the resistance test connections of control sample 1, sample 2...sample n. The short-circuit switch part includes the short-circuit switch (short 1) of the first sample (sample 1), the short-circuit switch (short 2) of the second sample (sample 2), ..., the short-circuit switch (short n) of the nth sample (sample n), and when the test sample fails, the control samples 1, sample 2, ..., sample n are short-circuited and connected respectively.

[0019] The embodiment of the present invention further provides an electromigration serial test method, which uses the electromigration serial test system of the embodiment of the present invention to perform an electromigration test. The electromigration serial test method of the embodiment of the present invention includes the following steps S1 to S4.

[0020] In step S1, the electromigration test sample to be tested is connected to Figure 1 In the electromigration serial test system shown, all the test samples to be tested are connected in series, the processing and control module controls the first main switch to be closed, and the current stress is applied to the test samples connected in series through a constant current source, so that all the test samples are tested under the same current stress. According to the electromigration test conditions, a constant output current is set in the constant current source, and the second main switch is controlled to be closed to start the electromigration test. In this step, the switch array is initialized by the processing and control module, and all switches except the total 1 and total 2 switches are closed, and all other switches are in the open state.

[0021] In one embodiment, a program can be pre-set in the processing and control module to control the switch array to implement an automated test function. The program sets a test interval t (e.g., 10s or 20s) during the resistance test and a resistance change threshold (e.g., 10% or 20%) for determining whether the test sample has failed.

[0022] In step S2, the positive 1 and negative 1 switches are controlled to be closed, the first resistance data R11 of sample 1 is obtained through testing, and the resistance data R11 is fed back to the processing and control module. After an interval t, the test program controls the positive 1 and negative 1 switches to be disconnected, and the positive 2 and negative 2 switches to be closed, the first resistance data R12 of sample 2 is obtained through testing, and the resistance data is fed back to the processing and control module. By analogy with this method, the first resistance data R11, R12...R1n of all test samples are obtained through testing and fed back to the processing and control module.

[0023] In step S3, after the first resistance test is completed, according to the above steps, the positive 1 and negative 1 switches are continued to be controlled to be closed, and the second resistance data R21 (current resistance data) of sample 1 is obtained by test, and the resistance data is fed back to the processing and control module. The processing and control module compares R21 with R11 to determine whether the test sample 1 fails: when the increase (resistance increase) of R21 compared with R11 does not exceed the set threshold value (for example, 10% or 20%), it is determined that the test sample 1 has not failed. After the interval t, the second resistance data R22, R23, and R2n of sample 2, sample 3, and sample n are obtained in sequence by analogy in this way, and the resistance data are fed back to the processing and control module for failure determination; when R21 increases more than the set threshold value compared with R11, it is determined that sample 1 fails, and the processing and control module controls the positive 1 and negative 1 switches to be disconnected, and controls the short 1 switch to be closed. At this time, due to the closure of the short 1 switch, sample 1 is short-circuited, and the test sample 1 automatically exits the electromigration test, and the resistance test process no longer tests the resistance data of sample 1, and other test samples continue to maintain the constant current test.

[0024] In step S4, by analogy with this method, step S3 is repeated until the processing and control module determines that all test samples have failed, and the first main switch and the second main switch are disconnected, and the electromigration test is completely completed.

[0025] To summarize, the electromigration serial test system and method of the embodiments of the present invention perform current stress serial loading on multiple test samples through a constant current source, and realize sequential testing of the resistance of the test samples and short-circuiting of failed samples by controlling the switch array, thereby ensuring that other serial test samples continue to be tested. The electromigration test can be carried out under the condition of using only a single-channel current stress loading device and a resistance test recording device, which can greatly reduce the number of electromigration test equipment used, effectively improve the test efficiency, reduce time and economic costs, and provide a new set of solutions for electromigration reliability evaluation, which has good engineering application value and huge economic and social benefits.

[0026] The above description is only by way of illustration of certain exemplary embodiments of the present invention. It is undoubted that those skilled in the art can modify the described embodiments in various ways without departing from the spirit and scope of the present invention. Therefore, the above drawings and descriptions are illustrative in nature and should not be construed as limiting the scope of protection of the claims of the present invention.

Claims

1. An electromigration serial test system, characterized in that: It includes a constant current source, a resistance testing device, a switch array, and a processing and control module, wherein the switch array includes a first main switch, a second main switch, a plurality of test switches, and a plurality of short-circuit switches; The constant current source is connected to a plurality of test samples connected in series through a first main switch, and is used to apply current stress to the test samples, so that all the test samples are tested under the same current stress; The resistance testing device is connected in parallel with a plurality of test samples through a second main switch, and is used to collect resistance data of each test sample, and feed the collected resistance data back to the processing and control module; A plurality of test switches are respectively connected between the resistance test device and the plurality of test samples, and are used to control the connection between the resistance test device and the corresponding test samples; a plurality of short-circuit switches are respectively directly connected between the resistance test device and the corresponding test switches, and are used to control the short circuit of the corresponding test samples; The processing and control module is used to load current stress on the test sample by controlling the first main switch, and to test the resistance of the test samples in sequence by controlling the second main switch and multiple test switches, to determine the failed test samples according to the resistance data, and to control multiple short-circuit switches to short-circuit the failed test samples.

2. The system according to claim 1, characterized in that Each test switch includes a positive switch and a negative switch. Multiple positive switches are respectively connected between the positive pole of the resistance testing equipment and the corresponding test samples. Multiple negative switches are respectively connected between the negative pole of the resistance testing equipment and the corresponding test samples. Multiple short-circuit switches are respectively directly connected between each positive switch and the corresponding negative switch.

3. The system according to claim 1 or 2, characterized in that: The processing and control module is used to control multiple test switches and multiple short-circuit switches to perform multiple resistance tests on each test sample, compare the resistance data obtained from each resistance test after the first one with the resistance data obtained from the first resistance test, and determine whether the test sample has failed by judging whether the resistance increase exceeds a set threshold.

4. An electromigration serial testing method, characterized in that: The electromigration serial test system according to any one of claims 1 to 3 is used to perform an electromigration test, comprising: Step S1: multiple test samples to be tested are connected in series, the processing and control module controls the first main switch to be closed, current stress is applied to the test samples through a constant current source, and the second main switch is controlled to be closed to start the electromigration test; Step S2: Control the test switch of the first sample to be closed, test and obtain the first resistance data of the first sample, and feed it back to the processing and control module. After a specified interval, control the test switch of the first sample to be opened, and the test switch of the second sample to be closed, test and obtain the first resistance data of the second sample, and feed it back to the processing and control module. By analogy, test and obtain the first resistance data of all samples, and feed it back to the processing and control module. Step S3: Control the test switch of the first sample to close, test again to obtain the current resistance data of the first sample, and feed it back to the processing and control module, the processing and control module compares the current resistance data of the first sample with the first resistance data to determine whether the first sample has failed: when the current resistance data of the first sample increases by more than a set threshold value compared with the first resistance data, it is determined that the first sample has failed, the processing and control module controls the test switch of the first sample to open, and controls the short-circuit switch of the first sample to close, so that the first sample is short-circuited and exits the electromigration test; when the current resistance data of the first sample does not increase by more than a set threshold value compared with the first resistance data, it is determined that the first sample has not failed; after a specified interval time, and so on, the current resistance data of all samples are obtained in turn, and fed back to the processing and control module for failure determination; Step S4: Repeat step S3 until the processing and control module determines that all test samples have failed, disconnects the first main switch and the second main switch, and ends the electromigration test.

5. The method according to claim 4, characterized in that The prescribed interval time is 10s or 20s, and the set threshold is 10% or 20%.

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