Process method for improving development defect
Through two pre-wetting treatments, a uniform and complete pre-wetting liquid film is formed by rotating at different rotation speeds and times, which solves the development defect problem of highly hydrophobic photoresist, and simplifies the development process and high yield, avoiding additional costs.
Patent Information
- Application Number
- CN202510505861.3
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-04-22
- Publication Date
- 2025-07-18
AI Technical Summary
In the prior art, water droplets are formed on the surface of highly hydrophobic photoresist when pre-wet, resulting in discontinuity of the water film and the developing liquid cannot enter quickly, resulting in incomplete development and developing defects, which affects the performance of semiconductor devices in subsequent processes.
Two pre-wetting treatments are adopted to form a uniform and complete pre-wetting liquid film through three rotational speeds and times. The first pre-wetting treatment improves the wetting properties of the photoresist and pre-wetting liquid, and the second pre-wetting treatment forms a defect-free liquid film to ensure the smooth entry of the developer.
The development defects caused by insufficient pre-wetting are solved, with good process compatibility, low time consumption, no increase in production costs, and no damage to the device, and high overall yield.
Smart Images
Figure CN120335259A_ABST
Abstract
Description
Technical Field
[0001] This application relates to the field of semiconductor technology, and particularly to a process method for improving development defects. Background Art
[0002] The lithography process is an important process in semiconductor manufacturing, usually including multiple processes such as spin coating photoresist, exposure, and development. Among them, the development process is to use a chemical developer to react with the exposed area of the photoresist and then dissolve and remove the photoresist material in this area, ultimately realizing the transfer of the mask pattern.
[0003] In the prior art, the commonly used development process usually includes processes such as DIW (deionized water) pre-wetting, spraying developer and cleaning, and spin-drying. However, considering that the hydrophobicity of the surfaces of different photoresist (PR) materials is different, when pre-wetting by rotation on the surface of highly hydrophobic materials, DIW forms water droplets, resulting in a discontinuous water film, so that the developer (DEV) cannot quickly enter the photoresist on the highly hydrophobic surface, ultimately making the development incomplete and forming defects. The development defects of the photoresist will cause many subsequent processes, such as etching or ion implantation, to produce defects, deteriorating the performance of the formed semiconductor device.
[0004] It should be noted that the above introduction of the technical background is only for the convenience of clearly and completely explaining the technical solution of this application and facilitating the understanding of those skilled in the art. It cannot be considered that the above technical solutions are well-known to those skilled in the art just because these solutions are described in the background art part of this application. Summary of the Invention
[0005] In order to solve the above problems, the following provides a process method for improving development defects, including the following steps: Provide a wafer to be developed, and a photoresist layer is formed on the surface of the wafer; Perform a first pre-wetting treatment on the wafer to form a first pre-wetting liquid film on the surface of the photoresist layer; Perform a second pre-wetting treatment on the wafer to form a second pre-wetting liquid film on the surface of the photoresist layer; Perform a development treatment on the wafer.
[0006] This application employs two pre-wetting treatments. Through the first pre-wetting treatment, a first pre-wetting liquid film is formed to improve the wettability between the photoresist and the pre-wetting liquid. Subsequently, through the second pre-wetting treatment, a complete second pre-wetting liquid film is formed, thus solving the development defects caused by insufficient pre-wetting. By simply adding one more pre-wetting treatment, this application has good compatibility with existing processes, can make full use of existing equipment and materials, and the entire development process is simple, time-consuming is low, and no additional production costs will be generated. Moreover, through the two pre-wetting treatments, no adverse effects will be exerted on the device, and the overall process yield is high.
[0007] The first pre-wetting treatment includes: rotating the wafer at a first rotation speed and maintaining for a first duration, and spraying the pre-wetting liquid on the surface of the photoresist layer; rotating the wafer at a second rotation speed and maintaining for a second duration to form a film of the pre-wetting liquid on the surface of the photoresist layer; rotating the wafer at a third rotation speed and maintaining for a third duration to remove the excess pre-wetting liquid and form the first pre-wetting liquid film. Through three different rotation speeds, the pre-wetting liquid sprayed on the wafer can be formed into a uniform, complete and appropriately thick pre-wetting liquid film; and through the pre-wetting liquid film formed this time, the surface hydrophobicity can be improved, making it easy to form a defect-free liquid film during the subsequent second pre-wetting treatment.
[0008] The second pre-wetting treatment includes: rotating the wafer at a first rotation speed and maintaining for a first duration, and spraying the pre-wetting liquid on the surface of the first pre-wetting liquid film; rotating the wafer at a second rotation speed and maintaining for a second duration to form a film of the pre-wetting liquid on the surface of the photoresist layer; rotating the wafer at a third rotation speed and maintaining for a fourth duration to remove the excess pre-wetting liquid and form the second pre-wetting liquid film. Through three different rotation speeds, the pre-wetting liquid sprayed on the wafer can be formed into a uniform, complete and appropriately thick pre-wetting liquid film; and by spraying deionized water on the surface of the first pre-wetting liquid film and forming a film, the added deionized water can be better fused with the first pre-wetting liquid film, and then a defect-free second pre-wetting liquid film can be obtained, solving the development defects caused by the incomplete pre-wetting liquid film in the prior art.
[0009] The first rotation speed, the second rotation speed and the third rotation speed increase in sequence; the first rotation speed does not exceed 10 revolutions per minute; the second rotation speed is 400 - 600 revolutions per minute; the third rotation speed is 1000 - 2000 revolutions per minute. Under this process, it is beneficial for the full and uniform spreading of the liquid film, and the liquid film at the edge of the wafer will not be broken due to too high rotation speed, and finally a uniform, complete and appropriately thick liquid film can be obtained.
[0010] The fourth duration is greater than the third duration. In the first pre-wetting process, the time for removing excess liquid can be appropriately reduced, and more pre-wetting liquid can be retained to ensure sufficient wetting during the subsequent second pre-wetting treatment. In the second pre-wetting process, the time for removing excess liquid can be appropriately increased, and an appropriate amount of pre-wetting liquid can be retained to obtain a uniform, complete and appropriately thick liquid film.
[0011] The first duration is at least 0.5 seconds; the second duration is 4 - 6 seconds; the third duration does not exceed 0.5 seconds; the fourth duration is 0.5 - 2 seconds. Reasonably controlling the time for each step is beneficial to the full and uniform spreading of the liquid film and will not cause excessive removal of the liquid due to too long time, making it difficult to form a uniform and complete liquid film.
[0012] In the first pre-wetting treatment, the first rotation speed is 10 revolutions per minute, the first duration is 0.5 seconds, and the spraying rate of the pre-wetting liquid is 900 - 1100 milliliters per minute; the second rotation speed is 500 revolutions per minute, the second duration is 5 seconds; the third rotation speed is 1500 revolutions per minute, the third duration is 0.5 seconds. This process is beneficial to the full and uniform spreading of the liquid film, and a uniform, complete and appropriately thick liquid film can be obtained.
[0013] In the second pre-wetting treatment, the first rotation speed is 10 revolutions per minute, the first duration is 0.5 seconds, and the spraying rate of the pre-wetting liquid is 900 - 1100 milliliters per minute; the second rotation speed is 500 revolutions per minute, the second duration is 5 seconds; the third rotation speed is 1500 revolutions per minute, the third duration is 2 seconds. This process is beneficial to the full and uniform spreading of the liquid film, and a uniform, complete and appropriately thick liquid film can be obtained.
[0014] The development treatment includes: spraying a developer solution onto the surface of the wafer to dissolve the exposed areas in the photoresist layer; cleaning and spin-drying the wafer.
[0015] The pre-wetting liquid is deionized water. Only using deionized water can improve the wetting performance, obtain a complete pre-wetting liquid film, and solve the defects in the prior art. There is no need to adopt overly complicated processes, nor use other chemical solutions, which can reduce costs and reduce possible damage to the device.
[0016] The photoresist layer is a highly hydrophobic photoresist. Good wetting effects can still be achieved when facing a highly hydrophobic photoresist.
[0017] Compared with the prior art, the beneficial effects of the present invention mainly include the following: The present application adopts two pre-wetting treatments. By the first pre-wetting treatment, a first pre-wetting liquid film is formed to improve the wettability of the photoresist and the pre-wetting liquid. Then, by the second pre-wetting treatment, a complete second pre-wetting liquid film is formed, thereby solving the development defects caused by insufficient pre-wetting. The present application only adds one pre-wetting treatment, has good compatibility with the existing process, can make full use of the existing equipment and materials, and the entire development process is simple, time-consuming is low, and no additional production cost will be generated. And through the two pre-wetting treatments, it will not have an adverse impact on the device, and the overall process yield is high. BRIEF DESCRIPTION OF THE DRAWINGS
[0018] In order to more clearly illustrate the technical solutions in the specific embodiments of the present invention, the following will briefly introduce the drawings required for the description of the embodiments. Obviously, the following described drawings are only some embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other drawings can be obtained based on these drawings.
[0019] Figure 1 It is a flowchart of a development process in the prior art.
[0020] Figure 2 It is a flowchart of a development process provided by the present invention. DETAILED DESCRIPTION OF THE EMBODIMENTS
[0021] Regarding the foregoing and other technical contents, features and effects of the present invention, they will be clearly presented in the following detailed description of a preferred embodiment in conjunction with the reference drawings. The directional terms mentioned in the following embodiments, such as: up, down, left, right, front or back, etc., are only with reference to the directions of the attached drawings. Therefore, the directional terms used are for illustration and not for limiting the present invention.
[0022] The following will elaborate on each embodiment of the present application in conjunction with the drawings. However, those of ordinary skill in the art can understand that in each embodiment of the present application, many technical details are proposed for the better understanding of the present application by the readers. However, even without these technical details and various changes and modifications based on the following embodiments, the technical solutions claimed in the present application can still be implemented.
[0023] The steps in the following embodiments do not correspond one by one to the content of the invention.
[0024] As Figure 1 shown is a flowchart of a development process in the prior art.
[0025] Referring to Figure 1 S101 to S104 in, first, a wafer 1 to be developed is provided, and a photoresist layer 2 is formed on the surface of the wafer 1; Referring toFigure 1 In S102, the wafer 1 is pre-wetted with deionized water. Since the hydrophobicity of different photoresist materials is different, when deionized water is spin-pre-wetted on the surface of highly hydrophobic materials, under the action of centrifugal force, liquid molecules will gather more closely together to form droplets, resulting in the discontinuity of the water film 3 (as shown in Figure 1 S102 shown); spray the developer for development processing to dissolve and remove the photoresist in the exposed area. It can be understood that the water film 3 on the surface of the photoresist can help the wetting of the developer 4 and the photoresist. When the formed water film is discontinuous, the developer (DEV) at the water film missing area cannot quickly enter the photoresist, ultimately resulting in incomplete development in this area and forming defects, such as Figure 1 the photoresist residue 21 shown in S104 in
[0026] Example 1 In order to improve the above-mentioned development process defects, the present invention provides a process method for improving development defects, including the following steps: Step 1: Provide a wafer to be developed, and a photoresist layer is formed on the surface of the wafer; Refer to Figure 2 As shown in S201 in
[0027] First, a wafer 1 to be developed is provided, and a photoresist layer 2 is formed on the surface of the wafer 1. It can be understood that the photoresist layer 2 has been exposed, and subsequent development processing is required to pattern the photoresist layer 2. In this embodiment, the photoresist layer 2 is a highly hydrophobic photoresist material, which is more likely to generate the above-mentioned defects. Using this material as an example can better illustrate the technical effects of the present application. In other embodiments, hydrophilic photoresist materials can also be used, which is not limited herein. Refer to Figure 2 As shown in S201 in
[0028] It can be understood that in this embodiment, the pre-wetting liquid is deionized water. In other embodiments, other liquids can also be used, such as a liquid medicine with improved wetting performance. Specifically, in this embodiment, first, the wafer 1 is rotated at a first rotation speed of 10 revolutions per minute (rpm), and deionized water is sprayed onto the surface of the photoresist layer 2. The time of this step (i.e., the first duration) is 0.5 s, and the spraying speed (or flow rate) of the deionized water is 900 - 1100 milliliters per minute. The main purpose of this step is to provide a certain amount of deionized water on the photoresist surface for subsequent film formation. Then, the deionized water on the surface of the wafer 1 is driven to move at a higher rotation speed to evenly spread the deionized water on the surface of the wafer 1, that is, the wafer 1 is rotated at a second rotation speed of 500 rpm and maintained for 5 s (the second duration) to form a film of deionized water on the surface of the photoresist layer 2. Finally, in order to remove the excess deionized water and improve the uniformity of the liquid film, a faster rotation speed can also be used, that is, the wafer 1 is rotated at a third rotation speed of 1500 rpm and maintained for 0.5 s (the third duration) to remove the excess pre-wetting liquid, and finally the first pre-wetting liquid film 31 is obtained. Through three different rotation speeds, a uniform, complete and appropriately thick pre-wetting liquid film can be formed on the pre-wetting liquid sprayed onto the wafer 1.
[0029] It can be understood that this step is similar to the prior art, and the photoresist in this embodiment is a highly hydrophobic material, so the formed first pre-wetting liquid film 31 is also prone to defects, as Figure 2 shown in S201 of
[0030] In other embodiments, the first rotation speed does not exceed 10 rpm; the second rotation speed is 400 - 600 rpm; the third rotation speed is 1000 - 2000 rpm; the first duration is at least 0.5 seconds; the second duration is 4 - 6 seconds; the third duration does not exceed 0.5 seconds.
[0031] Step 3: Perform a second pre-wetting treatment on the wafer to form a second pre-wetting liquid film on the surface of the photoresist layer; Refer to Figure 2 shown in S202 of
[0032] It can be understood that in this embodiment, the pre-wetting liquid is deionized water. In other embodiments, other liquids can also be used, such as a liquid medicine with improved wetting performance. Specifically, in this embodiment, first, the wafer 1 is still rotated at a first rotation speed of 10 revolutions per minute (rpm), and deionized water is added to the surface of the photoresist layer 2. The time for this step (i.e., the first duration) is 0.5 s, and the spraying speed (or flow rate) of the deionized water is 900 - 1100 milliliters per minute. Then, the wafer 1 is rotated at a second rotation speed of 500 rpm and held for 5 s (the second duration) to form a film of deionized water on the surface of the photoresist layer 2. Finally, the wafer 1 is rotated at a third rotation speed of 1500 rpm and held for 2 s (the fourth duration) to remove the excess pre-wetting liquid, and finally the second pre-wetting liquid film 32 is obtained, as shown in Figure 2 S202 shown in
[0033] It can be understood that in this embodiment, a secondary pre-wetting treatment is performed. The first pre-wetting liquid film 31 formed by the first pre-wetting treatment can improve the hydrophobicity of the surface of the wafer 1. Furthermore, when the second pre-wetting treatment is performed, the provided deionized water is in direct contact with the first pre-wetting liquid film 31. With the help of the first pre-wetting liquid film 31, it is easier to reduce the contact angle, so that the uniformity of the finally formed water film is improved, and the second pre-wetting liquid film 32 without defects is obtained.
[0034] In other embodiments, the first rotation speed does not exceed 10 rpm; the second rotation speed is 400 - 600 rpm; the third rotation speed is 1000 - 2000 rpm; the first duration is at least 0.5 seconds; the second duration is 4 - 6 seconds; the third duration does not exceed 0.5 seconds. The fourth duration is greater than the third duration, and the fourth duration is 0.5 - 2 seconds.
[0035] Step 4: Perform a developing treatment on the wafer; Referring to Figure 2 S203 shown in Figure 2 S204 shown in
[0036] Some common English nouns or letters used in this invention for the convenience of clear narration are only for exemplary reference rather than restrictive interpretation or specific usage, and the protection scope of this invention should not be limited by their possible Chinese translations or specific letters.
[0037] It should also be noted that in this text, relational terms such as "first" and "second" are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any actual relationship or order between these entities or operations.
Claims
1. A process method for improving development defects, characterized in that, It includes the following steps: Provide a wafer to be developed, with a photoresist layer formed on the surface of the wafer; Perform a first pre-wetting treatment on the wafer to form a first pre-wetting liquid film on the surface of the photoresist layer; Perform a second pre-wetting treatment on the wafer to form a second pre-wetting liquid film on the surface of the photoresist layer; Perform a developing treatment on the wafer.
2. The process method for improving development defects according to claim 1, characterized in that, The first pre-wetting treatment includes: Rotate the wafer at a first rotation speed and maintain for a first duration, and spray a pre-wetting liquid on the surface of the photoresist layer; Rotate the wafer at a second rotation speed and maintain for a second duration to form a film of the pre-wetting liquid on the surface of the photoresist layer; Rotate the wafer at a third rotation speed and maintain for a third duration to remove the excess pre-wetting liquid and form the first pre-wetting liquid film.
3. A process method for improving development defects according to claim 2, characterized in that, The second pre-wetting treatment includes: Rotate the wafer at a first rotation speed and maintain for a first duration, and spray a pre-wetting liquid on the surface of the first pre-wetting liquid film; Rotate the wafer at a second rotation speed and maintain for a second duration to form a film of the pre-wetting liquid on the surface of the photoresist layer; Rotate the wafer at a third rotation speed and maintain for a fourth duration to remove the excess pre-wetting liquid and form the second pre-wetting liquid film.
4. A process method for improving development defects according to claim 3, characterized in that, The first rotation speed, the second rotation speed, and the third rotation speed increase in sequence; The first rotation speed does not exceed 10 revolutions per minute; The second rotation speed is 400 - 600 revolutions per minute; The third rotation speed is 1000 - 2000 revolutions per minute.
5. A process method for improving development defects according to claim 3, characterized in that, The fourth duration is greater than the third duration.
6. A process method for improving development defects according to claim 5, characterized in that, The first duration is at least 0.5 seconds; the second duration is 4 - 6 seconds; the third duration does not exceed 0.5 seconds; the fourth duration is 0.5 - 2 seconds.
7. A process method for improving development defects according to claim 2, characterized in that, In the first pre-wetting treatment, the first rotation speed is 10 revolutions per minute, the first duration is 0.5 seconds, and the spraying rate of the pre-wetting liquid is 900 - 1100 milliliters per minute; The second rotation speed is 500 revolutions per minute, and the second duration is 5 seconds; The third rotation speed is 1500 revolutions per minute, and the third duration is 0.5 seconds.
8. A process method for improving development defects according to claim 3, characterized in that, In the second pre-wetting treatment, the first rotation speed is 10 revolutions per minute, the first duration is 0.5 seconds, and the spraying rate of the pre-wetting liquid is 900 - 1100 milliliters per minute; The second rotation speed is 500 revolutions per minute, and the second duration is 5 seconds; The third rotation speed is 1500 revolutions per minute, and the third duration is 2 seconds.
9. A process method for improving development defects according to claim 1, characterized in that, The developing treatment includes: Spray a developer on the surface of the wafer to dissolve the exposed area in the photoresist layer; Clean and spin-dry the wafer.
10. A process method for improving development defects according to claim 2 or 3, characterized in that, The pre-wetting liquid is deionized water.
11. A process method for improving development defects according to claim 1, characterized in that, The photoresist layer is a highly hydrophobic photoresist.