Wafer edge cleaning and etching method

Abstract

The present invention provides a wafer edge cleaning and etching method, comprising: step S1, obtaining a wafer and placing the wafer on a placement table; step S2, controlling the placement table to rotate and controlling multiple spray pipes to sequentially spray solutions to perform multi-layer edge cleaning and etching on the edge of the wafer. The beneficial effect is that the method uses multiple spray pipes to sequentially spray a first solution, a second solution, and a third solution to perform edge cleaning and etching on the edge of the wafer, completely removing surface material from the wafer edge and effectively improving the cleaning and etching effect.

Description

Technical Field

[0001] The present invention relates to the technical field of wafer edge cleaning and etching, and in particular to a wafer edge cleaning and etching method. Background Art

[0002] Before the wafer is prepared, it needs to be cleaned. Water or a general cleaning solution is usually used to quickly clean the surface of the wafer. After cleaning, the surface of the wafer is immediately etched.

[0003] However, this cleaning method cannot completely remove the surface material at the edge of the wafer, which will affect the subsequent wafer etching and cannot effectively protect the wafer. Summary of the Invention

[0004] In view of the problems existing in the prior art, the present invention provides a wafer edge cleaning and etching method, which specifically includes the following steps:

[0005] Step S1, obtaining a wafer and placing the wafer on a placement table;

[0006] Step S2, controlling the placement table to rotate, and controlling a plurality of spray pipes to spray solution in sequence to perform edge cleaning and etching on the edge of the wafer.

[0007] Preferably, in step S2, edge cleaning and etching are performed on the edge of the wafer by a side cleaning and etching device, and the side cleaning and etching device comprises:

[0008] a first spray pipe, for spraying a first solution onto the edge of the wafer to remove surface substances;

[0009] a second spray pipe, configured to spray a second solution onto the edge of the wafer to remove the remaining first solution;

[0010] a third spray pipe, configured to spray a third solution onto the edge of the wafer to etch the edge of the wafer;

[0011] A fourth spray pipe is used to spray a fourth solution to the edge of the wafer to remove the remaining third solution.

[0012] Preferably, the step S2 includes:

[0013] Step S21, controlling the placement table to rotate, and controlling the first spray pipe to spray the first solution onto the surface of the wafer for edge cleaning;

[0014] Step S22, when the first spray pipe finishes spraying, controlling the second spray pipe to spray the second solution to the edge of the wafer to remove the remaining first solution;

[0015] Step S23, when the second spray pipe finishes spraying, controlling the third spray pipe to spray the third solution to the edge of the wafer for etching;

[0016] Step S24 , when the spraying of the third spray pipe is finished, controlling the fourth spray pipe to spray the fourth solution to the edge of the wafer to remove the remaining third solution.

[0017] Preferably, the first spray pipe, the second spray pipe, the third spray pipe and the fourth spray pipe are respectively provided with a first delivery pipe, and the step S2 includes:

[0018] The first delivery pipes are controlled to be conductive so as to deliver the first solution, the second solution, the third solution and the fourth solution to the first spray pipe, the second spray pipe, the third spray pipe and the fourth spray pipe respectively in an external liquid supply device.

[0019] Preferably, the first spray pipe, the second spray pipe, the third spray pipe and the fourth spray pipe are respectively provided with a second delivery pipe, and after executing step S24, the following further steps are included:

[0020] Step S35 , controlling each of the second delivery pipes to be conductive to respectively deliver the first solution, the second solution, the third solution, and the fourth solution remaining in the first spray pipe, the second spray pipe, the third spray pipe, and the fourth spray pipe to an external recovery device for recovery.

[0021] Preferably, the first solution consists of phosphoric acid and deionized water.

[0022] Preferably, the second solution and the fourth solution are ultrapure water.

[0023] Preferably, the third solution is high-temperature sulfuric acid.

[0024] The above technical solution has the following advantages or beneficial effects: This method uses multiple spray pipes to spray the first solution, the second solution and the third solution in sequence to perform edge cleaning and etching on the edge of the wafer, so as to completely remove the surface material on the edge of the wafer and effectively improve the etching effect. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 A flowchart of the steps of the method in a preferred embodiment of the present invention is shown below;

[0026] Figure 2 This is a specific flow chart of step S2 in a preferred embodiment of the present invention. DETAILED DESCRIPTION

[0027] The present invention is described in detail below with reference to the accompanying drawings and specific embodiments. The present invention is not limited to this embodiment, and other embodiments may also fall within the scope of the present invention as long as they conform to the gist of the present invention.

[0028] In a preferred embodiment of the present invention, based on the above problems existing in the prior art, a wafer edge cleaning and etching method is provided. Figure 1 As shown, the specific steps include:

[0029] Step S1, obtaining a wafer and placing the wafer on a placement table;

[0030] Step S2: Control the placement table to rotate, and control the multiple spray pipes to spray the solution in sequence to perform edge cleaning and etching on the edge of the wafer.

[0031] Specifically, in this embodiment, in actual operation, it is necessary to use a pure air blowing unit to blow hot air to the surface of the wafer to increase the airflow speed, form a normal temperature at the center of the bottom of the wafer, increase the temperature at the edge of the wafer, concentrate the flow and processing of the solution at the edge of the wafer, and use a stepped strong convection method to flow.

[0032] Specifically, in this embodiment, the surface of the wafer can be oxidized in an oxidation furnace. The temperature of the oxidation furnace is set to 600-900°C and the time is set to 30 minutes. The temperature and time of the oxidation treatment can be adaptively modified according to specific circumstances.

[0033] Specifically, in this embodiment, the spray pipe can adopt a multi-cavity structure design. Corresponding to the configuration and use of various spray pipes, four cavities with phase shift for vertical lifting can be set. The cavities spaced apart in pairs form a combination, and a combined cavity is matched with a vertical lifting mechanism device symmetrical on both sides for phase arrangement and distribution.

[0034] Preferably, cavity No. 1 and cavity No. 3 can be set as a group, corresponding to vertical moving devices No. 1 and No. 2, and cavity No. 2 and cavity No. 4 can be set as a group, corresponding to vertical moving devices No. 3 and No. 4.

[0035] Preferably, since the solution is concentrated at the edge of the wafer, in the design of the cavity, there are corresponding reduced space and discharge positions when guiding the flow, so that the overall cavity position can be effectively utilized.

[0036] Preferably, since the solutions react with each other and form a step-by-step adjusted flow field with cold flow and hot flow, there are corresponding separate hot flow discharge channels and cold flow discharge channels to effectively increase the discharge efficiency.

[0037] In a preferred embodiment of the present invention, in step S2, edge cleaning and etching is performed on the edge of the wafer by a side cleaning and etching device, and the side cleaning and etching device includes:

[0038] a first spray pipe, for spraying a first solution onto the edge of the wafer to remove surface substances;

[0039] a second spray pipe, for spraying a second solution to the edge of the wafer to remove the remaining first solution;

[0040] a third spray pipe, for spraying a third solution onto the edge of the wafer to etch the edge of the wafer;

[0041] A fourth spray pipe is used to spray a fourth solution to the edge of the wafer to remove the remaining third solution.

[0042] Specifically, in this embodiment, considering that the spray angle under normal circumstances is to spray directly from above and move in an arc diffusion below, but in this embodiment, the first spray pipe, the second spray pipe, the third spray pipe, the fourth spray pipe and the fifth spray pipe only need to spray the edge of the wafer, so the spray angle of the first spray pipe, the second spray pipe, the third spray pipe, the fourth spray pipe and the fifth spray pipe is set to a bending angle of 60-80 degrees from the phase angle of the normal line of the center of the wafer, so that the spraying process can achieve the corresponding spraying on the edge of the wafer.

[0043] Preferably, the length of the pipes connecting the first spray pipe, the second spray pipe, the third spray pipe, the fourth spray pipe and the fifth spray pipe needs to be adjusted to 10% of the distance from the central axis of the wafer.

[0044] Preferably, the swing amplitude of the pipe needs to be adjusted to move only to two positions:

[0045] For the swing amplitude of the liquid collecting position, return the pipe swing amplitude to the starting position to collect the liquid, and adjust the swing amplitude to the spacing position between the pipe cavity and the wafer;

[0046] As for the swing of the spray position, the tube is slightly swung between the cavity and the edge of the wafer, and the rotation of the wafer can be adjusted to spray only the edge of the wafer.

[0047] Specifically, in this embodiment, each spray pipe corresponds to three spray modes due to different chemical solutions:

[0048] The first is a spot-release spraying method, which uses short-frequency sound waves to intercept microfluids and integrates the control of the instantaneous output of chemical liquids to produce a spot-release output model.

[0049] The second type is direct spray, which performs general spraying action and is equipped with the integrated output of instantaneous output chemical liquid to produce a direct spray output model.

[0050] The third type is nano-atomization spray, which corresponds to the special nano-level atomization effect to maintain the ability to control droplets. It has the following key features: nitrogen jet is implanted into the liquid, high-frequency sound wave oscillation liquid atomization, and the nozzle angle is opened and closed to produce a nano-atomization output model.

[0051] Specifically, in this embodiment, since the solution sprayed by each spray pipe in this method is mainly concentrated at the edge of the wafer, the particle control and flow field distribution during the edge washing and etching process of the wafer need to enhance the stage-by-stage control of the flow field in the center and outer edge areas of the wafer.

[0052] In a preferred embodiment of the present invention, Figure 2 As shown, step S2 includes:

[0053] Step S21, controlling the placement table to rotate, and controlling the first spray pipe to spray the first solution onto the surface of the wafer to wash the edge;

[0054] Step S22, when the first spray pipe finishes spraying, controlling the second spray pipe to spray the second solution to the edge of the wafer to remove the remaining first solution;

[0055] Step S23, when the second spray pipe finishes spraying, controlling the third spray pipe to spray the third solution to the edge of the wafer for etching;

[0056] Step S24 , when the spraying of the third spray pipe is finished, the fourth spray pipe is controlled to spray the fourth solution to the edge of the wafer to remove the remaining third solution.

[0057] In a preferred embodiment of the present invention, a first delivery pipe is provided on each of the first spray pipe, the second spray pipe, the third spray pipe, and the fourth spray pipe, and step S2 includes:

[0058] The first delivery pipes are controlled to be conductive so as to deliver the first solution, the second solution, the third solution and the fourth solution to the first spray pipe, the second spray pipe, the third spray pipe and the fourth spray pipe respectively in an external liquid supply device.

[0059] In a preferred embodiment of the present invention, a second delivery pipe is provided on each of the first spray pipe, the second spray pipe, the third spray pipe, and the fourth spray pipe, and after executing step S24, the following steps are further included:

[0060] In step S35 , the second delivery pipes are controlled to be conductive to deliver the remaining first solution, second solution, third solution and fourth solution in the first spray pipe, the second spray pipe, the third spray pipe and the fourth spray pipe to an external recovery device for recovery.

[0061] In a preferred embodiment of the present invention, the first solution consists of phosphoric acid and deionized water.

[0062] In a preferred embodiment of the present invention, the second solution and the fourth solution are ultrapure water.

[0063] In a preferred embodiment of the present invention, the third solution is high-temperature sulfuric acid.

[0064] Example 1:

[0065] The wafer is a gallium nitride-based device. A protective layer is deposited on the surface of the gallium nitride-based device, photoresist is coated on the protective layer, and a photolithographic etching pattern is performed. The protective layer in the area to be etched is then etched and the remaining photoresist is removed. The gallium nitride-based device is oxidized under high temperature conditions and then placed in a chemical solution for etching.

[0066] Preferably, the gallium nitride-based device is a semiconductor device based on the material properties of gallium nitride, such as a heterojunction device and an LED device.

[0067] Preferably, the protective layer may be made of materials such as silicon dioxide or silicon nitride.

[0068] Preferably, the etching method includes but is not limited to reactive ion etching and solution immersion.

[0069] Preferably, the deposition method includes but is not limited to plasma enhanced vapor deposition, low pressure chemical vapor deposition, and optical thin film deposition, with plasma enhanced vapor deposition being preferred.

[0070] Example 2:

[0071] A silicon dioxide protective layer is deposited on the wafer surface, and the oxide is etched and removed using hydrofluoric acid such as DHF (Dilute HydroFluoric acid), BOE (Buffered Oxide Etch), and HF (Hydrofluoric Acid) as the main agent to ensure that the residual silicon oxide is removed. Then, high-temperature phosphoric acid such as HPO (H3PO4 orthophosphoric acid) is used as the main agent to etch and remove the nitride layer to ensure that the residual silicon nitride and pattern selective etching are removed, and the silicon nitride layer pattern is corrected. Then, high-temperature sulfuric acid such as SPM (Surfuric / Peroxide Mi sulfuric acid and hydrogen peroxide mixed solution) is used as the main agent to strip and remove organic matter such as photoresist and photoacid. After the pattern is formed, reverse photoresist removal is performed to ensure that the cleaning is complete.

[0072] Preferably, the phosphoric acid used needs to be heated in a phosphoric acid tank first. The shorter the time required to heat from room temperature (20° C.) to the target temperature (160° C.), the better. The heating at this stage is 100% full output.

[0073] Preferably, when treating the phosphoric acid aqueous solution in the phosphoric acid tank, the boiling state of the phosphoric acid aqueous solution can be adjusted by adjusting the heating set value X of the phosphoric acid tank. If the temperature is within ±2°C of the target temperature, the output is X%. If the temperature exceeds the target temperature by 2°C, the output is 0.5X%. At the same time, the heating set value X is automatically decreased by 1%. If the temperature is 2°C below the target temperature, the output is 100%. If the temperature enters the set temperature control range and then falls out of the temperature control range, the output is divided by 100%, and X is automatically increased by 1%.

[0074] The above description is only a preferred embodiment of the present invention and does not limit the implementation mode and protection scope of the present invention. For those skilled in the art, it should be aware that all solutions obtained by equivalent substitutions and obvious changes made using the content of this specification and illustrations should be included in the protection scope of the present invention.

Claims

1. A wafer edge cleaning and etching method, characterized in that: Specifically include the following steps: Step S1, obtaining a wafer and placing the wafer on a placement table; Step S2, controlling the placement table to rotate, and controlling the plurality of spray pipes to sequentially spray solution to perform edge cleaning and etching on the edges of the wafer; In step S2, a pure air blowing unit is used to blow hot air onto the surface of the wafer to increase the airflow speed, forming a normal temperature at the center of the bottom of the wafer and increasing the temperature at the edge of the wafer, concentrating the flow and processing of the solution at the edge of the wafer, and adopting a stepped strong convection method; The spray pipe is provided with multiple cavities that move in phase and are vertically lifted. The cavities spaced in pairs form a combination. The cavities in a combination are matched with vertical lifting devices that are symmetrical on both sides to be arranged and distributed in phase.

2. The wafer edge cleaning and etching method according to claim 1, wherein: In step S2, edge cleaning and etching are performed on the edge of the wafer by a side cleaning and etching device, and the side cleaning and etching device includes: a first spray pipe, for spraying a first solution onto the edge of the wafer to remove surface substances; a second spray pipe, configured to spray a second solution onto the edge of the wafer to remove the remaining first solution; a third spray pipe, configured to spray a third solution onto the edge of the wafer to etch the edge of the wafer; A fourth spray pipe is used to spray a fourth solution to the edge of the wafer to remove the remaining third solution.

3. The wafer edge cleaning and etching method according to claim 2, wherein: The step S2 comprises: Step S21, controlling the placement table to rotate, and controlling the first spray pipe to spray the first solution onto the surface of the wafer for edge cleaning; Step S22, when the first spray pipe finishes spraying, controlling the second spray pipe to spray the second solution to the edge of the wafer to remove the remaining first solution; Step S23, when the second spray pipe finishes spraying, controlling the third spray pipe to spray the third solution to the edge of the wafer for etching; Step S24 , when the spraying of the third spray pipe is finished, controlling the fourth spray pipe to spray the fourth solution to the edge of the wafer to remove the remaining third solution.

4. The wafer edge cleaning and etching method according to claim 2, wherein: The first spray pipe, the second spray pipe, the third spray pipe, and the fourth spray pipe are respectively provided with a first delivery pipe, and step S2 includes: The first delivery pipes are controlled to be conductive so as to deliver the first solution, the second solution, the third solution and the fourth solution to the first spray pipe, the second spray pipe, the third spray pipe and the fourth spray pipe respectively in an external liquid supply device.

5. The wafer edge cleaning and etching method according to claim 3, wherein: The first spray pipe, the second spray pipe, the third spray pipe, and the fourth spray pipe are respectively provided with a second delivery pipe, and after executing step S24, the following further comprises: Step S35 , controlling each of the second delivery pipes to be conductive to respectively deliver the first solution, the second solution, the third solution, and the fourth solution remaining in the first spray pipe, the second spray pipe, the third spray pipe, and the fourth spray pipe to an external recovery device for recovery.

6. The wafer edge cleaning and etching method according to claim 2, wherein: The first solution consists of phosphoric acid and deionized water.

7. The wafer edge cleaning and etching method according to claim 2, wherein: The second solution and the fourth solution are ultrapure water.

8. The wafer edge cleaning and etching method according to claim 2, wherein: The third solution is high-temperature sulfuric acid.

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