Wafer polishing apparatus

Abstract

This utility model discloses a wafer polishing apparatus, including a polishing platform, a fixture, and a vacuum pump. The fixture has an adsorption end for adsorbing the workpiece to be processed and an anti-backflow can. The anti-backflow can has a accommodating cavity. The adsorption end is connected to the accommodating cavity of the anti-backflow can through a first adsorption tube section. The vacuum pump is connected to the accommodating cavity of the anti-backflow can through a second adsorption tube section. The anti-backflow can is equipped with a filter element for allowing gas to pass through while trapping liquid. The second adsorption tube section is connected to the filter element. This utility model has an anti-backflow can at the front end of the vacuum pump. The anti-backflow can has a large volume, which can effectively prevent the clogging problem caused by the backflow of polishing liquid. A blower is connected to the first adsorption tube section to promptly blow and clean the first adsorption tube, eliminating residual polishing liquid in the tube. This can prevent clogging of the tube and vacuum pump, and also clean the inside of the fixture, reducing the risk of tube clogging and the problem of wafer breakage caused by tube clogging, thus improving production efficiency.

Description

Technical Field

[0001] This utility model relates to the field of chip fabrication technology, and in particular to a wafer polishing device. Background Technology

[0002] In the fabrication of GaN laser chips, wafer thinning and polishing is an essential step. The GaN wafer is fixed to a 4-inch sapphire crystal using a wax-attach method. After grinding, polishing is performed. The ground GaN wafer with sapphire crystal is then vacuum-adsorbed onto the fixture of the polishing device. Under the device's drive, polishing is carried out. During polishing, polishing fluid can easily be drawn into the gap between the fixture's adsorption surface and the sapphire surface. This polishing fluid tends to deposit and crystallize, causing blockages in the vacuum channels and even the vacuum pump. This affects production capacity and can lead to wafer breakage due to insufficient vacuum, thus impacting production quality and efficiency to some extent. Therefore, a wafer polishing device is urgently needed to solve these problems. Utility Model Content

[0003] To address the aforementioned problems, this utility model provides a wafer polishing apparatus, including a polishing platform, a fixture, and a vacuum pump. The fixture is provided with an adsorption end for adsorbing the workpiece to be processed, and also includes an anti-backflow can. The anti-backflow can has a accommodating cavity. The adsorption end is connected to the accommodating cavity of the anti-backflow can through a first adsorption tube section. The vacuum pump is connected to the accommodating cavity of the anti-backflow can through a second adsorption tube section. The anti-backflow can is provided with a filter element for filtering the polishing liquid, and the second adsorption tube section is connected to the filter element.

[0004] Furthermore, the filter element is an activated carbon filter element.

[0005] Furthermore, the anti-backflow can includes a can body and a can lid, the can lid being placed on the can body, and the filter element being detachably mounted on the can lid.

[0006] Furthermore, it also includes a blower, which is connected in parallel to the first adsorption tube section via a purging pipe.

[0007] Furthermore, the connection point between the purging pipe and the first adsorption pipe section is located close to the anti-backflow tank.

[0008] Furthermore, a first valve is provided on the first adsorption tube section, and the first valve is located between the anti-backflow tank and the bypass point.

[0009] Furthermore, the first adsorption tube section is equipped with a sensor for monitoring the liquid.

[0010] Furthermore, a second valve is provided on the purging pipe.

[0011] Furthermore, the anti-backflow tank is equipped with a level gauge.

[0012] Furthermore, the bottom of the anti-backflow tank is provided with a drain outlet.

[0013] By adopting the above technical solution, this utility model has the following beneficial effects compared with the prior art:

[0014] 1) The wafer polishing device provided by this utility model has an anti-backflow tank at the front end of the vacuum pump. The anti-backflow tank is large in volume, which can effectively prevent the clogging problem caused by the backflow of polishing liquid and ensure the normal operation of the vacuum pump.

[0015] 2) The wafer polishing device provided by this utility model has a blower connected to the first adsorption tube section, which can promptly blow and clean the first adsorption tube, eliminate the residual polishing liquid in the tube, prevent the tube and vacuum pump from being blocked, and also clean the inside of the fixture, reduce the risk of tube blockage, reduce the problem of wafer breakage caused by tube blockage, and improve production efficiency. Attached Figure Description

[0016] To more clearly illustrate the technical solutions in the embodiments of this utility model or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this utility model. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0017] Figure 1 This is a schematic diagram of the structure of the wafer polishing device provided by this utility model.

[0018] 1-Polishing platform; 2-Clamping fixture; 3-Vacuum pump; 4-Workpiece to be processed; 5-Anti-backflow tank; 6-Blower; 7-First adsorption tube section; 8-Second adsorption tube section; 9-Purge pipe; 10-Polishing pad; 11-Polishing liquid tank; 12-Filter element; 13-First valve; 14-Second valve. Detailed Implementation

[0019] The technical solutions of the present utility model will be clearly and completely described below with reference to the accompanying drawings of the embodiments. Obviously, the described embodiments are only some embodiments of the present utility model, not all embodiments. Based on the embodiments of the present utility model, all other embodiments obtained by those skilled in the art without creative effort are within the protection scope of the present utility model. In the accompanying drawings, the dimensions and relative dimensions of certain parts may be enlarged for clarity.

[0020] In the description of this utility model, unless otherwise explicitly specified and limited, the terms "connection" and "connected" should be interpreted broadly. For example, they can be fixed connections, detachable connections, or integral connections; they can be mechanical connections or electrical connections; they can be direct connections or indirect connections through an intermediate medium; they can be internal connections between two components or the interaction between two components. For those skilled in the art, the specific meaning of the above terms in this utility model can be understood according to the specific circumstances.

[0021] In the description of this utility model, the terms "upper", "lower", "left", "right", "front", "back", "center", "horizontal", "vertical", "top", "bottom", "inner", and "outer" are based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of description and simplification of operation, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this utility model.

[0022] Furthermore, in the description of this utility model, the terms "first" and "second" are used merely for descriptive distinction and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Additionally, features defined with "first" and "second" may explicitly or implicitly include one or more of that feature.

[0023] As per the instruction manual Figure 1 As shown, this utility model provides a wafer polishing device, including a polishing platform 1, a fixture 2, and a vacuum pump 3. The fixture 2 is provided with an adsorption end for adsorbing the workpiece 4 to be processed. The vacuum pump 3 is connected to the adsorption end. The adsorption end is located directly above the polishing platform 1. It also includes an anti-backflow canister 5. The anti-backflow canister 5 is provided with a accommodating cavity. The adsorption end is connected to the accommodating cavity of the anti-backflow canister 5 through a first adsorption tube section 7. The vacuum pump is connected to the accommodating cavity of the anti-backflow canister 5 through a second adsorption tube section 8. The anti-backflow canister 5 is provided with a filter element 12 for filtering polishing liquid. The second adsorption tube section 8 is connected to the filter element 12.

[0024] In an optimized implementation, the filter element 12 is an activated carbon filter element. This activated carbon filter element can filter polishing liquid and crystals, allowing air to pass through without affecting the adsorption effect of the vacuum pump. An anti-backflow tank 5 is installed between the vacuum pump and the adsorption end of the clamp. The anti-backflow tank 5 has a large volume and can hold a certain amount of liquid. Therefore, when polishing liquid is drawn into the gap between the adsorption end and the sapphire surface, the polishing liquid can be contained within the anti-backflow tank 5, preventing it from entering the vacuum pump 3 and affecting its performance. The anti-backflow tank 5 is equipped with a filter element 12, which allows gas to pass through while trapping liquid, further preventing polishing liquid from entering the vacuum pump 3 and thus preventing the polishing liquid from crystallizing within the vacuum pump 3 and affecting its performance.

[0025] The optimized implementation also includes a blower 6, which is connected in parallel to the first adsorption tube section 7 via a purging pipe 9.

[0026] Specifically, the workpiece 4 to be processed is a wafer, which is attached to sapphire. The sapphire is adsorbed onto the adsorption end of the fixture 2, with the wafer facing the polishing platform 1. The polishing platform 1 rotates to perform the polishing operation. A polishing pad 10 is provided on the polishing platform 1, and the adsorption end is located directly above the polishing pad 10. The polishing pad 10 and the workpiece 4 on the adsorption end move relative to each other. The polishing pad 10 rubs against the wafer to perform the polishing operation. The polishing pad 10 can be set with a suitable roughness as needed. A polishing liquid tank 11 is provided above the polishing platform 1 to store polishing liquid. The polishing liquid tank is connected to a pipe for dripping polishing liquid onto the polishing area.

[0027] In some embodiments, the clamp 2 is disposed on one side of the polishing platform 1, and the adsorption end is elliptical and convexly disposed on the clamp 2 so as to adjust the distance between the adsorption end and the polishing pad 10, which is suitable for different polishing needs.

[0028] Preferably, the polishing platform 1 is connected to a drive unit for rotating it, and the polishing pad 10 rotates under the action of the drive unit, thereby polishing the workpiece. And / or, the fixture 2 is connected to a drive unit for rotating it, causing relative movement between the workpiece and the polishing pad to complete the polishing. When the polishing platform 1 and the fixture 2 are each connected to a drive unit, their rotation directions are opposite.

[0029] Preferably, since the polishing fluid is prone to sedimentation and crystallization, the filter element needs to be cleaned and replaced regularly to prevent the polishing fluid from depositing and crystallizing inside the filter element, affecting its use. The anti-backflow tank 5 includes a tank body and a tank cover. The tank cover is placed on the tank body, and the filter element 12 is detachably mounted on the tank cover. The tank cover can be threaded or hinged to the tank body to allow opening the tank cover for cleaning, maintenance, or replacement of the filter element, ensuring the normal use of the anti-backflow tank.

[0030] In an optimized implementation, the anti-backflow tank 5 has an inlet and an outlet. The first adsorption tube section 7 is connected to the inlet, and the second adsorption tube section 8 is connected to the outlet. The elevation of the outlet is higher than that of the inlet. In this embodiment, the outlet is located on the tank cover, and the inlet is located in the middle or upper part of the anti-backflow tank 5. During use, it must be ensured that the inlet is higher than the highest liquid level inside the anti-backflow tank 5.

[0031] In an optimized implementation, the anti-backflow tank 5 is equipped with a level gauge to monitor the liquid level inside the anti-backflow tank 5 and prevent the liquid level from exceeding the inlet end of the anti-backflow tank 5, thus preventing backflow from the inlet end into the first adsorption tube section 7.

[0032] Preferably, the anti-backflow tank 5 is provided with a drain port, which is located at the bottom of the anti-backflow tank 5. When the level gauge detects that the liquid level in the anti-backflow tank 5 is higher than the set threshold, the drain port is opened to empty the anti-backflow tank 5.

[0033] In an optimized implementation, the connection point between the purging pipe 9 and the first adsorption pipe section 7 is located near the anti-backflow tank 5. The blower 6 can blow air into the purging pipe 9 to clean the first adsorption pipe section 7 and the adsorption end, preventing polishing liquid residue from causing blockage.

[0034] Specifically, the first adsorption tube section 7 is equipped with a sensor for monitoring the liquid. The sensor is located near the anti-backflow tank. The sensor can detect the liquid in the pipe and issue an early warning. After polishing is completed, the blower is turned on to purge and discharge the polishing liquid from the pipe and the adsorption end of the clamp, so as to avoid residual crystallization of polishing liquid.

[0035] The sensor is a photoelectric sensor or a capacitive sensor.

[0036] In an optimized implementation, a first valve 13 is provided on the first adsorption tube section 7, and the first valve 13 is located between the anti-backflow tank 5 and the side connection point.

[0037] In an optimized implementation, a second valve 14 is provided on the purging pipe 9.

[0038] The working principle of this wafer polishing device is as follows: an anti-backflow tank 5 is installed on the pipeline between the clamp adsorption end and the vacuum pump 3, and a blower 6 is connected to the first adsorption pipe section 7. The anti-backflow tank 5 is relatively large and is equipped with a filter element 12, which can effectively prevent polishing liquid and water vapor from entering the vacuum pump. When there is polishing liquid in the anti-backflow tank 5, the tank can be cleaned periodically. At the same time, a first valve 13 and a blower 6 with a second valve 14 are added in front of the anti-backflow tank 5. During normal polishing operation, the second valve 14 is closed and the first valve 13 is opened. Vacuum pump 3 operates normally, providing a vacuum environment for the pipeline. After polishing, the polished workpiece is removed, the first valve 13 is closed, the second valve 14 is opened, and the blower 6 operates to blow out the residual polishing liquid in the first adsorption tube section 7 from the clamp adsorption end, which can effectively solve the problem of residual polishing liquid in the pipeline. During routine maintenance, the second valve 14 can also be closed, the first valve 13 opened, and the clamp adsorption end placed in a water basin. Water is then introduced into the anti-backflow tank 5 through the clamp adsorption end and the first adsorption tube section 7, which can achieve the effect of cleaning the pipeline.

[0039] Furthermore, any content not described in detail in this specification is existing technology known to those skilled in the art.

[0040] Those skilled in the art will understand that this invention can be implemented in many other specific forms without departing from the spirit and scope of this invention. Although embodiments of this invention have been described, it should be understood that this invention is not limited to these embodiments, and those skilled in the art can make changes and modifications within the spirit and scope of this invention as defined in the appended claims.

Claims

1. A wafer polishing apparatus, comprising a polishing platform, a fixture, and a vacuum pump, wherein the fixture is provided with an adsorption end for adsorbing a workpiece to be processed, characterized in that, It also includes an anti-backflow tank, which has a accommodating cavity. The adsorption end is connected to the accommodating cavity of the anti-backflow tank through a first adsorption tube section. The vacuum pump is connected to the accommodating cavity of the anti-backflow tank through a second adsorption tube section. The anti-backflow tank is equipped with a filter element for filtering the polishing liquid, and the second adsorption tube section is connected to the filter element.

2. The wafer polishing apparatus according to claim 1, characterized in that, The filter element is an activated carbon filter element.

3. The wafer polishing apparatus according to claim 1, characterized in that, The anti-backflow can includes a can body and a can lid, with the can lid covering the can body and the filter element being detachably mounted on the can lid.

4. The wafer polishing apparatus according to claim 1, characterized in that, It also includes a blower, which is connected in parallel to the first adsorption tube section via a purging pipe.

5. The wafer polishing apparatus according to claim 4, characterized in that, The connection point between the purging pipe and the first adsorption pipe section is located near the anti-backflow tank.

6. The wafer polishing apparatus according to claim 5, characterized in that, The first adsorption tube section is equipped with a first valve, which is located between the anti-backflow tank and the bypass point.

7. The wafer polishing apparatus according to claim 4, characterized in that, The first adsorption tube section is equipped with a sensor for monitoring the liquid.

8. The wafer polishing apparatus according to claim 4, characterized in that, The purging pipe is equipped with a second valve.

9. The wafer polishing apparatus according to claim 1, characterized in that, The anti-backflow tank is equipped with a level gauge.

10. The wafer polishing apparatus according to claim 1, characterized in that, The bottom of the anti-backflow tank is equipped with a drain outlet.

Images