Closed vacuum chemical tank

Abstract

The invention relates to the technical field of semiconductors, in particular to a closed vacuum chemical tank, which can effectively lead out liquid and bubbles adsorbed on a wafer through a vacuumizing design, so that the yield is improved. Comprising a chemical tank body, chemical liquid circulating pipes are connected to the top and the bottom of the chemical tank body respectively, a separator is arranged outside the chemical tank body and forms a closed cavity outside the chemical tank body, a vacuumizing device is connected to the outside of the separator, and the vacuumizing device can suck air in the cavity of the separator outwards. The suction force of the vacuumizing device ranges from-70 kpa to-100 kpa.

Description

Technical Field

[0001] This invention relates to the field of semiconductor technology, and in particular to a sealed vacuum chemical bath. Background Technology

[0002] The wet bench is a key piece of equipment in semiconductor manufacturing used for wafer cleaning and etching. It removes surface contaminants using chemical solutions to ensure wafer cleanliness meets the requirements of subsequent processes. However, traditional wet benches are open chemical tanks. Although a lid is added to the tank during etching to prevent acid gas leakage, it still has the disadvantage of external environmental contamination. Furthermore, bubbles are generated during the reaction between the wafer and the chemicals. These bubbles can adhere to the wafer, leading to uneven etching or development, reducing wafer yield, and affecting production quality. Summary of the Invention

[0003] To overcome the above shortcomings, the present invention provides a closed vacuum chemical bath. This chemical bath can effectively remove liquid and bubbles adsorbed on the wafer through the vacuum design, thereby improving the yield.

[0004] To achieve the above objectives, the present invention adopts the following technical solution: A sealed vacuum chemical bath includes a chemical bath body, with chemical liquid circulation pipes connected to the top and bottom of the chemical bath body. An isolation element is provided outside the chemical bath body, forming a sealed cavity outside the chemical bath body. A vacuum pumping device is connected to the outside of the isolation element, which can draw air out of the cavity of the isolation element. The suction force of the vacuum pumping device is between -70 kPa and -100 kPa.

[0005] Compared with existing technologies, this technical solution has the following technical advantages: In this application, by setting an isolation component on the outside of the traditional chemical tank, a nearly sealed cavity is formed. A vacuum device is used to create a negative pressure inside, drawing air outward. This causes the dissolved gas in the chemical liquid to precipitate and form bubbles. At the same time, the original bubbles expand due to the reduced external pressure, making it easier for them to float to the surface of the liquid and escape. This reduces the possibility of bubbles adhering to the wafer, thereby effectively improving the yield and ensuring production quality.

[0006] As a further description of the above technical solution: the isolation component includes a rectangular outer shell and an end cap covering the top of the outer shell, and the outer shell has mounting holes for the chemical liquid circulation pipe and the vacuum device pipeline to pass through.

[0007] As a further description of the above technical solution: there is a sealing structure between the end cap and the outer shell. The sealing structure includes a concave or convex structure disposed on the top side of the outer shell and a convex or concave structure disposed on the inner side of the end cap. The diameter of the end cap is larger than the diameter of the outer shell. A sealing strip is disposed in the recessed part of the concave structure. When the end cap and the outer shell are fastened together, the sealing strip can abut against the convex structure.

[0008] As a further description of the above technical solution: the chemical tank is a rectangular structure with an opening at the top. A partition is provided in the middle of the chemical tank, a wafer placement rack is provided on the partition, and a flow groove is opened on the partition. The chemical liquid circulation pipe includes an inlet pipe group located below the partition and an outlet pipe group located at the upper end of the chemical tank.

[0009] As a further description of the above technical solution: it also includes a circulation component, wherein the inlet pipe group, the chemical tank, and the outlet pipe group form a circulation of chemical liquid under the action of the circulation component.

[0010] As a further description of the above technical solution: the liquid inlet pipe group includes a main liquid inlet pipe and a U-shaped branch pipe. The middle position of the U-shaped branch pipe is connected to the main liquid inlet pipe, and both ends of the U-shaped branch pipe are closed. Multiple evenly distributed liquid outlet holes are opened on the U-shaped branch pipe. The main liquid inlet pipe is connected to the liquid outlet end of the circulation component.

[0011] As a further description of the above technical solution: one end of the outlet pipe assembly is connected to the inlet end of the circulation component, and the other end is inserted into the upper end of the chemical tank.

[0012] As a further description of the above technical solution: an L-shaped overflow baffle is also provided on the upper outer side of the chemical tank. The inner side of the L-shaped overflow baffle and the outer wall of the chemical tank form an overflow groove. An overflow port is provided at the bottom of the overflow groove. The overflow port is connected to an overflow pipe. The overflow pipe is connected to the circulation component.

[0013] As a further description of the above technical solution: the vacuum pumping device includes a vacuum pumping pipeline and a vacuum pump. The vacuum pump is located outside the isolation component. One end of the vacuum pumping pipeline is connected to the middle of the isolation component, and the other end is connected to the suction port of the vacuum pump. Attached Figure Description

[0014] Figure 1 This is a schematic diagram of the structure of a sealed vacuum chemical tank according to the present invention; Figure 2 This is a schematic diagram of the structure of a sealed vacuum chemical tank after removing the outer shell according to the present invention; Figure 3 This is a cross-sectional view of the chemical tank of the present invention; Figure 4 This is a schematic diagram showing the flow direction of the internal chemical liquid in this invention; Figure 5 This is a schematic diagram of the partition and wafer placement rack in this invention; Figure 6 This is a partial structural diagram of the outer shell and end cap in this invention.

[0015] Legend: 1. Chemical tank body; 2. Outer shell; 3. End cap; 4. Concave structure; 5. Convex structure; 6. Sealing strip; 7. Partition plate; 8. Wafer placement rack; 9. Main inlet pipe; 10. Flow channel; 11. U-shaped branch pipe; 12. Outlet hole; 13. Outlet pipe assembly; 14. L-shaped overflow baffle; 15. Overflow pipeline; 16. Vacuum pipeline; 17. Baffle plate; 18. Baffle bar; 19. Limiting groove. Detailed Implementation

[0016] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0017] Reference Figures 1-6 One embodiment provided by the present invention: A sealed vacuum chemical tank includes a chemical tank body 1, with chemical liquid circulation pipes connected to the top and bottom of the chemical tank body 1. An isolator is disposed outside the chemical tank body 1, forming a sealed cavity. A vacuum pumping device is connected to the outside of the isolator, capable of drawing air out of the cavity within the isolator. The suction power of the vacuum pumping device is between -70 kPa and -100 kPa. In this application, by placing an isolator outside the conventional chemical tank body 1, a near-sealed cavity is formed. The vacuum pumping device creates a negative pressure state inside, drawing air out. This causes dissolved gases in the chemical liquid to precipitate and form bubbles. Simultaneously, the existing bubbles expand due to the reduced external pressure, making them more likely to float and escape from the liquid surface. This reduces the possibility of bubbles adhering to the wafer, effectively improving yield and ensuring production quality.

[0018] In this embodiment: the isolation component includes a rectangular outer shell 2 and an end cap 3 covering the top of the outer shell 2. The outer shell 2 has an installation hole for the chemical liquid circulation pipe and the vacuum device pipe to pass through. The chemical tank 1 is provided with connecting ears on the outside, which are fixed to the bottom of the isolation component.

[0019] In this embodiment, a sealing structure is provided between the end cap 3 and the outer shell 2. The sealing structure includes a concave structure 4 or a convex structure 5 provided on the top side of the outer shell 2 and a convex structure 5 or a concave structure 4 provided on the inner side of the end cap 3. The diameter of the end cap 3 is larger than the diameter of the outer shell 2. A sealing strip 6 is provided in the recessed part of the concave structure 4. When the end cap 3 and the outer shell 2 are fastened together, the sealing strip 6 can abut against the convex structure 5. In this way, the end cap 3 and the outer shell 2 can play a sealing role, reduce air leakage of the isolation component, and ensure the air extraction effect.

[0020] In this embodiment: the chemical tank 1 is a rectangular structure with an opening at the top. A partition 7 is provided in the middle of the chemical tank 1, and a wafer placement rack 8 is provided on the partition 7. A flow channel 10 is provided on the partition 7. The chemical liquid circulation pipe includes an inlet pipe group located below the partition 7 and an outlet pipe group 13 located at the upper end of the chemical tank 1. In this way, by introducing liquid below the partition 7, the chemical liquid moves upward inside the chemical tank 1, passes through the flow channel 10, and reacts with the wafers on the wafer placement rack 8. Due to the upward movement, the bubbles generated by the reaction can be pushed upward, accelerating the removal of bubbles and further ensuring the yield rate. A baffle is provided on the inner wall of the chemical tank 1, and the partition 7 is placed on the baffle. Under the action of gravity, it is prevented from entering the chemical tank 1.

[0021] In this embodiment, a circulation component is also included. The inlet pipe group, chemical tank 1, and outlet pipe group 13 form a circulation of chemical liquid under the action of the circulation component. In this way, the circulation direction from bottom to top can push the bubbles upward and improve the effect of bubble removal.

[0022] In this embodiment, the circulation component includes a circulation pump and a chemical liquid tank. The circulation pump draws the chemical liquid from the chemical liquid tank into the inlet pipe group and injects it into the chemical tank 1 for reaction. The chemical liquid in the outlet pipe group 13 and the overflow pipe 15 is discharged back into the chemical liquid tank to generate circulation.

[0023] In this embodiment, the liquid inlet pipe assembly includes a main liquid inlet pipe 9 and a U-shaped branch pipe 11. The middle position of the U-shaped branch pipe 11 is connected to the main liquid inlet pipe 9, and both ends of the U-shaped branch pipe 11 are closed. Multiple evenly distributed liquid outlet holes 12 are opened on the U-shaped branch pipe 11. The main liquid inlet pipe 9 is connected to the liquid outlet end of the circulation component. In this way, the liquid is sprayed in all directions through the liquid outlet holes 12, which accelerates the flow of chemical liquid in the chemical tank 1.

[0024] In this embodiment, the U-shaped branch pipe 11 is inclined.

[0025] In this embodiment, one end of the outlet pipe assembly 13 is connected to the inlet end of the circulation component, and the other end is inserted into the upper end of the chemical tank 1.

[0026] In this embodiment, an L-shaped overflow baffle 14 is also provided on the outer side of the upper end of the chemical tank 1. The inner side of the L-shaped overflow baffle 14 forms an overflow groove with the outer wall of the chemical tank 1. An overflow port is provided at the bottom of the overflow groove. The overflow port is connected to an overflow pipe 15. The overflow pipe 15 is connected to a circulation component. In this way, the overflowing chemical liquid can be discharged and recycled.

[0027] In this embodiment, a serrated overflow notch is provided at the upper end of the chemical tank 1.

[0028] In this embodiment, the vacuuming device includes a vacuuming pipeline 16 and a vacuum pump. The vacuum pump is located outside the isolation component. One end of the vacuuming pipeline 16 is connected to the middle of the isolation component, and the other end is connected to the suction port of the vacuum pump. In this way, the structure is simple and effective, and can ensure the negative pressure effect.

[0029] In this embodiment, the wafer placement rack 8 includes two baffles 17 on the left and right and a baffle bar 18 disposed between the two baffles 17. There are four baffle bars 18 arranged in a V-shape. The space between each baffle bar 18 is for the flow of chemical liquid. Each baffle bar 18 has several limiting grooves 19 for inserting wafers. The width of the baffle 17 is the same as the width of the flow channel 10. The wafer placement rack 8 is located directly above the flow channel 10. The lower end of the baffle 17 is fixed to the partition plate 7. The chemical liquid flowing upward in the flow channel 10 can move towards the wafer, so that the wafer can fully contact and react with the chemical liquid, thereby ensuring the reaction effect. At the same time, due to the flow of the chemical liquid, it can carry away the air bubbles adsorbed on the wafer, improving the yield.

[0030] Finally, it should be noted that the above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art can still modify the technical solutions described in the foregoing embodiments or make equivalent substitutions for some of the technical features. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A sealed vacuum chemical bath according to claim 1, characterized in that: The isolation component includes a rectangular outer shell and an end cap covering the top of the outer shell. The outer shell has mounting holes for the chemical liquid circulation pipe and the vacuum device pipeline to pass through.

2. The sealed vacuum chemical bath according to claim 2, characterized in that: The end cap and the outer shell have a sealing structure. The sealing structure includes a concave or convex structure disposed on the top side of the outer shell and a convex or concave structure disposed on the inner side of the end cap. The diameter of the end cap is larger than the diameter of the outer shell. A sealing strip is disposed in the recessed part of the concave structure. When the end cap and the outer shell are fastened together, the sealing strip can abut against the convex structure.

3. The sealed vacuum chemical bath according to claim 1, characterized in that: The chemical tank is a rectangular structure with an opening at the top. A partition is provided in the middle of the chemical tank, and a wafer placement rack is provided on the partition. A flow channel is opened on the partition. The chemical liquid circulation pipe includes an inlet pipe group located below the partition and an outlet pipe group located at the top of the chemical tank.

4. A sealed vacuum chemical bath according to claim 4, characterized in that: It also includes a circulation component, in which the inlet pipe assembly, chemical tank, and outlet pipe assembly form a circulation of the chemical liquid under the action of the circulation component.

5. A sealed vacuum chemical bath according to claim 5, characterized in that: The liquid inlet pipe assembly includes a main liquid inlet pipe and a U-shaped branch pipe. The middle of the U-shaped branch pipe is connected to the main liquid inlet pipe, and both ends of the U-shaped branch pipe are closed. Multiple evenly distributed liquid outlet holes are opened on the U-shaped branch pipe. The main liquid inlet pipe is connected to the liquid outlet end of the circulation component.

6. A sealed vacuum chemical bath according to claim 5, characterized in that: One end of the outlet pipe assembly is connected to the inlet end of the circulation component, and the other end is inserted into the upper end of the chemical tank.

7. A sealed vacuum chemical bath according to claim 5, characterized in that: An L-shaped overflow baffle is also provided on the upper outer side of the chemical tank. The inner side of the L-shaped overflow baffle and the outer wall of the chemical tank form an overflow groove. An overflow port is provided at the bottom of the overflow groove. The overflow port is connected to an overflow pipe, which is connected to the circulation component.

8. A sealed vacuum chemical bath according to claim 1, characterized in that: The vacuuming device includes a vacuuming pipeline and a vacuum pump. The vacuum pump is located outside the isolation component. One end of the vacuuming pipeline is connected to the middle of the isolation component, and the other end is connected to the suction port of the vacuum pump.

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