Wafer electrical property test method, storage medium and terminal

Abstract

The invention discloses a wafer electrical property test method, a storage medium and a terminal. The wafer electrical property test method comprises the following steps: acquiring a standard acupuncture image; obtaining a to-be-detected acupuncture image of the current test structure; judging whether the to-be-detected acupuncture image accords with expectation or not based on the standard acupuncture image; if so, completing the electrical test of the current test structure, and carrying out the electrical test of the next test structure; if not, increasing the insertion depth of the probe card of the current test structure once or multiple times; and after the needle insertion depth of the probe card is increased each time, re-acquiring a to-be-detected needle insertion image of the current test structure, and judging whether the re-acquired to-be-detected needle insertion image conforms to expectation or not. In the process of performing the electrical test on the current test structure, whether the needle insertion of the current test structure meets the expectation or not can be detected, so that the time of re-testing due to abnormal test data caused by the needle insertion problem after the test is completed is saved, and the efficiency of the electrical test of the wafer is effectively improved.

Description

Technical Field

[0001] The present invention relates to the field of semiconductor manufacturing technology, and in particular to a wafer electrical property testing method, a storage medium and a terminal. Background Art

[0002] Precise control and evaluation of wafer manufacturing runs through the entire wafer manufacturing process. To verify whether a wafer meets product specifications, in addition to measuring key dimensions and the thickness of deposited films at each step in the process, wafer electrical testing (Wafer Acceptance Test, WAT) is also required to detect whether the performance of key components meets the standards.

[0003] Wafer electrical testing tests the electrical parameters of specific test structures on the wafer, detects the process conditions of each wafer product, evaluates the quality and stability of the semiconductor manufacturing process, and determines whether the wafer product meets the electrical specification requirements of the process technology platform. The data from the wafer electrical testing can be used as a quality certificate for the delivery of wafer products. In addition, the data from the wafer electrical testing can also reflect the actual production conditions of the production line. By collecting and analyzing the data from the wafer electrical testing, the production line conditions can be monitored, the trend of production line changes can be determined, and warnings can be issued for possible situations.

[0004] With the advanced development of process technology, the number of products and devices that need to be verified are gradually increasing. In order to effectively meet the performance standards of devices, improving the efficiency of electrical testing has become a primary issue to be solved.

[0005] However, there are still many problems in the wafer electrical testing process in the prior art. Summary of the invention

[0006] The technical problem solved by the present invention is to provide a wafer electrical property testing method, a storage medium and a terminal to improve the efficiency of wafer electrical property testing.

[0007] To solve the above problems, the technical solution of the present invention provides a wafer electrical testing method, including: obtaining a standard needle puncture image; obtaining a needle puncture image to be detected of a current test structure; judging whether the needle puncture image to be detected meets expectations based on the standard needle puncture image; if it meets expectations, completing the electrical test of the current test structure and conducting an electrical test of the next test structure; if it does not meet expectations, increasing the probe card puncture depth of the current test structure once or multiple times; wherein, after each increase in the probe card puncture depth of the current test structure, the method also includes: re-acquiring the needle puncture image to be detected of the current test structure, and judging whether the re-acquired needle puncture image to be detected meets expectations based on the standard needle puncture image.

[0008] Optionally, the method for obtaining the standard acupuncture image includes: manually performing acupuncture on a test key; and obtaining a needle image of the manual acupuncture test key based on a scanning electron microscope, and using the image as the standard acupuncture image.

[0009] Optionally, the method for judging whether the acupuncture image to be detected meets expectations based on the standard acupuncture image includes: extracting standard acupuncture features of the standard acupuncture image; setting acupuncture feature threshold range based on the standard acupuncture features; extracting the acupuncture features to be detected of the acupuncture image to be detected; comparing the acupuncture features to be detected with the acupuncture feature threshold range to judge whether the acupuncture features to be detected are within the acupuncture feature threshold range.

[0010] Optionally, the method for setting the acupuncture feature threshold range based on the standard acupuncture feature includes: using a preset percentage range of the standard acupuncture feature as the acupuncture feature threshold range.

[0011] Optionally, the preset percentage range is: 80% to 100%.

[0012] Optionally, the standard acupuncture feature includes: the area of ​​the acupuncture region in the standard acupuncture image; the acupuncture feature to be detected includes: the area of ​​the acupuncture region in the acupuncture image to be detected.

[0013] Optionally, the standard acupuncture feature includes: the sum of the grayscale values ​​of all pixels in the acupuncture area in the standard acupuncture image; the acupuncture feature to be detected includes: the sum of the grayscale values ​​of all pixels in the acupuncture area in the acupuncture image to be detected.

[0014] Optionally, the range of increasing the probe piercing depth of the current test structure each time is 4 microns to 6 microns.

[0015] Optionally, when the number of times the probe card puncture depth of the current test structure is increased does not reach a preset number, and the re-acquired puncture image to be detected is judged to be consistent with expectations based on the standard puncture pattern, the electrical test of the current test structure is completed and the electrical test of the next test structure is carried out.

[0016] Optionally, when the number of processing times of increasing the probe card piercing depth of the current test structure reaches a preset number, and the re-acquired piercing image to be tested still does not meet expectations based on the standard piercing pattern, the wafer electrical test is terminated.

[0017] Correspondingly, the technical solution of the present invention also provides a storage medium on which computer instructions are stored, and when the computer instructions are executed, the steps of the method described in any one of the above technical solutions are executed.

[0018] Correspondingly, the technical solution of the present invention also provides a terminal, including a memory and a processor, wherein the memory stores computer instructions that can be executed on the processor, and when the processor executes the computer instructions, the steps of the method described in any one of the above technical solutions are executed.

[0019] Compared with the prior art, the technical solution of the present invention has the following advantages:

[0020] In the wafer electrical testing method of the technical solution of the present invention, during the electrical testing of the current test structure, it is determined whether the needle puncture image to be tested meets expectations based on the standard needle puncture image, so as to detect whether the needle puncture of the current test structure meets expectations. This avoids manually re-checking the needle puncture situation of each test structure with abnormal data after completing the electrical testing of all test structures, and saves the time for re-testing due to abnormal test data caused by needle puncture problems after the test is completed, thereby effectively improving the efficiency of wafer electrical testing.

[0021] Furthermore, when the number of times the probe card piercing depth of the current test structure is increased reaches a preset number, and the re-acquired piercing image to be tested based on the standard piercing pattern still does not meet expectations, the wafer electrical test is terminated. This avoids damage to the probe card or wafer caused by continuously increasing the probe card piercing depth, and plays a certain protective role on the probe card and wafer. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 Schematic diagram of logic operation of a wafer electrical property testing method according to an embodiment of the present invention;

[0023] Figure 2 Schematic diagram of the structure of a wafer to be tested in a wafer electrical property testing method according to an embodiment of the present invention;

[0024] Figure 3 It is a schematic diagram of the electrical connection structure of the probe card, the test key and the test structure of the wafer electrical test method according to the embodiment of the present invention;

[0025] Figure 4 Schematic diagram of a standard needle-piercing image of a wafer electrical property testing method according to an embodiment of the present invention;

[0026] Figure 5 Schematic diagram of a needle image to be detected in a wafer electrical property testing method according to an embodiment of the present invention;

[0027] Figure 6 2 is a schematic diagram of a structure of extracting standard needle piercing features from a standard needle piercing image of a wafer electrical property testing method according to an embodiment of the present invention;

[0028] Figure 7It is a structural schematic diagram of extracting features of the needles to be detected from the needle image to be detected in the wafer electrical property testing method according to an embodiment of the present invention. DETAILED DESCRIPTION

[0029] As described in the background art, there are still many problems in the wafer electrical property testing process in the prior art, which will be described in detail below.

[0030] During the wafer electrical test, the probe card needs to be inserted into the test pad, and the test structure (TestKey, TSK) is electrically connected to the test pad. If there are problems with the process (such as the uneven surface of the wafer), the probe card and the test key will not be in good contact. At this time, the electrical signal applied to the probe card is not the actual value, which affects the test results.

[0031] Currently, wafer electrical tests are all performed automatically through needle piercing tests. During the test, data anomalies caused by needle piercing problems cannot be directly discovered. If a problem occurs that causes test data anomalies, it is necessary to wait until all test structures have completed the test and then manually re-check the needle piercing conditions of each test structure with data anomalies and re-test. This process will extend the product testing time and waste some unnecessary waiting time. In addition, for some products with more test structures, the waiting time is even longer.

[0032] On this basis, the present invention provides a wafer electrical testing method, storage medium and terminal. In the process of electrical testing the current test structure, it is judged based on the standard needle-piercing image whether the needle-piercing image to be tested meets expectations, so as to detect whether the needle-piercing of the current test structure meets expectations. This avoids manually re-checking the needle-piercing situation of each test structure with data abnormalities after completing the electrical testing of all test structures, saves unnecessary waiting time, and can effectively improve the efficiency of wafer electrical testing.

[0033] In order to make the above-mentioned objects, features and advantages of the present invention more obvious and easy to understand, specific embodiments of the present invention are described in detail below with reference to the accompanying drawings.

[0034] Figure 1 Schematic diagram of logic operation of a wafer electrical property testing method according to an embodiment of the present invention; Figure 2 Schematic diagram of the structure of a wafer to be tested in a wafer electrical property testing method according to an embodiment of the present invention; Figure 3 It is a schematic diagram of the electrical connection structure of the probe card, the test key and the test structure of the wafer electrical test method according to the embodiment of the present invention; Figure 4 Schematic diagram of a standard needle-piercing image of a wafer electrical property testing method according to an embodiment of the present invention; Figure 5 Schematic diagram of a needle image to be detected in a wafer electrical property testing method according to an embodiment of the present invention; Figure 62 is a schematic diagram of a structure of extracting standard needle piercing features from a standard needle piercing image of a wafer electrical property testing method according to an embodiment of the present invention; Figure 7 It is a structural schematic diagram of extracting features of the needles to be detected from the needle image to be detected in the wafer electrical property testing method according to an embodiment of the present invention.

[0035] Please refer to Figures 1 to 3 , the wafer 100 to be inspected is transferred to the testing machine.

[0036] It should be noted that a plurality of test structures 101 are provided in the wafer 100 to be tested, and each test structure 101 is electrically connected to a corresponding test key 102. During the process of conducting the electrical test of the wafer, the probe card 103 in the test machine is inserted into the corresponding test key 102 to complete the electrical test of the test structure 101. The electrical test of the test structure 101 is performed to reflect the actual production situation of the production line. Since the test structure 101 is only used for electrical testing and is not used as a device structure with actual functions in the chip, the test structure 101 is set in the cutting path area of ​​the wafer 100 to avoid occupying the area of ​​the chip area. After the electrical test of the wafer is completed, the wafer 100 to be tested will be cut into a plurality of chips along the cutting path area, and the test structure 101 set in the cutting path area of ​​the wafer 100 to be tested will also be damaged.

[0037] Please refer to Figure 4 And continue to combine reference Figure 1 , obtain the standard acupuncture image 200.

[0038] In this embodiment, the method for obtaining the standard acupuncture image 200 includes: manually performing acupuncture on the test key 102 ; and obtaining an acupuncture image of the manual acupuncture test key 102 based on a scanning electron microscope and using the image as the standard acupuncture image 200 .

[0039] It should be noted that, in this embodiment, after obtaining the needle puncture image of the manual needle puncture test key 102, it is judged based on human experience whether the needle puncture situation reflected by the needle puncture image meets expectations. If the human judgment meets expectations, it is used as the standard needle puncture image 200; if the human judgment does not meet expectations, manual needle puncture is performed again until a needle puncture image that meets the expected needle puncture situation is obtained. After the preliminary judgment based on human experience that the needle puncture image meets expectations, it is also necessary to detect whether the test data of the current needle puncture corresponding test structure is correct. If the test data is correct, the corresponding needle puncture image is used as the standard needle puncture image 200. . In the subsequent wafer electrical test process, the needle puncture situation reflected by the standard needle puncture image 200 will be regarded as the needle puncture situation that meets expectations, and the standard needle puncture image 200 will be used as a reference to judge the automatic needle puncture situation in the test machine.

[0040] Since the standard of human experience judgment is subjective, if the human judgment shows that the acupuncture image meets expectations, but the test data of the actual test structure is problematic, it is difficult to determine whether the abnormal test data is caused by the acupuncture problem or the test structure itself. If the human judgment shows that the acupuncture image meets expectations, and the test data of the test structure is also correct, the problem of the acupuncture image being non-standard can be ruled out.

[0041] In this embodiment, the scanning electron microscope is an image capturing function provided by the testing machine.

[0042] Please refer to Figure 5 And continue to combine reference Figure 1 , obtaining the acupuncture image 300 to be detected of the current test structure.

[0043] It should be noted that the needle pricking corresponding to the needle pricking image 300 to be detected is an automatic needle pricking performed by a testing machine, and the needle pricking image 300 to be detected is also obtained based on a scanning electron microscope of the testing machine.

[0044] Please continue to refer to Figure 1 , based on the standard acupuncture image 200, it is determined whether the acupuncture image to be detected 300 meets expectations.

[0045] In this embodiment, the method for judging whether the acupuncture image 300 to be detected meets expectations based on the standard acupuncture image 200 includes: extracting the standard acupuncture features of the standard acupuncture image 200; setting the acupuncture feature threshold range based on the standard acupuncture features; extracting the acupuncture features to be detected of the acupuncture image to be detected; comparing the acupuncture features to be detected with the acupuncture feature threshold range, and judging whether the acupuncture features to be detected are within the acupuncture feature threshold range.

[0046] In this embodiment, the method for setting the acupuncture feature threshold range based on the standard acupuncture feature includes: using a preset percentage range of the standard acupuncture feature as the acupuncture feature threshold range; the preset percentage range is: 80% to 100%.

[0047] In this embodiment, the standard acupuncture feature is the area of ​​the acupuncture region in the standard acupuncture image 200 ; the acupuncture feature to be detected is the area of ​​the acupuncture region in the acupuncture image 300 to be detected.

[0048] Please refer to Figure 6 In this embodiment, the method for obtaining the area of ​​the acupuncture region in the standard acupuncture image 200 includes: the test machine finds the acupuncture region in the standard acupuncture image 200 through the boundary box recognition of the test key 102; extracts the edge contour of the acupuncture region, and calculates the area of ​​the region surrounded by the edge contour.

[0049] Please refer to Figure 7 Similarly, the method for acquiring the area of ​​the acupuncture region in the acupuncture image 300 to be detected is also acquired by the same processing method.

[0050] In other embodiments, the standard acupuncture feature may also be the sum of the grayscale values ​​of all pixels in the acupuncture area in the standard acupuncture image; the corresponding acupuncture feature to be detected is the sum of the grayscale values ​​of all pixels in the acupuncture area in the acupuncture image to be detected.

[0051] In other embodiments, the method for obtaining the sum of the grayscale values ​​of all pixels in the acupuncture area in the standard acupuncture image includes: grayscale processing of the standard acupuncture image; the test machine finds the acupuncture area in the standard acupuncture image through test key boundary box recognition; obtains the grayscale values ​​of all pixels in the acupuncture area and sums them.

[0052] Similarly, the method for acquiring the area of ​​the acupuncture region in the acupuncture image to be detected is also acquired by adopting the same processing method.

[0053] Please continue to refer to Figure 1 If it meets expectations, the electrical test of the current test structure is completed and the electrical test of the next test structure is performed.

[0054] It should be noted that, since the probe card 103 is inserted after the test key 102, the test machine inputs the corresponding electrical test signal to the test structure 101, that is, the probe card 103 also completes the electrical test operation on the test structure 101 after the test key 102 is inserted, so when it is judged that the insertion of the current test structure meets expectations, the electrical test of the current test structure is also completed. When performing the electrical test of the next test structure, the next test structure is regarded as the current test structure, and then the corresponding operation of the current test structure described above is completed, and this cycle is repeated until the electrical test of all test structures 101 on the wafer 100 to be tested is completed.

[0055] In this embodiment, when the acupuncture feature to be detected is within the acupuncture feature threshold range, it is determined that the acupuncture image 300 to be detected meets expectations.

[0056] Please continue to refer to Figure 1 If it does not meet expectations, the insertion depth of the probe card 103 of the current test structure is increased once or multiple times.

[0057] In this embodiment, when the acupuncture feature to be detected is not within the acupuncture feature threshold range, it is determined that the acupuncture image 300 to be detected does not meet expectations.

[0058] In this embodiment, the range of the needle insertion depth of the probe card 103 of the current test structure each time is increased is 4 microns to 6 microns; preferably, the needle insertion depth of the probe card 103 of the current test structure each time is increased is 5 microns.

[0059] Please continue to refer to Figure 1 , after each increase in the needle insertion depth of the probe card 103 of the current test structure, it also includes: reacquiring the needle insertion image 300 to be detected of the current test structure, and judging whether the reacquired needle insertion image 300 to be detected meets expectations based on the standard needle insertion image 200.

[0060] In the process of electrical testing the current test structure, whether the needle puncture image 300 to be tested meets expectations is judged based on the standard needle puncture image 200, so as to detect whether the needle puncture of the current test structure meets expectations. This avoids manually re-checking the needle puncture situation of each test structure 101 with data abnormalities after completing the electrical testing of all test structures 101, thereby saving unnecessary waiting time and effectively improving the efficiency of wafer electrical testing.

[0061] Please continue to refer to Figure 1 In this embodiment, the process of judging whether the re-acquired acupuncture image 300 to be detected meets the expectations based on the standard acupuncture image 200 is the same as the above process, and will not be described in detail here.

[0062] Please continue to refer to Figure 1 In the present embodiment, when the number of times the puncture depth of the probe card 103 of the current test structure is increased does not reach the preset number, and the re-acquired puncture image 300 to be detected is judged to be in line with expectations based on the standard puncture pattern, the electrical test of the current test structure is completed, and the electrical test of the next test structure is performed.

[0063] Please continue to refer to Figure 1In this embodiment, when the number of times the needle depth of the probe card 103 of the current test structure is increased reaches a preset number, and the needle image 300 to be detected that is re-acquired based on the standard needle pattern still does not meet expectations, the electrical test of the current test structure is terminated, the probe card 103 is replaced, and the electrical test of the current test structure is continued. Since the needle depth of the probe card 103 has a limit value, if it exceeds the limit value, it will cause damage to the probe card 103 or the wafer. Therefore, by setting a preset number of times, the probe card 103 is prevented from being subjected to an unlimited number of needle depth increase processes, thereby avoiding damage to the probe card 103 or the wafer caused by continuously increasing the needle depth of the probe card 103, and playing a certain protective role for the probe card 103 and the wafer.

[0064] For example, in a specific embodiment, if the needle depth of the probe card 103 of the current test structure is increased by 5 microns each time, and the maximum needle depth allowed by the probe card 103 is 18 microns, the corresponding preset number of times should be set to 3. When the needle depth of the probe card 103 is increased 3 times, the corresponding needle depth of the probe card 103 is 3*5 microns=15 microns. If the needle depth of the probe card 103 is increased again, the corresponding needle depth is 4*5 microns=20 microns, which will exceed the limit value of the needle depth of the probe card 103 and will not be allowed.

[0065] Please continue to refer to Figure 1 In the present embodiment, when the number of times the puncture depth of the probe card 103 of the current test structure is increased reaches a preset number, and the re-acquired puncture image 300 to be detected is judged to be in line with expectations based on the standard puncture pattern, the electrical test of the current test structure is completed, and the electrical test of the next test structure is performed.

[0066] Correspondingly, the technical solution of the present invention also provides a storage medium on which computer instructions are stored, and when the computer instructions are executed, the steps of the method described in any one of the above embodiments are executed.

[0067] Correspondingly, the technical solution of the present invention also provides a terminal, including a memory and a processor, wherein the memory stores computer instructions that can be executed on the processor, and when the processor executes the computer instructions, the steps of the method described in any one of the above embodiments are executed.

[0068] Although the present invention is disclosed as above, the present invention is not limited thereto. Any person skilled in the art can make various changes and modifications without departing from the spirit and scope of the present invention. Therefore, the protection scope of the present invention shall be subject to the scope defined by the claims.

Claims

1. A wafer electrical property testing method, characterized in that: include: Acquire standard acupuncture images; Obtain the needle-piercing image to be detected of the current test structure; Determining whether the acupuncture image to be detected meets expectations based on the standard acupuncture image; If it meets expectations, the electrical test of the current test structure is completed, and the electrical test of the next test structure is performed; If it does not meet expectations, increasing the probe card piercing depth of the current test structure once or multiple times; Wherein, after increasing the probe card insertion depth of the current test structure each time, the method further includes: The acupuncture image to be detected of the current test structure is reacquired, and it is determined whether the acupuncture image to be detected reacquired meets expectations based on the standard acupuncture image.

2. The wafer electrical property testing method according to claim 1, wherein: The method for obtaining the standard acupuncture image includes: manually acupuncturing a test key; obtaining an acupuncture image of the manual acupuncture test key based on a scanning electron microscope and using the image as the standard acupuncture image.

3. The wafer electrical property testing method according to claim 1, wherein: The method for judging whether the acupuncture image to be detected meets expectations based on the standard acupuncture image includes: extracting the standard acupuncture features of the standard acupuncture image; setting a threshold range of acupuncture features based on the standard acupuncture features; extracting the acupuncture features to be detected of the acupuncture image to be detected; comparing the acupuncture features to be detected with the acupuncture feature threshold range, and judging whether the acupuncture features to be detected are within the acupuncture feature threshold range.

4. The wafer electrical property testing method according to claim 3, characterized in that: The method for setting the threshold range of acupuncture feature based on the standard acupuncture feature includes: using a preset percentage range of the standard acupuncture feature as the threshold range of acupuncture feature.

5. The wafer electrical property testing method according to claim 4, characterized in that: The preset percentage range is: 80% to 100%.

6. The wafer electrical property testing method according to claim 3, characterized in that: The standard acupuncture feature includes: the area of ​​the acupuncture region in the standard acupuncture image; the acupuncture feature to be detected includes: the area of ​​the acupuncture region in the acupuncture image to be detected.

7. The wafer electrical property testing method according to claim 3, characterized in that: The standard acupuncture feature includes: the sum of the grayscale values ​​of all pixels in the acupuncture area in the standard acupuncture image; the acupuncture feature to be detected includes: the sum of the grayscale values ​​of all pixels in the acupuncture area in the acupuncture image to be detected.

8. The wafer electrical property testing method according to claim 1, wherein: The range of increasing the probe piercing depth of the current test structure each time is 4 microns to 6 microns.

9. The wafer electrical property testing method according to claim 1, wherein: When the number of times the probe card puncture depth of the current test structure is increased does not reach the preset number, and the re-acquired puncture image to be detected is judged to be consistent with expectations based on the standard puncture pattern, the electrical test of the current test structure is completed and the electrical test of the next test structure is carried out.

10. The wafer electrical property testing method according to claim 1, wherein: When the number of increasing processing times of the probe card piercing depth of the current test structure reaches a preset number, and the re-acquired piercing image to be tested still does not meet expectations based on the standard piercing pattern, the wafer electrical test is terminated.

11. A storage medium having computer instructions stored thereon, characterized in that: When the computer instructions are executed, the steps of the method according to any one of claims 1 to 10 are executed.

12. A terminal comprising a memory and a processor, wherein the memory stores computer instructions that can be executed on the processor, characterized in that: When the processor runs the computer instructions, the steps of the method according to any one of claims 1 to 10 are performed.

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