A photoresist developing method

Abstract

The application provides a photoresist developing method, relates to the technical field of semiconductor manufacturing, and particularly relates to a photoresist developing method. The method comprises the following steps: obtaining a wafer to be developed, wherein the wafer to be developed is a wafer with a photoresist film; exposing the wafer to be developed according to the film thickness of the photoresist film; baking the wafer to be developed according to a preset baking temperature and a preset baking distance, wherein the preset baking temperature increases first and then decreases with the baking time, and the preset baking distance decreases first and then increases with the baking time; and performing a developing process on the wafer to be developed. The method can improve the heating mode of the wafer to be developed in the developing process after exposure, improve the baking effect of the photoresist film, reduce the possibility of defects of the photoresist film, help avoid the excessive flow rate of the non-exposed area, prevent the photoresist film from being greatly deformed, reduce the possibility of image distortion, and provide reliable guarantee for the resolution of the developed image.

Description

Technical Field

[0001] This invention relates to the field of semiconductor manufacturing technology, and more particularly to a photoresist development method. Background Technology

[0002] Photolithography is widely used in the semiconductor industry. Through photolithography, patterns on a photomask are transferred to the wafer surface, thus achieving wafer surface patterning. This process includes processes such as resist coating, baking, exposure, and development, with development being particularly important. Based on current thick resist development technology, products often exhibit defects such as residual photoresist and photoresist deformation, severely affecting the resolution of the developed image. Summary of the Invention

[0003] The present invention aims to solve at least one of the technical problems existing in the prior art or related art.

[0004] Therefore, the present invention provides a photoresist development method, the method comprising:

[0005] Obtain a wafer to be developed, wherein the wafer to be developed is a wafer with a photoresist film;

[0006] Based on the thickness of the photoresist film, the wafer to be developed is exposed.

[0007] The wafer to be developed is baked according to the preset baking temperature and preset baking distance. The preset baking temperature first increases and then decreases with the baking time, and the preset baking distance first decreases and then increases with the baking time.

[0008] The above-mentioned wafer to be developed is subjected to a developing process.

[0009] In one feasible implementation, the wafer to be developed is baked according to a preset baking temperature and a preset baking distance, including:

[0010] The wafer to be developed is baked for a first preset time based on a first preset baking temperature and a first preset baking distance.

[0011] Based on the second preset baking temperature and the second preset baking distance, the wafer to be developed is baked for a second preset time, wherein the second preset baking temperature is greater than the first preset baking temperature and the second preset baking distance is less than the first preset baking distance.

[0012] The wafer to be developed is baked for a third preset time according to a third preset baking temperature and a third preset baking distance. The third preset baking temperature is less than the first preset baking temperature, and the third preset baking distance is greater than the first preset baking distance.

[0013] In one feasible implementation, a developing process is performed on the aforementioned wafer to be developed, including:

[0014] Adjust the ambient pressure of the environment where the wafer to be developed is located to a preset pressure, wherein the preset pressure is greater than or equal to 50 Pa and less than or equal to 100 Pa.

[0015] Based on the wafer radius of the wafer to be developed, the developing spray radius of the wafer to be developed is determined, wherein the developing spray radius is greater than or equal to 0.2 times the wafer radius and less than or equal to 0.8 times the wafer radius.

[0016] The development spray range is determined based on the wafer center position and the development spray radius.

[0017] Based on the aforementioned developing spray range, the aforementioned wafer to be developed is subjected to preliminary developing treatment;

[0018] Based on the aforementioned developing spray range, the wafer to be developed is subjected to advanced developing treatment.

[0019] In one feasible implementation, the wafer to be developed is subjected to preliminary developing treatment according to the aforementioned developing spray range, including:

[0020] The development of the wafer is controlled according to the first wafer rotation speed and the first rotation duration. The first wafer rotation speed is greater than or equal to 180 rpm and less than or equal to 220 rpm, and the first rotation duration is less than or equal to 5 s.

[0021] Adjust the rotation speed of the wafer to be developed to the second wafer rotation speed, wherein the second wafer rotation speed is greater than or equal to 20 rpm and less than or equal to 150 rpm;

[0022] According to the first spraying duration, the spraying robotic arm is controlled to spray the developing solution toward the center of the wafer. The first spraying duration is greater than or equal to 3s and less than or equal to 15s.

[0023] The robotic arm is controlled to move from the center of the wafer to the spray boundary to perform a preliminary scanning spray of the developing solution on the wafer to be developed. The distance from the spray boundary to the center of the wafer is equal to the developing spray radius.

[0024] When the aforementioned spraying robotic arm moves to the aforementioned spraying boundary position, the aforementioned spraying robotic arm is controlled to spray the aforementioned developing solution to the aforementioned spraying boundary position according to the second spraying duration, wherein the aforementioned second spraying duration is greater than or equal to 2s and less than or equal to 5s.

[0025] The time to be developed is controlled according to the settling time, which is greater than or equal to 2s and less than or equal to 10s.

[0026] The rotation of the wafer to be developed is controlled according to the third wafer rotation speed and the second rotation duration. The third wafer rotation speed is greater than or equal to 300 rpm and less than or equal to 800 rpm, and the second rotation duration is greater than or equal to 10 s and less than or equal to 30 s.

[0027] In one feasible implementation, the wafer to be developed is subjected to a mold development process according to the aforementioned developing spray range, including:

[0028] Adjust the rotation speed of the wafer to be developed to the fourth wafer rotation speed, wherein the fourth wafer rotation speed is greater than or equal to 10 rpm and less than or equal to 80 rpm;

[0029] The spraying robotic arm is repeatedly controlled to move from the center position of the wafer to the spraying boundary position to perform the first scan spray of developer on the wafer to be developed multiple times. The distance from the spraying boundary position to the center position of the wafer is equal to the developing spray radius. The execution time of the first scan spray is greater than or equal to 1 second and less than or equal to 20 seconds. The number of first scan sprays is less than or equal to 5 times.

[0030] Adjust the rotation speed of the wafer to be developed to the fifth wafer rotation speed, which is greater than or equal to 5 rpm and less than or equal to 30 rpm.

[0031] The spraying robotic arm is repeatedly controlled to move from the spraying boundary position to the wafer center position to perform a second scan spray of developer solution on the wafer to be developed multiple times. The execution time of a single second scan spray is greater than or equal to 10s and less than or equal to 40s, and the number of second scan sprays is greater than or equal to 3 times and less than or equal to 10 times.

[0032] The rotation of the wafer to be developed is controlled according to the sixth wafer rotation speed and the third rotation duration. The sixth wafer rotation speed is greater than or equal to 5 rpm and less than or equal to 20 rpm, and the third rotation duration is greater than or equal to 20 s and less than or equal to 60 s.

[0033] The rotation of the wafer to be developed is controlled according to the seventh wafer rotation speed and the fourth rotation duration. The seventh wafer rotation speed is greater than or equal to 200 rpm and less than or equal to 600 rpm, and the fourth rotation duration is greater than or equal to 5s and less than or equal to 10s.

[0034] In one feasible implementation, the above-mentioned photoresist development method further includes:

[0035] The above-mentioned mold development process is repeated on the wafer to be developed, and the number of repetitions is greater than or equal to 3 times and less than or equal to 5 times.

[0036] In one feasible implementation, the above-described photoresist development method further includes:

[0037] The wafers to be developed were then washed with pure water.

[0038] In one feasible implementation, the above-described photoresist development method further includes:

[0039] The wafers to be developed are then subjected to spin drying.

[0040] In one feasible implementation, the wafer to be developed is exposed according to the thickness of the photoresist film, including:

[0041] Based on the thickness of the photoresist film, determine the exposure energy density;

[0042] Based on the aforementioned exposure energy density, the wafer to be developed is subjected to exposure processing.

[0043] In one feasible implementation, the above-described photoresist development method further includes:

[0044] The time difference between acquiring the wafer to be developed and completing the coating process on the wafer is less than or equal to 5 hours.

[0045] Compared with the prior art, the present invention has at least the following beneficial effects: An embodiment of this application provides a photoresist development method, the method comprising: obtaining a wafer to be developed, wherein the wafer to be developed is a wafer having a photoresist film; exposing the wafer to be developed according to the thickness of the photoresist film; baking the wafer to be developed according to a preset baking temperature and a preset baking distance, wherein the preset baking temperature first increases and then decreases with baking time, and the preset baking distance first decreases and then increases with baking time; and performing a development process on the wafer to be developed. The photoresist development method provided in this application improves the heating mode of the wafer after exposure by performing post-exposure baking treatment on the exposed wafer according to a preset baking temperature and a preset baking distance. This prevents the photoresist film on the wafer from being overheated and avoids local over-baking or under-baking of the photoresist film, thereby improving the baking effect on the photoresist film and reducing the possibility of uneven thickness or defects such as wrinkles and bubbles in the photoresist film. Furthermore, in the subsequent development process, when the photoresist film is a positive photoresist, it can help avoid excessive film flow rate in non-exposed areas and prevent large deformation of the photoresist film, reducing the possibility of image distortion and providing a reliable guarantee for the resolution of the developed image. Attached Figure Description

[0046] Various other advantages and benefits will become apparent to those skilled in the art upon reading the following detailed description of exemplary embodiments. The accompanying drawings are for illustrative purposes only and are not intended to limit the scope of this application. Furthermore, the same reference numerals denote the same parts throughout the drawings. In the drawings:

[0047] Figure 1 A schematic flowchart of a photoresist development method according to an embodiment of this application;

[0048] Figure 2 A schematic diagram showing the positional relationship between the wafer to be developed and the wafer hot plate, provided in this application, according to one embodiment;

[0049] Figure 3 A schematic line graph illustrating the change of preset baking temperature with baking time in one embodiment of this application;

[0050] Figure 4 A schematic line graph illustrating the change of preset baking distance with baking time in one embodiment of this application. Detailed Implementation

[0051] Exemplary embodiments of the present application will now be described in more detail with reference to the accompanying drawings. While exemplary embodiments of the present application are shown in the drawings, it should be understood that the present application may be implemented in various forms and should not be limited to the embodiments set forth herein. Rather, these embodiments are provided so that this application will be thorough and complete, and will fully convey the scope of the present application to those skilled in the art.

[0052] According to embodiments of this application, a photoresist development method is proposed, such as... Figure 1 As shown, the method may include:

[0053] Step S110: Obtain the wafer to be developed, which is a wafer with a photoresist film;

[0054] It is understood that a wafer is a silicon wafer used to fabricate silicon semiconductor circuits. Its raw material is silicon. Because of its circular shape, it is called a wafer. Development is a photolithography technique in which the photoresist in the exposure area of ​​positive photoresist and the non-exposure area of ​​negative photoresist are dissolved in a developing solution to form a three-dimensional pattern on the photoresist. The wafer to be developed refers to a wafer with a photoresist film formed on its surface. For example, the aforementioned photoresist film can be a positive photoresist film. It is understood that positive photoresist is widely used in current production due to its good contrast and resolution.

[0055] Step S120: Expose the wafer to be developed according to the thickness of the photoresist film;

[0056] Understandably, in photolithography, exposure refers to the process of using ultraviolet light sources, such as mercury lamps, to irradiate the wafer to be developed through a photomask, causing a photochemical reaction in the photoresist and transferring the pattern from the photomask to the photoresist on the wafer. The photoresist film is further divided into exposed and unexposed areas based on whether the area is illuminated by the light source. Understandably, during the exposure process of the wafer, the process parameters can be controlled according to the thickness of the photoresist film on the wafer to ensure the optimal exposure effect. These process parameters include, but are not limited to, exposure energy density.

[0057] It should be noted that the photoresist film on the wafer to be developed can be divided into exposed areas and non-exposed areas. The exposed areas refer to the areas that have been illuminated by the light source, while the non-exposed areas refer to the areas that have not been illuminated by the light source.

[0058] Step S130: The wafer to be developed is baked according to the preset baking temperature and preset baking distance. The preset baking temperature first increases and then decreases with the baking time, and the preset baking distance first decreases and then increases with the baking time.

[0059] It is understandable that after exposing the wafer to be developed, a baking process can be performed on the exposed wafer according to a preset baking temperature and a preset baking distance. This promotes the photochemical reaction of the photoresist film on the wafer, enhances the sufficiency of the aforementioned photochemical reaction, and alters the solubility of the photoresist material relative to the developer, thereby facilitating pattern formation in subsequent development processes and improving the development effect of the photoresist. During the baking process after exposure, the preset baking temperature and preset baking distance are controlled. Specifically, the preset baking temperature is controlled to first increase and then decrease with baking time, and the preset baking distance is controlled to first decrease and then increase with baking time. This improves the heating mode of the photoresist film. It is understood that, based on the control of the preset baking temperature, the photoresist film can be altered. The heat absorption of the photoresist film, thus preventing excessive or insufficient heat absorption, helps to promote a more complete photochemical reaction while reducing excessive diffusion of photoacids, ensuring the pattern quality of the photoresist. Correspondingly, based on the control of the preset baking distance, the heat received by different areas of the photoresist film can be changed, reducing the possibility of over-baking or under-baking in different areas of the photoresist film, thereby improving the baking effect of the photoresist film and reducing the possibility of uneven thickness or defects such as wrinkles and bubbles. Furthermore, in the subsequent development process, when the photoresist film is positive, it can help avoid excessive film flow rate in non-exposed areas and prevent large deformation of the photoresist film, reducing the possibility of image distortion and providing a reliable guarantee for the resolution of the developed image.

[0060] For example, such as Figure 2 As shown, the aforementioned preset baking distance refers to the interval between the wafer 100 to be developed and the wafer hot plate 200. During the baking process, the photoresist film 110 of the wafer 100 to be developed is arranged away from the wafer hot plate 200. It should be noted that... Figure 2 The middle region A is used to represent the exposure area of ​​the wafer to be developed, and the dimension line h is used to represent the preset baking distance mentioned above.

[0061] For example, the preset baking distance h can be negatively correlated with the preset baking temperature. Thus, during the baking process after exposure, when the preset baking temperature is high, the wafer 100 to be developed can be baked at a larger preset baking distance h. Correspondingly, when the preset baking temperature is low, the wafer 100 to be developed can be baked at a smaller preset baking distance h. This avoids the portion of the photoresist film 110 close to the wafer hot plate 200 being intensely heated, which would cause the difference in heat absorption of the photoresist material at different positions along the thickness direction of the photoresist film 110 to accumulate rapidly and form an excessively large difference in baking effect. This further improves the baking effect of the wafer 100 to be developed, which is beneficial to improve the thickness uniformity of the photoresist film after baking, reduces the possibility of wrinkles and bubbles appearing in the photoresist film after baking, provides favorable conditions for subsequent development processing, and improves the development effect of the photoresist.

[0062] For example, the preset baking temperature can be greater than or equal to 50°C and less than or equal to 130°C; the preset baking distance can be greater than or equal to 0 and less than or equal to 10μm.

[0063] It should be noted that in the field of MEMS (Micro-Electro-Mechanical Systems), the thickness of photoresist films is typically between a few micrometers and several hundred micrometers, which is usually quite large. In traditional technology, constant temperature and distance baking is often used when baking the wafer after exposure. Constant temperature and distance baking often produces good baking results for thin-film wafers. It is understood that the thickness of the photoresist film on the aforementioned thin-film wafers is typically between several hundred angstroms and tens of thousands of angstroms. However, for the thick-film wafers used in MEMS, constant temperature and distance baking can easily cause large differences in the heating conditions between different areas of the photoresist film, which can easily lead to over-baking or under-baking of some areas of the photoresist film, which is not conducive to the development process of the wafer. Therefore, compared with the baking method in traditional technology, the photoresist development method provided in this application embodiment, based on the aforementioned post-exposure baking execution method, can improve the heating method of the wafer to be developed, thereby preventing the photoresist film on the wafer to be developed from being overheated, avoiding local over-baking or under-baking of the photoresist film, improving the baking effect of the photoresist film, reducing the possibility of uneven thickness or defects such as wrinkles and bubbles in the photoresist film, and in the subsequent development process, when the photoresist film is a positive photoresist, it can help avoid excessive film flow rate in non-exposed areas and prevent the photoresist film from undergoing large deformation, reducing the possibility of image distortion and providing a reliable guarantee for the resolution of the developed image.

[0064] Step S140: Perform a developing process on the above-mentioned wafer to be developed.

[0065] It is understandable that the developing process in existing industrial processes usually includes pre-spraying, developing spraying, and surface dwell of the developing solution. Based on the aforementioned baking treatment of the wafer after exposure, the baking effect of the wafer to be developed can be improved, thereby creating favorable conditions for the execution of the developing process. This helps to reduce photoresist residue during the developing process. When the photoresist material of the photoresist film is positive photoresist, it reduces the film flow rate in the non-exposed area of ​​the wafer to be developed and improves the resolution of the developed image.

[0066] In one feasible embodiment, the wafer to be developed is baked according to a preset baking temperature and a preset baking distance, including:

[0067] The wafer to be developed is baked for a first preset time based on a first preset baking temperature and a first preset baking distance.

[0068] Based on the second preset baking temperature and the second preset baking distance, the wafer to be developed is baked for a second preset time, wherein the second preset baking temperature is greater than the first preset baking temperature and the second preset baking distance is less than the first preset baking distance.

[0069] The wafer to be developed is baked for a third preset time according to a third preset baking temperature and a third preset baking distance. The third preset baking temperature is less than the first preset baking temperature, and the third preset baking distance is greater than the first preset baking distance.

[0070] In this technical solution, during the baking process of the wafer to be developed according to a preset baking temperature and a preset baking distance, the baking process can be divided into three stages. The preset baking temperature and preset baking distance differ in each stage, resulting in a phased change in the preset baking temperature and preset baking distance over time. The baking times for the three stages can be a first preset time, a second preset time, and a third preset time, respectively. These preset times can be equal or unequal; no specific limitations are imposed here. In the first stage, the wafer to be developed can be baked according to the first preset baking temperature and the first preset baking distance for the duration of the first preset time. It is understood that, since the second preset baking temperature is higher than the first preset baking temperature and the third preset baking temperature is lower than the first preset baking temperature, the first preset baking temperature is at a relatively moderate position between the first and third preset baking temperatures. Correspondingly, the first preset baking distance is also at a relatively moderate position between the first and third preset baking distances. Therefore, in the first stage, the wafer to be developed can be baked at a relatively moderate baking temperature and baking distance, so that the wafer is heated more uniformly and comprehensively, thereby promoting the photoresist material at different locations on the photoresist film. Photochemical reaction improves the solubility of photoresist material relative to developer; in the second stage, the wafer to be developed can be baked according to the second preset baking temperature and the second preset baking distance, for a duration of the second preset time. The second preset baking temperature is relatively high, and the second preset baking distance is relatively short. Therefore, in the second stage, the wafer to be developed can be baked with higher heating efficiency. This is beneficial to improving the baking efficiency of the wafer to be developed and shortening the baking process. On the other hand, it can further remove the standing wave effect in the photoresist film in the second stage, which is beneficial to improving the resolution of the photoresist developed image; in the third stage, according to the third preset... The wafer to be developed is baked at a set baking temperature and a third preset baking distance for a duration equal to the third preset time. The third preset baking temperature is relatively low, and the third preset baking distance is relatively large. Thus, in the third stage, the wafer to be developed can be baked more gently. This avoids over-baking of the photoresist film at high temperatures, prevents the rapid accumulation of heat differences in the photoresist material at different locations on the photoresist film, and avoids excessive differences in baking effect. This is beneficial to improving the thickness uniformity of the photoresist film after baking, reducing the possibility of wrinkles and bubbles after baking, providing favorable conditions for subsequent development processing, and improving the development effect of the photoresist.

[0071] It is understood that the baking process of the wafer to be developed, based on the preset baking temperature and preset baking distance, includes, but is not limited to, the three stages mentioned above. There may also be an adjustment stage between adjacent stages, such as heating up and lowering the distance or lowering the distance.

[0072] For ease of explanation, during the baking process of the aforementioned wafer to be developed according to the preset baking temperature and preset baking distance, the changes of the preset baking temperature and preset baking time can be respectively as follows: Figure 3 and Figure 4 As shown, Figure 3 In the above process, 0-1 min represents the preparation stage of the post-baking process; 1-5 min represents the first stage, during which the first preset baking temperature is 60℃ and the first preset duration is 4 min; 5 min-6 min represents the stage of heating the wafer hot plate; 6 min-9 min represents the second stage, during which the second preset baking temperature is 90℃ and the second preset duration is 3 min; 9 min-10 min represents the stage of cooling the wafer hot plate; and 10 min-13 min represents the third stage, during which the third preset baking temperature is 50℃ and the third preset duration is 3 min. Figure 4 In the above process, 0-1 min represents the preparation stage of the post-baking process; 1-5 min represents the first stage, during which the first preset baking distance is 2 μm and the first preset duration is 4 min; 5 min-6 min represents the stage of reducing the baking distance; 6 min-9 min represents the second stage, during which the second preset baking distance is 1 μm and the second preset duration is 3 min; 9 min-10 min represents the stage of increasing the baking distance; and 10 min-13 min represents the third stage, during which the third preset baking distance is 3 μm and the second preset duration is 4 min.

[0073] It should be noted that the examples given above are only for the purpose of understanding the method given in this embodiment and are not unique. The specific values ​​of each stage should be determined according to the actual situation, ensuring that the third preset baking temperature is lower than the first preset baking temperature, the second preset baking temperature is higher than the first preset baking temperature, and the third preset baking distance is greater than the first preset baking distance and the second preset baking distance is less than the first preset baking distance.

[0074] The post-baking process for the wafer to be developed, as described in the above embodiments, promotes the photochemical reaction of the photoresist film, more thoroughly eliminates the standing wave effect, avoids the photoresist material of the photoresist film from affecting the subsequent reaction with the developing solution due to excessive high-temperature baking, reduces the residue of developed photoresist, and improves the resolution of the developed image.

[0075] In one feasible embodiment, a developing process is performed on the wafer to be developed, including:

[0076] Adjust the ambient pressure of the environment where the wafer to be developed is located to a preset pressure, wherein the preset pressure is greater than or equal to 50 Pa and less than or equal to 100 Pa.

[0077] Based on the wafer radius of the wafer to be developed, the developing spray radius of the wafer to be developed is determined, wherein the developing spray radius is greater than or equal to 0.2 times the wafer radius and less than or equal to 0.8 times the wafer radius.

[0078] The development spray range is determined based on the wafer center position and the development spray radius.

[0079] Based on the aforementioned developing spray range, the aforementioned wafer to be developed is subjected to preliminary developing treatment;

[0080] Based on the aforementioned developing spray range, the wafer to be developed is subjected to advanced developing treatment.

[0081] In this technical solution, after performing the post-baking process on the wafer to be developed, the solution performs a developing process on the wafer. First, the ambient pressure of the working environment where the wafer to be developed is located is adjusted to the preset pressure. The working environment can be a cavity environment, and the preset pressure is 50Pa to 100Pa. It is understood that the cavity can be equipped with an automatic valve to automatically adjust the internal pressure of the cavity. Therefore, in practical applications, pressure adjustment can be achieved by operating the automatic valve.

[0082] It is understood that the range of the developing spray radius is determined based on the wafer radius of the wafer to be developed, and the developing spray radius is between 0.2 times and 0.8 times the wafer radius. When spraying the same amount of developer, compared to concentrating the developer spray on the center of the wafer, spraying the wafer according to the developing spray radius avoids excessive concentration of developer in the center of the wafer, which helps improve the uniformity of developer distribution on the wafer surface, prevents over-development in the center of the wafer, provides further assurance for improving the developing effect, and helps improve the resolution of the developed image.

[0083] Furthermore, the development spray range can be determined by the center position of the wafer and the development spray radius. It is understood that during the development process, the wafer to be developed typically rotates at a certain speed. Therefore, the development spray range can be a circular area with the wafer center as the center and the development spray radius as the radius. Thus, by determining the development spray range, the wafer to be developed can undergo preliminary development and advanced development processes. Spraying the developing solution onto the wafer to be developed according to the development spray range allows the developing solution to be distributed more evenly on the photoresist film, facilitating contact between the photoresist film and the developing solution, reducing photoresist residue, and improving the resolution of the developed image.

[0084] In one feasible embodiment, the wafer to be developed is subjected to preliminary developing treatment according to the aforementioned developing spray range, including:

[0085] The development of the wafer is controlled according to the first wafer rotation speed and the first rotation duration. The first wafer rotation speed is greater than or equal to 180 rpm and less than or equal to 220 rpm, and the first rotation duration is less than or equal to 5 s.

[0086] Adjust the rotation speed of the wafer to be developed to the second wafer rotation speed, wherein the second wafer rotation speed is greater than or equal to 20 rpm and less than or equal to 150 rpm;

[0087] According to the first spraying duration, the spraying robotic arm is controlled to spray the developing solution toward the center of the wafer. The first spraying duration is greater than or equal to 3s and less than or equal to 15s.

[0088] The robotic arm is controlled to move from the center of the wafer to the spray boundary to perform a preliminary scanning spray of the developing solution on the wafer to be developed. The distance from the spray boundary to the center of the wafer is equal to the developing spray radius.

[0089] When the aforementioned spraying robotic arm moves to the aforementioned spraying boundary position, the aforementioned spraying robotic arm is controlled to spray the aforementioned developing solution to the aforementioned spraying boundary position according to the second spraying duration, wherein the aforementioned second spraying duration is greater than or equal to 2s and less than or equal to 5s.

[0090] The time to be developed is controlled according to the settling time, which is greater than or equal to 2s and less than or equal to 10s.

[0091] The rotation of the wafer to be developed is controlled according to the third wafer rotation speed and the second rotation duration. The third wafer rotation speed is greater than or equal to 300 rpm and less than or equal to 800 rpm, and the second rotation duration is greater than or equal to 10 s and less than or equal to 30 s.

[0092] In this technical solution, during the preliminary developing process of the wafer to be developed according to the aforementioned developing spray range, the wafer to be developed can be controlled to rotate at the aforementioned first wafer rotation speed for a duration of the aforementioned first time period, which is less than or equal to 5 seconds. During the developing process, the wafer to be developed typically needs to have a certain rotation speed. This speed control allows the wafer to have a certain initial velocity before the developer is sprayed, avoiding significant adjustments to the wafer's rotation speed during spraying. This prevents a large sudden change in the centrifugal force on the developer, thereby increasing the contact time between the developer and the wafer and reducing developer waste. Furthermore, if the wafer to be developed becomes contaminated with dust, particles, or other adhering substances during transfer, the centrifugal force provided by the higher rotation speed can remove these adhering substances, improving the surface cleanliness of the wafer.

[0093] Then, the rotation speed of the wafer to be developed can be controlled to continuously rotate at the second wafer rotation speed, which is greater than or equal to 20 rpm and less than or equal to 150 rpm. At the same time, the spraying robot arm is controlled to spray the developer solution from the center position of the wafer for a duration of the first spraying time, which is greater than or equal to 3 seconds and less than or equal to 15 seconds. This avoids spraying the center position of the wafer with developer solution for a long time, thus preventing the problem of over-development of the wafer center and affecting the image imaging effect.

[0094] Subsequently, the spraying robotic arm can be controlled to move from the center of the wafer to the spraying boundary position. During the movement, the spraying robotic arm continuously sprays the developing solution to form a developing solution scanning spray on the wafer to be developed. The distance from the spraying boundary position to the center of the wafer is equal to the developing spray radius. In conjunction with the rotation of the wafer to be developed, the spraying robotic arm can spray the developing solution on the wafer to be developed within the developing spray range. This prevents overdevelopment at the center of the wafer while expanding the spray range of the developing solution, thereby increasing the effective range of the developing solution on the wafer to be developed and improving the developing effect.

[0095] When the spraying robot arm moves to the spraying boundary position, the spraying robot arm can be controlled to maintain the second spraying duration at the spraying boundary position. The second spraying duration is 2s to 5s, during which the developing solution is continuously sprayed onto the spraying boundary position, which is beneficial for developing the Trench structure on the photoresist film, thereby further improving the developing effect of the wafer to be developed.

[0096] After the second spraying time, the spraying robot arm can be controlled to stop spraying and the rotation of the wafer to be developed can be stopped. The wafer to be developed can be kept still according to the settling time, which is 2 to 10 seconds, so that the developer can react fully with the photoresist film and ensure the development effect.

[0097] After the wafer to be developed has been allowed to stand, it can be controlled to rotate at the third wafer speed and the second rotation duration. The third wafer speed is 300 rpm to 800 rpm, and the second rotation duration is...

[0098] The rotation time is 10s to 30s to complete the initial development process of the wafer to be developed. The high-speed rotation motion removes the impurities caused by the reaction between the developer and the photoresist in the exposed area, and develops the image to facilitate subsequent advanced development of the wafer.

[0099] In one feasible embodiment, the wafer to be developed is subjected to advanced development processing according to the aforementioned development spray range, including:

[0100] Adjust the rotation speed of the wafer to be developed to the fourth wafer rotation speed, wherein the fourth wafer rotation speed is greater than or equal to 10 rpm and less than or equal to 80 rpm;

[0101] The spraying robotic arm is repeatedly controlled to move from the center position of the wafer to the spraying boundary position to perform the first scan spray of developer on the wafer to be developed multiple times. The distance from the spraying boundary position to the center position of the wafer is equal to the developing spray radius. The execution time of the first scan spray is greater than or equal to 1 second and less than or equal to 20 seconds. The number of first scan sprays is less than or equal to 5 times.

[0102] Adjust the rotation speed of the wafer to be developed to the fifth wafer rotation speed, which is greater than or equal to 5 rpm and less than or equal to 30 rpm.

[0103] The spraying robotic arm is repeatedly controlled to move from the spraying boundary position to the wafer center position to perform a second scan spray of developer solution on the wafer to be developed multiple times. The execution time of a single second scan spray is greater than or equal to 10s and less than or equal to 40s, and the number of second scan sprays is greater than or equal to 3 times and less than or equal to 10 times.

[0104] The rotation of the wafer to be developed is controlled according to the sixth wafer rotation speed and the third rotation duration. The sixth wafer rotation speed is greater than or equal to 5 rpm and less than or equal to 20 rpm, and the second rotation duration is greater than or equal to 20 s and less than or equal to 60 s.

[0105] The rotation of the wafer to be developed is controlled according to the seventh wafer rotation speed and the fourth rotation duration. The seventh wafer rotation speed is greater than or equal to 200 rpm and less than or equal to 600 rpm, and the fourth rotation duration is greater than or equal to 5s and less than or equal to 10s.

[0106] In this technical solution, after the wafer to be developed undergoes the aforementioned preliminary developing process, a progressive developing process can be performed. The spraying robotic arm can be adjusted to move from the center of the wafer to the spraying boundary position in a first scanning spray manner. The first scanning spray is executed less than or equal to 5 times, and the duration of each first scanning spray is between 1 second and 20 seconds. It can be understood that the first scanning spray is the continuous spraying of developing solution onto the wafer to be developed during the process of controlling the spraying robotic arm to move from the center of the wafer to the spraying boundary position. During the repeated execution of the first scanning spray, the wafer to be developed is controlled to rotate at a fourth wafer speed, which is between 10 rpm and 80 rpm. It can be understood that controlling the wafer to be developed to rotate at a relatively low speed is to avoid the developer being thrown off the wafer due to excessive rotation speed during the scanning spray, resulting in too short a contact time between the developer and the photoresist film. This facilitates a more complete reaction between the developer and the photoresist material in the photoresist film, reduces photoresist residue, and ensures the resolution of the developed image.

[0107] Then, the spraying robotic arm is adjusted to move from the spraying boundary position to the wafer center position in a second scanning spray manner. The second scanning spray is executed more than or equal to 3 times and less than or equal to 10 times. The execution time of a single second scanning spray is between 10 seconds and 40 seconds. It can be understood that the second scanning spray is the process of continuously spraying developer onto the wafer to be developed while controlling the spraying robotic arm to move from the spraying boundary position to the wafer center position. During the multiple executions of the second scanning spray, this method controls the wafer to be developed to rotate at a fifth wafer rotation speed, which is between 5 rpm and 30 rpm.

[0108] By performing the aforementioned scanning spraying method multiple times while controlling the wafer to be developed to rotate at a relatively low speed, the developer can make full contact with the photoresist deep in the photoresist trench structure of the exposed area, promoting the reaction between the photoresist and the developer, reducing the residue of the developed photoresist, and improving the resolution of the developed image.

[0109] Subsequently, the spraying robotic arm can be controlled to stop spraying, and the wafer to be developed can be adjusted to rotate at the sixth wafer speed and the third rotation duration. The sixth wafer speed is 5 rpm to 20 rpm, and the third rotation duration is 20 s to 60 s. After multiple scanning sprays, controlling the wafer to be developed to rotate continuously at a relatively slow speed for a relatively long time allows the developer to make full contact with the photoresist deep in the photoresist trenches of the exposure area, promoting the reaction between the photoresist and the developer, reducing the residue of the developed photoresist, and improving the resolution of the developed image.

[0110] After the third rotation duration, the wafer to be developed can be controlled to rotate at the seventh wafer speed and the fourth rotation duration. The seventh wafer speed is 200 rpm to 600 rpm, and the fourth rotation duration is 5 s to 10 s to complete the mold development process. The high-speed rotation motion removes the impurities that react with the photoresist in the exposure area after the developer is applied, which helps to improve the surface cleanliness of the wafer to be developed after the mold development.

[0111] In one feasible embodiment, the above-described photoresist development method further includes:

[0112] The above-mentioned mold development process is repeated on the wafer to be developed, and the number of repetitions is greater than or equal to 3 times and less than or equal to 5 times.

[0113] In this technical solution, the aforementioned advanced development process can be repeated 3 to 5 times. The number of repetitions can be selected based on the thickness of the photoresist film. That is, the greater the thickness of the photoresist film, the more repetitions can be performed. Through multiple advanced development processes, the photoresist in the exposed area of ​​the wafer to be developed, especially the photoresist deep in the trench structure, can react more fully with the developer, reducing photoresist residue. At the same time, it reduces the damage of the developer to the photoresist film in the non-exposed area and reduces the film flow rate of the photoresist film in the non-exposed area.

[0114] In some feasible examples, when the above-mentioned advanced development process is repeatedly performed on the wafer to be developed, the rotational speed of each wafer in each advanced development process is 1.05 to 1.15 times that of the corresponding wafer in the previous advanced development process.

[0115] To facilitate the explanation of the above embodiments, an example is given. If the photoresist film thickness requires four pre-development processes, and in the first pre-development process, the fourth, fifth, sixth, and seventh wafer rotation speeds are 20 rpm, 25 rpm, 25 rpm, and 300 rpm respectively, then in the second pre-development process, the fourth, fifth, sixth, and seventh wafer rotation speeds can be adjusted. The rotation speeds of the fourth, fifth, sixth, and seventh wafers of the wafer to be developed can be adjusted to 25 rpm, 29 rpm, 29 rpm, and 360 rpm during the third die-developing process, and to 22 rpm, 28 rpm, 28 rpm, and 330 rpm during the fourth die-developing process, and to 28 rpm, 32 rpm, 32 rpm, and 400 rpm during the fourth die-developing process.

[0116] In one feasible embodiment, the above-described photoresist development method further includes:

[0117] The wafers to be developed were then washed with pure water.

[0118] In this technical solution, after the wafer to be developed undergoes the above-mentioned advanced development process, the wafer to be developed can be cleaned with pure water, where pure water refers to deionized water, to wash away defective particles after development and improve the clarity of the developed image.

[0119] For example, in the above-mentioned pure water washing process, the wafer can first be controlled to rotate at a speed of 200 rpm to 500 rpm. At this time, the cleaning robot arm is controlled to move from the initial position to the center position of the wafer. During this period, the pure water is sprayed. Then, the cleaning robot arm is controlled to move from the center of the wafer to the spray boundary position. During this period, the pure water is sprayed in a scanning spraying manner. This process is repeated multiple times. Then, the cleaning robot arm is controlled to stop spraying the pure water, so as to wash away the defective particles after development to a great extent and improve the resolution of the developed image.

[0120] In one feasible embodiment, the above-described photoresist development method further includes:

[0121] The wafers to be developed are then subjected to spin drying.

[0122] In this technical solution, after the wafer to be developed is treated with pure water, it can be further dried by spin drying to keep the wafer dry.

[0123] For example, when performing spin drying on the wafer to be developed, the rotation speed of the wafer to be developed can be increased to 2000 rpm to 2500 rpm for 15 s to 40 s. This step can spin dry the pure water remaining in the pure water washing process, thereby improving the surface dryness and cleanliness of the wafer to be developed.

[0124] In one feasible embodiment, the wafer to be developed is exposed according to the thickness of the photoresist film, including:

[0125] Based on the thickness of the photoresist film, determine the exposure energy density;

[0126] Based on the aforementioned exposure energy density, the wafer to be developed is subjected to exposure processing.

[0127] It is understandable that photoresist films vary in thickness, and lasers or ultraviolet light are often used for exposure during the exposure process. The shorter the wavelength, the stronger the penetration and the greater the energy of the photons. For the aforementioned photoresist film, the greater the thickness, the shorter the wavelength of the light wave required, and the greater the exposure energy density required for the wafer to be developed. In this technical solution, the exposure energy density is determined by the thickness of the photoresist film, which can effectively promote the photochemical reaction of the photoresist during exposure and improve the integrity of the developed image.

[0128] In one feasible embodiment, the above-described photoresist development method further includes:

[0129] The time difference between acquiring the wafer to be developed and completing the coating process on the wafer is less than or equal to 5 hours.

[0130] In this technical solution, when acquiring the wafer to be developed, the wafer to be developed can be selected within 5 hours from the time of acquisition to the time of photoresist coating completion as the development treatment object. It can be understood that the aforementioned acquisition time is the time when the wafer to be developed is acquired, and the aforementioned photoresist coating completion time is the time when the wafer to be developed completes the photoresist coating. This can avoid the properties of the photoresist film on the wafer to be developed from changing during subsequent development treatment, and ensure the development treatment effect of the wafer to be developed.

[0131] In summary, this invention provides a photoresist development method, comprising: obtaining a wafer to be developed, wherein the wafer to be developed is a wafer having a photoresist film; exposing the wafer to be developed according to the thickness of the photoresist film; baking the wafer to be developed according to a preset baking temperature and a preset baking distance, wherein the preset baking temperature first increases and then decreases with baking time, and the preset baking distance first decreases and then increases with baking time; and performing a development process on the wafer to be developed. The photoresist development method provided in this application improves the heating mode of the wafer after exposure by performing post-exposure baking treatment on the exposed wafer according to a preset baking temperature and a preset baking distance. This prevents the photoresist film on the wafer from being overheated and avoids local over-baking or under-baking of the photoresist film, thereby improving the baking effect on the photoresist film and reducing the possibility of uneven thickness or defects such as wrinkles and bubbles in the photoresist film. Furthermore, in the subsequent development process, when the photoresist film is a positive photoresist, it can help avoid excessive film flow rate in non-exposed areas and prevent large deformation of the photoresist film, reducing the possibility of image distortion and providing a reliable guarantee for the resolution of the developed image.

[0132] In this application, relational terms such as "first" and "second" are used merely to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitation, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes the aforementioned element. The term "two or more" includes two or more cases.

[0133] Obviously, those skilled in the art can make various modifications and variations to this specification without departing from its spirit and scope. Therefore, if such modifications and variations fall within the scope of the claims and their equivalents, this specification is also intended to include such modifications and variations.

Claims

1. A method for developing positive photoresist, wherein the photoresist is a thick photoresist, characterized in that, include: Obtain a wafer to be developed, wherein the wafer to be developed is a wafer with a photoresist film; The wafer to be developed is exposed according to the thickness of the photoresist film; The wafer to be developed is baked according to a preset baking temperature and a preset baking distance. The preset baking temperature first increases and then decreases with the baking time, and the preset baking distance first decreases and then increases with the baking time. Performing a developing process on the wafer to be developed includes: The wafer to be developed is subjected to preliminary development treatment according to the development spray range; According to the development spray range, the wafer to be developed is subjected to advanced development processing, including: Adjust the rotation speed of the wafer to be developed to the fourth wafer rotation speed, wherein the fourth wafer rotation speed is greater than or equal to 10 rpm and less than or equal to 80 rpm; The spraying robotic arm is controlled to move from the center of the wafer to the spraying boundary multiple times to perform the first scan spray of developer on the wafer to be developed multiple times. The distance from the spraying boundary to the center of the wafer is equal to the developing spray radius. The execution time of the first scan spray is greater than or equal to 1 second and less than or equal to 20 seconds. The number of the first scan spray is less than or equal to 5 times. Adjust the rotation speed of the wafer to be developed to the fifth wafer rotation speed, wherein the fifth wafer rotation speed is greater than or equal to 5 rpm and less than or equal to 30 rpm; The spraying robotic arm is repeatedly controlled to move from the spraying boundary position to the center position of the wafer to be developed, so as to perform a second scan spray of developer solution on the wafer to be developed multiple times. The execution time of a single second scan spray is greater than or equal to 10s and less than or equal to 40s, and the number of second scan sprays is greater than or equal to 3 times and less than or equal to 10 times. The development of the wafer is controlled according to the sixth wafer rotation speed and the third rotation duration. The sixth wafer rotation speed is greater than or equal to 5 rpm and less than or equal to 20 rpm, and the third rotation duration is greater than or equal to 20 s and less than or equal to 60 s. The development of the wafer is controlled according to the seventh wafer rotation speed and the fourth rotation duration. The seventh wafer rotation speed is greater than or equal to 200 rpm and less than or equal to 600 rpm, and the fourth rotation duration is greater than or equal to 5s and less than or equal to 10s. Depending on the thickness of the photoresist film, the wafer to be developed is subjected to the advanced development process repeatedly, with the number of repetitions being greater than or equal to 3 and less than or equal to 5, so that the developing solution can make sufficient contact with the photoresist deep in the trench structure of the photoresist film and reduce photoresist residue.

2. The positive photoresist development method according to claim 1, characterized in that, The baking process for the wafer to be developed, based on a preset baking temperature and a preset baking distance, includes: The wafer to be developed is baked for a first preset time based on a first preset baking temperature and a first preset baking distance. The wafer to be developed is baked for a second preset time according to a second preset baking temperature and a second preset baking distance, wherein the second preset baking temperature is greater than the first preset baking temperature and the second preset baking distance is less than the first preset baking distance. The wafer to be developed is baked for a third preset time according to a third preset baking temperature and a third preset baking distance. The third preset baking temperature is less than the first preset baking temperature, and the third preset baking distance is greater than the first preset baking distance.

3. The positive photoresist development method according to claim 1, characterized in that, The developing process performed on the wafer to be developed includes: Adjust the ambient pressure of the environment where the wafer to be developed is located to a preset pressure, wherein the preset pressure is greater than or equal to 50 Pa and less than or equal to 100 Pa; The developing spray radius of the wafer to be developed is determined based on the wafer radius of the wafer to be developed, wherein the developing spray radius is greater than or equal to 0.2 times the wafer radius and less than or equal to 0.8 times the wafer radius; The developing spray range is determined based on the wafer center position of the wafer to be developed and the developing spray radius.

4. The positive photoresist development method according to claim 1, characterized in that, The preliminary developing process of the wafer to be developed according to the developing spray range includes: The development of the wafer is controlled to rotate according to the first wafer rotation speed and the first rotation duration. The first wafer rotation speed is greater than or equal to 180 rpm and less than or equal to 220 rpm, and the first rotation duration is less than or equal to 5 s. Adjust the rotation speed of the wafer to be developed to the second wafer rotation speed, which is greater than or equal to 20 rpm and less than or equal to 150 rpm; According to the first spraying duration, the spraying robot arm is controlled to spray the developing solution toward the center of the wafer. The first spraying duration is greater than or equal to 3s and less than or equal to 15s. The spraying robotic arm is controlled to move from the center of the wafer to the spraying boundary position to perform a preliminary scanning spray of the developing solution on the wafer to be developed. The distance from the spraying boundary position to the center of the wafer is equal to the developing spray radius. When the spraying robotic arm moves to the spraying boundary position, the spraying robotic arm is controlled to spray the developing solution towards the spraying boundary position according to the second spraying duration, wherein the second spraying duration is greater than or equal to 2s and less than or equal to 5s; The time to be developed of the wafer is controlled according to the settling time, wherein the settling time is greater than or equal to 2s and less than or equal to 10s. The development of the wafer is controlled based on the third wafer rotation speed and the second rotation duration. The third wafer rotation speed is greater than or equal to 300 rpm and less than or equal to 800 rpm, and the second rotation duration is greater than or equal to 10 s and less than or equal to 30 s.

5. The positive photoresist development method according to any one of claims 1 to 4, characterized in that, Also includes: The wafer to be developed is washed with pure water.

6. The positive photoresist development method according to claim 5, characterized in that, Also includes: The wafer to be developed is subjected to spin drying.

7. The positive photoresist development method according to any one of claims 1 to 4, characterized in that, The step of exposing the wafer to be developed according to the thickness of the photoresist film includes: The exposure energy density is determined based on the thickness of the photoresist film; The wafer to be developed is exposed according to the exposure energy density.

8. The positive photoresist development method according to any one of claims 1 to 4, characterized in that, The time difference between acquiring the wafer to be developed and completing the coating process on the wafer to be developed is less than or equal to 5 hours.

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