CN101691024A - Spindle structure for rough grinding and accurate grinding combined grinding wheel for semiconductor chips - Google Patents

Abstract

The invention relates to a combined grinding wheel main shaft structure for rough grinding and fine grinding of semiconductor wafers. Its double-spindle structure semiconductor wafer grinder is simplified to a single-spindle structure grinder, which greatly saves costs, and its thickness after grinding is controllable; the axis of the grinding wheel spindle has not changed, and the surface shape of the semiconductor wafer has also ensured consistency. high quality. It includes a central shaft, a grinding wheel seat, a coarse grinding wheel, and a fine grinding wheel. A central through hole is opened in the center of the central shaft, and the grinding wheel seat is installed at the bottom end of the central shaft. It is characterized in that: the bottom part of the grinding wheel seat It is a central support end, an inner circle installation end and an outer circle installation end, the outer circle installation end is equipped with the fine grinding wheel, the piston is installed in the cavity of the inner circle installation end, and the coarse grinding wheel is installed on the piston The lower end surface of the piston, the piston end surface and the grinding wheel seat enclose an air cavity, the air cavity communicates with the vent pipe in the central through hole through the gas channel, and the vent pipe is connected to an external air pressure control system.

Description

Combination grinding wheel spindle structure for rough grinding and fine grinding of semiconductor wafer

(1) Technical field

The invention relates to the technical field of semiconductor wafer processing equipment, in particular to a combined grinding wheel spindle structure for rough grinding and fine grinding of semiconductor wafers.

(2) Background technology

The grinding of existing semiconductor wafers is generally completed through two processes of rough grinding and fine grinding. Different processes use grinding wheels with different particle sizes, that is, the rough grinding process uses coarse grinding wheels with larger abrasive grains to improve the grinding process. Efficiency, the fine grinding process uses a coarse grinding wheel with a smaller abrasive grain size to improve the grinding quality. The specifications of the main shaft on the rough grinding station and the main shaft on the fine grinding station are exactly the same, and the difference is that the grinding wheels installed on the grinding wheel main shaft are respectively a rough grinding wheel and a fine grinding wheel, and the cost is high. And because the rough grinding process and the fine grinding process of the semiconductor wafer are completed on the rough grinding station and the fine grinding station respectively, in the process of station switching, the clamping positioning reference of the semiconductor wafer changes, resulting in the semiconductor wafer after grinding. The thickness dimension is difficult to ensure consistency; at the same time, because the axis of the coarse grinding wheel and the axis of the fine grinding wheel are not consistent, the surface shape of the semiconductor wafer after grinding is inconsistent, and the fine grinding needs to be corrected, and the grinding efficiency is low.

(3) Contents of the invention

In view of the above problems, the present invention provides a combined grinding wheel spindle structure for rough grinding and fine grinding of semiconductor wafers, which can complete the rough grinding and fine grinding of semiconductor wafers at the same station, and can simplify the semiconductor wafer grinder with double spindle structure into a single The grinding machine with the spindle structure can greatly save costs, and the combined grinding wheel spindle uses the same semiconductor wafer clamping reference, and the thickness after grinding is controllable; the axis of the grinding wheel spindle does not change, and the surface shape of the semiconductor wafer also ensures consistency. Cutting quality is high.

Its technical scheme is as follows: it includes a central shaft, a grinding wheel seat, a coarse grinding wheel, and a fine grinding wheel. The center of the central shaft has a central through hole, and the bottom end of the central shaft is equipped with the grinding wheel seat. It is characterized in that : the bottom of the grinding wheel seat is divided into a central support end, an inner circle installation end and an outer circle installation end, the outer circle installation end is equipped with the fine grinding wheel, and the piston is installed in the cavity of the inner circle installation end, so The coarse grinding wheel is installed on the lower end face of the piston, and the end face of the piston and the grinding wheel seat encircle an air cavity, and the air cavity communicates with the vent pipe in the central through hole through the gas channel, and the vent pipe is connected to the external air pressure Control System.

It is further characterized in that: the upper end surface of the piston and the grinding wheel seat enclose an air cavity, and the air cavity communicates with the ventilation pipe in the central through hole through a gas channel;

The upper end surface and the lower end surface of the piston and the grinding wheel seat respectively enclose two disconnected air cavities, and the two disconnected gas cavities are respectively connected to the center through different gas passages connected to each other. a vent pipe in the through hole;

The inner circle installation end and the outer circle installation end of the bottom of the grinding wheel seat are separated by circumferential protrusions;

The cylindrical pins are sequentially connected to the grinding wheel seat, the piston, and the auxiliary gland. The side of the cover close to the central axis is fastened to the central support end by bolts, and the side of the lower end of the piston away from the central axis is fastened to a coarse grinding wheel;

Both ends of the cylindrical pin are respectively fastened to the grinding wheel seat and the auxiliary gland, and the cylindrical pin passes through the piston;

A sealing ring is inlaid in the sealing groove at both ends of the cylindrical pin, and a sealing ring is installed on the side wall of the piston and the grinding wheel seat;

The fine grinding wheel is fastened to the outer circular mounting end by screws;

A long tube with a through hole is installed in the central through hole, the diameter of the long tube is smaller than the diameter of the central through hole, the through hole is connected to the water outlet at the bottom, and the ventilation tube is located on the outer wall of the long tube Inside the gap surrounded by the inner wall of the central through hole;

The sealing end cover is installed at the bottom end of the central through hole, the outer end surface of the sealing end cover is tightly connected to the bottom end of the central shaft, the bottom of the long tube is nested with the upper end surface of the sealing end cover, and the The sealing end cover is provided with the water outlet.

After adopting the above-mentioned structure of the present invention, the air pressure of the air cavity is controlled by the external air pressure control system, thereby driving the piston to slide up and down. When the piston slides to the lowest end, the rough grinding wheel can be When the piston slides to the uppermost end, the coarse grinding wheel retracts simultaneously, and the fine grinding wheel can contact the semiconductor wafer, thereby finely grinding the semiconductor wafer. It simplifies the double-spindle semiconductor wafer grinder into a single-spindle grinder, which can greatly save costs; and the combined grinding wheel spindle uses the same semiconductor wafer clamping reference, and the thickness after grinding is controllable; the axis of the grinding wheel spindle has not changed. The surface shape of the semiconductor wafer also ensures consistency and high grinding quality.

(4) Description of drawings

Fig. 1 is a schematic structural view of Embodiment 1 of the present invention (the left side is the rough grinding state, the right side is the fine grinding state);

Fig. 2 is a schematic structural diagram of Embodiment 2 of the present invention (the left side is the coarse grinding state, and the right side is the fine grinding state).

(5) Specific implementation methods

See Fig. 1, the present invention comprises a central shaft 1, a grinding wheel seat 2, the central shaft 1 has a central through hole, the bottom end of the central shaft 1 is equipped with a grinding wheel seat 2, the bottom of the grinding wheel seat 2 is divided into a central support end 3, and an inner circle for installation End 4 and the outer circle mounting end 5, the outer circle mounting end 5 is equipped with a fine grinding wheel 6, the piston 7 is installed in the cavity of the inner circle mounting end 4, the coarse grinding wheel 8 is installed on the lower end surface of the piston 7, and the piston 7 The end face and the grinding wheel seat 2 encircle an air chamber 9, the air chamber 9 communicates with the vent pipe 11 in the central through hole through the upper gas channel 10, and the vent pipe 11 is connected to an external air pressure control system (not shown in the figure, which is an existing mature technology ), this is the first embodiment of the air pressure channel; the inner circle mounting end 4 and the outer circle mounting end 5 at the bottom of the grinding wheel seat 2 are isolated by the circumferential protrusion 12; the cylindrical pin 13 is connected to the grinding wheel seat 2, the piston 7, and the auxiliary gland 14 in sequence The side of the upper end surface of the auxiliary gland 14 away from the central axis 1 is matched with the side of the lower end surface of the piston 7 close to the central axis 1, and the side of the auxiliary gland 14 close to the central axis 1 is fastened to the central support end 3 by bolts 15, The side of the lower end of the piston 7 away from the central axis 1 is tightly connected with a coarse grinding wheel 8; the two ends of the cylindrical pin 13 are respectively fastened to the grinding wheel seat 2 and the auxiliary gland 14, and the cylindrical pin 13 runs through the piston 7; the sealing of the two ends of the cylindrical pin 13 A sealing ring 16 is inlaid in the groove, and a sealing ring 17 is installed on the side wall of the piston 7 and the grinding wheel seat 2; the fine grinding wheel 6 is fastened to the outer circle mounting end 5 by a screw 18; The long pipe 20, the diameter of the long pipe 20 is smaller than the diameter of the central through hole, the through hole 19 is connected to the water outlet 21 at the bottom, the gap surrounded by the outer wall of the long pipe 20 and the inner wall of the central through hole is the ventilation pipe 11; the sealing end cover 22 The cover is mounted on the bottom of the central through hole, and the outer end surface of the sealing end cover 22 is tightly connected to the bottom of the central shaft 1.

Its working principle is as follows: when performing rough grinding, the external air pressure control system injects compressed air into the air chamber 9 through the air pipe 11 and the gas channel 10, and the compressed air pushes the piston 7 to the bottom, so that the grinding wheel on the rough grinding wheel 8 The teeth 23 are exposed, and the monocrystalline silicon workpiece is roughly ground; when performing fine grinding, the external air pressure control system pumps the air cavity 9 into a vacuum through the vent pipe 11 and the gas channel 10, and the air cavity 9 forms a vacuum, and the piston 7 is sucked to the top , so that the coarse grinding wheel 8 is retracted, and the grinding wheel teeth 24 of the fine grinding wheel 6 are exposed, so that the monocrystalline silicon workpiece is finely ground.

As shown in Figure 2, a long tube 20 with a through hole 19 is installed in the central through hole. The diameter of the long tube 20 is smaller than the diameter of the central through hole. The air pipe 11 and the air pipe 27 are installed in the enclosed gap; the sealing end cover 22 is installed at the bottom of the central through hole, the outer end surface of the sealing end cover 22 is fastened to the bottom of the central axis 1, and the bottom of the long pipe 20 is connected to the bottom of the central shaft. The upper end surface of the sealing end cover 22 is nested and installed, and the sealing end cover 22 has a water outlet 21; the upper end surface of the piston 7 and the grinding wheel seat 2 form an upper air chamber 9, and the upper air chamber 9 communicates with the central through hole through the upper gas passage 10. Vent pipe 11, the lower end surface of piston 7 and grinding wheel seat 2, auxiliary gland 14, rough grinding wheel 8 four surround air chamber 26, and air chamber 26 communicates with the vent pipe 27 in the center hole through lower gas channel 25, The vent pipe 11 and the vent pipe 27 are connected to an external air pressure control system (not shown in the figure, which is an existing mature technology), which is the second embodiment of the air pressure passage.

Its working principle is as follows: when performing rough grinding, the external air pressure control system injects compressed air into the upper air chamber 9 through the ventilation pipe 11 and the upper gas passage 10, and the compressed air pushes the piston 7 to the bottom, so that the rough grinding wheel 8 is moved upwards. The grinding wheel teeth 23 are exposed, so that the monocrystalline silicon workpiece is roughly ground; when performing fine grinding, the external air pressure control system injects compressed air into the lower air chamber 26 through the air pipe 27 and the gas channel 25, and the compressed air pushes the piston 7 to the The top end, so that the coarse grinding wheel 8 is retracted, and the grinding wheel teeth 24 of the fine grinding wheel 6 are exposed, so that the monocrystalline silicon workpiece is finely ground.

Of course, if in order to increase the rigidity of driving the rough grinding wheel, the combination of compressed air and vacuuming can also be adopted. That is: when performing rough grinding, the external air pressure control system injects compressed air into the upper air chamber 9 through the vent pipe 11 and the upper gas passage 10, and the compressed air pushes the piston 7 to the bottom; at the same time, the external air pressure control system passes through the vent pipe 27 1. The gas channel 25 evacuates the air chamber 26 into a vacuum, and the air chamber 9 forms a vacuum, and the piston 7 is sucked to the bottom, so that the grinding wheel teeth 23 on the rough grinding wheel 8 are exposed, and the monocrystalline silicon workpiece is roughly ground; During grinding, the external air pressure control system injects compressed air into the lower air cavity 26 through the air pipe 27 and the gas passage 25, and the compressed air pushes the piston 7 to the top, thereby retracting the coarse grinding wheel 8 and the grinding wheel teeth of the fine grinding wheel 6. 24 is exposed, so that the single crystal silicon workpiece is finely ground.

Claims (10)

1. A combined emery wheel spindle structure for semiconductor wafer rough grinding and fine grinding, which comprises a central shaft, a grinding wheel seat, a rough grinding wheel, and a fine grinding wheel, the center of the central shaft has a central through hole, and the bottom end of the central shaft is equipped with a The grinding wheel seat is characterized in that: the bottom of the grinding wheel seat is divided into a central support end, an inner circle installation end and an outer circle installation end, the outer circle installation end is equipped with the fine grinding wheel, and the piston is installed in the inner circle In the cavity of the round mounting end, the rough grinding wheel is installed on the lower end surface of the piston, and the piston end surface and the grinding wheel seat enclose an air cavity, and the air cavity communicates with the air pipe in the central through hole through the gas passage. , the vent pipe is connected to an external air pressure control system. 2. According to claim 1, a combined grinding wheel spindle structure for rough grinding and fine grinding of semiconductor wafers is characterized in that: the upper end surface of the piston and the grinding wheel seat form an air cavity, and the air cavity communicates with the Snorkel in center through hole. 3. According to claim 1, a combined grinding wheel spindle structure for rough grinding and fine grinding of semiconductor wafers is characterized in that: the upper end surface and the lower end surface of the piston respectively form two disconnected air cavities with the grinding wheel seat, The two unconnected air cavities communicate with the vent tube in the central through hole through different gas passages connected to each other. 4 . The combined grinding wheel spindle structure for rough grinding and fine grinding of semiconductor wafers according to claim 1 , characterized in that: the inner circle mounting end and the outer circle mounting end of the bottom of the grinding wheel seat are separated by circumferential protrusions. 5. According to claim 4, a combined grinding wheel spindle structure for rough grinding and fine grinding of semiconductor wafers is characterized in that: cylindrical pins are sequentially connected to the grinding wheel seat, the piston, and the auxiliary gland, and the upper end surface of the auxiliary gland is far away from the One side of the central shaft is installed in cooperation with the side of the lower end surface of the piston close to the central shaft, the side of the auxiliary gland close to the central shaft is fastened to the central support end by bolts, and the lower end surface of the piston is away from the center A rough grinding wheel is fastened on one side of the shaft. 6. According to claim 5, a combined grinding wheel spindle structure for rough grinding and fine grinding of semiconductor wafers is characterized in that: the two ends of the cylindrical pin are respectively fastened to the grinding wheel seat and the auxiliary gland, and the cylindrical pin through the piston. 7. According to claim 6, a combined grinding wheel spindle structure for rough grinding and fine grinding of semiconductor wafers is characterized in that: sealing rings are embedded in the sealing grooves at both ends of the cylindrical pin, and the piston and the side wall of the grinding wheel seat A sealing ring is installed. 8 . The semiconductor wafer rough grinding and fine grinding combined grinding wheel spindle structure according to claim 7 , wherein the fine grinding wheel is fastened to the outer circular mounting end by screws. 9. According to claim 8, a combined grinding wheel spindle structure for rough grinding and fine grinding of semiconductor wafers is characterized in that: a long tube with a through hole is installed in the central through hole, and the diameter of the long tube is smaller than that of the center The diameter of the through hole, the through hole is connected to the water outlet at the bottom, and the ventilation pipe is located inside the gap surrounded by the outer wall of the long tube and the inner wall of the central through hole. 10. According to claim 9, a combined grinding wheel spindle structure for rough grinding and fine grinding of semiconductor wafers is characterized in that: the sealing end cover is mounted on the bottom end of the central through hole, and the outer end surface of the sealing end cover is fastened to the The bottom end of the central shaft, the bottom of the long tube is nested with the upper end surface of the sealing end cover, and the sealing end cover is provided with the water outlet.

Images