Photoresist coating method

Abstract

The application belongs to the technical field of semiconductor integrated circuits, and particularly relates to a photoresist coating method. The photoresist coating method comprises the following steps: dropping a first liquid on a first surface of a wafer, driving the wafer to rotate so that the first liquid moves from a dropping point to an edge of the wafer, and removing particles on the first surface of the wafer; after spraying an adhesive on the first surface of the wafer, dropping the first liquid on the first surface of the wafer again, driving the wafer to rotate so that the first liquid moves from the dropping point to the edge of the wafer, and making the gaseous mist-like adhesive adsorbed on the surface of the wafer evenly spread on the first surface of the wafer through the movement of the first liquid; and finally, dropping photoresist on the center of the wafer, and driving the wafer to rotate so that the photoresist is evenly coated on the first surface of the wafer. The photoresist coating method of the application can spin-coat ultra-thin and high-uniformity photoresist on the surface of the wafer.

Description

Technical Field

[0001] This application relates to the fields of semiconductor integrated circuits and advanced packaging technology, and specifically to a photoresist coating method. Background Technology

[0002] Photoresist coating, also known as homogenization or photoresist application, involves creating a thin, uniform, and defect-free photoresist film on the surface of a wafer. Within the ultra-thin thickness range of 100nm for the target photoresist, non-uniformity is typically between 3% and 5%. Before the photoresist coating process, microparticles, invisible to the naked eye, adhere to the photoresist surface. However, in the coating process of ultra-thin photoresist films, these microparticles can significantly affect the coating effect. In addition, the traditional two-stage coating method is generally used for photoresist coating on wafers. The two-stage coating will result in the thickness of the wafer in the middle being higher than that at the edges. This is because the two-stage coating is different from the one-stage coating method. The two-stage coating is a second coating on the previous coating film. The second coating film will undergo a second physical interaction with the first coating film. Especially at the center of the die, the coating liquid in the center of the wafer has the longest fusion time with the previous coating film. This results in the solvent being consumed faster in the middle and slower at the edges, forming a concentration gradient difference in the coating liquid. As a result, the coating in the middle is significantly thicker than that at the edges. After curing, wrinkles will appear in the photoresist at the edges. Summary of the Invention

[0003] This application provides a photoresist coating method that can solve problems such as low uniformity of ultrathin photoresists, low spin coating efficiency, and low process yield.

[0004] The photoresist coating method provided in this application embodiment is used to coat photoresist on the surface of a wafer, and the method includes the following steps:

[0005] S1. A first liquid is dropped onto the first surface of the wafer to pre-wet the wafer. The pre-wetting includes a first pre-wetting stage and a second pre-wetting stage performed sequentially.

[0006] In the first stage of pre-rinsing, a predetermined amount of first liquid is dropped onto the first surface of the wafer, driving the wafer to rotate with a first acceleration.

[0007] In the second stage of pre-rinsing, a second predetermined amount of the first liquid is dropped onto the first surface of the wafer. First, the acceleration of the wafer is increased instantaneously so that the rotation speed of the wafer reaches the first predetermined speed. Then, the wafer is driven to rotate at a constant speed at the first predetermined speed, which is greater than the maximum rotation speed of the wafer in the first stage of pre-rinsing.

[0008] S2. Spray an adhesive to improve the adhesion of the photoresist onto the first surface of the wafer;

[0009] S3. A third predetermined amount of first liquid is dropped onto the first surface of the wafer, and the wafer is driven to rotate so that the first liquid moves from the dropping point toward the edge of the wafer, so that the adhesive is evenly spread on the first surface of the wafer through the movement of the first liquid.

[0010] S4. Drop a fourth predetermined amount of photoresist onto the center of the wafer, and drive the wafer to rotate so that the fourth predetermined amount of photoresist is uniformly coated on the first surface of the wafer.

[0011] Steps S1, S3, and S4 are all performed within the coating unit cavity used for coating the wafer.

[0012] According to the foregoing embodiments of this application, step S4 includes the following steps:

[0013] S41. A fourth predetermined amount of photoresist is dropped onto the center of the wafer. During the first time period after the dropping is completed, the wafer is driven to rotate with a second acceleration so that the fourth predetermined amount of photoresist is spread on the first surface.

[0014] S42. During a second time period following the first time period, the wafer is driven to rotate at a second predetermined speed to form a photoresist coating of uniform thickness on the first surface of the wafer; wherein the first time period is shorter than the second time period.

[0015] According to any of the foregoing embodiments of this application, step S2 includes:

[0016] The wafer is fed into the binder unit cavity, and the vapor-phase binder is sprayed onto the first surface of the wafer.

[0017] The temperature inside the adhesive unit cavity is greater than or equal to 90℃.

[0018] According to any of the foregoing embodiments of this application, after step S2, the following is included:

[0019] The wafer is fed into the cooling chamber, and the temperature of the cooling chamber is reduced to 20℃~30℃.

[0020] According to any of the foregoing embodiments of this application, step S3 includes

[0021] A third predetermined amount of the first liquid is dropped onto the first surface of the wafer to increase the acceleration of the wafer so that the wafer reaches a third predetermined rotational speed;

[0022] The wafer is driven to rotate at a third predetermined speed at a constant speed for a period of less than 20 seconds.

[0023] According to any of the foregoing embodiments of this application, the time for spraying the adhesive on the first surface of the wafer is less than or equal to 40 seconds.

[0024] According to any of the foregoing embodiments of this application, the first time period is less than or equal to 5 seconds, and the second acceleration gradually increases from the initial value to the maximum value within the first time period. The value range of the second acceleration is 5000 to 20000 RPM / S.

[0025] According to any of the foregoing embodiments of this application, step S42 includes

[0026] During the second time period following the first time period, the acceleration of the wafer is changed so that the wafer speed reaches the second predetermined rotational speed.

[0027] The wafer is driven to rotate at a second predetermined speed for a period of less than or equal to 40 seconds, so as to form a photoresist coating of uniform thickness on the first surface of the wafer.

[0028] According to any of the foregoing embodiments of this application, when the fourth predetermined amount of photoresist is started to be dropped onto the center of the wafer, the photoresist dropper used to drop the photoresist onto the wafer is kept relatively stationary with respect to the wafer.

[0029] According to any of the foregoing embodiments of this application, when a fourth predetermined amount of photoresist is dropped onto the center of the wafer, the photoresist dropper used to drop the photoresist onto the wafer has the same rotation speed as the wafer or is stationary.

[0030] According to any of the foregoing embodiments of this application, the formula for calculating the second predetermined rotational speed is as follows:

[0031]

[0032] Where A represents the rotational speed required for the wafer to reach the target photoresist thickness.

[0033] B represents the size of the wafer.

[0034] C represents the average value of the currently measured wafer photoresist film thickness.

[0035] D represents the average thickness of the target photoresist on the wafer.

[0036] E represents the current rotational speed of the wafer.

[0037] F represents the correction factor, and the value of the correction factor is related to the viscosity of the photoresist.

[0038] According to any of the foregoing embodiments of this application, the adhesive is HMDS;

[0039] or

[0040] The first liquid is deionized water or a thinner that can remove the photoresist.

[0041] According to any of the foregoing embodiments of this application, the value of the first predetermined amount ranges from 1 mL to 3 mL; and / or

[0042] The second predetermined amount is in the range of 3 mL to 5 mL; and / or

[0043] The third predetermined amount is in the range of 0.1 mL to 0.5 mL, and / or

[0044] The fourth predetermined amount ranges from 1 mL to 5 mL.

[0045] According to any of the foregoing embodiments of this application, the duration of the first pre-rinsing stage is less than 20 seconds; the duration of the second pre-rinsing stage is less than 30 seconds.

[0046] According to any of the foregoing embodiments of this application, during the first stage of pre-rinsing, the rotational speed of the wafer gradually increases, and then it rotates at a constant speed.

[0047] According to any of the foregoing embodiments of this application, the maximum value of the first acceleration ranges from 100 to 200 RPM / s; and / or

[0048] During the first stage of pre-rinsing, the maximum rotational speed of the wafer ranges from 1000 to 2000 RPM; and / or

[0049] During the second stage of pre-rinsing, the acceleration of the wafer is instantaneously increased to 5000-15000 RPM / s so that the rotational speed of the wafer reaches a first predetermined speed, the value of which is in the range of 2000-3000 RPM.

[0050] The photoresist coating method of this application embodiment, before spraying the adhesive, removes particulate matter from the wafer surface by dropping a first liquid onto the wafer surface and driving the first liquid towards the wafer edge, thereby improving the cleanliness of the wafer surface; after spraying the adhesive, by spreading the first liquid on the wafer surface, the first liquid, as it moves from the drop point to the wafer edge, exerts a pushing force on the adhesive sprayed on the first surface of the wafer, flattening the atomized adhesive accumulation, thereby making the adhesive evenly spread and distributed on the first surface of the wafer. The uniform distribution of HMDS changes the wafer interface structure, thereby changing the wafer's properties from a hydrophilic surface to a hydrophobic surface, which can increase the adhesion of the photoresist and improve the uniformity of the photoresist.

[0051] Furthermore, the subsequent photoresist spin coating process is divided into two time periods. In the first time period, the second acceleration value increases rapidly. This is to ensure that the photoresist, after being dropped onto the first surface of the wafer, is instantly sprayed across the entire surface, spreading out and preventing peak defects from forming at the drop sites. In the second time period, the wafer rotates at a constant speed, ensuring high uniformity of the spread photoresist within the target thickness. This entire photoresist coating method can spin-coat ultra-thin (below 100nm) photoresist with high uniformity (non-uniformity <1%) on the wafer surface. Attached Figure Description

[0052] Figure 1 This is a schematic diagram of the wafer structure according to an embodiment of this application;

[0053] Figure 2 A flowchart of the photoresist coating method according to an embodiment of this application;

[0054] Figure 3 This is a graph showing the rotational speed and rotational acceleration of the rotary motor used in the photoresist coating method of this application embodiment;

[0055] Figure 4 This is a schematic diagram of the structure of the hot and cold cavity used in the photoresist coating method of this application embodiment;

[0056] Figure 5 This is a schematic diagram of the working process of the photoresist coating unit cavity used in the photoresist coating method of this application embodiment;

[0057] Figure 6 This is a contour map of a 6-inch wafer coated with photoresist obtained using the photoresist coating method described in this application.

[0058] Figure 7 This is a contour map of photoresist coating on an 8-inch wafer obtained using the photoresist coating method described in this application.

[0059] Figure 8 This is a 12-inch wafer photoresist coating contour map obtained using the photoresist coating method of the embodiments of this application;

[0060] Figure 9 This is a schematic diagram illustrating the defects of traditional adhesive coating processes. Detailed Implementation

[0061] The features and exemplary embodiments of various aspects of this application will be described in detail below. To make the objectives, technical solutions, and advantages of this application clearer, the application will be further described in detail below with reference to the accompanying drawings and specific embodiments. It should be understood that the specific embodiments described herein are only intended to explain this application and not to limit it. For those skilled in the art, this application can be implemented without some of these specific details. The following description of the embodiments is merely to provide a better understanding of this application by illustrating examples.

[0062] A wafer is a silicon chip used to fabricate silicon semiconductor circuits. Its raw material is silicon, and they are generally available in sizes such as 6 inches, 8 inches, and 12 inches. The larger the diameter, the lower the cost per chip, but the more difficult it is to manufacture. The shape of a wafer is as follows... Figure 1 As shown, the wafer S04 is a circular thin sheet, including a first surface 1 and a second surface (not shown in the figure) opposite each other, and photoresist is applied on the first surface 1.

[0063] Please see Figure 2 This application provides a photoresist coating method for coating photoresist on the surface of a wafer. The method includes steps S1 to S4, wherein steps S1, S3, and S4 are all performed within a coating unit cavity for coating the wafer.

[0064] S1. A first liquid is dripped onto the first surface of the wafer to pre-wet the wafer. The purpose of pre-wetting is to remove particulate matter from the wafer surface. Pre-wetting includes a first pre-wetting stage and a second pre-wetting stage performed sequentially. In the first pre-wetting stage, a first predetermined amount of the first liquid is dripped onto the first surface of the wafer, and then the wafer is driven to rotate at a first acceleration. Under the action of centrifugal force, the first liquid moves towards the edge of the wafer, thereby carrying the particulate matter on the first surface of the wafer towards the edge. In the second pre-wetting stage, a second predetermined amount of the first liquid is dripped onto the first surface of the wafer, and then the acceleration of the wafer is instantaneously increased so that the rotational speed of the wafer reaches a first predetermined speed. The instantaneous surge in acceleration causes the particulate matter at the edge of the wafer to be thrown off the wafer surface. Then, the wafer is driven to rotate at a uniform speed at the first predetermined speed. The remaining particulate matter merges into the water droplets and falls off under its own gravity, thereby detaching from the wafer surface. The first predetermined speed is greater than the maximum rotational speed of the wafer during the first pre-wetting stage.

[0065] Although there are dedicated cleaning processes in chip manufacturing, trace particles still adhere to the wafer surface during the transport of the wafer from the cleaning station to the photoresist coating station. These particles are very small and invisible to the naked eye. While these trace particles have little impact on the coating and exposure processes for thicker photoresist films (e.g., photoresist films larger than 100nm), they can significantly affect the uniformity of ultrathin photoresist films (below 100nm), thereby reducing process yield.

[0066] In step S1 of this embodiment, within the coating unit cavity, the movement of the first liquid from the wafer center to the wafer edge allows it to carry away particulate matter from the first surface. The first liquid can be a thinner for cleaning the photoresist or deionized water. In this embodiment, deionized water is preferred; using deionized water to clean particulate matter reduces costs. Furthermore, since the wafer is pre-rinsed with deionized water, if any deionized water residue remains on the wafer, the temperature of the HMDS coating unit cavity is greater than 90°C, allowing the residual water to evaporate quickly. Compared to using a thinner, deionized water reduces costs.

[0067] In practice, a nozzle capable of spraying deionized water is moved to the center of the wafer coated with adhesive, above the first surface of the wafer. Deionized water is dripped onto the center of the first surface, and then the wafer is driven to rotate. Under the action of centrifugal force, the deionized water carries the particles on the wafer surface and is thrown off the wafer surface.

[0068] In some embodiments, the total volume of the first and second predetermined amounts of liquid ranges from 4 mL to 8 mL, ensuring thorough cleaning. For example, the range of the first and second predetermined amounts can be 1 mL to 3 mL, and the range of the second predetermined amount can be 3 mL to 5 mL.

[0069] S2. Spray an adhesive on the first surface of the wafer to improve the adhesion of the photoresist.

[0070] The binder improves the adhesion between the wafer and the photoresist, ensuring that the photoresist adheres firmly to the first surface of the wafer during subsequent spin coating. In some embodiments, the binder may be hexamethyldisilazane (HMDS).

[0071] In some instances, the binder is sprayed onto the first surface of the wafer using a vapor phase spraying method. This method transforms liquid HMDS into a gaseous state, coating and adsorbing it onto the wafer surface, thus improving HMDS utilization and reducing costs. Specifically, step S1 includes:

[0072] S21. Send the wafer into the binder unit cavity and keep the temperature inside the binder unit cavity greater than or equal to 90°C.

[0073] S22. Spray the vapor-phase binder onto the first surface of the wafer.

[0074] Preferably, the temperature within the adhesive unit cavity is in the range of 90°C to 200°C. This temperature range can maintain the adhesive in a stable gaseous state without changing the properties of HMDS, which is beneficial to the uniformity of HMDS coating on the wafer surface.

[0075] S3. A third predetermined amount of the first liquid is dropped onto the first surface of the wafer. The wafer is then rotated so that the first liquid moves from the drop point toward the edge of the wafer. Through the movement of the first liquid, the adhesive adsorbed on the first surface of the wafer in the gas phase is uniformly spread on the first surface of the wafer by the liquid, ensuring uniform adsorption of the photoresist to the wafer surface and ensuring high adhesion. This is the third stage of pre-rinsing.

[0076] If the time for spraying the vapor phase binder onto the first surface of the wafer is too short, unevenness will occur, which may lead to uneven photoresist thickness in subsequent processes, resulting in a low yield for the photolithography spin coating process. Step S3, as the first liquid moves from the droplet point towards the wafer edge, it exerts a pushing force on the binder sprayed on the first surface of the wafer, spreading the accumulated binder evenly and thus ensuring uniform distribution of the binder on the first surface of the wafer. Step S3 shortens the time for spraying the binder onto the first surface of the wafer, improving the spin coating efficiency of the photoresist.

[0077] In practice, a nozzle capable of spraying deionized water is moved to the center of the wafer coated with adhesive, above the first surface of the wafer. A third predetermined amount of deionized water is dripped onto the center of the first surface. Then, the wafer is rotated at a high acceleration, so that the deionized water can instantly spread the adhesive adsorbed on the wafer surface under the action of a large centrifugal force, thereby increasing the spreading area of ​​the adhesive.

[0078] In some embodiments, step S3 includes steps S31 and S32.

[0079] S31. A third predetermined amount of first liquid is dropped onto the first surface of the wafer, and the acceleration of the wafer is instantly increased so that the wafer reaches the third predetermined rotation speed; for example, within 0.1 to 1 second after the first liquid is dropped onto the first surface of the wafer, the wafer is rotated, the rotation acceleration is increased to 10000 RPM / S, and the rotation speed is increased to 3000 RPM, so that the first liquid on the wafer surface is subjected to a large centrifugal force and is instantly thrown to the edge of the wafer. During the movement of the first liquid, the accumulated adhesive is evenly spread on the first surface of the wafer.

[0080] S32. Rotate the wafer at a third predetermined speed. If the wafer speed was increased to 3000 RPM in step S31, then the second predetermined speed is 3000 RPM. The time for the wafer to rotate at the third predetermined speed is less than 20 seconds. Through step S32, any liquid or small water droplets that were not shaken off from the wafer edge can be made to gather together and grow larger through uniform rotation, and then fall off under the action of gravity, ensuring that no defects are generated at the edge after coating.

[0081] If the wafer rotates at the third predetermined speed for too long, too much HMDS will be carried away, the adhesion of the wafer edge will be reduced, and the probability of coating defects at the wafer edge will increase.

[0082] In traditional adhesive spraying processes, if the adhesive spraying time is too short, it will lead to uneven distribution of the adhesive on the wafer surface, resulting in localized accumulation. To ensure uniform coverage of the wafer surface, spraying the adhesive for more than 2 minutes is often necessary. This prolonged spraying time not only increases the overall coating process time but also consumes a large amount of adhesive to achieve uniform coverage on the mirror surface, with most of the adhesive dripping to the bottom of the adhesive unit cavity under gravity. In this embodiment, steps S31 and S32 allow the previously accumulated adhesive to spread rapidly on the first surface. Therefore, in step S2, it is unnecessary to spray the adhesive on the first surface for an excessively long time to achieve uniform coverage. In some embodiments, the adhesive spraying time on the first surface of the wafer can be less than or equal to 40 seconds. Compared to the traditional process of spraying adhesive on the first surface for more than 2 minutes, the adhesive spraying time is significantly reduced.

[0083] In some embodiments, the third predetermined amount ranges from 0.1 mL to 0.5 mL. Since the function of the first liquid is to evenly spread the accumulated adhesive, it should not be too little or too much. Too little will not achieve the purpose of evenly spreading the adhesive, while too much will waste the first liquid, increase rotation time, and cause excessive residue of the first liquid on the wafer, affecting subsequent coating processes. A range of 0.1 mL to 0.5 mL allows the adhesive to be evenly spread, enhances adhesion, improves coating uniformity, and results in a higher yield for wafer processing.

[0084] S4. Drop a fourth predetermined amount of photoresist onto the center of the wafer, and drive the wafer to rotate so that the fourth predetermined amount of photoresist is uniformly coated on the first surface of the wafer.

[0085] Step S1 cleans all particles from the wafer surface. Steps S2 and S3 allow the adhesive to be quickly and evenly applied to the first surface of the wafer. Step S4 then coats an ultra-thin and uniform photoresist film onto the wafer surface.

[0086] In some embodiments, step S4 includes steps S41 and S42.

[0087] S41. A fourth predetermined amount of photoresist is dropped onto the center of the wafer. During a first time period after the photoresist is dropped, the wafer is driven to rotate with a second acceleration so that the fourth predetermined amount of photoresist is spread on the first surface.

[0088] S42. During a second time period following the first time period, the wafer is driven to rotate at a second predetermined speed to form a photoresist coating of uniform thickness on the first surface of the wafer; wherein the first time period is shorter than the second time period.

[0089] In traditional photoresist coating processes, when photoresist is dropped onto the wafer, the wafer at the bottom is already rotating at a uniform speed, causing the photoresist to spread on the wafer surface. This process easily creates bumps at the drop sites, increasing the non-uniformity of the photoresist coating within the nanometer thickness range. In step S4 of this embodiment, the first time period is shorter than the second time period. During the first time period, the value of the second acceleration increases rapidly, the purpose of which is to ensure that the photoresist is instantly flung to all parts of the first surface of the wafer after being dropped, spreading it evenly and preventing the formation of peaks at the drop sites. During the second time period, the wafer rotates at a uniform speed, ensuring that the spread photoresist maintains high uniformity within the target thickness range.

[0090] In some embodiments, the first time period is less than or equal to 5 seconds, and the second acceleration rapidly increases from its initial value to its maximum value within the first time period. The maximum value of the second acceleration is greater than or equal to 5000 RPM / s and less than or equal to 20000 RPM / s. Utilizing the instantaneously increased second acceleration enhances the centrifugal force of the photoresist dripped onto the wafer center, reducing the photoresist thickness at the wafer center and preventing convex defects. Too small a second acceleration value is insufficient to resolve the peak-shaped defects of the photoresist at the wafer center; too large a second acceleration value (e.g., greater than 20000 RPM / s) will generate excessive centrifugal force, causing the photoresist to separate from the wafer surface and resulting in voids at the interface in localized areas. Therefore, the value range of the second acceleration is preferably between 5000 RPM / s and 20000 RPM / s.

[0091] In some embodiments, step S42 specifically includes: during a second time period after the first time period, changing the acceleration of the wafer to make the wafer speed reach a second predetermined rotational speed, driving the wafer to rotate uniformly at the second predetermined rotational speed for a time less than or equal to 40 seconds, so as to form a photoresist coating of uniform thickness on the first surface of the wafer. During the second time period, the rotational acceleration of the wafer is reduced to zero, making the wafer rotate uniformly at the predetermined rotational speed. Maintaining a constant rotational speed of the wafer can reduce the airflow velocity at the wafer edge, solving the problem of uniform photoresist coating at the wafer edge.

[0092] In some embodiments, to improve the prediction efficiency of the second predetermined speed and reduce the trial-and-error rate, the second predetermined speed is calculated by the following formula:

[0093]

[0094] Where A represents the rotational speed required for the wafer to reach the target photoresist thickness, B represents the wafer size (inches), C represents the average measured photoresist film thickness on the wafer, D represents the average target photoresist thickness on the wafer, E represents the current rotational speed of the wafer, and F represents a correction factor (a dimensionless parameter). The value of the correction factor is related to the selection of photoresist; different photoresists have different viscosities, resulting in different correction factors. This calculation formula allows for a relatively quick prediction of the rotational speed required for the wafer to reach the target photoresist thickness.

[0095] In some embodiments, to improve the uniformity of the photoresist coating thickness, when a fourth predetermined amount of photoresist is dispensed onto the center of the wafer, the photoresist dropper used for dispensing the photoresist onto the wafer remains relatively stationary. In conventional photoresist dispensing processes, the wafer is generally rotating at a uniform speed when dispensing photoresist onto the wafer surface. This can lead to uneven forces acting on the photoresist in a certain direction when it contacts the wafer surface, resulting in a thicker photoresist layer in one direction or region compared to other directions or regions. In the embodiments of this application, when dispensing photoresist onto the wafer surface, the photoresist dropper used for dispensing the photoresist onto the wafer remains relatively stationary. This prevents the photoresist from experiencing uneven forces due to the rotational speed difference between the photoresist and the wafer when it is dispensed onto the wafer surface, thereby making the photoresist coating thickness more uniform.

[0096] In some embodiments, when a fourth predetermined amount of photoresist is applied to the center of the wafer, the photoresist dropper used for applying the photoresist to the wafer rotates at the same speed as the wafer or is stationary. Preferably, to improve efficiency, when applying the fourth predetermined amount of photoresist to the center of the wafer, the photoresist dropper used for applying the photoresist to the wafer rotates at the same speed as the wafer, and their axes of rotation coincide. Since the wafer has already started rotating in step S2 before applying the photoresist, to avoid a shutdown and restart, and to maintain the current rotational state of the wafer, the photoresist dropper rotates at the same speed as the wafer, and their axes of rotation coincide. In this way, when the photoresist is applied to the wafer, it remains relatively stationary, and the photoresist is subjected to uniform force in all directions at the wafer interface.

[0097] In some embodiments, the fourth predetermined amount ranges from 1 mL to 5 mL. For photoresist films with a thickness of less than 100 nm, if too much photoresist is dispensed onto the wafer surface, it will lead to waste. Furthermore, the photoresist dropper may need to dispense photoresist several times to complete the dispensing step, and air will enter during the dispensing intervals, resulting in air bubbles in the photoresist dispensed onto the wafer surface. In the embodiments of this application, a dispensing amount of 1 mL to 5 mL can meet the photoresist thickness requirements, while also ensuring that the photoresist is dispensed onto the wafer surface only once, preventing air bubbles from being generated in the photoresist after multiple dispensing steps.

[0098] In some embodiments, step SP is included after step S2.

[0099] SP: The wafer is fed into the cooling chamber, and the temperature of the cooling chamber is reduced to 20℃~30℃. Since the temperature of the wafer is relatively high (greater than 90℃) in the adhesive unit chamber, it is fed into the cooling chamber to reduce the temperature of the cooling chamber to 20℃~30℃ in order to cool the wafer quickly. This allows the atomized HMDS to be more readily adsorbed on the wafer surface, which is beneficial for the subsequent adhesive coating step.

[0100] In some embodiments, during the first pre-rinsing stage, the wafer's rotational speed gradually increases and then remains constant; or the wafer's first acceleration gradually increases and then decreases to zero. During the first pre-rinsing stage, while a predetermined amount of first liquid is dripped onto the wafer's first surface, the wafer is driven to accelerate and rotate, then rotated at a constant speed. For example, within 5 to 15 seconds, the wafer's first acceleration increases to 200 RPM / s, and the wafer's rotational speed increases to 2000 RPM, then it rotates at a constant speed of 2000 RPM. This step allows particles on the wafer surface to move and accumulate towards the wafer edge under the influence of the first liquid. Preferably, the duration of the first pre-rinsing stage can be less than 20 seconds; the maximum value of the first acceleration ranges from 100 to 200 RPM / s, and the maximum rotational speed of the wafer during the first pre-rinsing stage ranges from 1000 to 2000 RPM. These parameter values ​​allow most of the particles on the wafer surface to move and accumulate towards the wafer edge with the first liquid in a relatively short time.

[0101] In some embodiments, during the second pre-rinsing stage, the wafer's acceleration is first instantaneously increased to bring it to a first predetermined rotational speed; for example, within 0.1 to 0.5 seconds, the wafer's acceleration increases to 10,000 RPM / s, and the rotational speed increases to 3,000 RPM. This instantaneous acceleration causes the first liquid on the wafer surface to be subjected to a large centrifugal force, instantly being thrown off the wafer surface. This step removes approximately 90% of the particles from the wafer surface; the remaining particles remain attached to the wafer edge. The wafer is then driven to rotate uniformly at the first predetermined rotational speed (e.g., 3,000 RPM), which is greater than the maximum rotational speed of the wafer during the first pre-rinsing stage (e.g., 2,000 RPM). This step causes the remaining particles and deionized water at the wafer edge to fall off under gravity, thus detaching from the wafer surface. Preferably, the duration of the second pre-rinsing stage is less than 30 seconds; the acceleration of the wafer is instantaneously increased to 5000-15000 RPM / s so that the wafer rotation speed reaches the first predetermined rotation speed, the value of the first predetermined rotation speed is in the range of 2000-3000 RPM; the above parameter values ​​can make the particles on the wafer surface detach from the wafer surface in a short time.

[0102] By using the above step S1, coating defects caused by particles on the wafer surface can be avoided, thus increasing the yield of the ultra-thin coating process.

[0103] To facilitate understanding of the embodiments of this application, specific embodiments are provided below for further explanation. These embodiments do not constitute a limitation on the embodiments of this application.

[0104] Example 1

[0105] Step 1: Place the FOUP (Front Opening Unified Pod) containing the 6-inch wafer onto the stage.

[0106] Step 2: Feed the 6-inch wafer into the coating unit cavity. A schematic diagram of the coating unit cavity is shown below. Figure 5 As shown, the wafer is transferred to the chuck of the rotary motor S06, and the wafer S04 is fixed.

[0107] Step 3: Move the nozzle S02, capable of spraying deionized water, to above the center of the wafer substrate. Adjust the direction of the nozzle S03 to pre-rinse the wafer. Pre-rinsing consists of three stages. The first two stages are performed in this step, and the third stage is performed in step six. First stage (first pre-rinsing stage): Within 20 seconds after dripping 1 mL of deionized water onto the first surface of the wafer, control the wafer's acceleration to increase to 100–200 RPM / s and its rotation speed to increase to 1000–2000 RPM. This will carry particles from the center of the wafer to the wafer edge through the rotation of the liquid. Second stage (second pre-rinsing stage): Maintaining the rotation speed of the first pre-rinsing stage, drip 3 mL of deionized water onto the first surface of the wafer. Then, within 0.1–0.5 seconds, control the wafer's acceleration to increase to 5000–10000 RPM / s and its rotation speed to increase to 2000–3000 RPM (reaching the first predetermined rotation speed), and then rotate at a constant speed for 10 seconds. By utilizing the instantaneous acceleration and increased centrifugal force, particles at the edge of the wafer are flung off the wafer surface. Then, the wafer rotates at a constant speed, and the remaining particles merge into water droplets and fall off the surface under their own gravity. This reduces the occurrence of coating defects caused by particles on the wafer surface and increases the yield of the ultra-thin coating process.

[0108] Step 4: After the first two stages of pre-wetting are completed, the wafer is sent into the adhesive unit cavity. The temperature of the adhesive unit cavity is between 90 and 100°C. HMDS (hexamethyldisilazane) vapor is sprayed onto the silicon wafer surface for 10 to 15 seconds. The purpose is to increase the adhesion between the wafer surface and the photoresist. Through the first two pre-wetting processes, the wafer surface is ensured to be in full contact with the vapor HMDS.

[0109] Step 5: After HMDS coating, the wafer enters the cooling chamber. A schematic diagram of the cooling chamber is shown below. Figure 4As shown, the wafer is rapidly cooled to 25°C.

[0110] Step Six: The wafer enters the coating unit cavity. A schematic diagram of the coating unit cavity is shown below. Figure 5 As shown, the cooled wafer is transferred to the chuck of the rotary motor S06, where it is fixed by S04. The nozzle S02 is moved to the center above the wafer substrate coated with HMDS. The direction of the nozzle S03 is adjusted, and 0.3 mL of deionized water is dripped onto the wafer for the third stage of pre-rinsing. The wafer is then rotated clockwise (or counterclockwise). Within 0.3 to 1 second, the acceleration of the stationary wafer substrate increases to 3000 to 10000 RPM / s, and the rotation speed increases to 1000 to 3000 RPM (reaching the third predetermined speed). Then, it continues to rotate at a constant speed for 10 seconds. Instantly, the HMDS (hexamethyldisilazane) adsorbed on the silicon wafer is evenly spread on the first surface of the wafer, providing a foundation for high adhesion and high uniformity of the adhesive coating.

[0111] Step 7: After pre-rinsing, move the photoresist dropper S01 tube above the center of the wafer and drop 3 mL of photoresist onto the wafer. After the photoresist is dropped, drive the wafer to rotate. The wafer rotation process includes two stages. In the first stage, at the moment of photoresist dropping, the speed is accelerated to 3000-8000 RPM / s within 2-5 seconds, and the rotation speed is increased to 1000-3000 RPM (reaching the second predetermined speed), spreading the photoresist from the center of the wafer to the wafer surface. In the second stage, the rotation acceleration is reduced to maintain the acceleration corresponding to the predetermined speed calculated by the empirical formula (1) for the speed, and then the acceleration is reduced to 0 RPM / s, and the uniform motion continues. The correction factor in the empirical formula is related to the viscosity of the photoresist. When the viscosity of the photoresist is 500-3000 centipoise, the corresponding correction factor is 0.05-0.2. The uniform rotation time is 30-40 seconds, and the corresponding coating thickness is obtained. The above motor rotates clockwise (or counterclockwise) in the direction S07, sputtering onto the photoresist adsorption tank S05. Due to the smooth surface, the photoresist slides down quickly, preventing the photoresist from splashing back onto the wafer.

[0112] Step 8: After the photoresist coating is completed, move the nozzle S02, adjust the nozzle S03, switch the liquid in the pipeline to diluent, and clean the back side and edge of the wafer. Adjust the nozzle direction to clean the residual photoresist on the back side and edge of the wafer.

[0113] Step 9: After the adhesive coating is completed, the wafer is sent into the cooling chamber. A schematic diagram of the cooling chamber is shown below. Figure 4 As shown, the temperature is rapidly increased to 120℃ for curing.

[0114] The wafers are randomly sampled, and their adhesive surface non-uniformity is measured. The formula for calculating adhesive surface non-uniformity is as follows: Where M max M represents the maximum thickness of the photoresist film on the sampled wafers. minL represents the minimum photoresist film thickness of the sampled wafers. average This indicates the average thickness of the photoresist film on the sampled wafers; a non-uniformity of ≤1% is considered acceptable, and only acceptable products can proceed to the exposure machine for exposure. Figure 6 The 6-inch wafer in this embodiment has a coating thickness of [missing information]. The contour map at that time, after calculation, shows that its non-uniformity meets the requirements. Therefore, it can be seen that the embodiments of this application solve the problem. Figure 9 The defects of the traditional adhesive coating process are shown.

[0115] Example 2

[0116] Step 1: Place the FOUP containing the 8-inch wafer onto the stage.

[0117] Step 2: Feed the 8-inch wafer into the coating unit cavity. A schematic diagram of the coating unit cavity is shown below. Figure 5 As shown, the wafer is transferred to the chuck of the rotary motor S06, and the wafer S04 is fixed.

[0118] Step 3: Move the nozzle S02, capable of spraying deionized water, to above the center of the wafer substrate. Adjust the direction of the nozzle S03 to pre-rinse the wafer. Pre-rinsing consists of three stages. The first two stages are performed in this step, and the third stage is performed in step six. First stage (first pre-rinsing stage): Within 20 seconds after dripping 2 mL of deionized water onto the first surface of the wafer, control the wafer's acceleration to increase to 100–200 RPM / s and its rotation speed to increase to 1000–2000 RPM. This will carry particles from the center of the wafer to the wafer edge through the rotation of the liquid. Second stage (second pre-rinsing stage): Maintaining the rotation speed of the first pre-rinsing stage, drip 4 mL of deionized water onto the first surface of the wafer. Then, within 0.1–0.5 seconds, control the wafer's acceleration to increase to 5000–10000 RPM / s and its rotation speed to increase to 2000–3000 RPM (reaching the first predetermined rotation speed), and then rotate at a constant speed for 10 seconds. By utilizing the instantaneous acceleration and increased centrifugal force, particles at the edge of the wafer are flung off the wafer surface. Then, the wafer rotates at a constant speed, and the remaining particles merge into water droplets and fall off the surface under their own gravity. This reduces the occurrence of coating defects caused by particles on the wafer surface and increases the yield of the ultra-thin coating process.

[0119] Step 4: After the first two stages of pre-wetting are completed, the wafer is sent into the adhesive unit cavity. The temperature of the adhesive unit cavity is between 90 and 100°C. HMDS (hexamethyldisilazane) vapor is sprayed onto the silicon wafer surface for 12 to 15 seconds. The purpose is to increase the adhesion between the wafer surface and the photoresist. Through the first two pre-wetting processes, the wafer surface is ensured to be in full contact with the vapor HMDS.

[0120] Step 5: After HMDS coating, the wafer enters the cooling chamber. A schematic diagram of the cooling chamber is shown below. Figure 4 As shown, the wafer is rapidly cooled to 25°C.

[0121] Step Six: The wafer enters the coating unit cavity. A schematic diagram of the coating unit cavity is shown below. Figure 5 As shown, the cooled wafer is transferred to the chuck of the rotary motor S06, fixed by the wafer S04, and moved to the center above the HMDS-coated wafer substrate by the nozzle S02. The direction of the nozzle S03 is adjusted, and 0.4 mL of deionized water is dripped onto the wafer to perform the third stage of pre-rinsing. The wafer is rotated clockwise (or counterclockwise). Within 0.3 to 1 second, the rotational acceleration of the stationary wafer substrate increases to 3000 to 10000 RPM / s, and the rotational speed increases to 1000 to 3000 RPM (reaching the third predetermined speed). Then, it continues to rotate at a constant speed for 15 seconds. Instantly, the HMDS (hexamethyldisilazane) adsorbed on the silicon wafer is evenly spread on the first surface of the wafer, providing a basis for high adhesion and high uniformity of the adhesive coating.

[0122] Step 7: After pre-rinsing, move the photoresist dropper S01 tube above the center of the wafer and drop 4 mL of photoresist onto the wafer. After the photoresist is dropped, drive the wafer to rotate. The wafer rotation process includes two stages. In the first stage, at the moment of photoresist dropping, the speed is accelerated to 3000-8000 RPM / s within 2-5 seconds, and the rotation speed is increased to 1000-3000 RPM (reaching the second predetermined speed), spreading the photoresist from the center of the wafer to the wafer surface. In the second stage, the rotation acceleration is reduced to maintain the acceleration corresponding to the predetermined speed calculated by the empirical formula (1) for the speed, and then the acceleration is reduced to 0 RPM / s, and the uniform motion continues. The correction factor in the empirical formula is related to the viscosity of the photoresist. When the viscosity of the photoresist is 500-3000 centipoise, the corresponding correction factor is 0.05-0.2. The uniform rotation time is 35-40 seconds, and the corresponding coating thickness is obtained. The above motor rotates clockwise (or counterclockwise) in the direction S07, sputtering onto the photoresist adsorption tank S05. Due to the smooth surface, the photoresist slides down quickly, preventing the photoresist from splashing back onto the wafer.

[0123] Step 8: After the photoresist coating is completed, move the nozzle S02, adjust the nozzle S03, switch the liquid in the pipeline to diluent, and clean the back side and edge of the wafer. Adjust the nozzle direction to clean the residual photoresist on the back side and edge of the wafer.

[0124] Step 9: After the adhesive coating is completed, the wafer is sent into the cooling chamber. A schematic diagram of the cooling chamber is shown below. Figure 4 As shown, the temperature is rapidly increased to 120°C for curing.

[0125] The wafers are randomly sampled, and their adhesive surface non-uniformity is measured. The formula for calculating adhesive surface non-uniformity is as follows: A non-uniformity of ≤1% is considered acceptable, and only acceptable products can be exposed in the exposure machine. Figure 7The 8-inch wafer in this embodiment has a coating thickness of [missing information]. The contour map at that time, after calculation, shows that its non-uniformity meets the requirements. Therefore, it can be seen that the embodiments of this application solve the problem. Figure 9 The defects of the traditional adhesive coating process are shown.

[0126] Example 3

[0127] Step 1: Place the FOUP containing the 12-inch wafer onto the stage.

[0128] Step 2: Feed the 12-inch wafer into the coating unit cavity. A schematic diagram of the coating unit cavity is shown below. Figure 5 As shown, the wafer is transferred to the chuck of the rotary motor S06, and the wafer S04 is fixed.

[0129] Step 3: Move the nozzle S02, capable of spraying deionized water, to above the center of the wafer substrate. Adjust the direction of the nozzle S03 to pre-rinse the wafer. Pre-rinsing consists of three stages. The first two stages are performed in this step, and the third stage is performed in step six. First stage (first pre-rinsing stage): Within 20 seconds after dripping 4 mL of deionized water onto the first surface of the wafer, control the wafer's acceleration to increase to 100–200 RPM / s and its rotation speed to increase to 1000–2000 RPM. This will carry particles from the center of the wafer to the wafer edge through the rotation of the liquid. Second stage (second pre-rinsing stage): Maintaining the rotation speed of the first pre-rinsing stage, drip 5 mL of deionized water onto the first surface of the wafer. Then, within 0.1–0.5 seconds, control the wafer's acceleration to increase to 5000–10000 RPM / s and its rotation speed to increase to 2000–3000 RPM (reaching the first predetermined rotation speed), and then rotate at a constant speed for 10 seconds. By utilizing the instantaneous acceleration and increased centrifugal force, particles at the edge of the wafer are flung off the wafer surface. Then, the wafer rotates at a constant speed, and the remaining particles merge into water droplets and fall off the surface under their own gravity. This reduces the occurrence of coating defects caused by particles on the wafer surface and increases the yield of the ultra-thin coating process.

[0130] Step 4: After the first two stages of pre-wetting are completed, the wafer is sent into the adhesive unit cavity. The temperature of the adhesive unit cavity is between 90 and 100°C. HMDS (hexamethyldisilazane) vapor is sprayed onto the silicon wafer surface for 13 to 15 seconds. The purpose is to increase the adhesion between the wafer surface and the photoresist. Through the first two pre-wetting processes, the wafer surface is ensured to be in full contact with the vapor HMDS.

[0131] Step 5: After HMDS coating, the wafer enters the cooling chamber. A schematic diagram of the cooling chamber is shown below. Figure 4 As shown, the wafer is rapidly cooled to 25°C.

[0132] Step Six: The wafer enters the coating unit cavity. A schematic diagram of the coating unit cavity is shown below. Figure 5 As shown, the cooled wafer is transferred to the chuck of the rotary motor S06, and the wafer is fixed by S04. The nozzle S02 is moved to the center above the wafer substrate coated with HMDS. The direction of the nozzle S03 is adjusted, and 0.5 mL of deionized water is dripped onto the wafer to perform the third stage of pre-rinsing. The wafer is rotated clockwise (or counterclockwise). Within 0.3 to 1 second, the acceleration of the stationary wafer substrate increases to 3000 to 10000 RPM / s, and the rotation speed increases to 1000 to 3000 RPM (reaching the third predetermined speed). Then, it continues to rotate at a constant speed for 18 seconds. Instantly, the HMDS (hexamethyldisilazane) adsorbed on the silicon wafer is evenly spread on the first surface of the wafer, providing a basis for high adhesion and high uniformity of the adhesive coating.

[0133] Step 7: After pre-rinsing, move the photoresist dropper S01 tube above the center of the wafer and drop 5 mL of photoresist onto the wafer. After the photoresist is dropped, drive the wafer to rotate. The wafer rotation process includes two stages. In the first stage, at the moment of photoresist dropping, the speed is accelerated to 3000-8000 RPM / s within 2-5 seconds, and the rotation speed is increased to 1000-3000 RPM (reaching the second predetermined speed), spreading the photoresist from the center of the wafer to the wafer surface. In the second stage, the rotation acceleration is reduced to maintain the acceleration corresponding to the predetermined speed calculated by the empirical formula (1) of the speed, and then the acceleration is reduced to 0 RPM / s, and the uniform motion continues. The correction factor in the empirical formula is related to the viscosity of the photoresist. When the viscosity of the photoresist is 500-3000 centipoise, the corresponding correction factor is 0.05-0.2. The uniform rotation time is 35-40 seconds, and the corresponding coating thickness is obtained. The above motor rotates clockwise (or counterclockwise) in the direction S07, sputtering onto the photoresist adsorption tank S05. Due to the smooth surface, the photoresist slides down quickly, preventing the photoresist from splashing back onto the wafer.

[0134] Step 8: After the photoresist coating is completed, move the nozzle S02, adjust the nozzle S03, switch the liquid in the pipeline to thinner, move the nozzle to clean the back side and edge of the wafer, adjust the direction of the nozzle S03, and clean the residual photoresist on the back side and edge of the wafer.

[0135] Step 9: After the adhesive coating is completed, the wafer is sent into the cooling chamber. A schematic diagram of the cooling chamber is shown below. Figure 4 As shown, the temperature is rapidly increased to 120°C for curing.

[0136] The wafers are randomly sampled, and their adhesive surface non-uniformity is measured. The formula for calculating adhesive surface non-uniformity is as follows: A non-uniformity of ≤1% is considered acceptable, and only acceptable products can be exposed in the exposure machine. Figure 8 For this embodiment, the 12-inch wafer has a coating thickness of [missing information]. The contour map at that time, after calculation, shows that its non-uniformity meets the requirements. Therefore, it can be seen that the embodiments of this application solve the problem. Figure 9The defects of the traditional adhesive coating process are shown.

Claims

1. A photoresist coating method for coating photoresist on a wafer surface, characterized in that, The method includes the following steps: S1. A first liquid is dropped onto the first surface of the wafer to pre-wet the wafer. The pre-wetting includes a first pre-wetting stage and a second pre-wetting stage performed sequentially. In the first stage of the pre-rinsing, a first predetermined amount of first liquid is dropped onto the first surface of the wafer, driving the wafer to rotate with a first acceleration. In the second stage of pre-rinsing, a second predetermined amount of first liquid is dropped onto the first surface of the wafer. First, the acceleration of the wafer is instantaneously increased so that the rotation speed of the wafer reaches the first predetermined speed. Then, the wafer is driven to rotate at a constant speed at the first predetermined speed, which is greater than the maximum rotation speed of the wafer in the first stage of pre-rinsing. S2. Spray an adhesive to improve the adhesion of the photoresist onto the first surface of the wafer; S3. A third predetermined amount of first liquid is dropped onto the first surface of the wafer, and the wafer is driven to rotate so that the first liquid moves from the dropping point toward the edge of the wafer, so that the adhesive is evenly spread on the first surface of the wafer through the movement of the first liquid. S4. Drop a fourth predetermined amount of photoresist onto the center of the wafer, and drive the wafer to rotate so that the fourth predetermined amount of photoresist is uniformly coated on the first surface of the wafer. Steps S1, S3, and S4 are all performed within the coating unit cavity used for coating the wafer.

2. The photoresist coating method according to claim 1, characterized in that, Step S4 includes the following steps: S41. A fourth predetermined amount of photoresist is dropped onto the center of the wafer. During a first time period after the dropper is completed, the wafer is driven to rotate with a second acceleration so that the fourth predetermined amount of photoresist is spread on the first surface. The second acceleration increases from an initial value to a maximum value during the first time period. S42. During a second time period following the first time period, the wafer is driven to rotate at a second predetermined speed to form a photoresist coating of uniform thickness on the first surface of the wafer. The first time period is shorter than the second time period.

3. The photoresist coating method according to claim 1, characterized in that, Step S2 includes: The wafer is fed into the binder unit cavity, and the vapor-phase binder is sprayed onto the first surface of the wafer. The temperature inside the adhesive unit cavity is greater than or equal to 90℃.

4. The photoresist coating method according to claim 3, characterized in that, After step S2, the wafer is fed into a cooling chamber, and the temperature of the cooling chamber is reduced to 20°C to 30°C.

5. The photoresist coating method according to claim 1, characterized in that, Step S3 includes dropping a third predetermined amount of first liquid onto the first surface of the wafer to increase the acceleration of the wafer so that the wafer reaches a third predetermined rotational speed; The wafer is driven to rotate at a uniform speed at a third predetermined rotational speed; The time for the wafer to rotate at a constant speed at the third predetermined rotation speed is less than 20 seconds.

6. The photoresist coating method according to claim 5, characterized in that, The time for spraying the adhesive onto the first surface of the wafer is less than or equal to 40 seconds.

7. The photoresist coating method according to claim 2, characterized in that, The first time period is less than or equal to 5 seconds, and the second acceleration gradually increases from its initial value to its maximum value within the first time period. The value range of the second acceleration is 5000 RPM / s to 20000 RPM / s.

8. The photoresist coating method according to claim 2, characterized in that, Step S42 includes changing the acceleration of the wafer during a second time period after the first time period so that the wafer speed reaches a second predetermined rotation speed, driving the wafer to rotate at a uniform speed at the second predetermined rotation speed for a time less than or equal to 40 seconds, so as to form a photoresist coating of uniform thickness on the first surface of the wafer.

9. The photoresist coating method according to claim 1, characterized in that, When the fourth predetermined amount of photoresist is dropped onto the center of the wafer, the photoresist dropper used to drop the photoresist onto the wafer remains relatively stationary with respect to the wafer.

10. The photoresist coating method according to claim 9, characterized in that, When a fourth predetermined amount of photoresist is dropped onto the center of the wafer, the photoresist dropper used to drop the photoresist onto the wafer rotates at the same speed as the wafer or is stationary.

11. The photoresist coating method according to claim 2, characterized in that, The formula for calculating the second predetermined rotational speed is as follows: ； Where A represents the rotational speed required for the wafer to reach the target photoresist thickness. B represents the size of the wafer. C represents the average value of the currently measured wafer photoresist film thickness. D represents the average thickness of the target photoresist on the wafer. E represents the current rotational speed of the wafer. F represents the correction factor, and the value of the correction factor is related to the viscosity of the photoresist.

12. The photoresist coating method according to claim 1, characterized in that, The adhesive is HMDS; or, the first liquid is deionized water or a diluent capable of washing away the photoresist.

13. The photoresist coating method according to claim 1, characterized in that, The first predetermined amount ranges from 1 mL to 3 mL, and / or The second predetermined amount is in the range of 3 mL to 5 mL; and / or The third predetermined amount ranges from 0.1 mL to 0.5 mL; and / or The value range of the fourth predetermined amount is 1mL to 5mL.

14. The photoresist coating method according to claim 1, characterized in that, The duration of the first stage of the pre-rinsing is less than 20 seconds; The duration of the second stage of pre-rinsing is less than 30 seconds.

15. The photoresist coating method according to claim 1, characterized in that, During the first stage of pre-rinsing, the rotational speed of the wafer gradually increases, and then it rotates at a constant speed.

16. The photoresist coating method according to claim 1, characterized in that, The maximum value of the first acceleration ranges from 100 to 200 RPM / s; and / or During the first stage of pre-rinsing, the maximum rotational speed of the wafer ranges from 1000 to 2000 RPM; or During the second pre-rinsing stage, the acceleration of the wafer is instantaneously increased to 5000-15000 RPM / s so that the rotational speed of the wafer reaches a first predetermined speed, the first predetermined speed being in the range of 2000-3000 RPM.

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