Static elimination device and method for eliminating static electricity on wafer surface

Abstract

The present invention provides an electrostatic eliminator and a method for eliminating static electricity on a wafer surface. The electrostatic eliminator includes: an ion gun disposed on the periphery of the wafer, the ion gun being used to emit charged ions toward the wafer surface to neutralize the charge on the wafer surface; two magnetic field coils disposed above and below the wafer, respectively, the two magnetic field coils being used to generate a magnetic field toward the wafer, the magnetic field varying with the amount of charge on the wafer surface; and a charge detection unit connected to the magnetic field coil signals, the charge detection unit being used to detect the amount of charge on the wafer surface based on changes in the magnetic field. The technical solution of the present invention can eliminate charge accumulated on the wafer surface, thereby preventing damage to the wafer surface caused by electrostatic discharge.

Description

Technical Field

[0001] The present invention relates to the technical field of integrated circuit manufacturing applications, and in particular to a static elimination device and a method for eliminating static electricity on a wafer surface. Background Art

[0002] During the wafer production process, electric charges will form on the surface of the wafer due to various reasons such as electron microscope measurement, flushing and friction with ultrapure water and developer. If the charges cannot be discharged and accumulate on the surface of the wafer, when the charges accumulate to a certain amount, an electrostatic discharge effect will occur, thereby damaging the surface of the wafer.

[0003] like Figure 1 As shown, the traditional method of eliminating static electricity on the surface of the wafer is to continuously rinse the surface of the wafer 12 with deionized water 11 and then dry it. However, this method cannot completely eliminate the static electricity on the surface of the wafer 12, and there are still a lot of charges 121 remaining on the surface of the wafer 12.

[0004] Therefore, it is necessary to provide an electrostatic elimination device and a method for eliminating static electricity on the wafer surface to eliminate the charge accumulated on the wafer surface, thereby preventing electrostatic discharge from causing damage to the wafer surface. Summary of the Invention

[0005] The object of the present invention is to provide an electrostatic eliminator and a method for eliminating static electricity on the surface of a wafer, which can eliminate the charge accumulated on the surface of the wafer and thus avoid damage to the wafer surface caused by electrostatic discharge.

[0006] In order to solve the above technical problems, the present invention provides an electrostatic eliminator for eliminating charges accumulated on the surface of a wafer, the electrostatic eliminator comprising:

[0007] an ion gun, disposed on the periphery of the wafer, for emitting charged ions toward the surface of the wafer to neutralize the charge on the surface of the wafer;

[0008] Two magnetic field coils are respectively arranged above and below the wafer, and the two magnetic field coils are used to generate a magnetic field toward the wafer, and the magnetic field changes with the change of the charge on the surface of the wafer;

[0009] A charge detection unit is connected to the magnetic field coil signal, and the charge detection unit is used to detect the amount of charge on the surface of the wafer according to the change of the magnetic field.

[0010] Preferably, the static elimination device further comprises:

[0011] The static electricity removal chamber is used to place the wafer, the ion gun, the two magnetic field coils and the charge detection unit.

[0012] Preferably, the static elimination device further comprises:

[0013] A robotic arm is used to transfer the wafer and place it in the static-eliminating chamber, and to flip the wafer.

[0014] Preferably, the charge detection unit is connected to the ion gun signal so that the charge detection unit outputs the detection result of the charge amount to the ion gun, and the ion gun emits charged ions according to the detection result of the charge amount.

[0015] The present invention also provides a method for eliminating static electricity on the surface of a wafer, comprising:

[0016] Providing a wafer, wherein charges to be eliminated are accumulated on the surface of the wafer;

[0017] The static eliminator is used to eliminate the charge accumulated on the surface of the wafer; wherein, the ion gun is used to emit charged ions to the surface of the wafer to neutralize the charge on the surface of the wafer; and the charge detection unit is used to detect the amount of charge on the surface of the wafer according to the change of the magnetic field.

[0018] Preferably, the static elimination device further includes a static elimination chamber for placing the wafer, the ion gun, the two magnetic field coils and the charge detection unit.

[0019] Preferably, before placing the wafer in the static elimination chamber, the method for eliminating static electricity on the wafer surface further comprises:

[0020] Ultrapure water is used to clean the surface of the wafer.

[0021] Preferably, after cleaning the wafer surface with the ultrapure water, the method for eliminating static electricity on the wafer surface further comprises:

[0022] Drying the wafer surface

[0023] Preferably, a robotic arm is used to transfer the wafer and place it in the static elimination chamber, and a robotic arm is used to flip the wafer.

[0024] Preferably, the charge detection unit is connected to the ion gun signal, and the charge detection unit is used to output the detection result of the charge amount to the ion gun, so that the ion gun emits charged ions according to the detection result of the charge amount.

[0025] Compared with the prior art, the technical solution of the present invention has the following beneficial effects:

[0026] 1. The electrostatic eliminator of the present invention is used to eliminate the charges accumulated on the surface of the wafer. The electrostatic eliminator includes: an ion gun, which is arranged on the periphery of the wafer, and is used to emit charged ions to the surface of the wafer to neutralize the charges on the surface of the wafer; two magnetic field coils, which are respectively arranged above and below the wafer, and are used to generate a magnetic field toward the wafer, and the magnetic field changes with the change of the charge amount on the surface of the wafer; a charge detection unit, which is connected to the magnetic field coil signal, and is used to detect the charge amount on the surface of the wafer according to the change of the magnetic field, so that the charges accumulated on the surface of the wafer can be eliminated, thereby avoiding electrostatic discharge and causing damage to the wafer surface.

[0027] 2. The method for eliminating static electricity on the surface of a wafer of the present invention comprises: providing a wafer, on the surface of which charges to be eliminated are accumulated; using the static electricity elimination device to eliminate the charges accumulated on the surface of the wafer; wherein the ion gun is used to emit charged ions to the surface of the wafer to neutralize the charges on the surface of the wafer; and the charge detection unit is used to detect the amount of charge on the surface of the wafer according to the change of the magnetic field, so that the charges accumulated on the surface of the wafer can be eliminated, thereby avoiding damage to the wafer surface caused by electrostatic discharge. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Figure 1 This is a schematic diagram of the traditional method of eliminating static electricity on the wafer surface;

[0029] Figure 2 is a schematic diagram of a static elimination device according to an embodiment of the present invention;

[0030] Figure 3 The figure is a flow chart of a method for eliminating static electricity on a wafer surface according to an embodiment of the present invention.

[0031] Among them, Figure 1-Figure 3 The reference numerals are described as follows:

[0032] 11-deionized water; 12-wafer; 121-charge; 21-wafer; 22-ion gun; 23-charge detection unit; 24-magnetic field coil; 241-magnetic field. DETAILED DESCRIPTION

[0033] To make the purposes, advantages, and features of the present invention more clear, the static elimination device and the method for eliminating static electricity on the wafer surface proposed by the present invention are further described in detail below in conjunction with the accompanying drawings and specific embodiments. It should be noted that the drawings are all in a very simplified form and are not in precise proportions. They are only used to conveniently and clearly assist in explaining the purposes of the embodiments of the present invention. In addition, the structures shown in the drawings are often part of the actual structure. In particular, different drawings may need to show different focuses and sometimes use different proportions.

[0034] An embodiment of the present invention provides an electrostatic eliminator for eliminating charges accumulated on the surface of a wafer. The electrostatic eliminator includes: an ion gun, arranged on the periphery of the wafer, for emitting charged ions toward the surface of the wafer to neutralize the charges on the surface of the wafer; two magnetic field coils, respectively arranged above and below the wafer, for generating a magnetic field toward the wafer, the magnetic field changing with the change in the amount of charge on the surface of the wafer; and a charge detection unit, connected to the magnetic field coil signal, for detecting the amount of charge on the surface of the wafer according to the change in the magnetic field.

[0035] See below Figure 2 The static elimination device provided in this embodiment is introduced in detail.

[0036] During the process of producing the wafer 21, electric charges may be generated on the surface of the wafer 21 due to various reasons, such as measuring the wafer 21 with an electron microscope and flushing and rubbing the surface of the wafer 21 with ultrapure water and developer. If the electric charges cannot be discharged from the surface of the wafer 21 and accumulate on the surface of the wafer 21, when the electric charges accumulate to a certain amount, an electrostatic discharge effect will be generated, thereby damaging the surface of the wafer 21.

[0037] Therefore, the static eliminator provided in this embodiment is used to eliminate the charges accumulated on the surface of the wafer 21. The static eliminator includes an ion gun 22, two magnetic field coils 24 and a charge detection unit 23.

[0038] The ion gun 22 is arranged on the periphery of the wafer 21. The ion gun 22 is used to emit charged ions to the surface of the wafer 21. The charged ions emitted by the ion gun 22 have an electrical property opposite to the charge on the surface of the wafer 21, so that the charged ions neutralize the charge on the surface of the wafer 21.

[0039] Among them, it is preferred that the ion gun 22 is movably arranged on the periphery of the wafer 21, and by moving the ion gun 22 around the wafer 21, the ion gun 22 can emit charged ions around the entire edge of the wafer 21 toward the center of the wafer 21, so that each area on the surface of the wafer 21 can receive charged ions and the charged ions received by each area are more uniform, so that the charge on the surface of the wafer 21 can be neutralized more quickly and evenly; and, by moving the ion gun 22 up and down, the ion gun 22 can be adjusted to emit charged ions toward the front or back of the wafer 21; and, by moving and adjusting the angle between the ion gun 22 and the wafer 21, the outlet end of the ion gun 22 can be aligned with different areas on the front or back of the wafer 21, so that charged ions can be emitted separately to specific areas on the front or back of the wafer 21.

[0040] It should be noted that, in other embodiments, the ion gun 22 can be fixed, for example, the ion gun 22 is set horizontally, the wafer 21 is also set horizontally, the outlet end of the ion gun 22 faces the front or back of the wafer 21, and the wafer 21 is rotated so that each area on the front or back of the wafer 21 can receive the charged ions emitted by the ion gun 22. By flipping the wafer 21 (from the front facing up to the back facing up, or from the front facing down to the back facing down), the front and back of the wafer 21 can receive the charged ions emitted by the ion gun 22.

[0041] The two magnetic field coils 24 are respectively arranged above and below the wafer 21. The wafer 21 can be fixed between the two magnetic field coils 24 by using a clamping component (not shown). The two magnetic field coils 24 are used to generate a magnetic field 241 toward the wafer 21. When the ion gun 22 emits charged ions toward the surface of the wafer 21 so that the charge on the surface of the wafer 21 changes, the change in the charge on the surface of the wafer 21 will affect the magnetic field 241, so that the magnetic field 241 changes with the change in the charge on the surface of the wafer 21.

[0042] The charge detection unit 23 is signal-connected to the magnetic field coil 24 , and the signal of the change in the magnetic field 241 is transmitted to the charge detection unit 23 . The charge detection unit 23 is used to detect the amount of charge on the surface of the wafer 21 according to the change in the magnetic field 241 , and obtain the charge distribution of each area on the surface of the wafer 21 .

[0043] The static elimination device further includes a static elimination chamber (not shown), which is used to place the wafer 21 , the ion gun 22 , the two magnetic field coils 24 and the charge detection unit 23 .

[0044] In addition, the static elimination device also includes a robotic arm (not shown), which can be used to transfer the wafer 21 and place it in the static elimination chamber, and the robotic arm can be used to flip the wafer 21 during the process of using the ion gun 22 to emit charged ions to the surface of the wafer 21.

[0045] The static-elimination chamber is a sealed design. The wafer 21 can be transferred into the static-elimination chamber by the robotic arm. The robotic arm is flexible and can rotate, so the robotic arm can flip the wafer 21 within the static-elimination chamber. In addition, the insulating suction cup provided on the robotic arm can vacuum-adsorb the wafer 21. The insulating suction cup ensures that the robotic arm does not generate static electricity during the movement of the wafer 21, thereby not affecting the surface charge of the wafer 21.

[0046] Furthermore, the charge detection unit 23 is connected to the ion gun 22 signal so that the charge detection unit 23 outputs the detection result of the charge amount to the ion gun 22, and the ion gun 22 emits charged ions according to the detection result of the charge amount. In the static electricity removal chamber, when the signal of the change of the magnetic field 241 is transmitted to the charge detection unit 23 through the magnetic field coil 24, since the charge detection unit 23 is connected to the ion gun 22 signal, the charge detection unit 23 can synchronously transmit the charge amount detection result of the surface of the wafer 21 to the ion gun 22. The ion gun 22 is an automatic device. If the signal received by the ion gun 22 shows that there is charge accumulated on the surface of the wafer 21, the ion gun 22 will automatically emit charged ions to the surface of the wafer 21 for charge neutralization, thereby reducing the charge amount on the surface of the wafer 21; when the wafer 2 When the charge on the surface of the wafer 21 changes, the magnetic field 241 will be affected. The signal of the change in the magnetic field 241 is then transmitted to the charge detection unit 23. The charge detection unit 23 transmits the charge detection result on the surface of the wafer 21 to the ion gun 22. The ion gun 22 automatically emits charged ions onto the surface of the wafer 21 to neutralize the charge. The above steps are repeated until the charge detection unit 23 detects that the charge on the surface of the wafer 21 is within the set specifications (for example, the charge is 0), thereby eliminating the charge accumulated on the surface of the wafer 21 and avoiding damage to the surface of the wafer 21 caused by electrostatic discharge.

[0047] In summary, the present invention provides an electrostatic eliminator for eliminating charges accumulated on the surface of a wafer. The electrostatic eliminator comprises: an ion gun, disposed on the periphery of the wafer, for emitting charged ions toward the surface of the wafer to neutralize the charges on the surface of the wafer; two magnetic field coils, respectively disposed above and below the wafer, for generating a magnetic field toward the wafer, the magnetic field changing with the amount of charge on the surface of the wafer; a charge detection unit, connected to the magnetic field coil signal, for detecting the amount of charge on the surface of the wafer according to the change in the magnetic field. The electrostatic eliminator provided by the present invention can eliminate charges accumulated on the surface of the wafer, thereby avoiding damage to the wafer surface caused by electrostatic discharge.

[0048] An embodiment of the present invention further provides a method for eliminating static electricity on the surface of a wafer. Figure 3 , the method for eliminating static electricity on the wafer surface includes:

[0049] Step S1, providing a wafer, wherein charges to be eliminated are accumulated on the surface of the wafer;

[0050] Step S2, using the electrostatic eliminator to eliminate the charge accumulated on the surface of the wafer; wherein, the ion gun is used to emit charged ions to the surface of the wafer to neutralize the charge on the surface of the wafer; and, the charge detection unit is used to detect the amount of charge on the surface of the wafer according to the change of the magnetic field.

[0051] The method for eliminating static electricity on the wafer surface provided by this embodiment is described in detail in 2 below.

[0052] According to step S1 , a wafer 21 is provided, and charges to be eliminated are accumulated on the surface of the wafer 21 .

[0053] During the process of producing the wafer 21, electric charges may be generated on the surface of the wafer 21 due to various reasons, such as measuring the wafer 21 with an electron microscope and flushing and rubbing the surface of the wafer 21 with ultrapure water and developer. If the electric charges cannot be discharged from the surface of the wafer 21 and accumulate on the surface of the wafer 21, when the electric charges accumulate to a certain amount, an electrostatic discharge effect will be generated, thereby damaging the surface of the wafer 21.

[0054] According to step S2, the electrostatic eliminator is used to eliminate the charges accumulated on the surface of the wafer 21. In the process of eliminating the charges accumulated on the surface of the wafer 21, the ion gun 22 is used to emit charged ions to the surface of the wafer 21 to neutralize the charges on the surface of the wafer 21, and the charge detection unit 23 is used to detect the amount of charge on the surface of the wafer 21 in real time according to the changes in the magnetic field 241.

[0055] The electrostatic eliminator is described above and will not be described again here.

[0056] Preferably, the static elimination device further includes a static elimination chamber (not shown), and the ion gun 22 , the two magnetic field coils 24 and the charge detection unit 23 are disposed in the static elimination chamber.

[0057] Preferably, a robotic arm (not shown) is used to transfer and place the wafer 21 into the static elimination chamber, and the robotic arm is used to flip the wafer 21. Furthermore, since the insulating suction cup provided on the robotic arm can vacuum-absorb the wafer 21, the insulating suction cup ensures that the robotic arm does not generate static electricity during the process of moving the wafer 21, thereby not affecting the surface charge of the wafer 21.

[0058] Preferably, before placing the wafer 21 in the static elimination chamber, the method for eliminating static electricity on the wafer surface further comprises: using ultrapure water to clean the surface of the wafer 21. Cleaning the surface of the wafer 21 with ultrapure water can effectively remove impurities and foreign matter on the surface of the wafer 21.

[0059] Furthermore, after cleaning the surface of the wafer 21 with the ultrapure water and before placing the wafer 21 in the static elimination chamber, the method for eliminating static electricity on the wafer surface further includes drying the surface of the wafer 21. The drying method may be hot plate drying. By first cleaning the surface of the wafer 21 with ultrapure water and then drying it, the amount of partial charge on the surface of the wafer 21 can be effectively reduced.

[0060] Furthermore, the charge detection unit 23 is connected to the ion gun 22 signal so that the charge detection unit 23 outputs the detection result of the charge amount to the ion gun 22, and the ion gun 22 emits charged ions according to the detection result of the charge amount. In the static electricity removal chamber, when the signal of the change of the magnetic field 241 is transmitted to the charge detection unit 23 through the magnetic field coil 24, since the charge detection unit 23 is connected to the ion gun 22 signal, the charge detection unit 23 can synchronously transmit the charge amount detection result of the surface of the wafer 21 to the ion gun 22. The ion gun 22 is an automatic device. If the signal received by the ion gun 22 shows that there is charge accumulated on the surface of the wafer 21, the ion gun 22 will automatically emit charged ions to the surface of the wafer 21 for charge neutralization, thereby reducing the charge amount on the surface of the wafer 21; when the wafer 2 When the charge on the surface of the wafer 21 changes, the magnetic field 241 will be affected. The signal of the change in the magnetic field 241 is then transmitted to the charge detection unit 23. The charge detection unit 23 transmits the charge detection result on the surface of the wafer 21 to the ion gun 22. The ion gun 22 automatically emits charged ions onto the surface of the wafer 21 to neutralize the charge. The above steps are repeated until the charge detection unit 23 detects that the charge on the surface of the wafer 21 is within the set specifications (for example, the charge is 0), thereby eliminating the charge accumulated on the surface of the wafer 21 and avoiding damage to the surface of the wafer 21 caused by electrostatic discharge.

[0061] In summary, the method for eliminating static electricity on a wafer surface provided by the present invention includes: providing a wafer, the surface of which has accumulated charges to be eliminated; using the static electricity elimination device described above to eliminate the charges accumulated on the surface of the wafer; wherein the ion gun is used to emit charged ions toward the surface of the wafer to neutralize the charges on the surface of the wafer; and the charge detection unit is used to detect the amount of charge on the surface of the wafer based on changes in the magnetic field. The method for eliminating static electricity on a wafer surface provided by the present invention can eliminate the charges accumulated on the surface of the wafer, thereby preventing damage to the wafer surface caused by electrostatic discharge.

[0062] The above description is only a description of the preferred embodiments of the present invention and does not limit the scope of the present invention. Any changes and modifications made by ordinary technicians in the field of the present invention based on the above disclosure shall fall within the scope of protection of the claims.

Claims

1. An electrostatic eliminator for eliminating charges accumulated on the surface of a wafer, characterized in that: include: an ion gun, disposed on the periphery of the wafer, and movably disposed around the periphery of the wafer, or fixed; The ion gun is used to emit charged ions toward the surface of the wafer, wherein the charged ions emitted by the ion gun have an electrical property opposite to that of the charge on the surface of the wafer, so as to neutralize the charge on the surface of the wafer; Two magnetic field coils are respectively arranged above and below the wafer, and the two magnetic field coils are used to generate a magnetic field toward the wafer, and the magnetic field changes with the change of the charge on the surface of the wafer; A charge detection unit is connected to the magnetic field coil signal, and the charge detection unit is used to detect the amount of charge on the surface of the wafer according to the change of the magnetic field.

2. The static eliminator according to claim 1, wherein: The static elimination device further comprises: The static electricity removal chamber is used to place the wafer, the ion gun, the two magnetic field coils and the charge detection unit.

3. The static eliminator according to claim 2, wherein: The static elimination device further comprises: A robotic arm is used to transfer the wafer and place it in the static-eliminating chamber, and to flip the wafer.

4. The static eliminator according to claim 1, wherein The charge detection unit is connected to the ion gun signal so that the charge detection unit outputs the detection result of the charge amount to the ion gun, and the ion gun emits charged ions according to the detection result of the charge amount.

5. A method for eliminating static electricity on the surface of a wafer, characterized in that: include: Providing a wafer, wherein charges to be eliminated are accumulated on the surface of the wafer; The electrostatic eliminator as described in claim 1 is used to eliminate the charge accumulated on the surface of the wafer; wherein, the ion gun is used to emit charged ions to the surface of the wafer to neutralize the charge on the surface of the wafer; and the charge detection unit is used to detect the amount of charge on the surface of the wafer according to the change of the magnetic field.

6. The method for eliminating static electricity on the wafer surface according to claim 5, wherein: The static elimination device further includes a static elimination chamber for placing the wafer, the ion gun, the two magnetic field coils and the charge detection unit.

7. The method for eliminating static electricity on the wafer surface according to claim 6, wherein: Before placing the wafer in the static elimination chamber, the method for eliminating static electricity on the wafer surface further includes: Ultrapure water is used to clean the surface of the wafer.

8. The method for eliminating static electricity on the wafer surface according to claim 7, wherein: After cleaning the wafer surface with the ultrapure water, the method for eliminating static electricity on the wafer surface further includes: The surface of the wafer is dried.

9. The method for eliminating static electricity on the wafer surface according to claim 6, wherein: The wafer is transferred and placed in the static-eliminating chamber by a robotic arm, and the wafer is flipped by a robotic arm.

10. The method for eliminating static electricity on the wafer surface according to claim 5, wherein: The charge detection unit is connected to the ion gun signal, and the charge detection unit is used to output the detection result of the charge amount to the ion gun, so that the ion gun emits charged ions according to the detection result of the charge amount.

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