A system and method for pre-treating epitaxial silicon wafers for high uniformity of passivation layer

Abstract

The application discloses an epitaxial silicon wafer pretreatment system and process with high uniformity of passivation layer, a support is fixedly arranged at the bottom of the treatment box, and the application relates to the technical field of silicon wafer pretreatment. The epitaxial silicon wafer pretreatment system and process with high uniformity of passivation layer, through cooperation between the partition plate mechanism, the disturbance plate mechanism, the suction mechanism and the servo motor, the servo motor is started, the suction mechanism is driven to work, the hydrofluoric acid solution in the treatment box is sucked out from the lower part, then is sprayed out through each disturbance plate mechanism, impacts the surface of the adjacent epitaxial silicon wafer, at the same time, the external gas is sucked in, then is blown into the hydrofluoric acid solution through each disturbance plate mechanism, so that the hydrofluoric acid is more uniformly contacted to the surface of the epitaxial silicon wafer, the circulating flowing hydrofluoric acid solution and the inhaled gas are cooperated with each other, the purpose of efficiently removing the oxide and impurities on the surface of the epitaxial silicon wafer is achieved, and the flatness and uniformity of the surface of the epitaxial silicon wafer are ensured.

Description

Technical Field

[0001] This invention relates to the field of silicon wafer pretreatment technology, specifically to an epitaxial silicon wafer pretreatment system and process with high passivation layer uniformity. Background Technology

[0002] In the process of epitaxial silicon wafer fabrication, the high uniformity of the passivation layer is crucial for device performance and process stability. In order to ensure the high uniformity of the passivation layer during the pretreatment of epitaxial silicon wafers, the surface of the epitaxial silicon wafer is usually deoxidized with hydrofluoric acid solution in advance, while removing impurities and ensuring that the contact surface is clean, so that a highly uniform passivation layer can be formed on the surface of the epitaxial silicon wafer afterward, thus ensuring device performance and process stability.

[0003] Referring to a fully automatic, environmentally friendly, recyclable silicon wafer cleaning machine (Chinese Patent Publication No. CN209108769U), the machine utilizes a combination of a first filter plate and a second filter plate to filter wastewater generated by the machine itself. A circulating water pump draws the treated water from the circulating water tank to a storage tank, where it can be reused after natural sedimentation, reducing water waste. The combination of a fixed column, a movable column, a pressure plate, a fixed plate, and a return spring buffers the first filter plate, effectively reducing the impact of water flow on it and protecting the filter plate.

[0004] A comprehensive analysis of the above-mentioned patents reveals the following shortcomings:

[0005] Existing epitaxial silicon wafer pretreatment systems and processes with high passivation layer uniformity typically use hydrofluoric acid solution to pickle the surface of the epitaxial silicon wafer. However, it is difficult to ensure that the hydrofluoric acid fully and uniformly contacts the surface of the epitaxial silicon wafer, resulting in the inability to efficiently remove oxides and impurities from the surface of the epitaxial silicon wafer, affecting the flatness and uniformity of the surface. Therefore, it is necessary to provide an epitaxial silicon wafer pretreatment system and process with high passivation layer uniformity to solve the above-mentioned technical problems. Summary of the Invention

[0006] To address the shortcomings of existing technologies, this invention provides an epitaxial silicon wafer pretreatment system and process with high passivation layer uniformity. This solves the problem that while hydrofluoric acid solution is commonly used for acid washing of epitaxial silicon wafers, it is difficult to ensure that the hydrofluoric acid fully and uniformly contacts the surface of the epitaxial silicon wafer, resulting in the inability to efficiently remove oxides and impurities from the surface of the epitaxial silicon wafer, thus affecting the flatness and uniformity of the epitaxial silicon wafer surface.

[0007] To achieve the above objectives, the present invention provides the following technical solution: an epitaxial silicon wafer pretreatment system with high passivation layer uniformity, comprising:

[0008] A processing box for holding hydrofluoric acid solution. A support is fixedly installed at the bottom of the processing box. A partition mechanism is fixedly installed between the side walls in the middle of the inner cavity of the processing box. Several guide frames are evenly fixed through the bottom of the partition mechanism from left to right.

[0009] If the disturbance plate mechanism is used to spray hydrofluoric acid solution and blow out gas, several disturbance plate mechanisms are uniformly fixedly connected to the top of the partition mechanism.

[0010] A suction mechanism for suctioning hydrofluoric acid solution and gas is provided at the front end of the processing tank.

[0011] Two epitaxial silicon wafer clamping mechanisms are used to clamp epitaxial silicon wafers of different thicknesses. The two epitaxial silicon wafer clamping mechanisms are respectively set on the front and rear walls of the inner cavity of the processing box. Several vertical grooves are evenly opened from left to right on the front and rear walls of the inner cavity of the processing box. Horizontal grooves are opened on both sides of each vertical groove on the front and rear walls of the inner cavity of the processing box. A servo motor is fixedly installed at the front end of the suction mechanism. Two filter screens located below the guide frame are fixedly installed between the side walls of the inner cavity of the processing box. A sealing cover is installed on the left side of the processing box above each filter screen. A discharge pipe is fixedly installed at the bottom left side of the processing box. A valve is fixedly installed on the right side of the discharge pipe.

[0012] Preferably, the partition mechanism includes a partition, with a plurality of liquid passage chambers evenly distributed from left to right on the upper front end of the partition, and a plurality of L-shaped liquid outlet holes distributed from front to back on the top of the partition and directly below each disturbance plate mechanism, wherein the L-shaped liquid outlet holes on the same vertical cross section are connected to adjacent liquid passage chambers. The lower front end of the partition has a plurality of air passage chambers evenly distributed from left to right, and a plurality of L-shaped air outlet holes distributed from front to back on the top of the partition and directly below each disturbance plate mechanism, wherein the L-shaped air outlet holes on the same vertical cross section are connected to adjacent air passage chambers.

[0013] Preferably, each of the disturbance plate mechanisms includes a dividing vertical plate, the bottom of which is fixedly connected to the top of a partition. The dividing vertical plate has several branch liquid chambers evenly distributed from front to back inside, and several branch air chambers evenly distributed from front to back inside. The branch liquid chambers and branch air chambers are interleaved. Each branch liquid chamber is connected to a corresponding L-shaped liquid outlet, and each branch air chamber is connected to a corresponding L-shaped air outlet. Several liquid outlet assemblies are fixedly connected from top to bottom on the side of each branch liquid chamber closest to the guide frame. Several air outlet assemblies are fixedly connected from top to bottom on the side of each branch air chamber closest to the guide frame. The air outlet assemblies are formed by proportionally reducing the size of the liquid outlet assemblies.

[0014] Preferably, the liquid outlet assembly includes a short tube with two grooves on its inner wall. A slider is slidably disposed inside each groove, and a block is fixedly disposed between the two sliders. A confluence cavity is formed in the middle of the end of the block near the branch liquid chamber. A plurality of spray holes are evenly formed around the sidewall of the confluence cavity. The sidewall of the slider is fixedly connected to the sidewall of the groove by a first spring. A semi-circular mesh cover is fixedly disposed at the end of the short tube away from the dividing vertical plate.

[0015] Preferably, the suction mechanism includes a receiving box, which is fixedly connected to the front end of the processing box. The inner cavity of the receiving box is provided with a suction component. An external gear ring is rotatably provided at the rear end of the inner cavity of the receiving box. A plurality of first semicircular blocks are evenly fixedly provided around the inner wall of the external gear ring. A short shaft is rotatably provided between the front and rear walls of the inner cavity of the receiving box. The front end of the short shaft is fixedly connected to the output end of a servo motor. A gear is fixedly sleeved on the outside of the short shaft. The left side of the gear meshes with the right side of the external gear ring.

[0016] Preferably, the suction assembly includes a square block, which is fixedly connected to the rear wall of the inner cavity of the receiving box. A liquid-containing chamber is formed on the left side of the square block, and a gas-containing chamber is formed on the right side. T-shaped pistons are slidably disposed inside both the liquid-containing and gas-containing chambers. The ends of the two T-shaped pistons, which are far apart from each other, slide through to the outside of the square block and are fixedly disposed on a second semicircular block. A second spring is sleeved on the outside of the T-shaped pistons, and the second spring is fixedly connected between the outer wall of the square block and the second semicircular block. The bottom right side of the liquid-containing chamber is fixedly connected to the front wall of the processing box via a liquid suction pipe, and the bottom left side of the gas-containing chamber is fixedly connected to a gas suction pipe. The front end of the suction pipe is fixedly connected through the front wall of the receiving box. A first one-way valve is fixedly installed at the upper part of both the liquid suction pipe and the suction pipe. A drain pipe is fixedly connected to the right side of the front end of the liquid chamber. A horizontal infusion pipe is fixedly connected to the top of the drain pipe. Several infusion branch pipes are evenly fixedly connected to the rear end of the horizontal infusion pipe. Each infusion branch pipe is connected to a corresponding liquid passage chamber. An exhaust pipe is fixedly connected to the left side of the front end of the air chamber. A horizontal gas infusion pipe is fixedly connected to the top of the exhaust pipe. Several horizontal gas infusion branch pipes are evenly fixedly connected to the rear end of the horizontal gas infusion pipe. Each gas infusion branch pipe is connected to a corresponding air passage chamber. A second one-way valve is fixedly installed at the bottom of both the drain pipe and the exhaust pipe.

[0017] Preferably, each of the epitaxial silicon wafer limiting mechanisms includes a plurality of bumps, which are uniformly and fixedly connected to the inner wall of the processing box. A clamping plate assembly is rotatably arranged between adjacent bumps, and a rack and pinion assembly is provided on the outside of each clamping plate assembly.

[0018] Preferably, the clamping plate assembly includes a bidirectional lead screw rotatably connected between two protrusions. A gear plate is fixedly sleeved in the middle of the bidirectional lead screw. Opposite threads are formed on the outer side of the bidirectional lead screw and on both sides of the gear plate. Two collars located on both sides of the gear plate are sleeved on the outer threads of the bidirectional lead screw. Connecting rods are fixedly provided at the upper and lower ends of the collars. A clamping plate is fixedly provided at the end of the connecting rod away from the inner wall of the processing box. Several through holes are evenly formed on the surface of the clamping plate. A limiting rod is fixedly provided at the end of the collar near the inner wall of the processing box. The limiting rod is slidably connected in the corresponding horizontal groove. The rack assembly includes a limiting block slidably connected in the corresponding vertical groove. A rack is fixedly provided at the end of the limiting block near the clamping plate assembly. The side of the rack away from the limiting block meshes with the gear plate. An L-shaped baffle is fixedly provided at the top of the rack. The bottom of the limiting block is fixedly connected to the bottom of the vertical groove by a third spring. A base plate is fixedly provided at the bottom of the rack.

[0019] This invention also provides a pretreatment process for epitaxial silicon wafers with high passivation layer uniformity, employing an epitaxial silicon wafer pretreatment system with high passivation layer uniformity, and the specific method includes the following steps:

[0020] Step 1: Place several epitaxial silicon wafers from left to right between two adjacent clamping plate assemblies. Under the action of the weight of the epitaxial silicon wafers, the rack assembly is pressed down, and the clamping plate assembly completes the clamping and limiting of the epitaxial silicon wafers. At the same time, the epitaxial silicon wafers are immersed in hydrofluoric acid solution. Then, the servo motor is started to drive the gear, external gear ring and the first semicircular block to rotate. During the rotation of the first semicircular block, it cooperates with the second spring to make the second semicircular block and the T-shaped piston reciprocate in the left and right directions.

[0021] Step 2: During the process, using negative pressure, the hydrofluoric acid solution at the bottom of the processing chamber is first drawn into the liquid placement chamber through the liquid extraction pipe, and external gas is drawn into the gas placement chamber through the gas extraction pipe. Then, the hydrofluoric acid solution is pushed into the disturbance plate mechanism through each liquid delivery branch pipe and sprayed into the processing chamber again to impact the surface of the epitaxial silicon wafer. The gas is pushed into the disturbance plate mechanism through each gas delivery branch pipe. Then, gas is introduced into the hydrofluoric acid solution in the processing chamber to make the hydrofluoric acid contact the surface of the epitaxial silicon wafer more evenly, effectively remove oxides and impurities from the surface of the epitaxial silicon wafer, and ensure the flatness and uniformity of the surface of the epitaxial silicon wafer.

[0022] Step 3: As the hydrofluoric acid solution flows downward, internal impurities are intercepted by the filter screen. The filtered hydrofluoric acid solution enters the suction assembly and circulates up and down to complete the acid washing of the epitaxial silicon wafer.

[0023] Preferably, each of the clamping plate assemblies is located between two adjacent disturbance plate mechanisms.

[0024] Beneficial effects

[0025] This invention provides an epitaxial silicon wafer pretreatment system and process with high passivation layer uniformity. Compared with the prior art, it has the following advantages:

[0026] 1. A pretreatment system and process for epitaxial silicon wafers with high passivation layer uniformity, comprising a partition mechanism, a disturbance plate mechanism, a suction mechanism, and a servo motor, wherein starting the servo motor drives the suction mechanism to draw hydrofluoric acid solution from the bottom of the treatment chamber, and then sprays it out through the disturbance plate mechanisms to impact the surface of adjacent epitaxial silicon wafers. At the same time, external gas is drawn in and then blown into the hydrofluoric acid solution through the disturbance plate mechanisms, so that the hydrofluoric acid contacts the surface of the epitaxial silicon wafer more uniformly. The circulating hydrofluoric acid solution and the introduced gas work together to achieve the purpose of efficiently removing oxides and impurities from the surface of the epitaxial silicon wafer, ensuring the flatness and uniformity of the surface of the epitaxial silicon wafer.

[0027] 2. An epitaxial silicon wafer pretreatment system and process with high passivation layer uniformity, through the cooperation of short pipe, plug, nozzle and semi-circular mesh, when the suction mechanism does not deliver hydrofluoric acid solution into the disturbance plate mechanism, under the elastic action of the first spring, the plug is completely located in the short pipe, the nozzle is blocked, and the hydrofluoric acid solution in the treatment box will not directly enter the short pipe. The semi-circular mesh can prevent external impurities from clogging the nozzle. Similarly, when the suction mechanism does not deliver gas into the disturbance plate mechanism, the hydrofluoric acid solution in the treatment box will not enter the gas outlet component, ensuring that the disturbance plate mechanism can normally drain liquid and gas.

[0028] 3. An epitaxial silicon wafer pretreatment system and process with high passivation layer uniformity, which achieves the purpose of simultaneously pumping hydrofluoric acid solution and gas by means of the mutual cooperation between the suction component, the external gear ring, the first semicircular block and the gear, and only requires one servo motor to drive the mechanism, without the need for multiple pumps, thus saving energy and reducing production costs.

[0029] 4. An epitaxial silicon wafer pretreatment system and process with high passivation layer uniformity, which utilizes the interaction between a bidirectional lead screw, a toothed disc, clamping plates, a rack, and a base plate to utilize the weight of the epitaxial silicon wafer itself. During the downward pressing of the base plate, the rack is pushed down, thereby causing the toothed disc and the bidirectional lead screw to rotate. The rotation of the bidirectional lead screw causes the two collars to move closer together, that is, the clamping plates on the left and right sides to move closer together, thereby automatically clamping and limiting the epitaxial silicon wafer, so as to quickly enter the acid washing stage. The operation is convenient and the pretreatment efficiency is improved. Attached Figure Description

[0030] Figure 1 This is a perspective view of the present invention;

[0031] Figure 2This is a partial cross-sectional view of the present invention;

[0032] Figure 3 This is a partial cross-sectional view of the processing box of the present invention;

[0033] Figure 4 This is a schematic diagram showing the connection state between the processing box and the epitaxial silicon wafer limiting mechanism of the present invention;

[0034] Figure 5 This is a perspective view of the processing box of the present invention;

[0035] Figure 6 This is a schematic diagram showing the connection state of the partition mechanism and the suction mechanism of the present invention;

[0036] Figure 7 This is a perspective view of the partition mechanism of the present invention;

[0037] Figure 8 This is a first sectional view of the partition mechanism of the present invention;

[0038] Figure 9 This is a second sectional view of the partition mechanism of the present invention;

[0039] Figure 10 This is a perspective view of the disturbance plate mechanism of the present invention;

[0040] Figure 11 This is a cross-sectional view of the disturbance plate mechanism of the present invention;

[0041] Figure 12 This is an exploded view of the liquid outlet assembly of the present invention;

[0042] Figure 13 This is a cross-sectional view of the blocking block of the present invention;

[0043] Figure 14 This is an exploded view of the suction mechanism of the present invention;

[0044] Figure 15 This is an exploded view of the suction component of the present invention;

[0045] Figure 16 This is a cross-sectional perspective view of the square block of the present invention;

[0046] Figure 17 This is a perspective view of the epitaxial silicon wafer limiting mechanism of the present invention;

[0047] Figure 18 This is a perspective view of the clamping plate assembly of the present invention;

[0048] Figure 19 This is a perspective view of the rack assembly of the present invention.

[0049] In the diagram: 1. Processing box; 2. Support; 3. Baffle mechanism; 31. Baffle; 32. Liquid passage chamber; 33. L-shaped liquid outlet; 34. Ventilation chamber; 35. L-shaped air outlet; 4. Guide frame; 5. Disturbance plate mechanism; 51. Separating vertical plate; 52. Branch liquid chamber; 53. Branch air chamber; 54. Liquid outlet assembly; 541. Short pipe; 542. Slide groove; 543. Slider; 544. Block; 545. Merging chamber; 546. Spray hole; 547. First spring; 548. Semicircular mesh cover; 55. Air outlet assembly; 6. Suction mechanism; 61. Receiving box; 62. Suction assembly; 621. Square block; 622. Liquid placement chamber; 623. Air placement chamber; 624. T-shaped piston; 625. Second semicircular block; 626. Second spring; 627. Liquid suction pipe; 628. Air suction pipe 629. First check valve; 6210. Drain pipe; 6211. Infusion horizontal pipe; 6212. Infusion branch pipe; 6213. Exhaust pipe; 6214. Gas horizontal pipe; 6215. Gas branch pipe; 6216. Second check valve; 63. External gear ring; 64. First semicircular block; 65. Short shaft; 66. Gear; 7. Epitaxial silicon wafer limiting mechanism; 71. Bump; 72. Clamping plate assembly; 721. Double-acting lead screw; 722. Gear plate; 723. Collar; 724. Connecting rod; 725. Clamping plate; 726. Limiting rod; 73. Rack assembly; 731. Limiting block; 732. Rack; 733. L-shaped baffle; 734. Third spring; 735. Base plate; 8. Vertical groove; 9. Horizontal groove; 10. Servo motor; 11. Filter screen; 12. Sealing cover; 13. Discharge pipe. Detailed Implementation

[0050] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0051] This invention provides two technical solutions:

[0052] like Figures 1-6 A first embodiment is shown: an epitaxial silicon wafer pretreatment system with high passivation layer uniformity, comprising:

[0053] The processing box 1 is used to hold hydrofluoric acid solution. A support 2 is fixedly installed at the bottom of the processing box 1. A partition mechanism 3 is fixedly installed between the side walls in the middle of the inner cavity of the processing box 1. Several guide frames 4 are evenly fixed through the bottom of the partition mechanism 3 from left to right.

[0054] If the moving plate mechanism 5 is used to spray out hydrofluoric acid solution and blow out gas, the moving plate mechanism 5 is uniformly and fixedly connected to the top of the partition mechanism 3.

[0055] The suction mechanism 6 is used to suction hydrofluoric acid solution and gas, and the suction mechanism 6 is located at the front end of the processing tank 1.

[0056] Two epitaxial silicon wafer limiting mechanisms 7 are used to clamp epitaxial silicon wafers of different thicknesses. The two epitaxial silicon wafer limiting mechanisms 7 are respectively set on the front and rear walls of the inner cavity of the processing box 1. Several vertical grooves 8 are evenly opened from left to right on the front and rear walls of the inner cavity of the processing box 1. Horizontal grooves 9 are opened on both sides of each vertical groove 8 on the front and rear walls of the inner cavity of the processing box 1. A servo motor 10 is fixedly installed at the front end of the suction mechanism 6. Two filter screens 11 located below the guide frame 4 are fixedly installed between the side walls of the inner cavity of the processing box 1. A sealing cover 12 is installed on the left side of the processing box 1 above each filter screen 11. A discharge pipe 13 is fixedly installed at the bottom left side of the processing box 1. A valve is fixedly installed on the right side of the discharge pipe 13.

[0057] Through the cooperation of the partition mechanism 3, the disturbance plate mechanism 5, the suction mechanism 6, and the servo motor 10, starting the servo motor 10 drives the suction mechanism 6 to work, drawing the hydrofluoric acid solution in the processing box 1 out from the bottom, and then spraying it out through each disturbance plate mechanism 5 to impact the surface of the adjacent epitaxial silicon wafer. At the same time, external gas is drawn in and then blown into the hydrofluoric acid solution through each disturbance plate mechanism 5, so that the hydrofluoric acid contacts the surface of the epitaxial silicon wafer more evenly. The circulating hydrofluoric acid solution and the introduced gas work together to achieve the purpose of efficiently removing oxides and impurities from the surface of the epitaxial silicon wafer, ensuring the flatness and uniformity of the surface of the epitaxial silicon wafer.

[0058] like Figures 7-19The second embodiment is shown, the main difference from the first embodiment being: an epitaxial silicon wafer pretreatment system with high passivation layer uniformity, wherein the partition mechanism 3 includes a partition 31, a plurality of liquid passage chambers 32 are evenly opened from left to right on the upper front end of the partition 31, a plurality of L-shaped liquid outlet holes 33 are opened from front to back on the top of the partition 31 and directly below each disturbance plate mechanism 5, and the L-shaped liquid outlet holes 33 of the same vertical cross section are connected to adjacent liquid passage chambers 32, a plurality of venting chambers 34 are evenly opened from left to right on the lower front end of the partition 31, and a plurality of L-shaped venting holes 35 are opened from front to back on the top of the partition 31 and directly below each disturbance plate mechanism 5, and the L-shaped venting holes 35 of the same vertical cross section are connected to adjacent venting chambers 34, and the L-shaped venting holes 35 of the same vertical cross section are connected to adjacent venting chambers 34, and the L-shaped venting holes 35 of the same vertical cross section are connected to adjacent venting chambers 34, and the L-shaped venting holes 35 of the same vertical cross section are connected to adjacent venting chambers 32, and the L-shaped venting holes 34 of the same vertical cross section are connected to adjacent venting chambers 32 ... The liquid holes 33 and L-shaped air outlets 35 are interleaved. Each disturbance plate mechanism 5 includes a dividing vertical plate 51. The bottom of the dividing vertical plate 51 is fixedly connected to the top of the partition plate 31. Several branch liquid chambers 52 and several branch air chambers 53 are evenly opened from front to back inside the dividing vertical plate 51. The branch liquid chambers 52 and several branch air chambers 53 are interleaved. The branch liquid chambers 52 are connected to the corresponding L-shaped liquid outlets 33, and the branch air chambers 53 are connected to the corresponding L-shaped air outlets 35. Several liquid outlet components 54 are fixedly connected from top to bottom on the side of each branch liquid chamber 52 near the guide frame 4. Several air outlet components 55 are fixedly connected from top to bottom on the side of each branch air chamber 53 near the guide frame 4. The air outlet assembly 55 is formed by proportionally reducing the size of the liquid outlet assembly 54. The liquid outlet assembly 54 includes a short tube 541. Two grooves 542 are formed on the inner wall of the short tube 541. A slider 543 is slidably arranged inside each of the two grooves 542. A block 544 is fixedly arranged between the two sliders 543. A confluence cavity 545 is formed in the middle of the end of the block 544 near the branch liquid chamber 52. Several spray holes 546 are evenly formed around the side wall of the confluence cavity 545. The side wall of the slider 543 is fixedly connected to the side wall of the groove 542 by a first spring 547. A semi-circular mesh cover 548 is fixedly arranged at the end of the short tube 541 away from the dividing vertical plate 51. The suction mechanism 6 includes a receiving box 61, which is fixedly connected to the front end of the processing box 1. The inner cavity of container 61 is equipped with a suction assembly 62. An external gear ring 63 is rotatably mounted at the rear end of the inner cavity of container 61. Several first semicircular blocks 64 are evenly fixed around the inner wall of the external gear ring 63. A short shaft 65 is rotatably mounted between the front and rear walls of the inner cavity of container 61. The front end of the short shaft 65 is fixedly connected to the output end of the servo motor 10. A gear 66 is fixedly sleeved on the outside of the short shaft 65. The left side of the gear 66 meshes with the right side of the external gear ring 63. The suction assembly 62 includes a square block 621, which is fixedly connected to the rear wall of the inner cavity of container 61. A liquid-filling chamber 622 is opened on the left side of the square block 621, and a gas-filling chamber 623 is opened on the right side of the square block 621. T-shaped pistons 624 are slidably mounted inside both the liquid-filling chamber 622 and the gas-filling chamber 623.Two T-shaped pistons 624, with their ends slidably extending through the outer side of the square block 621, are fixedly mounted with a second semicircular block 625. A second spring 626 is fitted around the outside of the T-shaped pistons 624, and the second spring 626 is fixedly connected between the outer wall of the square block 621 and the second semicircular block 625. The bottom right side of the liquid chamber 622 is fixedly connected to the front wall of the processing tank 1 via a liquid extraction pipe 627. The bottom left side of the gas chamber 623 is fixedly connected to a gas extraction pipe 628, the front end of which is fixedly inserted through the front wall of the receiving box 61. A first one-way valve 629 is fixedly mounted on the upper part of both the liquid extraction pipe 627 and the gas extraction pipe 628. The front right side of the liquid chamber 622 is fixedly connected to a drain pipe 62. 10. The top of the drain pipe 6210 is fixedly connected to a horizontal infusion pipe 6211. The rear end of the horizontal infusion pipe 6211 is uniformly fixedly connected to several infusion branch pipes 6212. Each infusion branch pipe 6212 is connected to a corresponding liquid passage chamber 32. The left side of the front end of the gas chamber 623 is fixedly connected to an exhaust pipe 6213. The top of the exhaust pipe 6213 is fixedly connected to a horizontal gas infusion pipe 6214. The rear end of the horizontal gas infusion pipe 6214 is uniformly fixedly connected to several gas infusion branch pipes 6215. Each gas infusion branch pipe 6215 is connected to a corresponding venting chamber 34. A second one-way valve 6216 is fixedly installed at the bottom of both the drain pipe 6210 and the exhaust pipe 6213. Each epitaxial silicon wafer limiting mechanism 7 includes several bumps 71. Several protrusions 71 are uniformly fixedly connected to the inner wall of the processing box 1. A clamping plate assembly 72 is rotatably arranged between adjacent protrusions 71. Each clamping plate assembly 72 has a rack assembly 73 on its exterior. The clamping plate assembly 72 includes a bidirectional lead screw 721, which is rotatably connected between two protrusions 71. A gear disc 722 is fixedly sleeved in the middle of the bidirectional lead screw 721. Opposite-direction threads are formed on the exterior of the bidirectional lead screw 721 and on both sides of the gear disc 722. Two collars 723, located on both sides of the gear disc 722, are sleeved on the external threads of the bidirectional lead screw 721. Connecting rods 724 are fixedly arranged at the upper and lower ends of the collars 723. The end of the connecting rod 724 furthest from the inner wall of the processing box 1 is fixedly... A clamping plate 725 is provided, with several through holes evenly distributed on its surface. A limiting rod 726 is fixedly installed at one end of a collar 723 near the inner wall of the processing box 1. The limiting rod 726 is slidably connected in the corresponding transverse groove 9. A rack assembly 73 includes a limiting block 731, which is slidably connected in the corresponding vertical groove 8. A rack 732 is fixedly installed at one end of the limiting block 731 near the clamping plate assembly 72. The side of the rack 732 away from the limiting block 731 meshes with a gear plate 722. An L-shaped baffle 733 is fixedly installed at the top of the rack 732. The bottom of the limiting block 731 is fixedly connected to the bottom of the vertical groove 8 by a third spring 734. A base plate 735 is fixedly installed at the bottom of the rack 732.

[0059] Through the cooperation between the short pipe 541, the plug 544, the nozzle 546, and the semi-circular mesh cover 548, when the suction mechanism 6 does not supply hydrofluoric acid solution to the disturbance plate mechanism 5, under the elastic action of the first spring 547, the plug 544 is completely located inside the short pipe 541, the nozzle 546 is blocked, and the hydrofluoric acid solution in the treatment tank 1 will not directly enter the short pipe 541. The semi-circular mesh cover 548 can prevent external impurities from clogging the nozzle 546. Similarly, when the suction mechanism 6 does not supply gas to the disturbance plate mechanism 5, the hydrofluoric acid solution in the treatment tank 1 will not enter the gas outlet assembly 55, ensuring that the disturbance plate mechanism 5 can normally discharge liquid and gas. Through the interaction between the suction assembly 62, the external gear ring 63, the first semi-circular block 64, and the gear 66 With their coordinated operation, a single servo motor 10 can drive the mechanism to simultaneously pump hydrofluoric acid solution and gas, eliminating the need for multiple pumps, thus saving energy and reducing production costs. Through the cooperation of the bidirectional lead screw 721, gear disc 722, clamping plate 725, rack 732, and base plate 735, the weight of the epitaxial silicon wafer itself can be used to push the rack 732 downward as it presses down on the base plate 735. This causes the gear disc 722 and bidirectional lead screw 721 to rotate. The rotation of the bidirectional lead screw 721 then brings the two collars 723 closer together, i.e., the clamping plates 725 on the left and right sides closer together, achieving automatic clamping and limiting of the epitaxial silicon wafer for rapid entry into the acid washing stage. This convenient operation improves pretreatment efficiency.

[0060] This invention also provides a pretreatment process for epitaxial silicon wafers with high passivation layer uniformity, employing an epitaxial silicon wafer pretreatment system with high passivation layer uniformity. The specific method includes the following steps:

[0061] Step 1: Place several epitaxial silicon wafers from left to right between two adjacent clamping plate assemblies 72. Utilize the weight of the epitaxial silicon wafers to push the rack 732 downwards while pressing down on the base plate 735, thereby causing the gear plate 722 and the bidirectional lead screw 721 to rotate. The rotation of the bidirectional lead screw 721 causes the two collars 723 to move closer to each other, that is, the clamping plates 725 on the left and right sides to move closer to each other, automatically clamping and limiting the epitaxial silicon wafers. At this time, the epitaxial silicon wafers are immersed in the hydrofluoric acid solution in the processing box 1. Then, start the servo motor 10 to drive the gear 66, the external gear ring 63, and the first semicircular block 64 to rotate. During the rotation of the first semicircular block 64, it cooperates with the second spring 626 to make the second semicircular block 625 and the T-shaped piston 624 reciprocate in the left and right directions.

[0062] Step 2: During the reciprocating motion in the left and right directions, using negative pressure, the hydrofluoric acid solution at the bottom of the inner cavity of the treatment tank 1 is first drawn into the liquid placement chamber 622 through the liquid extraction pipe 627. External gas is then drawn into the gas placement chamber 623 through the air extraction pipe 628. The solution then passes through the drain pipe 6210 and the horizontal infusion pipe 6211, and is pushed through each infusion branch pipe 6212 to the liquid passage chamber 32, the L-shaped liquid outlet 33, and the branch liquid chamber 52. Finally, the solution is pushed through each... The liquid outlet assembly 54 sprays the liquid back into the processing chamber 1, impacting the surface of the adjacent epitaxial silicon wafer. Simultaneously, the gas is pushed through the exhaust pipe 6213 and the horizontal gas supply pipe 6214, and then through the various gas supply branch pipes 6215 into the ventilation chamber 34, the L-shaped gas outlet 35, and the branch gas chamber 53. Finally, the gas is blown into the hydrofluoric acid solution in the processing chamber 1 through the various gas outlet assemblies 55. The circulating hydrofluoric acid solution and the introduced gas work together to make the hydrofluoric acid contact the surface of the epitaxial silicon wafer more evenly. The process efficiently removes oxides and impurities from the surface of the epitaxial silicon wafer, ensuring its flatness and uniformity. Specifically, when the suction mechanism 6 is not supplying hydrofluoric acid solution into the short tube 541, the block 544 is completely positioned within the short tube 541 under the elastic action of the first spring 547, blocking the nozzle 546. This prevents the hydrofluoric acid solution in the processing tank 1 from directly entering the short tube 541 through the nozzle 546. Similarly, when the suction mechanism 6 is not supplying gas into the outlet assembly 55... The hydrofluoric acid solution in the treatment tank 1 will not enter the gas outlet assembly 55. Only when the suction mechanism 6 delivers the hydrofluoric acid solution into the short pipe 541, the block 544 is pushed away from the short pipe 541 under the pressure of the liquid, so that the nozzle 546 is exposed. The hydrofluoric acid solution in the short pipe 541 can then be ejected through the confluence chamber 545 and each nozzle 546. The principle of the gas outlet assembly 55 blowing out gas is the same as the principle of the liquid outlet assembly 54 spraying out liquid.

[0063] Step 3: As the hydrofluoric acid solution flows downward, internal impurities are intercepted by the filter screen 11. The filtered hydrofluoric acid solution enters the suction assembly 62 and circulates up and down to complete the acid washing process of the epitaxial silicon wafer. After the hydrofluoric acid solution in the processing tank 1 is discharged through the discharge pipe 13, the sealing cover 12 is opened to clean out the impurities intercepted on the filter screen 11. Then, the sealing cover 12 is returned to its original position.

[0064] It should be noted that, in this document, relational terms such as "first" and "second" are used only to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such process, method, article, or apparatus.

[0065] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A pretreatment system for epitaxial silicon wafers with high passivation layer uniformity, characterized in that, include: A processing box for holding hydrofluoric acid solution. A support is fixedly installed at the bottom of the processing box. A partition mechanism is fixedly installed between the side walls in the middle of the inner cavity of the processing box. Several guide frames are evenly fixed through the bottom of the partition mechanism from left to right. If the disturbance plate mechanism is used to spray hydrofluoric acid solution and blow out gas, several disturbance plate mechanisms are uniformly fixedly connected to the top of the partition mechanism. A suction mechanism for suctioning hydrofluoric acid solution and gas is provided at the front end of the processing tank. Two epitaxial silicon wafer limiting mechanisms are used to clamp epitaxial silicon wafers of different thicknesses. One epitaxial silicon wafer limiting mechanism is set on the front wall of the inner cavity of the processing box, and the other epitaxial silicon wafer limiting mechanism is set on the rear wall of the inner cavity of the processing box. Several vertical grooves are evenly opened from left to right on the front and rear walls of the inner cavity of the processing box. Horizontal grooves are opened on both sides of each vertical groove on the front and rear walls of the inner cavity of the processing box. A servo motor is fixedly installed at the front end of the suction mechanism. Two filter screens located below the guide frame are fixedly installed between the side walls of the inner cavity of the processing box. A sealing cover is installed on the left side of the processing box above each filter screen. A discharge pipe is fixedly installed at the bottom left side of the processing box. A valve is fixedly installed on the right side of the discharge pipe. The partition mechanism includes a partition. The upper front end of the partition has several liquid passage chambers evenly distributed from left to right. The top of the partition, located directly below each disturbance plate mechanism, has several L-shaped liquid outlet holes distributed from front to back. The L-shaped liquid outlet holes in the same vertical section are connected to adjacent liquid passage chambers. The lower front end of the partition has several air passage chambers evenly distributed from left to right. The top of the partition, located directly below each disturbance plate mechanism, has several L-shaped air outlet holes distributed from front to back. The L-shaped air outlet holes in the same vertical section are connected to adjacent air passage chambers. Each of the aforementioned disturbance plate mechanisms includes a partition vertical plate, the bottom of which is fixedly connected to the top of a partition. The interior of the partition vertical plate is evenly provided with several branch liquid chambers from front to back, and the interior of the partition vertical plate is also evenly provided with several branch air chambers from front to back. These branch liquid chambers and branch air chambers are interleaved. Each branch liquid chamber is connected to a corresponding L-shaped liquid outlet, and each branch air chamber is connected to a corresponding L-shaped air outlet. Several liquid outlet assemblies are fixedly connected to the side of each branch liquid chamber near the guide frame from top to bottom. Several air outlet assemblies are fixedly connected to the side of each branch air chamber near the guide frame from top to bottom. The air outlet assemblies are formed by proportionally reducing the size of the liquid outlet assemblies.

2. The epitaxial silicon wafer pretreatment system with high passivation layer uniformity according to claim 1, characterized in that: The liquid outlet assembly includes a short tube with two grooves on its inner wall. A slider is slidably disposed inside each groove, and a block is fixedly disposed between the two sliders. A confluence cavity is formed in the middle of the end of the block near the branch liquid chamber. Several spray holes are evenly distributed around the side wall of the confluence cavity. The side wall of the slider is fixedly connected to the side wall of the groove by a first spring. A semi-circular mesh cover is fixedly disposed at the end of the short tube away from the dividing vertical plate.

3. The epitaxial silicon wafer pretreatment system with high passivation layer uniformity according to claim 1, characterized in that: The suction mechanism includes a receiving box, which is fixedly connected to the front end of the processing box. The inner cavity of the receiving box is provided with a suction component. An external gear ring is rotatably provided at the rear end of the inner cavity of the receiving box. Several first semicircular blocks are evenly fixedly provided around the inner wall of the external gear ring. A short shaft is rotatably provided between the front and rear walls of the inner cavity of the receiving box. The front end of the short shaft is fixedly connected to the output end of a servo motor. A gear is fixedly sleeved on the outside of the short shaft. The left side of the gear meshes with the right side of the external gear ring.

4. The epitaxial silicon wafer pretreatment system with high passivation layer uniformity according to claim 3, characterized in that: The suction assembly includes a square block, which is fixedly connected to the rear wall of the inner cavity of the receiving box. A liquid-containing chamber is formed on the left side of the square block, and a gas-containing chamber is formed on the right side. T-shaped pistons are slidably disposed inside both the liquid-containing and gas-containing chambers. The ends of the two T-shaped pistons, which are far apart from each other, slide through to the outside of the square block and are fixedly disposed on a second semicircular block. A second spring is sleeved on the outside of each T-shaped piston, and the second spring is fixedly connected between the outer wall of the square block and the second semicircular block. The bottom right side of the liquid-containing chamber is fixedly connected to the front wall of the processing box via a liquid suction pipe. The bottom left side of the gas-containing chamber is fixedly connected to an air suction pipe. The front end of the tube is fixedly connected through the front wall of the receiving box. A first one-way valve is fixedly installed at the upper part of both the liquid extraction tube and the air extraction tube. A drain tube is fixedly connected to the right side of the front end of the liquid placement chamber. A horizontal infusion tube is fixedly connected to the top of the drain tube. Several infusion branch tubes are evenly fixedly connected to the rear end of the horizontal infusion tube. Each infusion branch tube is connected to a corresponding liquid passage chamber. An exhaust tube is fixedly connected to the left side of the front end of the air placement chamber. A horizontal air supply tube is fixedly connected to the top of the exhaust tube. Several horizontal air supply branch tubes are evenly fixedly connected to the rear end of the horizontal air supply tube. Each air supply branch tube is connected to a corresponding air passage chamber. A second one-way valve is fixedly installed at the bottom of both the drain tube and the exhaust tube.

5. The epitaxial silicon wafer pretreatment system with high passivation layer uniformity according to claim 4, characterized in that: Each of the epitaxial silicon wafer limiting mechanisms includes several bumps, which are uniformly and fixedly connected to the inner wall of the processing box. A clamping plate assembly is rotatably arranged between adjacent bumps, and a rack and pinion assembly is provided on the outside of each clamping plate assembly.

6. The epitaxial silicon wafer pretreatment system with high passivation layer uniformity according to claim 5, characterized in that: The clamping plate assembly includes a bidirectional lead screw rotatably connected between two protrusions. A gear plate is fixedly sleeved in the middle of the bidirectional lead screw. Opposite threads are formed on the outer side of the bidirectional lead screw and on both sides of the gear plate. Two collars are respectively sleeved on the outer threads of the bidirectional lead screw on both sides of the gear plate. Connecting rods are fixedly provided at the upper and lower ends of the collars. A clamping plate is fixedly provided at the end of the connecting rod away from the inner wall of the processing box. Several through holes are evenly formed on the surface of the clamping plate. A limiting rod is fixedly provided at the end of the collar near the inner wall of the processing box. The limiting rod is slidably connected in the corresponding horizontal groove. The rack assembly includes a limiting block slidably connected in the corresponding vertical groove. A rack is fixedly provided at the end of the limiting block near the clamping plate assembly. The side of the rack away from the limiting block meshes with the gear plate. An L-shaped baffle is fixedly provided at the top of the rack. The bottom of the limiting block is fixedly connected to the bottom of the vertical groove by a third spring. A base plate is fixedly provided at the bottom of the rack.

7. A method for pre-processing epitaxial silicon wafers with high passivation layer uniformity, characterized in that: The epitaxial silicon wafer pretreatment system with high passivation layer uniformity as described in claim 5 includes the following steps: Step 1: Place several epitaxial silicon wafers from left to right between two adjacent clamping plate assemblies. Under the action of the weight of the epitaxial silicon wafers, the rack assembly is pressed down, and the clamping plate assembly completes the clamping and limiting of the epitaxial silicon wafers. At the same time, the epitaxial silicon wafers are immersed in hydrofluoric acid solution. Then, the servo motor is started to drive the gear, external gear ring and the first semicircular block to rotate. During the rotation of the first semicircular block, it cooperates with the second spring to make the second semicircular block and the T-shaped piston reciprocate in the left and right directions. Step 2: During the process, using negative pressure, the hydrofluoric acid solution at the bottom of the processing chamber is first drawn into the liquid placement chamber through the liquid extraction pipe, and external gas is drawn into the gas placement chamber through the gas extraction pipe. Then, the hydrofluoric acid solution is pushed into the disturbance plate mechanism through each liquid delivery branch pipe and sprayed into the processing chamber again to impact the surface of the epitaxial silicon wafer. The gas is pushed into the disturbance plate mechanism through each gas delivery branch pipe. Then, gas is introduced into the hydrofluoric acid solution in the processing chamber to make the hydrofluoric acid contact the surface of the epitaxial silicon wafer more evenly, effectively remove oxides and impurities from the surface of the epitaxial silicon wafer, and ensure the flatness and uniformity of the surface of the epitaxial silicon wafer. Step 3: As the hydrofluoric acid solution flows downward, internal impurities are intercepted by the filter screen. The filtered hydrofluoric acid solution enters the suction assembly and circulates up and down to complete the acid washing of the epitaxial silicon wafer.

8. The method for pre-processing an epitaxial silicon wafer with high passivation layer uniformity according to claim 7, characterized in that: Each of the clamping plate assemblies is located between two adjacent disturbance plate mechanisms.

Images