Monitoring method, monitoring system and readable storage medium for cp test

Abstract

The application provides a CP test monitoring method, a monitoring system and a readable storage medium. The CP test monitoring method comprises the following steps: dividing a wafer into multiple areas according to a CP test sequence; obtaining a mean value and / or a standard deviation of a key parameter of a qualified die in each area; comparing a mean value deviation and / or a standard deviation deviation of the key parameter of the qualified die between the areas with a bottom line value; and determining that the CP test is abnormal if the mean value deviation and / or the standard deviation deviation is greater than the bottom line value. Thus, the CP test can be monitored after the CP test of each wafer, and timely monitoring of the CP test can be realized.

Description

Technical Field

[0001] This invention relates to the field of semiconductor technology, and in particular to a monitoring method, monitoring system, and readable storage medium for CP testing. Background Technology

[0002] In semiconductor manufacturing technology, chip production is extremely complex. The entire wafer fabrication process involves dozens or even more steps, such as photolithography, etching, material deposition, and ion implantation. Each step may introduce manufacturing defects or cause fluctuations in process characteristic parameters such as resistance and capacitance. Therefore, after manufacturing is completed, there may be some non-compliant dies on the wafer. These dies need to be screened through CP (Chip Probe) testing. The proportion of qualified products to the total number is the chip yield.

[0003] Specifically, wafer compositing (CP) testing is performed on wafers using a tester. During the testing process, occasional anomalies may occur, such as poor contact or damage to the tester. These often go unnoticed when chip yield is acceptable, but this significantly reduces the reliability of CP testing. Current technologies detect these anomalies through tester diagnostic files, daily standard wafer monitoring (Golden wafer monitor), or offline parameter monitoring by a YMS (Yield Management System). However, these monitoring methods are not timely enough; often, by the time an anomaly is detected, many batches of wafers have already been affected in the CP testing process.

[0004] Therefore, how to monitor CP testing in a timely manner has become a problem that needs to be solved by those skilled in the art. Summary of the Invention

[0005] The purpose of this invention is to provide a monitoring method, monitoring system, and readable storage medium for CP testing, so as to solve the problem that CP testing cannot be monitored in a timely manner in the prior art.

[0006] To address the aforementioned technical problems, this invention provides a monitoring method for CP testing, the monitoring method for CP testing comprising:

[0007] The wafer is divided into multiple zones according to the order of CP testing;

[0008] Obtain the mean and / or standard deviation of the key parameters for qualified grains in each region; and,

[0009] The mean deviation and / or standard deviation of the key parameters of qualified grains in each interval are compared with the baseline value. If the mean deviation and / or standard deviation is greater than the baseline value, the CP test is determined to be abnormal.

[0010] Optionally, in the CP test monitoring method, after determining that the CP test is abnormal, the CP test monitoring method further includes: issuing an alarm message.

[0011] Optionally, in the monitoring method for CP testing, the step of dividing the wafer into multiple regions according to the order of CP testing includes: dividing the qualified dies on the wafer into multiple regions according to the order of CP testing.

[0012] Optionally, in the monitoring method for CP testing, the step of dividing the wafer into multiple regions according to the order of CP testing includes: dividing the qualified dies on the wafer into multiple regions on an average basis according to the order of CP testing.

[0013] Optionally, in the monitoring method for the CP test, the step of obtaining the mean and / or standard deviation of the key parameters of qualified grains in each region includes:

[0014] From the CP test data of the said wafer, obtain the key parameters of each qualified grain in each region; and,

[0015] The mean of the key parameters of all qualified grains in each region is calculated using the mean method, and / or the standard deviation of the key parameters of all qualified grains in each region is calculated using the standard deviation method.

[0016] Optionally, in the monitoring method for the CP test, the step of obtaining the mean and / or standard deviation of the key parameters of qualified grains in each region includes: obtaining the mean and / or standard deviation of one or more key parameters of qualified grains in each region.

[0017] Optionally, in the monitoring method for the CP test, the key parameters include voltage, current, or resistance.

[0018] Optionally, in the monitoring method for the CP test, the baseline value includes a first baseline value and a second baseline value, wherein the first baseline value is used to compare with the mean deviation, and the first baseline value is a precision-related value of the testing machine; the second baseline value is used to compare with the standard deviation, and the second baseline value is a standard deviation-related value of an empirical value or a key parameter of a reference piece.

[0019] The present invention also provides a monitoring system for CP testing, the monitoring system for CP testing includes a processor and a memory, the memory stores a program, and when the program is executed by the processor, it implements the monitoring method for CP testing as described above.

[0020] The present invention also provides a readable storage medium having a program stored thereon, which, when executed, implements the monitoring method for CP testing as described above.

[0021] In the CP test monitoring method, monitoring system, and readable storage medium provided by the present invention, the wafer is divided into multiple regions according to the order of CP testing, the mean and / or standard deviation of the key parameters of qualified dies in each region are obtained, and the mean deviation and / or standard deviation of the key parameters of qualified dies in each region are compared with the baseline value. If the mean deviation and / or the standard deviation is greater than the baseline value, the CP test is determined to be abnormal. Thus, the CP test can be monitored immediately after the CP test of each wafer, thereby enabling timely monitoring of the CP test. Attached Figure Description

[0022] Figure 1 This is a flowchart illustrating the monitoring method for CP testing according to an embodiment of the present invention.

[0023] Figure 2 This is another flowchart illustrating the monitoring method for CP testing according to an embodiment of the present invention.

[0024] Figure 3 This is another flowchart illustrating the monitoring method for CP testing according to an embodiment of the present invention.

[0025] Figure 4 This is a schematic diagram of a wafer in the CP test monitoring method of this embodiment of the invention.

[0026] Figure 5 This is a schematic diagram of another wafer in the CP test monitoring method of this embodiment of the invention.

[0027] Figure 6 This is a schematic diagram of the mean value of a key parameter in the CP test monitoring method of this invention.

[0028] Figure 7 This is a schematic diagram of the standard deviation of a key parameter in the monitoring method of CP testing according to an embodiment of the present invention.

[0029] Figure 8 This is a block diagram of the monitoring system for CP testing according to an embodiment of the present invention.

[0030] The reference numerals in the attached figures are explained as follows:

[0031] 100 - Wafer; 101 - Region 1; 102 - Region 2; 103 - Region 3; 104 - Region 4; 105 - Region 5; 106 - Partition line; 110 - Grain; 111 - Acceptable grain; 112 - Unacceptable grain.

[0032] 200 - Processor; 210 - Memory. Detailed Implementation

[0033] The monitoring method, monitoring system, and readable storage medium for CP testing proposed in this invention will be further described in detail below with reference to the accompanying drawings and specific embodiments. The advantages and features of this invention will become clearer from the following description and claims. It should be noted that the drawings are all in a very simplified form and use non-precise proportions, and are only used to facilitate and clarify the illustration of the embodiments of this invention.

[0034] The terminology used in this invention is for the purpose of describing particular embodiments only and is not intended to limit the invention. Unless otherwise defined in this application, the technical or scientific terms used in this invention should be understood in their ordinary sense by one of ordinary skill in the art to which this invention pertains. The terms "first," "second," and similar terms used in this specification and claims do not indicate any order, quantity, or importance, but are merely used to distinguish different components. Similarly, "a" or "one," and similar terms do not indicate a quantity limitation, but rather indicate the presence of at least one. "A plurality" or "several" indicates two or more. Unless otherwise stated, terms such as "front," "rear," "lower," and / or "upper" are for ease of description only and are not limited to a location or spatial orientation. Terms such as "comprising" or "including" indicate that the element or object preceding "comprising" encompasses the element or object listed following "comprising" or its equivalents, and do not exclude other elements or objects. Terms such as "connected" or "linked" are not limited to physical or mechanical connections and can include electrical connections, whether direct or indirect. The singular forms “a,” “the,” and “the” used in this specification and appended claims are also intended to include the plural forms unless the context clearly indicates otherwise. It should also be understood that the term “and / or” as used herein refers to and includes any or all possible combinations of one or more of the associated listed items.

[0035] The core idea of ​​this invention is to provide a monitoring method, monitoring system, and readable storage medium for CP testing. This involves dividing a wafer into multiple regions according to the order of CP testing, obtaining the mean and / or standard deviation of key parameters for qualified dies in each region, and comparing the mean deviation and / or standard deviation of the key parameters for qualified dies in each region with a baseline value. If the mean deviation and / or the standard deviation is greater than the baseline value, the CP test is determined to be abnormal. This allows for monitoring of CP testing immediately after each wafer undergoes CP testing, thus enabling timely monitoring of the CP test.

[0036] For details, please refer to Figure 1 This is a flowchart illustrating a monitoring method for CP testing according to an embodiment of the present invention. Figure 1 As shown, in one embodiment of this application, the monitoring method for the CP test includes:

[0037] Step S10: Divide the wafer into multiple regions according to the order of CP testing;

[0038] Step S11: Obtain the average value of the key parameters of qualified grains in each region; and,

[0039] Step S12: Compare the mean deviation of the key parameters of qualified grains in each interval with the first baseline value. If the mean deviation is greater than the first baseline value, the CP test is determined to be abnormal.

[0040] Alternatively, please refer to Figure 2 This is another flowchart illustrating the monitoring method for CP testing according to an embodiment of the present invention. Figure 2 As shown, in another embodiment of this application, the monitoring method for the CP test includes:

[0041] Step S20: Divide the wafer into multiple regions according to the order of CP testing;

[0042] Step S21: Obtain the standard deviation of the key parameters of qualified grains in each region; and,

[0043] Step S22: Compare the standard deviation of the key parameters of qualified grains in each interval with the second baseline value. If the standard deviation is greater than the second baseline value, the CP test is determined to be abnormal.

[0044] Alternatively, please refer to Figure 3 This is another flowchart illustrating the monitoring method for CP testing according to an embodiment of the present invention. Figure 3 As shown, in another embodiment of this application, the monitoring method for the CP test includes:

[0045] Step S30: Divide the wafer into multiple regions according to the order of CP testing;

[0046] Step S31: Obtain the mean and standard deviation of the key parameters for qualified grains in each region; and,

[0047] Step S32: Compare the mean deviation of the key parameters of qualified grains in each interval with the first baseline value and compare the standard deviation of the key parameters of qualified grains in each interval with the second baseline value. If the mean deviation is greater than the first baseline value and the standard deviation is greater than the second baseline value, then the CP test is determined to be abnormal.

[0048] This involves acquiring one key parameter for each qualified die in each region, or multiple key parameters for each qualified die in each region, such as two, three, or more key parameters for each qualified die in each region. These key parameters can be directly obtained from the CP test data of the wafer. Furthermore, the key parameters include voltage, current, or resistance. For different types of qualified dies, the voltage, current, or resistance may specifically be, for example, turn-on voltage, breakdown voltage, cut-off current, leakage current, or on-resistance.

[0049] For further details, please refer to... Figure 4 This is a schematic diagram of a wafer in the CP testing monitoring method of an embodiment of the present invention. Figure 4 As shown, the wafer 100 is a wafer that has just completed CP testing. Multiple dies 110 are formed on the wafer 100, including qualified dies 111 and unqualified dies 112. In this embodiment, the CP test result of the wafer 100 is considered to be of acceptable yield.

[0050] Next, the wafer 100 is divided into multiple regions according to the CP test sequence. Please refer to [link / reference needed]. Figure 4 For example, in this embodiment, the CP test sequence of the wafer 100 is from left to right. Accordingly, the wafer 100 is divided into five regions from left to right: region 101, region 102, region 103, region 104, and region 105. In this embodiment, the partition lines 106 that divide the wafer 100 are straight lines. Specifically, the wafer 100 is divided into five regions from left to right using four partition lines 106.

[0051] In other embodiments of this application, the CP testing sequence of the wafer 100 can be further refined. For example, the CP testing sequence of the wafer 100 can be from left to right and from top to bottom. Furthermore, the partition line 106 that divides the wafer 100 can also be a broken line, such as... Figure 5As shown, the wafer 100 is divided into three regions according to its CP test sequence by two partition lines 106.

[0052] Preferably, the qualified dies 111 on the wafer 100 are divided into multiple regions according to the CP test order; that is, after removing unqualified dies 112, the wafer 100 is divided into regions according to the CP test order. Furthermore, preferably, the number of qualified dies 111 in each region is the same, that is, the qualified dies 111 on the wafer 100 are evenly divided into multiple regions according to the CP test order. For example... Figure 5 As shown, the wafer 100 is divided into three regions by two partition lines 106, and the number of qualified dies 111 in each region is the same.

[0053] Next, the mean and / or standard deviation of the key parameters of the qualified dies 111 in each region are obtained. Specifically, the key parameters of each qualified die 111 in each region can be obtained from the CP test data of the wafer 100, that is, the key parameters of all qualified dies 111 are obtained directly from the CP test data of the wafer 100. Here, taking the die 110 on the wafer 100 as a MOS device as an example, the key parameters can be, for example, leakage current (ICEs). That is, the leakage current (ICEs) values ​​of each qualified die 111 are obtained from the CP test data of the wafer 100. Next, the mean and / or standard deviation of the key parameters (ICEs) of all qualified dies 111 in each region are calculated. For example, to further improve the accuracy of the judgment, the mean and standard deviation of the key parameters of all qualified dies 111 in each region can be calculated simultaneously. The mean value of the key parameters of all qualified grains 111 in each region is obtained by the mean value calculation method, and the standard deviation of the key parameters of all qualified grains 111 in each region is obtained by the standard deviation calculation method. This application does not limit the specific calculation method.

[0054] Please refer to Figure 6 ,in, Figure 6 Correspondingly shown Figure 4 The ICEs values ​​for each qualified grain 111 in each of the five regions, and the average ICEs value for each region. For example... Figure 6 As shown, the ICEs values ​​of each qualified grain 111 in the first, second and third regions are very close, and their mean values ​​are also close, basically on the same line; the ICEs values ​​of each qualified grain 111 in the fourth and fifth regions are very different, and the mean values ​​obtained in these two regions are also very different from the mean values ​​obtained in the previous three regions.

[0055] In this embodiment, the standard deviation of key parameters for qualified grains 111 in each region was also obtained. Please refer to... Figure 7 Its corresponding illustration Figure 4 The standard deviation of ICEs for each qualified grain 111 in each of the five regions. For example... Figure 7 As shown, the standard deviations of the ICEs values ​​of qualified grains 111 in regions 1, 2, and 3 are very small and close to 0; while the standard deviations of the ICEs values ​​of qualified grains 111 in regions 4 and 5 are very large, around 30.

[0056] After obtaining the mean and standard deviation of the key parameters of the qualified dies 111 in each region, in this embodiment, the mean deviation of the key parameters of the qualified dies 111 in each region is then compared with a first baseline value, where the first baseline value is a precision-related value of the testing equipment. In this embodiment, the standard deviation of the key parameters of the qualified dies 111 in each region is also compared with a second baseline value, where the second baseline value is an empirical value or a standard deviation related value of the key parameters of a reference wafer. In this embodiment, if both comparison results are greater than, that is, if the mean deviation of the key parameters of the qualified dies 111 in each region is greater than the first baseline value and the standard deviation of the key parameters of the qualified dies 111 in each region is greater than the second baseline value, then the CP test is determined to be abnormal.

[0057] Preferably, the first baseline value is the accuracy value of the testing machine multiplied by a first coefficient, such as 1.01 to 1.15; the second baseline value is the standard deviation of a key parameter of a reference piece multiplied by a second coefficient, such as 1.01 to 1.15. The inventors have found that when the first and second baseline values ​​are taken at the above-mentioned values, the accuracy of CP test anomaly detection is extremely high, far exceeding the usual requirements for CP test anomaly detection accuracy.

[0058] In other embodiments of this application, only one of the following can be compared: The mean deviation of the key parameters of the qualified grains 111 in each interval is compared with a first baseline value; if the former is greater than the latter, the CP test is deemed abnormal. Alternatively, the standard deviation of the key parameters of the qualified grains 111 in each interval is compared with a second baseline value; if the former is greater than the latter, the CP test is deemed abnormal.

[0059] Specifically, for multiple zones, if the mean deviation and / or standard deviation of the key parameters of qualified dies 111 in two zones exceeds the minimum threshold, it is considered an abnormality in the CP test; if the mean deviation and / or standard deviation of the key parameters of qualified dies 111 in no two zones exceeds the minimum threshold, it is considered that there is no abnormality in the CP test. That is, taking a three-zone system as an example, if the mean deviation and / or standard deviation of the key parameters of qualified dies 111 in one group of two zones exceeds the minimum threshold, it is considered an abnormality in the CP test; if the mean deviation and / or standard deviation of the key parameters of qualified dies 111 in all three groups of two zones does not exceed the minimum threshold, it is considered that there is no abnormality in the CP test.

[0060] by Figure 4 Taking the division into five regions as an example, the mean deviation of the key parameters of qualified grain 111 between each pair of regions can be calculated, and then directly compared with the first baseline value. Thus, ten comparisons will be made. If any one exceeds the limit, the CP test is judged to be abnormal.

[0061] Alternatively, the mean deviation of the key parameters of the qualified grain 111 between each pair of regions can be calculated separately. Then, the maximum mean deviation is obtained and directly compared with the first baseline value. This will result in a direct comparison. If the comparison result is greater than the maximum, the CP test is considered abnormal; otherwise, the CP test is considered normal. In this case, the mean deviations other than the maximum mean deviation are equivalent to an indirect comparison with the first baseline value.

[0062] Similarly, with Figure 4 Taking the division into five regions as an example, the standard deviation of the key parameters of the qualified grain 111 between each pair of regions can be calculated, and then directly compared with the second baseline value. Thus, ten comparisons will be made. If any one of them exceeds the limit, the CP test is judged to be abnormal.

[0063] Alternatively, the standard deviation of the key parameters of the qualified grain 111 between each pair of regions can be calculated separately. Then, the maximum standard deviation is obtained and directly compared with the second baseline value. This will result in a direct comparison. If the comparison result is greater than the maximum standard deviation, the CP test is considered abnormal; otherwise, the CP test is considered normal. In this case, the standard deviations other than the maximum standard deviation are equivalent to an indirect comparison with the second baseline value.

[0064] In summary, in this embodiment of the application, monitoring of CP testing can be achieved after 100 CP tests on each wafer, thereby enabling timely monitoring of CP testing.

[0065] In this embodiment of the application, after determining that the CP test is abnormal, the monitoring method for the CP test may further include issuing an alarm message. For example, an alarm sound or a notification message may be issued, and further, the notification message may be in the form of a pop-up window or an email.

[0066] Furthermore, embodiments of this application also provide a monitoring system for CP testing; please refer to [link / reference]. Figure 8 The monitoring system for the CP test includes a processor 200 and a memory 210. The memory 210 stores a program, which, when executed by the processor 200, implements the monitoring method for the CP test as described above.

[0067] For example, processor 200 can be a central processing unit (CPU), a network processor (NP), etc.; it can also be a digital signal processor (DSP), an application-specific integrated circuit (ASIC), a field-programmable gate array (FPGA), or other programmable logic devices, discrete gate or transistor logic devices, or discrete hardware components. The central processing unit (CPU) can be based on x86 or ARM architectures, etc.

[0068] For example, memory 210 can be volatile memory and / or non-volatile memory. Volatile memory may include, for example, random access memory (RAM) and / or cache memory. Non-volatile memory may include, for example, read-only memory (ROM), hard disk, erasable programmable read-only memory (EPROM), portable compact disc read-only memory (CD-ROM), USB memory, flash memory, etc.

[0069] Accordingly, this application also provides a readable storage medium storing a program thereon, which, when executed, implements the CP test monitoring method described above. The readable storage medium may store one or more computer-readable instructions, and may also store various applications and various data. The readable storage medium may, for example, be operated by a processor to run the program stored thereon, thereby implementing the CP test monitoring method described above.

[0070] Furthermore, in other implementations of this application, different combinations can be made according to the claims and the above embodiments to form different specific implementations. These will not be listed here. Those skilled in the art can make more variations based on the disclosed content without creative effort.

[0071] The above description is merely a description of preferred embodiments of the present invention and is not intended to limit the scope of the present invention in any way. Any changes or modifications made by those skilled in the art based on the above disclosure shall fall within the protection scope of the claims.

Claims

1. A monitoring method for CP testing, characterized in that, The monitoring method for the CP test includes: The wafer is divided into multiple zones according to the order of CP testing; Obtain the mean and / or standard deviation of the key parameters for qualified grains in each region; and, The mean deviation and / or standard deviation of the key parameters of qualified grains in each interval are compared with the baseline value. If the mean deviation and / or standard deviation is greater than the baseline value, the CP test is determined to be abnormal.

2. The monitoring method for CP testing as described in claim 1, characterized in that, After determining that the CP test is abnormal, the monitoring method for the CP test also includes issuing an alarm message.

3. The monitoring method for CP testing as described in claim 1, characterized in that, The step of dividing the wafer into multiple regions according to the CP test order includes: dividing the qualified dies on the wafer into multiple regions according to the CP test order.

4. The monitoring method for CP testing as described in claim 1, characterized in that, The step of dividing the wafer into multiple regions according to the CP test order includes: dividing the qualified dies on the wafer into multiple regions on an average basis according to the CP test order.

5. The monitoring method for CP testing as described in claim 1, characterized in that, The steps for obtaining the mean and / or standard deviation of the key parameters of qualified grains in each region include: From the CP test data of the said wafer, obtain the key parameters of each qualified grain in each region; and, The mean of the key parameters of all qualified grains in each region is calculated using the mean method, and / or the standard deviation of the key parameters of all qualified grains in each region is calculated using the standard deviation method.

6. The monitoring method for CP testing as described in any one of claims 1 to 5, characterized in that, The step of obtaining the mean and / or standard deviation of the key parameters of qualified grains in each region includes: obtaining the mean and / or standard deviation of one or more key parameters of qualified grains in each region.

7. The monitoring method for CP testing as described in any one of claims 1 to 5, characterized in that, The key parameters include voltage, current, or resistance.

8. The monitoring method for CP testing as described in any one of claims 1 to 5, characterized in that, The baseline values ​​include a first baseline value and a second baseline value. The first baseline value is used to compare with the mean deviation and is a value related to the accuracy of the testing machine. The second baseline value is used to compare with the standard deviation and is a value related to the standard deviation of an empirical value or a key parameter of a reference piece.

9. A monitoring system for CP testing, characterized in that, The monitoring system for the CP test includes a processor and a memory. The memory stores a program, and when the program is executed by the processor, it implements the monitoring method for the CP test as described in any one of claims 1 to 8.

10. A readable storage medium having a program stored thereon, characterized in that, When the program is executed, it implements the monitoring method for CP testing as described in any one of claims 1 to 8.

Images