A fixing device for spin-drying GaAs wafer

Abstract

The application relates to a fixing device for GaAs wafer spin-drying, belonging to the technical field of wafers, which comprises a spin-drying barrel, a table top and an outer ring arranged in the spin-drying barrel, the table top is horizontally arranged and rotates relative to the spin-drying barrel, the table top is circular, the table top is coincident with the center of the outer ring, and the outer ring is slidingly arranged along the vertical direction; when the top surface of the outer ring is flush with the top surface of the table top, the outer ring rotates synchronously with the table top; the table top and the outer ring are both hollow and are provided with air holes on the top surfaces; the spin-drying barrel is provided with a first vacuum pump and a second vacuum pump, the first vacuum pump is communicated with the inside of the table top, and the second vacuum pump is communicated with the inside of the outer ring; the application has the effects of applying safe negative pressure to the wafer, ensuring the fixation of the wafer and reducing the damage to the wafer.

Description

Technical Field

[0001] This application relates to the technical field of wafers, and in particular to a fixing device for drying GaAs wafers. Background Technology

[0002] In the semiconductor industry, wafers are called wafers. Wafers are the core basic material of the semiconductor industry. Simply put, they are a thin slice of semiconductor crystal that has been highly purified and has a smooth surface. They are the "foundation" for manufacturing chips (integrated circuits).

[0003] GaAs wafers are typically secured during spin-drying using methods such as vacuum adsorption and mechanical clamping. Mechanical clamping can damage the wafer edges. Vacuum chucks, with their densely packed micro-channels connected to an external vacuum pump system, are used to fix the wafer. When the vacuum pump is activated, it removes the air between the chuck and the wafer, creating a vacuum zone beneath the wafer. The external atmospheric pressure then firmly presses the wafer against the chuck surface, achieving stable fixation. This method avoids direct contact with the wafer surface, effectively preventing mechanical damage and contamination.

[0004] For brittle and easily damaged wafers such as GaAs, vacuum adsorption applies the same pressure to every region of the wafer. During the spin-drying process, as the wafer rotates with the platform, the linear velocity at the edge is much higher than that at the center. If the applied negative pressure is uniform, the edge region of the wafer may experience slight warping or slippage due to insufficient adsorption force. If the negative pressure is increased, the center of the wafer is less affected by centrifugal force, but this results in excessively high negative pressure, which can easily cause microcracks in the center region due to excessive pressure. Utility Model Content

[0005] In order to apply safe negative pressure to the wafer, ensure the wafer is fixed, and reduce damage to the wafer, this application provides a fixing device for drying GaAs wafers.

[0006] The fixing device for drying GaAs wafers provided in this application adopts the following technical solution:

[0007] A fixing device for spin-drying GaAs wafers includes a spin-drying drum, a platform and an outer ring disposed inside the drum. The platform is horizontally positioned and rotates relative to the spin-drying drum. The platform is circular, and its center coincides with that of the outer ring. The outer ring slides vertically. When the top surface of the outer ring is flush with the top surface of the platform, the outer ring rotates synchronously with the platform. Both the platform and the outer ring are hollow inside, and each has air holes on its top surface. A first vacuum pump and a second vacuum pump are disposed inside the spin-drying drum. The first vacuum pump is connected to the interior of the platform, and the second vacuum pump is connected to the interior of the outer ring.

[0008] By adopting the above technical solution, the mesa and outer ring are respectively connected to independent first and second vacuum pumps, allowing for individual adjustment of their negative pressure intensity. The mesa corresponds to the central region of the wafer, while the outer ring corresponds to the edge region. Based on the difference in centrifugal force (edge ​​> center), the negative pressure of the outer ring can be made greater than that of the mesa. This ensures sufficient adsorption force in the edge region to resist centrifugal force while preventing excessively high negative pressure in the central region from causing microcracks, thus achieving safe fixation of the GaAs wafer and reducing damage. Simultaneously, the outer ring can slide vertically, facilitating adjustment of its relative position to the mesa according to the wafer size (e.g., small wafers can be adsorbed using only the mesa, while large wafers require auxiliary fixation with the outer ring), improving device compatibility.

[0009] Optionally, a cylinder is fixed inside the spin dryer. The cylinder is arranged vertically, and the outer ring is composed of a ring shell and a ring. The ring is rotatable relative to the ring shell, and the piston end of the cylinder is fixedly connected to the ring.

[0010] By adopting the above technical solution, the cylinder drives the outer ring to rise and fall vertically, realizing the switching of the height position of the outer ring and the platform; the ring rotates relative to the ring shell, ensuring that when the top surface of the outer ring is flush with the platform, the ring shell can rotate synchronously with the platform (meeting the spin-drying requirements), while the ring and cylinder are fixed (ensuring the stability of the lifting structure). This design achieves both lifting and adjusting of the outer ring without affecting its rotation function, and is compact and reliable in linkage.

[0011] Optionally, a guide rod is provided inside the spin dryer. The guide rod is arranged in a vertical direction, with its bottom end fixedly connected to the spin dryer and its top end penetrating through the ring and extending into the inner part of the outer ring.

[0012] By adopting the above technical solution, the guide rod guides the lifting and lowering of the ring, preventing the outer ring from shifting or tilting circumferentially when moving vertically, ensuring that the outer ring always coincides with the center of the platform, guaranteeing the precise engagement of the subsequent protrusions and slots, and improving structural stability.

[0013] Optionally, an inner ring is provided inside the outer ring. The inner ring is horizontally positioned, and its bottom surface is fixedly connected to the top of the guide rod. A sealing head is fixed on the top surface of the inner ring. The sealing head is located directly below the air hole on the outer ring, and the number of sealing heads corresponds to the number of air holes on the outer ring. When the top surface of the outer ring is flush with the top surface of the platform, the bottom surface of the inner ring abuts against the inner wall of the bottom of the outer ring. When the sealing head is inserted into the air hole of the outer ring, the outer ring and the platform are misaligned.

[0014] By adopting the above technical solution, when the outer ring descends (misaligns with the mesa), the sealing head is inserted into the vent of the outer ring, blocking the negative pressure path of the outer ring and preventing impurities from entering the vent when not in operation. This is because the wafer surface needs to be rinsed during the spin-drying process, preventing wastewater from entering the outer ring through the vent. When the outer ring rises to be flush with the mesa, the inner ring abuts against the bottom of the outer ring, the sealing head disengages from the vent, and the inner ring simultaneously supports the internal space of the ring shell, ensuring stable negative pressure in the outer ring. This structure achieves automatic opening and closing of the outer ring vent, reducing manual operation and improving safety.

[0015] Optionally, the ring shell is provided with a slot, and a protrusion is fixed on the circumferential side wall of the platform. When the top surface of the outer ring is flush with the top surface of the platform, the protrusion is inserted into the corresponding slot.

[0016] By adopting the above technical solution, when the outer ring is flush with the platform, the protrusion is fitted into the slot, so that the two are relatively fixed in the circumferential direction, ensuring that the platform and the outer ring rotate synchronously during spin drying, avoiding friction damage to the wafer edge due to relative sliding, and ensuring that the adsorption force is evenly applied to the wafer.

[0017] Optionally, a partition is fixed inside the spin-drying drum to separate the internal space of the drum vertically, and the cylinder, the first vacuum pump and the second vacuum pump are both located below the partition.

[0018] By adopting the above technical solution, the partition divides the interior of the spin dryer into upper and lower spaces. The lower space accommodates driving components such as cylinders and vacuum pumps, while the upper space is the wafer processing area. This effectively isolates wastewater from electrical components, reduces the corrosion of the equipment by liquids, and extends its service life.

[0019] Optionally, the partition is convex in the middle, and a drain pipe is provided on the spin-drying drum. The connection between the drain pipe and the inside of the spin-drying drum is located above and close to the edge of the partition.

[0020] By adopting the above technical solution, the raised baffle guides the wastewater to flow towards the edge. Combined with the drain pipe near the edge, the wastewater generated during the spin-drying process can be quickly discharged, reducing the residue of wastewater in the treatment area and lowering the risk of secondary contamination of the wafer.

[0021] Optionally, both the platform and the top of the outer ring are fixed with rubber rings, the number of rubber rings corresponding to the number of air holes, and the rubber rings are fixed at the edge of the air holes to encompass the air holes.

[0022] By adopting the above technical solution, the rubber ring covering the edge of the pores can enhance the sealing between the wafer and the mesa and the outer ring, and reduce negative pressure leakage. At the same time, the rubber material is elastic and can buffer the pressure during adsorption, avoiding scratches or microcracks caused by direct contact between the wafer surface and the hard mesa, and further protecting the brittle GaAs wafer.

[0023] In summary, this application includes at least one of the following beneficial technical effects:

[0024] 1. By controlling the independent negative pressure of the mesa and the outer ring, differentiated adsorption is achieved in the center and edge regions of the wafer, balancing fixation stability and damage risk, and adapting to the brittle characteristics of GaAs wafers;

[0025] 2. The outer ring can be raised and lowered and rotates in conjunction with the table surface. Combined with the sealing head, rubber ring and other structures, it takes into account the compatibility of wafers of different sizes, adsorption and sealing performance and equipment cleanliness, thereby improving process adaptability.

[0026] 3. The design of the baffle and drainage pipe optimizes the sewage discharge path, reduces secondary pollution, and isolates the drive components from the treatment area, extending the service life of the equipment. Attached Figure Description

[0027] Figure 1 This is a structural schematic diagram of an embodiment of this application;

[0028] Figure 2 This is a top view of an embodiment of this application;

[0029] Figure 3 yes Figure 2 A sectional view of section AA;

[0030] Figure 4 yes Figure 2 A sectional view of section BB.

[0031] In the diagram, 1. Spin-drying drum; 11. First vacuum pump; 12. Second vacuum pump; 13. Cylinder; 14. Guide rod; 15. Partition plate; 2. Platform; 21. Protrusion; 3. Outer ring; 31. Ring shell; 311. Slot; 32. Ring; 4. Air hole; 5. Inner ring; 51. Sealing head; 6. Rubber ring. Detailed Implementation

[0032] The following is in conjunction with the appendix Figures 1-4 This application will be described in further detail.

[0033] This application discloses a fixing device for drying GaAs wafers.

[0034] refer to Figure 1 and Figure 2 A fixing device for drying GaAs wafers includes a drying drum 1, inside which a circular platform 2 is horizontally arranged. The platform 2 is driven by a drive component, which in this embodiment is a motor. The platform 2 rotates relative to the drying drum 1 around its own axis. An outer ring 3 is fitted around the outer side of the platform 2. The outer ring 3 is concentric with the platform 2 and can slide vertically to adjust the relative height between its top surface and the top surface of the platform 2.

[0035] refer to Figure 2 , Figure 3 and Figure 4 Both the platform 2 and the outer ring 3 are hollow structures, and multiple air holes 4 are opened on the top surface of both. The air holes 4 are evenly distributed on the top surface of the platform 2 and the outer ring 3, and the line connecting the air holes 4 on the outer ring 3 is circular. A first vacuum pump 11 and a second vacuum pump 12 are fixed inside the spin dryer 1. The first vacuum pump 11 is connected to the internal cavity of the platform 2 through a pipe, and the second vacuum pump 12 is connected to the internal cavity of the outer ring 3 through a pipe, thereby realizing independent negative pressure control of the platform 2 and the outer ring 3.

[0036] refer to Figure 2 , Figure 3 and Figure 4 A cylinder 13, arranged vertically, is fixed inside the spin-drying drum 1. The bottom end of the cylinder 13 is fixedly connected to the inner wall of the spin-drying drum 1. The outer ring 3 consists of a ring shell 31 and a ring 32. The ring 32 is located at the bottom of the ring shell 31 and is rotatably arranged relative to the ring shell 31. The top end of the piston of the cylinder 13 is fixedly connected to the bottom surface of the ring 32. The extension and retraction of the cylinder 13 can drive the outer ring 3 to rise and fall as a whole. The second vacuum pump 12 is connected to the internal cavity of the outer ring 3 through a pipe and is located on the ring 32. When the outer ring 3 rises to the point where its top surface is flush with the top surface of the platform 2, the protrusion 21 fixed on the circumferential side wall of the platform 2 is precisely inserted into the slot 311 opened on the inner side of the ring shell 31, so that the ring shell 31 rotates synchronously with the platform 2. When the outer ring 3 descends, the protrusion 21 disengages from the slot 311, and the outer ring 3 stops rotating. The method by which the first vacuum pump 11 is connected to the internal cavity of the platform 2 through a pipe is a conventional method and does not affect the rotation of the platform 2, so it will not be described in detail. In this embodiment, the method by which the second vacuum pump 12 is connected to the internal cavity of the outer ring 3 through a pipe can be referred to.

[0037] refer to Figure 2 , Figure 3 and Figure 4 Inside the spin-drying drum 1, two vertically oriented guide rods 14 are fixedly installed. The bottom end of the guide rod 14 is fixedly connected to the inner wall of the spin-drying drum 1, and the top end passes through the ring 32 and extends into the outer ring 3. Inside the outer ring 3, there is a horizontal inner ring 5. The bottom surface of the inner ring 5 is fixedly connected to the top end of the guide rod 14. Multiple sealing heads 51 are fixedly installed on the top surface of the inner ring 5. The number of sealing heads 51 is the same as the number of air holes 4 on the outer ring 3, and each sealing head 51 is located directly below the corresponding air hole 4. When the outer ring 3 descends to a position where it is misaligned with the platform 2 (the top surface is lower than the top surface of the platform 2), the sealing head 51 is inserted into the air hole 4 of the outer ring 3, blocking the communication between the air hole 4 and the internal cavity of the outer ring 3. When the outer ring 3 rises until the top surface is flush with the platform 2, the bottom surface of the inner ring 5 abuts against the bottom inner wall of the ring shell 31, the sealing head 51 disengages from the air hole 4, and the air hole 4 resumes communication.

[0038] refer to Figure 2Both the mesa 2 and the outer ring 3 have rubber rings 6 fixed to their top surfaces. The number of rubber rings 6 corresponds one-to-one with the vents 4, and each rubber ring 6 is arranged around the edge of the corresponding vent 4. The top surface of the rubber ring 6 is slightly higher than the top surface of the mesa 2 and the outer ring 3. When the wafer is placed on the mesa 2 and the outer ring 3, the rubber rings 6 can enhance the sealing between the wafer and the mesa 2 and the outer ring 3, while also buffering the adsorption pressure through their own elasticity.

[0039] refer to Figure 2 , Figure 3 and Figure 4 A horizontal partition 15 is fixed inside the spin dryer 1, dividing the interior of the spin dryer 1 into upper and lower spaces. The cylinder 13, the first vacuum pump 11, the second vacuum pump 12, and the motor that drives the rotating platform 2 are all located below the partition 15, while the platform 2 and the outer ring 3 are located above the partition 15. The partition 15 has a structure with a raised center and inclined edges. A drain pipe is connected to the side wall of the spin dryer 1. The connection between the drain pipe and the interior of the spin dryer 1 is located above and close to the edge of the partition 15, so that wastewater can flow into the drain pipe and be discharged along the inclined edge of the partition 15.

[0040] The implementation principle of this application embodiment is as follows: During use, the height of the outer ring 3 is adjusted by the cylinder 13 according to the wafer size. For small wafers, it is only necessary to place them on the platform 2. At this time, the outer ring 3 is controlled to descend, the sealing head 51 is inserted into the air hole 4 of the outer ring 3, and the first vacuum pump 11 is started to evacuate the platform 2. The wafer is fixed by adsorption through the negative pressure of the platform 2. For large wafers, the cylinder 13 is controlled to drive the outer ring 3 to rise, so that the top surface of the outer ring 3 is flush with the top surface of the platform 2, the protrusion 21 is embedded in the slot 311, the sealing head 51 is disengaged from the air hole 4, the wafer is placed on the platform 2 and the outer ring 3, and the first vacuum pump 11 and the second vacuum pump 12 are started respectively. By adjusting the negative pressure intensity of the two (the negative pressure of the outer ring 3 is greater than that of the platform 2), the edge of the wafer obtains a stronger adsorption force to resist centrifugal force, while the central area maintains a moderate negative pressure to avoid damage.

[0041] During the spin-drying process, the platform 2 drives the outer ring 3 and the wafer to rotate synchronously. Wastewater is ejected under centrifugal force, flowing along the inclined surface of the partition 15 to the edge and being discharged through the drain pipe. The rubber ring 6 enhances the adsorption seal, and the partition 15 isolates the wastewater from the driving components below, reducing equipment corrosion. After spin-drying, the vacuum pump is turned off, the cylinder 13 drives the outer ring 3 to descend, and the sealing head 51 seals the vent 4, allowing the wafer to be removed.

[0042] The embodiments described in this specific implementation are preferred embodiments of this application and are not intended to limit the scope of protection of this application. Therefore, all equivalent changes made in accordance with the structure, shape and principle of this application should be covered within the scope of protection of this application.

Claims

1. A fixing device for drying GaAs wafers, comprising a drying drum (1), characterized in that: The spin dryer (1) is provided with a table (2) and an outer ring (3). The table (2) is horizontal and rotates relative to the spin dryer (1). The table (2) is circular and the center of the table (2) coincides with the center of the outer ring (3). The outer ring (3) is slidably set in the vertical direction. When the top surface of the outer ring (3) is flush with the top surface of the table (2), the outer ring (3) rotates synchronously with the table (2). Both the table (2) and the outer ring (3) are hollow inside and have air holes (4) on their top surfaces. The spin dryer (1) is provided with a first vacuum pump (11) and a second vacuum pump (12). The first vacuum pump (11) is connected to the inside of the table (2), and the second vacuum pump (12) is connected to the inside of the outer ring (3).

2. The fixing device for drying GaAs wafers according to claim 1, characterized in that: A cylinder (13) is fixed inside the spin dryer (1). The cylinder (13) is arranged in a vertical direction. The outer ring (3) is composed of a ring shell (31) and a ring (32). The ring (32) is rotatably arranged relative to the ring shell (31). The piston end of the cylinder (13) is fixedly connected to the ring (32).

3. The fixing device for drying GaAs wafers according to claim 2, characterized in that: The spin dryer (1) is provided with a guide rod (14), which is set in a vertical direction. The bottom end of the guide rod (14) is fixedly connected to the spin dryer (1), and the top end of the guide rod (14) passes through the ring (32) and extends into the inner part of the outer ring (3).

4. The fixing device for drying GaAs wafers according to claim 3, characterized in that: The outer ring (3) is provided with an inner ring (5) inside. The inner ring (5) is horizontally set. The bottom surface of the inner ring (5) is fixedly connected to the top of the guide rod (14). The top surface of the inner ring (5) is fixed with a sealing head (51). The sealing head (51) is located directly below the air hole (4) on the outer ring (3). The number of sealing heads (51) corresponds to the number of air holes (4) on the outer ring (3). When the top surface of the outer ring (3) is flush with the top surface of the platform (2), the bottom surface of the inner ring (5) abuts against the bottom inner wall of the outer ring (3). When the sealing head (51) is inserted into the air hole (4) of the outer ring (3), the outer ring (3) and the platform (2) are misaligned.

5. The fixing device for drying GaAs wafers according to claim 2, characterized in that: The ring shell (31) has a slot (311) and a protrusion (21) is fixed on the circumferential side wall of the platform (2). When the top surface of the outer ring (3) is flush with the top surface of the platform (2), the protrusion (21) is inserted into the corresponding slot (311).

6. The fixing device for drying GaAs wafers according to claim 2, characterized in that: The spin dryer (1) is fixed with a partition (15) for dividing the internal space of the spin dryer (1) vertically. The cylinder (13), the first vacuum pump (11) and the second vacuum pump (12) are all located below the partition (15).

7. The fixing device for drying GaAs wafers according to claim 6, characterized in that: The partition (15) is raised in the middle, and a drain pipe is provided on the spin dryer (1). The connection between the drain pipe and the interior of the spin dryer (1) is located above the edge of the partition (15) and close to the edge of the partition (15).

8. The fixing device for drying GaAs wafers according to claim 1, characterized in that: The top of the platform (2) and the outer ring (3) are both fixed with rubber rings (6). The number of rubber rings (6) corresponds to the number of air holes (4) opened. The rubber rings (6) are fixed at the edge of the air holes (4) to encompass the air holes (4).

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