TW556305B - Wafer holder protecting wafer against electrostatic breakdown - Google Patents

Abstract

A wafer holder includes a mounting plate for mounting a wafer and having a plurality of fluid holes, a decompressor for absorbing the wafer toward the mounting plate while sucking air between the mounting plate and the wafer through the fluid holes, and a liquid supply unit for supplying a liquid toward the wafer to release the wafer from the wafer holder. The liquid has a specific resistance lower than the specific resistance of water.

Description

556305 V. Description of the Invention (1) [Field of the Invention] The present invention relates to a wafer holder for protecting the wafer from electrostatic damage, and particularly relates to a wafer holder for transferring wafers from a production line to :: machines such as Passed to a grinding device. [Previous technology] There are multiple semiconductor devices on the wafer. When the surface of the wafer is to be half-set and the body is charged with a small element, the electrostatic force of the charge will affect the interconnection between the semiconductor device and the wafer. Or affect the shape of the barrier layer. / For example, patents jp-A-6-123924 and jp-A-U-289004 disclose a holder for transferring wafers from a production line to a polishing device. In the holder disclosed in the patent JP-A-6-123924, a release device or a release element provides a suction force of a positive pressure gas between the wafer holder and the wafer, and the release wafer is used, wherein the above-mentioned positive pressure gas is Ionized gas. The ionized gas counteracts the static electricity that comes into contact with the wafer. The holder disclosed in the patent JP-A-1 1 -289004, a release element provides a gas for supplying or mixing water between the holder and the wafer to release the wafer from the holder. In this way, the polarity of the water offsets the charge remaining on the surface of the holder and the wafer. After studying the above-mentioned disclosed bracket, it was found that the electrostatic damage of the wafer may be due to the friction between the wafer bracket and the wafer, which caused static electricity on the wafer. In more detail, whether it is the ionized gas used in the patent jp_A — 6 — 1 23 9 24 or the water used in the patent JP-A-Π-289004, it has a large resistivity and cannot be used. Completely deplete static electricity so wafers are not exposed to static electricity

2133-5160-PF (N); Cat.ptd 556305 V. Destruction of Invention (2). [Summary of the Invention Therefore, the object of the present invention is a stent, which can effectively protect a wafer from detachment from a wafer holder. A protective cover according to the present invention includes: a metal plate support for placing holes formed on the metal plate support; fluid flow holes communicating for suction and a liquid supply unit for selectively supplying liquid through the body flow holes, the above-mentioned essence The embodiment further provides a method for facilitating the processing of a wafer, including the following air being held through a fluid flow hole; and when a liquid is supplied, the wafer is detached from the wafer holder wafer by the metal plate holder according to the present invention. The resistivity can effectively protect the static electricity from damage, because the static electricity on the lower resistance comes from this static electricity. In order to make the above of the present invention easy to understand, several specific examples are provided below to provide a wafer for supporting wafers without electrostatic damage, especially when the wafer is electrostatically damaged in a wafer holder. Wafer; at least one fluid is circulated and a fluid discharge unit is selectively connected to the liquid discharged from the fluid circulation hole; and the fluid resistance is lower than the wafer by communicating with the fluid circulation hole. Steps of using a metal holder with a fluid flow hole: When the wafer and the metal plate holder are withdrawn, the resistance of the wafer being absorbed by the metal plate holder is lower than that of the wafer. The small components on the circle are protected from the liquid of the coefficient. The wafer can be effectively removed from the wafer holder to produce other purposes, features and advantages. The preferred embodiment can be more obvious.

556305 V. Description of the invention (3) Detailed explanation [Implementation mode] The following describes the various embodiments and contents disclosed in the present invention in detail with specific embodiments. According to an embodiment of the present invention, the wafer holder is suitable for a chemical mechanical polishing (CMP) device. This chemical mechanical polishing device receives wafers from a production line via a wafer holder, aligns the wafers on the center of the polishing head, and then grinds the wafers. The wafer holder is used to suck the wafer placed thereon, and use the liquid to detach the wafer from the sucked state. In one embodiment of the present invention, when the wafer is placed on the metal plate holder of the wafer holder by the robot arm, the fluid discharge mechanism is selected to communicate with the fluid flow hole to suck the wafer, which uses the fluid flow hole The wafer is sucked by the air near the wafer holder, and the air is discharged by the fluid discharge mechanism. The wafer holder then releases the wafer from the suction state. At this time, the wafer is at the center of the chemical mechanical polishing device. At this stage, the liquid supply unit is selected to communicate with the fluid flow hole, and the wafer on the metal plate holder is supplied with liquid through the fluid flow hole. Therefore, the wafer is detached from the metal plate holder and floats on the metal plate holder above the liquid. The liquid supply unit prepares liquid in the mixer with a resistivity lower than that of water. The liquid is supplied to the fluid flow hole by a regulator, and the liquid has a predetermined pressure and a predetermined flow rate. The fluid flow hole is from the back of the wafer holder

2133-5160-PF (N); Cat.ptd p. 7 556305

The surface provides liquid to the surface of the wafer. Because the resistivity of the liquid provided by the fluid flow hole is lower than that of water, the micro-components on the wafer can be protected by this liquid to prevent electrostatic damage. 2 The resistivity of the liquid is preferably equal to or less than 0.5M Ω-cm. The micro-elements on Lai Jing have almost no electric field due to static electricity and are not affected by the pressure or flow rate of the fluid supplied by the through-hole. ~ Liquid carbon dioxide or ammonia with a resistivity lower than water is a more suitable body. Carbon dioxide has less impact on human health and requires special equipment to control it during processing. Ammonia also requires less special control during processing. The reason why carbon dioxide is better is that it does not have a pungent odor. In one embodiment of the present invention, the table v ^ / 1, -i- ^ connected to the metal plate support has a plurality of fluid flow holes on the mouth surface, which has a low The resistivity liquid ^ is more suitable for protecting the tiny components on the wafer from being sentenced. Low-flow liquid will slow down the movement speed of the wafer. This movement is caused by the liquid supplied from the fluid flow hole from the wafer. In this example, the supply of liquid at the fluid flow hole to the wafer drift 2 is started; the rack may take some time, otherwise the transfer of the wafer may fail due to the completion of the separation of the wafer from the wafer holder. He uses a regulator and a plurality of fluid flow holes to store liquids with a coefficient of resistance lower than water, and the static electricity on the charged wafer can be suppressed-several fluid flow holes 20 can reduce the flow rate of the liquid and provide suitable recovery. The wafer 12 is separated from the metal plate holder 18 at a suitable speed. The speed of the plurality of fluid flow holes 20 is arranged on the metal plate support 18 and the J

2133-5160-PF (N); Cat.ptd Page 8 556305 V. Description of the invention (5) Radius openings' are arranged on the metal plate support with a certain density. This setting allows the pressure of the liquid to be maintained Set the value and increase the speed at which the wafer 2 leaves the metal plate holder 18. Each fluid flow hole 20 has a funnel-shaped appearance and is located on the surface of the metal plate holder 18, so the liquid flow rate per unit area of the fluid flow hole 20 can be reduced, thereby suppressing the static electricity of the wafer 12. The wafer holder 10 of the present invention provides a plurality of nozzles 21, each of which has a plurality of fluid flow holes 20, and this setting can reduce the liquid flow rate per unit area on the wafer 2 to suppress the pressure on the wafer 2 Static electricity and increase the speed of the wafer 2 from the metal plate holder 18. The cradle 10 has a pure water supply unit 32 and a regulator 38 located downstream of the pure water supply unit 32 to control the pressure and flow rate of pure water. The cradle 10 can choose to be supplied with liquid or pure 3 2 by the liquid supply unit 30. Supply of pure water. When the liquid is supplied through the fluid circulation hole 20, the polishing head 16 of the chemical mechanical polishing (CMP) device is cleaned through the wafer holder 10. Although the liquid is narrow, the force and flow are released to the process towel of the wafer 12. It is controlled to protect the tiny elements on the wafer 12, but it does not need to be controlled when cleaning the polishing device. Furthermore, it is preferable to have a higher pressure and flow rate when cleaning the polishing head 16. Next, the present invention will cooperate with the drawings in more detail. FIG. ′ -Wafer holder 1Q ′ is used as a wafer in the production line during the process according to the invention. The head 16 is used. Do the right thing and do the wrong thing. A wafer 1 2 is transferred from the production line to the wafer holder 10 by a robotic arm.

2133-5160-PF (N); Cat.ptd Page 9 556305 V. Description of the invention (6) Positioned by the positioner 14 on the wafer holder 10, the grinding head 16 is lost and suspended and suspended by The vertical axis can be moved in the vertical direction as the center, and then transferred to the chemical mechanical polishing (CMP) device. The wafer holder 10 sucks and supports the wafer 12 and positions it on it, and then releases the wafer from the sucked state 1 2 The wafer j 2 is transferred between the production line and the chemical mechanical polishing (CMP) device. In the present embodiment, the main surface on which the minute elements are formed on the wafer 12 is the other side facing away from the wafer holder 10, and the bottom surface of the wafer 12 is opposite to the polishing head 16; however, the wafer The main surface and the bottom surface of 12 may also be opposite to the polishing head 16 and the wafer holder 10, respectively. A wafer support 10 includes a metal plate support 18 having a smooth upper surface. The upper surface of the metal plate support 18 has a plurality of fluid flow holes 20, and is communicated with a pipeline 22 through the lower surface of the metal plate support 18. The fluid flow hole 20 may be selectively communicated with the fluid discharge unit 28, the liquid supply unit 30, or the pure water supply unit 32 through a pipeline 22, a first selection valve 24, and a second selection valve 26. When the first selection valve 24 and the second selection valve 26 are both in the first position, the fluid circulation hole 20 is in communication with the fluid discharge unit 28, and when the first selection valve 24 and the first selection valve 26 are respectively When the first position and the second position are selected, the fluid flow hole 20 communicates with the pure water supply unit 32, and when the second selection valve 26 selects the second position, the fluid flow hole 20 communicates with the liquid supply unit 30 . The fluid discharge unit 28 has the function of sucking out the air above the metal plate support 18 through the fluid circulation hole 20. The fluid discharge unit 28 is in communication with a gas pressure reducer or vacuum pump to reduce the internal pressure of the fluid discharge unit 28. The fluid discharge unit 28 and the solid particles sucked out by the fluid discharge unit 28 are passed through a pressure reducer.

556305 V. Description of the invention (7) " ---- In addition to the system collected and discharged by the collection tank, in this embodiment, air, nitrogen or inert gas is selectively injected into the pipeline 22 through the third selection valve 34 in. Person # liquid supply unit 3 〇 includes a mixing device 36 and a regulator 3 8, mixing: Ling set 3 6 prepares liquid carbon dioxide with a specific concentration by dissolving slave dioxide in water to adjust, carbon dioxide can be replaced by other gases . The liquid carbon dioxide used in this embodiment has a conductivity of 0.5M cm or less, and liquid carbon dioxide with a conductivity of 0.5M Ω _ cm or less can effectively prevent the minute elements on the wafer 12 from being damaged by static electricity. It has nothing to do with the pressure and flow rate of the liquid injected through the fluid flow hole 20. The regulator 38 is disposed between the mixing device 36 and the first selection valve 24. The regulator 38 has a function of storing liquid carbon dioxide to be supplied to the mixing device 36, and supplying the stored liquid carbon dioxide to the fluid circulation hole 20 through a pipe 22 at a predetermined pressure and a predetermined flow rate. ^ The pure water supply unit 32 has the function of supplying pure water to the fluid circulation hole 20 through the pipeline 22 and the first selection valve 24 from a pure water storage tank (not shown in the figure). The pure water supply unit 32 is supplied through the pipeline 22 Pure water is used for grinding the grinding head 16. It must be noted here that the pure water supply unit 32 in this system contains another regulator, and the pressure and flow rate of the pure water are controlled by this regulator. According to FIG. 2, the surface of the metal plate holder 18 has a plurality of fluid flow holes 20. The cross-section of each fluid flow hole 20 is elongated and extends outward in the radial direction. The plurality of elongated fluid flow holes 2 〇 It is arranged on the surface of the metal plate holder 18 in four directions and is 90% with each other. . In the process of injecting liquid into the liquid supply unit 30 through the fluid circulation hole 20, in order to protect the tiny elements on the wafer 12 from electrostatic damage, the liquid

556305 V. Description of the invention (8) The pressure and flow rate of the body must be reduced. In this embodiment, the plurality of fluid flow holes 20 provided by the metal plate bracket 18 are used to stabilize the liquid through the fluid flow holes 2 0. The injection is directed to the wafer 12 so that the pressure and flow rate of the liquid can be reduced. The plurality of fluid flow holes 20 can ensure a certain flow rate to provide the speed required for the wafer 2 to escape from the metal plate holder 18. In order to reduce the pressure of the liquid in the opening of the fluid circulation hole 20, the opening of the fluid circulation hole 20 at the upper end of the fluid circulation hole 20 has a large cross-section. According to FIG. 3A, another embodiment of the metal plate holder 19 is used for the wafer holder 10 of FIG. 1. It has a plurality of nozzles 21, and the top surface of each nozzle 21 is connected to the metal plate holder 19. The surface is flush. According to FIG. 3B, each nozzle 21 has a plurality of fluid passage holes 20 'on the top of the nozzle 21, and each fluid passage hole 20 on each nozzle 21 is located at the bottom of the nozzle 21 and the i-th. The pipeline 22 in the figure is connected. When the liquid supply unit 30 supplies the liquid to the nozzle 21 through the pipeline 22, the liquid is supplied to the main surface of the wafer 12 at a lower flow rate through the respective fluid circulation holes 20. The fluid flow hole 20 is formed on the nozzle 21 to reduce the flow rate per unit area on the main surface of the wafer 12. Here, the flow rate toward the surface of the wafer 12 is reduced to suppress the static electricity of the wafer 12 without affecting The speed at which the wafer 12 is released from the metal plate holder j 8, so that the wafer 12 can be quickly transferred to the production station of the next process. The chemical mechanical polishing (CMP) device is held and released by the wafer holder 10 Wafer 1 2 status is clearly described in section! In the figure, after the wafer 12 is transferred to the production line by a chemical mechanical polishing (CMP) device, the positioner 14 is in a state of releasing the wafer 12, and the metal plate holder 18 is separated from the polishing head in a vertical direction.

556305 Description of the invention (9) The selection valve 24 and the second selection valve 26 are located at the initial positions, and the pipeline 22 is disconnected from the fluid discharge unit 28, the liquid supply unit 30, or the pure water supply unit 32. After the second selection valve 26 selects the second position and the first selection valve 24 selects the first position, the pure water supply unit 32 communicates with the fluid circulation hole 20 through the pipeline 22. In this state, the pure water supply unit 32 supplies one The relatively high-pressure liquid is injected into the grinding head 16 through the fluid flow hole 20 to quickly clean the grinding head 16 °. When the second selection valve 26 is turned to the first position, the pressure in the metal plate bracket 18 and the pure water supply path is reduced. The pure water remaining in the system will be discharged out of the metal plate bracket 18 and the pure water supply path. A plurality of fluid flow holes 20 are evenly formed on the metal plate support 丨 8, so that the pure water to be discharged can be smoothly discharged from the upper surface of the metal plate support 18, and the pure water stored in the pure water storage tank is finally the same. Way out. After a certain time, the second selector valve 26 returns to the initial position. Next, the robot arm places the next wafer 2 onto the metal plate holder 8 and the second selection valve 26 then selects the first position to communicate the fluid circulation hole 20 and the fluid discharge unit 28, and the metal plate holder 8 sucks The main surface of the wafer 2 is clamped on the metal plate holder 18. The first selection valve 24 selects the second position to communicate the pipeline 22 and the regulator 38, wherein the liquid supply unit 30 provides a liquid carbon dioxide of a predetermined pressure and flow rate, and the regulator 38 is injected into the fluid circulation hole 20, and the fluid circulation hole 20 Supply liquid carbon dioxide between the metal plate holders 8 and the wafers 2 to separate the metal plate holders 18 and the wafers 12.

556305 V. Description of the invention (ίο) Positioning Gong 1 4 Measure the position of wafer 1 2 and separate the metal plate holder 18 and the grinding head 1 6 'Second, the first selection valve 2 4 selects the first position to communicate with the fluid flow hole 20 And a fluid discharge unit 28 for discharging the liquid carbon dioxide from the metal plate holder 18 and the wafer 12 to the wafer 12 and therefore the main surface of the wafer 12 is sucked by the metal plate holder 18 and then the positioner 1 4 release the wafer 1 2. After that, the metal plate holder 18 rises, and the bottom of the grinding head 6 is provided with a film or a separator and is unfolded to the metal plate holder 18. As the metal plate holder 8 rises, the wafer 12 and the grinding head 16 are raised. The unrolled film comes into contact. Secondly, the polishing head 16 suspends the wafer 12 in a sucking manner. When the polishing head 16 sucks the wafer 12, the first selection valve 24 is located at the second position at the same time. Liquid carbon dioxide is injected through the fluid circulation hole 20 to release the wafer 1 2 ′ sucked by the metal plate holder 丨 8, and thus the wafer 12 is transferred from the metal plate holder 18 to the polishing head 16. Next, the grinding head 16 rotates and grinds the wafer 12. After the wafer 12 is ground by the grinding head 16, the grinding head 16 returns the wafer 12 to the metal plate holder 18, and when the grinding head 16 The thin film is unfolded, and the metal plate support 8 is also raised at the same time. The first selection valve 2 6 selects the first position to communicate with the fluid flow hole 20 and the fluid discharge unit 28. The metal plate holder 18 sucks the wafer 1 2 and then descends. The polishing head 16 stops unfolding the film and Began to shrink the film. When the liquid carbon dioxide stored in the regulator 38 is injected into the fluid flow hole 20 at a predetermined pressure and flow rate, the first selection valve 24 selects the second position. Liquid carbon dioxide is injected between the metal plate holder 18 and the wafer j 2 through the fluid circulation hole 20, and the wafer 12 is separated from the metal plate holder 18 at this time. Next, the positioner 14 starts to position the wafer 1 2 away from the metal plate holder 18 relative to the grinding head 16, and the first selection valve 24 selects the first position to communicate with the flow.

2133-5160-PF (N); Cat.ptd p. 14 556305 and the surface of the fluid exhaust oxidation obstacle, positioning the robot arm step, the first position to the grinding process frame 18 to the pure step, the pure invention has been invented, Within the encirclement, you should still attach the fifth, invention description (π) to the liquid crystal circle 1 2 of the main flow meter between the bottom of the main watch's last line, at this step position and the second 32, the wafer 1 2 and Metal plate support circle 12 2 step out Although the original is used to limit the spirit and scope of the protection scope out of the unit 28, the wafer 1 2 and the device 14 are released. After the wafer 12 is connected to the fluid flow sequence by a selection valve 24 It is better to be separated from ground water and free of water. How to familiarize yourself with this patent application? The metal plate is made of metal wafer 12. The metal plate support, the second selection hole 20, and the grinding fluid contact the static electricity to break the carbon monoxide. The example was revealed by the artist, and he changed and extended the range of the bracket 1 8 and the wafer 1 2 The plate holder 1 8 Hold the crystal frame 18 8 The first pure water supply unit is selected up to the production selection valve 26, so that the wafer 1 2 is broken, however, it is replaced in the crystal. As above, however, it does not depart from the present invention, so the present invention will prevail.

556305 Brief Description of Drawings Figure 1 is a schematic diagram showing a wafer holder for protecting the wafer from electrostatic damage according to the present invention. Figure 2 shows an enlarged view of the metal plate holder in Figure 1, where the wafers are shown with dashed lines. Figure 3A shows another type of metal plate support. Figure 3B is an enlarged view of the nozzle in Figure 3A. Explanation of symbols] 1 2 to wafer 16 to polishing head 2 0 to fluid flow hole 2 1 to nozzle 24 to first selection valve 28 to fluid discharge unit 3 2 to pure water supply unit 3 6 to mixing device 1 0 to crystal Round bracket 1 4 to positioner 18, 19 to metal plate bracket 2 0 '~ fluid flow hole 22 to pipeline 2 6 to second selection valve 3 0 to liquid supply unit 34 to third selection valve 3 8 to regulator

2133-5160-PF (N); Cat.ptd p. 16

Claims (1)

556305 6. Scope of patent application 1. A wafer holder for protecting the wafer from electrostatic damage, comprising: a metal plate holder for placing a wafer; at least one fluid circulation hole formed on the metal plate holder; a fluid discharge A unit selectively communicating with the fluid circulation hole for sucking liquid discharged from the fluid circulation hole; and a liquid supply unit selectively communicating with the fluid circulation hole and supplying a liquid through the fluid circulation hole, The resistivity of the liquid is lower than that of the wafer. 2. The wafer holder for protecting the wafer from electrostatic damage according to item 1 of the scope of the patent application, wherein the liquid supply unit includes a regulator to control the pressure and flow rate of the liquid before the liquid passes through the fluid flow hole. 3. The wafer holder for protecting the wafer from electrostatic damage as described in item 1 of the scope of the patent application, wherein the liquid has a conductivity coefficient of 0.5 M Ω -cm or less. 4 · The wafer holder for protecting the wafer from electrostatic damage as described in item 1 of the scope of the patent application, wherein the liquid is formed by dissolving carbon dioxide in water. 5. The wafer holder for protecting the wafer from electrostatic damage as described in item 1 of the scope of the patent application, wherein the liquid includes ammonia and water. 6. The wafer holder for protecting the wafer from electrostatic damage according to item 1 of the scope of the patent application, wherein the at least one fluid circulation hole includes a plurality of fluid passages L. 7. The wafer holder for protecting the wafer from electrostatic damage as described in item 1 of the scope of the patent application, wherein the cross-sectional area of the fluid flow hole at the outlet is larger than the cross-sectional area of the metal plate holder. 2133-5160-PF (N); Cat.ptd p. 17 556305 a 'Application for pastes'. Said 8 · Protection against electrostatic damage to wafers as described in item 丨 of patent application scope = Round bracket, where the metal plate bracket Including a plurality of nozzles, each of which has a plurality of fluid flow holes. , The bird said. 9. The round wafer bracket for protecting wafers from electrostatic damage as described in item 丨 of the scope of patent application, which further includes a water supply unit for supplying pure water, gas and the pure water through the fluid in an optional manner. Hole provided. / 成 1 〇. A method for processing a wafer using a metal holder with a fluid flow hole, including the following steps: When the air between the wafer and the metal plate holder is withdrawn through the fluid flow 1 hole, the crystal The circle is sucked by the metal plate holder; and k, when a liquid is supplied, the resistivity of which is lower than that of water, the wafer is detached from the metal plate holder. 1 1. The method for processing a wafer by using a metal holder having a fluid flow hole as described in item 10 of the scope of the patent application, wherein the liquid has a conductivity of 0.1 μm or less. 1 2. The method for processing a wafer using a metal holder having a fluid flow hole as described in item 10 of the scope of the patent application, further comprising a step of supplying pure water through the fluid flow hole. '' '1 3 ·-A method for chemical mechanical polishing of wafers' Using a polishing head and a metal plate holder connected to it and having a fluid flow hole' includes the following steps: When the air between the wafer and the metal plate holder passes When the fluid flow hole is withdrawn, the wafer is sucked by the metal plate support; when a liquid is supplied, and its resistivity is lower than that of water, the wafer is detached from the metal plate support; and 556305 6. Scope of patent application Pure water is provided through the fluid circulation hole to clean the grinding head. 2133-5160-PF (N); Cat.ptd p. 19