Etching system for silicon nitride etching chip

Abstract

The invention relates to an etching system for a silicon nitride etching chip, which comprises an etching bin, an electrode and a clamping type wafer fixer, the first end of the etching bin is provided with an air inlet, the second end of the etching bin is provided with an air outlet, the electrode is positioned in the etching bin, the electrode is provided with a plurality of side surfaces, the side surfaces are inclined surfaces, the clamping type wafer fixer is arranged on the side surfaces, and the air inlet is communicated with the air outlet. A plurality of rotating positions are arranged on the clamping type wafer fixer at intervals, the air flow type purging unit is arranged on the clamping type wafer fixer, the pneumatic unit is arranged on the clamping type wafer fixer and is connected with the rotating positions, and the vacuum unit is connected with the etching bin. According to the etching system for the silicon nitride etching chip, the wafer placement density is improved and the electrode size is reduced in a surrounding deployment mode, the uniformity of electric field distribution can be effectively improved, meanwhile, the etching product can be separated from the groove at a higher speed in a rotating mode, and the size precision and the machining precision of the groove are improved.

Description

Technical Field

[0001] The present application relates to the technical field of chip etching equipment, and in particular to an etching system for etching silicon nitride chips. Background Art

[0002] The main dry etching processes are ion beam etching, plasma etching and reactive ion etching, among which reactive ion etching is the most widely used. Reactive ion etching is a chemical and physical etching process that can very accurately control selectivity, etching profile, etching rate, uniformity and repeatability.

[0003] When performing reactive ion etching, the wafer is generally placed on a horizontal plane, with the electrode located below the wafer. If you want to increase the etching speed, you need to flatten the wafer array and increase the equipment area. However, this will directly lead to uneven electric field distribution, making the etching speed at each position uneven, increasing the difficulty of control, and in terms of deep etching, horizontal placement will cause the product to be unable to quickly detach from the groove, resulting in increased roughness of the inner wall of the groove, and the bottom of the groove may also become rough. Summary of the invention

[0004] The present application provides an etching system for silicon nitride etching chips, which uses a surround deployment method to increase wafer placement density and reduce electrode size, which can effectively improve the uniformity of electric field distribution. At the same time, a rotation method is used to enable the etching products to leave the groove at a faster speed, thereby improving the dimensional accuracy and processing accuracy of the groove.

[0005] The above-mentioned purpose of the present application is achieved through the following technical solutions:

[0006] The present application provides an etching system for etching silicon nitride chips, comprising:

[0007] An etching chamber, wherein an air inlet is provided on a first end of the etching chamber, and an exhaust port is provided on a second end of the etching chamber;

[0008] The electrode is arranged inside the etching chamber, and the electrode has multiple side surfaces, all of which are inclined surfaces;

[0009] A clamping type wafer holder is arranged on the side, and a plurality of rotation positions are arranged at intervals on the clamping type wafer holder;

[0010] An airflow purge unit is provided on the clamping wafer holder;

[0011] A pneumatic unit, which is provided on the clamping wafer holder and connected to the rotating position;

[0012] The vacuum unit is connected to the etching chamber.

[0013] In a possible implementation of the present application, the clamping wafer holder includes:

[0014] A base, wherein a plurality of through holes are arranged at intervals on the base;

[0015] The rotation position is arranged on the through hole.

[0016] In a possible implementation of the present application, the rotation position includes:

[0017] A first rotating ring is arranged on the inner wall of the through hole;

[0018] A second rotating ring, rotatably connected to the first rotating ring;

[0019] A clamping ring, detachably fixed on the second rotating ring;

[0020] Wherein, the pneumatic unit and the second rotating ring are connected by a gear pair.

[0021] In a possible implementation of the present application, a flexible fixer is provided on a surface of the clamping ring adjacent to the second rotating ring, and the flexible fixer includes:

[0022] A pneumatic telescopic actuator is provided on the clamping ring;

[0023] The annular expansion body is arranged on the surface of the clamping ring adjacent to the second rotating ring and is connected to the pneumatic telescopic driver.

[0024] In a possible implementation of the present application, a lifting support unit is further provided on the base, and the lifting support unit is located in contact with the non-etching surface of the wafer.

[0025] In a possible implementation of the present application, the airflow purge unit includes:

[0026] A purge ring, provided on the base;

[0027] The purge chamber and adsorption chamber are both located in the purge ring;

[0028] A purge hole is provided on the inner wall of the purge ring and is connected with the purge bin;

[0029] Adsorption holes are provided on the inner wall of the purge ring and are connected with the adsorption chamber;

[0030] Two air pumps are both arranged on the purge ring and are connected to the purge bin and the adsorption bin respectively.

[0031] In a possible implementation of the present application, the inner wall of the purge ring is divided into a first area and a second area;

[0032] The purge holes are all located in the first area, and the adsorption holes are all located in the second area;

[0033] The purge holes are arranged in parallel.

[0034] In a possible implementation of the present application, the purge hole has multiple output ends, and each output end has a different orientation.

[0035] In a possible implementation of the present application, the number of the purge holes is the same as the number of the adsorption holes;

[0036] The axis of the purge hole and the axis of the corresponding adsorption hole are located on the same straight line. BRIEF DESCRIPTION OF THE DRAWINGS

[0037] Figure 1 It is a structural schematic diagram of an etching system provided in this application.

[0038] Figure 2 This is a schematic diagram of the gas flow path when an etching system provided by the present application is working.

[0039] Figure 3 It is a schematic diagram of an inclined surface on an electrode provided in the present application.

[0040] Figure 4 It is a structural schematic diagram of a clamping wafer holder provided in the present application.

[0041] Figure 5 It is a schematic diagram of the internal structure of a clamping wafer holder provided in the present application.

[0042] Figure 6 It is a structural schematic diagram of a flexible fixer provided in this application.

[0043] Figure 7 It is a structural schematic diagram of an airflow purge unit provided in the present application.

[0044] Figure 8 This is a schematic diagram of the airflow path of an airflow purge unit provided in the present application when it is working.

[0045] In the figure, 1. etching chamber, 2. electrode, 3. clamping wafer holder, 4. airflow purge unit, 5. pneumatic unit, 6. vacuum unit, 7. flexible holder, 8. lifting support unit, 11. air inlet, 12. exhaust port, 21. side, 31. base, 32. through hole, 33. rotating position, 71. pneumatic telescopic driver, 72. annular expansion body, 41. purge ring, 42. purge chamber, 43. adsorption chamber, 44. purge hole, 45. adsorption hole, 46. air pump, 331. first rotating ring, 332. second rotating ring, 333. clamping ring. DETAILED DESCRIPTION

[0046] The technical solution in this application is further described in detail below in conjunction with the accompanying drawings.

[0047] The present application discloses an etching system for silicon nitride etching chips. In some examples, the etching system for silicon nitride etching chips disclosed in the present application includes an etching chamber 1, an electrode 2, a clamping wafer holder 3, an airflow purge unit 4, a pneumatic unit 5 and a vacuum unit 6. The electrode 2 is deployed inside the etching chamber 1, specifically, fixedly installed on the bottom surface of the etching chamber 1. The vacuum unit 6 is connected to the etching chamber 1, and its function is to extract the gas inside the etching chamber 1, because only in this way can the specified type of gas be filled into the etching chamber 1 to complete the etching.

[0048] The specific principle of reactive ion etching is as follows:

[0049] First, the reaction gas is broken down by radio frequency glow discharge to generate the plasma required for etching. The plasma contains not only positive ions and negative ions, but also free radicals and free electrons that can react with the surface of the etched sample. These active particles react chemically with atoms or molecules on the surface of the material to be etched to form volatile substances or easily removable by-products, thereby achieving the purpose of etching the surface of the sample.

[0050] In addition to chemical reactions, reactive ion etching also uses physical bombardment to achieve efficient and directional material removal. Under the action of the electric field, anions and cations can be ejected toward the surface of the etched sample to physically bombard the sample. This physical bombardment can accelerate the rate of chemical reactions while ensuring the uniformity and directionality of etching. When bombarding the sample surface, high-energy ions can also remove surface products, exposing a clean etching surface, further improving the etching effect.

[0051] That is, reactive ion etching has both physical impact and chemical reaction removal methods.

[0052] See also Figure 1 An air inlet 11 is provided on the first end of the etching chamber 1, and an exhaust port 12 is provided on the second end of the etching chamber 1. The air inlet 11 is used to inject a specified type of gas into the etching chamber 1. The air inlet 11 can also update the specified type of gas inside the etching chamber 1 together with the exhaust port 12. Because the gas will be continuously consumed during the etching process, the products of the etching process also need to be discharged with the help of the exhaust port 12.

[0053] The gas flow path inside the etching chamber 1 is as follows: Figure 2 shown.

[0054] exist Figure 1 and Figure 2 In the figure, the two broken lines connected to the electrode 2 are the power source and the cooling source respectively.

[0055] See also Figure 3The electrode 2 has a plurality of side surfaces 21 , each of which is an inclined surface. The dotted line on the side surface 21 is the installation position of the clamping wafer holder 3 .

[0056] The number of the clamping wafer holders 3 is the same as the number of the side surfaces 21, that is, a clamping wafer holder 3 is installed on each side surface 21. Figure 4 and Figure 5 A plurality of rotating positions 33 are arranged at intervals on the clamping wafer holder 3, and the wafer to be etched is fixed on the rotating position 33. During the etching process, the rotating position 33 rotates slowly or intermittently.

[0057] The clamping wafer holder 3 may be fixed to the electrode 2 using bolts.

[0058] See also Figure 5 The airflow purge unit 4 is arranged on the clamping wafer holder 3, and its function is to purge the etching surface on the wafer so that the product in the etching process can be quickly separated from the wafer.

[0059] The pneumatic unit 5 is also arranged on the clamping wafer holder 3 . The pneumatic unit 5 is connected to the rotating position 31 , and its function is to drive the wafer to rotate through the rotating position 31 .

[0060] In general, the etching system for silicon nitride etching chips provided in the present application adopts a surround deployment method to increase the deployment density of the wafer, thereby achieving full utilization of the space, reducing the size of the electrode 2 while improving the uniformity of the electric field distribution during the etching process, and at the same time using wafer rotation and purge to quickly remove the products remaining in the groove during the etching process, thereby improving the accuracy of the groove.

[0061] In some examples, the clamping wafer holder 3 includes a base 31 and a rotation position 33 . The base 31 is provided with a plurality of through holes 32 at intervals. The rotation position 33 is disposed on the through holes 32 . Specifically, the rotation position 33 is connected to the inner wall of the through holes 32 .

[0062] The rotating part 33 consists of a first rotating ring 331 , a second rotating ring 332 and a clamping ring 333 . The first rotating ring 331 is fixedly connected to the inner wall of the through hole 32 , the second rotating ring 332 is rotatably connected to the first rotating ring 331 , and the clamping ring 333 is detachably fixed to the second rotating ring 332 .

[0063] The edge of the wafer is located between the second rotating ring 332 and the pressing ring 333 .

[0064] The pneumatic unit 5 is connected to the second rotating ring 332 by a gear pair. The pneumatic unit 5 generally uses a pneumatic motor. A gear is installed on the rotating shaft of the pneumatic motor and the second rotating ring 332 respectively. The two gears are meshed, so that when the pneumatic unit 5 is activated, the second rotating ring 332 will also start to rotate.

[0065] See also Figure 6 A flexible fixture 7 is provided on the surface of the clamping ring 333 adjacent to the second rotating ring 332. The function of the flexible fixture 7 is to apply pressure to the edge of the wafer to fix the wafer. The flexible fixture 7 can provide a flexible fixing method to avoid damage such as wear and cracking of the wafer surface caused by rigid contact.

[0066] The flexible holder 7 consists of two parts: a pneumatic telescopic driver 71 and an annular expansion body 72. The pneumatic telescopic driver 71 is fixedly mounted on the clamping ring 333. The annular expansion body 72 is located on the surface of the clamping ring 333 adjacent to the second rotating ring 332 and is connected to the pneumatic telescopic driver 71.

[0067] In some possible implementations, the pneumatic telescopic driver 71 uses a cylinder, and when the cylinder is extended or retracted, the volume of the annular expansion body 72 is adjusted.

[0068] In some possible implementations, the annular expansion body 72 is adhered to the clamping ring 333 .

[0069] In some possible implementations, a MEMS pressure sensor is attached to the annular expansion body 72, and the working length, that is, the telescopic amount, of the pneumatic telescopic actuator 71 is adjusted by the contact pressure between the MEMS pressure sensor and the edge of the wafer.

[0070] For some examples, see Figure 5 A lifting support unit 8 is also provided on the base 3. The lifting support unit 8 is located in contact with the non-etching surface of the wafer. Generally speaking, the lifting support unit 8 consists of a linear unit and a circular plate. The linear unit drives the circular plate to complete the lifting action.

[0071] In some possible implementations, a MEMS pressure sensor is attached to the circular plate, and the working length of the linear unit is adjusted by the contact pressure between the circular plate and the wafer.

[0072] For the flexible fixture 7 and the lifting support unit 8, both are adjusted when the wafer is placed, and the power is cut off after the adjustment to avoid being affected by the electric field during the etching process. Here, the flexible fixture 7 and the lifting support unit 8 are required to have a self-locking function.

[0073] Both the flexible holder 7 and the lifting support unit 8 are provided with reserved interfaces. When placing the wafer, the clamping wafer holder 3 is taken out from the etching chamber 1 and connected to the interface. After the wafer placement action is completed, the interface is disconnected.

[0074] In some examples, the clamping wafer holder 3 is provided with an airflow purge unit 4, and the airflow purge unit 4 is used to accelerate the detachment of etching products in the grooves by means of airflow.

[0075] See also Figure 5 , Figure 7 and Figure 8 The airflow purge unit 4 includes a purge ring 41, a purge bin 42, an adsorption bin 43 and an air pump 46. The purge ring 41 is fixed on the first rotating ring 331. The purge bin 42 and the adsorption bin 43 are both located in the purge ring 41 and are two independent bin bodies.

[0076] The purge hole 44 is located on the inner wall of the purge ring 41 and is connected to the purge chamber 42. Its function is to output the purge gas to the wafer surface. The adsorption hole 45 is also located on the inner wall of the purge ring 41 and is connected to the adsorption chamber 43. Its function is to collect the purge gas.

[0077] The purpose of using the adsorption holes 45 is to prevent the purge gas from staying above the wafer for too long, causing the etching products to return to the grooves on the wafer.

[0078] Both air pumps 46 are installed on the purge ring 41 and are connected to the purge chamber 42 and the adsorption chamber 43 respectively. The air pump 46 connected to the purge ring 41 directly extracts gas from the inside of the etching chamber 1, and the air pump 46 connected to the adsorption chamber 43 directly returns the gas to the etching chamber 1. This part of the gas is finally discharged through the exhaust port 12.

[0079] In some examples, the inner wall of the purge ring 41 is divided into a first area and a second area, the purge holes 44 are all located in the first area, and the adsorption holes 45 are all located in the second area, so as to avoid interference between the purge holes 44 and the adsorption holes 45.

[0080] The purge holes 44 are also arranged in parallel to avoid mutual interference between the purge holes 44 .

[0081] In some possible implementations, the purge hole 44 has multiple output ends, and each output end has a different orientation, so that the purge hole 44 can have a higher coverage of the wafer.

[0082] In some possible implementations, the number of purge holes 44 is the same as the number of adsorption holes 45, and the axis of the purge hole 44 is on the same straight line as the axis of the corresponding adsorption hole 45, so that the purge gas blown out from the purge hole 44 can quickly leave from above the wafer.

[0083] The embodiments of this specific implementation method are all preferred embodiments of the present application, and are not intended to limit the protection scope of the present application. Therefore, all equivalent changes made based on the structure, shape, and principle of the present application should be included in the protection scope of the present application.

Claims

1. An etching system for etching silicon nitride chips, characterized in that: include: An etching chamber (1), wherein an air inlet (11) is provided at a first end of the etching chamber (1), and an exhaust port (12) is provided at a second end of the etching chamber (1); An electrode (2) is arranged inside the etching chamber (1), and the electrode (2) has a plurality of side surfaces (21), and the side surfaces (21) are all inclined surfaces; A clamping type wafer fixture (3) is arranged on the side surface (21), and a plurality of rotation positions (33) are arranged at intervals on the clamping type wafer fixture (3); An airflow purge unit (4) is arranged on the clamping wafer holder (3); A pneumatic unit (5) is disposed on the clamping wafer holder (3) and connected to the rotating position (31); The vacuum unit (6) is connected to the etching chamber (1).

2. The etching system for etching silicon nitride chips according to claim 1, characterized in that: The clamping wafer holder (3) comprises: A base (31), wherein a plurality of through holes (32) are arranged at intervals on the base (31); The rotation position (33) is arranged on the through hole (32).

3. The etching system for etching silicon nitride chips according to claim 2, characterized in that: The rotation position (33) comprises: A first rotating ring (331) is arranged on the inner wall of the through hole (32); A second rotating ring (332) is rotatably connected to the first rotating ring (331); A clamping ring (333) is detachably fixed on the second rotating ring (332); The pneumatic unit (5) and the second rotating ring (332) are connected by a gear pair.

4. The etching system for etching silicon nitride chips according to claim 3, characterized in that: A flexible fixer (7) is provided on the surface of the clamping ring (333) adjacent to the second rotating ring (332), and the flexible fixer (7) comprises: A pneumatic telescopic driver (71) is provided on the clamping ring (333); The annular expansion body (72) is arranged on the surface of the clamping ring (333) adjacent to the second rotating ring (332) and is connected to the pneumatic telescopic driver (71).

5. The etching system for etching silicon nitride chips according to claim 3, characterized in that: A lifting support unit (8) is also provided on the base (31), and the lifting support unit (8) is located in contact with the non-etching surface of the wafer.

6. The etching system for etching silicon nitride chips according to claim 3, characterized in that: The airflow purge unit (4) comprises: A purge ring (41) is disposed on the base (31); The purge chamber (42) and the adsorption chamber (43) are both arranged in the purge ring (41); A purge hole (44) is provided on the inner wall of the purge ring (41) and is connected to the purge chamber (42); An adsorption hole (45) is provided on the inner wall of the purge ring (41) and is connected to the adsorption bin (43); Two air pumps (46) are both arranged on the purge ring (41) and are respectively connected to the purge bin (42) and the adsorption bin (43).

7. The etching system for etching silicon nitride chips according to claim 6, characterized in that: The inner wall of the purge ring (41) is divided into a first area and a second area; The purge holes (44) are all located in the first area, and the adsorption holes (45) are all located in the second area; The purge holes (44) are arranged in parallel.

8. The etching system for etching silicon nitride chips according to claim 7, characterized in that: The purge hole (44) has a plurality of output ends, and each output end has a different orientation.

9. The etching system for etching silicon nitride chips according to claim 7, characterized in that: The number of the purge holes (44) is the same as the number of the adsorption holes (45); The axis of the purge hole (44) and the axis of the corresponding adsorption hole (45) are located on the same straight line.

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