Wafer surface photosensitive coating center thickness uniformity spray control device and method

Abstract

The application discloses a wafer surface photosensitive coating center thickness uniform spraying control device and method, relates to the wafer processing technical field, and the technical scheme points are: still include the processor and the reciprocating telescopic mechanism, the output of the processor is connected with the input of the controller, and the output of the controller is connected with the input of the reciprocating telescopic mechanism;The processor is used for generating the drive signal representing the change of the spraying interval with time according to the to-be-processed parameter of the to-be-processed wafer and the actual spraying parameter of the spraying head device;The reciprocating telescopic mechanism is used for adjusting the spraying interval between the spraying head device and the bearing table in response to the drive signal transmitted by the controller, changes the impact force when the photoresist is sprayed to the surface of the to-be-processed wafer, and makes the center thickness of the wafer surface photosensitive coating uniform spraying.The application effectively weakens the influence of the weak centrifugal force of the center of the to-be-processed wafer, can improve the uniformity of the center area 10-20mm of the wafer, and thus improves the wafer quality of the center area.

Description

Technical Field

[0001] This invention relates to the field of wafer processing technology, and more specifically, to a device and method for controlling the uniformity of the center thickness of a photosensitive coating on a wafer surface. Background Technology

[0002] The photolithography process for semiconductor photoconductors typically involves wafer surface cleaning and drying, primer coating, spin-coating of photoresist, soft baking, alignment and exposure, post-baking, development, hard baking, etching, and inspection. However, during spin-coating of photoresist, two issues arise: firstly, the wafer quality is worse in the central region than in the 200mm area; secondly, the weaker centrifugal force in the central region leads to unevenness, causing wafer pattern abnormalities and cd variations. This results in a 10-20mm area diameter unevenness in the optical period uniformity of the semiconductor photoconductor, leading to a lower yield in the central region compared to the 200mm area. Figure 1 As shown.

[0003] In traditional photoresist spraying, the nozzle is primarily aligned with the center of the wafer for spraying, and the stage is rotated to ensure uniform coating of the photoresist under centrifugal force. To overcome the unevenness in the wafer center, some studies have documented methods that control the nozzle to swing left and right in a vertical plane, allowing for a more even distribution of photoresist along the wafer radius. However, because the stage rotates during photoresist spraying, the uniformity of photoresist distribution along the circumference is worse than direct spraying from the center. Therefore, it is necessary to adjust the amount of photoresist per unit time and extend the rotation time of the stage. Furthermore, the radial inertial velocity gained by the photoresist during nozzle swinging can easily cause it to overflow from the wafer edge, thus affecting the quality of the photoresist coating.

[0004] Therefore, how to research and design a device and method for controlling the uniform center thickness of photosensitive coatings on wafer surfaces that can overcome the above-mentioned defects is an urgent problem that we need to solve. Summary of the Invention

[0005] To address the shortcomings of existing technologies, the present invention aims to provide a device and method for controlling the uniformity of the center thickness of photosensitive coatings on wafer surfaces, which can improve the uniformity of the wafer center area by 10-20 mm, thereby improving the wafer quality in the center area.

[0006] The above-mentioned technical objective of the present invention is achieved through the following technical solution:

[0007] In the first aspect, a uniform center thickness spraying control device for photosensitive coating on wafer surface is provided, including a carrier stage, a spray head device and a controller. The controller is used to control the rotation of the carrier stage and control the spray head device to spray photoresist onto the wafer to be processed on the carrier stage. It also includes a processor and a reciprocating telescopic mechanism. The output end of the processor is connected to the input end of the controller, and the output end of the controller is connected to the input end of the reciprocating telescopic mechanism.

[0008] The processor is used to generate a drive signal characterizing the change of the spraying distance over time based on the processing parameters of the wafer to be processed and the actual spraying parameters of the nozzle device.

[0009] The reciprocating telescopic mechanism is used to adjust the spraying distance between the nozzle device and the support platform in response to the drive signal transmitted by the controller. By changing the impact force when the photoresist is sprayed onto the surface of the wafer to be processed, the center thickness of the photosensitive coating on the wafer surface is uniformly sprayed.

[0010] Furthermore, the reciprocating telescopic mechanism is a single unit, which is installed vertically on the support platform or nozzle device.

[0011] Furthermore, two reciprocating telescopic mechanisms are used, and the two reciprocating telescopic mechanisms are respectively installed on the support platform and the nozzle device in the vertical direction.

[0012] Furthermore, the two reciprocating telescopic mechanisms respond to the drive signal by driving synchronously in opposite directions or in opposite directions.

[0013] Furthermore, the driving signal consists of a first signal and a second signal. One reciprocating telescopic mechanism responds to the first signal to complete the driving, and the other reciprocating telescopic mechanism responds to the second signal to complete the driving.

[0014] In a second aspect, a method for controlling the uniform center thickness of a photosensitive coating on a wafer surface is provided. This method is used in the uniform center thickness spraying control device for a photosensitive coating on a wafer surface as described in any one of the first aspects, and includes the following steps:

[0015] The processor generates a drive signal that characterizes the change of spraying distance over time based on the processing parameters of the wafer to be processed and the actual spraying parameters of the nozzle device.

[0016] The reciprocating telescopic mechanism adjusts the spraying distance between the nozzle device and the carrier platform after responding to the drive signal transmitted by the controller. By changing the impact force when the photoresist is sprayed onto the surface of the wafer to be processed, the center thickness of the photosensitive coating on the wafer surface is uniformly sprayed.

[0017] Furthermore, the processing parameters include coating thickness, coating range, and coating uniformity.

[0018] Furthermore, the actual spraying parameters include photoresist viscosity, photoresist concentration, spraying speed, and spraying flow rate.

[0019] Furthermore, the frequency information of the driving signal is inversely correlated with both the photoresist viscosity and photoresist concentration, and positively correlated with both the spraying speed and spraying flow rate.

[0020] Furthermore, the amplitude information of the driving signal is positively correlated with the photoresist viscosity, photoresist concentration, and spraying flow rate, and negatively correlated with the spraying speed.

[0021] Compared with the prior art, the present invention has the following beneficial effects:

[0022] 1. The wafer surface photosensitive coating uniformity spraying control device proposed in this invention adjusts the spraying distance between the spraying device and the support platform in the vertical direction by repeatedly adjusting the spraying distance over time. This changes the straight-line distance between the spraying device and the wafer surface to be processed, so that the impact force of the photoresist on the wafer surface after the initial spraying velocity and the acceleration due to gravity changes dynamically. This allows the photoresist to diffuse outward in a range, ensuring that the two sides of the photoresist spraying can be more evenly distributed. This effectively weakens the influence of the weak centrifugal force at the center of the wafer to be processed and improves the thickness uniformity between the central and peripheral areas of the wafer.

[0023] 2. The present invention uses two reciprocating telescopic mechanisms to drive synchronously in opposite directions or in opposite directions in response to the drive signal, which can effectively improve the efficiency of spraying spacing control and adapt to the rapid rotation of the support platform.

[0024] 3. The present invention takes into account multiple factors such as photoresist viscosity, photoresist concentration, spraying speed and spraying flow rate when generating the driving signal, so that the frequency information and amplitude information in the driving signal are more accurate, and further enhances the thickness uniformity between the central region and the peripheral region of the wafer. Attached Figure Description

[0025] 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:

[0026] Figure 1 This is a schematic diagram of the structure of a photoresist spraying device in the prior art;

[0027] Figure 2 This is a schematic diagram of the overall structure in an embodiment of the present invention.

[0028] The attached diagram shows the markings and corresponding component names:

[0029] 1. Nozzle assembly; 2. Support platform; 3. Reciprocating telescopic mechanism. Detailed Implementation

[0030] 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.

[0031] It should be noted that when a component is referred to as being "fixed to" or "set on" another component, it can be directly or indirectly attached to that other component. When a component is referred to as being "connected to" another component, it can be directly or indirectly connected to that other component.

[0032] It should be understood that the terms "length", "width", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on the present invention.

[0033] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of this invention, "a plurality of" means two or more, unless otherwise explicitly specified.

[0034] Example: A device for controlling the uniform thickness of the center layer of a photosensitive coating on a wafer surface, such as... Figure 2 As shown, the system includes a support platform 2, a nozzle assembly 1, a controller, a processor, and a reciprocating telescopic mechanism 3. The controller controls the rotation of the support platform 2 and the spraying of photoresist from the nozzle assembly 1 onto the wafer to be processed on the support platform 2. The output of the processor is connected to the input of the controller, and the output of the controller is connected to the input of the reciprocating telescopic mechanism 3. The processor generates a drive signal characterizing the change of the spraying distance over time based on the processing parameters of the wafer to be processed and the actual spraying parameters of the nozzle assembly 1. The reciprocating telescopic mechanism 3 adjusts the spraying distance between the nozzle assembly 1 and the support platform 2 in response to the drive signal transmitted by the controller, thereby changing the impact force when the photoresist is sprayed onto the surface of the wafer to ensure uniform spraying of the center thickness of the photosensitive coating on the wafer surface.

[0035] As an optional implementation, one reciprocating telescopic mechanism 3 may be used, which is installed vertically on the support platform 2 or the nozzle device 1.

[0036] As an alternative implementation, two reciprocating telescopic mechanisms 3 are used, with the two mechanisms 3 mounted vertically on the support platform 2 and the nozzle device 1 respectively. The two reciprocating telescopic mechanisms 3 can respond to a drive signal and drive synchronously in opposite directions or in opposite directions. Furthermore, the drive signal can also consist of a first signal and a second signal. One reciprocating telescopic mechanism 3 responds to the first signal to complete the drive, and the other responds to the second signal to complete the drive. The first and second signals can drive synchronously or sequentially, effectively improving the efficiency of spray spacing control and adapting to the rapid rotation of the support platform 2.

[0037] In this embodiment, the reciprocating telescopic mechanism 3 can be an electric telescopic rod, a linear drive cylinder, or other precision structures with reciprocating linear drive, and is not limited thereto.

[0038] The processing parameters include, but are not limited to, coating thickness, coating range, and coating uniformity. Actual coating parameters include photoresist viscosity, photoresist concentration, coating speed, and coating flow rate. It should be noted that the coating spacing can be controlled by acquiring parameter information in real time through different sensors and performing real-time analysis using fluid dynamics. Alternatively, a distance-related function can be obtained based on pre-simulation analysis, and the spacing can be dynamically adjusted after real-time scanning.

[0039] In this embodiment, the frequency information of the driving signal is inversely correlated with both the photoresist viscosity and photoresist concentration, and positively correlated with both the spraying speed and spraying flow rate. Conversely, the amplitude information of the driving signal is positively correlated with both the photoresist viscosity, photoresist concentration, and spraying flow rate, and inversely correlated with the spraying speed.

[0040] Working principle: This invention adjusts the vertical spraying distance between the spraying device and the support platform 2 repeatedly over time, thereby changing the straight-line distance between the spraying device and the surface of the wafer to be processed. This causes the impact force of the photoresist on the wafer surface after the initial spraying velocity and the acceleration due to gravity to change dynamically, so that the photoresist diffuses outward in a range, ensuring that the two sides of the photoresist spraying can be more evenly distributed. This effectively weakens the influence of the weak centrifugal force at the center of the wafer to be processed, and improves the thickness uniformity between the central and peripheral areas of the wafer.

[0041] 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 wafer surface photosensitive coating uniform center thickness spraying control device, comprising a carrier stage (2), a spray head device (1), and a controller, wherein the controller is used to control the rotation of the carrier stage (2) and to control the spray head device (1) to spray photoresist onto the wafer to be processed on the carrier stage (2), characterized in that, It also includes a processor and a reciprocating telescopic mechanism (3), the output of the processor is connected to the input of the controller, and the output of the controller is connected to the input of the reciprocating telescopic mechanism (3); The processor is used to generate a driving signal characterizing the change of the spraying distance over time based on the processing parameters of the wafer to be processed and the actual spraying parameters of the nozzle device (1); the processing parameters include spraying thickness, spraying range and spraying uniformity; the actual spraying parameters include photoresist viscosity, photoresist concentration, spraying speed and spraying flow rate; The reciprocating telescopic mechanism (3) is used to adjust the spraying distance between the nozzle device (1) and the support platform (2) in response to the drive signal transmitted by the controller. By changing the impact force when the photoresist is sprayed onto the surface of the wafer to be processed, the center thickness of the photosensitive coating on the wafer surface is uniformly sprayed.

2. The wafer surface photosensitive coating center thickness uniform spraying control device according to claim 1, characterized in that, One reciprocating telescopic mechanism (3) is used, and the reciprocating telescopic mechanism (3) is installed vertically on the support platform (2) or the nozzle device (1).

3. The wafer surface photosensitive coating center thickness uniform spraying control device according to claim 1, characterized in that, Two reciprocating telescopic mechanisms (3) are used, and the two reciprocating telescopic mechanisms (3) are respectively installed on the support platform (2) and the nozzle device (1) in the vertical direction.

4. The wafer surface photosensitive coating center thickness uniform spraying control device according to claim 3, characterized in that, The two reciprocating telescopic mechanisms (3) respond to the drive signal and drive synchronously in opposite directions or in opposite directions.

5. The wafer surface photosensitive coating center thickness uniform spraying control device according to claim 3, characterized in that, The driving signal consists of a first signal and a second signal. One reciprocating telescopic mechanism (3) responds to the first signal to complete the driving, and the other reciprocating telescopic mechanism (3) responds to the second signal to complete the driving.

6. A method for controlling the uniform thickness of the center layer of a photosensitive coating on a wafer surface, characterized in that: This control method is used in the wafer surface photosensitive coating center thickness uniform spraying control device as described in any one of claims 1-5, and includes the following steps: The processor generates a driving signal characterizing the change of the spraying distance over time based on the processing parameters of the wafer to be processed and the actual spraying parameters of the nozzle device (1); the processing parameters include spraying thickness, spraying range and spraying uniformity; the actual spraying parameters include photoresist viscosity, photoresist concentration, spraying speed and spraying flow rate; The reciprocating telescopic mechanism (3) adjusts the spraying distance between the nozzle device (1) and the carrier platform (2) in response to the drive signal transmitted by the controller. By changing the impact force when the photoresist is sprayed onto the surface of the wafer to be processed, the center thickness of the photosensitive coating on the wafer surface is uniformly sprayed.

7. The method for controlling the uniform center thickness of the photosensitive coating on the wafer surface according to claim 6, characterized in that, The frequency information of the driving signal is inversely correlated with both the viscosity and concentration of the photoresist, and positively correlated with both the spraying speed and the spraying flow rate.

8. The method for controlling the uniform center thickness of the photosensitive coating on the wafer surface according to claim 6, characterized in that, The amplitude of the driving signal is positively correlated with the photoresist viscosity, photoresist concentration, and spraying flow rate, and negatively correlated with the spraying speed.

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