CN115206824A - Controllable multi-air-inlet-pipeline combined air inlet device and etching method - Google Patents

Abstract

The invention discloses a controllable multi-air inlet pipeline combined air inlet device and an etching method, wherein an air inlet pipeline is arranged above a vacuum chamber and comprises a main air inlet mechanism, a shunting air inlet mechanism and an upper chamber cover; the upper cavity cover covers the vacuum cavity, a plurality of branch air inlets are formed in the upper cavity cover, air is introduced from different positions of the upper cavity, so that the gas concentrations at different positions in the cavity are different, the concentrations of the gas at different positions in the cavity are controlled, the plasma concentrations generated by ionization of the gas in the cavity by a high-frequency electric field when the radio frequency is started are different, the generated plasma reacts with etching layer substances on the surface of the wafer to be etched, or a certain substance is generated between the plasmas to be deposited on the surface of the wafer, the gas concentrations at different positions in the cavity are controlled to be different, the etching or deposition coating speed of each position of the wafer in the cavity is controlled to be different, and the purposes of controlling and adjusting the etching and coating uniformity are achieved.

Description

A kind of controllable multi-intake pipeline combined air intake device and etching method

technical field

The invention relates to the technical field of semiconductor manufacturing, in particular to a controllable multi-air-intake pipeline combined air-intake device and an etching method.

Background technique

Plasma etching is the most common form of dry etching. The principle is that the gas exposed to the electron region forms plasma, and the resulting ionized gas and the gas composed of the release of high-energy electrons form plasma or ions. , when the ionized gas atoms are accelerated by the electric field, they release enough force with the surface repelling force to tightly bond the material or etch the surface. The invention is applied to the field of ICP and PECVD equipment to etch wafers. The existing air intake device usually adopts a branch air inlet to make the gas enter the vacuum chamber. However, the existing air intake method still has the following problems:

1. It is difficult to ensure the uniformity of the wafer during etching with only one branch air inlet.

2. The local intake air concentration cannot be adjusted, which is inconvenient for local etching of the wafer.

SUMMARY OF THE INVENTION

The technical problem to be solved by the present invention is to aim at the deficiencies of the above-mentioned prior art, and to provide a controllable multi-air intake pipeline combined air intake device and an etching method. The air intake device passes through multiple intake pipelines and branch air inlets , so that the gas concentration and the generated plasma concentration are different in different positions of the vacuum chamber, so as to control the different positions of the wafer to etch or deposit the coating film in the chamber, so as to control and adjust the uniformity of the etching and the coating film.

In order to solve the above-mentioned technical problems, the technical scheme adopted in the present invention is:

A controllable multi-air intake pipeline combined air intake device, the air intake device is arranged above a vacuum chamber, and includes a total air intake mechanism, a split air intake mechanism and an upper chamber cover; the upper chamber cover is covered on the vacuum chamber , and the upper chamber cover is provided with a plurality of branch air inlets, and the upper chamber cover is provided with a central air inlet;

The general air intake mechanism includes: a gas cabinet, a first general air intake pipeline, a second general air intake pipeline, an air storage cavity, a central air inlet and an air intake diaphragm valve; one end of the first general air intake pipeline is connected to the gas cabinet, and the second general air intake pipeline One end of the general air intake pipeline is connected to the first general air intake pipeline, and the other end is connected to the air storage chamber, and the air intake diaphragm valve is located on the second general air intake pipeline; the air storage chamber is arranged on the central air inlet;

The split air intake mechanism includes: a first intake pipe, a second intake pipe, and a first main intake pipe; one end of the first intake pipe and the second intake pipe are jointly connected to one end of the first main intake pipe, and the first intake pipe and the first intake pipe are connected to one end of the first main intake pipe. The other end of the second air intake pipe is connected to the edge of the upper cavity cover through the branch air inlet, the other end of the first main air intake pipe is connected to the other end of the first general air intake pipe, and the first air intake pipe and the second air intake pipe are provided with Diaphragm valve.

As a further preference of the present invention, the split air intake mechanism further comprises: a third air intake pipe, a fourth air intake pipe, and a second main air intake pipe. One end, the other ends of the third air intake pipe and the fourth air intake pipe are connected to the edge of the upper chamber cover through the branch air inlet, the other end of the second main air intake pipe is connected to the first general air intake pipe, the third air intake pipe, the fourth air intake pipe There is a diaphragm valve on the intake pipe.

As a further preference of the present invention, the intake diaphragm valve and the intake valve are pneumatic valves.

As a further preference of the present invention, a circular groove is formed on the upper cavity cover, and a window is arranged in the circular groove.

As a further preference of the present invention, it also includes a radio frequency capacitor and a radio frequency coil, the radio frequency coil is a threaded spiral structure, placed in the window, and the radio frequency capacitor is connected to the radio frequency coil.

As a further preference of the present invention, a solenoid valve is also included, the diaphragm valve and the intake diaphragm valve are connected to a solenoid valve, and the solenoid valve is controlled and switched by a PLC; the PLC is connected to the host computer.

As a further preference of the present invention, the first overall intake pipe, the second overall intake pipe, the first intake pipe, the second intake pipe, the third intake pipe, the fourth intake pipe, the first main intake pipe and the first intake pipe The second main intake pipe adopts PU pipe.

A controllable etching method for a combined air intake device with multiple air intake lines, comprising the following steps:

Step 1: place the wafer in a vacuum chamber, the central air inlet of the air storage chamber is located at the center of the wafer, and a plurality of branch air inlets are evenly distributed around the outer periphery of the wafer;

Step 2: start etching the wafer;

Step 3: After etching, measure the thickness of each area of the wafer;

Step 4: When the thickness of the center is too large, open the center air inlet and close all branch air inlets. When the thickness of the area between the wafer center and the edge is too large, open the central air inlet and the branch air inlets on the corresponding side. , close other branch air inlets, when the thickness of the area between the wafer edges is too large, close the central air inlet and open the branch air inlets on the corresponding side;

Step 5: Repeat steps 2 to 4 until the thickness of each area reaches the standard.

As a further preference of the present invention, in step 4, the circle from the center of the wafer to 1/3 of the radial length outward from the center of the circle is the area A, and the circle from the center of the circle from 1/3 of the radius of the radius to 2/3 of the radius of the radius. It is the B area, and the circle from the 2/3 radius of the center to the wafer edge is the C area; divided by the cross line of the wafer center, the B area forms the B1 area, the B2 area, the B3 area, and the B4 area, and the C area forms the C1 area. Area, C2 area, C3 area, C4 area, among which, the B1 area is adjacent to the C1 area, the B2 area is adjacent to the C2 area, the B3 area is adjacent to the C3 area, the B4 area is adjacent to the C4 area, and is close to the C1 area and C2 area. There is a branch air inlet at the central position of the arc in the area, C3 area, and C4 area; when the wafer thickness in area A is too large, the four branch air inlets are closed and the central air inlet is opened; When the thickness of the circle is too large, open the central air inlet and the branch air inlet near the C1 area, and close the other three branch air inlets. The same is true for the B2 area, B3 area, and B4 area; when the wafer thickness in the C1 area is too large When , close the central air inlet, open the branch air inlet near the C1 area, and close the other three branch air inlets. The same is true for the C2 area, the C3 area, and the C4 area.

As a further preference of the present invention, when the wafer thickness of the B1 area and the B2 area is too large, the central air inlet and the two branch air inlets close to the C1 and C2 areas are opened, and the other two branch air inlets are closed. The same is true for the B3 area, B3 area and B4 area, B4 area and B1 area; when the wafer thickness of the C1 area and the C2 area is too large, close the central air inlet and open the two branches close to the C1 area and the C2 area For the air inlet, close the other two branch air inlets, the same is true for the C2 area and the C3 area, the C3 area and the C4 area, and the C4 area and the C1 area.

The present invention has the following beneficial effects:

1. There are multiple air inlet pipelines and branch air inlets, which can ensure the uniformity of the wafer during etching.

2. Multiple pipelines for air intake and equipped with diaphragm valves, which can adjust the local air intake concentration and facilitate local etching of the wafer.

Description of drawings

Fig. 1 is the overall structure schematic diagram of the present invention;

Fig. 2 is the system structure schematic diagram of the present invention;

FIG. 3 is an area division diagram of a wafer;

Among them are: 1. Vacuum chamber; 2. Upper chamber cover; 3. Branch air inlet; 4. Gas cabinet; ; 8. Center air inlet; 9. Intake diaphragm valve; 10. First intake pipe; 11. Second intake pipe; 12. Third intake pipe; 13. Fourth intake pipe; 14. First main intake pipe ; 15. Second main intake pipe; 16. Diaphragm valve; 17. Window; 18. RF capacitor; 19. RF coil; 20. Upper chamber cover handle; 21. Wafer.

Detailed ways

The present invention will be described in further detail below with reference to the accompanying drawings and specific preferred embodiments.

In the description of the present invention, it should be understood that the orientation or positional relationship indicated by the terms "left side", "right side", "upper", "lower part", etc. are based on the orientation or positional relationship shown in the drawings, only For the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the referred device or element must have a particular orientation, be constructed and operate in a particular orientation, "first", "second", etc. importance, and therefore should not be construed as a limitation to the present invention. The specific dimensions used in this embodiment are only for illustrating the technical solution, and do not limit the protection scope of the present invention.

As shown in Figure 1-2, a controllable multi-air intake pipeline combined air intake device, the air intake device is arranged above the vacuum chamber 1, and includes a total air intake mechanism, a split air intake mechanism and an upper chamber cover 2; the upper chamber cover 2; The chamber cover 2 is covered on the vacuum chamber 1 to ensure the sealing of the vacuum chamber 1, and the upper chamber cover 2 is provided with a plurality of branch air inlets 3, and the upper chamber cover 2 is provided with a central air inlet 8. A plurality of branch air inlets 3 and a central air inlet 8 are arranged on the upper cavity cover 2 to facilitate uniform etching of the wafer 21;

The total air intake mechanism includes: a gas cabinet 4, a first total air intake pipeline 5, a second total air intake pipeline 6, an air storage cavity 7, a central air inlet 8 and an air intake diaphragm valve 9; the first total air intake pipeline 5 One end is connected to the gas cabinet 4, the first general air intake pipeline 5 realizes the transportation of gas from the gas cabinet 4 to the split air intake mechanism, one end of the second general air intake pipeline 6 is connected to the first general air intake pipeline 5, and the other end is connected to On the air storage chamber 7, the second total air intake pipeline 6 realizes the gas from the gas cabinet 4 to the air storage chamber 7, and the second total air intake pipeline 6 is provided with an air intake diaphragm valve 9, which can realize the air intake diaphragm valve 9. The switch for gas entering the air storage cavity 7; the air storage cavity 7 is arranged on the central air inlet 8, and the air storage cavity 7 is arranged on the central air inlet 8, which is conducive to the uniform delivery of gas to the split air intake mechanism;

The split air intake mechanism includes: a first intake pipe 10, a second intake pipe 11, and a first main intake pipe 14; one end of the first intake pipe 10 and the second intake pipe 11 are jointly connected to one end of the first main intake pipe 14, The other ends of the first air intake pipe 10 and the second air intake pipe 11 are connected to the edge of the upper chamber cover 2 through the branch air inlet 3, and the other end of the first main air intake pipe 14 is connected to the other end of the first general air intake pipe 5, Diaphragm valves 16 are provided on the first intake pipe 10 and the second intake pipe 11, and the first main intake pipe 14 is connected to the first general intake pipe 5, so as to realize the gas supply to the first intake pipe 10 and the second intake pipe 11. The first gas inlet pipe 10 and the second gas inlet pipe 11 are connected to the branch gas inlet 3, so that the gas is transported into the vacuum chamber 1, and the wafer 21 is etched.

In this embodiment, there may be a plurality of split air intake mechanisms, and the intake can be carried out through a plurality of branch air inlets 3, so that the etching of the wafer 21 is more accurate and uniform. For example, the split air intake mechanism further includes: a third The intake pipe 12 , the fourth intake pipe 13 , the second main intake pipe 15 , one end of the third intake pipe 12 and the fourth intake pipe 13 are jointly connected to one end of the second main intake pipe 15 , the third intake pipe 12 and the fourth intake pipe 13 The other end of the air intake pipe 13 is connected to the edge of the upper chamber cover 2 through the branch air inlet 3 , the other end of the second main air intake pipe 15 is connected to the first general air intake pipe 5 , the third air intake pipe 12 and the fourth air intake pipe 13 There is a diaphragm valve 16 on it.

The intake diaphragm valve 9 and the diaphragm valve 16 are pneumatic valves, driven by cellulose diacetate or N ₂ gas pressure, with simple structure and low cost.

It also includes a solenoid valve, the diaphragm valve 16 and the intake diaphragm valve 9 are connected to the solenoid valve, and the solenoid valve is controlled and switched by the PLC; the PLC is connected to the upper computer and can be controlled by software.

The upper cavity cover 2 is provided with a circular groove, and a window 17 is arranged in the circular groove for installing a radio frequency coil 19; it also includes a radio frequency capacitor 18 and a radio frequency coil 19, and the radio frequency coil 19 is a threaded spiral structure, similar to a mosquito coil shape, The radio frequency capacitor 18 is placed in the window 17, and the radio frequency capacitor 18 is connected to the radio frequency coil 19. When etching or coating is performed, the radio frequency coil 19 and the radio frequency capacitor 18 are activated, and a high frequency electric field is generated by the radio frequency coil 19 to ionize the gas entering the vacuum chamber 1. .

The material of the window 17 is an insulating material, preferably ceramic; the first general air intake pipe 5, the second general air intake pipe 6, the first air intake pipe 10, the second air intake pipe 11, the third air intake pipe 12, the fourth The intake pipe 13 , the first main intake pipe 14 and the second main intake pipe 15 need to transport cellulose diacetate or N ₂ , and need to use anti-corrosion pipes, preferably PU pipes.

The upper cavity cover handle 20 is also provided, and the upper cavity cover handle 20 is arranged on both sides of the upper cavity cover 2 to facilitate the disassembly and placement of the upper cavity cover 2 .

In this embodiment, there are multiple intake pipelines and branch intake ports 3, which can ensure the uniformity of the wafer 21 during etching; and multiple pipelines are equipped with a diaphragm valve 16 for intake air, which can adjust the local intake air concentration. This facilitates local etching of the wafer 21 .

working principle:

When working: firstly open the intake diaphragm valve 9 and all diaphragm valves 16, perform etching or coating, start the radio frequency, generate a high frequency electric field through the radio frequency coil 19, and ionize the gas entering the vacuum chamber 1. Then close the intake diaphragm valve 9 and all diaphragm valves 16, open the vacuum chamber 1, and measure the thickness of the wafer 21. If the measurement result needs to be partially reprocessed, it can be adjusted by the intake method, and only a certain diaphragm is opened. The valve 16 etches the wafer 21 and closes the other diaphragm valves 16 .

The number of intake lines and diaphragm valves 16 can be increased or decreased according to requirements, not limited to the five intake lines and diaphragm valves 16 in Figure 1-2 above. Driven by CDA or nitrogen gas pressure, the drive of the diaphragm valve 16 The pipeline is connected to the electrical integrated solenoid valve, the solenoid valve is controlled and disconnected by the PLC, and the PLC is connected to the upper computer and controlled by software.

As shown in FIG. 3 , an etching method for a controllable multi-intake pipeline combined air intake device includes the following steps:

Step 1: The wafer 21 is placed in the vacuum chamber 1, the central air inlet 8 of the air storage chamber 7 is located at the center of the wafer 21, and a plurality of branch air inlets 3 are evenly distributed around the circumference of the wafer 21; The area around the 21 is covered by the branch air inlets 3 , and with the central air inlet 8 , the wafer 21 can be etched in all directions.

Step 2: start etching the wafer 21, and the etching process is a conventional process.

Step 3: After etching, measure the thickness of each area of the wafer 21. If there is a problem of excessive local thickness, keep the original orientation and put the wafer 21 back;

Step 4: Adjust the etching process:

When the central thickness is too large, open the central air inlet 8 and close all branch air inlets 3;

When the thickness of the area between the center and the edge of the wafer 21 is too large, the central air inlet 8 and the branch air inlets 3 on the corresponding side are opened, and the other branch air inlets 3 are closed;

When the thickness of the area between the edges of the wafer 21 is too large, close the central air inlet 8 and open the branch air inlets 3 on the corresponding side;

Step 5: Repeat steps 2 to 4 until the thickness of each area reaches the standard.

Specifically, in step 4, the circle from the center of the wafer 21 to 1/3 of the radius from the center is the area A, and the circle from the center of the circle from 1/3 of the radius to 2/3 of the radius is B. Area, the circle from the 2/3 radius from the center to the edge of the wafer 21 is the C area; divided by the cross line at the center of the wafer 21, the B area forms the B1 area, the B2 area, the B3 area, and the B4 area, and the C area forms the C1 area. Area, C2 area, C3 area, C4 area, among which, the B1 area is adjacent to the C1 area, the B2 area is adjacent to the C2 area, the B3 area is adjacent to the C3 area, the B4 area is adjacent to the C4 area, and is close to the C1 area and C2 area. There is a branch air inlet 3 in the arc-shaped central position of the region, the C3 region, and the C4 region. The wafer 21 is divided into nine small regions in total, and optimized trimming and etching can be performed for local areas to improve the overall etching effect.

When the thickness of the wafer 21 in the A area is too large, the four branch air inlets 3 are closed, and the central air inlet 8 is opened, so that the concentration of the etching gas in the A area is increased, and the trimming and etching of the A area is carried out.

When the thickness of the wafer 21 in the B1 region is too large, the central gas inlet 8 and the branch gas inlets 3 near the C1 region are opened, and the other three branch gas inlets 3 are closed to increase the concentration of the etching gas in the B1 region. For the trimming and etching of the B1 region, the same is true for the B2 region, the B3 region, and the B4 region.

When the thickness of the wafer 21 in the C1 area is too large, the central gas inlet 8 is closed, the branch gas inlet 3 near the C1 region is opened, and the other three branch gas inlets 3 are closed to increase the concentration of the etching gas in the C1 region. , for the trimming and etching of the C1 region, the same is true for the C2 region, the C3 region, and the C4 region.

Specifically, when the thickness of the wafer 21 in the B1 area and the B2 area is too large, the central air inlet 8 and the two branch air inlets 3 near the C1 and C2 areas are opened, and the other two branch air inlets 3 are closed. Increase the concentration of the etching gas in the B1 area and the B2 area. For the trim etching of the B1 area and the B2 area, the B2 area and the B3 area, the B3 area and the B4 area, and the B4 area and the B1 area are the same;

When the thickness of the wafer 21 in the C1 area and the C2 area is too large, close the central air inlet 8, open the two branch air inlets 3 near the C1 area and the C2 area, and close the other two branch air inlets 3, so that the The concentration of the etching gas in the C1 area and the C2 area is increased. For the trim etching of the C1 area and the C2 area, the C2 area and the C3 area, the C3 area and the C4 area, and the C4 area and the C1 area are the same.

The preferred embodiments of the present invention have been described in detail above. However, the present invention is not limited to the specific details of the above-mentioned embodiments. Within the scope of the technical concept of the present invention, various equivalent transformations can be made to the technical solutions of the present invention. These equivalent transformations All belong to the protection scope of the present invention.

Claims (10)

1. A controllable multi-air inlet pipeline combined air inlet device is arranged on a vacuum chamber (1), and is characterized in that: comprises a main air inlet mechanism, a shunt air inlet mechanism and an upper cavity cover (2); the upper cavity cover (2) covers the vacuum cavity (1), a plurality of branch air inlets (3) are arranged on the upper cavity cover (2), and a central air inlet (8) is arranged on the upper cavity cover (2);

the total intake mechanism includes: the gas storage device comprises a gas holder (4), a first total gas inlet pipeline (5), a second total gas inlet pipeline (6), a gas storage cavity (7), a central gas inlet (8) and a gas inlet diaphragm valve (9); one end of the first total air inlet pipeline (5) is connected with the air cabinet (4), one end of the second total air inlet pipeline (6) is connected to the first total air inlet pipeline (5), the other end of the second total air inlet pipeline is connected to the air storage cavity (7), and the air inlet diaphragm valve (9) is positioned on the second total air inlet pipeline (6); the gas storage cavity (7) is arranged on the central gas inlet (8);

reposition of redundant personnel air intake mechanism includes: the air inlet device comprises a first air inlet pipe (10), a second air inlet pipe (11) and a first main air inlet pipe (14); one end of a first air inlet pipe (10) and one end of a second air inlet pipe (11) are connected to one end of a first main air inlet pipe (14) together, the other ends of the first air inlet pipe (10) and the second air inlet pipe (11) are connected with the edge of an upper cavity cover (2) through a branch air inlet (3), the other end of the first main air inlet pipe (14) is connected with the other end of a first main air inlet pipeline (5), and diaphragm valves (16) are arranged on the first air inlet pipe (10) and the second air inlet pipe (11).

2. The combined air intake device with the controllable multiple air intake pipelines according to claim 1, characterized in that: reposition of redundant personnel air intake mechanism still includes: third intake pipe (12), fourth intake pipe (13), second main intake pipe (15), the one end of third intake pipe (12) and fourth intake pipe (13) is connected in the one end of second main intake pipe (15) jointly, the other end of third intake pipe (12) and fourth intake pipe (13) is connected with upper cover (2) edge through branch air inlet (3), the other end and the first main air inlet pipeline (5) of second main intake pipe (15) are connected, be equipped with diaphragm valve (16) on third intake pipe (12), fourth intake pipe (13).

3. The controllable multi-intake pipeline combination intake device according to claim 1, wherein: the air inlet diaphragm valve (9) and the air inlet valve are pneumatic valves.

4. The combined air intake device with the controllable multiple air intake pipelines according to claim 1, characterized in that: the upper cavity cover (2) is provided with a circular groove, and a window (17) is arranged in the circular groove.

5. The combined air intake device with the controllable multiple air intake pipelines according to claim 4, characterized in that: the radio frequency capacitor is characterized by further comprising a radio frequency capacitor (18) and a radio frequency coil (19), wherein the radio frequency coil (19) is of a spiral structure and is arranged in the window (17), and the radio frequency capacitor (18) is connected to the radio frequency coil (19).

6. The controllable multi-intake pipeline combination intake device according to claim 4, wherein: the window (17) is made of ceramic; the first total air inlet pipeline (5), the second total air inlet pipeline (6), the first air inlet pipe (10), the second air inlet pipe (11), the third air inlet pipe, (12) the fourth air inlet pipe (13), the first main air inlet pipe (14) and the second main air inlet pipe (15) adopt PU pipes.

7. The combined air intake device with the controllable multiple air intake pipelines according to claim 1, characterized in that: the diaphragm valve (16) and the air inlet diaphragm valve (9) are connected with the solenoid valve, and the solenoid valve is controlled to be switched by a PLC; the PLC is connected to an upper computer.

8. The etching method for the controllable multi-air inlet pipeline combined air inlet device according to any one of claims 1-7, characterized by comprising the following steps:

the method comprises the following steps: the wafer (21) is placed in a vacuum chamber (1), a central air inlet (8) of an air storage cavity (7) is positioned at the circle center of the wafer (21), and a plurality of branch air inlets (3) are evenly distributed outside the periphery of the wafer (21);

step two: starting etching on the wafer (21);

step three: after etching, measuring the thickness of each area of the wafer (21);

step four: when the center thickness is too large, opening the center air inlet (8), closing all the branch air inlets (3), when the thickness of the area between the circle center and the edge of the wafer (21) is too large, opening the center air inlet (8) and the branch air inlets (3) on the corresponding side, closing other branch air inlets (3), when the thickness of the area between the edge of the wafer (21) is too large, closing the center air inlet (8), and opening the branch air inlets (3) on the corresponding side;

step five: and repeating the second step to the fourth step until the thickness of each area reaches the standard.

9. The etching method for controlling the multi-air inlet pipeline combined air inlet device according to claim 8, is characterized in that: in the fourth step, a circle with the radius from the center of the wafer (21) to the outside 1/3 of the center of the circle is taken as an area A, a circle with the radius from the center of the outside 1/3 of the center of the circle to the outside 2/3 of the center of the circle is taken as an area B, and a circle with the radius from the center of the outside 2/3 of the center of the circle to the edge of the wafer (21) is taken as an area C; the wafer (21) is divided by a cross line passing through the center of a circle, a B area forms a B1 area, a B2 area, a B3 area and a B4 area, a C area forms a C1 area, a C2 area, a C3 area and a C4 area, wherein the B1 area is adjacent to the C1 area, the B2 area is adjacent to the C2 area, the B3 area is adjacent to the C3 area, the B4 area is adjacent to the C4 area, and a branch air inlet (3) is respectively arranged at the arc middle position close to the C1 area, the C2 area, the C3 area and the C4 area; when the thickness of the wafer (21) in the area A is too large, the four branch air inlets (3) are closed, and the central air inlet (8) is opened; when the thickness of the wafer (21) in the B1 area is too large, the central air inlet (8) and the branch air inlets (3) close to the C1 area are opened, the other three branch air inlets (3) are closed, and the B2 area, the B3 area and the B4 area are the same; when the thickness of the wafer (21) in the C1 area is too large, the central air inlet (8) is closed, the branch air inlets (3) close to the C1 area are opened, the other three branch air inlets (3) are closed, and the C2 area, the C3 area and the C4 area are the same.

10. The etching method for controlling the multi-air-inlet pipeline combined air inlet device according to claim 9, is characterized in that: when the thickness of the wafer (21) in the B1 area and the B2 area is too large, the central gas inlet (8) and two branch gas inlets (3) close to the C1 area and the C2 area are opened, the other two branch gas inlets (3) are closed, and the B2 area and the B3 area, the B3 area and the B4 area, and the B4 area and the B1 area are the same; when the thickness of the wafer (21) in the C1 area and the C2 area is too large, the central air inlet (8) is closed, two branch air inlets (3) close to the C1 area and the C2 area are opened, the other two branch air inlets (3) are closed, and the C2 area and the C3 area, the C3 area and the C4 area, and the C4 area and the C1 area are the same.

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