A photoresist coating system and method for wafers
By circulating and filtering the photoresist in the photoresist coating system, the amount of photoresist in the pressure pump is kept constant, which solves the problem of inconsistent photoresist spraying pressure, achieves uniform photoresist thickness on the wafer, and improves the quality of semiconductor products.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- CHENGDU HIGH-TECH JIN SCI&TECH CO LTD
- Filing Date
- 2021-10-11
- Publication Date
- 2026-07-10
AI Technical Summary
In semiconductor manufacturing, existing photoresist spraying systems suffer from inconsistent spraying pressures due to varying amounts of residual photoresist in the pump, resulting in uneven photoresist thickness and impacting product quality.
Design a photoresist coating system that uses a pressure pump and a photoresist filter for cyclic filtration to ensure that a fixed amount of photoresist is stored in the pressure pump each time it is sprayed, thus achieving constant pressure spraying.
This achieves consistent photoresist coating thickness across different wafers, avoiding product defects in semiconductor manufacturing.
Smart Images
Figure CN115963698B_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the field of semiconductor manufacturing technology, and more specifically to a photoresist coating system and method for wafers. Background Technology
[0002] As semiconductor process patterns become increasingly smaller, the level of particle refinement management also improves. Related photoresist management is no longer limited to hard defect management and gel defects; the impact of defects caused by stagnation (residue) is also gaining attention. The existing photoresist spraying process for wafers is described in [link to existing technology]. Figure 2 In semiconductor manufacturing, when applying photoresist to wafers, the IMMERSION standard process typically uses a 3cc (3 ml) pump. The actual amount of photoresist used to coat one wafer is between 1cc (1 ml) and 0.6cc (0.6 ml). Assuming the actual amount of photoresist used per wafer is 1cc, then during the first coat (coating the first wafer), 1cc of photoresist is used, leaving 2cc. During the second coat (coating the second wafer), another 1cc is used, leaving 1cc. During the third coat (coating the third wafer), another 1cc is used, and so on, until the photoresist in the pump is depleted. Only then is photoresist injected through a filter for subsequent coats.
[0003] The problem is this: In semiconductor manufacturing, during photoresist coating of wafers, the IMMERSION standard process typically uses a 3cc pump. Generally, 1cc of photoresist can coat three wafers. However, there are three scenarios: 1) 1cc of photoresist is sprayed onto the wafer when the pump contains 3cc; 2) 1cc is sprayed onto the wafer when the pump contains 2cc; and 1cc is sprayed onto the wafer when the pump contains 1cc. In these three scenarios, the remaining photoresist volume in the pump varies, resulting in inconsistent pressure transmitted through the pump. This leads to increasingly larger errors with each coating cycle. Specifically, the inconsistent pressure refers to the different amounts of photoresist sprayed onto the wafer in each cycle. This inconsistent amount of photoresist sprayed onto the wafer results in inconsistent photoresist thickness during coating, which in turn contributes to product defects in semiconductor manufacturing. Summary of the Invention
[0004] The purpose of this invention is to provide a photoresist coating system and method for wafers, addressing the problems existing in the prior art. In this system, a fixed amount of photoresist is stored in the pressure pump during each coating cycle, ensuring consistent pump pressure and thus consistent flow rate and coating thickness on the wafer. This achieves constant pressure photoresist coating on different wafers, thereby avoiding product defects in semiconductor manufacturing.
[0005] This invention is achieved through the following technical solution:
[0006] In a first aspect, the present invention provides a photoresist coating system for wafers, the system comprising a pressure pump unit, the pressure pump unit including a photoresist filter and a pressure pump; the inlet of the photoresist filter is connected to a photoresist supply unit, and the outlet of the photoresist filter is connected to the inlet of the pressure pump, thereby filtering the photoresist input from the photoresist supply unit; the first outlet of the pressure pump is connected to a spraying rotation unit, and a constant spraying amount of photoresist is output from the first outlet to perform a single photoresist spraying operation on the wafer of the subsequent spraying rotation unit;
[0007] The second outlet of the pressure pump is connected to the inlet of the photoresist filter. After one spraying, the remaining photoresist is circulated out through the second outlet to the photoresist filter for processing. A fixed amount of photoresist is then sent to the pressure pump for the next photoresist spraying, so that a fixed amount of photoresist is stored in the pressure pump during each spraying, thereby achieving constant pressure photoresist spraying on different wafers of the spraying rotating unit.
[0008] This invention improves upon existing photoresist spraying systems for wafers. After the initial photoresist spraying, the remaining photoresist in the pressure pump is not used for a second spray. Instead, it is reloaded into the inlet of the photoresist filter for filtration, and then a fixed amount of photoresist is sent to the pressure pump for the next spray. This ensures a consistent amount of photoresist in the pressure pump during each spray, guaranteeing a uniform pressure and thus a consistent flow rate and coating thickness on the wafer. This achieves constant pressure photoresist spraying on different wafers, thereby avoiding defects in semiconductor manufacturing.
[0009] Furthermore, it also includes a photoresist supply unit, which comprises a first photoresist bottle, a second photoresist bottle, a first empty photoresist buffer tank, a second empty photoresist buffer tank, a bottle exchange control unit, and a bubble removal buffer tank. The bubble removal buffer tank is used to remove bubbles during the photoresist supply process. The first photoresist bottle is connected to the first empty photoresist buffer tank, and the second photoresist bottle is connected to the second empty photoresist buffer tank. Both the first and second empty photoresist buffer tanks are connected to the bubble removal buffer tank via the bottle exchange control unit. The bubble removal buffer tank is connected to the pressure pump unit.
[0010] In the photoresist supply unit, the first photoresist bottle serves as the main supply photoresist bottle, and the second photoresist bottle serves as the backup supply photoresist bottle. When the main supply photoresist bottle is temporarily exhausted and has not been replaced in time, the supply can be switched to the backup supply photoresist bottle through the bottle exchange control unit to ensure uninterrupted supply of photoresist.
[0011] Furthermore, the first photoresist empty buffer tank, the second photoresist empty buffer tank, and the bubble removal buffer tank are all equipped with exhaust pipes for venting during the photoresist supply process.
[0012] Furthermore, each time a coating is applied, the pressure pump contains a fixed amount of photoresist, which is 3 ml, 5 ml, or 8 ml.
[0013] Furthermore, a constant amount of photoresist is output through the first outlet to perform a photoresist spraying on the wafer of the subsequent spraying rotation unit, wherein the constant spraying amount is any fixed value between 0.6 ml and 1 ml.
[0014] Furthermore, the photoresist filter is provided with an exhaust pipe for venting during the photoresist filtration process.
[0015] Secondly, the present invention also provides a method for applying photoresist to a wafer, the method being applied to the aforementioned photoresist coating system for a wafer; the method comprising:
[0016] Obtain the photoresist liquid and filter it through a photoresist filter;
[0017] A fixed amount of filtered photoresist liquid is fed into a pressure pump, and a constant amount of photoresist is output from the first outlet of the pressure pump to achieve one photoresist spraying on the wafer.
[0018] After one spraying is completed, the remaining photoresist in the pressure pump is circulated to the photoresist filter through the second outlet of the pressure pump; after a second filtration, a fixed amount of photoresist is sent to the pressure pump for the next photoresist spraying.
[0019] Each time a photoresist is applied, the pressure pump stores a fixed amount of photoresist, thereby achieving constant pressure photoresist application on different wafers in the future.
[0020] Compared with the prior art, the present invention has the following advantages and beneficial effects:
[0021] This invention improves upon existing photoresist spraying systems for wafers. After the initial photoresist spraying, the remaining photoresist in the pressure pump is not used for a second spray. Instead, it is reloaded into the inlet of the photoresist filter for filtration, and then a fixed amount of photoresist is sent to the pressure pump for the next spray. This ensures a consistent amount of photoresist in the pressure pump during each spray, guaranteeing a uniform pressure and thus a consistent flow rate and coating thickness on the wafer. This achieves constant pressure photoresist spraying on different wafers, thereby avoiding defects in semiconductor manufacturing. Attached Figure Description
[0022] The accompanying drawings, which are included to provide a further understanding of embodiments of the invention and form part of this application, do not constitute a limitation thereof. In the drawings:
[0023] Figure 1 This is a block diagram of a photoresist coating system for wafers according to an embodiment of the present invention.
[0024] Figure 2 This is a schematic diagram illustrating the pump operation sequence in a conventional photoresist coating system for wafers.
[0025] Figure 3 This is a schematic diagram illustrating the operating sequence of the pressure pump in a photoresist coating system for wafers according to the present invention.
[0026] Figure reference numerals and corresponding component names:
[0027] 1-Photoresist filter, 2-Pressure pump, 3-Wafer, 4-First photoresist bottle, 5-Second photoresist bottle, 6-First empty photoresist buffer tank, 7-Second empty photoresist buffer tank, 8-Bottle exchange control unit, 9-Bubble removal buffer tank, 10-Exhaust pipe, 11-Outlet, 12-Switch valve. Detailed Implementation
[0028] In the following, the terms “comprising” or “may include” as used in various embodiments of the invention indicate the presence of an inventive function, operation, or element, and do not limit the addition of one or more functions, operations, or elements. Furthermore, as used in various embodiments of the invention, the terms “comprising,” “having,” and their cognates are intended only to indicate a specific feature, number, step, operation, element, component, or combination of the foregoing, and should not be construed as primarily excluding the presence of one or more other features, numbers, steps, operations, elements, components, or combinations of the foregoing, or adding one or more combinations of the foregoing.
[0029] In various embodiments of the invention, the expression "or" or "at least one of A and / or B" includes any combination or all combinations of the words listed simultaneously. For example, the expression "A or B" or "at least one of A and / or B" may include A, may include B, or may include both A and B.
[0030] The expressions used in the various embodiments of the present invention (such as "first," "second," etc.) may modify various constituent elements in the various embodiments, but do not limit the corresponding constituent elements. For example, the above expressions do not limit the order and / or importance of the elements. The above expressions are only used for the purpose of distinguishing one element from other elements. For example, a first user device and a second user device refer to different user devices, although both are user devices. For example, a first element may be referred to as a second element without departing from the scope of the various embodiments of the present invention, and similarly, a second element may also be referred to as a first element.
[0031] It should be noted that if a description is made of "connecting" one component to another, then the first component can be directly connected to the second component, and a third component can be "connected" between the first and second components. Conversely, when a component is "directly connected" to another component, it can be understood that there is no third component between the first and second components.
[0032] The terminology used in the various embodiments of the invention is for the purpose of describing particular embodiments only and is not intended to limit the various embodiments of the invention. As used herein, the singular form is intended to include the plural form as well, unless the context clearly indicates otherwise. Unless otherwise defined, all terms used herein (including technical and scientific terms) have the same meaning as commonly understood by one of ordinary skill in the art to which the various embodiments of the invention pertain. The terms (such as those defined in a generally used dictionary) are to be interpreted as having the same meaning as in the context of the relevant technical field and are not to be interpreted as having an idealized or overly formal meaning, unless clearly defined in the various embodiments of the invention.
[0033] To make the objectives, technical solutions, and advantages of the present invention clearer, the present invention will be further described in detail below with reference to the embodiments and accompanying drawings. The illustrative embodiments and descriptions of the present invention are only used to explain the present invention and are not intended to limit the present invention.
[0034] Example 1
[0035] like Figures 1 to 3 As shown, the present invention provides a photoresist coating system for wafers, such as... Figure 1 As shown, the system includes a pressure pump unit, which includes a photoresist filter 1 and a pressure pump 2. The inlet of the photoresist filter 1 is connected to the photoresist supply unit, and the outlet of the photoresist filter 1 is connected to the inlet of the pressure pump 2. The photoresist input from the photoresist supply unit is filtered through the photoresist filter 1. The first outlet of the pressure pump 2 is connected to the spraying rotation unit. A constant amount of photoresist is output through the first outlet to perform one photoresist spraying on the wafer 3 of the subsequent spraying rotation unit.
[0036] The second outlet of the pressure pump 2 is connected to the inlet of the photoresist filter 1. After one spraying, the remaining photoresist is circulated out through the second outlet to the photoresist filter 1 for processing. A fixed amount of photoresist is then sent to the pressure pump 2 for the next photoresist spraying, so that a fixed amount of photoresist is stored in the pressure pump 2 each time it is sprayed, thereby achieving constant pressure photoresist spraying on different wafers 3 of the spraying rotating unit.
[0037] In specific implementation, the first outlet and the second outlet of the pressure pump 2 can be the same outlet. This outlet 11 is connected to the spraying rotary unit, and at the same time, it can be connected to the inlet of the photoresist filter 1 through a switching valve 12.
[0038] To further illustrate this embodiment, the system of the present invention also includes a photoresist supply unit, which includes a first photoresist bottle 4, a second photoresist bottle 5, a first empty photoresist buffer tank 6, a second empty photoresist buffer tank 7, a bottle exchange control unit 8, and a bubble removal buffer tank 9. The bubble removal buffer tank 9 is used to remove bubbles during the photoresist supply process. The first photoresist bottle 4 is connected to the first empty photoresist buffer tank 6, and the second photoresist bottle 5 is connected to the second empty photoresist buffer tank 7. Both the first empty photoresist buffer tank 6 and the second empty photoresist buffer tank 7 are connected to the bubble removal buffer tank 9 through the bottle exchange control unit 8. The bubble removal buffer tank 9 is connected to the pressure pump unit.
[0039] In the photoresist supply unit, the first photoresist bottle 4 serves as the main photoresist supply bottle, and the second photoresist bottle 5 serves as the backup photoresist supply bottle. When the main photoresist supply bottle is temporarily exhausted and there is no time to replace it, the bottle exchange control unit 8 can be used to switch to the backup photoresist supply bottle to ensure uninterrupted photoresist supply.
[0040] To further illustrate this embodiment, the first photoresist empty buffer tank 6, the second photoresist empty buffer tank 7, and the bubble removal buffer tank 9 are all equipped with exhaust pipes 10 for venting during the photoresist supply process.
[0041] To further illustrate this embodiment, each time the pressure pump 2 contains a fixed amount of photoresist, wherein the fixed amount is 3 ml, 5 ml, or 8 ml.
[0042] To further illustrate this embodiment, a photoresist coating is performed on the wafer 3 of the subsequent coating rotation unit by outputting a constant amount of photoresist through the first outlet, wherein the constant coating amount is any fixed value between 0.6 ml and 1 ml.
[0043] To further illustrate this embodiment, the photoresist filter 1 is provided with an exhaust pipe 10 for exhausting air during the photoresist filtration process.
[0044] The working principle is as follows:
[0045] The existing process for photoresist spraying on wafers is described below. Figure 2 In semiconductor manufacturing, during photoresist coating of wafers, the IMMERSION standard process typically uses a 3cc (3 ml) pump. The actual amount of photoresist used to coat one wafer is between 1cc (1 ml) and 0.6cc (0.6 ml). Assuming the actual amount of photoresist used per wafer is 1cc, then during the first coating (coating the first wafer), 1cc of photoresist is used, leaving 2cc. During the second coating (coating the second wafer), another 1cc is used, leaving 1cc. During the third coating (coating the third wafer), another 1cc is used, and so on, until the photoresist in the pump is depleted. Only then is additional photoresist injected through a filter for subsequent coatings. Specifically… Figure 2 The sequence of operation for the pump is "Wait (preparation) → Dispense (spraying) → Reload (Refill)"; where Nozzle refers to the nozzle.
[0046] The problem is this: In semiconductor manufacturing, during photoresist coating of wafers, the IMMERSION standard process typically uses a 3cc pump. Generally, 1cc of photoresist can be sprayed onto three wafers. However, there are three scenarios: 1) 1cc of photoresist is sprayed onto the wafer when the pump contains 3cc; 2) 1cc is sprayed onto the wafer when the pump contains 2cc; and 1) 1cc is sprayed onto the wafer when the pump contains 1cc. In these three scenarios, the remaining photoresist volume in the pump varies, resulting in inconsistent pressure transmitted through the pump. This leads to increasingly larger errors with each coating. Specifically, the inconsistent pressure refers to the different amounts of photoresist sprayed onto the wafer in each coating cycle. This inconsistent amount of photoresist sprayed onto the wafer results in inconsistent photoresist thickness during coating, ultimately leading to product defects in semiconductor manufacturing.
[0047] Therefore, this invention designs a photoresist coating system for wafers, solving the problem of inconsistent photoresist liquid volume sprayed onto the wafer due to varying spray pressures of the pressure pump each time, resulting in inconsistent photoresist thickness during coating and thus product defects in semiconductor manufacturing. This invention improves upon existing photoresist spraying systems for wafers. After the first spray of photoresist, the remaining photoresist in the pressure pump is not used for a second spray. Instead, the remaining photoresist is reloaded into the inlet of the photoresist filter 1 for filtration again, and then a fixed amount of photoresist is sent to the pressure pump for the next spray. This ensures that a fixed amount of photoresist is stored in the pressure pump for each spray, guaranteeing consistent pressure transmission and thus consistent flow rate onto the wafer 3, resulting in consistent photoresist thickness during coating. This achieves constant pressure photoresist spraying on different wafers 3, thereby avoiding product defects in semiconductor manufacturing.
[0048] The working process is as follows: According to the IMMERSION standard process, this embodiment uses a 3cc capacity pressure pump 2, and the constant spraying amount for one wafer 3 is 1cc. After the photoresist is sprayed once (using 1cc of photoresist liquid), the remaining photoresist in the pressure pump 2 (the remaining amount of photoresist is 2cc) is not used for a second spray. Instead, the remaining photoresist in the pressure pump 2 is reloaded to the inlet of the photoresist filter 1, filtered again, and then a fixed amount (3cc) of photoresist is sent to the pressure pump 2 for the next photoresist spraying. This ensures that the pressure pump 2 stores a fixed amount (3cc) of photoresist each time it is sprayed, guaranteeing that the pressure transmitted on the pressure pump 2 is the same, and thus the flow rate sprayed onto the wafer 3 is also the same; thereby achieving constant pressure photoresist spraying on different wafers 3. For the specific working sequence of the pressure pump 2, see [link to relevant documentation]. Figure 3 .
[0049] Figure 3 The operating sequence of a medium-pressure pump is "Wait (preparation) → Dispense (spraying) → Recycle (Refill) → Reload"; where Recycle refers to recycling, Nozzle refers to the nozzle, and Filter refers to the filter.
[0050] Example 2
[0051] like Figure 1 , Figure 3 As shown, the difference between this embodiment and Embodiment 1 is that this embodiment provides a photoresist coating method for wafers, which is applied to the photoresist coating system for wafers described in Embodiment 1; the method includes:
[0052] Obtain the photoresist liquid and filter it through a photoresist filter;
[0053] A fixed amount of filtered photoresist liquid is fed into a pressure pump, and a constant amount of photoresist is output from the first outlet of the pressure pump to achieve one photoresist spraying on the wafer.
[0054] After one spraying is completed, the remaining photoresist in the pressure pump is circulated to the photoresist filter through the second outlet of the pressure pump; after a second filtration, a fixed amount of photoresist is sent to the pressure pump for the next photoresist spraying.
[0055] Each time a photoresist is applied, the pressure pump stores a fixed amount of photoresist, thereby achieving constant pressure photoresist application on different wafers in the future.
[0056] In this invention, the coating method involves a process where, after the initial photoresist spraying, the remaining photoresist in the pressure pump is not used for a second spray. Instead, the remaining photoresist is reloaded into the inlet of the photoresist filter for filtration. A fixed amount of photoresist is then sent to the pressure pump for the next photoresist spraying cycle. This ensures that a fixed amount of photoresist is stored in the pressure pump for each spraying cycle, guaranteeing consistent pressure and thus consistent flow rate onto the wafer, resulting in uniform photoresist thickness during coating. This achieves constant pressure photoresist spraying on different wafers, thereby avoiding product defects in semiconductor manufacturing.
[0057] The specific embodiments described above further illustrate the purpose, technical solution, and beneficial effects of the present invention. It should be understood that the above description is only a specific embodiment of the present invention and is not intended to limit the scope of protection of the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.
Claims
1. A photoresist coating system for wafers, the system comprising a pressure pump unit and a photoresist supply unit, the pressure pump unit comprising a photoresist filter and a pressure pump; the inlet of the photoresist filter is connected to the photoresist supply unit, and the outlet of the photoresist filter is connected to the inlet of the pressure pump, wherein the photoresist input to the photoresist supply unit is filtered through the photoresist filter; characterized in that, The first outlet of the pressure pump is connected to the spraying rotation unit, and a constant amount of photoresist is output through the first outlet to perform a photoresist spraying on the wafer of the subsequent spraying rotation unit. The second outlet of the pressure pump is connected to the inlet of the photoresist filter. After one spraying, the remaining photoresist is circulated out through the second outlet to the photoresist filter for processing. A fixed amount of photoresist is then sent to the pressure pump for the next photoresist spraying, so that a fixed amount of photoresist is stored in the pressure pump during each spraying, thereby achieving constant pressure photoresist spraying on different wafers of the spraying rotating unit. The photoresist supply unit includes a first photoresist bottle, a second photoresist bottle, a first empty photoresist buffer tank, a second empty photoresist buffer tank, a bottle exchange control unit, and a bubble removal buffer tank. The first photoresist bottle is connected to the first empty photoresist buffer tank, and the second photoresist bottle is connected to the second empty photoresist buffer tank. Both the first empty photoresist buffer tank and the second empty photoresist buffer tank are connected to the bubble removal buffer tank through the bottle exchange control unit. The bubble removal buffer tank is connected to the pressure pump unit.
2. The photoresist coating system for wafers according to claim 1, characterized in that, The first photoresist empty buffer tank, the second photoresist empty buffer tank, and the bubble removal buffer tank are all equipped with exhaust pipes.
3. The photoresist coating system for wafers according to claim 1, characterized in that, Each time a photoresist is applied, the pressure pump contains a fixed amount of photoresist, which is either 3 ml, 5 ml, or 8 ml.
4. The photoresist coating system for wafers according to claim 1, characterized in that, A constant amount of photoresist is output from the first outlet to perform a single photoresist spraying on the wafer of the subsequent spraying rotation unit, wherein the constant spraying amount is any fixed value between 0.6 ml and 1 ml.
5. A method for applying photoresist to wafers, characterized in that, This method is applied to a photoresist coating system for wafers as described in any one of claims 1 to 4; the method includes: Obtain the photoresist liquid and filter it through a photoresist filter; A fixed amount of filtered photoresist liquid is fed into a pressure pump, and a constant amount of photoresist is output from the first outlet of the pressure pump to achieve one photoresist spraying on the wafer. After one spraying is completed, the remaining photoresist in the pressure pump is circulated to the photoresist filter through the second outlet of the pressure pump; after a second filtration, a fixed amount of photoresist is sent to the pressure pump for the next photoresist spraying. Each time a photoresist is applied, the pressure pump stores a fixed amount of photoresist, thereby achieving constant pressure photoresist application on different wafers in the future.