Developing device capable of preventing backflow of developer

Abstract

A developing device capable of preventing backflow of developing solution, comprising a vacuum suction head, a baffle, a drainage structure, a negative pressure pipe, a retainer rail, a retainer, a push rod and a distance sensor; the vacuum suction head is installed on a motor shaft; the motor and the baffle are fixed above a base; the drainage structure is installed on the upper surface of the baffle; the rear end of the negative pressure pipe is connected with the opening on the upper surface of the baffle; the retainer rail is installed in the groove on the top end of the baffle; the retainer is connected with the upper surface of the retainer rail; and the distance sensor is located above a wafer. The developing device has the following advantages: the negative pressure suction force of the original vacuum suction head of the equipment is ingeniously utilized to drain and collect the excess developing solution, thereby preventing the developing solution from flowing into the back of the wafer and ensuring the safety of the process; the drainage process of the developing solution can be automatically and real-timely adjusted throughout the process, so that the adjustment is more accurate and reliable; the drainage effect of the developing solution is enhanced by adopting the double-layer protection of the drainage structure and the retainer with an inclined surface, thereby better ensuring the safety of the equipment.

Description

Technical Field

[0001] This invention relates to the field of wafer manufacturing, and more particularly to a developing apparatus that prevents backflow of developing solution. Background Technology

[0002] Wafers are the primary raw material for semiconductor chips. Wafer production is a fundamental and crucial component of the semiconductor industry. The raw material for wafers is silicon, and wafer fabrication typically employs a single-crystal vertical growth method. This involves growing high-purity polycrystalline silicon onto a daughter crystal to form a cylindrical silicon rod, which is then polished and sliced ​​to form a preliminary wafer. Before the wafer is diced into wafers, it undergoes coating, exposure, and development processes. The development process, in particular, uses a developing solution to develop the pattern transferred onto the photosensitive material; the quality of this developed pattern significantly impacts subsequent processes and the final product.

[0003] During wafer development, developer often accidentally flows onto the back of the wafer due to factors such as vacuum suction head misalignment, uneven developer distribution, and unstable wafer rotation, affecting wafer quality. If not addressed promptly, this developer can continue to flow into the motor housing, suction head, and even the motor itself, leading to more serious consequences.

[0004] To address these issues, most coating machines on the market currently use baffles or retaining rings to prevent developer from flowing in. However, some existing improved designs can better meet these requirements. For example, a developing apparatus for preventing backside contamination of wafers, disclosed in Chinese patent literature (CN204903943U), includes a rotating baffle that can move up, down, left, and right, and a retaining ring that moves with the rotating baffle. By changing the installation method of the internal rotating baffle, and using the telescopic movement of the vertical and horizontal plates to move the internal rotating baffle, the gap between the retaining ring and the wafer is eliminated. This prevents contamination of the wafer, internal rotating baffle, and vacuum column caused by developer flowing in from the wafer surface, thus improving product yield.

[0005] This design uses a movable rotating baffle to adjust the gap between the retainer ring and the wafer, which can block some of the developer. However, contact will occur between the retainer ring and the wafer. As the wafer rotates around its axis while the retainer ring is fixed with the rotating baffle, friction will inevitably occur, causing damage to the wafer. Adjusting the position of the retainer ring by the movable rotating baffle may cause the retainer ring to pull the baffle back due to its own elasticity, resulting in the retainer ring and the wafer not being on the same horizontal plane, affecting the blocking effect. The adjustment of the baffle is manual and real-time, and it is very difficult to ensure the precision of manual adjustment during wafer rotation. Summary of the Invention

[0006] This invention aims to overcome the safety and reliability issues of existing technologies by providing a developing device that can automatically adjust and remove excess developer. It utilizes the negative pressure of the vacuum suction head itself to promptly drain excess developer, preventing contamination of the equipment and the back side of the wafer.

[0007] To solve the above problems, the present invention adopts the following technical solution.

[0008] A developing device for preventing developer backflow includes a vacuum suction head, a baffle, a drainage structure, a negative pressure tube, a protective ring guide rail, a protective ring, a push rod, a distance sensor, and a wafer. The vacuum suction head is mounted on a motor shaft, and the motor shaft and a corresponding motor are fixed above a base. The baffle is fixed above the base. The drainage structure is mounted on the upper surface of the baffle. The front end of the negative pressure tube is connected to the middle section of the drainage structure, and the rear end is connected to an opening on the top of the baffle. The protective ring guide rail is installed in a groove at the top of the baffle. The protective ring is connected to the upper surface of the protective ring guide rail, and its lower end lightly touches the outer side of the top of the baffle. The push rod is located on the outer side of the circumference corresponding to the drainage structure. The distance sensor is located above the wafer and fixed to a top cover.

[0009] Preferably, the vacuum suction head is positioned below the lower surface of the wafer, forming a negative air pressure layer between them, and they do not directly contact each other under normal circumstances; sufficient gaps are left between the suction head and the wafer to prevent damage to the wafer structure caused by suction.

[0010] Preferably, the drainage structure consists of four groups, evenly distributed along the circumference, and includes a guide head, a support, a conduit, and a reservoir. When the drainage structure is not in operation, it is located outside the wafer. When the developer is too much and causes the wafer to tilt, the drainage structure corresponding to the tilt direction is pushed by the push rod to be closer to the wafer for drainage.

[0011] Preferably, the flow guide head is positioned horizontally above the lower surface of the wafer; the support is fixed to the upper surface of the baffle; the liquid storage tank is connected to the end of the conduit and placed on the base platform; the various parts of the flow guide structure generally do not contact the wafer surface, and occasional slight contact only affects the outer ring of the wafer that is not made into a wafer, which can better avoid damage to the wafer.

[0012] Preferably, the front end of the negative pressure tube has a short vertically upward bend, the bottom of which is no higher than the rear end of the negative pressure tube. The negative pressure tube uses the suction force of the vacuum suction head to assist in drawing the developer. Since the negative pressure tube is directly connected to the internal negative pressure space where the vacuum suction head is located, the bend can prevent the developer from flowing back into the vacuum suction head and the motor, thus making use of existing conditions and ensuring safe use.

[0013] Preferably, the retaining ring guide rail consists of a retaining ring cover, a ball bearing disk, and a retaining ring base; the retaining ring cover and the retaining ring base have the same structure, and their internal concave arc surfaces are in close contact with the ball bearing disk; when the wafer touches and rotates with the retaining ring, the retaining ring and the retaining ring guide rail rotate with the wafer, avoiding damage to the back of the wafer caused by sliding friction.

[0014] Preferably, the retaining ring is made of a material with high plasticity, with a sloping top that is higher on the inside and lower on the outside, and the sloping angle is between 30 and 60 degrees. For developer that has not been completely drained by the drainage structure, the retaining ring is needed as an auxiliary drainage structure. The sloping design of the retaining ring helps the developer to flow down the slope according to its own tension and gravity, which is better than the usual flat design.

[0015] Preferably, the negative pressure tube, push rod, distance sensor, and drainage structure are the same in number and arrangement; the push rod and distance sensor are both connected to the controller; since the push rod and distance sensor are both arranged on the housing or base, the controller can be connected by wired or wireless signal connection.

[0016] Therefore, the present invention has the following beneficial effects: (1) It cleverly utilizes the negative pressure suction of the original vacuum suction head of the equipment to drain and collect excess developer, preventing developer from flowing into the back of the wafer and ensuring process safety. (2) The developer drainage process can be automatically adjusted in real time throughout the entire process, making the adjustment more precise and reliable. (3) The use of a drainage structure and a double-layer protection with a beveled guard ring enhances the drainage effect of the developer, thereby better ensuring equipment safety. Attached Figure Description

[0017] Figure 1 This is a schematic diagram of the overall structure of the present invention; Figure 2 This is a schematic diagram of the drainage structure of the present invention; Figure 3 This is a structural schematic diagram of the protective ring and the protective ring guide rail of the present invention; In the diagram: 1-vacuum suction head, 2-baffle, 3-drainage structure, 31-guide head, 32-support part, 33-conduit, 34-liquid storage tank, 4-negative pressure tube, 5-protective ring guide rail, 51-protective ring cover, 52-ball bearing disc, 53-protective ring base, 6-protective ring, 7-push rod, 8-distance sensor, 9-wafer. Detailed Implementation

[0018] The embodiments of the present invention will be further described below through specific examples and in conjunction with the accompanying drawings.

[0019] like Figures 1-3As shown, the present invention relates to a developing device for preventing backflow of developer, comprising a vacuum suction head 1, a baffle 2, a drainage structure 3, a negative pressure tube 4, a protective ring guide rail 5, a protective ring 6, a push rod 7, a distance sensor 8, and a wafer 9; the vacuum suction head 1 is mounted on a motor shaft, and the motor shaft and a corresponding motor are fixed above a base; the baffle 2 is fixed above the base; the drainage structure 3 is mounted on the upper surface of the baffle 2; the front end of the negative pressure tube 4 is connected to the middle section of the drainage structure 3, and the rear end is connected to the opening at the top of the baffle 2; the protective ring guide rail 5 is mounted in the groove at the top of the baffle 2; the protective ring 6 is connected to the upper surface of the protective ring guide rail 5, and its lower end lightly touches the outer side of the top of the baffle 2; the push rod 7 is located on the outer side of the circumference corresponding to the drainage structure 3; the distance sensor 8 is located above the wafer 9 and is fixed on the top cover.

[0020] Specifically, the vacuum suction head 1 is lower than the lower surface of the wafer 9, forming an air negative pressure layer between it and the wafer 9, and does not directly contact each other under normal circumstances.

[0021] Specifically, the drainage structure 3 consists of 4 groups, evenly distributed along the circumference, and includes a guide head 31, a support 32, a conduit 33, and a liquid storage tank 34.

[0022] Specifically, the guide head 31 is positioned horizontally above the lower surface of the wafer 9; the support part 32 is fixed to the upper surface of the baffle 2; and the liquid storage tank 34 is connected to the end of the conduit 33 and placed on the base platform.

[0023] Specifically, the front end of the negative pressure pipe 4 has a short vertically upward bend, and the bottom of the bend is not higher than the rear end height of the negative pressure pipe 4.

[0024] Specifically, the guard ring guide rail 5 is composed of a guard ring cover 51, a ball bearing disc 52 and a guard ring base 53; the guard ring cover 51 and the guard ring base 53 have the same structure, and their internal concave arc surfaces are tightly fitted with the ball bearing disc 52.

[0025] Specifically, the protective ring 6 is made of a material with high plasticity, with a sloping top that is higher on the inside and lower on the outside, and the sloping angle is between 30 and 60 degrees.

[0026] Specifically, the negative pressure tube 4, push rod 7, distance sensor 8 and drainage structure 3 are in the same quantity and arrangement; the push rod 7 and distance sensor 8 are both connected to the controller.

[0027] The working process of this invention is as follows.

[0028] like Figures 1-3As shown, during operation, the vacuum suction head and motor start; the motor drives the vacuum suction head to rotate, and the vacuum suction head picks up the wafer, forming a negative pressure air layer between them; the retaining ring, retaining ring guide rail, and wafer rotate with the vacuum suction head, while the developer is injected from above towards the center of the wafer for development. When the developer on one side increases, causing the wafer to tilt, the distance sensor detects the tilt signal, and the controller drives one or more corresponding push rods to push out the drainage structure close to the wafer, using the negative pressure of the device itself to drain the developer; during the drainage process, most of the developer that caused the wafer to shift flows into the storage tank along the guide tube, and some developer flows to the back of the wafer, flows along the inclined surface of the retaining ring towards the baffle to avoid the motor and vacuum suction head, and finally flows to the base platform originally used to collect waste liquid. After the wafer position returns to horizontal, the distance sensor detects the signal, and the controller drives the corresponding push rod to retract and end the drainage process. During the wafer development process, the above process can be automatically repeated multiple times until the development process is complete.

[0029] The above embodiments are only used to further illustrate a developing device that can prevent backflow of developing solution according to the present invention. However, the present invention is not limited to the embodiments. Any simple modifications, equivalent changes and alterations made to the above embodiments based on the technical essence of the present invention shall fall within the protection scope of the technical solution of the present invention.

Claims

1. A developing apparatus for preventing backflow of developing solution, characterized in that: The device includes a vacuum suction head (1), a baffle (2), a drainage structure (3), a negative pressure tube (4), a protective ring guide rail (5), a protective ring (6), a push rod (7), a distance sensor (8), and a wafer (9). The vacuum suction head (1) is mounted on a motor shaft, and the motor shaft and the corresponding motor are fixed above the base. The baffle (2) is fixed above the base. The drainage structure (3) is mounted on the upper surface of the baffle (2). The front end of the negative pressure tube (4) is connected to the middle section of the drainage structure (3), and the rear end is connected to the opening above the baffle (2). The protective ring guide rail (5) is mounted in the groove at the top of the baffle (2). The protective ring (6) is connected to the upper surface of the protective ring guide rail (5), and its lower end lightly touches the outer side of the top of the baffle (2). The push rod (7) is set on the outer side of the circumference corresponding to the drainage structure (3). The distance sensor (8) is located above the wafer (9) and fixed on the top cover. The flow-guiding structure (3) comprises a flow guide head (31), a support part (32), a conduit (33), and a liquid storage tank (34). The flow guide head (31) is horizontally positioned above the lower surface of the wafer (9). The support part (32) is fixed to the upper surface of the baffle (2).

2. The developing apparatus according to claim 1, characterized in that: The vacuum suction head (1) is below the lower surface of the wafer (9) and forms an air negative pressure layer between it and the wafer (9).

3. A developing apparatus for preventing backflow of developer according to claim 1, characterized in that: The drainage structure (3) consists of 4 groups, which are evenly distributed along the circumference. When the drainage structure is not working, it is located on the outside of the wafer. When the developer is too much and causes the wafer to tilt, the drainage structure in the corresponding tilt direction is pushed by the push rod to the direction close to the wafer for drainage.

4. A developing apparatus for preventing backflow of developing solution according to claim 3, characterized in that: The liquid storage tank (34) is connected to the end of the conduit (33) and placed on the base platform.

5. A developing apparatus for preventing backflow of developer according to claim 1, characterized in that: The front end of the negative pressure tube (4) has a short vertically upward bend, the bottom of which is not higher than the rear end of the negative pressure tube (4), and the negative pressure tube is directly connected to the internal negative pressure space where the vacuum suction head is located.

6. A developing apparatus for preventing backflow of developer according to claim 1, characterized in that: The protective ring guide rail (5) consists of a protective ring cover (51), a ball bearing disk (52), and a protective ring base (53). The inner recess of the protective ring cover (51) and the protective ring base (53) have the same structure, and the recessed arc surface is in close contact with the ball bearing disk (52). When the wafer touches and rotates with the protective ring, the protective ring and the protective ring guide rail rotate with the wafer.

7. A developing apparatus for preventing backflow of developer according to claim 1, characterized in that: The protective ring (6) is made of plastic material, with a sloping top that is higher on the inside and lower on the outside, and the sloping angle is between 30 and 60 degrees.

8. A developing apparatus for preventing backflow of developer according to claim 1, characterized in that: There are four sets of negative pressure tube (4), push rod (7) and distance sensor (8), and the arrangement of each set is adapted to the drainage structure (3); the push rod (7) and distance sensor (8) are both connected to the controller.

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