A photoresist coating method for improving uniformity

Abstract

This invention proposes a method to improve the uniformity of photoresist coating on wafers. During photoresist coating, the application time at 1500-3500 rpm / min should be less than the total application time of the photoresist pump (the time ratio is adjusted experimentally based on different viscosities, accounting for 85%-95% of the application time; the application time is appropriately reduced as the photoresist viscosity increases). This leaves some time for the next step of applying the photoresist, followed by rotation at 1000-3500 rpm / min for a certain period to form a film. This improves the uniformity of the photoresist film thickness.

Description

Technical Field

[0001] This invention belongs to the field of photolithography technology in the integrated circuit manufacturing industry, and relates to wafer coating and developing equipment, providing a method for improving the uniformity of photoresist coating on wafers. Background Technology

[0002] Wafer coating and developing equipment is an automated wafer processing device in the semiconductor manufacturing industry, and one of the core pieces of equipment in the photolithography process. It contains modules for coating, developing, bonding, and baking, with the coating module being the most crucial unit. In chip manufacturing, after passing through the coating unit, a layer of photoresist is uniformly coated onto the wafer surface. The thickness and uniformity of this photoresist coating directly affect the stability of the linewidth during subsequent exposures, thus impacting product yield. With technological advancements, the linewidth of semiconductor devices continues to shrink, increasing the demands on the uniformity of photoresist coating. Therefore, improving the process performance of the coating unit has become a critical standard for major chip manufacturers.

[0003] There are many forms of uneven photoresist coating on wafer surfaces. One common issue is that the photoresist thickness is similar in the central and edge regions of the wafer, but thinner at half the wafer radius. This results in a large thickness difference (the difference between the maximum and minimum thickness measured in film thickness measurements) and poor uniformity, affecting the linewidth uniformity during development. Uniformity is usually the most difficult to adjust, and conventional coating formulations offer limited improvement for this type of coating. Summary of the Invention

[0004] This invention proposes a novel coating method that can effectively improve coating uniformity, reduce the thickness difference range, and improve the uniformity of photoresist film thickness.

[0005] A method for improving the uniformity of photoresist coating on a wafer, wherein the photoresist spin coating process includes either process A or B below:

[0006] A. Applying glue (or spraying glue) using the nozzle, total time is X.

[0007] 1) When the nozzle starts applying the photoresist (time is 0), the wafer rotates at 1500-3500 rpm / min (the speed varies depending on the viscosity and properties of the photoresist, but this range is generally covered; preferably 1800-2800 rpm) until 85%-95% (preferably 87-93%, more preferably 89%-91%) of the total photoresist application time X (this process takes place from 0 to (85%-95%)X, preferably (87-93%)X, more preferably (89%-91%)X, and time is measured as K).

[0008] 2) When the wafer is rotated at a speed of 50-300 rpm / min (this speed range is basically covered, preferably 100-200 rpm), and the total glue application time is X + (0.1-3) s (preferably X + (0.1-2) s, more preferably X + (0.1-1.5) s), the time interval is from K to X + (0.1-3) s (preferably from K to X + (0.1-2) s, more preferably from K to X + (0.1-1.5) s).

[0009] 3) Then the wafer is rotated at a speed of 1000-3500 rpm / min (preferably 1200-2500, more preferably 1500-2000) to form a film;

[0010] Alternatively, option B involves applying glue (or spraying glue) using a glue nozzle, with a total time of Y.

[0011] 1) When the nozzle starts applying glue (at which time the timer is 0), the wafer first rotates at a speed of 0-500 rpm / min (preferably 0-300, more preferably 0-200) (stationary or rotating) until 20%-50% (preferably 25%-45%, more preferably 30%-40%) of the total glue application time Y (at which time the time interval is 0 to (20%-50%)Y, preferably to 0 to (25%-45%)Y, more preferably to 0 to (30%-40%)Y, at which time the timer is Z);

[0012] 2) Then the wafer is rotated at 1500-3500 rpm / min (preferably 1800-2800 rpm / min, more preferably 2000-2600 rpm / min) to 85%-95% (preferably 87-93%, more preferably 89%-91%) of the coating time YZ. At this time, the time period is Z to Z + (85%-95%) multiplied by (YZ) (preferably Z + (87%-93%) multiplied by (YZ), more preferably Z + (89%-91%) multiplied by (YZ)).

[0013] 3) The wafer is then rotated at a speed of 50-300 rpm / min (preferably 80-250, more preferably 100-200) until the total glue application time of the nozzle is Y+(0.1-3)s (preferably to Y+(0.1-2)s, more preferably to Y+(0.1-1.5)s). At this time, the time period is Z+(85%-95%) multiplied by (YZ) (preferably Z+(87%-93%) multiplied by (YZ), more preferably Z+(89%-91%) multiplied by (YZ)) to Y+(0.1-3)s (preferably to Y+(0.1-2)s, more preferably to Y+(0.1-1.5)s);

[0014] 4) The wafer is then rotated at a speed of 1000-3500 rpm / min (preferably 1200-2500, more preferably 1500-2000) to form a film.

[0015] The total dispensing time X and Y are independently determined by the dispensing volume and dispensing rate settings of the photoresist pump. Different dispensing rates are set according to different photoresist viscosities. The total time X and Y are equal to the dispensing volume / dispensing rate, which is usually 2-8 (seconds), preferably 3-7s, and more preferably 4-5s.

[0016] The dispensing rate of the nozzle is 0.5-2 ml / s, preferably 0.7-1.5, and more preferably 0.8-1.2.

[0017] The wafer is then rotated at a speed of 1000-3500 rpm / min (preferably 1200-2500, more preferably 1500-2000) for 20-50 seconds, preferably 25-40 seconds, more preferably 30-40 seconds.

[0018] The viscosity of the photoresist is tested in the range of 5-100 CP (or cP s, centipoise), preferably 20-80 CP, and more preferably 30-70 CP.

[0019] Silicon wafers with a diameter of 200-300mm.

[0020] The specific steps for applying photoresist to the wafer surface using this method are as follows:

[0021] (1) The wafer is vacuum-adsorbed onto the wafer stage, with the upper surface of the wafer parallel to the horizontal plane;

[0022] (2) The photoresist thinner nozzle dispenses liquid at the very center of the wafer, with the nozzle at a vertical distance of 5-6 mm from the wafer surface. At this time, the wafer rotates at a speed of 0-30 rpm / min (preferably 0-25, more preferably 0-20) and then spreads out at a speed of 800-2000 rpm / min (preferably 800-1500, more preferably 800-1200) for a time of 0.1-3 s (preferably 0.1-2 s, more preferably 1.0-1 s).

[0023] (3) The photoresist nozzle starts applying the photoresist directly above the center of the wafer (directly above the center of the upper surface). The vertical distance between the lower exit end of the nozzle and the wafer surface is 5-6 mm. The photoresist application rate is 0.5-2 ml / s (preferably 0.7-1.5, more preferably 0.8-1.2).

[0024] (4) The wafer is rotated at a speed of 1000-3500 rpm / min for a certain period of time to form a film of photoresist on the wafer surface.

[0025] In step 2), the photoresist diluent dispensing time is 2-6s (preferably 2-5s, more preferably 3-4s), and the dispensing rate is 70-80 ml / min (preferably 75 ml / min, more preferably 80 ml).

[0026] The specific steps for applying photoresist to the wafer surface using this method are as follows:

[0027] (1) The wafer is vacuum adsorbed on the wafer stage. After vacuum adsorption, the wafer (the upper surface of the wafer is parallel to the horizontal plane) can rotate together with the wafer stage. The wafer diameter is 200-300mm silicon wafer.

[0028] (2) The photoresist thinner nozzle dispenses the thinner at the exact center of the wafer, with the nozzle 5-6 mm vertically from the wafer surface. At this point, the wafer rotates at a speed of 0-30 rpm / min, and then spreads out at a speed of 800-2000 rpm / min for 0.1-3 seconds.

[0029] (3) The photoresist nozzle begins applying the photoresist directly above the center of the wafer (directly above the center of the upper surface). The vertical distance between the lower exit end of the nozzle and the wafer surface is 5-6 mm, and the application rate is 0.5-2 ml / s. At this time, the wafer rotates at a speed of 1500-3500 rpm / min. Figure 1 This step should take less than the total photoresist application time (accounting for 85%-95% of the total photoresist application time). Afterwards, rotate the wafer at a speed of 50-300 rpm / min for 1-3 seconds. At this speed, because the photoresist application is not yet complete, some photoresist will still remain at the center of the wafer. Figure 2 The presence of this photoresist can effectively improve the uniformity of the coating.

[0030] (4) The wafer is rotated at a speed of 1000-3500 rpm / min for a certain period of time to allow the photoresist to form a film on the wafer surface. This step can control the overall thickness of the film layer.

[0031] The photoresist viscosity is tested within the range of 5-100 CP (cPs, centipoise); the testing temperature is 22-23℃. The advantages and beneficial effects of this invention are:

[0032] 1. This invention does not change the original equipment structure, but only improves the process results by adjusting the process formula, thus saving equipment modification costs.

[0033] This invention proposes a novel photoresist coating method that can improve the situation where the photoresist thickness is too thin at 1 / 2 of the wafer radius, thereby reducing the thickness difference range and effectively improving the uniformity of the coating.

[0034] 2. When applying the photoresist, the viscosity of the photoresist can be used in the range of 5-100 CP, which can be applied to most photoresists.

[0035] 3. This invention has played a crucial role in improving the level of photolithography technology in the integrated circuit manufacturing industry. Attached Figure Description

[0036] Figure 1 This is a schematic diagram of the wafer coating process; ①. Photoresist nozzle, ②. Wafer, ③. Photoresist, ④. Wafer stage;

[0037] Figure 2 This is a schematic diagram of the adhesive application process after formula improvement;

[0038] Figure 3-1 This is a comparison chart of photoresist coating effect data for Example 1 (comparison group); under the original formulation, the photoresist thickness in the central and edge areas is similar, while the photoresist thickness is thinner at 1 / 2 of the wafer radius; the horizontal and vertical axes in the figure represent the measurement points (49 points in total) and the photoresist thickness, respectively.

[0039] Figure 3-2 The image shows the photoresist coating effect data for Example 1 (from the present invention group); the horizontal and vertical axes in the image represent the measurement points, totaling 49 points, and the photoresist thickness, respectively.

[0040] Figure 4 The diagram shows the measurement points of 49 points after coating in the embodiments and comparative examples of this invention. 25 points were measured horizontally and 24 points were measured vertically, for a total of 49 points of film thickness data (49 points of film thickness data were measured and a profile was drawn).

[0041] Figure 5-1 This is a comparison chart of the photoresist coating effect data in Example 2 (comparison group); the horizontal and vertical axes in the chart represent the measurement points, a total of 49 points, and the photoresist thickness, respectively.

[0042] Figure 5-2 The image shows the photoresist coating effect data for Example 2 (from the present invention group); the horizontal and vertical axes in the image represent the measurement points (49 points in total) and the photoresist thickness, respectively.

[0043] Figure 6 This is a data graph showing the adhesive application effect in Comparative Example 1;

[0044] Figure 7 This is a data graph showing the adhesive application effect in Comparative Example 2. Detailed Implementation

[0045] Example 1

[0046] Manufacturer: Sumitomo Chemical Co., Ltd., Model: PFI89B8 (32CP) Photoresist Coating Uniformity Improvement under Original Process Conditions (Control Group):

[0047] (1) The wafer is vacuum adsorbed on the wafer stage. After vacuum adsorption, the wafer (the upper surface of the wafer is parallel to the horizontal plane) can rotate together with the wafer stage. The wafer diameter is 200mm silicon wafer.

[0048] (2) Photoresist thinner (Anzhi Electronic Materials Co., Ltd.: AZ7030) is dispensed from the center of the wafer (directly above the center of the upper surface). The vertical distance between the lower outlet of the nozzle and the wafer surface is 5 mm. The dispensing time is 2 seconds and the dispensing rate is 75 ml / min. At this time, the wafer rotates at a speed of 30 rpm / min. After dispensing, it spreads out at a speed of 2000 rpm / min for 0.1 seconds.

[0049] (3) Photoresist (Sumitomo, PFI89B8; viscosity 32CP, measurement temperature 22℃) The nozzle is directly above the center of the wafer (the center of the upper surface of the wafer). The vertical distance between the lower exit end of the nozzle and the wafer surface is 5mm. The nozzle dispensing rate is 1 ml / s, the dispensing time of the dispensing pump is 3s, and the dispensing volume is 3ml. At this time, the wafer rotates at a speed of 3250rpm / min. This step takes 3s. After that, the wafer is rotated at a speed of 3s and 100rpm / min.

[0050] (4) The wafer is rotated at a speed of 2000 rpm / min for 30 seconds to allow the photoresist to form a film on the wafer surface. This step can control the overall thickness of the film and the average mean value of the film thickness, as shown in Table 1.

[0051] Under the process conditions of this invention (the present invention group):

[0052] (1) The wafer is vacuum adsorbed on the wafer stage. After vacuum adsorption, the wafer (the upper surface of the wafer is parallel to the horizontal plane) can rotate together with the wafer stage. The wafer diameter is 200mm silicon wafer.

[0053] (2) Photoresist thinner (Anzhi Electronic Materials Co., Ltd., AZ7030) is dispensed from the center of the wafer (directly above the center of the upper surface). The vertical distance between the lower outlet of the nozzle and the wafer surface is 5 mm. The dispensing time is 2 s and the dispensing rate is 75 ml / min. At this time, the wafer rotates at a speed of 30 rpm / min. After dispensing, it is spread out at a speed of 2000 rpm / min for 0.1 s.

[0054] (3) Photoresist (Sumitomo Chemical Co., Ltd., PFI89B8; viscosity 32CP, measurement temperature 22℃) The nozzle starts applying photoresist directly above the center of the wafer (the center of the upper surface of the wafer). The vertical distance between the lower exit end of the nozzle and the wafer surface is 5mm. The nozzle application rate is 1 ml / s, the application time of the photoresist pump is 3s, and the application volume is 3ml. At this time, the wafer rotates at a speed of 3250rpm / min, and this step takes 2.7s. After that, the wafer is rotated at a time of 3s and a speed of 100rpm / min. At this speed, since there is still 0.3s of application time left, the nozzle still applies photoresist to the center of the wafer for 0.3s. At this time, there is still some photoresist in the center of the wafer. The presence of this part of the photoresist can effectively improve the uniformity of the coating.

[0055] (4) The wafer is rotated at a speed of 2000 rpm / min for 30 seconds to allow the photoresist to form a film on the wafer surface. This step can control the overall thickness of the film and the average mean value of the film thickness, as shown in Table 1.

[0056] Comparison of adhesive application effect data is shown in Table 1 and Figure 3-1 , 3-2 As shown in Figure 4:

[0057] Table 1: Uniformity improvement effect before optimization (comparison group) and after optimization (invention group).

[0058]

[0059] The table shows the meaning and calculation process of the values. The data in the table is as follows:

[0060] The mean value is the average of the 49 measured data points.

[0061] The min value is the minimum value of the 49 measured data points;

[0062] The maximum value is the maximum value of the 49 measured data points.

[0063] range is the maximum value minus the minimum value of the 49 measured data points. The smaller the value, the better the uniformity.

[0064] STD is the standard deviation of 49 measurement points, which characterizes the uniformity of film thickness. The smaller the value, the better the uniformity.

[0065] From Table 1 and Figure 3-1 , 3-2 It can be seen that by using the recipe of this invention, the range of film thickness data is optimized from 450-550A to 130-180A, and the profile is flatter.

[0066] Example 2

[0067] TOK (Tokyo Ohka Kogyo Co., Ltd.), IP5800 (68CP) photoresist coating uniformity improvement under original process conditions (control group):

[0068] (1) The wafer is vacuum adsorbed on the wafer stage. After vacuum adsorption, the wafer (the upper surface of the wafer is parallel to the horizontal plane) can rotate together with the wafer stage. The wafer diameter is 300mm silicon wafer.

[0069] (2) Photoresist thinner (Anzhi Electronic Materials Co., Ltd., AZ7030) is dispensed from the center of the wafer (directly above the center of the upper surface). The vertical distance between the lower outlet of the nozzle and the wafer surface is 6 mm. The dispensing time is 5 s and the dispensing rate is 75 ml / min. At this time, the wafer rotates at a speed of 30 rpm / min. After dispensing, it spreads out at a speed of 1860 rpm / min for 3 s.

[0070] (3) Photoresist (Tokyo Ohka Kogyo Co., Ltd., IP5800; viscosity 68cp, measurement temperature 22℃) The nozzle is positioned directly above the center of the wafer (the center of the upper surface of the wafer) to begin applying the photoresist. The vertical distance between the lower exit end of the nozzle and the wafer surface is 6mm. The nozzle application rate is 0.8 ml / s, the application time of the photoresist pump is 7.5s, and the application volume is 6ml. At this time, the wafer is first applied statically at a speed of 0 rpm / min for 3.5s, and then rotated at a speed of 2200 rpm / min for 4s. After that, it is rotated at a speed of 50 rpm / min for 2s.

[0071] (4) The wafer is rotated at a speed of 1832 rpm / min for 45 seconds to allow the photoresist to be deposited on the wafer surface. This step can control the overall thickness of the film and the average mean value of the film thickness, as shown in Table 2.

[0072] Under the process conditions of this invention (the present invention group):

[0073] (1) The wafer is vacuum adsorbed on the wafer stage. After vacuum adsorption, the wafer (the upper surface of the wafer is parallel to the horizontal plane) can rotate together with the wafer stage. The wafer diameter is 300mm silicon wafer.

[0074] (2) Photoresist thinner (Anzhi Electronic Materials Co., Ltd., AZ7030) is dispensed from the center of the wafer (directly above the center of the upper surface). The vertical distance between the lower outlet of the nozzle and the wafer surface is 6 mm. The dispensing time is 5 s and the dispensing rate is 75 ml / min. At this time, the wafer rotates at a speed of 30 rpm / min. After dispensing, it is spread out at a speed of 2000 rpm / min for 3 s.

[0075] (3) Photoresist (Tokyo Ohka Kogyo Co., Ltd., IP5800; viscosity 68cp, measurement temperature 22℃) The nozzle starts applying photoresist directly above the center of the wafer (the center of the upper surface of the wafer). The vertical distance between the lower exit end of the nozzle and the wafer surface is 6mm. The nozzle application rate is 0.8 ml / s, the dispensing time of the dispensing pump is 7.5s, and the dispensing volume is 6ml. At this time, the wafer is first stationary at a speed of 0 rpm / min for 3.5s, and then rotated at a speed of 2200 rpm / min for 3.3s. After that, it is rotated at a time of 2s and a speed of 50 rpm / min. At this speed, since there is still 0.7s of dispensing time left, the nozzle still applies photoresist to the center of the wafer for 0.7s. At this time, there is still some photoresist in the center of the wafer. The presence of this part of photoresist can effectively improve the uniformity of the coating.

[0076] (4) The wafer is rotated at a speed of 1832 rpm / min for 45 seconds to allow the photoresist to be deposited on the wafer surface. This step can control the overall thickness of the film and the average mean value of the film thickness, as shown in Table 2.

[0077] Comparison of adhesive application effect data is shown in Table 2 and Figure 5-1 , 5-2 As shown in Figure 4:

[0078] Table 2: Uniformity improvement effect before optimization (comparison group) and after optimization (invention group).

[0079]

[0080] The table shows the meaning and calculation process of the values. The data in the table is as follows:

[0081] The mean value is the average of the 49 measured data points.

[0082] The min value is the minimum value of the 49 measured data points;

[0083] The maximum value is the maximum value of the 49 measured data points.

[0084] range is the maximum value minus the minimum value of the 49 measured data points. The smaller the value, the better the uniformity.

[0085] STD is the standard deviation of 49 measurement points, which characterizes the uniformity of film thickness. The smaller the value, the better the uniformity.

[0086] From Table 2 and Figure 5-1 , 5-2 It can be seen that by using the recipe of this invention, the range of film thickness data is optimized from 450-550A to 130-180A, and the profile is flatter.

[0087] Comparative Example 1

[0088] (1) The wafer is vacuum adsorbed on the wafer stage. After vacuum adsorption, the wafer (the upper surface of the wafer is parallel to the horizontal plane) can rotate together with the wafer stage. The wafer diameter is 300mm silicon wafer.

[0089] (2) Photoresist thinner (Anzhi Electronic Materials Co., Ltd., AZ7030) is dispensed from the center of the wafer (directly above the center of the upper surface). The vertical distance between the lower outlet of the nozzle and the wafer surface is 6 mm. The dispensing time is 5 s and the dispensing rate is 75 ml / min. At this time, the wafer rotates at a speed of 30 rpm / min. After dispensing, it is spread out at a speed of 2000 rpm / min for 3 s.

[0090] (3) Photoresist (Tokyo Ohka Kogyo Co., Ltd. IP5800; viscosity 68cp, measurement temperature 22℃) The nozzle starts applying photoresist directly above the center of the wafer (the center of the upper surface of the wafer). The vertical distance between the lower exit end of the nozzle and the wafer surface is 6mm. The nozzle application rate is 0.8 ml / s, the dispensing time of the dispensing pump is 7.5s, and the dispensing volume is 6ml. At this time, the wafer is first stationary at a speed of 0 rpm / min for 3.5s, and then rotated at a speed of 2200 rpm / min for 2.4s. After that, it is rotated at a time of 2s and a speed of 50 rpm / min. At this speed, since there is still 1.6s of dispensing time left, the nozzle is still applying photoresist to the center of the wafer for 1.6s. At this time, there is still some photoresist in the center of the wafer.

[0091] (4) The wafer is rotated at a speed of 1832 rpm / min for 45 seconds to allow the photoresist to be deposited on the wafer surface. This step can control the overall thickness of the film and the average value of the mean film thickness, as shown in Table 3.

[0092] Comparison of adhesive application effect data is shown in Table 3 and Figure 6 , 4 As shown:

[0093] The original process is the comparison group of Example 2: Table 3: Uniformity effect

[0094] Comparative Example 2

[0095] (1) The wafer is vacuum adsorbed on the wafer stage. After vacuum adsorption, the wafer (the upper surface of the wafer is parallel to the horizontal plane) can rotate together with the wafer stage. The wafer diameter is 300mm silicon wafer.

[0096] (2) Photoresist thinner (Anzhi Electronic Materials Co., Ltd., AZ7030) is dispensed from the center of the wafer (directly above the center of the upper surface). The vertical distance between the lower outlet of the nozzle and the wafer surface is 6 mm. The dispensing time is 5 s and the dispensing rate is 75 ml / min. At this time, the wafer rotates at a speed of 30 rpm / min. After dispensing, it is spread out at a speed of 2000 rpm / min for 3 s.

[0097] (3) Photoresist (Tokyo Ohka Kogyo Co., Ltd., IP5800; viscosity 68cp, measurement temperature 22℃) The nozzle starts applying photoresist directly above the center of the wafer (the center of the upper surface of the wafer). The vertical distance between the lower exit end of the nozzle and the wafer surface is 6mm. The nozzle application rate is 0.8 ml / s, the dispensing time of the dispensing pump is 7.5s, and the dispensing volume is 6ml. At this time, the wafer is first stationary at a speed of 0 rpm / min for 3.5s, and then rotated at a speed of 2200 rpm / min for 3.9s. After that, it is rotated at a time of 2s and a speed of 50 rpm / min. At this speed, since there is still 0.1s of dispensing time left, the nozzle is still applying photoresist to the center of the wafer for 0.1s. At this time, there is still some photoresist in the center of the wafer.

[0098] (4) The wafer is rotated at a speed of 1832 rpm / min for 45 seconds to allow the photoresist to form a film on the wafer surface. This step can control the overall thickness of the film and the average mean value of the film thickness, as shown in Table 4.

[0099] Comparison of adhesive application effect data is shown in Table 4 and Figure 7 , 4 As shown:

[0100] Example 2 Comparative Group, Table 4: Uniformity Effect

[0101]

[0102] The data shows that the remaining photoresist time is too short in the 50-300 rpm / min step, resulting in poor process quality. Due to the short remaining photoresist time at low speeds, there is insufficient remaining photoresist. Under long-term high speeds, the photoresist still cannot fill to 1 / 2 of the wafer radius, resulting in increased thickness in the central area and poor uniformity.

Claims

1. A method for improving the uniformity of photoresist coating on a wafer, characterized in that, Includes the following steps: (1) The wafer is vacuum-adsorbed onto the substrate; (2) The photoresist diluent is discharged from the center of the wafer for 2 to 6 seconds at a rate of 70 to 80 ml / min. At the same time, the wafer is rotated at 0 to 30 rpm and then spread out at 800 to 2000 rpm for 0.1 to 3 seconds. (3) The photoresist nozzle starts applying the photoresist directly above the center of the wafer. The total amount of photoresist applied is 3 ml, and the application rate is 0.5~2 ml / second. The total application time is X. (4) After the glue application begins, the wafer is rotated at 1500~3500 rpm, and the glue application time is 85%~95% of the total glue application time; The wafer is then rotated at 50~300 rpm and the adhesive is applied until the application is complete. The rotation continues until the total adhesive application time is X + (0.1-3) s. The wafer is rotated at 1000~3500 rpm for 20~50 seconds to form a photoresist film on the wafer surface.

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