Polishing apparatus and polishing method

Abstract

The invention provides a polishing apparatus and a polishing method. The equipment comprises a platform, a polishing pad and a polishing head, the polishing pad is laid on the surface of the platform, the polishing head is in contact with the polishing pad, a polished wafer is arranged between the polishing head and the polishing pad, a spraying device is further arranged on the side face of the polishing head, and the spraying device faces the polished wafer. The spraying equipment comprises a first spraying head for spraying deionized water and a second spraying head for spraying a surface hydrophilic agent, and the spraying equipment is arranged to alternately spray the deionized water and the surface hydrophilic agent to a polished wafer when the polishing head is in a lifting state. The two spraying pipelines are additionally arranged on the side face of the ramming head, alternate washing with deionized water and a surface hydrophilic agent is continuously carried out, and the wafer is kept wet after the ramming head rises and when the ramming head is transferred between platforms. Due to the hydrophobicity of bare silicon, the wafer is not enough to be in a wet state when only deionized water is used for surface moisturizing, particles are easily introduced into the surface of the wafer in the external environment at the moment, and the wafer is difficult to clean in the subsequent process. Therefore, the effect of reducing the surface particle level can be more effectively achieved through alternate flushing of the deionized water and the surface hydrophilic agent.

Description

Technical Field

[0001] The present invention relates to the field of semiconductor equipment, and in particular to a polishing device and a polishing method. Background Art

[0002] Chemical mechanical grinding, also known as chemical mechanical polishing, is a processing technology that combines chemical corrosion and mechanical removal. It is a technology in semiconductor processing technology that can achieve global surface flattening.

[0003] Chemical mechanical polishing technology combines the advantages of chemical polishing and mechanical polishing. Pure chemical polishing has high surface accuracy, low damage, good integrity, and is not prone to surface / subsurface damage, but the polishing rate is slow, the material removal efficiency is low, the surface profile accuracy cannot be corrected, and the polishing consistency is relatively poor; pure mechanical polishing has good polishing consistency, high surface flatness, and high polishing efficiency, but it is prone to surface layer / subsurface layer damage and the surface roughness value is relatively low. Chemical mechanical polishing absorbs the advantages of both, and can obtain a more perfect surface while ensuring material removal efficiency. The flatness obtained is 1-2 orders of magnitude higher than that of using these two types of polishing alone, and can achieve surface roughness from nanometer level to atomic level.

[0004] After the polishing process is completed, if the polished surface can be kept clean, it will be more conducive to the implementation of subsequent processes. Summary of the invention

[0005] The technical problem to be solved by the present invention is to provide a polishing device and a polishing method, which can ensure the cleanliness of the polished surface and are more conducive to the implementation of subsequent processes.

[0006] In order to solve the above problems, the present invention provides a polishing device, including a platform, a polishing pad and a polishing head, the polishing pad is laid on the surface of the platform, the polishing head is in contact with the polishing pad, the polished wafer is placed between the polishing head and the polishing pad, and a spray device is also included on the side of the polishing head. The spray device is arranged toward the polished wafer and includes a first spray head for spraying deionized water and a second spray head for spraying a surface hydrophilic agent. The spray device is arranged to alternately spray deionized water and a surface hydrophilic agent onto the polished wafer when the polishing head is in a raised state.

[0007] Optionally, there are multiple first nozzles; and there are multiple second nozzles.

[0008] Optionally, the first nozzle and the second nozzle are alternately arranged around the blasting head.

[0009] Optionally, the first nozzle and the second nozzle extend to the side of the polishing head through a corrugated tube or a bamboo tube.

[0010] Optionally, the surface hydrophilic agent is selected from one or a mixture of γ-aminopropyltriethoxysilane and polyoxyethylene chain.

[0011] In order to solve the above problems, the present invention provides a polishing method, including: polishing a wafer; lifting the polishing head and transferring the wafer after polishing, and during the lifting and transferring process, using a first spray head and a second spray head to alternately spray deionized water and a surface hydrophilic agent onto the polished wafer.

[0012] Optionally, multiple first nozzles and multiple second nozzles are used.

[0013] Optionally, the first nozzle and the second nozzle are alternately arranged around the blasting head.

[0014] Optionally, the surface hydrophilic agent is selected from one or a mixture of γ-aminopropyltriethoxysilane and polyoxyethylene chain.

[0015] The present invention installs two spray pipes on the side of the polishing head to continuously perform alternating flushing with deionized water and surface hydrophilic agent, so that the wafer is kept moist after the polishing head is raised and when it is transferred between platforms. Due to the hydrophobicity of bare silicon, it is not enough to keep the wafer moist by only using deionized water for surface moisturizing. At this time, the external environment is easy to introduce particles on the surface of the wafer, and it is difficult to clean in the subsequent process. Therefore, alternating flushing with deionized water and surface hydrophilic agent can more effectively achieve the effect of reducing the level of surface particles. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Attached Figure 1 Shown is a schematic structural diagram of a polishing device according to a specific embodiment of the present invention.

[0017] Attached Figure 2 The figure is a schematic diagram of the structure of the polishing head of the polishing equipment according to a specific embodiment of the present invention.

[0018] Attached Figure 3 The figure is a schematic diagram of the structure of the polishing head of the polishing equipment according to a specific embodiment of the present invention.

[0019] Attached Figure 4 Shown is a schematic diagram of the implementation steps of the polishing method described in a specific embodiment of the present invention. DETAILED DESCRIPTION

[0020] The specific implementation modes of the polishing equipment and the polishing method provided by the present invention are described in detail below with reference to the accompanying drawings.

[0021] Attached Figure 1The structure diagram of the polishing device of this specific embodiment is shown, which includes a platform 10, a polishing pad 11, and a polishing head 12. The polishing pad 11 is laid on the surface of the platform 10, the polishing head 12 is in contact with the polishing pad 11, and the wafer 14 to be polished is placed between the polishing head 11 and the polishing pad 12. The wafer 14 can be a wafer of any common semiconductor material including silicon, germanium, silicon carbide, GaAs, and GaN.

[0022] Attached Figure 2 The figure shows a schematic diagram of the structure of the polishing head of the polishing equipment according to a specific embodiment of the present invention. In this specific embodiment, a spraying device 13 is also included on the side of the polishing head 11, and the spraying device is arranged toward the polished wafer 14, and includes a first spray head 131 for spraying deionized water and a second spray head 132 for spraying a surface hydrophilic agent. The first spray head 131 and the second spray head 132 are preferably flexible hoses such as bellows or bamboo tubes that can adjust the height and position. The spraying device 12 is configured to alternately spray deionized water and a surface hydrophilic agent to the polished wafer 14 when the polishing head 12 is in the lifted state shown by the dotted line. In this specific embodiment, the first spray head 131 for spraying deionized water and the second spray head 132 for spraying a surface hydrophilic agent are each one and are arranged oppositely. In this specific embodiment, the polished wafer 14 is a single crystal silicon wafer, and correspondingly, the surface hydrophilic agent is selected from one or a mixture of γ-aminopropyltriethoxysilane and a polyoxyethylene chain, which can make the wafer surface in a hydrophilic state. In other specific implementations, a suitable surface hydrophilic agent should be selected for spraying according to the different surface materials of the wafer.

[0023] By installing two spray pipes on the side of the polishing head, deionized water and surface hydrophilic agent are continuously rinsed alternately, so that the wafer is kept moist after the polishing head is raised and when it is transferred between platforms. Due to the hydrophobicity of bare silicon, it is not enough to moisturize the wafer with deionized water alone. At this time, the external environment is easy to introduce particles on the surface of the wafer, and it is difficult to clean in the subsequent process. Therefore, alternating rinsing with deionized water and surface hydrophilic agent can more effectively reduce the level of surface particles.

[0024] Attached Figure 3The figure shows a schematic diagram of the structure of the polishing head of the polishing equipment of another specific embodiment of the present invention. In this specific embodiment, a spraying device 23 is also included on the side of the polishing head 11, and the spraying device is arranged toward the polished wafer 14, and includes a first spray head 231 for spraying deionized water and a second spray head 232 for spraying a surface hydrophilic agent. The spraying device 22 is arranged to alternately spray deionized water and a surface hydrophilic agent to the polished wafer 14 when the polishing head 12 is in a raised state. In this specific embodiment, there are multiple first spray heads 231 for spraying deionized water and second spray heads 232 for spraying a surface hydrophilic agent, and they are alternately arranged around the polishing head to ensure uniformity of spraying.

[0025] Attached Figure 4 The figure is a schematic diagram of the steps of the polishing method described in a specific embodiment of the present invention, including: step S10, polishing the wafer; step S11, lifting the polishing head and transferring the wafer after polishing, and during the lifting and transferring process, using the first spray and the second spray head to alternately spray deionized water and a surface hydrophilic agent to the polished wafer.

[0026] In step S10, the wafer may be a wafer made of any common semiconductor material such as silicon, germanium, silicon carbide, GaAs, and GaN.

[0027] In step S11, the polished wafer 14 is a single crystal silicon wafer, and the corresponding surface hydrophilic agent is selected from one or a mixture of γ-aminopropyltriethoxysilane and polyoxyethylene chain, which can make the wafer surface hydrophilic. In other specific embodiments, a suitable surface hydrophilic agent should be selected according to the different surface materials of the wafer for spraying.

[0028] The above method installs two spray pipes on the side of the polishing head to continuously alternately rinse with deionized water and surface hydrophilic agent, so that the wafer is kept moist after the polishing head is raised and when it is transferred between platforms. Due to the hydrophobicity of bare silicon, it is not enough to moisturize the wafer with only deionized water. At this time, the external environment is easy to introduce particles on the surface of the wafer, and it is difficult to clean in the subsequent process. Therefore, alternating rinsing with deionized water and surface hydrophilic agent can more effectively reduce the level of surface particles.

[0029] The above is only a preferred embodiment of the present invention. It should be pointed out that ordinary technicians in this technical field can make several improvements and modifications without departing from the principle of the present invention. These improvements and modifications should also be regarded as the scope of protection of the present invention.

Claims

1. A polishing device, comprising a platform, a polishing pad and a polishing head, wherein the polishing pad is laid on the surface of the platform, the polishing head is in contact with the polishing pad, and a wafer to be polished is placed between the polishing head and the polishing pad, characterized in that: A spray device is also included on the side of the polishing head. The spray device is arranged toward the polished wafer and includes a first spray head for spraying deionized water and a second spray head for spraying a surface hydrophilic agent. The spray device is arranged to alternately spray deionized water and a surface hydrophilic agent onto the polished wafer when the polishing head is in a raised state.

2. The polishing device according to claim 1, characterized in that: There are multiple first nozzles; there are multiple second nozzles.

3. The polishing device according to claim 1, characterized in that: The first nozzle and the second nozzle are alternately arranged around the blasting head.

4. The polishing device according to claim 1, characterized in that: The first nozzle and the second nozzle extend to the side of the polishing head through a corrugated tube or a bamboo tube.

5. The polishing device according to claim 1, characterized in that: The surface hydrophilic agent is selected from one or a mixture of γ-aminopropyltriethoxysilane and polyoxyethylene chain.

6. A polishing method, characterized in that: include: Polishing the wafer; After polishing, the polishing head is lifted and the wafer is transferred. During the lifting and transferring process, the first spray head and the second spray head are used to alternately spray deionized water and a surface hydrophilic agent onto the polished wafer.

7. The polishing method according to claim 6, characterized in that: A plurality of first nozzles and a plurality of second nozzles are used.

8. The polishing method according to claim 6, characterized in that: The first nozzle and the second nozzle are alternately arranged around the blasting head.

9. The polishing method according to claim 6, characterized in that: The first nozzle and the second nozzle extend to the side of the polishing head through a corrugated tube or a bamboo tube.

10. The polishing method according to claim 6, characterized in that: The surface hydrophilic agent is selected from one of γ-aminopropyltriethoxysilane and polyoxyethylene chain or a mixture thereof.

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