Wet etching equipment
By using atomizing nozzles and vertically arranged wafer clamps in wet etching equipment, combined with nitrogen sealing and pressure control, the problems of lateral lateral etching and uneven temperature in high-precision applications are solved, and a more uniform and accurate etching effect is achieved.
Patent Information
- Application Number
- CN202421478394.7
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2024-06-26
- Publication Date
- 2025-04-11
- Estimated Expiration
- 2034-06-26
AI Technical Summary
Existing wet etching equipment is subject to greater limitations in high-precision applications, and uneven wafer surface temperature leads to poor product uniformity and serious overetching problems.
A wet etching device is designed, using atomizing nozzles and vertically arranged wafer clamps. Through nitrogen sealing and pressure control, the etching liquid prevents the wafer's reverse structure from destroying the wafer's reverse structure, and the vertical placement and rotation design of the wafer is designed to achieve more uniform etching.
It improves the uniformity and accuracy of etching, prevents the etching liquid from destroying the wafer reverse structure, reduces over-etching, and improves the product yield.
Smart Images
Figure CN222749451U_ABST
Abstract
Description
Technical Field
[0001] The utility model relates to the field of wet etching, in particular to a wet etching device. Background Art
[0002] Etching process is an indispensable part of semiconductor manufacturing technology. Common etching methods include dry etching and wet chemical etching. Dry etching includes reactive ion etching, ion beam etching, plasma etching, etc. Dry etching has extremely small lateral etch and high graphic accuracy, but the process is complex, the etching rate is low, and the equipment is expensive. Wet etching has low cost and fast etching rate, and is often chosen by most manufacturers. However, its lateral etch is relatively large, which limits the application of wet process in high-precision occasions.
[0003] At present, wet etching equipment is divided into tank wet etching equipment and single-wafer wet etching equipment. Tank wet etching is to immerse one or more wafers in a well-proportioned etching solution tank for chemical etching. Wet etching is isotropic etching, and the ideal etching depth-to-width ratio under ideal conditions is 1:1. Due to changes in the concentration of the etching solution and the appearance of residues on the sample surface during the etching process, the etching time cannot be accurately controlled, and the product yield is not high. In addition, the surface temperature of the wafer has a great influence on the etching rate. The etching reaction process is an exothermic process. If the surface temperature of the wafer is uneven, it will directly lead to poor uniformity of the final product.
[0004] Single-wafer wet etching equipment refers to wet etching equipment that only operates on one wafer per process. Existing equipment generally places the wafer to be etched on a rotating horizontal base, and a nozzle is set above the center of the wafer surface, through which the etching liquid is sprayed onto the wafer. The wafer rotates at a certain speed so that the etching liquid can evenly cover the entire wafer surface for chemical etching. Compared with the tank-type wet etching equipment, the etching liquid in contact with the wafer surface is uniform and flowing. On the one hand, the residue and heat generated by the etching reaction will be taken away in time. On the other hand, the solution flows, and its concentration is basically constant, which can ensure a good etching rate and good uniformity.
[0005] The single-wafer wet etching equipment sprays the etching liquid on the center area of the wafer. When the wafer rotates, the etching liquid is affected by the centrifugal force and moves away from the center of the circle, and the flow speed gradually increases, so that the etching liquid has the same temperature and flow rate at the same distance from the geometric center of the wafer. Therefore, the etching rates at the same distance from the geometric center of the wafer are relatively similar, that is, the etching rates at the concentric circles of the wafer are relatively similar. Therefore, the center area of the wafer is prone to fast etching rate and over-etching.
[0006] In addition, in some single-sided etching processes, etching solution sputtering will damage the non-etched surface of the wafer, thereby affecting the requirements of the etching process. Utility Model Content
[0007] The utility model discloses a wet etching device, which is used to solve relevant technical problems in the background technology.
[0008] The technical solution provided by the utility model is as follows: a wet etching device, comprising: an etching chamber, a fixture base for clamping a wafer in the etching chamber so that the wafer is arranged vertically, an atomizing nozzle parallel to the wafer, a solution tank connected to the atomizing nozzle, and a motor on the other side of the fixture to drive the fixture base to rotate;
[0009] Among them, the clamp base includes: a base body, a clamp body connected to the base body, and a pressure ring connected to the clamp body and used to clamp and fix the wafer; the clamp body has a circular clamping boss opened inwardly, the wafer is clamped and fixed in the clamping boss, and the clamping boss and the wafer bonding surface are sealed by a fluororubber ring; a nitrogen port is passed through the center of the base and the clamp, and nitrogen is supplied to the non-etching surface of the wafer in the clamping boss.
[0010] In one embodiment, the atomizing nozzle is movably connected to the etching chamber, and the distance between the atomizing nozzle and the wafer is adjustable.
[0011] In one embodiment, the surface area of the atomizing nozzle is larger than the surface area of the wafer.
[0012] In one embodiment, the solution tank is connected to the atomizing nozzle through a first pipeline and a second pipeline in parallel. A pressure regulating valve is provided on the parallel pipeline of the first pipeline and the second pipeline. The first pipeline has a booster pump flowing toward the atomizing nozzle, and the second pipeline has a pressure-controlling one-way valve flowing toward the solution tank.
[0013] In one embodiment, the solution tank is set to be a constant temperature, and a heating rod, a water cooling device and a thermometer are used in the solution tank for constant temperature control.
[0014] In one embodiment, a stirring device is provided in the solution tank.
[0015] In one embodiment, flow meters are respectively provided on the DI water pipeline and the HF solution pipeline for supplying liquid into the solution tank.
[0016] In one embodiment, there is a recovery pipeline between the solution tank and the etching chamber, and the recovery pipeline includes: a third pipeline and a fourth pipeline, the third pipeline is connected to the etching chamber and the solution tank, and the third pipeline has a recovery valve; the fourth pipeline is connected to the etching chamber and is used for discharging waste liquid, and the fourth pipeline has a drain valve and a PH detection device.
[0017] In one embodiment, the atomizing nozzle is also separately connected to a nitrogen source and a DI water source.
[0018] In one embodiment, a pressure controller for adjusting the pressure is connected to the passage for introducing nitrogen from the nitrogen port.
[0019] Compared with the prior art, the beneficial effects of the utility model are:
[0020] (1) The wet etching equipment of the utility model fixes the wafer on the fixture body by means of a pressure ring, and the non-etching surface of the wafer and the fixture body are sealed by a fluororubber ring to form a sealed space, with nitrogen passing through the center. Through pressure control, a constant positive pressure is ensured in the sealed space, thereby preventing the etching solution from damaging the back surface structure of the wafer.
[0021] (2) The wet etching equipment of the utility model is designed with a vertically placed and rotating wafer. When the mist droplets vertically hit the surface of the wafer and react, they will flow downward under the influence of gravity. When rotating, the etching liquid will flow, thereby achieving more uniform etching. BRIEF DESCRIPTION OF THE DRAWINGS
[0022] Figure 1 It is a schematic diagram of the overall structure of the wet etching equipment of the utility model;
[0023] Figure 2 It is a schematic diagram of the piping structure of the etching chamber and the solution tank in the utility model;
[0024] Figure 3 It is a structural schematic diagram of the clamp base in the utility model.
[0025] The accompanying drawings are marked as follows: 1. Etching chamber; 2. Clamp base; 201. Base body; 202. Clamp body; 203. Pressing ring; 204. Clamping boss; 205. Fluorine rubber ring; 206. Nitrogen port; 3. Wafer; 4. Atomizing nozzle; 5. Solution tank; 6. Motor; 7. First pipeline; 8. Second pipeline; 9. Parallel pipeline; 10. Pressure regulating valve; 11. Booster pump; 12. Pressure control check valve; 13. Heating rod; 14. Water cooling device; 15. Thermometer; 16. Stirring device; 17. DI water pipeline; 18. HF solution pipeline; 19. Flow meter; 20. Third pipeline; 21. Fourth pipeline; 22. Recovery valve; 23. Drain valve; 24. PH detection device; 25. Nitrogen source; 26. DI water source; 27. Pressure controller. DETAILED DESCRIPTION
[0026] The present invention is described in detail below in conjunction with specific embodiments. The following embodiments will help those skilled in the art to further understand the present invention, but are not intended to limit the present invention in any form. It should be noted that, for those of ordinary skill in the art, several changes and improvements can also be made without departing from the concept of the present invention. These all belong to the protection scope of the present invention.
[0027] like Figure 1-3 As shown, the utility model is a wet etching device, comprising: an etching chamber 1, a fixture base 2, an atomizing nozzle 4, a solution tank 5, and a motor 6; a wafer 3 is clamped in the fixture base 2, and the wafer 3 is arranged vertically, the atomizing nozzle 4 is in the etching chamber 1 and parallel to the wafer 3, the motor 6 is connected to the outside of the etching chamber 1, and its output shaft end passes through the etching chamber 1 and is connected to the fixture base 2, driving the fixture base 2 to rotate; wherein the fixture base 2 comprises: a base body 201, a fixture body 202 connected to the base body 201, and a pressure ring 203 connected to the fixture body 202 and used to clamp and fix the wafer 3; the fixture body 202 is provided with a circular clamping boss 204 inwardly, the The wafer 3 is clamped and fixed in the clamping boss 204, and the clamping boss 204 and the bonding surface of the wafer 3 are sealed by a fluororubber ring 205; a nitrogen port 206 is passed through the base and the center of the clamp, and nitrogen is supplied to the non-etched surface of the wafer 3 in the clamping boss 204; when working, the motor 6 drives the clamp base 2 to rotate, and the atomizing nozzle 4 sprays etching liquid to the wafer 3. At the same time, the nitrogen port 206 supplies nitrogen to the non-etched surface of the wafer 3; the non-etched surface of the wafer 3 and the clamp body 202 are sealed by the fluororubber ring 205 to form a sealed space, and nitrogen is passed through the center. After pressure control, a constant positive pressure is guaranteed in the sealed space, thereby preventing the etching liquid from damaging the reverse structure of the wafer 3.
[0028] In this embodiment, a pressure controller 27 for adjusting the pressure is connected to the passage for nitrogen gas to enter the nitrogen port 206 .
[0029] In this embodiment, by the design of vertical placement and rotation of the wafer 3, when the mist droplets vertically hit the surface of the wafer 3 and react, they will flow downward under the influence of gravity, and when rotating, the etching liquid will flow, thereby achieving more uniform etching. Specifically, the fixture base 2 rotates with the wafer 3, which improves the etching uniformity and can also throw out the reaction residues in time and take away the heat generated by the reaction.
[0030] In this embodiment, the atomizing nozzle 4 is movably connected in the etching chamber 1, and the distance between the atomizing nozzle 4 and the wafer 3 is adjustable; specifically, the atomizing nozzle 4 can be driven to move squarely relative to the wafer 3 by a screw module or a telescopic cylinder mechanism to achieve the adjustment action.
[0031] In this embodiment, the surface area of the atomizing nozzle 4 is larger than the surface area of the wafer 3 , so that the atomized etching liquid can be sprayed on the entire etching surface of the wafer 3 , further improving the uniformity of etching.
[0032] In this embodiment, the solution tank 5 is connected to the atomizing nozzle 4 through a first pipeline 7 and a second pipeline 8 in parallel. A pressure regulating valve 10 is provided on the parallel pipeline 9 of the first pipeline 7 and the second pipeline 8. The first pipeline 7 is provided with a booster pump 11 flowing toward the atomizing nozzle 4, and the second pipeline 8 is provided with a pressure-controlling one-way valve 12 flowing toward the solution tank 5. Specifically, the booster pump 11 extracts the etching solution in the solution tank 5 for pressurization treatment. The booster pump 11 is connected in parallel with a 0.5MPa pressure-controlling one-way valve 12 to ensure that the pressure on the first pipeline 7 and the parallel pipeline 9 of the booster pump 11 is constant at 0.5MPa. If the pressure exceeds 0.5MPa, the pressure-controlling one-way valve 12 is opened to release the pressure, and the etching solution will return to the solution tank 5 through the second pipeline 8 and the pressure-controlling one-way valve 12. The pressure of the atomizing nozzle 4 is adjusted by the pressure regulating valve 10, and the range is 0-0.5MPa.
[0033] The atomizing nozzle 4 of this embodiment can cover the entire surface of the wafer 3, and the etching liquid pressure and the distance from the wafer 3 are adjustable, so as to further accurately control the etching rate and aspect ratio, so that the entire surface of the wafer 3 can be etched more evenly.
[0034] The solution tank 5 is set to be constant temperature, and the solution tank 5 is used for constant temperature control through a heating rod 13, a water cooling device 14 and a thermometer 15; the solution tank 5 is provided with a stirring device 16; and flow meters 19 are respectively provided on the DI water pipeline 17 and the HF solution pipeline 18 that supply liquid to the solution tank 5. Specifically: the solution tank 5 controls the ratio of DI water and HF solution respectively through the flow meter 19. After the ratio is completed, the solution is stirred by the stirring device 16 to make the solution more uniform; then the temperature is controlled by the heating rod 13 and the water cooling device 14, and the temperature is measured in real time by the thermometer 15 to achieve constant temperature control. Through the constant temperature control of the solution tank 5, the etching solution is kept at a constant temperature, and the temperature sprayed to each area of the wafer 3 is uniform and stable, which further improves the uniformity of etching.
[0035] In this embodiment, DI water is deionized water, and HF solution is hydrofluoric acid solution.
[0036] The positions of the heating rod 13, stirring device 16, water cooling device 14 and thermometer 15 of this embodiment are reasonably arranged according to actual usage, and the heating rod 13, stirring device 16, water cooling device 14 and thermometer 15 are all existing mature products and will not be repeated in this solution.
[0037] In this embodiment, flow meters 19 are respectively provided on the DI water pipeline 17 and the HF solution pipeline 18 to control the DI water and the HF solution, so as to achieve the purpose of solution ratio, thereby achieving a better etching effect.
[0038] In this embodiment, there is a recovery pipeline between the solution tank 5 and the etching chamber 1, and the recovery pipeline includes: a third pipeline 20 and a fourth pipeline 21. The third pipeline 20 is connected with the etching chamber 1 and the solution tank 5, and the third pipeline 20 is provided with a recovery valve 22; the fourth pipeline 21 is connected with the etching chamber 1 and is used for discharging waste liquid, and the fourth pipeline 21 is provided with a drain valve 23 and a pH detection device 24. The etched solution in the etching chamber 1 can open the recovery valve 22 and flow back to the solution tank 5 through the third pipeline 20; the washing water can close the recovery valve 22, open the drain valve 23, and be discharged through the fourth pipeline 21. After the pH value reaches the set value, the washing step is completed. The utilization rate of the solution is improved, and the cleanliness of the washing is ensured at the same time.
[0039] In this embodiment, the atomizing nozzle 4 is also independently connected to the nitrogen source 25 and the DI water source 26, and is independently controlled for cleaning the wafer 3 after etching and drying after cleaning.
[0040] Working steps:
[0041] 1. After the wafer 3 is placed and fixed, the motor 6 rotates, the air is supplied to the back of the wafer 3 to ensure positive pressure, the atomizing nozzle 4 sets the distance, and then sprays the mist etching solution to the surface of the wafer 3 for wet etching, the recovery valve 22 opens, and the solution returns to the HF solution tank 5.
[0042] 2. After etching, the atomizing nozzle 4 introduces DI water through the DI water source 26 to clean the wafer 3. The distance between the atomizing nozzle 4 and the wafer 3 is set, and the wafer 3 is rotated to perform 360° washing without dead angles. The drain valve 23 is opened to discharge the washing water. The fourth pipeline 21 is installed with a PH detection device 24. After the PH value reaches the set value, the cleaning step is completed.
[0043] 3. After wafer 3 is cleaned, it is blown dry.
[0044] In this application, the terms "upper", "lower", "left", "right", "front", "back", "top", "bottom", "inner", "outer", "middle", "vertical", "horizontal", "lateral", "longitudinal" and the like indicate positions or positional relationships based on the positions or positional relationships shown in the drawings. These terms are mainly used to better describe the utility model and its embodiments, and are not used to limit the indicated devices, elements or components to have a specific orientation, or to be constructed and operated in a specific orientation.
[0045] The above description is only the preferred embodiment of the present application and is not intended to limit the present application. For those skilled in the art, the present application may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present application shall be included in the protection scope of the present application.
Claims
1. A wet etching device, characterized in that: include: An etching chamber (1), a fixture base (2) in the etching chamber (1) for clamping a wafer (3) so that the wafer (3) is arranged vertically, an atomizing nozzle (4) parallel to the wafer (3), a solution tank (5) connected to the atomizing nozzle (4), and a motor (6) on the other side of the fixture for driving the fixture base (2) to rotate; The clamp base (2) comprises: a base body (201), a clamp body (202) connected to the base body (201), and a pressure ring (203) connected to the clamp body (202) and used to clamp and fix the wafer (3); the clamp body (202) is provided with a circular clamping boss (204) inwardly, the wafer (3) is clamped and fixed in the clamping boss (204), and the clamping boss (204) and the wafer (3) bonding surface are sealed by a fluororubber ring (205); a nitrogen port (206) is passed through the center of the base body (201) and the clamp body (202), and nitrogen is introduced into the clamping boss (204) and toward the non-etched surface of the wafer (3).
2. A wet etching device as claimed in claim 1, characterized in that: The atomizing nozzle (4) is movably connected to the etching chamber (1), and the distance between the atomizing nozzle (4) and the wafer (3) is adjustable.
3. A wet etching device as claimed in claim 1, characterized in that: The surface area of the atomizing nozzle (4) is greater than the surface area of the wafer (3).
4. A wet etching device as claimed in claim 1, characterized in that: The solution tank (5) is connected to the atomizing nozzle (4) via a first pipeline (7) and a second pipeline (8) connected in parallel; a pressure regulating valve (10) is provided on a pipeline (9) connecting the first pipeline (7) and the second pipeline (8); a booster pump (11) is provided on the first pipeline (7) for flowing toward the atomizing nozzle (4); and a pressure-controlling one-way valve (12) is provided on the second pipeline (8) for flowing toward the solution tank (5).
5. A wet etching device as claimed in claim 1, characterized in that: The solution tank (5) is set to be a constant temperature, and a heating rod (13), a water cooling device (14) and a thermometer (15) are provided in the solution tank (5) for constant temperature control.
6. A wet etching device as claimed in claim 1, characterized in that: The solution tank (5) is provided with a stirring device (16).
7. A wet etching device as claimed in claim 1, characterized in that: A flow meter (19) is provided on the DI water pipeline (17) and the HF solution pipeline (18) for supplying liquid into the solution tank (5), respectively.
8. A wet etching device as claimed in claim 1, characterized in that: A recovery pipeline is provided between the solution tank (5) and the etching chamber (1), and the recovery pipeline comprises: a third pipeline (20) and a fourth pipeline (21); the third pipeline (20) is connected to the etching chamber (1) and the solution tank (5), and the third pipeline (20) is provided with a recovery valve (22); the fourth pipeline (21) is connected to the etching chamber (1) and is used for discharging waste liquid, and the fourth pipeline (21) is provided with a drain valve (23) and a pH detection device (24).
9. A wet etching device as claimed in claim 1, characterized in that: The atomizing nozzle (4) is also separately connected to a nitrogen source (25) and a DI water source (26).
10. A wet etching device as claimed in claim 1, characterized in that: A pressure controller for adjusting the pressure is connected to the passage for introducing nitrogen gas through the nitrogen port (206).