Device for uniformly spin-coating photoresist

Abstract

The utility model provides a photoresist uniform spin-coating device which comprises a coating cylinder with an opening at the upper end; the turntable is horizontally arranged in the coating cylinder, and the chip is coaxially placed at the upper end of the turntable; the upper end of the rotating shaft is fixedly connected with the lower end of the turntable, and the lower end of the rotating shaft is fixedly connected with the driving end of the motor; the glue pipes are vertically arranged, the number of the glue pipes is more than two, the glue pipes are arranged at intervals, and the photoresist is dropwise added to the upper end face of the chip by the glue pipes; wherein one rubber tube is right opposite to the circle center position of the chip; when the number of the rubber tubes is two, a distance is formed between the other rubber tube and the circle center of the chip; when the number of the rubber tubes is more than two, the distance between the remaining rubber tubes and the circle center of the chip is gradually increased; and the flow of the photoresist output by the photoresist tube is gradually reduced from the central position of the chip to the outer side. Through the multi-rubber-tube gradient distribution design and flow decreasing control, the influence that centrifugal force is increased along with the radius is effectively compensated, and the defects that the center is thin and the edge is thick in a traditional spin-coating process are overcome.

Description

Technical Field

[0001] This utility model relates to the field of spin coating equipment technology, specifically a photoresist uniform spin coating device. Background Technology

[0002] In semiconductor manufacturing processes, photoresist coating is one of the key steps in chip manufacturing. Currently, the industry commonly uses spin coating to uniformly coat the photoresist onto the surface of a wafer or chip. The specific process involves placing a droplet of photoresist at the center of the chip, then rotating the chip at high speed, using centrifugal force to spread the photoresist outwards, ultimately covering the entire chip surface.

[0003] However, traditional spin coating processes have a significant technical drawback: uneven thickness distribution of the photoresist film, typically exhibiting a thinner central area and a thicker edge area. This unevenness is mainly caused by the following factors:

[0004] 1. During spin coating, the centrifugal force increases with the radius, making the accumulation of photoresist more significant in the edge region.

[0005] 2. When the photoresist flows outward, the photoresist in the central area is exhausted earlier, while the edge area tends to form a thicker photoresist layer due to inertia.

[0006] Uneven photoresist film thickness can affect subsequent photolithography accuracy, leading to pattern transfer distortion and even reducing chip yield and performance. Although existing technologies attempt to improve uniformity by optimizing rotation speed, resist viscosity, or pre-coating processes, the effects are limited, especially for large-size wafers or high-precision processes, where the problem is more pronounced.

[0007] Therefore, there is an urgent need to develop a new type of photoresist coating device to achieve a more uniform film thickness distribution, thereby improving the process stability and product reliability of semiconductor manufacturing. Utility Model Content

[0008] To address the technical problems in the background art, this utility model discloses a photoresist uniform spin coating device.

[0009] This utility model provides a photoresist uniform spin coating device, comprising:

[0010] A covering tube with an opening at the top;

[0011] The turntable is horizontally positioned inside the covering cylinder, with the chip coaxially placed at the top of the turntable;

[0012] The rotating shaft is arranged vertically, with its upper end fixedly connected to the lower end of the turntable and its lower end fixedly connected to the drive end of the motor.

[0013] The photoresist tubes are arranged vertically, with two or more tubes spaced apart. The photoresist is applied to the upper surface of the chip through the tubes. One tube is positioned directly opposite the center of the chip. When there are two tubes, there is a gap between the other tube and the center of the chip. When there are more than two tubes, the distance between the remaining tubes and the center of the chip increases. The flow rate of photoresist output from the tubes decreases from the center of the chip outwards.

[0014] Furthermore, it also includes a vacuum adsorption structure, which adsorbs the lower side of the chip.

[0015] Furthermore, the vacuum adsorption structure includes adsorption holes penetrating the upper and lower sides of the turntable, and also includes an inner cavity communicating with the adsorption holes and disposed inside the rotating shaft; the inner cavity is provided with an air extraction hole communicating with the inlet of the vacuum pump.

[0016] Furthermore, a rotatably connected air box is sleeved on the outside of the rotating shaft; the air box and the rotating shaft form a closed air chamber that communicates with the air extraction port; the air box is connected to a connector, which connects the air chamber and the inlet of the vacuum pump.

[0017] Furthermore, an upper limit plate is fixedly connected to the rotating shaft; a lower limit plate is also threadedly connected to the rotating shaft; the air box is sandwiched between the upper limit plate and the lower limit plate.

[0018] Furthermore, rolling balls are engaged on the opposite sides of the upper and lower limit plates; the rolling balls abut against the air box and are movably connected to the air box.

[0019] Furthermore, a locking nut is threaded onto the rotating shaft; the upper end of the locking nut is close to the lower end of the lower limit plate.

[0020] Furthermore, the inner wall of the coating cylinder is provided with adhesive tape; the width and position of the adhesive tape are configured such that the photoresist splashed during spin coating is absorbed by the adhesive tape.

[0021] The beneficial effects of this utility model are:

[0022] 1. By using a multi-tube gradient distribution design and flow rate reduction control, the effect of centrifugal force increasing with radius is effectively compensated, overcoming the defect of "thin center and thick edge" in traditional spin coating process.

[0023] 2. Configure the number of tubes according to the diameter of the chip to improve spin coating efficiency and quality.

[0024] 3. During spin coating, the inner photoresist only needs to diffuse to the outer photoresist, thereby shortening the diffusion distance of the photoresist, shortening the spin coating time, and improving the efficiency of spin coating. Attached Figure Description

[0025] The present invention will be further described below with reference to the accompanying drawings and embodiments.

[0026] Figure 1 This is a schematic diagram of the structure of this utility model, in which a chip is assembled;

[0027] Figure 2 This is a schematic diagram of the structure of this utility model;

[0028] Figure 3 This is a schematic diagram of the connection structure between the turntable and the shaft;

[0029] Figure 4 This is a top view of the connection structure between the turntable and the shaft;

[0030] Figure 5 yes Figure 4 Sectional view of AA;

[0031] Figure 6 yes Figure 5 Enlarged view of point B in the middle;

[0032] Figure 7 yes Figure 5 Enlarged view of point C in the middle;

[0033] In the diagram: 1. Coating cylinder; 2. Turntable; 3. Chip; 4. Shaft; 5. Adhesive tube; 6. Air box; 7. Air chamber; 8. Connector; 9. Upper limit plate; 10. Lower limit plate; 11. Ball bearing; 12. Locking nut; 13. Adhesive tape; 14. Regulating valve; 15. Ball valve; 16. Delivery pipe; 17. Spray nozzle; 18. First sealing ring; 19. Second sealing ring; 21. Adsorption hole; 22. Slot; 41. Inner cavity; 42. Air extraction hole; 43. Snap-fit ​​part; 44. Snap-fit ​​plate. Detailed Implementation

[0034] The present invention will now be described in further detail with reference to the accompanying drawings. These drawings are simplified schematic diagrams, illustrating only the basic structure of the present invention, and therefore only show the components relevant to the present invention.

[0035] like Figure 1-4 As shown, this utility model discloses a photoresist uniform spin coating device, including a cylindrical coating cylinder 1 with its axis arranged vertically. The coating cylinder 1 consists of a cylindrical body and a ring-shaped connecting plate disposed at the lower end of the body. The connecting plate is fixed to a support by bolts.

[0036] A horizontally arranged turntable 2 is provided inside the coating cylinder 1, and the chip 3 is coaxially placed on the upper end of the turntable 2. Multiple grooves are provided on the upper surface of the turntable 2 to facilitate the placement and removal of the chip 3. In this embodiment, the diameter of the chip 3 is 300mm, which is larger than the diameter of the turntable 2.

[0037] The lower end of the turntable 2 is clamped with a coaxially arranged rotating shaft 4. The lower end of the rotating shaft 4 is fixedly connected to the drive end of the motor through a coupling. The motor is fixedly mounted on the bracket to drive the turntable 2 to rotate.

[0038] The specific snap-fit ​​structure between turntable 2 and shaft 4 is as follows: Figure 7 As shown, the lower end of the turntable 2 has a coaxially arranged slot 22. The upper end of the rotating shaft 4 is provided with a snap-fit ​​part 43 and a snap-fit ​​plate 44 forming a shoulder; the snap-fit ​​part 43 snaps into the slot 22, and the snap-fit ​​plate 44 abuts against the lower end face of the turntable 2. Bolts pass through the snap-fit ​​plate 44 and are threadedly connected to the turntable 2.

[0039] This invention also includes a vacuum adsorption structure for adsorbing and fixing the chip 3, improving the positional stability of the chip 3. Specifically, the turntable 2 has four adsorption holes 21 penetrating the upper and lower sides, with the lower ends of the adsorption holes 21 located within the slot 22. The rotating shaft 4 is hollow, forming an inner cavity 41. The upper end of the rotating shaft 4 is open, and the lower end is sealed by a welded sealing plate. The inner cavity 41 covers the adsorption holes 21, allowing the adsorption holes 21 to communicate with the inner cavity 41. A second sealing ring 19 is engaged at the upper end of the engaging part 43, sealing the engaging part 43 to the bottom of the slot 22.

[0040] like Figure 5 and Figure 6 As shown, a plurality of evenly distributed vent holes 42 penetrating the inner and outer sides of the rotating shaft 4 are provided at the middle position of the rotating shaft 4. A horizontally arranged, annular upper limit plate 9 is welded to the outer wall of the rotating shaft 4, located above the vent holes 42. An external thread is provided on the area below the vent holes 42 of the rotating shaft 4, and a lower limit plate 10 is threadedly connected to it. An air box 6, which is fitted onto the rotating shaft 4, is sandwiched between the upper limit plate 9 and the lower limit plate 10. The outer surface of the air box 6 is cylindrical, with its upper and lower ends abutting against the upper limit plate 9 and the lower limit plate 10, respectively. An annular groove is provided inside the air box 6, forming an air cavity 7 covering the vent holes 42 between the annular groove and the outer wall of the rotating shaft 4. First sealing rings 18 are engaged on both sides of the annular groove, sealingly connecting with the outer wall of the rotating shaft 4.

[0041] A locking nut 12 is also threaded onto the rotating shaft 4. The upper end of the locking nut 12 is close to the lower end of the lower limit plate 10 to improve the positional stability of the lower limit plate 10.

[0042] A connection hole for connecting the gas chamber 7 to the outside is provided in the middle of the side of the gas box 6. The connection hole is a threaded hole. One end of the connector 8 is connected to the connection hole, and the other end is connected to the inlet of the vacuum pump. When the vacuum pump is started, a negative pressure is generated at the adsorption hole 21, which adsorbs and fixes the chip 3.

[0043] Both the upper limit plate 9 and the lower limit plate 10 have rolling balls 11 engaged on their opposite sides; the balls 11 abut against and are movably connected to the air box 6. With this configuration, the position of the air box 6 remains unchanged when the shaft 4 rotates, thus preventing the pipes of the connecting joint 8 from becoming tangled.

[0044] This embodiment also includes an L-shaped delivery tube 16, the vertical portion of which is located outside the coating cylinder 1. The lower end of the vertical portion is connected to the drive end of the drive assembly, allowing for rotation and lifting. The horizontal portion is connected to the upper end of the vertical portion and extends directly upwards from the coating cylinder 1. The lower end of the horizontal portion is connected to three spaced-apart adhesive tubes 5, and the lower end of each adhesive tube 5 is equipped with a dispensing head 17 to apply photoresist to the upper surface of the chip 3.

[0045] The tube 5 connected to the end of the horizontal section is positioned directly opposite the center of the chip 3. The remaining tubes 5 are spaced further away from the center of the chip 3 in increasing order and are evenly distributed relative to the chip 3. Each tube 5 is equipped with a ball valve 15 and a regulating valve 14. The ball valve 15 controls the opening and closing of the tube 5, and the regulating valve 14 controls the flow rate of the tube 5. The flow rate of photoresist output from the tube 5 decreases from the center of the chip 3 outwards.

[0046] An adhesive tape 13 is also provided on the inner side of the cylinder, with its adsorption surface facing the chip 3. In this embodiment, the tape 13 is a polyurethane tape. The width and position of the tape 13 are configured such that all photoresist splashed during spin coating is adsorbed by the tape 13. This configuration ensures that excess photoresist is adsorbed onto the tape 13, avoiding environmental pollution. After a certain amount of photoresist adheres to the tape 13, the tape 13 is removed and placed in a photoresist-specific solvent (PGMEA) to dissolve the waste photoresist, achieving harmless treatment.

[0047] Initially, the delivery pipe 16 is located in the outer region of the covering cylinder 1; the operation steps in this embodiment are as follows:

[0048] S1. Open the cover at the top of the coating cylinder 1 and place the chip 3 on the turntable 2;

[0049] S2. Start the vacuum pump and adsorb chip 3;

[0050] S3. Drive the delivery tube 16 to rotate and descend in sequence, so that the glue tube 5 moves to the glue-dispensing position and the outlet at the lower end of the glue nozzle 17 is close to the chip 3.

[0051] S4. Start the delivery pump to allow the spray nozzle 17 to drip photoresist downwards, and simultaneously start the motor to slowly rotate the chip 3 one revolution. The photoresist forms two annular structures and a circular structure in the center on the chip 3; the motor speed is configured such that the amount of photoresist dripped during one revolution of the chip 3 is consistent with the set amount.

[0052] S5. Turn off the delivery pump and motor, move the delivery pipe 16 in the reverse direction to the outside of the covering cylinder 1, and put on the cover;

[0053] S6. Start the motor to complete the spin coating operation.

[0054] Compared to existing technologies, the advantages of this embodiment are: 1. By using a gradient distribution design of multiple adhesive tubes 5 and flow rate reduction control, the influence of centrifugal force as the radius increases is effectively compensated, overcoming the defect of "thin center and thick edge" in traditional spin coating processes. 2. The number of adhesive tubes 5 is configured according to the diameter of the chip 3 to improve spin coating efficiency and quality. 3. During spin coating, the inner photoresist only needs to diffuse to the outer photoresist, thereby shortening the photoresist diffusion distance, shortening the spin coating time, and improving the spin coating efficiency.

[0055] Based on the above-described preferred embodiments of this utility model, and through the foregoing description, those skilled in the art can make various changes and modifications without departing from the technical concept of this utility model. The technical scope of this utility model is not limited to the contents of the specification, but must be determined according to the scope of the claims.

Claims

1. A photoresist uniform spin coating apparatus, characterized in that, include: The covering tube (1) has an opening at its upper end; The turntable (2) is horizontally set inside the covering cylinder (1), and the chip (3) is coaxially placed at the upper end of the turntable (2); The rotating shaft (4) is arranged vertically, with its upper end fixedly connected to the lower end of the turntable (2) and its lower end fixedly connected to the drive end of the motor. Photoresist is applied to the upper surface of the chip (3) by two or more tubes arranged vertically and spaced apart. One tube is positioned directly opposite the center of the chip (3). When there are two tubes, the other tube is spaced apart from the center of the chip (3). When there are more than two tubes, the remaining tubes are spaced further apart from the center of the chip (3). The flow rate of the photoresist output by the tubes decreases from the center of the chip (3) outwards.

2. The photoresist uniform spin coating apparatus according to claim 1, characterized in that: It also includes a vacuum adsorption structure, which adsorbs the lower side of the chip (3).

3. The photoresist uniform spin coating apparatus according to claim 2, characterized in that: The vacuum adsorption structure includes adsorption holes (21) penetrating the upper and lower sides of the turntable (2), and also includes an inner cavity (41) communicating with the adsorption holes (21) and disposed inside the rotating shaft (4); The inner cavity (41) is provided with an air extraction port (42) that communicates with the inlet of the vacuum pump.

4. The photoresist uniform spin coating apparatus according to claim 3, characterized in that: The outer side of the rotating shaft (4) is fitted with a rotatably connected air box (6); The air box (6) and the rotating shaft (4) form a closed air chamber (7) that is connected to the air extraction hole (42); The gas box (6) is connected to a connector (8), which connects the gas chamber (7) and the inlet of the vacuum pump.

5. The photoresist uniform spin coating apparatus according to claim 4, characterized in that: An upper limit plate (9) is fixedly connected to the rotating shaft (4); A lower limit plate (10) is also threadedly connected to the rotating shaft (4); The air box (6) is sandwiched between the upper limit plate (9) and the lower limit plate (10).

6. The photoresist uniform spin coating apparatus according to claim 5, characterized in that: The upper limit plate (9) and the lower limit plate (10) are respectively engaged with rolling balls (11) on their opposite sides; The ball bearing (11) abuts against the air box (6) and is movably connected to the air box (6).

7. The photoresist uniform spin coating apparatus according to claim 5, characterized in that: A locking nut (12) is also threaded onto the rotating shaft (4); The upper end of the locking nut (12) is close to the lower end of the lower limit plate (10).

8. The photoresist uniform spin coating apparatus according to claim 1, characterized in that: The inner wall of the covering cylinder (1) is provided with adhesive tape (13); The width and position of the tape (13) are configured such that the photoresist splashed during spin coating is absorbed by the tape (13).

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