Device for preventing secondary pollution of wafer coating

Abstract

The invention discloses a device for preventing secondary pollution of a wafer coating, and relates to the technical field of semiconductor manufacturing, the device comprises a bottom frame and a rotating chuck used for rotating and bearing a wafer, and further comprises a lifting frame vertically connected to the bottom frame in a sliding mode and an anti-splashing assembly arranged on the lifting frame, the collecting bowl is fixedly connected to the lifting frame, and an inner cavity of the collecting bowl surrounds the rotating chuck and is used for collecting the scattered coating liquid; the anti-springback structure comprises a main body sleeve fixedly connected to the collecting bowl; according to the device for preventing the secondary pollution of the wafer coating, the wafer is driven to rotate at a high speed, and meanwhile, the nozzle is supplied to drip the coating liquid. After splashing coating liquid impacts the inner wall of the conical guide cavity, most of kinetic energy is absorbed and flows downwards along the wall face. A small number of rebound liquid drops with large vertical upward components are directly impacted and blocked by the bottom face of the annular edge when moving upwards. And the blocked liquid drops are attached to the bottom surface of the edge, are accumulated into drops and then drop downwards.

Description

Technical Field

[0001] This invention relates to the field of semiconductor manufacturing technology, specifically to a device for preventing secondary contamination of wafer coatings. Background Technology

[0002] In the photolithography process of semiconductor manufacturing, it is necessary to uniformly coat the wafer surface with a coating liquid such as photoresist. Currently, spin coating technology is commonly used, which uses the centrifugal force of high-speed rotation to spread the coating liquid dropped onto the wafer evenly. However, during this process, some coating liquid is thrown off the wafer edge and impacts the inner wall of the outer collection bowl at high speed.

[0003] In existing technologies, the main function of the collection bowl is to collect and guide these waste liquids, discharging them through the drain pipe at the bottom. However, the inventors discovered that due to the viscosity and velocity of the coating liquid, it is prone to rebound (splashing) after impacting the vertical or near-vertical bowl wall. The rebounded droplets may fall back onto the rotating wafer surface, forming local thickness anomalies, streaks, or particle defects, which is known as secondary contamination and seriously affects the accuracy of subsequent photolithography patterns and product yield. Summary of the Invention

[0004] The purpose of this invention is to provide a device for preventing secondary contamination of wafer coatings, thereby overcoming the shortcomings of the prior art.

[0005] To achieve the above objectives, the present invention provides the following technical solution: a device for preventing secondary contamination of wafer coating, comprising a base frame and a rotating chuck for rotating and carrying the wafer, and a lifting frame vertically slidably connected to the base frame and an anti-splash assembly disposed on the lifting frame. The anti-splash assembly comprises: a collection bowl fixedly connected to the lifting frame, the inner cavity of the collection bowl surrounding the rotating chuck and used to collect scattered coating liquid; and an anti-rebound structure comprising a main body sleeve fixedly connected to the collection bowl, the main body sleeve having a hollow cavity and a guide cavity that is narrower at the top and wider at the bottom, an annular edge being provided between the narrow end of the guide cavity and the bottom of the hollow cavity, the annular edge being used to prevent coating liquid ejected onto the inner wall of the guide cavity from rebounding onto the wafer.

[0006] Preferably, the bottom of the hollow cavity extends into the guide cavity, and the annular edge is fixedly connected to the bottom of the hollow cavity.

[0007] Preferably, the annular edge is flared.

[0008] Preferably, a drainage frustum located inside the inner cavity is fixedly connected to the base frame.

[0009] Preferably, the guide cavity is connected to the inner cavity, and the coating liquid ejected onto the inner wall of the guide cavity is guided into the inner cavity for collection.

[0010] Preferably, the base frame is equipped with a lifting cylinder, and the telescopic end of the lifting cylinder is fixedly connected to the lifting frame.

[0011] Preferably, the base frame is equipped with a drive motor, and the output shaft of the drive motor is fixedly connected to the rotating chuck via a transmission shaft.

[0012] Preferably, the collection bowl is fixedly connected to multiple discharge pipes, and the multiple discharge pipes are distributed in a circumferential array on the collection bowl.

[0013] Preferably, while the rotating chuck rotates the wafer below the annular edge and coats it, the anti-rebound structure causes the coating liquid that splashes from the wafer to interact with the solvent, and then flow down along the inner wall of the collection bowl and be discharged.

[0014] In the above technical solution, the present invention provides a device for preventing secondary contamination of wafer coatings. During operation, the piston rod of the lifting cylinder retracts, raising the lifting frame and the entire anti-splash assembly, allowing the operator to place the wafer onto the rotating chuck. Subsequently, the piston rod of the lifting cylinder extends, pushing the anti-splash assembly downwards until the lower surface of the annular edge is slightly higher than the upper surface of the wafer. At this time, the drive motor starts, causing the wafer to rotate at high speed, while simultaneously supplying the nozzle with coating liquid. The splashed coating liquid impacts the inner wall of the conical guide cavity, where most of its kinetic energy is absorbed and flows downwards along the wall. A few rebounding droplets with a large vertical upward component are directly impacted and blocked by the bottom surface of the annular edge as they move upwards. The blocked droplets adhere to the bottom surface of the edge, accumulate into droplets, and then drip downwards, eventually being discharged from the system along with other waste liquids through multiple discharge pipes at the bottom of the collection bowl.

[0015] Among them, through ingenious mechanical structure design, the anti-rebound structure of the ring edge is used to fundamentally block the rebound path, which is highly reliable and easy to maintain.

[0016] Meanwhile, the collection bowl is height-adjustable, greatly facilitating the loading and unloading of wafers and improving the automation level and production capacity of the equipment. Furthermore, the integrated design of the anti-rebound structure and collection bowl requires minimal modification to existing equipment and has low implementation costs. Finally, the top-narrow, bottom-wide guide cavity effectively collects and initially guides splash droplets, and combined with the blocking effect of the annular edge, the anti-contamination effect is significant. Attached Figure Description

[0017] To more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments recorded in this invention. For those skilled in the art, other drawings can be obtained based on these drawings.

[0018] Figure 1This is a schematic diagram of the overall structure provided for an embodiment of the present invention; Figure 2 This is a schematic diagram of the internal structure provided in an embodiment of the present invention; Figure 3 This is a schematic diagram of the drive cylinder structure provided in an embodiment of the present invention; Figure 4 This is a schematic diagram of the anti-rebound structure provided in an embodiment of the present invention; Figure 5 Provided for embodiments of the present invention Figure 4 A magnified view of A in the middle.

[0019] Explanation of reference numerals in the attached figures: 1. Base frame; 2. Wafer; 3. Rotary chuck; 4. Lifting frame; 5. Collection bowl; 6. Main body sleeve; 7. Hollow cavity; 8. Guide cavity; 9. Annular edge; 10. Drainage frustum; 11. Lifting cylinder; 12. Drive motor; 13. Discharge pipe; 14. Drive shaft; 15. Inner cavity. Detailed Implementation

[0020] To enable those skilled in the art to better understand the technical solution of the present invention, the present invention will be further described in detail below with reference to the accompanying drawings.

[0021] Please see Figure 1-5 This invention provides a device for preventing secondary contamination of wafer coatings, comprising a base frame 1 and a rotating chuck 3 for rotating and supporting a wafer 2, a lifting frame 4 vertically slidably connected to the base frame 1, and an anti-splash assembly disposed on the lifting frame 4. The anti-splash assembly includes: a collection bowl 5 fixedly connected to the lifting frame 4, the inner cavity 15 of the collection bowl 5 surrounding the rotating chuck 3 and used to collect scattered coating liquid; and an anti-rebound structure, comprising a main sleeve 6 fixedly connected to the collection bowl 5, the main sleeve 6 having a hollow cavity 7 and a guide cavity 8 that is narrow at the top and wide at the bottom, an annular edge 9 being provided between the narrow end of the guide cavity 8 and the bottom of the hollow cavity 7, the annular edge 9 being used to prevent coating liquid ejected onto the inner wall of the guide cavity 8 from rebounding onto the wafer 2.

[0022] The bottom of the hollow cavity 7 extends into the guide cavity 8, and the annular edge 9 is fixedly connected to the bottom of the hollow cavity 7.

[0023] The annular edge 9 is flared.

[0024] The base frame 1 is fixedly connected to a drainage frustum 10 located in the inner cavity 15.

[0025] The guide cavity 8 is connected to the inner cavity 15, and the coating liquid ejected onto the inner wall of the guide cavity 8 is guided into the inner cavity 15 for collection.

[0026] The base frame 1 is equipped with a lifting cylinder 11, and the telescopic end of the lifting cylinder 11 is fixedly connected to the lifting frame 4.

[0027] The base frame 1 is equipped with a drive motor 12, and the output shaft of the drive motor 12 is fixedly connected to the rotating chuck 3 through the transmission shaft 14.

[0028] The collection bowl 5 is fixedly connected to multiple discharge pipes 13, and the discharge pipes 13 are arranged in a circular array on the collection bowl 5.

[0029] In this process, the rotating chuck 3 drives the wafer 2, which is below the annular edge 9, to rotate and coat the wafer. At the same time, the anti-rebound structure causes the coating liquid that flies out from the wafer 2 to interact with the solvent and flow down along the inner wall of the cavity of the collection bowl 5 and be discharged.

[0030] Based on the above, in a preferred embodiment of the present invention, a nozzle for applying coating liquid to the wafer 2 is further provided on the base frame 1.

[0031] Specifically, during operation, the piston rod of the lifting cylinder 11 retracts, raising the lifting frame 4 and the entire anti-splash assembly, allowing the operator to place the wafer 2 onto the rotating chuck 3. Subsequently, the piston rod of the lifting cylinder 11 extends, pushing the anti-splash assembly downwards until the lower surface of the annular edge 9 is slightly higher than the upper surface of the wafer 2 by approximately 1-5 mm. At this point, the drive motor 12 starts, causing the wafer 2 to rotate at high speed, while simultaneously supplying the nozzle with the coating liquid. The splashed coating liquid impacts the inner wall of the conical guide cavity 8, where most of its kinetic energy is absorbed and flows downwards along the wall. A few rebounding droplets with a larger vertical upward component are directly impacted and blocked by the bottom surface of the annular edge 9 as they move upwards. The blocked droplets adhere to the bottom surface of the edge, accumulate into droplets, and then drip downwards, eventually being discharged from the system along with other waste liquid through multiple discharge pipes 13 at the bottom of the collection bowl 5.

[0032] The foregoing has only described certain exemplary embodiments of the present invention by way of illustration. Undoubtedly, those skilled in the art can modify the described embodiments in various ways without departing from the spirit and scope of the present invention. Therefore, the foregoing drawings and descriptions are illustrative in nature and should not be construed as limiting the scope of protection of the claims of the present invention.

Claims

1. A device for preventing secondary contamination of wafer coating, comprising a base frame (1) and a rotating chuck (3) for rotating and carrying a wafer (2), characterized in that, It also includes a lifting frame (4) vertically slidably connected to the base frame (1) and a splash-proof assembly disposed on the lifting frame (4), the splash-proof assembly comprising: A collection bowl (5) is fixedly connected to a lifting frame (4). The inner cavity (15) of the collection bowl (5) surrounds the rotating chuck (3) and is used to collect the scattered coating liquid. The anti-rebound structure includes a main sleeve (6) fixedly connected to the collection bowl (5), and the main sleeve (6) has a hollow cavity (7) and a guide cavity (8) that is narrow at the top and wide at the bottom. An annular edge (9) is provided between the narrow end of the guide cavity (8) and the bottom of the hollow cavity (7). The annular edge (9) is used to prevent the coating liquid ejected onto the inner wall of the guide cavity (8) from rebounding onto the wafer (2).

2. The device for preventing secondary contamination of the coating on a wafer (2) according to claim 1, characterized in that, The bottom of the hollow cavity (7) extends into the guide cavity (8), and the annular edge (9) is fixedly connected to the bottom of the hollow cavity (7).

3. The device for preventing secondary contamination of the coating on a wafer (2) according to claim 1, characterized in that, The annular edge (9) is flared.

4. The device for preventing secondary contamination of the coating on a wafer (2) according to claim 1, characterized in that, A drainage frustum (10) located in the inner cavity (15) is fixedly connected to the base frame (1).

5. The device for preventing secondary contamination of the coating on a wafer (2) according to claim 1, characterized in that, The guide cavity (8) is connected to the inner cavity (15), and the coating liquid ejected onto the inner wall of the guide cavity (8) is guided to the inner cavity (15) for collection.

6. The device for preventing secondary contamination of the coating on a wafer (2) according to claim 1, characterized in that, The base frame (1) is equipped with a lifting cylinder (11), and the telescopic end of the lifting cylinder (11) is fixedly connected to the lifting frame (4).

7. The device for preventing secondary contamination of the coating on a wafer (2) according to claim 1, characterized in that, The base frame (1) is equipped with a drive motor (12), and the output shaft of the drive motor (12) is fixedly connected to the rotating chuck (3) through the transmission shaft (14).

8. The device for preventing secondary contamination of the coating on a wafer (2) according to claim 1, characterized in that, Multiple discharge pipes (13) are fixedly connected to the collection bowl (5), and the discharge pipes (13) are arranged in a circular array on the collection bowl (5).

9. The device for preventing secondary contamination of the coating on a wafer (2) according to claim 1, characterized in that, While the rotating chuck (3) rotates the wafer (2) below the annular edge (9) and coats it, the coating liquid that flies out from the wafer (2) interacts with the solvent through the anti-rebound structure and flows down and is discharged along the inner wall of the cavity of the collection bowl (5).

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