Method for Automatic Control of Deposited Film Thickness in LPCVD Furnace Tubes

Abstract

This invention provides a method for automatically controlling thin film thickness and element doping concentration within the thin film. Applied to the semiconductor process field, before and after each batch of deposition processes in a single maintenance cycle of an LPCVD furnace tube process, the dynamic target thickness of the deposited film on each monitored wafer is established based on the influence of the average patterning density of multiple different product location areas on the thickness of the deposited film on the monitored wafer. Then, based on the difference between the actual thickness of the deposited film formed on each monitored wafer and the previously established predicted thickness, the process parameters are adjusted to compensate for the film thickness impact caused by changes in the furnace tube environment. This achieves the goal of timely and dynamic adjustment of process parameters, effectively ensuring the stability of subsequent batches of LPCVD furnace tube processes.

Description

Technical Field

[0001] This invention relates to the field of semiconductor technology, and in particular to a method for automatically controlling the thickness of deposited films in an LPCVD furnace tube. Background Technology

[0002] Typically, during a maintenance cycle of the LPCVD furnace tube process (Low Pressure CVD), the thickness of the deposited film on the hot wall surfaces such as the inner wall of the reaction chamber, the outer surface of the thermocouple, and the inner wall of the downstream piping of the LPCVD furnace tube will gradually increase. This will cause changes in the internal environment of the LPCVD furnace tube, such as heat transfer efficiency, pressure control, and gas flow rate, and further affect the stability of the thickness of the green deposited film (or thin film) formed on the wafer surface.

[0003] To address this issue, the current improvement method is to manually adjust process parameters such as operation time and deposition temperature based on the difference between the film thickness grown on the monitored wafer after actual operation and the target thickness, in order to compensate for the thickness difference of the deposited film on the wafer caused by these changes.

[0004] However, in actual operation, the thickness fluctuation of the film deposited on the wafer surface is affected not only by changes in the environment inside the LPCVD furnace tube, but also by the crystal patterning density. Specifically, during the deposition reaction, the reactive gas flows from bottom to top in the reaction chamber. Placing products with high patterning density at the bottom consumes more reactive gas, resulting in less reactive gas flowing to the top, and a thinner film thickness on the upper wafer; conversely, placing products with low patterning density at the bottom results in a thicker film thickness on the upper wafer.

[0005] However, there is currently no accurate calculation method or processing method to compensate for the influence or interference of crystal patterning density on the thickness of the deposited film on the wafer surface. Therefore, finding a method to automatically control the thickness of the deposited film in the LPCVD furnace tube according to different patterning densities has become one of the technical problems that urgently need to be solved by those skilled in the art. Summary of the Invention

[0006] The purpose of this invention is to provide a method for automatically controlling the thickness of deposited films in LPCVD furnace tubes. Within a single maintenance cycle of a low-pressure chemical deposition furnace tube process (LPCVD furnace tube process), the method calculates the difference between the dynamic target thickness and the actual measured thickness of the deposited film on each monitoring plate under the influence of the average patterning density of multiple different product location areas in the LPCVD furnace tube reaction chamber within the single maintenance cycle. This allows for the adjustment of process parameters of the LPCVD furnace tube process before or after each batch of operations to compensate for the film thickness impact caused by changes in the furnace tube environment, thereby effectively ensuring the stability of subsequent batches of LPCVD furnace tube processes.

[0007] In a first aspect, to solve the above-mentioned technical problems, the present invention provides a method for automatically controlling the thickness of the deposited film in an LPCVD furnace tube, which may include at least the following steps:

[0008] An LPCVD furnace tube is provided, and the reaction chamber of the LPCVD furnace tube is divided into multiple product location areas from top to bottom;

[0009] An unpatterned monitoring panel is provided at the top, middle and bottom of the reaction chamber, wherein at least one product location area corresponds between every two monitoring panels;

[0010] Patterned wafers are filled in each product location area, and the number of wafer unit products, the location of the wafer unit products in the product placement area, the number of wafers, and the patterning density of each wafer are sent to the control system. The control system calculates the average patterning density of each product location area, and then calculates the dynamic target thickness of the deposited film on each monitoring chip through the average patterning density of different product location areas. The dynamic target thickness is the predicted thickness of the deposited film on each monitoring chip under the influence of the average patterning density of each product location area.

[0011] The corresponding process is tested on the patterned wafer, and the actual thickness of the deposited film on each monitoring wafer is measured and fed back to the control system.

[0012] The control system adjusts the process parameters based on the difference between the actual thickness of the deposited film on each monitoring chip and its dynamic target thickness. The adjusted process parameters are then used as the process parameters for the next batch of operations in the LPCVD furnace tube. The system then returns to the step of setting an unpatterned monitoring chip at the top, middle, and bottom of the reaction chamber of the LPCVD furnace tube to execute the next batch of operations.

[0013] In some optional examples, the step of calculating the dynamic target thickness of the deposited film on each monitoring chip by means of the average patterning density of different product location areas may specifically include:

[0014] Based on the pre-established actual operation sample library of the LPCVD furnace tube and the regression algorithm, the influence coefficient of the average patterning density of different product location areas of the LPCVD furnace tube on the thickness of the deposited film on each monitoring chip is calculated.

[0015] The target thickness of the deposited film on each monitoring chip and the prediction formula for its corresponding dynamic target thickness are determined. The dynamic target thickness of the deposited film on each monitoring chip is calculated under the influence of the average patterning density in the different product location areas. The target thickness of the deposited film on each monitoring chip is the design thickness value of the deposited film formed on each monitoring chip when the average patterning density in each product location area is 0.

[0016] In some of the optional examples, the regression algorithm may specifically be a partial least squares regression algorithm, which may specifically include the PLS regression algorithm.

[0017] In some optional examples, the prediction formula for the dynamic target thickness of each monitoring patch is:

[0018] TG1 ′ =TG1 + PD1*a1 + PD2*b1 + ... + PD n *m1;

[0019] TG2 ′ =TG2 + PD1*a2 + PD2*b2 + ... + PD n *m2;

[0020] TG3 ′ =TG3 + PD1*a3 + PD2*b3 + ... + PD n *m3;

[0021] Among them, TG1 ′ TG2 ′ TG3 ′ TG1, TG2, and TG3 are the dynamic target thicknesses of the deposited films formed on the monitoring chips located at the top, middle, and bottom of the reaction chamber, respectively. TG1, TG2, and TG3 are the target thicknesses of the deposited films formed on the monitoring chips located at the top, middle, and bottom of the reaction chamber when the average patterning density in each product location area is 0. PD1, PD2, ..., PD nLet a1, b1, ..., m1 be the average patterning density of the n product location areas after dividing the reaction chamber of the LPCVD furnace tube, respectively; let a1, b1, ..., m1 be the influence coefficients of the average patterning density of the n product location areas on the thickness of the deposited film on the monitoring plate set at the top of the reaction chamber; let a2, b2, ..., m2 be the influence coefficients of the average patterning density of the n product location areas on the thickness of the deposited film on the monitoring plate set in the middle of the reaction chamber; and let a3, b3, ..., m3 be the influence coefficients of the average patterning density of the n product location areas on the thickness of the deposited film on the monitoring plate set at the bottom of the reaction chamber. The condition is that n ≥ 2, m = n, and -100 < a1, b1, ..., m1, a2, b2, ..., m2, a3, a3, b3, ..., m3 < 100.

[0022] In some alternative examples, the patterning density of each product location area can be represented by the percentage of the area of ​​the feature pattern formed on the wafer using the open area of ​​a specific layer of photomask on the entire wafer.

[0023] In some of the optional examples, the patterning density of each wafer filled in each of the product location areas can specifically be 0 to 100%.

[0024] In some of the optional examples, the patterning density of the monitoring chip prior to the test run can specifically be 0.

[0025] In some optional examples, the actual working sample library of the LPCVD furnace tube may specifically include the correspondence between the actual thickness of the on-chip deposited film and the average patterning density of the different product location areas, collected through running tests.

[0026] In some of the alternative examples, the LPCVD furnace tube may specifically be an 8-inch wafer hot-wall high-temperature oxide deposition furnace.

[0027] Secondly, the present invention also provides an electronic device, specifically including a processor, a communication interface, a memory, and a communication bus, wherein the processor, the communication interface, and the memory communicate with each other through the communication bus;

[0028] Memory, used to store computer programs;

[0029] When the processor executes the program stored in the memory, it implements the steps of the method for automatically controlling the thickness of the deposited film in the LPCVD furnace tube as described above.

[0030] Thirdly, based on the same inventive concept, the present invention also provides a computer-readable storage medium storing a computer program that, when executed by a processor, implements the steps of the method for automatically controlling the thickness of the deposited film in an LPCVD furnace tube as described above.

[0031] Compared with the prior art, the technical solution of the present invention has at least one of the following beneficial effects:

[0032] In the method for automatically controlling the thickness of deposited films in LPCVD furnace tubes provided by this invention, before executing each batch of deposition processes in a single maintenance cycle of the low-pressure chemical deposition furnace tube process (hereinafter referred to as LPCVD furnace tube process), the thickness of the deposited film formed on the monitoring plates set at different product position areas is first established based on the influence law of the average patterning density of multiple different product position areas in the LPCVD furnace tube reaction chamber on the thickness of the deposited film formed on the monitoring plates set at different product position areas. Then, the predicted thickness (dynamic target thickness) of the deposited film formed on each monitoring plate under the influence of the average patterning density of different product position areas is established. Then, the LPCVD furnace tube process is performed. Afterwards, based on LPCVD… The difference between the actual thickness of the deposited film formed on each monitoring plate after the LPCVD furnace tube process and the previously established predicted thickness (dynamic target thickness) is used to adjust the process parameters of the LPCVD furnace tube process. This compensates for the influence of film thickness caused by changes in the furnace tube environment. In turn, by monitoring the thickness of the deposited film formed on the monitoring plates set at different product location areas in the previous batch of LPCVD furnace tube process based on the average patterning density of multiple different product location areas, the goal of timely and dynamic adjustment of the LPCVD furnace tube process parameters can be achieved, thereby effectively ensuring the stability of the LPCVD furnace tube process in subsequent batches. Attached Figure Description

[0033] Figure 1 This is a schematic diagram of the LPCVD furnace tube, monitoring chip, and wafer arrangement provided in some embodiments of the present invention.

[0034] Figure 2 This is a schematic flowchart of a method for automatically controlling the thickness of deposited films in an LPCVD furnace tube, provided in some embodiments of the present invention.

[0035] Figure 3 Provided in some embodiments of the present invention Figure 1 The graph shows the correlation between the average patterning density of different product location areas and the thickness of the deposited film formed on the first monitoring wafer 1, as shown by the LPCVD furnace tube, monitoring wafer, and wafer setup.

[0036] Figure 4 Provided in some embodiments of the present invention Figure 1The graph shows the correlation between the average patterning density of different product location areas and the thickness of the deposited film formed on the second monitoring wafer 2, as shown by the LPCVD furnace tube, monitoring wafer, and wafer setup.

[0037] Figure 5 Provided in some embodiments of the present invention Figure 1 The graph shows the correlation between the average patterning density of different product location areas and the thickness of the deposited film formed on the third monitoring wafer 3, as shown by the LPCVD furnace tube, monitoring wafer, and wafer setup. Detailed Implementation

[0038] The method for automatically controlling the thickness of the deposited film in an LPCVD furnace tube, as 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. 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. Many specific details are set forth in the following description to provide a thorough understanding of this invention; however, this invention can also be implemented in other ways different from those described herein, and therefore this invention is not limited to the specific embodiments disclosed below.

[0039] As shown in this application and claims, unless the context clearly indicates otherwise, the words "a," "an," "an," and / or "the" do not specifically refer to the singular and may also include the plural. Generally speaking, the terms "comprising" and "including" only indicate the inclusion of explicitly identified steps and elements, which do not constitute an exclusive list, and the method or apparatus may also include other steps or elements. In detailing the embodiments of the present invention, for ease of explanation, the cross-sectional views showing the device structure may be partially enlarged without adhering to the general scale, and the schematic diagrams are merely examples and should not limit the scope of protection of the present invention. Furthermore, in actual manufacturing, the three-dimensional spatial dimensions of length, width, and depth should be included.

[0040] See Figures 1-2 , Figure 1 This is a schematic diagram illustrating the LPCVD furnace tube, monitoring wafer, and wafer arrangement provided in some embodiments of the present invention. Figure 2 This is a schematic flowchart of a method for automatically controlling the thickness of deposited films in an LPCVD furnace tube, provided in some embodiments of the present invention.

[0041] It should be noted that in actual LPCVD furnace tube processes, there are various types of operating equipment that can be used, such as... Figure 1 The 8-inch wafer hot-wall high-temperature oxide deposition furnace shown can be divided into multiple product placement areas from top to bottom according to the size of the reaction chamber of each different operating device, such as... Figure 1The product positions 1, 2, 3, and 4 shown are used to place multiple wafers to be processed by LPCVD furnace tube technology. Each wafer can be a patterned wafer with a specific pattern formed on its surface. Figure 1 The multiple product locations in the diagram are the product location areas described in this embodiment of the invention.

[0042] Based on the characteristics of the LPCVD furnace tube process, it is known that within a maintenance cycle, the thickness of the deposited film on the hot-wall surfaces of the LPCVD furnace tube, such as the inner wall of the reaction chamber, the outer surface of the thermocouple, and the inner wall of the downstream piping, will gradually accumulate. This will affect changes in the LPCVD furnace tube environment, such as heat transfer efficiency, pressure control, and gas flow rate, and further affect the stability of the thickness of the deposited film (or thin film) formed on the wafer surface. Moreover, the fluctuation in the thickness of the deposited film on the wafer surface is affected not only by changes in the LPCVD furnace tube environment but also by the crystal patterning density.

[0043] Therefore, the current method of adjusting process parameters such as operation time and deposition temperature based on the difference between the film thickness grown on the monitoring wafer after actual operation only considers the process parameters of environmental changes, but does not consider the improvement of the thickness difference of the film deposited on the wafer caused by the fluctuation of the crystal patterning density. This will instead lead to inaccurate adjustment and large fluctuations in the film thickness of subsequent batches.

[0044] To address this problem, the main inventive concept of this invention is to isolate and study the influence or interference of crystal patterning density on the thickness of the deposited film on the wafer surface. Specifically, this involves studying the influence of the average patterning density of multiple different product location areas in the LPCVD furnace tube reaction chamber on the thickness of the deposited film formed on the monitoring wafers located at different product location areas. Based on this study, the difference between the dynamic target thickness and the actual measured thickness of the deposited film formed on each monitoring wafer under the influence of the average patterning density of different product location areas in the LPCVD furnace tube reaction chamber is obtained. Thus, the invention proposes a process parameter adjustment method that can accurately compensate for changes in the furnace tube environment of the LPCVD furnace tube process after or before each batch operation, thereby effectively ensuring the stability of the LPCVD furnace tube process in subsequent batches. This is the method for automatically controlling the thickness of the deposited film in the LPCVD furnace tube as described in the embodiments of this invention.

[0045] To simplify the description, the following text will use the format of... Figure 1 The 8-inch wafer hot-wall high-temperature oxide deposition furnace shown is an example of the operating equipment. Figure 2 The automatic control method shown will be introduced.

[0046] like Figure 2As shown, the method for automatically controlling the deposition film thickness of the LPCVD furnace tube provided in this embodiment of the invention may specifically include:

[0047] Step S201: Provide an LPCVD furnace tube and divide the reaction chamber of the LPCVD furnace tube into multiple product location areas from top to bottom.

[0048] In this embodiment, as Figure 1 The 8-inch wafer hot-wall high-temperature oxide deposition furnace shown can be divided into four product location zones from top to bottom for this furnace tube (corresponding to...). Figure 1 The four product locations are each designated as a product location, and each product location can accommodate multiple patterned wafers. Each patterned wafer has a patterning density, meaning that each product location corresponds to an average patterning density.

[0049] Step S202: An unpatterned monitoring plate is respectively set at the top, middle and bottom of the reaction chamber, wherein at least one product position area corresponds between every two monitoring plates.

[0050] In this embodiment, regardless of the size or type of LPCVD furnace tube, a three-end control plate is used as a film thickness measuring plate to monitor the growth thickness of particles and deposited film in the entire batch. That is, a monitoring plate is set at the top, middle and bottom of the reaction chamber of the LPCVD furnace tube, which is the operating equipment of the LPCVD furnace tube process, and the patterning density of each monitoring plate is 0.

[0051] The patterning density of each product location area can be represented by the area of ​​the feature pattern formed on the wafer using the open area of ​​a specific layer of photomask as a percentage of the total area of ​​the wafer.

[0052] As a preferred example, such as Figure 1 As shown, the three-terminal control plate used in this invention is specifically a control plate 1 set above product position 1, a control plate 2 set between product position 2 and product position 3, and a control plate 3 set below product position 4.

[0053] Understandable, Figure 1 The three monitoring plates shown are located at the ends of different product location areas, which is one example. For other types of LPCVD furnace tubes, one or more of the three end control plates (three monitoring plates) used in this invention may also be placed at the ends of one or more product location areas, while the remaining one or more monitoring plates may be placed in a certain area in the middle of the product location area. That is, as long as three monitoring plates are placed, their specific corresponding setting positions in the product location area are not specifically limited.

[0054] Based on this theory, the number of product location areas corresponding to any two monitoring chips in the embodiments of the present invention can be the same or different, for example, they can be as follows: Figure 1 As shown, two product positions (i.e., product position areas) are set between control plate 1, control plate 2, and control plate 2 and control plate 3. In other examples, different product position areas can also be set.

[0055] Step S203: Patterned wafers are filled in each product location area, and the number of wafer unit products, the position of the wafer unit product in the product placement area, the number of wafers, and the patterning density of each wafer are sent to the control system. The control system calculates the average patterning density of each product location area, and then calculates the dynamic target thickness of the deposited film on each monitoring chip through the average patterning density of different product location areas. The dynamic target thickness is the predicted thickness of the deposited film on each monitoring chip under the influence of the average patterning density of each product location area.

[0056] In this embodiment, after dividing the LPCVD furnace tube into product location areas and setting monitoring plates, multiple patterned wafers can be filled into each product location area. That is, a certain pattern is formed on the surface of each wafer, so that it has a pattern density. The pattern of the wafer has a certain influence on the thickness of the deposited film (or thin film) to be formed in the LPCVD furnace tube process to be performed.

[0057] For example, the patterning density of each wafer filled in each of the product location areas is 0-25%.

[0058] Therefore, it is necessary to determine the influence of the patterning density of multiple patterned wafers placed in each product location area on the thickness of the deposited film to be formed on the patterned wafers placed in this area and other product location areas. In order to facilitate the solution, the embodiments of the present invention utilize the average patterning density of multiple patterned wafers placed in each product location area (referred to as the average patterning density of the product location area) to monitor the thickness of the deposited film formed on the monitoring chip set in different product location areas, thereby achieving the monitoring of the thickness of the deposited film to be formed on the wafer.

[0059] As a preferred example, the present invention provides a specific implementation method for calculating the dynamic target thickness of the deposited film on each monitoring chip by means of the average patterning density of different product location areas, which may include the following steps:

[0060] Step S203.1: Based on the pre-established actual operation sample library of the LPCVD furnace tube and the regression algorithm, calculate the influence coefficient of the average patterning density of different product location areas of the LPCVD furnace tube on the thickness of the deposited film on each monitoring chip.

[0061] Step S203.2: Determine the target thickness of the deposited film on each monitoring chip and the prediction formula for its corresponding dynamic target thickness, and calculate the dynamic target thickness of the deposited film on each monitoring chip under the influence of the average patterning density in the different product location areas, wherein the target thickness of the deposited film on each monitoring chip is the design thickness value of the deposited film formed on each monitoring chip when the average patterning density in each product location area is 0.

[0062] The regression algorithm is a partial least squares regression algorithm, which includes the PLS regression algorithm.

[0063] In this embodiment, a real-world sample library of LPCVD furnace tubes can be established by establishing the correspondence between the actual thickness of the deposited film on each monitoring chip collected during the product testing and the average patterning density of the different product location areas. Then, using the correspondence in this real-world sample library combined with the PLS regression algorithm, a model is constructed to obtain a functional relationship with the average patterning density of different product location areas as the independent variable and the thickness of the deposited film on different monitoring chips as the dependent variable. After conversion, the influence coefficient of the average patterning density of different product location areas on the thickness of the deposited film formed on different monitoring chips is obtained, thereby obtaining the prediction formula for the dynamic target thickness of each monitoring chip provided in this embodiment of the invention.

[0064] The prediction formula for the dynamic target thickness of each monitoring segment provided in this embodiment of the invention is as follows:

[0065] TG1 ′ =TG1 + PD1*a1 + PD2*b1 + ... + PD n *m1 (1)

[0066] TG2 ′ =TG2 + PD1*a2 + PD2*b2 + ... + PD n *m2 (2)

[0067] TG3 ′ =TG3 + PD1*a3 + PD2*b3 + ... + PD n *m3 (3)

[0068] Among them, TG1 ′ TG2 ′ TG3 ′TG1, TG2, and TG3 are the dynamic target thicknesses of the deposited films formed on the monitoring chips located at the top, middle, and bottom of the reaction chamber, respectively. TG1, TG2, and TG3 are the target thicknesses of the deposited films formed on the monitoring chips located at the top, middle, and bottom of the reaction chamber when the average patterning density in each product location area is 0. PD1, PD2, ..., PD n Let a1, b1, ..., m1 be the average patterning density of the n product location areas after dividing the reaction chamber of the LPCVD furnace tube, respectively; let a1, b1, ..., m1 be the influence coefficients of the average patterning density of the n product location areas on the thickness of the deposited film on the monitoring plate set at the top of the reaction chamber; let a2, b2, ..., m2 be the influence coefficients of the average patterning density of the n product location areas on the thickness of the deposited film on the monitoring plate set in the middle of the reaction chamber; and let a3, b3, ..., m3 be the influence coefficients of the average patterning density of the n product location areas on the thickness of the deposited film on the monitoring plate set at the bottom of the reaction chamber. The condition is that n ≥ 2, m = n, and -100 < a1, b1, ..., m1, a2, b2, ..., m2, a3, a3, b3, ..., m3 < 100.

[0069] In one example, the average patterning density of each product location area of ​​the LPCVD furnace tube has a certain influence on the thickness of the deposited film formed on each monitoring plate set therein. Therefore, at this time, any thickness influence coefficient in the prediction formulas (1) to (3) of the dynamic target thickness of each monitoring plate mentioned above is not 0, that is, a1, b1, ..., m1, a2, b2, ..., m2, a3, a3, b3, ..., m3 are not 0.

[0070] In another example, only the average patterning density of a portion of the product location area of ​​the LPCVD furnace tube has a certain influence on the thickness of the deposited film formed on each monitoring plate set therein. Therefore, at this time, one or more thickness influence coefficients in the prediction formulas (1) to (3) for the dynamic target thickness of each monitoring plate mentioned above are 0, that is, one or more of the thickness influence coefficients a1, b1, ..., m1 of the deposited film set on the monitoring plate set at the top of the reaction chamber are 0, one or more of the thickness influence coefficients a2, b2, ..., m2 of the deposited film set on the monitoring plate set in the middle of the reaction chamber are 0, and one or more of the thickness influence coefficients a3, a3, b3, ..., m3 of the deposited film set on the monitoring plate set in the middle of the reaction chamber are 0.

[0071] For ease of understanding, the following will be explained through... Figure 1Taking the LPCVD furnace tube shown as an example, the prediction formula for the dynamic target thickness of each monitoring piece will be explained.

[0072] like Figure 1 As shown, the LPCVD furnace tube has 4 product positions (or product position areas), and the corresponding three-end control plates are control plate 1 above product position 1, control plate 2 between product position 2 and product position 3, and control plate 3 below product position 4. The prediction formulas (1) to (3) for the dynamic target thickness of each monitoring plate are as follows:

[0073] TG1 ′ =TG1+PD1*a1+PD2*b1+PD3*c1+PD4*d1;

[0074] TG2 ′ =TG2+PD1*a2+PD2*b2+PD3*c2+PD4*d2;

[0075] TG3 ′ =TG3+PD1*a3+PD2*b3+PD3*c3+PD4*d4;

[0076] For the control chip 1, a1 is Figure 1 The influence coefficient of product location 1 on the thickness of the deposited film formed thereon is shown, where b1 is... Figure 1 The influence coefficient of product location 2 on the thickness of the deposited film formed thereon is shown, c1 is Figure 1 The influence coefficient of product location 3 on the thickness of the deposited film formed thereon is shown, where d1 is... Figure 1 The influence coefficient of product location 2 on the thickness of the deposited film formed on it.

[0077] See Figures 3-5 ,according to Figures 3-5 As shown in the correlation curve, if the average patterning density of the four product positions in the LPCVD furnace tube has a certain influence on the thickness of the deposited film formed on the three monitoring plates set inside, then a1, b1, c1, and d1 are all not 0. Similarly, the same applies to control plates 2 and 3.

[0078] in, Figures 3-5 In the diagram, the thickness of control piece 1 / 2 / 3 is the dynamic target thickness of control piece 1, control piece 2, and control piece 2, and the product pattern density at positions 1 / 2 / 3 / 4 is... Figure 1 The average patterning density of product positions 1, 2, 3, and 4 is shown.

[0079] If only the average patterning density of a portion of the product location area in the LPCVD furnace tube has a certain impact on the thickness of the deposited film formed on each monitoring chip set therein, then for control chip 1, a1 is not 0, while b1, c1, and d1 are all 0; for control chip 2, d1 is 0, while a1, b1, and c1 are all not 0; and for control chip 3, a1, b1, c1, and d1 are all not 0.

[0080] Step S204: Perform corresponding process testing on the patterned wafer, measure the actual thickness of the deposited film on each monitoring wafer, and feed it back to the control system.

[0081] In step S205, the control system adjusts the process parameters based on the difference between the actual thickness of the deposited film on each monitoring chip and its dynamic target thickness, and uses the adjusted process parameters as the process parameters for the next batch of operations in the LPCVD furnace tube. The system then returns to the step of setting an unpatterned monitoring chip at the top, middle and bottom of the reaction chamber of the LPCVD furnace tube to execute the next batch of operations.

[0082] Furthermore, the control method provided in this embodiment of the invention may include a step of setting other relevant coefficients of the control system before performing the LPCVD furnace tube process. This is prior art, and the present invention does not specifically limit it.

[0083] In summary, in the method for automatically controlling the thickness of deposited films in LPCVD furnace tubes provided by this invention, before executing each batch of deposition processes in a single maintenance cycle of the low-pressure chemical deposition furnace tube process (hereinafter referred to as LPCVD furnace tube process), the method first establishes the predicted thickness (dynamic target thickness) of the deposited film formed on each monitoring plate under the influence of the average patterning density of multiple different product location areas in the LPCVD furnace tube reaction chamber on the thickness of the deposited film formed on the monitoring plate set at different product location areas, based on the influence law of the average patterning density of different product location areas. Then, the LPCVD furnace tube process is performed, and subsequently, based on L... The difference between the actual thickness of the deposited film formed on each monitoring plate after the PCVD furnace tube process and the previously established predicted thickness (dynamic target thickness) is used to adjust the process parameters of the LPCVD furnace tube process. This compensates for the influence of changes in the furnace tube environment on the film thickness. In turn, by monitoring the average patterning density of multiple different product location areas in the previous batch of LPCVD furnace tube process, the thickness of the deposited film formed on the monitoring plates set at different product location areas can be monitored. This achieves the goal of timely and dynamic adjustment of the process parameters of the LPCVD furnace tube process, thereby effectively ensuring the stability of the LPCVD furnace tube process in subsequent batches.

[0084] Furthermore, embodiments of the present invention also provide an electronic device, including a processor, a communication interface, a memory, and a communication bus, wherein the processor, the communication interface, and the memory communicate with each other via the communication bus.

[0085] Memory, used to store computer programs;

[0086] The processor, when executing the program stored in the memory, implements the method for automatically controlling the thickness of the deposited film in the LPCVD furnace tube provided in the embodiments of the present invention.

[0087] Specifically, the method for automatically controlling the thickness of the deposited film in the LPCVD furnace tube may include:

[0088] An LPCVD furnace tube is provided, and the reaction chamber of the LPCVD furnace tube is divided into multiple product location areas from top to bottom;

[0089] An unpatterned monitoring panel is provided at the top, middle and bottom of the reaction chamber, wherein at least one product location area corresponds between every two monitoring panels;

[0090] Patterned wafers are filled in each product location area, and the number of wafer unit products, the location of the wafer unit products in the product placement area, the number of wafers, and the patterning density of each wafer are sent to the control system. The control system calculates the average patterning density of each product location area, and then calculates the dynamic target thickness of the deposited film on each monitoring chip through the average patterning density of different product location areas. The dynamic target thickness is the predicted thickness of the deposited film on each monitoring chip under the influence of the average patterning density of each product location area.

[0091] The corresponding process is tested on the patterned wafer, and the actual thickness of the deposited film on each monitoring wafer is measured and fed back to the control system.

[0092] The control system adjusts the process parameters based on the difference between the actual thickness of the deposited film on each monitoring chip and its dynamic target thickness. The adjusted process parameters are then used as the process parameters for the next batch of operations in the LPCVD furnace tube. The system then returns to the step of setting an unpatterned monitoring chip at the top, middle, and bottom of the reaction chamber of the LPCVD furnace tube to execute the next batch of operations.

[0093] In addition, other implementations of the method steps for automatically controlling the thickness of the deposited film in an LPCVD furnace tube by the processor executing the program stored in the memory are the same as those mentioned in the aforementioned method embodiment section, and will not be repeated here.

[0094] The communication bus mentioned in the control terminal above can be a Peripheral Component Interconnect (PCI) bus or an Extended Industry Standard Architecture (EISA) bus, etc. This communication bus can be divided into address bus, data bus, control bus, etc. For ease of illustration, only one thick line is used to represent it in the diagram, but this does not indicate that there is only one bus or one type of bus.

[0095] The communication interface is used for communication between the aforementioned electronic devices and other devices.

[0096] The memory may include random access memory (RAM) or non-volatile memory (NVM), such as at least one disk storage device. Optionally, the memory may also be at least one storage device located remotely from the aforementioned processor.

[0097] The processors mentioned above can be general-purpose processors, including central processing units (CPUs), network processors (NPs), etc.; they can also be digital signal processors (DSPs), application-specific integrated circuits (ASICs), field-programmable gate arrays (FPGAs), or other programmable logic devices, discrete gate or transistor logic devices, or discrete hardware components.

[0098] In another embodiment of the present invention, a computer-readable storage medium is also provided, which stores instructions that, when executed on a computer, cause the computer to perform the method for automatically controlling the thickness of the deposited film in the LPCVD furnace tube as described in any of the above embodiments.

[0099] In the above embodiments, implementation can be achieved entirely or partially through software, hardware, firmware, or any combination thereof. When implemented using software, it can be implemented entirely or partially in the form of a computer program product. The computer program product includes one or more computer instructions. When the computer program instructions are loaded and executed on a computer, all or part of the processes or functions described in the embodiments of the present invention are generated. The computer can be a general-purpose computer, a special-purpose computer, a computer network, or other programmable device. The computer instructions can be stored in a computer-readable storage medium or transmitted from one computer-readable storage medium to another. For example, the computer instructions can be transmitted from one website, computer, server, or data center to another website, computer, server, or data center via wired (e.g., coaxial cable, fiber optic, digital subscriber line (DSL)) or wireless (e.g., infrared, wireless, microwave, etc.) means. The computer-readable storage medium can be any available medium that a computer can access or a data storage device such as a server or data center that integrates one or more available media. The available medium can be a magnetic medium (e.g., floppy disk, hard disk, magnetic tape), an optical medium (e.g., DVD), or a semiconductor medium (e.g., solid state disk (SSD)).

[0100] It should be noted that, in this document, relational terms such as "first" and "second" are used only to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitations, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes said element.

[0101] The various embodiments in this specification are described in a related manner. Similar or identical parts between embodiments can be referred to mutually. Each embodiment focuses on describing the differences from other embodiments. In particular, the embodiments of apparatus, electronic devices, and computer-readable storage media are basically similar to the method embodiments, and therefore the descriptions are relatively simple; relevant parts can be referred to the descriptions of the method embodiments.

[0102] The above description is merely a preferred embodiment of the present invention and is not intended to limit the scope of protection of the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention are included within the scope of protection of the present invention.

Claims

1. A method for automatically controlling the thickness of deposited films in an LPCVD furnace tube, characterized in that, include: An LPCVD furnace tube is provided, and the reaction chamber of the LPCVD furnace tube is divided into multiple product location areas from top to bottom; An unpatterned monitoring panel is provided at the top, middle and bottom of the reaction chamber, wherein at least one product location area corresponds between every two monitoring panels; Patterned wafers are filled in each product location area, and the number of wafer unit products, the location of the wafer unit products in the product placement area, the number of wafers, and the patterning density of each wafer are sent to the control system. The control system calculates the average patterning density of each product location area, and then calculates the dynamic target thickness of the deposited film on each monitoring chip through the average patterning density of different product location areas. The dynamic target thickness is the predicted thickness of the deposited film on each monitoring chip under the influence of the average patterning density of each product location area. The corresponding process is tested on the patterned wafer, and the actual thickness of the deposited film on each monitoring wafer is measured and fed back to the control system. The control system adjusts the process parameters based on the difference between the actual thickness of the deposited film on each monitoring chip and its dynamic target thickness. The adjusted process parameters are then used as the process parameters for the next batch of operations in the LPCVD furnace tube. The system then returns to the step of setting an unpatterned monitoring chip at the top, middle, and bottom of the reaction chamber of the LPCVD furnace tube to execute the next batch of operations.

2. The method for automatically controlling the thickness of the deposited film in an LPCVD furnace tube as described in claim 1, characterized in that, The step of calculating the dynamic target thickness of the deposited film on each monitoring chip by means of the average patterning density in different product location areas includes: Based on the pre-established actual operation sample library of the LPCVD furnace tube and the regression algorithm, the influence coefficient of the average patterning density of different product location areas of the LPCVD furnace tube on the thickness of the deposited film on each monitoring chip is calculated. The target thickness of the deposited film on each monitoring chip and the prediction formula for its corresponding dynamic target thickness are determined. The dynamic target thickness of the deposited film on each monitoring chip is calculated under the influence of the average patterning density in the different product location areas. The target thickness of the deposited film on each monitoring chip is the design thickness value of the deposited film formed on each monitoring chip when the average patterning density in each product location area is 0.

3. The method for automatically controlling the thickness of the deposited film in an LPCVD furnace tube as described in claim 2, characterized in that, The regression algorithm is a partial least squares regression algorithm, which includes the PLS regression algorithm.

4. The method for automatically controlling the thickness of the deposited film in an LPCVD furnace tube as described in claim 3, characterized in that, The prediction formula for the dynamic target thickness of each monitoring cell is as follows: TG1 ′ =TG1+PD1*a1+PD2*b1+...+PD n *m1; TG2 ′ =TG2+PD1*a2+PD2*b2+...+PD n *m2; TG3 ′ =TG3+PD1*a3+PD2*b3+...+PD n *m3; Among them, TG1 ′ TG2 ′ TG3 ′ TG1, TG2, and TG3 are the dynamic target thicknesses of the deposited films formed on the monitoring chips located at the top, middle, and bottom of the reaction chamber, respectively. TG1, TG2, and TG3 are the target thicknesses of the deposited films formed on the monitoring chips located at the top, middle, and bottom of the reaction chamber when the average patterning density in each product location area is 0. PD1, PD2, ..., PD n Let a1, b1, ..., m1 be the average patterning density of the n product location areas after dividing the reaction chamber of the LPCVD furnace tube, respectively; let a1, b1, ..., m1 be the influence coefficients of the average patterning density of the n product location areas on the thickness of the deposited film on the monitoring plate set at the top of the reaction chamber; let a2, b2, ..., m2 be the influence coefficients of the average patterning density of the n product location areas on the thickness of the deposited film on the monitoring plate set in the middle of the reaction chamber; and let a3, b3, ..., m3 be the influence coefficients of the average patterning density of the n product location areas on the thickness of the deposited film on the monitoring plate set at the bottom of the reaction chamber. The condition is that n ≥ 2, m = n, and -100 < a1, b1, ..., m1, a2, b2, ..., m2, a3, a3, b3, ..., m3 < 100.

5. The method for automatically controlling the thickness of the deposited film in an LPCVD furnace tube as described in claim 1, characterized in that, The patterning density of each product location area can be represented by the proportion of the area of ​​the feature pattern formed on the wafer using the open area of ​​a specific layer of photomask on the entire wafer.

6. The method for automatically controlling the thickness of the deposited film in an LPCVD furnace tube as described in claim 5, characterized in that, The patterning density of each wafer filled in each of the product location areas is 0-100%.

7. The method for automatically controlling the thickness of the deposited film in an LPCVD furnace tube as described in claim 5, characterized in that, The patterning density of the monitoring chip was 0 before the test run.

8. The method for automatically controlling the thickness of the deposited film in an LPCVD furnace tube as described in claim 2, characterized in that, The actual operational sample library of the LPCVD furnace tube includes the correspondence between the actual thickness of the deposited film on each monitoring chip and the average patterning density of the different product location areas, collected through product testing.

9. The method for automatically controlling the thickness of the deposited film in an LPCVD furnace tube as described in claim 1, characterized in that, The LPCVD furnace tube includes an 8-inch wafer hot-wall high-temperature oxide deposition furnace.

10. An electronic device, characterized in that, It includes a processor, a communication interface, a memory, and a communication bus, wherein the processor, the communication interface, and the memory communicate with each other through the communication bus; Memory, used to store computer programs; When a processor executes a program stored in a memory, it implements the steps of the method for automatically controlling the thickness of the deposited film in an LPCVD furnace tube as described in any one of claims 1 to 9.

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