Method for monitoring degree of epitaxial filling of deep trench super junction mosfet product in real time

Abstract

The present invention provides a method for monitoring the degree of epitaxial filling of a deep trench super junction MOSFET product in real time. During epitaxial filling, real-time temperature data of a surface of a substrate is acquired by means of a temperature detector, so as to feed back regular temperature curve fluctuations obtained by different temperature reading values, and then a degree of epitaxial filling is determined on the basis of the temperature curve fluctuations, thereby achieving real-time and precise monitoring of the degree of epitaxial filling of a deep trench super junction MOSFET product.

Description

Methods for Real-Time Monitoring of Epitaxial Fill Degree in Deep Trench Superjunction MOSFET Products Technical Field

[0001] This invention relates to the field of semiconductor technology, and in particular to a method for real-time monitoring of the epitaxial fill degree of deep trench superjunction MOSFET products. Background Technology

[0002] Deep trench superjunction MOSFETs are widely used in cloud servers, UPS uninterruptible power management, LED lighting, smart bicycles, mobile terminals and other fields due to their ultra-low on-resistance, ultra-fast switching speed, low internal resistance, low power consumption, high efficiency and small chip size. The application range covers various products from 200 to 1000V and the product types are complex and diverse.

[0003] Deep trench epitaxial filling is a critical step in superjunction projects. In the alternating formation of P-type and N-type semiconductor thin layers, the P-type semiconductor thin layer is formed using a deep trench filling process. This involves first creating deep trenches on the N-type epitaxial layer, and then filling the deep trenches with P-type epitaxial material using a silicon filling process. Deep trench epitaxial filling is a crucial process in the manufacturing of these products. Its epitaxial filling performance and filling time are affected by factors such as the size of the deep trench, resulting in varying filling times for different customer designs. The degree of epitaxial filling affects the product's electrical parameters. Insufficient filling time leads to inadequate trench filling, resulting in gaps within the deep trench. Excessive filling time leads to overfilling, causing stress-related defects such as dislocations, which in turn result in leakage current and low yield. Furthermore, excessive filling time also impacts production capacity.

[0004] Because the epitaxial filling process of deep trench superjunction (SJNFET) products involves directly growing single-crystal silicon on the surface of single-crystal silicon within deep trenches, it is impossible to directly measure the film thickness to monitor the degree of epitaxial filling. Previous methods monitored the degree of epitaxial filling using optical microscopy images or CMP End Point Detection (EPD) technology. However, microscopic images can only provide a rough assessment, and while CMP EPD detection is more accurate, it has a delay and cannot provide timely feedback on the degree of epitaxial filling. Summary of the Invention

[0005] The purpose of this invention is to provide a method for monitoring the epitaxial fill degree of deep trench superjunction MOSFET products, so as to achieve real-time and accurate monitoring of the epitaxial fill degree of deep trench superjunction.

[0006] To achieve the above objectives, the present invention provides a method for monitoring the epitaxial fill degree of deep trench superjunction MOSFET products, comprising:

[0007] A substrate with a dielectric layer on its surface is placed in a cavity with a temperature sensor, and an epitaxial filling of a substrate with deep trenches is performed in the cavity. The epitaxial filling includes growing an epitaxial layer in the deep trenches of the substrate until the epitaxial layer flips over to cover part or all of the dielectric layer on the surface of the substrate.

[0008] During epitaxial filling, the temperature detector probes real-time temperature data of the substrate surface; and,

[0009] The degree of epitaxial filling is monitored in real time based on temperature data detected by a temperature detector.

[0010] Optionally, the dielectric layer includes a silicon nitride layer and / or a silicon oxide layer, and the epitaxial layer includes a single-crystal silicon layer.

[0011] Optionally, the temperature detector is an infrared detector.

[0012] Optionally, the temperature detector is connected to a temperature monitoring system.

[0013] Optionally, the method for monitoring the degree of epitaxial filling also includes: a data module establishment program, which includes: collecting temperature data corresponding to different time periods in the epitaxial filling process of the same product, forming a correspondence between filling process time periods and temperature, and establishing a data module.

[0014] Optionally, monitoring the substrate epitaxial fill level based on temperature data detected by a temperature detector includes: a data processing program, the data processing program including:

[0015] The correspondence between process time period and temperature in the data module is retrieved. Based on the real-time temperature data detected by the temperature detector, the real-time process time period corresponding to the real-time temperature is obtained, and the degree of epitaxial filling is determined.

[0016] Optionally, the method for monitoring the degree of epitaxial fill further includes: an automatic termination procedure for epitaxial fill, wherein the automatic termination procedure for epitaxial fill includes:

[0017] The process involves setting up automatic termination conditions for epitaxial processes. When the temperature data detected by the temperature detector meets the conditions, the automatic termination of epitaxial filling is triggered.

[0018] Optionally, the automatic termination procedure for epitaxial filling further includes: amplifying the collected temperature data.

[0019] Optionally, the signal amplification process includes:

[0020] S1: Collect temperature data V at intervals t, and process the collected temperature data V, including:

[0021] S11: Take 10 sets of temperature data sequentially and calculate the average value X: X i-1 =(V i-10 +V i-9 +V i-8 +V i-7 +V i-6 +V i-5 +V i-4 +V i-3 +V i-2 +V i-1 ) / 10, X i =(V i-9 +V i-8 +V i-7 +V i-6 +V i-5 +V i-4 +V i-3 +V i-2 +V i-1 +V i ) / 10,

[0022] Where i > 10;

[0023] S12: Calculate the difference Δ, Δ j =X i -X i-1 , where j = i - 10;

[0024] S13: Take n Δ values ​​in sequence and sum them up to S. Where k = j + n - 1, n ≥ 10;

[0025] S2: Judge S; when m consecutive (m≥5) S values ​​are all less than the set value T, start using X. i Determine the position of the wave crest and record the corresponding process time period.

[0026] Optional, use X i Determining the peak position includes: when Max(X) i-3 X i-2 X i-1 X i X i+1 X i+2 X i+3 ) = X i X i That is, the position of the wave crest.

[0027] Optionally, in the signal amplification process, t = 3s, n = 20, and m = 5.

[0028] In summary, this invention provides a method for monitoring the epitaxial fill degree of deep trench superjunction MOSFET products. During the epitaxial fill period, real-time temperature data of the substrate surface is acquired by a temperature detector, thereby feeding back regular temperature curve fluctuations obtained from different temperature readings. The epitaxial fill degree is then determined based on the temperature curve fluctuations, achieving real-time and accurate monitoring of the epitaxial fill degree of deep trench superjunction MOSFET products. Attached Figure Description

[0029] Figure 1 is a flowchart illustrating the method for monitoring the epitaxial fill degree of deep trench superjunction MOSFET products provided in an embodiment of the present invention;

[0030] Figure 2 is a schematic diagram of the structure after forming a deep trench in the method for monitoring the degree of epitaxial filling provided in an embodiment of the present invention.

[0031] Figure 3 is a schematic diagram of the structure after epitaxial filling in the method for monitoring the degree of epitaxial filling provided in an embodiment of the present invention.

[0032] Figure 4 is a schematic diagram of the cavity corresponding to the epitaxial filling process;

[0033] Figure 5 shows the temperature curves of the substrate surface detected by the temperature detector during epitaxial filling;

[0034] Figure 6 shows the temperature curve of the fluctuating temperature detected by the temperature detector in Figure 5.

[0035] Figures 7A to 7E are FA SEM images of the MOSFET products corresponding to different time periods of the temperature curves in Figure 6;

[0036] Figure 8 shows the temperature curves corresponding to different production time periods after temperature data processing provided in the embodiment of the present invention;

[0037] Figure 9 shows the temperature curves corresponding to the deep trench epitaxial filling etched by different etching machines using the same process.

[0038] The reference numerals in the attached figures are explained as follows: 100-substrate; 110-deep trench; 101-dielectric layer; 102-epitaxy layer. Detailed Implementation

[0039] To make the content of this invention clearer and easier to understand, the following description, in conjunction with the accompanying drawings, further illustrates the invention. Of course, this invention is not limited to this specific embodiment, and common substitutions well-known to those skilled in the art are also covered within the scope of protection of this invention.

[0040] Secondly, the present invention is described in detail using schematic diagrams. When describing the examples of the present invention in detail, for ease of explanation, the schematic diagrams are not enlarged to a certain extent according to the general proportions, and this should not be regarded as a limitation of the present invention.

[0041] For ease of description, some embodiments of the present invention may use spatially relative terms such as “above,” “below,” “top,” and “under” to describe the relationship between one element or component and another (or more) elements or components as shown in the accompanying drawings of the embodiments. It should be understood that, in addition to the orientations described in the drawings, the spatially relative terms are also intended to include different orientations of the device during use or operation. For example, if the device in the drawings is flipped, it is described as an element or component “below” or “under” other elements or components, and will subsequently be positioned “above” or “on” other elements or components. The terms “first,” “second,” etc., used below are used to distinguish between similar elements and are not necessarily used to describe a particular order or temporal sequence.

[0042] Figure 1 is a flowchart illustrating a method for monitoring the epitaxial fill degree of a deep trench superjunction MOSFET product according to an embodiment of the present invention. As shown in Figure 1, the method for monitoring the epitaxial fill degree of a deep trench superjunction MOSFET product provided in this embodiment includes the following steps:

[0043] Step S01: Place a substrate with a dielectric layer on its surface into a cavity with a temperature sensor, and perform epitaxial filling on the substrate with deep trenches in the cavity. The epitaxial filling includes growing an epitaxial layer in the deep trenches of the substrate until the epitaxial layer flips over to cover part or all of the dielectric layer on the surface of the substrate.

[0044] Step S02: During the epitaxial filling of the substrate, the temperature detector detects real-time temperature data of the substrate surface; and,

[0045] Step S03: Monitor the degree of epitaxial filling in real time based on the temperature data detected by the temperature detector.

[0046] The following describes in detail, with reference to Figures 1 to 6, a method for monitoring the epitaxial fill degree of deep trench superjunction MOSFET products.

[0047] Referring to Figure 4, a substrate 100 to be epitaxially filled is loaded into a cavity with a temperature sensor, and epitaxial filling is performed in the cavity. The epitaxial filling includes growing an epitaxial layer 102 in a deep trench 110 of the substrate 100 until the epitaxial layer 102 flips outward to cover a portion of the substrate surface 100.

[0048] Specifically, a substrate 100 is provided, a dielectric layer 101 is formed on the surface of the substrate 100, and photoresist is covered on the dielectric layer 101. The area corresponding to the deep trench 110 is exposed by exposure and development, and the deep trench 110 is formed by etching, as shown in Figure 2. An epitaxial layer 102 is grown in the deep trench 110. When the deep trench 110 is epitaxially filled to a certain extent, the outward-facing epitaxial layer 102 will cover part of the dielectric layer on the substrate surface, as shown in Figure 3, or merge and cover the dielectric layer in the entire cell position (excluding the position covering the scribe line).

[0049] The substrate 100 can be a semiconductor material such as single-crystal silicon (Si), single-crystal germanium (Ge), silicon-germanium (GeSi), or silicon carbide (SiC). The dielectric layer 101 includes a silicon nitride (Si3N4) layer and / or a silicon oxide (SiO2) layer. The temperature detector is an infrared detector connected to a temperature monitoring system, such as an FDC system (Fault Detection and Classification). The temperature detector provides the detected data to the FDC system in real time. The temperature detector can also be directly connected to the temperature detection module (Upper Temp Pyrometer) A in the FDC system. That is, an "EPI EPD" detection system was developed based on the regular changes in the EPI Upper Temp of the FDC system, which can accurately and in real time monitor the deep trench epitaxial filling degree.

[0050] In this embodiment, the substrate 100 is a silicon wafer, the dielectric layer 101 includes, but is not limited to, a silicon nitride layer and / or a silicon oxide layer, and the epitaxial layer 102 includes, but is not limited to, a single crystal silicon layer. During the epitaxial process, the substrate 100 rotates at a fixed speed, and the single crystal silicon grows simultaneously along the sidewalls and bottom of the deep trench 110. As growth continues, when the slit (V-shaped opening) at the center of the deep trench 110 closes, the epitaxial layer 102 flips outward to cover part of the substrate surface dielectric layer (covering the entire cell area). When the temperature detector detects different surface states, it will return different temperature readings.

[0051] The FDC system is set to collect data at fixed time intervals. The collected Upper Temp temperature exhibits regular fluctuations, as shown in Figure 5. In the early stage of epitaxial filling, epitaxial filling mainly occurs within the deep trench 110. The dielectric layer within the cell is not yet covered by the outward-facing epitaxial layer, and the temperature detected by the temperature detector remains within a certain temperature range, as shown in region I of Figure 5. In the later stage of epitaxial filling, the dielectric layer between the deep trenches is covered by the outward-facing epitaxial layer until the dielectric layer within the entire cell is completely covered. At this time, the temperature detected by the temperature detector shows regular fluctuations, as shown in region II of Figure 5. The degree of epitaxial filling is determined based on the temperature curve fluctuations.

[0052] Figure 6 shows the temperature curves of the fluctuating temperature detected by the temperature detector in Figure 5. Figures 7A to 7E are FA SEM images corresponding to different time periods of the temperature curves in Figure 6. Specifically, in the early stage of epitaxial filling, the epitaxial filling of the deep trench reaches point A, the central V-gate of the deep trench is not yet filled, and the dielectric layer in the cell has not yet turned outward, as shown in Figure 7A; epitaxial filling reaches point B, the central V-gate closes, and the dielectric layer in the cell has not yet turned outward, as shown in Figure 7B; epitaxial filling reaches point C, the central V-gate is filled, and the dielectric layer in the cell has not yet turned outward, as shown in Figure 7C; epitaxial filling reaches point D, the central V-gate is filled, and the dielectric layer in the cell turns outward to cover the dielectric layer on the substrate surface, as shown in Figure 7D; epitaxial filling reaches point E, the central V-gate is overfilled, and the dielectric layer in the cell turns outward to cover the dielectric layer on the substrate surface, as shown in Figure 7E.

[0053] The method for monitoring the epitaxial fill degree of deep trench superjunction MOSFET products provided in this embodiment further includes: a data module establishment program, which includes: collecting temperature data corresponding to different time periods during the epitaxial fill process of the same product, forming a correspondence between the fill process time period and temperature, and establishing a data module. For example, by collecting FA SEM data at different time periods detected by a temperature detector, it was found that when the detected temperature begins to decrease, the deep trench epitaxial fill has begun to close and has entered the final closing stage.

[0054] The method for monitoring the epitaxial fill degree of deep trench superjunction MOSFET products provided in this embodiment further includes: a data processing program, which includes: retrieving the correspondence between process time period and temperature in the data module, obtaining the real-time process time period corresponding to the real-time temperature based on the real-time temperature data detected by the temperature detector, and determining the epitaxial fill degree.

[0055] The method for monitoring the epitaxial fill degree of deep trench superjunction MOSFET products provided in this embodiment further includes an automatic epitaxial fill termination program. This program includes setting the relevant procedures for automatic termination of the epitaxial process conditions. When the temperature data detected by the temperature detector meets the conditions, the automatic termination of epitaxial fill is triggered. Specifically, the regular fluctuations in the temperature curve indicate when epitaxial fill has reached a certain stage in the process, the degree of epitaxial fill is determined, and the epitaxial recipe is terminated in a timely manner to maximize capacity utilization. Furthermore, to facilitate the determination of the epitaxial fill degree, eliminate interference from fluctuations in the original data, and facilitate the setting of trigger alarm values, the temperature data is amplified using an FDC system during temperature data collection. For example, regular curve fluctuations can be amplified. When the first regular trough appears, epitaxial fill is complete (refer to Figures 6, 7A to 7E). By setting the relevant procedures for automatic termination of process conditions through software, the process time per wafer can be reduced by 5%-20%, effectively improving the actual utilization rate and throughput of the equipment. It also helps to eliminate differences in epitaxial fill between equipment, ensuring a consistent final fill degree for the product. It should be noted that, depending on the product structure, the location of the temperature curve fluctuation indicator after the epitaxial filling is completed may vary slightly.

[0056] Specifically, the automatic termination procedure for epitaxial filling includes the following steps:

[0057] S1: Collect temperature data V at intervals t, and process the collected temperature data V, including:

[0058] S11: Take the average value X of 10 sets of temperature data: X i-1 =(V i-10 +V i-9 +V i-8 +V i-7 +V i-6 +V i-5 +V i-4 +V i-3 +V i-2 +V i-1 ) / 10, Xi=(V i-9 +V i-8 +V i-7 +V i-6 +V i-5 +V i-4 +V i-3 +V i-2 +V i-1 +V i ) / 10,

[0059] Where i > 10;

[0060] S12: Calculate the difference Δ, Δj =X i -X i-1 , where j = i - 10;

[0061] S13: Take n Δ values ​​in sequence and sum them up to S, i.e. Where k = j + n - 1, n ≥ 10, the purpose of summing over n Δ is to amplify the judgment criteria and facilitate the setting of alarm points;

[0062] S2: Judge S; when m consecutive (m≥5) S values ​​are less than the set value T, start using X. i Determine the position of the wave crest and record the corresponding step time.

[0063] Figure 8 shows the temperature curves corresponding to different process stages after temperature data processing in one embodiment of the present invention (the temperature data V, average value X, and summation S on the horizontal axis have been unified to the real-time process time point, i.e., data at the same time point). Referring to Figure 8, the temperature data is amplified, and the specific operation is as follows: At the start of the epitaxial filling process, the temperature monitoring system (e.g., EAP / FDC) collects real-time temperature data of the substrate surface, taking one data point V every 3 seconds (t=3), and taking the average value X of 10 sets of temperature data in sequence. i-1 =(V i-10 +V i-9 +V i-8 +V i-7 +V i-6 +V i-5 +V i-4 +V i-3 +V i-2 +V i-1 ) / 10, X i =(V i-9 +V i-8 +V i-7 +V i-6 +V i-5 +V i-4 +V i-3 +V i-2 +V i-1 +V i ) / 10,

[0064] Where i > 10;

[0065] Then, calculate the difference Δ, Δ j =X i -X i-1 , where j = i - 10;

[0066] Next, take 20 (n=20) Δ values ​​in sequence and sum them up to S. Where, k = j + 19;

[0067] Next, regarding S k Make a judgment when there are 5 consecutive (m=5) S k When it is less than the set value -20000 (T = -20000), that is, S k+1 <-20000&S k+2 <-20000&S k+3 <-20000&S k+4 <T-20000&S k+5 <-20000, start using X i Determine the position of the peak; if Max(X) i-3 X i-2 X i-1 X i X i+1 X i+2 X i+3 ) = X i , that is, X i The maximum value is located in the middle of 7 consecutive points (peak). Record one process time period and feed back the step time once. Continue in this way, recording N times and feeding back N step times for N peaks. Then, sequentially extract the temperature data X for each time period of the epitaxial process. i Perform peak identification. The set value T can be adjusted according to the judgment requirements.

[0068] The temperature data curve after the above signal amplification and processing is used to determine the degree of epitaxial filling based on the curve fluctuation pattern, and the epitaxial filling process is terminated in a timely manner according to the degree of filling.

[0069] Furthermore, the method for monitoring the epitaxial fill degree of deep trench superjunction MOSFET products provided by this invention can be applied to the epitaxial fill trial run (pi-run) confirmation of new products. After a new product is put into operation, a pi-run confirmation of epitaxial fill is required. Based on the temperature data obtained by the temperature detection module of the FDC system, the epitaxial fill degree can be quickly confirmed, and filling time guidance suggestions can be given.

[0070] Furthermore, the method for monitoring the epitaxial fill degree of deep trench superjunction MOSFET products provided by this invention can be applied to the detection of deep trench volume. Using the above-described method for monitoring epitaxial fill degree, temperature curves corresponding to the fill process period under the same process conditions are obtained. Based on the fluctuations of the temperature curves corresponding to the deep trench epitaxial processes etched by different etching equipment, the size of the corresponding cavity deep trench volume can be determined. Since the required epitaxial fill amount for deep trench epitaxial layers of different volumes is different, the chamber of the etching equipment can be monitored by observing the fluctuations in the obtained temperature curves.

[0071] Figure 9 shows the temperature curves of deep trench epitaxial filling etched by different etching machines using the same process (Recipe). From Figure 9, we can see the difference in the temperature curve fluctuations of CHA and CHB. The temperature curve of etching machine CHA fluctuates first, indicating that the deep trench volume of etching machine CHA is smaller than that of etching machine CHB.

[0072] The present invention also provides a computer device, including a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein the processor executes the program to implement a method for monitoring the epitaxial fill degree of a deep trench superjunction MOSFET product.

[0073] The present invention also provides a computer-readable storage medium having a computer program stored thereon, which, when executed by a processor, implements a method for monitoring the epitaxial fill degree of a deep trench superjunction MOSFET product.

[0074] This invention provides a method for monitoring the epitaxial fill degree of deep trench superjunction MOSFET products. During the epitaxial fill period, real-time temperature data of the substrate surface is acquired by a temperature detector, and the regular temperature curve fluctuations obtained by different temperature readings are fed back. The epitaxial fill degree is then judged based on the temperature curve fluctuations, thereby realizing real-time and accurate monitoring of the epitaxial fill degree of deep trench superjunction MOSFET products.

[0075] 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 method for monitoring the epitaxial fill degree of deep trench superjunction MOSFET products, characterized in that, include: A substrate with a dielectric layer on its surface is placed in a cavity with a temperature sensor, and the substrate with deep trenches is epitaxially filled in the cavity. The epitaxial filling includes growing an epitaxial layer in the deep trenches of the substrate until the epitaxial layer flips over to cover part or all of the dielectric layer on the surface of the substrate. During epitaxial filling, the temperature detector probes real-time temperature data of the substrate surface; and, The degree of epitaxial filling is monitored in real time based on the temperature data detected by the temperature detector.

2. The method for monitoring the epitaxial fill degree of deep trench superjunction MOSFET products according to claim 1, characterized in that, The dielectric layer includes a silicon nitride layer and / or a silicon oxide layer, and the epitaxial layer includes a single-crystal silicon layer.

3. The method for monitoring the epitaxial fill degree of deep trench superjunction MOSFET products according to claim 2, characterized in that, The temperature detector is an infrared detector.

4. The method for monitoring the epitaxial fill degree of deep trench superjunction MOSFET products according to claim 1, characterized in that, The temperature detector is connected to the temperature monitoring system.

5. The method for monitoring the epitaxial fill degree of deep trench superjunction MOSFET products according to claim 1, characterized in that, Also includes: The data module establishment program includes: collecting temperature data corresponding to different time periods in the epitaxial filling process of the same product, forming a correspondence between filling process time periods and temperatures, and establishing a data module.

6. The method for monitoring the epitaxial fill degree of deep trench superjunction MOSFET products according to claim 5, characterized in that, Monitoring the epitaxial fill degree of the substrate based on the temperature data detected by the temperature detector includes: a data processing program, the data processing program including: The correspondence between process time period and temperature is retrieved from the data module. Based on the real-time temperature data detected by the temperature detector, the real-time process time period corresponding to the real-time temperature is obtained, and the degree of epitaxial filling is determined.

7. The method for monitoring the epitaxial fill degree of deep trench superjunction MOSFET products according to claim 6, characterized in that, It also includes: an automatic termination procedure for epitaxial filling, wherein the automatic termination procedure for epitaxial filling includes: The process involves setting up automatic termination conditions for the epitaxial process. When the temperature data detected by the temperature detector meets the conditions, the automatic termination of the epitaxial filling is triggered.

8. The method for monitoring the epitaxial fill degree of deep trench superjunction MOSFET products according to claim 7, characterized in that, The automatic termination procedure for epitaxial filling also includes: amplifying the collected temperature data.

9. The method for monitoring the epitaxial fill degree of deep trench superjunction MOSFET products according to claim 8, characterized in that, The signal amplification process includes: S1: Collect temperature data V at intervals t, and process the collected temperature data V, including: S11: Take 10 sets of temperature data in sequence and calculate the average value X: X i-1 =(V i-10 +V i-9 +V i-8 +V i-7 +V i-6 +V i-5 +V i-4 +V i-3 +V i-2 +V i-1 ) / 10, X i =(V i-9 +V i-8 +V i-7 +V i-6 +V i-5 +V i-4 +V i-3 +V i-2 +V i-1 +V i ) / 10, Where i > 10; S12: Calculate the difference Δ, Δ j =X i -X i-1 , where j = i - 10; S13: Take n Δ values ​​in sequence and sum them up to S. Where k = j + n - 1, n ≥ 10; S2: Judge S; when m consecutive (m≥5) S values ​​are all less than the set value T, start using X. i Determine the position of the wave crest and record the corresponding process time period.

10. The method for monitoring the epitaxial fill degree of deep trench superjunction MOSFET products according to claim 9, characterized in that, Use X i Determining the peak position includes: when Max(X) i-3 X i-2 X i-1 X i X i+1 X i+2 X i+3 ) = X i X i That is, the position of the wave crest.

11. The method for monitoring the epitaxial fill degree of deep trench superjunction MOSFET products according to claim 9, characterized in that, t = 3s, n = 20, m = 5.

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