Cooling wafer grinding head

Abstract

The cooling wafer grinding head comprises a grinding head body, a main shaft, an air pressure plate and a grinding pad, one end of the main shaft is fixedly connected with the grinding head body, the other end of the main shaft is connected with an external power source, the air pressure plate is located in the grinding head body, and an air inflation chamber is formed between the air pressure plate and the grinding head body. A pressure film is arranged at the bottom of the air pressure plate, a protective ring is arranged at the bottom of the pressure film, the grinding pad is located below the protective ring, a containing cavity for containing a wafer is formed among the pressure film, the protective ring and the grinding pad, a thickening layer is arranged on the edge of the face, adsorbing the wafer, of the pressure film, a mounting groove is formed in the grinding pad, and a cooling plate is arranged in the mounting groove. A water inlet main pipe and a water outlet main pipe are arranged on the cooling plate. According to the wafer grinding head with the cooling function, the cooling water path is arranged in the grinding pad, so that the overall temperature of the grinding head is reduced, and a wafer on one side of the polishing head is efficiently cooled.

Description

Technical Field

[0001] The utility model relates to the technical field of chemical mechanical polishing, in particular to a wafer polishing head for cooling and temperature reduction. Background Art

[0002] Chemical mechanical polishing (CMP) technology is regarded as an advanced technology in the prior art that can achieve global planarization of the wafer surface in integrated circuit (IC) manufacturing, and can reach an ultra-high flatness at the atomic level. Its effect directly affects the final quality and yield of the chip. When forming large-scale integrated circuits on various semiconductor substrates such as silicon and silicon carbide, an exposure device is required to burn wiring on the wafer. At this time, if the wafer is uneven, the circuit will not be clearly imprinted. To achieve this planarization, a CMP device needs to be used for polishing.

[0003] The structure of the wafer polishing head is the core component of the CMP device, and its polishing head carries the wafer for rotary polishing. In the prior art, during the polishing process using a CMP device, a CMP paste abrasive is impregnated on the polishing plate / pad, and the polishing head holding the wafer is pressed on the polishing plate (fixed plate). While rotating the polishing head and the fixed plate, the chemical reaction generated by the CMP paste abrasive is utilized to achieve planarization. Since the heat generated during the high-speed grinding process is very large, the temperature of the overall structure of the polishing head increases. If the temperature is not reduced in time, the flatness of the wafer grinding will be uneven. Therefore, it is necessary to design a wafer polishing head that can cool and reduce the temperature. Summary of the Utility Model

[0004] The purpose of the utility model is to provide a wafer polishing head for cooling and temperature reduction, which reduces the overall temperature of the polishing head by arranging a cooling water channel inside the polishing pad, and enables efficient cooling of the wafer on the side of the polishing head.

[0005] To achieve the above purpose, the utility model provides a wafer polishing head for cooling and temperature reduction, including a polishing head body, a main shaft, a pneumatic plate, and a polishing pad. One end of the main shaft is fixedly connected to the polishing head body, and the other end is connected to an external power source. The pneumatic plate is located inside the polishing head body, and an inflation chamber is formed between the pneumatic plate and the polishing head body. A pressure film is provided at the bottom of the pneumatic plate, and a retaining ring is provided at the bottom of the pressure film. The polishing pad is located below the retaining ring, and a receiving cavity for accommodating the wafer is formed among the pressure film, the retaining ring, and the polishing pad. A thickened layer is provided at the edge of the surface of the pressure film that adsorbs the wafer. An installation groove is provided inside the polishing pad, and a cooling plate is provided in the installation groove. The cooling plate is provided with a main water inlet pipe and a main water outlet pipe. The main water inlet pipe is arranged in a large arc shape, and the main water outlet pipe is arranged in a small arc shape.

[0006] Preferably, a plurality of inflation pipes are provided inside the main shaft, and one end of each inflation pipe is communicated with the inflation chamber.

[0007] Preferably, the grinding head body is in an inverted concave shape, and both ends of the air pressure plate are in sliding contact with the inner wall of the grinding head body.

[0008] Preferably, the outer diameter of the retaining ring is the same as that of the pressure film, and the inner diameter of the retaining ring coincides with the outer diameter of the thickened layer, and the thickened layer is arranged along the circumferential direction of the pressure film.

[0009] Preferably, a plurality of cross-flow branch pipes arranged horizontally are provided on the main water inlet pipe, and a plurality of longitudinal-flow branch pipes arranged longitudinally are provided on the main water outlet pipe.

[0010] Preferably, the cross-flow branch pipes are arranged above the longitudinal-flow branch pipes. Both ends of the cross-flow branch pipes are communicated with the main water inlet pipe. One end of the longitudinal-flow branch pipe is communicated with the main water inlet pipe, and the other end thereof is communicated with the main water outlet pipe.

[0011] Preferably, the main water inlet pipe is communicated with an external cooling water inlet, and the main water outlet pipe is communicated with an external cooling water recovery device.

[0012] Therefore, the present utility model adopts the above-mentioned wafer grinding head for cooling and temperature reduction. By arranging a cooling water path inside the grinding pad, the overall temperature of the grinding head is reduced, so that the wafer on one side of the polishing head can be efficiently cooled. By arranging a thickened layer at the edge of the pressure film, the wear resistance of the pressure film is improved, and its service life is prolonged.

[0013] The technical solution of the present utility model will be further described in detail below with reference to the drawings and embodiments. Description of the Drawings

[0014] Figure 1 is the front view of a wafer grinding head for cooling and temperature reduction of the present utility model;

[0015] Figure 2 is the cross-sectional view of the pressure film in a wafer grinding head for cooling and temperature reduction of the present utility model;

[0016] Figure 3 is the schematic diagram of the pressure film in a wafer grinding head for cooling and temperature reduction of the present utility model;

[0017] Figure 4 is the schematic diagram of the cooling plate in a wafer grinding head for cooling and temperature reduction of the present utility model.

[0018] Reference Numerals

[0019] 1, spindle; 2, grinding head body; 3, pressure film; 4, wafer; 5, cooling plate; 6, grinding pad; 7, retaining ring; 8, air pressure plate; 9, inflation chamber; 10, inflation pipe; 11, thickened layer; 12, main water inlet pipe; 13, main water outlet pipe; 14, cross-flow branch pipe; 15, longitudinal-flow branch pipe. Detailed Embodiments

[0020] The technical solution of the present utility model will be further described below with reference to the drawings and embodiments.

[0021] Unless otherwise defined, the technical terms or scientific terms used in the present utility model shall have the ordinary meanings understood by those with ordinary skills in the field to which the present utility model belongs. The "first", "second" and similar words used in the present utility model do not indicate any order, quantity or importance, but are only used to distinguish different components. Words such as "including" or "comprising" mean that the elements or objects appearing before this word cover the elements or objects listed after this word and their equivalents, without excluding other elements or objects. Words such as "connected" or "coupled" are not limited to physical or mechanical connections, but may include electrical connections, whether direct or indirect. "Upper", "lower", "left", "right", etc. are only used to represent relative position relationships. When the absolute position of the object being described changes, the relative position relationship may also change accordingly.

[0022] Embodiment

[0023] As Figure 1 shown, a wafer 4 grinding head for cooling and temperature reduction includes a grinding head body, a main shaft 1, a pneumatic plate 8, and a grinding pad 6. One end of the main shaft 1 is fixedly connected to the grinding head body, and the other end is connected to an external power source (not shown in the figure). The external power source drives the main shaft 1 to rotate, thereby driving the overall structure of the grinding head to rotate to grind the wafer 4. The pneumatic plate 8 is located inside the grinding head body 2, and the grinding head body 2 is in an inverted concave shape. Both ends of the pneumatic plate 8 are in sliding contact with the inner wall of the grinding head body 2. An inflation chamber 9 is formed between the pneumatic plate 8 and the grinding head body 2. A plurality of inflation pipes 10 are provided inside the main shaft 1, and one end of each inflation pipe 10 is communicated with the inflation chamber 9. The other end of the inflation pipe 10 is connected to an external inert gas source (not shown in the figure). The external inert gas source fills the gas into the inflation chamber 9 through the inflation pipe 10, so that the pressure film 3 is inflated to press on the wafer 4, and the wafer 4 is ground on the grinding pad 6.

[0024] A pressure film 3 is provided at the bottom of the pneumatic plate 8, a retaining ring 7 is provided at the bottom of the pressure film 3, the grinding pad 6 is located below the retaining ring 7, and the outer diameter of the retaining ring 7 is the same as the outer diameter of the pressure film 3. A receiving cavity for receiving the wafer 4 is formed among the pressure film 3, the retaining ring 7, and the grinding pad 6, and the wafer 4 is located in the receiving cavity on the grinding pad 6. As Figure 2 shown, a thickened layer 11 is provided at the edge of the side of the pressure film 3 that adsorbs the wafer 4, and the inner diameter of the retaining ring 7 coincides with the outer diameter of the thickened layer 11. The thickened layer 11 is arranged along the circumferential direction of the pressure film 3. In the prior art, the pressure film 3 prepared by traditional processes has a relatively thin thickness during the grinding process. The angular velocity at the edge position of the film is the highest, resulting in the largest frictional force at the outermost edge of the pressure film 3 during the grinding process, and the edge of the pressure film 3 is easily worn. As Figure 3As shown, by providing a thickened layer 11 at the edge of the pressure film 3, the thickness of the edge of the pressure film 3 is increased, improving the wear resistance of the pressure film 3. The pressure film 3 is not easily worn, and the service life of the pressure film 3 is extended.

[0025] As Figure 4 shown, the polishing pad 6 is internally provided with a mounting groove. The polishing pad 6 is circular. A cooling plate 5 is provided in the mounting groove. A main water inlet pipe 12 and a main water outlet pipe 13 are provided on the cooling plate 5. One ends of the main water inlet pipe 12 and the main water outlet pipe 13 penetrate through the side wall of the polishing pad 6 and are communicated with an external water source. The main water inlet pipe 12 is arranged in a large arc shape, and the main water outlet pipe 13 is arranged in a small arc shape. The main water inlet pipe 12 and the main water outlet pipe 13 can generally enclose a circle, which is adapted to the shape of the polishing pad 6.

[0026] The main water inlet pipe 12 is communicated with an external cooling water inlet (not shown in the figure), and the main water outlet pipe 13 is communicated with an external cooling water recovery device (not shown in the figure).

[0027] The external cooling water enters the cooling plate 5 through the main water inlet pipe 12. The polishing pad 6 is cooled by the cooling water, reducing the temperature between the polishing pad 6 and the wafer 4 to make the polishing flatness of the wafer 4 uniform. The used cooling water is discharged from the cooling plate 5 through the main water outlet pipe 13 and enters the cooling water recovery device.

[0028] The flow of the cooling water on the cooling plate 5 is as Figure 4 shown by the arrows in the figure. A plurality of cross-flow branch pipes 14 arranged horizontally are provided on the main water inlet pipe 12, and a plurality of longitudinal-flow branch pipes 15 arranged longitudinally are provided on the main water outlet pipe 13. Both ends of the cross-flow branch pipes 14 are communicated with the main water inlet pipe 12. One end of the longitudinal-flow branch pipe 15 is communicated with the main water inlet pipe 12, and the other end thereof is communicated with the main water outlet pipe 13. The cooling water enters the cross-flow branch pipes 14 through the main water inlet pipe 12, then enters the main water inlet pipe 12, and then enters the longitudinal-flow branch pipes 15. The used cooling water in the longitudinal-flow branch pipes 15 is discharged from the cooling plate 5 through the main water outlet pipe 13.

[0029] The cross-flow branch pipes 14 are arranged above the longitudinal-flow branch pipes 15. The cooling water flows in the cross-flow branch pipes 14, and the used cooling water flows in the longitudinal-flow branch pipes 15. The cooling water in the cross-flow branch pipes 14 cools the heat generated during the polishing of the polishing pad 6.

[0030] During use, the wafer 4 is placed on the polishing pad 6 and located within the accommodating cavity. An external inert gas source is used to inflate the inflation pipe 10 to fill the inflation chamber 9 with gas. The pressure film 3 is inflated to exert pressure on the wafer 4. The main shaft 1 is driven to rotate by an external power source, driving the grinding head to rotate. The wafer 4 is ground on the polishing pad 6, and friction is generated between the wafer 4 and the pressure film 3. By providing a thickened layer 11 at the edge of the pressure film 3, the thickness of the edge of the pressure film 3 is increased, improving the wear resistance of the pressure film 3. The pressure film 3 is not easily worn, extending its service life. Heat is generated during the grinding of the wafer 4. External cooling water enters the main inlet pipe 12 and then enters the cross-flow branch pipes 14. The cooling water in the cross-flow branch pipes 14 cools the polishing pad 6, reducing the friction temperature between the wafer 4 and the polishing pad 6, making the grinding flatness of the wafer 4 uniform. The cooled cooling water is discharged from the cooling plate 5 through the longitudinal flow branch pipes 15 and the main outlet pipe 13. By providing the cooling plate 5 within the polishing pad 6, efficient cooling of the wafer 4 can be achieved.

[0031] Therefore, the present utility model adopts the above-mentioned wafer grinding head with a cooling and temperature reduction function. By providing a cooling water path within the polishing pad, the overall temperature of the grinding head is reduced, enabling efficient cooling of the wafer on one side of the polishing head. By providing a thickened layer at the edge of the pressure film, the wear resistance of the pressure film is improved, extending its service life.

[0032] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present utility model and are not intended to limit them. Although the present utility model has been described in detail with reference to the preferred embodiments, those of ordinary skill in the art should understand that they can still modify or equivalently replace the technical solutions of the present utility model, and these modifications or equivalent replacements do not cause the modified technical solutions to deviate from the spirit and scope of the technical solutions of the present utility model.

Claims

1. A cooling wafer grinding head, characterized in that: It includes a grinding head body, a spindle, an air pressure plate, and a grinding pad. One end of the spindle is fixedly connected to the grinding head body, and the other end is connected to an external power source. The air pressure plate is located inside the grinding head body, and an air-filled chamber is formed between the air pressure plate and the grinding head body. A pressure membrane is provided at the bottom of the air pressure plate, and a guard ring is provided at the bottom of the pressure membrane. The grinding pad is located below the guard ring. An accommodating cavity for accommodating wafers is formed between the pressure membrane, the guard ring, and the grinding pad. A thickened layer is provided at the edge of one side of the pressure membrane for adsorbing the wafer. A mounting groove is provided inside the grinding pad, and a cooling plate is provided in the mounting groove. A water inlet pipe and a water outlet pipe are provided on the cooling plate. The water inlet pipe is arranged in a large arc shape, and the water outlet pipe is arranged in a small arc shape.

2. The cooling wafer grinding head according to claim 1, characterized in that: A plurality of inflation tubes are arranged inside the main shaft, and one end of the inflation tube is communicated with the inflation chamber.

3. The cooling wafer grinding head according to claim 1, characterized in that: The grinding head body is in an inverted concave shape, and two ends of the air pressure plate are in sliding contact with the inner wall of the grinding head body.

4. The cooling wafer grinding head according to claim 1, characterized in that: The outer diameter of the retaining ring is consistent with the outer diameter of the pressure membrane, the inner diameter of the retaining ring coincides with the outer diameter of the thickened layer, and the thickened layer is arranged along the circumference of the pressure membrane.

5. The cooling wafer grinding head according to claim 1, characterized in that: The water inlet main pipe is provided with a plurality of transverse flow branches arranged transversely, and the water outlet main pipe is provided with a plurality of longitudinal flow branches arranged longitudinally.

6. The cooling wafer grinding head according to claim 5, characterized in that: The cross flow branch pipe is arranged above the longitudinal flow branch pipe, both ends of the cross flow branch pipe are connected to the water inlet main pipe, one end of the longitudinal flow branch pipe is connected to the water inlet main pipe, and the other end is connected to the water outlet main pipe.

7. The cooling wafer grinding head according to claim 1, characterized in that: The water inlet pipe is communicated with an external cooling water inlet, and the water outlet pipe is communicated with an external cooling water recovery device.

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