Wafer grabbing mechanism, polishing device and application

Abstract

The application discloses a wafer grabbing mechanism, a polishing device and application, the wafer grabbing mechanism includes a support, the lower end of the support is provided with a film layer, a plurality of first air pipes are arranged on the support, one end of the first air pipe is connected with a gas supply device, and the other end is used for adsorbing and fixing a wafer, the outer wall of the film layer is provided with a gasket, the gasket is an annular structure, the inner side wall of the lower end of the gasket is in contact with the side wall of the wafer, the gasket is made of elastic porous material, and the wafer grabbing mechanism further includes a second air pipe in communication with the gasket.The gasket and the second air pipe are added on the basis of the existing grabbing mechanism, the gasket is inflated to expand and exert pressure on the side wall of the wafer, so that impurities and particles on the side wall of the wafer are removed.

Description

Technical Field

[0001] This invention relates to the field of semiconductor technology, specifically to wafer gripping mechanisms, polishing devices, and their applications. Background Technology

[0002] As the integration density of semiconductor wafers increases, planarization becomes increasingly important, and Chemical Mechanical Polishing (CMP) is a manufacturing technology used to achieve wafer planarization. CMP is often used when foreign matter on the wafer surface and sidewalls cannot be removed by cleaning or other processes.

[0003] CMP (Chemical Metal Polishing) is a technique that uses a slurry to mechanically and chemically polish wafers on a CMP rotary table. The state of the wafer changes after the CMP process due to the phenomena occurring on the wafer surface and the rotary table surface. Therefore, the CMP process requires a slurry, a rotary table, and a device structure (i.e., a wafer gripping mechanism) to bring the wafer and rotary table surfaces into contact.

[0004] A schematic diagram of an existing wafer gripping mechanism for gripping wafers is shown below. Figure 1 As shown: After the wafer gripper fixes the wafer horizontally, it comes into contact with the turntable surface. In addition, while gripping and fixing the wafer, the wafer gripper rotates a certain amount. This rotational motion affects the mechanical grinding process.

[0005] Existing wafer gripping mechanisms can only remove impurities and particles from the front side of the wafer during polishing, but not from the sidewalls. Therefore, the primary semiconductor process for removing impurities and particles from the wafer sides is cleaning. This process involves bringing the relevant areas into contact with a brush or sponge, then rotating the wafer at a certain speed to remove impurities and particles. However, due to the characteristics of the brush or sponge material, the force applied to the surface is limited. Therefore, when the adhesion of impurities and particles from the wafer sidewalls to the wafer surface is high, cleaning may fail to remove them. Summary of the Invention

[0006] The purpose of this invention is to provide a wafer gripping mechanism that can not only grip the wafer for front-side polishing, but also remove impurities and particles from the wafer sidewalls after the CMP process.

[0007] Furthermore, the present invention also provides a polishing apparatus including the above-described wafer gripping mechanism and its application.

[0008] This invention is achieved through the following technical solution:

[0009] A wafer gripping mechanism includes a support with a film layer at its lower end. Several first air tubes are mounted on the support, one end of which is connected to a gas supply device, and the other end is used to adsorb and fix the wafer. A pad with an annular structure is provided on the outer wall of the film layer, and the inner sidewall of the lower end of the pad contacts the sidewall of the wafer. The pad is made of an elastic porous material. The mechanism also includes a second air tube communicating with the pad, with its end connected to the gas supply device. Gas can be pressurized in both the second and first air tubes, and the gas can be air or the like.

[0010] In existing technologies, such as Figure 1 As shown, the gripping mechanism is used directly to grip the back side of the wafer. The first air tube can apply air pressure in the direction of gravity or the opposite direction to gravity, ensuring the wafer does not fall in the direction of gravity. Because it is in direct contact with the entire back side of the wafer, a cushioning film is placed at the bottom of the support. The support is typically made of a rigid circular plate, such as stainless steel. This type of support structure is very suitable for applying pressure while gripping the back side of the wafer or preventing the wafer from falling downwards. Existing gripping mechanisms do not have a structure that applies mechanical force by pressurizing the wafer sidewalls, therefore they do not have the function of removing impurities and particles from the wafer sidewalls.

[0011] The elastic porous material described in this invention specifically refers to a material that can expand in an inflated state, and the substrate can be attached to the outer wall of the film layer using a heat shrinking process.

[0012] This invention adds a liner and a second air tube to the existing gripping mechanism. Since the liner is made of an elastic porous material, it can expand when inflated, thereby applying pressure to the wafer sidewall to remove impurities and particles from the wafer sidewall.

[0013] The principle of this invention for removing impurities and particles from the wafer sidewalls is as follows:

[0014] After the CMP process is completed, with the wafer held in place by the film layer, gas is pressurized in a second gas tube and then injected into the gasket attached to the outside of the film layer, causing the gasket to expand. This expansion force on the gasket becomes the driving force of the friction on the gasket surface, which removes foreign matter and particles from the wafer sidewalls.

[0015] Furthermore, the material used for the liner has a hardness of 10-60, an elongation of 300%-500%, a porosity of 50-80%, and the pore diameter of the liner is 40-80 μm.

[0016] Materials with the above-mentioned properties can meet the needs of the present invention (enabling the pad to expand in an inflated state).

[0017] Furthermore, the liner is made of polyurethane.

[0018] Furthermore, the top of the liner is lower than or flush with the top of the membrane layer.

[0019] Avoiding excessive padding means that it may affect the gripping mechanism.

[0020] Furthermore, the bottom of the pad is higher than the front side height of the wafer.

[0021] If the bottom of the pad is too low, it will affect the CMP process's ability to polish the front side of the wafer.

[0022] Furthermore, the second trachea is made of transparent plastic.

[0023] The transparent plastics include PFA, PTFE, and polyurethane.

[0024] Preferably, the radius of the second trachea is 0.1 mm to 10 mm.

[0025] Furthermore, multiple second air tubes are provided, and these multiple second air tubes are evenly arranged in the circumferential direction of the liner.

[0026] Furthermore, the support is a disc structure made of stainless steel, the lower end of the disc structure extends radially outward to form an annular protrusion, the upper end of the membrane layer is provided with an annular cavity that mates with the annular protrusion, and an adhesive layer is provided between the bottom of the disc structure and the membrane layer.

[0027] The membrane layer is fitted onto the bottom of the support by the cooperation of the annular cavity and the annular protrusion, and the stability of the connection between the membrane layer and the support is improved by the adhesive layer.

[0028] A wafer polishing apparatus includes the aforementioned wafer gripping mechanism and a turntable for polishing the front side of the wafer, the turntable being disposed below the wafer gripping mechanism.

[0029] Application of wafer gripping mechanisms or wafer polishing devices in wafer polishing.

[0030] Compared with the prior art, the present invention has the following advantages and beneficial effects:

[0031] 1. The present invention adds a liner and a second air pipe to the existing gripping mechanism. When the liner is inflated, it expands and applies pressure to the sidewall of the wafer to remove impurities and particles from the sidewall of the wafer.

[0032] 2. This invention can use the same set of equipment to remove impurities and particles from the front and sidewalls of the wafer, effectively improving the yield of the wafer sidewalls.

[0033] 3. This invention eliminates the need for a separate cleaning process to clean the wafer sidewalls after the CMP process, saving steps and improving work efficiency.

[0034] 4. This invention is the first to propose a technical concept of using CMP process equipment to remove impurities and particles from the wafer sidewalls, providing a new approach to wafer planarization. Attached Figure Description

[0035] The accompanying drawings, which are included to provide a further understanding of embodiments of the invention and form part of this application, do not constitute a limitation thereof. In the drawings:

[0036] Figure 1 This is a schematic diagram of an existing gripping mechanism used to grip wafers;

[0037] Figure 2 This is a schematic diagram of the gripping mechanism of the present invention used for gripping wafers.

[0038] The attached diagram shows the markings and corresponding component names:

[0039] 1-Support, 2-Membranes, 3-First trachea, 4-Pad, 5-Second trachea, 6-Wafer. Detailed Implementation

[0040] To make the objectives, technical solutions, and advantages of the present invention clearer, the present invention will be further described in detail below with reference to the embodiments and accompanying drawings. The illustrative embodiments and descriptions of the present invention are only used to explain the present invention and are not intended to limit the present invention.

[0041] Example 1:

[0042] like Figure 2 As shown, the wafer gripping mechanism includes a support frame 1. A film layer 2 is provided at the lower end of the support frame 1. Several first air pipes 3 are provided on the support frame 1. One end of each first air pipe 3 is connected to an air supply device, and the other end is used to adsorb and fix the wafer 6. A pad 4 is provided on the outer wall of the film layer 2. The pad 4 has a ring structure. The inner sidewall of the lower end of the pad 4 contacts the sidewall of the wafer 6. The pad 4 is made of an elastic porous material. The mechanism also includes a second air pipe 5 connected to the pad 4. The end of the first air pipe 3 is connected to the air supply device. The gas can be pressurized in both the second air pipe 5 and the first air pipe 3. The gas can be air or the like.

[0043] In this embodiment, the support 1 is a disc structure made of stainless steel. The lower end of the disc structure extends radially outward to form an annular protrusion. The upper end of the film layer 2 is provided with an annular cavity that cooperates with the annular protrusion. An adhesive layer is provided between the bottom of the disc structure and the film layer 2. Since the size of the film layer 2 is larger than the size of the wafer 6, the liner 4 has an L-shaped cross-section in its axial direction. That is, the liner 4 is a hollow boss structure. The inner wall of the large end of the boss structure is in close contact with the outer wall of the film layer 2, and the inner wall of the small end of the boss structure is in close contact with the inner wall of the wafer 6.

[0044] In this embodiment, the second air tube 5 is an L-shaped structure. The horizontal section of the L-shaped structure passes through the membrane layer 2 and communicates with the liner 4. The vertical section is set inside the support 1 and communicates with the air supply device after passing through the support 1.

[0045] In this embodiment, the back side of the wafer 6 is gripped by the adsorption of the first air tube 3. After the front side of the wafer 6 is polished by the CMP process, while the first air tube 3 is still adsorbing and gripping the wafer 6, the second air tube 5 is turned on. Air is injected into the pad 4 through the second air tube 5, causing the pad 4 to expand. The inner wall of the expanded pad 4 generates friction against the side wall of the wafer 6, thereby removing impurities and particles from the side wall of the wafer 6.

[0046] Example 2:

[0047] This embodiment is based on embodiment 1. The material of the liner 4 is polyurethane. The hardness of the material used for the liner 4 is 10-60, the elongation is 300%-500%, the porosity is 50-80%, and the pore diameter of the pores in the liner 4 is 40-80 μm.

[0048] Example 3:

[0049] This embodiment is based on embodiment 1. The top of the pad 4 is lower than the top of the film layer 2, or the top of the pad 4 is flush with the top of the film layer 2; the bottom of the pad 4 is higher than the front side height of the wafer 6, that is, the pad 4 does not completely cover the sidewall of the wafer 6.

[0050] Example 4:

[0051] This embodiment is based on embodiment 1. The second air tube 5 is made of transparent plastic, which can be polyurethane, PFA or PTFE. Multiple second air tubes 5 are provided, and the multiple second air tubes 5 are evenly arranged in the circumferential direction of the pad 4.

[0052] Example 5:

[0053] A wafer polishing apparatus includes a wafer gripping mechanism as described in any one of Examples 1-4, and a turntable for polishing the front side of a wafer 6, the turntable being disposed below the wafer gripping mechanism.

[0054] The specific embodiments described above further illustrate the purpose, technical solution, and beneficial effects of the present invention. It should be understood that the above description is only a specific embodiment of the present invention and is not intended to limit the scope of protection of the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A wafer gripping mechanism, comprising a support (1), wherein a film layer (2) is disposed at the lower end of the support (1), and a plurality of first air tubes (3) are disposed on the support (1), one end of each first air tube being connected to an air supply device, and the other end being used to adsorb and fix the wafer, characterized in that, The outer wall of the film layer (2) is provided with a liner (4), which is a ring structure. The inner sidewall of the lower end of the liner (4) is in contact with the sidewall of the wafer (6). The liner (4) is made of an elastic porous material and also includes a second air pipe (5) connected to the liner (4). The second air pipe (5) inflates the liner (4) to make the liner (4) expand. The inner wall of the expanded liner (4) applies pressure to the sidewall of the wafer (6) to remove impurities and particles from the sidewall of the wafer (6). The top of the pad (4) is lower than the top of the membrane layer (2), or the top of the pad (4) is flush with the top of the membrane layer (2); The bottom of the pad (4) is higher than the front side height of the wafer (6); Multiple second air tubes (5) are provided, and the multiple second air tubes (5) are evenly arranged in the circumferential direction of the pad (4).

2. The wafer gripping mechanism according to claim 1, characterized in that, The material used for the liner (4) has a hardness of 10 to 60, an elongation of 300% to 500%, and a porosity of 50 to 80%. The pore size of the liner (4) is 40 to 80 μm.

3. The wafer gripping mechanism according to claim 1, characterized in that, The liner (4) is polyurethane.

4. The wafer gripping mechanism according to claim 1, characterized in that, The second trachea (5) is made of transparent plastic.

5. The wafer gripping mechanism according to any one of claims 1-4, characterized in that, The support (1) is a disc structure made of stainless steel. The lower end of the disc structure extends radially outward to form an annular protrusion. The upper end of the membrane layer (2) is provided with an annular cavity that cooperates with the annular protrusion. An adhesive layer is provided between the bottom of the disc structure and the membrane layer (2).

6. A wafer polishing apparatus, characterized in that, The wafer gripping mechanism as described in any one of claims 1-5 further includes a turntable for polishing the front side of the wafer (6), the turntable being disposed below the wafer gripping mechanism.

7. The application of a wafer gripping mechanism as described in any one of claims 1-5 in wafer polishing.

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