Wafer suction cup structure and preparation process

Abstract

The present invention relates to the field of wafer suction cup preparation technology, specifically, to a wafer suction cup structure and preparation process. It includes a support table fixedly installed on the lower surface of an adsorption plate, a through hole is provided at the center of the upper surface of the support table, docking holes are provided around the outer surface of the through hole, grooves are provided around the periphery of the upper surface of the support table, an air duct is fixedly connected to one side of the inner side of the groove, an air inlet groove is provided at the inner center of the support table, an air guide pipe is fixedly connected around the lower surface of the inner wall of the air inlet groove, and an air guide groove is provided on one side of the surface of the air guide pipe. An air pressure difference is formed, and the air guide pipes are distributed around the surface of the support table, and are connected to the lower surface of the wafer through the adsorption plate and the air suction hole. At the same time, the air guide pipes are away from the outer wall of the lower surface of the wafer, which can fix the wafer tightly on the upper surface of the adsorption plate, and effectively avoid the pulling force that may cause tiny cracks or breakage on the edge, causing damage to the wafer, thereby ensuring the normal production of the wafer.

Description

Technical Field

[0001] The present invention relates to the technical field of wafer suction cup preparation, and in particular to a wafer suction cup structure and a preparation process. Background Art

[0002] As the semiconductor manufacturing industry is booming, wafers, as the basic materials for chip manufacturing, have strict requirements on precision, stability and cleanliness in their processing, testing and transportation, and wafer suction cups play a vital role in the entire process.

[0003] The conventional technology for preparing wafer chucks at present is vacuum adsorption. Through holes of different sizes are opened around the surface of the wafer chuck. The large-diameter through holes are opened in the center of the wafer chuck, and the small-diameter through holes are opened around the wafer chuck. When a vacuum pump is used to extract air from the bottom of the wafer chuck, the gas flowing through the small-diameter through holes is fast, forming a high pressure, and the gas flowing through the large-diameter through holes is slow, forming a low pressure, which firmly adsorbs the wafer on the surface of the wafer chuck. However, the pressure is generated only due to the size of the through hole diameter. Poor adhesion of the wafer to the surface of the suction cup will be affected by other factors. For example, the wafer is not absolutely flat and has microscopic undulations and defects. The uneven adsorption caused by the flatness problem is more prominent, which may cause local displacement or warping of the wafer during processing, seriously affecting the processing accuracy. Especially for some thin wafers or wafers with sensitive edge quality, when the wafer is subjected to photolithography or etching processing, this pulling force may cause tiny cracks or breakage on the edge, which can easily damage the wafer and thus affect the wafer yield. Summary of the Invention

[0004] The purpose of the present invention is to provide a wafer suction cup structure and preparation process to solve the problem in the prior art that for some thin wafers or wafers with sensitive edge quality, when the wafers are subjected to photolithography or etching processing, the pulling force may cause tiny cracks or breakage on the edges, which may easily cause damage to the wafer.

[0005] To achieve the above objectives, one of the objectives of the present invention is to provide a wafer suction cup structure, including an adsorption plate, a support table and a vacuum pump;

[0006] Air inlet holes are opened around the center of the upper surface of the adsorption plate, and air suction holes are opened around the outer periphery of the upper surface of the adsorption plate. A wafer is placed on the upper surface of the adsorption plate;

[0007] The support platform is fixedly mounted on the lower surface of the adsorption plate, a through hole is provided at the center of the upper surface of the support platform, docking holes are provided around the outer surface of the through hole, a groove is provided around the periphery of the upper surface of the support platform, an air duct is fixedly connected to one side of the inner side of the groove, an air inlet groove is provided at the center of the support platform, an air guide tube is fixedly connected around the lower surface of the inner wall of the air inlet groove, and an air guide groove is provided on one side of the surface of the air guide tube;

[0008] A vacuum pump is fixedly installed inside the shell.

[0009] As a further improvement of the present technical solution, the upper surface of the air inlet groove and the through hole are vertically connected, a through groove is provided at the bottom of the air inlet groove, a connecting pipe is fixedly connected around the top of the inner wall of the air inlet groove, an air guide pipe is fixedly connected around the lower surface of the inner wall of the air inlet groove, and a plurality of air guide grooves are provided inside the support platform. The air guide grooves are arranged in a circular array with the center of the circle as the axis, and one end of the air guide groove extends to the interior of the air inlet groove and is connected to an air guide pipe.

[0010] As a further improvement of the present technical solution, there are three docking holes and air ducting holes in total, the three docking holes and the three air ducting holes are correspondingly connected, and the three docking holes are correspondingly connected to the inside of the air inlet groove through a connecting pipe.

[0011] As a further improvement of the present technical solution, the air guide pipes are evenly distributed around the inner bottom of the air inlet groove. The air guide pipes are L-shaped, with the openings facing downward and fixedly connected around the inner bottom of the air inlet groove.

[0012] As a further improvement of the present technical solution, one side of the surface of the air guide groove is connected to the air duct, and the air duct is evenly distributed around the lower surface of the adsorption plate through the groove and is connected to the suction hole.

[0013] As a further improvement of the present technical solution, the diameters of the air guide pipe and the connecting pipe are smaller than the diameter of the air inlet groove.

[0014] As a further improvement of the present technical solution, the air guide tubes are arranged in an axial ring array with the center of the air inlet groove as the axis, and are connected to the through grooves opened below.

[0015] As a further improvement of this technical solution, the vacuum pump is started to draw out the gas inside the air intake groove from top to bottom, the through holes and docking holes transmit the gas to the inside of the air intake groove, and the air guide pipe absorbs the gas transmitted by the air duct and the air guide groove, and transmits it to the inside of the air intake groove through the air guide pipe.

[0016] A second object of the present invention is to provide a preparation process for operating a wafer chuck structure including any one of the above, comprising the following steps:

[0017] S1. Friction-weld a dense-pored nickel-plated suction cup body and a dense-pored gold-plated suction cup base to obtain a welded part (Note: the dense-pored nickel-plated suction cup body is model number DCAB02100, and the dense-pored gold-plated suction cup base is model number DCAB02101).

[0018] S2. After the sealing test of the welded parts is completed, put them into the oven, adjust the temperature to 160℃, and bake for 8 hours, leaving a 0.25mm margin for the shape and 0.25mm margin for the thickness, and make four 8.0H7 process holes;

[0019] S3. Place the welded part with the process holes in the oven, adjust the temperature to 160℃, and bake for 8 hours. Leave 0.1mm on the outer shape and 0.1mm on one side of the thickness. Thread the main body M2.5 and countersink the holes to the required number. Chamfer and protect the appearance. Take out the welded part and confirm its flatness.

[0020] S4. Put it in the oven again, adjust the temperature to 100℃ and keep it for 8 hours, cool it naturally, polish both surfaces, remove the excess symmetrically, reduce the thickness of 20mm to less than 20.20mm, punch micro holes, engrave words, the flatness is 0.005mm, the parallelism is 0.01mm, chamfer, protect the appearance, and do a water flow test on the machine tool to see all the micro holes;

[0021] S5, gold-plating the surface thereof with a thickness of 2 μm and a coating hardness of HV175, thereby obtaining a semi-finished wafer chuck;

[0022] S6. Place the semi-finished wafer suction cup as a whole on the CNC milling machine. The semi-finished wafer suction cup includes a suction plate and a support platform. Use a milling cutter to open a through hole at the center of the support platform surface, passing through the upper and lower ends of the support platform. Open three docking holes around the outer surface of the through hole. Then, open an oblique pipe groove below the three docking holes and extend it into the interior of the through hole.

[0023] S7. A hole groove is opened around the bottom of the inner side of the through hole, and an oblique pipe groove is also opened along one side of the hole groove and extended to the bottom of the through groove to obtain a finished wafer suction cup.

[0024] Compared with the prior art, the present invention has the following beneficial effects:

[0025] The wafer suction cup structure and preparation process are operated by a vacuum pump to extract air from the bottom of the air inlet groove, so that the gas inside the air inlet groove quickly circulates from top to bottom, forming a low air pressure. At the same time, the gas inside the air inlet groove quickly circulates from top to bottom to generate a downward wind force, so that the air duct and the air guide groove absorb the gas around the surface of the support platform, and effectively allow the air duct to introduce the gas absorbed by the air duct and the air guide groove into the air inlet groove. Since the flow speed and amount of gas introduced by the air duct are lower than the flow speed and amount of gas in the air inlet groove, it is higher than the low air pressure inside the air inlet groove, forming an air pressure difference, and the air ducts are distributed around the surface of the support platform, and are connected to the lower surface of the wafer through the adsorption plate and the air suction holes. At the same time, the air ducts are away from the outer wall of the lower surface of the wafer, so that the wafer can be firmly fixed on the upper surface of the adsorption plate, and it can also effectively avoid the pulling force that may cause tiny cracks or damage on the edge, causing damage to the wafer, thereby ensuring normal processing of the wafer. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 Schematic diagram of the adsorption plate structure of the present invention;

[0027] Figure 2 This is a schematic diagram of the connection structure of the adsorption plate, support platform and vacuum pump of the present invention;

[0028] Figure 3 It is a schematic diagram of the support platform structure of the present invention;

[0029] Figure 4 This is a schematic diagram of the connection structure of the docking hole, groove, air duct and air inlet groove of the present invention;

[0030] Figure 5 Schematic diagram of the connection structure of the air duct, air inlet groove, air guide pipe, air guide groove, through groove and vacuum pump of the present invention;

[0031] Figure 6 This is a schematic diagram of the connection structure of the docking hole, air inlet groove, through groove and suction pipe of the present invention;

[0032] Figure 7 Schematic diagram of the gas flow of the adsorption plate, support platform and vacuum pump of the present invention.

[0033] The meaning of each number in the figure is:

[0034] Adsorption plate; 101, air inlet hole; 102, air suction hole;

[0035] Support platform; 201, through hole; 202, docking hole; 203, groove; 204, air duct; 205, air inlet groove; 206, air guide pipe; 207, air guide groove; 208, through groove; 209, connecting pipe;

[0036] 300. Housing; 301. Vacuum pump. DETAILED DESCRIPTION

[0037] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making any creative efforts shall fall within the scope of protection of the present invention.

[0038] See also Figure 1 - Figure 7 As shown, one of the purposes of this embodiment is to provide a wafer suction cup structure, including an adsorption plate 100, a support platform 200 and a shell 300; air inlet holes 101 are opened around the center position of the upper surface of the adsorption plate 100, and air suction holes 102 are opened around the outer periphery of the upper surface of the adsorption plate 100, and a wafer is placed on the upper surface of the adsorption plate 100.

[0039] The support platform 200 is fixedly installed on the lower surface of the adsorption plate 100, and a through hole 201 is opened at the center position of the upper surface of the support platform 200, and docking holes 202 are opened around the outer surface of the through hole 201, and grooves 203 are opened around the outer periphery of the upper surface of the support platform 200, and an air duct 204 is fixedly connected to one side of the inner side of the groove 203. An air intake groove 205 is opened at the center position of the support platform 200, and an air guide pipe 206 is fixedly connected around the lower surface of the inner wall of the air intake groove 205, and an air guide groove 207 is opened on one side of the surface of the air guide pipe 206, and a vacuum pump 301 is fixedly installed inside the outer shell 300.

[0040] It should be noted that the vacuum pump 301 is a miniature vacuum pump, model CJD5-VM7002. A mechanical device is used to make the diaphragm inside the pump perform reciprocating motion, thereby compressing and stretching the air in the fixed volume pump chamber to form a vacuum (negative pressure), and generating a pressure difference between the pump suction port and the external atmospheric pressure. Under the action of the pressure difference, the gas is pressed (sucked) into the pump chamber and then discharged from the exhaust port.

[0041] The air intake hole 101 and the docking hole 202 are correspondingly connected, and the air intake hole 101 and the docking hole 202 are correspondingly connected, and the docking hole 202 is connected to the air inlet groove 205 via the connecting pipe 209. The suction force generated by the rapid extraction of air from top to bottom inside the air inlet groove 205 can introduce the gas at the center position of the surface of the support platform 200 into the air inlet groove 205 via the air intake pipe 204, the air guide groove 207 and the air guide pipe 206. At the same time, the air intake hole 102 and the air intake pipe 204 are correspondingly connected, and the gas on the surface of the support platform 200 is sucked into the air inlet groove 205.

[0042] By placing the wafer on the surface of the adsorption plate 100 and starting the vacuum pump 301, the gas inside the air inlet groove 205 can be extracted from top to bottom, so that the gas can circulate quickly from top to bottom inside the air inlet groove 205, forming a low air pressure. At the same time, the connection between the air guide pipe 206 and the air guide groove 207 is utilized, and one end of the air guide groove 207 is connected to the air guide pipe 204, so that the gas around the surface of the support platform 200 can be sucked into the air inlet groove 205. Since the air guide pipe 206 is L-shaped and opens downward, the air guide groove 207 is also L-shaped and has a certain length and inclination, so that the circulation speed of the gas absorbed by the air guide groove 207 and the air guide pipe 206 around the surface of the support platform 200 is slower than the circulation speed of the gas inside the air inlet groove 205, thereby forming a high pressure.

[0043] Therefore, based on the above structure, combined with Figure 1-Figure 2 As shown, the structure of the support platform 200 is further disclosed. The air inlet groove 205 and the through hole 201 are vertically connected to each other. A through groove 208 is provided at the bottom end of the air inlet groove 205. A connecting pipe 209 is fixedly connected around the top of the inner wall of the air inlet groove 205. A plurality of air guide grooves 207 are provided inside the support platform 200. The air guide grooves 207 are arranged in a circular array with the center of the circle as the axis, and one end of the air guide groove 207 extends to the inside of the air inlet groove 205 and is connected to an air guide pipe 206.

[0044] Furthermore, after the gas inside the air inlet groove 205 is extracted from top to bottom by the vacuum pump 301, the air guide pipe 206 is set to be L-shaped, with the air inlet downward and the direction of the rapid circulation of gas inside the air inlet groove 205 being the same direction, and one end of the air guide pipe 206 is connected to the air guide groove 207, and one end of the air guide groove 207 is connected to the air duct 204. The gas inside the air inlet groove 205 circulates rapidly from top to bottom to generate a downward wind force, so that the air duct 204 and the air guide groove 207 absorb the gas around the surface of the support platform 200, effectively allowing the air guide pipe 206 to introduce the gas absorbed by the air guide pipe 204 and the air guide groove 207 into the air inlet groove 205. They are distributed from top to bottom in a circular array around the surface of the air inlet groove 205, and the diameter of the air guide pipe 206 is smaller than the diameter of the air inlet groove 205. Therefore, the flow rate and speed of the introduced gas are smaller than the flow rate and speed of the gas inside the air inlet groove 205, forming an air pressure difference with the inside of the air inlet groove 205, and the wafer is placed on the upper surface of the adsorption plate 100, and the air inlet holes 101 opened around the surface of the adsorption plate 100 are connected to the docking holes 202 accordingly, and the air inlet holes 101 and the docking holes 202 are connected to each other, and the docking holes 202 are connected to the air inlet groove 205 by the connecting pipe 209, which can effectively fix the wafer tightly on the upper surface of the adsorption plate 100 and process it.

[0045] It should be noted that the grooves 203 are evenly arranged around the upper surface of the support platform 200, and the opening direction of the air duct 204 is consistent with the direction of gas flow inside the air inlet groove 205. When the air duct 204 absorbs the gas around the surface of the support platform 200 and transmits it to the position of the air duct 206 through the air guide groove 207, it can effectively mix with the gas that flows rapidly from top to bottom in the air inlet groove 205. The air guide pipe 206 is also arranged in a ring around the bottom of the inner side of the air inlet groove 205, but because the diameter of the air guide pipe 206 is smaller than that of the air inlet groove 205, the air inlet groove 205 is larger than that of the air inlet groove 205. The diameter is small, and the air guide groove 207 is L-shaped and connected to the air guide pipe 206. Therefore, the gas flow rate and speed introduced into the air inlet groove 205 are smaller than the gas flow rate and speed inside the air inlet groove 205, so that high pressure is formed around the surface of the support table 200, and low pressure is formed on the surface of the air inlet groove 205, thereby forming an air pressure difference. The pressure difference will generate a force on the surface of the object, so that the external high-pressure gas cannot bypass the wafer and enter the low-pressure area, and then this pressure difference can push the wafer to the low-pressure area and make it adsorbed on the surface of the low-pressure area.

[0046] A second object of this embodiment is to provide a process for preparing a wafer chuck structure, comprising the following steps:

[0047] S1. Friction-weld a dense-pored nickel-plated suction cup body and a dense-pored gold-plated suction cup base to obtain a welded part (Note: the dense-pored nickel-plated suction cup body is model number DCAB02100, and the dense-pored gold-plated suction cup base is model number DCAB02101).

[0048] S2. After the sealing test of the welded parts is completed, put them into the oven, adjust the temperature to 160℃, and bake for 8 hours. Leave a 0.25mm margin for the shape and 0.25mm for the thickness. Make four 8.0H7 process holes (H7 means the hole tolerance standard of 8.0mm is +0.015mm).

[0049] S3. Place the welded part with the process holes in the oven, adjust the temperature to 160℃, and bake for 8 hours. Leave 0.1mm on the outer shape and 0.1mm on one side of the thickness. Thread the main body M2.5 and countersink the holes to the required number. Chamfer and protect the appearance. Take out the welded part and confirm its flatness.

[0050] S4. Put it in the oven again, adjust the temperature to 100℃ and keep it for 8 hours, cool it naturally, polish both surfaces, remove the excess symmetrically, reduce the thickness of 20mm to less than 20.20mm, punch micro holes, engrave words, the flatness is 0.005mm, the parallelism is 0.01mm, chamfer, protect the appearance, and do a water flow test on the machine tool to see all the micro holes;

[0051] S5, gold-plating the surface thereof with a thickness of 2 μm and a coating hardness of HV175, thereby obtaining a semi-finished wafer chuck;

[0052] S6. Place the semi-finished wafer suction cup as a whole on the CNC milling machine. The semi-finished wafer suction cup includes an adsorption plate 100 and a support platform 200. Use a milling cutter to open a through hole 201 at the center of the surface of the support platform 200, passing through the upper and lower ends of the support platform 200. Open three docking holes 202 around the outer surface of the through hole 201. Then, open an oblique pipe groove below the three docking holes 202 and extend it into the interior of the through hole 201.

[0053] S7. A hole groove is opened around the inner bottom of the through hole 201, and an oblique pipe groove is also opened along one side of the hole groove and extended to the bottom of the through groove 208 to obtain a finished wafer suction cup.

[0054] The above shows and describes the basic principles, main features, and advantages of the present invention. Those skilled in the art should understand that the present invention is not limited to the above embodiments. The above embodiments and descriptions are merely preferred examples of the present invention and are not intended to limit the present invention. Various changes and improvements may be made to the present invention without departing from the spirit and scope of the present invention. Such changes and improvements fall within the scope of the present invention. The scope of protection claimed in the present invention is defined by the appended claims and their equivalents.

Claims

1. A wafer chuck structure, characterized in that: It comprises an adsorption plate (100), a support platform (200) and a housing (300); Air inlet holes (101) are provided around the center of the upper surface of the adsorption plate (100), and air suction holes (102) are provided around the periphery of the upper surface of the adsorption plate (100). A wafer is placed on the upper surface of the adsorption plate (100); The support platform (200) is fixedly mounted on the lower surface of the adsorption plate (100); a through hole (201) is provided at the center of the upper surface of the support platform (200); docking holes (202) are provided around the outer surface of the through hole (201); a groove (203) is provided around the outer periphery of the upper surface of the support platform (200); an air duct (204) is fixedly connected to one side of the inner side of the groove (203); an air inlet groove (205) is provided at the center of the support platform (200); an air guide tube (206) is fixedly connected to the lower surface of the inner wall of the air inlet groove (205); an air guide groove (207) is provided inside the support platform (200); the air guide grooves (207) are arranged in a circular array with the center of the circle as the axis; one end of the air guide groove (207) extends to the inside of the air inlet groove (205) and is connected to the air guide tube (206); an air guide groove (207) is provided on one side of the surface of the air guide tube (206); The grooves (203) are evenly arranged around the upper surface of the support platform (200), and the opening direction of the air duct (204) is consistent with the gas flow direction inside the air inlet groove (205). The air duct (204) absorbs the gas around the surface of the support platform (200). The air duct (206) is L-shaped and opens downward. The air guide groove (207) is also L-shaped and has a certain length and inclination, so that the gas flow speed of the air guide groove (207) and the air duct (206) on the surrounding surface of the support platform (200) is slower than the gas flow speed inside the air inlet groove (205), forming a high pressure, which is greater than the gas flow speed of the air inlet groove (205), and forming a pressure difference with the inside of the air inlet groove (205); A vacuum pump (301) is fixedly installed inside the housing (300).

2. The wafer chuck structure according to claim 1, wherein: The upper surface of the air inlet groove (205) is vertically connected to the through hole (201), a through groove (208) is provided at the bottom end of the air inlet groove (205), and a connecting pipe (209) is fixedly connected to the top of the inner wall of the air inlet groove (205).

3. The wafer chuck structure according to claim 2, wherein: There are three docking holes (202) and three air inlet holes (101) in total. The three docking holes (202) and the three air inlet holes (101) are correspondingly connected, and the three docking holes (202) are correspondingly connected to the inside of the air inlet groove (205) through the connecting pipe (209).

4. The wafer chuck structure according to claim 2, wherein: The air guide tubes (206) are evenly distributed around the inner bottom of the air inlet groove (205). The air guide tubes (206) are L-shaped, with the opening facing downward and fixedly connected around the inner bottom of the air inlet groove (205).

5. The wafer chuck structure according to claim 1, wherein: One side of the surface of the air guide groove (207) is correspondingly connected to the air guide pipe (204), and the air guide pipe (204) is evenly distributed around the lower surface of the adsorption plate (100) through the groove (203) and is correspondingly connected to the air suction hole (102).

6. The wafer chuck structure according to claim 2, wherein: The diameters of the air guide pipe (206) and the connecting pipe (209) are smaller than the diameter of the air inlet groove (205).

7. The wafer chuck structure according to claim 4, wherein: The air guide tubes (206) are arranged in a circular array with the air inlet groove (205) as the center, and are connected to the through groove (208) opened below.

8. The wafer chuck structure according to claim 2, wherein: The vacuum pump (301) is started to extract the gas inside the air inlet groove (205) from top to bottom, and the through hole (201) and the docking hole (202) transmit the gas to the inside of the air inlet groove (205). The air guide pipe (206) absorbs the gas transmitted by the air guide pipe (204) and the air guide groove (207), and transmits the gas to the inside of the air inlet groove (205) through the air guide pipe (206).

9. A process for preparing the wafer chuck structure according to claim 1, characterized in that: The steps include: S1. Place the semi-finished wafer suction cup as a whole on the CNC milling machine, wherein the semi-finished wafer suction cup includes an adsorption plate (100) and a support table (200), and use a milling cutter to open a through hole (201) at the center position of the surface of the support table (200), passing through the upper and lower ends of the support table (200); S2, opening three more docking holes (202) around the through hole (201), and opening an oblique pipe groove below the three docking holes (202) and extending to the inside of the through hole (201); S3. A hole groove is opened around the bottom of the inner side of the through hole (201), and an oblique pipe groove is also opened along one side of the hole groove and extended to the bottom of the through groove (208), thereby obtaining a finished wafer suction cup.

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