Methods and systems for improving wafer coating uniformity

Abstract

This disclosure provides a method and system for improving the uniformity of wafer coating. The method includes: providing a coating apparatus; providing a wafer, the coating apparatus being used to coat the wafer; monitoring the current in different regions of the wafer surface during the coating process; inspecting the coating apparatus when the difference in current between different regions of the wafer surface exceeds a preset difference; and cleaning the coating apparatus when there are deposits on it. This technical solution, by monitoring the current in different regions of the wafer surface during the coating process, can promptly detect areas of uneven coating on the wafer surface; inspecting the coating apparatus when the difference in current between different regions of the wafer surface exceeds a preset difference to identify components requiring maintenance; and cleaning the coating apparatus when there are deposits, thereby improving the uniformity of the wafer coating.

Description

Technical Field

[0001] This application relates to the field of semiconductor manufacturing, and in particular to methods and systems for improving the uniformity of wafer coating. Background Technology

[0002] Electroplating on a wafer typically involves immersing the wafer in an electrolytic cell containing an ionic solution that allows current to flow from a metal rod (acting as the anode) to the wafer (acting as the cathode). The current ionizes the metal and is conducted through the electroplating equipment to the wafer surface, forming a thin, solid metal film.

[0003] However, due to continuous technological advancements, the metal film deposited on the wafer edges is becoming increasingly thin. If there is metal residue in the area where the electroplating equipment contacts the wafer surface, it will cause inconsistent current conduction to the wafer surface, resulting in the wafer edges not being plated or having a thinner film, which will affect the process and lead to wafer scrap.

[0004] Therefore, improving the uniformity of wafer coating is a technical problem that needs to be solved. Summary of the Invention

[0005] The technical problem to be solved by this disclosure is to provide a method and system for improving the uniformity of wafer coating, so as to improve the uniformity of wafer coating.

[0006] To address the aforementioned problems, this disclosure provides a method for improving wafer coating uniformity, comprising: providing a coating apparatus; providing a wafer, the coating apparatus being used to coat the wafer; during the coating process, monitoring the current in different regions of the wafer surface; when the difference in current in different regions of the wafer surface exceeds a preset difference, inspecting the coating apparatus; and when there are deposits on the coating apparatus, cleaning the coating apparatus.

[0007] In some embodiments, the method for improving wafer coating uniformity further includes: setting a plurality of concentric current loops on the coating equipment; when the difference in current between two current loops is greater than a preset difference, determining that the difference in current in different regions of the wafer surface is greater than the preset difference.

[0008] In some embodiments, the preset difference includes the difference in current between the two current loops during the previous wafer deposition.

[0009] In some embodiments, the method for improving wafer coating uniformity further includes: inspecting the coating equipment when the current in one or more of the current loops is greater than a preset standard current.

[0010] In some embodiments, the preset standard current includes the current on the wafer surface during the previous wafer coating process.

[0011] In some embodiments, the method for improving wafer coating uniformity further includes: setting a plurality of data monitoring points on the current loop, and using the average current of the data monitoring points as the current value of the current loop.

[0012] In some embodiments, monitoring the current in different regions of the wafer surface includes: dividing the wafer surface into multiple regions; setting multiple data monitoring points in each region; and using the average current of the data monitoring points as the current of that region.

[0013] In some embodiments, the method for improving wafer coating uniformity further includes: coating the next wafer when the difference in current between different regions on the wafer surface is less than a preset difference.

[0014] In some embodiments, the method for improving wafer coating uniformity further includes: inspecting the parts used for coating with a high-magnification microscope.

[0015] In some embodiments, cleaning the coating equipment includes cleaning the coating needles.

[0016] In some embodiments, cleaning the coating needle includes: immersing the coating needle in an alkaline solution; rinsing the coating needle with clean water; immersing the coating needle in a mixture of an acidic solution and hydrogen peroxide for more than 30 minutes; and rinsing the coating needle with clean water.

[0017] In some embodiments, the alkaline solution is ammonia water with a concentration of 10% to 30%, and the acidic solution is sulfuric acid.

[0018] In some embodiments, the volume ratio of sulfuric acid, hydrogen peroxide, and water in the mixture is (1-2):(2-4):(5-7), the concentration of sulfuric acid is 90%-99%, and the concentration of hydrogen peroxide is 20%-40%.

[0019] This disclosure also provides a system for improving the uniformity of wafer coating, comprising: a coating apparatus; a wafer, the coating apparatus being used to coat the wafer; a detection module for monitoring the current in different regions of the wafer surface during the coating process; a judgment module for inspecting the coating apparatus when the difference in current in different regions of the wafer surface is greater than a preset difference; and a cleaning module for cleaning the coating apparatus when there are deposits on it.

[0020] The above technical solution, by monitoring the current in different areas of the wafer surface during the coating process, can promptly detect areas of uneven coating on the wafer surface. When the difference in current between different areas of the wafer surface exceeds a preset difference, the coating equipment is inspected to identify components requiring maintenance. When there are deposits on the coating equipment, the equipment is cleaned to prevent these deposits from affecting the current conducted from the coating equipment to the wafer surface, thereby improving the uniformity of wafer coating.

[0021] It should be understood that the above general description and the following detailed description are exemplary and explanatory only, and are not intended to limit this disclosure. Techniques, methods, and apparatus known to those skilled in the art may not be discussed in detail, but where appropriate, such techniques, methods, and apparatus should be considered part of the specification. Attached Figure Description

[0022] To more clearly illustrate the technical solutions of the embodiments of this application, the drawings used in the embodiments of this application will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0023] Figure 1 This is a schematic diagram of a method for improving wafer coating uniformity according to the first embodiment of this disclosure.

[0024] Figure 2 This is a schematic diagram of the coating apparatus in the first embodiment of this disclosure.

[0025] Figure 3 This is a schematic diagram of a method for improving wafer coating uniformity according to an embodiment of the present disclosure.

[0026] Figure 4 This is a schematic diagram of the division of the wafer surface region in the second embodiment of this disclosure.

[0027] Figure 5 This is a schematic diagram of a method for cleaning a coating needle according to an embodiment of the present disclosure.

[0028] Figure 6 This is a graph showing the relationship between soaking time and number of cleaning cycles when using only a mixed solution to clean the coating needle in one embodiment of this disclosure.

[0029] Figure 7 This is a graph showing the relationship between soaking time and number of cleaning cycles when using only ammonia water to clean the coating needle in one embodiment of this disclosure.

[0030] Figure 8This is a graph showing the relationship between the soaking time and the number of cleaning cycles when cleaning the coating needle with ammonia water and then a mixed solution in one embodiment of this disclosure.

[0031] Figure 9 This is a schematic diagram of a system for improving wafer coating uniformity according to an embodiment of the present disclosure. Detailed Implementation

[0032] The following detailed description, in conjunction with the accompanying drawings, provides a method for improving wafer coating uniformity according to the present disclosure. The following description of at least one exemplary embodiment is merely illustrative and is not intended to limit the scope of the present disclosure or its application or use. That is, those skilled in the art will understand that they merely illustrate exemplary methods that can be used in practice, and not exhaustive methods. Furthermore, unless otherwise specifically stated, the relative arrangement of components and steps set forth in these embodiments does not limit the scope of the present disclosure.

[0033] Figure 1 This is a schematic diagram of a method for improving wafer coating uniformity according to a first embodiment of the present disclosure. The method for improving wafer coating uniformity includes: step S101, providing a coating apparatus; step S102, providing a wafer, wherein the coating apparatus is used to coat the wafer; step S103, during the coating process, monitoring the current in different regions of the wafer surface; step S104, when the difference in current in different regions of the wafer surface is greater than a preset difference, inspecting the coating apparatus; and step S105, when there are deposits on the coating apparatus, cleaning the coating apparatus.

[0034] Please continue reading below. Figure 1 Step S101: Provide coating equipment. Figure 2 This is a schematic diagram of the coating apparatus according to the first embodiment of this disclosure. Please refer to the following: Figure 2 The coating equipment includes a coating chamber 1 and multiple coating needles 2. The coating chamber 1 contains an ionic solution. Current is conducted to the surface of the wafer 3 through the coating needles 2, causing the metal ions in the ionic solution to be reduced to metal on the upper surface of the wafer 3, thereby forming a thin and solid metal coating on the upper surface of the wafer 3.

[0035] Please continue reading below. Figure 1 Step S102: A wafer is provided, and the coating equipment is used to coat the wafer. Please refer to the following section. Figure 2The wafer 3 is immersed in the ionic solution, and the coating needle 2 is brought into contact with the upper surface of the wafer 3. Current is conducted to the surface of the wafer 3 through the coating needle 2, forming a thin and solid coating on the surface of the wafer 3. In this embodiment, the ionic solution is a copper sulfate solution. The current is conducted to the surface of the wafer 3 through the coating needle 2, causing the copper ions in the ionic solution to be reduced to copper on the upper surface of the wafer 3, thereby forming a thin and solid metallic copper film on the upper surface of the wafer 3. In some embodiments, a copper rod is provided as the anode of the electrolysis, and the wafer serves as the cathode. The current ionizes the copper on the copper rod, that is, each copper atom loses electrons to become a positively charged copper ion. The reaction equation of the anode is as follows: Cu → Cu 2+ +2e - The positively charged copper ions dissolve in the ion solution of the coating cavity and flow to the surface of the wafer 3. The coating needle 2 contacts the surface of the wafer 3, causing the positively charged copper ions to gain electrons on the surface of the wafer 3 and be reduced to a metallic state, thereby forming a thin and solid metallic copper film on the wafer surface. The reaction equation of the cathode is as follows: Cu 2+ +2e - →Cu.

[0036] Please continue reading below. Figure 1 In step S103, during the coating process, the current in different areas on the surface of the wafer 3 is monitored. Figure 3 This is a schematic diagram of a method for improving wafer coating uniformity according to an embodiment of this disclosure. Please refer to the following. Figure 3 The monitoring of the current in different regions of the wafer surface includes: step S301, dividing the wafer surface into multiple regions; step S302, setting multiple data monitoring points in each region; and step S303, using the average current of the data monitoring points as the current of that region, so as to promptly detect uneven coating regions on the wafer surface during the coating process.

[0037] Please continue reading below. Figure 2 In this embodiment, the surface of the wafer 3 is divided into different regions A1 to A4, and multiple data monitoring points (not shown in the figure) are set in each region to monitor the current in regions A1 to A4 on the surface of the wafer 3. The average current of the data monitoring points is used as the current of the region to avoid data errors caused by a single data error.

[0038] Please continue reading below. Figure 1 In step S104, when the difference in current in different regions of the wafer surface is greater than a preset difference, the coating equipment is inspected.

[0039] Please continue reading below. Figure 2In this embodiment, the surface of wafer 3 is divided into different regions A1 to A4 to monitor the current in different regions of the wafer surface. The preset difference value can be determined based on the difference in current between different regions of the wafer surface during the previous wafer coating. For example, during the previous wafer coating, the current difference between regions A1 and A2, A1 and A3, and A1 and A4 is acquired and recorded as the current preset difference value between the current regions A1 and A2, A1 and A3, and A1 and A4 on the surface of wafer 3; the current difference between A2 and A3, and A2 and A4 is acquired as the current preset difference value between the current regions A2 and A3, and A2 and A4 on the surface of wafer 3; the current difference between A3 and A4 is acquired as the current preset difference value between the current regions A3 and A4 on the surface of wafer 3.

[0040] When the current difference between any two surface areas of wafer 3 during the current coating process is detected to be greater than a preset current difference between the two surface areas, the coating equipment is inspected. In this case, there may be metal residue on the surface of the coating equipment, requiring inspection. When the current difference between any two surface areas of wafer 3 during the current coating process is detected to be less than or equal to the preset current difference between the two surface areas, the next wafer is coated. In this case, there is no metal residue on the surface of the coating equipment, or the residue is very small and negligible, requiring no inspection. It is understood that the next wafer is coated only when the current difference between all paired surface areas is less than the preset current difference between them; if the current difference between any two surface areas is greater than the preset current difference, the coating equipment is inspected.

[0041] In the first embodiment, the surface of the wafer 3 is divided into different regions A1 to A4 to monitor the current in different regions of the wafer surface. In other embodiments, the method for improving the uniformity of wafer coating further includes: setting multiple concentric current loops on the coating equipment; when the difference in current between two current loops is greater than a preset difference, it is determined that the difference in current in different regions of the wafer surface is greater than the preset difference. Figure 4 This is a schematic diagram illustrating the division of the wafer surface region in the second embodiment of this disclosure. Please refer to the following: Figure 4 In the second embodiment, four concentric current loops 41-44 are provided on the coating equipment. In other embodiments, other numbers of current loops may also be provided. Multiple data monitoring points are set on the current loops, and the average current value of the data monitoring points is used as the current value of the current loop.

[0042] In this embodiment, four data monitoring points a1 to a4 are set on the current loop 41, and the average current of the data monitoring points a1 to a4 is used as the current value of the current loop 41; four data monitoring points b1 to b4 are set on the current loop 42, and the average current of the data monitoring points b1 to b4 is used as the current value of the current loop 42; four data monitoring points c1 to c4 are set on the current loop 43, and the average current of the data monitoring points c1 to a4 is used as the current value of the current loop 43; four data monitoring points d1 to d4 are set on the current loop 44, and the average current of the data monitoring points d1 to d4 is used as the current value of the current loop 44.

[0043] In some embodiments, the centers of the plurality of concentric current loops coincide with the center of the wafer 3, and the distances from the data monitoring points on the same current loop to the center of the wafer are equal, so as to improve the uniformity of data monitoring at the data monitoring points.

[0044] When the current difference between the two current loops is greater than a preset difference, it is determined that the current difference between different regions on the wafer surface is greater than the preset difference. The preset difference includes the current difference between the two current loops during the previous wafer coating. For example, the current difference between the annular regions between current loop 41 and current loop 42, current loop 41 and current loop 43, and current loop 41 and current loop 44 is acquired and recorded as the preset current difference between the annular regions between current loop 41 and current loop 42, current loop 41 and current loop 43, and current loop 41 and current loop 44 of the current wafer 3; the current difference between the annular regions between current loop 42 and current loop 43, and current loop 42 and current loop 44 of the current wafer 3 is acquired and recorded as the preset current difference between the annular regions between current loop 42 and current loop 43, and current loop 42 and current loop 44 of the current wafer 3; the current difference between the annular regions between current loop 43 and current loop 44 is acquired and recorded as the preset current difference between the annular regions between current loop 43 and current loop 44 of the current wafer 3.

[0045] When the current difference between any two current loops during the current coating process is detected to be greater than the preset current difference between those two current loops, the coating equipment is inspected. In this case, there may be metal residue on the surface of the coating equipment, requiring inspection. When the current difference between any two current loops during the current coating process is detected to be less than the preset current difference between those two current loops, the next wafer is coated. In this case, there is no metal residue on the surface of the coating equipment, or the residue is very small and negligible, requiring no inspection. It is understood that coating of the next wafer only occurs when the current difference between all paired current loops is less than the preset current difference between them; if the current difference between any two current loops is greater than the preset current difference, the coating equipment is inspected.

[0046] This embodiment accurately locates areas of uneven coating on the wafer by using the current difference between different current loops, quickly and accurately identifying the cause of coating equipment failure, facilitating timely adjustments to the coating process, improving coating uniformity, and increasing the yield of wafer coating.

[0047] In the second embodiment, when the current difference between any two current loops during the current coating process is detected to be less than a preset current difference between the two current loops, coating is performed on the next wafer without inspecting the coating equipment. However, due to limitations in process conditions and detection accuracy, this may lead to misjudgment. Therefore, to further improve the accuracy of monitoring, in some embodiments, the method further includes the following step: when the current in more than one of the current loops during the current coating process is detected to be greater than a preset standard current, the coating equipment is inspected. The preset standard current includes the current on the wafer surface during the previous wafer coating. For example, if the current in current loop 41 during the current wafer coating is greater than the current in current loop 41 on the wafer surface during the previous wafer coating, the coating equipment is inspected. When the current values ​​of all the current loops are less than or equal to the preset standard current, coating is performed on the next wafer.

[0048] The inspection of the coating equipment includes using a high-magnification microscope to inspect the components used in the coating process. For example, please refer to [link to relevant documentation]. Figure 1 Step S105: When it is found that there are deposits on the coating equipment, the coating equipment is cleaned.

[0049] Cleaning the coating equipment includes cleaning the coating needles. In some embodiments, the ionic solution is a copper sulfate solution. When forming a metallic copper film on the wafer surface, cleaning the coating needles includes cleaning the copper oxide and copper adhering to the coating needles. Figure 5This is a schematic diagram of a method for cleaning a coating needle according to an embodiment of the present disclosure. The cleaning of the coating needle includes: step S501, immersing the coating needle in an alkaline solution; step S502, rinsing the coating needle with clean water; step S503, immersing the coating needle in a mixture of an acidic solution and hydrogen peroxide for more than 30 minutes; and step S504, rinsing the coating needle with clean water.

[0050] In some embodiments, the alkaline solution is ammonia, the acidic solution is sulfuric acid, and the volume ratio of sulfuric acid, hydrogen peroxide, and water in the mixture of the acidic solution and hydrogen peroxide is (1-2):(2-4):(5-7).

[0051] In step S502, copper oxide is reduced to copper, wherein the reaction equation for copper oxide with ammonia is: 3CuO + 2NH3 = 3Cu + 3H2O + N2. In step S503, copper reacts with the acid washing solution and hydrogen peroxide in the mixed solution to generate copper sulfate, wherein the reaction equation for copper with the mixed solution is: Cu + H2SO4 + H2O2 = CuSO4 + 2H2O. The concentration of the ammonia is 10%–30%, the concentration of the sulfuric acid is 90%–99%, and the concentration of the hydrogen peroxide is 20%–40%.

[0052] The following comparison compares the results of immersing the coating needle in the mixed solution alone, immersing the coating needle in ammonia water alone, and immersing the coating needle in ammonia water and then immersing it in the mixed solution at a temperature of 20℃~25℃.

[0053] Figure 6 This is a graph showing the relationship between immersion time and number of cleaning cycles when only the mixed solution is used to clean the coating needle in one embodiment of this disclosure. The horizontal axis represents immersion time t, and the vertical axis represents the number of times the coating needle needs to be cleaned in 100 coating cycles, f. When only the mixed solution is used to immerse the coating needle, when the immersion time is 10-40 minutes, the number of times the coating needle needs to be cleaned in 100 coating cycles decreases as the immersion time increases; when the immersion time is greater than 40 minutes, the number of times the coating needle needs to be cleaned in 100 coating cycles does not change with the increase of immersion time, and the value stabilizes at 10 times.

[0054] Figure 7 This is a graph showing the relationship between immersion time and number of cleaning cycles when using only ammonia water to clean the coating needle in one embodiment of this disclosure. The horizontal axis represents immersion time t, and the vertical axis represents the number of times the coating needle needs to be cleaned in 100 coating cycles, f. When immersing the coating needle with only ammonia water, the number of times the coating needle needs to be cleaned in 100 coating cycles decreases as the immersion time increases when the immersion time is between 10 and 40 minutes. However, when the immersion time exceeds 40 minutes, the number of times the coating needle needs to be cleaned in 100 coating cycles does not change with the increase of immersion time and remains stable at 8 times.

[0055] Figure 8 This is a graph showing the relationship between soaking time and the number of cleaning cycles when cleaning the coating needle with ammonia water followed by a mixed solution in one embodiment of this disclosure. The horizontal axis represents the soaking time t, and the vertical axis represents the number of times the coating needle needs to be cleaned in 100 coating cycles, f. In this embodiment, the coating needle is soaked in ammonia water for 60 to 120 minutes, then cleaned with clean water, and then soaked in the mixed solution. When the soaking time is 10 to 50 minutes, the number of times the coating needle needs to be cleaned in 100 coating cycles decreases with increasing soaking time. When the soaking time is greater than 50 minutes, the number of times the coating needle needs to be cleaned in 100 coating cycles does not change with increasing soaking time and remains stable at 1.

[0056] The above comparison shows that soaking the coating needle in ammonia water and then soaking it in a mixed solution reduces the number of times the coating needle needs to be cleaned to once per 100 coating cycles, thus reducing the number of times the coating needle needs to be cleaned during the coating process and improving production efficiency.

[0057] The above technical solution, by monitoring the current in different areas of the wafer surface during the coating process, can promptly detect areas of uneven coating on the wafer surface. When the difference in current between different areas of the wafer surface exceeds a preset difference, the coating equipment is inspected to identify components requiring maintenance. When there are deposits on the coating equipment, it is cleaned with ammonia and a mixed solution to prevent the deposits from affecting the current conducted to the wafer surface and to improve the uniformity of the wafer coating.

[0058] Figure 9 This is a schematic diagram of a system for improving wafer coating uniformity according to an embodiment of this disclosure. Please refer to the following: Figure 9 The system for improving wafer coating uniformity includes: coating equipment U1; wafer (illustrated on...) Figure 2 The coating equipment is used to coat the wafer; the detection module U2 monitors the current in different areas of the wafer surface during the coating process; the judgment module U3 checks the coating equipment when the difference in current in different areas of the wafer surface is greater than a preset difference; and the cleaning module U4 cleans the coating equipment when there are deposits on it.

[0059] In some embodiments, the detection module U2 has multiple current detection devices for detecting current values ​​in different regions of the wafer surface, such as Hall effect sensors. The judgment module U3 includes a current comparison circuit that determines the relationship between the difference in current in different regions of the wafer surface and a preset difference. In some embodiments, the judgment module U3 further includes an amplification circuit that amplifies the current in different regions of the wafer surface so that the current comparison circuit can detect minute differences between the current difference in different regions of the wafer surface and the preset difference. The cleaning module U4 includes a cleaning device; in some embodiments, the cleaning module U4 further includes a drying device.

[0060] Figure 2 This is a schematic diagram of the coating apparatus according to the first embodiment of this disclosure. Please refer to the following: Figure 2 The coating equipment U1 includes a coating chamber 1 and multiple coating needles 2. The coating chamber 1 contains an ionic solution. The coating equipment is used to coat the wafer 3 by immersing the wafer 3 in the ionic solution, contacting the coating needles 2 with the upper surface of the wafer 3, and conducting current through the coating needles 2 to the surface of the wafer 3, causing the metal ions in the ionic solution to be reduced to metal on the upper surface of the wafer 3, thereby forming a thin and solid metal coating on the upper surface of the wafer 3.

[0061] Please refer to the following: Figure 9 The detection module U3 monitors the current in different areas on the surface of the wafer 3 during the coating process. Figure 3 This is a schematic diagram of a method for improving wafer coating uniformity according to an embodiment of this disclosure. Please refer to the following. Figure 3 The monitoring of the current in different regions of the wafer surface includes: step S301, dividing the wafer surface into multiple regions; step S302, setting multiple data monitoring points in each region; and step S303, using the average current of the data monitoring points as the current of that region, so as to promptly detect uneven coating regions on the wafer surface during the coating process.

[0062] Please refer to the following: Figure 9 The judgment module U3 checks the coating equipment when the current difference between different regions on the wafer surface is greater than a preset difference. When it detects that the current difference between any two surface regions of the wafer 3 during the current coating process is less than or equal to the preset current difference between the two surface regions, the next wafer is coated.

[0063] Please refer to the following: Figure 9The cleaning module U4 cleans the coating equipment when there are deposits on it. Inspecting the coating equipment includes examining the components used in the coating process using a high-powered microscope. For example, please refer to [link to relevant documentation]. Figure 1 Step S105: When it is found that there are deposits on the coating equipment, the coating equipment is cleaned.

[0064] Cleaning the coating equipment includes cleaning the coating needles. In some embodiments, the ionic solution is a copper sulfate solution. When forming a metallic copper film on the wafer surface, cleaning the coating needles includes cleaning the copper oxide and copper adhering to the coating needles. Figure 5 This is a schematic diagram of a method for cleaning a coating needle according to an embodiment of the present disclosure. The cleaning of the coating needle includes: step S501, immersing the coating needle in an alkaline solution; step S502, rinsing the coating needle with clean water; step S503, immersing the coating needle in a mixture of an acidic solution and hydrogen peroxide for more than 30 minutes; and step S504, rinsing the coating needle with clean water.

[0065] In some embodiments, the alkaline solution is ammonia, the acidic solution is sulfuric acid, and the volume ratio of sulfuric acid, hydrogen peroxide, and water in the mixture of the acidic solution and hydrogen peroxide is (1-2):(2-4):(5-7).

[0066] In step S502, copper oxide is reduced to copper, wherein the reaction equation for copper oxide with ammonia is: 3CuO + 2NH3 = 3Cu + 3H2O + N2. In step S503, copper reacts with the acid washing solution and hydrogen peroxide in the mixed solution to generate copper sulfate, wherein the reaction equation for copper with the mixed solution is: Cu + H2SO4 + H2O2 = CuSO4 + 2H2O. The concentration of the ammonia is 10%–30%, the concentration of the sulfuric acid is 90%–99%, and the concentration of the hydrogen peroxide is 20%–40%.

[0067] The following comparison compares the results of immersing the coating needle in the mixed solution alone, immersing the coating needle in ammonia water alone, and immersing the coating needle in ammonia water and then immersing it in the mixed solution at a temperature of 20℃~25℃.

[0068] Figure 6 This is a graph showing the relationship between soaking time and number of cleaning cycles when using only a mixed solution to clean the coating needle in one embodiment of this disclosure. Figure 7 This is a graph showing the relationship between soaking time and number of cleaning cycles when using only ammonia water to clean the coating needle in one embodiment of this disclosure. Figure 8This is a graph showing the relationship between immersion time and number of cleaning cycles when cleaning the coating needle with ammonia water followed by a mixed solution in one embodiment of this disclosure. The horizontal axis represents immersion time t, and the vertical axis represents the number of times the coating needle needs to be cleaned out of 100 coating cycles, f.

[0069] When the coating needle is immersed in the mixed solution for 10 to 40 minutes, the number of times the coating needle needs to be cleaned per 100 coatings decreases as the immersion time increases. However, when the immersion time exceeds 40 minutes, the number of times the coating needle needs to be cleaned per 100 coatings remains unchanged as the immersion time increases, and the value stabilizes at 10 times.

[0070] The above comparison shows that soaking the coating needle in ammonia water and then soaking it in a mixed solution reduces the number of times the coating needle needs to be cleaned to once per 100 coating cycles, thus reducing the number of times the coating needle needs to be cleaned during the coating process and improving production efficiency.

[0071] The above technical solution uses coating equipment U1 to coat wafer 3. Monitoring module U2 monitors the current in different areas of the wafer surface, enabling timely detection of areas with uneven coating during the coating process. When the difference in current between different areas of the wafer surface exceeds a preset value, the coating equipment is inspected, and judgment module U3 identifies components requiring maintenance. When there are deposits on the coating equipment, cleaning module U4 cleans the equipment with ammonia and a mixed solution to prevent these deposits from affecting the current conducted to the wafer surface and improving the uniformity of the wafer coating.

[0072] The above description is only a preferred embodiment of this application. It should be noted that those skilled in the art can make several improvements and modifications without departing from the principle of this invention, and these improvements and modifications should also be considered within the scope of protection of this invention.

Claims

1. A method for improving the uniformity of wafer coating, characterized in that, include: Provide coating equipment; A wafer is provided, and the coating equipment is used to coat the wafer; During the coating process, the current in different areas of the wafer surface is monitored; When the difference in current in different regions of the wafer surface is greater than a preset difference, the coating equipment is inspected. When there are deposits on the coating equipment, the coating equipment should be cleaned. Cleaning the coating equipment includes cleaning the coating needles; Cleaning the coating needle includes: The coating needle was immersed in an alkaline solution. Clean the coating needle with clean water; The coating needle is immersed in a mixture of acidic solution and hydrogen peroxide for more than 30 minutes. Clean the coating needle with clean water; The alkaline solution is ammonia water with a concentration of 10% to 30%, and the acidic solution is sulfuric acid.

2. The method for improving wafer coating uniformity according to claim 1, characterized in that, Also includes: Multiple concentric current loops are arranged on the coating equipment; When the difference in current between two current loops is greater than a preset difference, it is determined that the difference in current in different regions of the wafer surface is greater than the preset difference.

3. The method for improving wafer coating uniformity according to claim 2, characterized in that, The preset difference includes the difference in current between the two current loops during the previous wafer coating.

4. The method for improving wafer coating uniformity according to claim 2, characterized in that, Also includes: When the current in one or more of the current loops exceeds the preset standard current, the coating equipment is inspected.

5. The method for improving wafer coating uniformity according to claim 4, characterized in that, The preset standard current includes the current on the wafer surface during the previous wafer coating process.

6. The method for improving wafer coating uniformity according to claim 2, characterized in that, Also includes: Multiple data monitoring points are set on the current loop, and the average current of the data monitoring points is used as the current value of the current loop.

7. The method for improving wafer coating uniformity according to claim 1, characterized in that, The monitoring of current in different regions of the wafer surface includes: The wafer surface is divided into multiple regions; Multiple data monitoring points are set up in each of the aforementioned areas; The average current at the data monitoring points is used as the current in that area.

8. The method for improving wafer coating uniformity according to claim 1, characterized in that, Also includes: When the difference in current in different regions of the wafer surface is less than or equal to a preset difference, the next wafer is coated.

9. The method for improving wafer coating uniformity according to claim 1, characterized in that, Also includes: The parts used for coating were inspected using a high-powered microscope.

10. The method for improving wafer coating uniformity according to claim 1, characterized in that, The volume ratio of sulfuric acid, hydrogen peroxide, and water in the mixture is (1~2):(2~4):(5~7), the concentration of sulfuric acid is 90%~99%, and the concentration of hydrogen peroxide is 20%~40%.

11. A system for improving the uniformity of wafer coating, characterized in that, include: Coating equipment; Wafer, the coating equipment being used to coat the wafer; The detection module monitors the current in different areas of the wafer surface during the coating process; The judgment module checks the coating equipment when the difference in current in different areas of the wafer surface is greater than a preset difference. The cleaning module cleans the coating equipment when there are deposits on it, including cleaning the coating needles. Cleaning the coating needle includes: The coating needle was immersed in an alkaline solution. Clean the coating needle with clean water; The coating needle is immersed in a mixture of acidic solution and hydrogen peroxide for more than 30 minutes. Clean the coating needle with clean water; The alkaline solution is ammonia water with a concentration of 10% to 30%, and the acidic solution is sulfuric acid.

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