Silicon wafer testing method and silicon wafer testing system

Abstract

The invention provides a silicon wafer test method, which comprises the following steps: executing a standard sample test to obtain standard sample test data; the standard sample test is executed on a standard sample carrying table; under the condition that the standard sample test data indicates that the probe does not need to be replaced, executing a sample test to obtain the sample test data; the sample test is executed on the sample carrying table; wherein the size of the standard sample is smaller than that of the sample, and the size of the standard sample carrying table is smaller than that of the sample carrying table. The probe state is judged according to the standard sample test data, the sample test is continued when the probe state meets the requirement, and the accuracy of the sample test is improved by monitoring the probe state. The standard sample test can be completed in a small range, so that time and space are saved, and the test efficiency is improved.

Description

Technical Field

[0001] The present application relates to the technical field of silicon wafer surface detection, and in particular to a silicon wafer testing method and a silicon wafer testing system. Background Art

[0002] In the semiconductor industry, the test accuracy of silicon wafer surface roughness directly affects the yield and performance of subsequent chip manufacturing processes. Therefore, accurate roughness test methods are essential to ensure the quality of silicon wafers. Currently, atomic force microscopes (AFM) are often used to test silicon wafer surface roughness. It obtains high-precision roughness data by contacting the probe with the silicon wafer surface and scanning the surface morphology.

[0003] However, the accuracy of AFM testing is significantly affected by the state of the probe. As the test progresses, the probe will age, wear or become contaminated due to long-term use, which will affect the test results. Since changes in the probe state are usually not easy to detect directly, and its intrinsic vibration frequency curve in surface scanning does not change significantly, the aging of the probe may gradually accumulate during the test, ultimately leading to a decrease in measurement accuracy. In related technologies, there is a lack of a monitoring mechanism for the probe state, which makes it difficult to fully guarantee the accuracy of the test.

[0004] Based on this, the present application provides a silicon wafer testing method and a silicon wafer testing system to improve the relevant technology. Summary of the invention

[0005] The purpose of this application is to provide a silicon wafer testing method and a silicon wafer testing system to monitor the probe status and improve the accuracy of sample testing.

[0006] The purpose of this application is achieved by the following technical solutions:

[0007] In a first aspect, the present application provides a silicon wafer testing method, the method comprising: performing a standard test to obtain standard test data; the standard test is performed on a standard carrier; when the standard test data indicates that the probe does not need to be replaced, performing a sample test to obtain sample test data; the sample test is performed on a sample carrier; wherein the size of the standard is smaller than the size of the sample, and the size of the standard carrier is smaller than the size of the sample carrier.

[0008] In some embodiments, the process of using the standard test data to determine whether the probe needs to be replaced includes: when the standard test data is within the target numerical range, determining that the standard test data indicates that the probe does not need to be replaced; or, when the standard test data is not within the target numerical range, determining that the standard test data indicates that the probe needs to be replaced.

[0009] In some embodiments, the method further comprises: if the standard sample test data indicates that the probe needs to be replaced, repeating the steps of replacing the probe and performing the standard sample test until the latest standard sample test data indicates that the probe does not need to be replaced.

[0010] In some embodiments, the method further includes: if the sample test is not completed, determining whether it is necessary to perform the standard sample test again; if it is necessary to perform the standard sample test again, performing the standard sample test again.

[0011] In some embodiments, the method further comprises: continuing to perform the sample test when there is no need to perform the standard sample test again.

[0012] In some embodiments, the method further comprises: ending the test when the sample test is completed.

[0013] In some embodiments, the method further includes: setting corresponding test points and / or scanning parameters for standard test; and / or setting corresponding test points and / or scanning parameters for sample test.

[0014] In some embodiments, the scanning parameters include one or more of a test area, a scanning rate, and a scanning resolution.

[0015] In a second aspect, the present application provides a silicon wafer testing system, the system comprising: a standard sample carrier; a sample carrier; and a control module for executing any of the above methods.

[0016] In some embodiments, the height of the standard carrier matches that of the sample carrier.

[0017] The present application provides a silicon wafer testing method and a silicon wafer testing system, which judges the probe state by standard sample test data, and continues to perform sample testing when the probe state meets the requirements. First, the standard sample test data is obtained by performing the standard sample test on the standard sample carrier. These standard sample data reflect the accuracy of the current probe state. When the standard sample test data shows that the probe does not need to be replaced (for example, the probe state has not changed significantly and meets the requirements), it means that the probe state is good and the sample test can be performed. At this time, the sample test will start to be executed and performed on the sample carrier to obtain the test data of the sample. Among them, the standard sample size used is smaller than the sample size, and the size of the standard sample carrier is smaller than the size of the sample carrier, so the standard sample test can be performed in a smaller range, ensuring the flexibility of the standard sample test and the efficiency of the overall test process. During the entire test process, the result of the standard sample test is used as a verification mechanism to ensure that problems are found and adjusted in time when the probe state is poor, thereby ensuring the accuracy of the sample test. The present application can monitor the probe state and reduce the decrease in measurement accuracy caused by probe aging, wear or contamination through the combination of standard sample test and sample test. The sample test will only continue when the standard test indicates that the probe does not need to be replaced, thereby improving the accuracy and stability of the silicon wafer roughness test. Secondly, since the standard size is smaller than the sample size, and the standard carrier size is smaller than the sample carrier size, the standard test can be completed in a smaller range, saving time and space and improving test efficiency. In addition, the effective monitoring of the standard test data allows the replacement of the probe to be automated, reducing manual intervention and improving the level of automation and work efficiency. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] The present application is further described below in conjunction with the accompanying drawings and specific implementation methods.

[0019] Figure 1 It is a structural schematic diagram of a standard sample carrier and a sample carrier provided in an embodiment of the present application.

[0020] Figure 2a It is a cross-sectional schematic diagram (front view) of a standard sample carrier provided in an embodiment of the present application.

[0021] Figure 2b It is a structural schematic diagram (top view) of a standard sample carrier provided in an embodiment of the present application.

[0022] Figure 3 It is a schematic diagram of a flow chart of a standard sample test provided in an embodiment of the present application.

[0023] Figure 4 It is a schematic diagram of a sample test process provided in an embodiment of the present application.

[0024] In the figure: 100, standard sample carrier; 101, groove; 200, sample carrier. DETAILED DESCRIPTION

[0025] The following will be combined with the drawings in this application to clearly and completely describe the technical solutions in the implementation mode of this application. Obviously, the described implementation mode is only a part of the implementation mode of this application, not all the implementation modes. Based on the implementation mode in this application, all other implementation modes obtained by those skilled in the art without creative work are within the scope of protection of this application.

[0026] In the description of the embodiments of the present application, it should be understood that the terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Thus, features defined as "first" and "second" may explicitly or implicitly include one or more of the features. In the description of the embodiments of the present application, the meaning of "multiple" is two or more, unless otherwise clearly and specifically defined.

[0027] The accuracy of AFM (Atomic Force Microscope) testing is highly dependent on the state of the needle tip. As the distance traveled by the needle tip increases during the test, the needle tip wears and ages under the force, or foreign matter adheres to it, resulting in a decrease in test accuracy. It is necessary to detect the probe state and replace the failed probe in time to ensure the accuracy of the test. In the test of silicon wafer roughness, the intrinsic vibration frequency curve of the probe often does not change significantly, but due to the aging of the probe, the accuracy of the roughness measurement deteriorates and the measured value is significantly smaller.

[0028] In the test of silicon wafers, due to the extremely small surface roughness of the silicon wafers, the aging of the probes will cause large errors in the test results, which is specifically manifested as a decrease in test accuracy. For example, the value obtained from the test is smaller than the true value.

[0029] In the automated testing process for ultra-flat samples, there is a lack of means to detect the status of the probe, making it difficult to ensure the accuracy of the test.

[0030] See also Figure 1 , Figure 2a and Figure 2b , Figure 1 1 is a schematic diagram of the structure of a standard sample carrier 100 and a sample carrier 200 provided in an embodiment of the present application. Figure 2a is a cross-sectional schematic diagram (front view) of a standard sample carrier 100 provided in an embodiment of the present application, Figure 2b It is a structural schematic diagram (top view) of a standard sample carrier 100 provided in an embodiment of the present application.

[0031] An embodiment of the present application provides a silicon wafer testing method, the method comprising: performing a standard test to obtain standard test data; the standard test is performed on a standard carrier 100; when the standard test data indicates that the probe does not need to be replaced, performing a sample test to obtain sample test data; the sample test is performed on a sample carrier 200; wherein the size of the standard is smaller than the size of the sample, and the size of the standard carrier 100 is smaller than the size of the sample carrier 200.

[0032] The sample is a silicon wafer sample. The above embodiment can realize the probe state monitoring. In the relevant silicon wafer test system, a standard sample carrier 100 is added, such as Figure 1 As shown. As an example, the height of the standard sample carrier 100 can be the same as or similar to the height of the sample carrier 200, and the standard sample carrier 100 can hold a standard sample of a certain size. The center of the standard sample carrier 100 has, for example, a groove 101 for fixing the sample, and the size of the card slot (i.e., the groove 101) can match the size of the standard sample, and the height of the groove 101 can match the thickness of the standard sample.

[0033] See also Figure 3 and Figure 4 , Figure 3 is a schematic diagram of a standard sample test process provided in an embodiment of the present application, Figure 4 It is a schematic diagram of a sample test process provided in an embodiment of the present application.

[0034] like Figure 3 and Figure 4 As shown, before performing a standard test and / or a sample test, or during the test, or after the test, the relevant test parameters (e.g., test points, scanning parameters) can be set or adjusted. As an example, the test parameters can be set when creating a test strategy (e.g., a standard test strategy, a sample test strategy). In some embodiments, the method may also include: setting test points and / or scanning parameters corresponding to the standard test; and / or, setting test points and / or scanning parameters corresponding to the sample test. Wherein, the test point is the position of the test point.

[0035] In some embodiments, the scanning parameters may include one or more of a test area, a scanning rate, and a scanning resolution.

[0036] In the above embodiment, the standard sample test may be, for example, a standard sample roughness test, and the sample test may be, for example, a sample roughness test.

[0037] For example, first, a standard sample can be prepared. For example, the standard silicon wafer can be cut to obtain silicon wafer slices of a certain size (for example, 20 mm×20 mm) as a standard sample. Next, place the standard sample on the standard sample carrier 100. Then, establish a standard sample test recipe (i.e., strategy), determine the location of the standard sample test (i.e., test point position), scanning parameters, scan 10 times, and save the standard sample test recipe. After that, run the standard sample test recipe. After the standard sample test is completed, the standard sample test data is obtained. According to the test requirements, the lower limit of the probe state deterioration can be determined based on this data (i.e., standard sample test data). The standard sample test data can reflect the probe state, and the standard sample data continuously measured here can reflect the law of the probe state.

[0038] In some embodiments, the process of using the standard test data to determine whether the probe needs to be replaced may include: when the standard test data is within the target numerical range, determining that the standard test data indicates that the probe does not need to be replaced; or, when the standard test data is not within the target numerical range, determining that the standard test data indicates that the probe needs to be replaced.

[0039] In some embodiments, the target numerical value range corresponding to the standard sample test data may be 0.225 nm to 0.238 nm.

[0040] In some embodiments, the method may further include: if the standard test data indicates that the probe needs to be replaced, repeating the steps of replacing the probe and performing the standard test until the latest standard test data indicates that the probe does not need to be replaced.

[0041] In the above embodiment, the automation program of the standard sample test is performed, and the probe state detection is performed according to the following process after the standard sample is prepared. First, the standard sample is placed. Next, a standard sample test recipe is established, the position (i.e., test point position) and scanning parameters of the standard sample test are determined, and the standard sample test recipe is saved. Then, automatic operation is turned on to obtain the standard sample test data. If the test value (i.e., the standard sample test data) is not within the target value range (e.g., less than the minimum value of the target value range), the probe is automatically replaced and the step of turning on automatic operation is jumped to. If the standard sample test result is qualified (i.e., the standard sample test data is within the target value range), sample test is performed.

[0042] For example, in a specific application scenario, the following steps S101 to S105 are performed to execute the standard sample test process.

[0043] S101: Prepare a standard sample. Cut the standard sample silicon wafer to obtain a standard sample slice (ie, standard sample) with a size of 20×20 mm.

[0044] S102: placing the standard sample, aligning the standard sample with the groove 101 of the standard sample carrier 100. For example, using tweezers to pick up the standard sample and place it on the standard sample carrier 100, so that the standard sample and the groove 101 of the standard sample carrier 100 are completely in contact.

[0045] S103: Establish a standard sample test recipe, determine the test point: select a fixed point (for example, select the center point of the standard sample); set the scanning scheme: repeatedly scan the fixed points of the standard sample, 5 times per group, and repeat 20 groups. Set the scanning parameters: set the test area to 2.5×2.5μm, the scanning rate to 0.5Hz, and the scanning resolution pixel to 256×256.

[0046] S104: Run the standard sample test recipe, for example, start the automatic run, and test the fixed points (ie, test points) of the standard sample slice.

[0047] S105: After the standard sample test is completed, the standard sample test data is obtained. If the test value (i.e., the standard sample test data) is not within the target value range (e.g., less than the minimum value of the target value range), a new probe is replaced and the process goes to step S104; if the standard sample test result is qualified (i.e., the standard sample test data is within the target value range), the sample test can continue.

[0048] In the above embodiment, according to the test requirements, the lower limit of the probe state deterioration can be determined according to the standard test data. As an example, assuming that the target value range corresponding to the standard test data is 0.225nm to 0.238nm, if the standard test data is 0.230nm, it is determined that the standard test data indicates that the probe does not need to be replaced; if the standard test data is 0.224nm, it is determined that the standard test data indicates that the probe needs to be replaced.

[0049] In the above standard sample test process, standard sample test data (for example, monitoring data of standard sample roughness value) is obtained, as shown in Table 1. This data (i.e., standard sample test data) can reflect the state of the probe, and improve the accuracy of the test by accurately monitoring the probe state and replacing the probe in time. At the same time, the probe can be replaced automatically, which improves the test efficiency. In Table 1, the full range is the difference between the maximum value and the minimum value. The standard sample test specifications corresponding to Table 1 are shown in Table 2. In Table 2, the control limit is a criterion for judging whether there is an abnormal cause in the production process or procedure. UCLx is the maximum value of the target value range corresponding to the standard sample test data, and LCLx is the minimum value of the target value range corresponding to the standard sample test data.

[0050] Table 1

[0051]

[0052] Table 2

[0053]

[0054] like Figure 4 As shown, in some embodiments, the method may further include: if the sample test is not completed, determining whether it is necessary to perform the standard sample test again; if it is necessary to perform the standard sample test again, performing the standard sample test again.

[0055] In some embodiments, the method may further include: continuing to perform the sample test when there is no need to perform the standard sample test again.

[0056] In some embodiments, the method may further include: ending the test when the sample test is completed.

[0057] For example, in a specific application scenario, the following steps S201 to S207 are performed to execute the sample testing process.

[0058] Step S201: Create a sample test recipe (i.e., strategy), set test points (a total of 25 points), scan parameters, and save the recipe. In the scanning parameters, set the test area to 2.5×2.5 μm, the scanning rate to 0.5 Hz, and the scanning resolution (pixel) to 256×256.

[0059] Step S202: Execute the standard sample test recipe.

[0060] Step S203: placing a sample or replacing a sample.

[0061] Step S204: Perform sample testing.

[0062] Step S205: Determine whether the sample test is completed (ie, whether all samples have been tested). If the sample test is completed, jump to step S207; if the sample test is not completed, execute step S206.

[0063] Step S206: Determine whether it is necessary to perform standard sample detection (ie, standard sample test) again; if not, repeat steps S203 to S204; if standard sample test is required, repeat steps S202 to S204.

[0064] Step S207: End the test.

[0065] Table 3

[0066]

[0067] From the test results in Table 3, it can be seen that after measuring slot 5, slot 12, and slot 23, because the standard sample test data exceeds the lower limit of the specification (i.e., less than the minimum value of the target value range), the system automatically replaces the probe and completes the test. In this way, the test efficiency is significantly improved, the standard deviation of the test samples is less than 1%, and the test stability and accuracy are improved. Among them, slot refers to the carrying position of the silicon wafer in the carrier.

[0068] In the sample test of silicon wafers, due to the extremely small surface roughness of the silicon wafers, the aging of the probe will cause a large error in the test results, which is specifically manifested as a deterioration in test accuracy, and the value obtained by the test is less than the true value. The above embodiment adds a specially designed standard sample carrier 100, combined with the written automatic test program (i.e., the automated program for standard sample testing), to achieve rapid and automatic monitoring of the probe state, thereby ensuring the accuracy of the sample test. Specifically, by adding the standard sample carrier 100 (hardware) and the automatic program (software), rapid testing of the standard sample is achieved, the accuracy of the standard sample test is improved, and the efficiency of the sample test is improved. By monitoring and recording the roughness data of the standard sample, the monitoring of the probe state is achieved, and combined with the automatic replacement of the probe, the accuracy of the test is guaranteed, the accuracy of the test is improved, and the test efficiency is improved.

[0069] The embodiment of the present application further provides a silicon wafer testing system, the system comprising a standard sample carrier 100, a sample carrier 200 and a control module, and the control module is used to execute any one of the above methods.

[0070] In some embodiments, the height of the standard sample carrier 100 can match that of the sample carrier 200. As an example, the height of the standard sample carrier 100 is the same as that of the sample carrier 200. As another example, the absolute value of the difference between the heights of the standard sample carrier 100 and the sample carrier 200 is less than the target difference. As yet another example, the ratio of the absolute value of the difference between the heights of the standard sample carrier 100 and the sample carrier 200 to the height of the sample carrier 200 is less than the target ratio. Among them, the target difference and the target ratio can be selected or pre-set according to the needs in the actual application, and the above embodiment does not limit this.

[0071] It should be noted that each embodiment in the present application is described in a progressive manner, and the same or similar parts between the embodiments can be referred to each other, and each embodiment focuses on the differences from other embodiments. In particular, for the product embodiment, since it is basically similar to the method embodiment, the description is relatively simple, and the relevant parts can be referred to the partial description of the method embodiment.

[0072] Unless otherwise defined, the technical terms or scientific terms used in the present disclosure should be understood by people with ordinary skills in the field to which the present disclosure belongs. The "first", "second" and similar words used in the present disclosure do not indicate any order, quantity or importance, but are only used to distinguish different components. "Include" or "comprise" and similar words mean that the elements or objects appearing before the word cover the elements or objects listed after the word and their equivalents, without excluding other elements or objects. "Connect" or "connected" and similar words are not limited to physical or mechanical connections, but can include electrical connections, whether direct or indirect. "Up", "down", "left", "right" and the like are only used to indicate relative positional relationships. When the absolute position of the described object changes, the relative positional relationship may also change accordingly.

[0073] It will be understood that when an element such as a layer, film, region, or substrate is referred to as being “on” or “under” another element, it can be “directly on” or “under” the other element or intervening elements may be present.

[0074] In the description of the above embodiments, specific features, structures, materials or characteristics may be combined in a suitable manner in any one or more embodiments or examples.

[0075] The above is only a specific embodiment of the present disclosure, but the protection scope of the present disclosure is not limited thereto. Any person skilled in the art who is familiar with the technical field can easily think of changes or substitutions within the technical scope disclosed in the present disclosure, which should be included in the protection scope of the present disclosure. Therefore, the protection scope of the present disclosure should be based on the protection scope of the claims.

Claims

1. A silicon wafer testing method, characterized in that: The method comprises: Performing a standard sample test to obtain standard sample test data; the standard sample test is performed on a standard sample carrier; When the standard sample test data indicates that the probe does not need to be replaced, performing a sample test to obtain sample test data; the sample test is performed on the sample carrier; The size of the standard sample is smaller than that of the sample, and the size of the standard sample carrier is smaller than that of the sample carrier.

2. The silicon wafer testing method according to claim 1, characterized in that: The process of using the standard sample test data to determine whether the probe needs to be replaced includes: In the case where the standard sample test data is within the target value range, determining that the standard sample test data indicates that the probe does not need to be replaced; or, In the case where the standard sample test data is not within the target value range, it is determined that the standard sample test data indicates that the probe needs to be replaced.

3. The silicon wafer testing method according to claim 1 or 2, characterized in that: The method further comprises: In the case where the standard sample test data indicates that the probe needs to be replaced, the steps of replacing the probe and performing the standard sample test are repeated until the latest obtained standard sample test data indicates that the probe does not need to be replaced.

4. The silicon wafer testing method according to claim 1, characterized in that: The method further comprises: In the case of incomplete sample testing, determine whether it is necessary to conduct standard sample testing again; If the standard test needs to be performed again, perform the standard test again.

5. The silicon wafer testing method according to claim 4, characterized in that: The method further comprises: If it is not necessary to perform the standard test again, continue with the sample test.

6. The silicon wafer testing method according to claim 4, characterized in that: The method further comprises: When the sample test is completed, the test is ended.

7. The silicon wafer testing method according to claim 1, characterized in that: The method further comprises: Set the test points and / or scanning parameters for the standard test; and / or, Set the test points and / or scanning parameters for the sample test.

8. The silicon wafer testing method according to claim 7, characterized in that: The scanning parameters include one or more of a test area, a scanning rate and a scanning resolution.

9. A silicon wafer testing system, characterized in that: The system comprises: Standard sample carrier; Sample stage; A control module, configured to execute the method according to any one of claims 1 to 8.

10. The silicon wafer testing system according to claim 9, characterized in that: The height of the standard sample carrier matches that of the sample carrier.

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