Substrate holding device, exposure device, semiconductor processing device, and method for peeling substrate

Abstract

To provide a substrate holding mechanism capable of appropriately peeling various substrates different in size, thickness, for example, from a table.SOLUTION: A substrate holding device 10 includes: a table 20 capable of vacuum suction; a lifting mechanism 30 provided with lifters 32 and 34; and exhaust devices 42 and 44. Each of the lifters 32 and 34 has a holding surface for holding a peripheral portion of a substrate W and is provided with a plurality of outlets for supplying gas between the substrate W and the table 20. With release of vacuum suction, gas is blown out from a suction hole 20P of the table 20, and gas is sent out from the outlets of the lifters 32 and 34, whereby gas is supplied to the back surface of the substrate W from the peripheral side of the substrate.SELECTED DRAWING: Figure 4

Description

[Technical Field]

[0001] The present invention relates to a substrate holding device for holding a substrate such as a semiconductor wafer, and more particularly to a suction mechanism for suctioning a substrate onto a holding surface by vacuum suction. [Background technology]

[0002] Various semiconductor processing apparatuses used in semiconductor manufacturing processes, such as exposure apparatuses, film deposition apparatuses, etching apparatuses, and polishing apparatuses, are equipped with a mechanism for fixing a substrate carried into the apparatus on a substrate mounting table. For example, in a projection exposure apparatus, a vacuum chuck is provided on the table on which the substrate is mounted, and the substrate is attracted to and fixed to the table by vacuum suction. When the exposure process for the substrate is completed, the substrate is detached from the table by ejecting gas such as air from the table and is then transported out of the apparatus (see, for example, Patent Documents 1 and 2).

[0003] When removing a semiconductor wafer from a table, the substrate is prone to deformation and damage. To prevent this, for example, a suction pad with concentric chuck grooves (pad pieces) is attached to the table, and a flow path is formed between the substrate and the table, allowing for vacuum suction (see Patent Document 3). A suction hole near the center of the table is selectively connected to a vacuum source or a gas supply source, allowing for switching between exhaust and intake. During a specific process, such as polishing, the substrate is fixed to the table by vacuum suction, and when the process is completed, pressurized air is sent out from the table surface through the vacuum forming hole. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Laid-Open No. 2012-146710 [Patent Document 2] Japanese Patent Application Laid-Open No. 2015-200910 [Patent Document 3] Japanese Patent Application Laid-Open No. 2010-153585 Summary of the Invention [Problem to be solved by the invention]

[0005] In recent years, semiconductor wafers have become thinner and larger in diameter. For semiconductor wafers made of brittle materials, in order to peel and release the substrate from the table without deforming or damaging it, compressed air must be evenly delivered from the backside of the semiconductor wafer. However, there are limitations on the number and location of suction holes provided on the table of the substrate holding device.

[0006] Therefore, it is necessary to provide a substrate holding mechanism that can appropriately release various substrates of different sizes, thicknesses, etc. from the table. [Means for solving the problem]

[0007] The substrate holding device of the present invention can be configured as a substrate holding device that can be incorporated into or operate in cooperation with an exposure device such as a contact exposure device, a maskless exposure device, or a projection exposure device, or can be configured as a substrate holding device that can be incorporated into or operate in cooperation with a semiconductor processing device such as a polishing device, an etching device, or a film forming device.

[0008] The substrate holding device of the present invention includes a table having a holding surface capable of adsorbing a substrate, and a lifting mechanism capable of holding the outer edge portion of the substrate and lifting the substrate from the table. Here, the "outer edge portion of the substrate" refers to any portion that can be held from the periphery (outside) of the substrate, and the area of ​​the outer edge portion can be determined according to the size and thickness of the substrate, the configuration of the holding mechanism, etc.

[0009] The substrate holding device of the present invention includes a gas supply unit that can supply gas from the peripheral (outer) edge side of the substrate between the table and the back surface of the substrate placed on the table or lifted by the lifting mechanism.

[0010] There are various configurations for adsorbing and releasing a substrate onto and from the holding surface of the table. For example, the table can be configured to have suction holes that selectively connect between a vacuum source and a gas supply source. The substrate can be adsorbed by connecting the vacuum source to the suction holes, and the substrate can be released from the holding surface by connecting the gas supply source to the suction holes.

[0011] The gas supply unit may have a variety of gas supplying methods and configurations. For example, it may include a gas supply source, a gas flow path such as a pipe, and a gas outlet (such as a suction hole). The term "gas supply unit" as used herein also includes a configuration in which a gas supply source for the gas supply unit is separately provided, and a flow path such as a pipe and an outlet, or only an outlet, is provided. For example, the gas supply unit may be capable of sending gas from multiple directions toward the center of the substrate, and may be configured with multiple outlets around the periphery of the substrate.

[0012] The lifting mechanism may also be configured in various ways. For example, the lifting mechanism may include at least one lifter that can be raised from the table surface. By configuring the lifter to have an outlet, the gas supply unit can supply gas from the outlet provided in the lifter. The lifter may be configured to peel and release the substrate, and then descend after holding the next substrate.

[0013] It is possible to provide multiple lifters. By providing an outlet in each lifter, it is possible to supply gas from the gas supply unit from various directions around the substrate toward the center. Furthermore, when multiple lifters are provided, it is possible to appropriately determine the outlets, i.e., the outflow direction. For example, multiple lifters can be arranged symmetrically with respect to the center of the table.

[0014] The lifter may be configured to have a suction holding function. For example, the lifter may be configured to have a holding surface that can suction the peripheral edge of the substrate. The lifter may also have an outlet below the holding surface. The gas supply unit can supply gas from the outlet provided below the holding surface.

[0015] When an outlet is provided in the lifter, there are various ways of supplying gas. It is possible to supply gas in accordance with the movement of the substrate on the table. For example, if the table has a suction hole that selectively connects between a vacuum source and a gas supply source, the gas supply unit can supply gas from the gas supply source through the outlet in accordance with the movement of the lifter up and down, the movement of the substrate to be removed, etc.

[0016] The placement of the suction holes in the table can vary: for example, if the table has suction holes that selectively connect between a vacuum source and a gas source, the suction holes can be located asymmetrically relative to the center of the table.

[0017] For example, the table may have a disk-shaped suction pad with concentric chuck grooves and at least one through groove extending radially, and the through groove may be formed between the periphery and center of the suction pad so as to intersect with a portion of the chuck groove.

[0018] There are various ways to form the through grooves. For example, multiple through grooves can be formed as linear grooves that are not aligned in a straight line but point in different directions. For example, the length of the through grooves can be set to 1 / 3 or less of the table width.

[0019] Furthermore, one through groove or multiple through grooves may be formed between the outermost and innermost circumferential grooves, and the outermost and innermost circumferential grooves do not intersect with the through grooves.

[0020] The through groove having such characteristics can be configured with a structure other than the lifting mechanism with the lifter described above. Also, it is possible to have only a suction mechanism for the table, and not to provide a structure for supplying gas from the peripheral edge side of the substrate.

[0021] For example, the substrate holding device may include a table having a disk-shaped suction pad capable of suctioning a substrate and having concentric chuck grooves and at least one radially extending through-groove, and a lifting mechanism capable of holding the outer edge of the substrate and lifting the substrate from the table, the through-groove intersecting a portion of the chuck groove between the periphery and center of the suction pad. For example, one through-groove or multiple through-grooves may be formed between the outermost and innermost circumferential grooves. The outermost and innermost circumferential grooves do not intersect with the through-groove.

[0022] Alternatively, in another aspect, the substrate holding device comprises the table and the lifting mechanism, and the multiple through grooves are offset so as not to be aligned in a straight line, and are formed as linear grooves facing in different directions. [Effects of the Invention]

[0023] According to the present invention, it is possible to provide a substrate holding mechanism that can appropriately release various substrates of different sizes, thicknesses, etc. from a table. [Brief explanation of the drawings]

[0024] [Figure 1] FIG. 1 is a diagram schematically illustrating a part of an exposure apparatus according to an embodiment of the present invention. [Figure 2] FIG. 2 is a schematic plan view of a table and a lifter viewed from above. [Figure 3] FIG. [Figure 4] FIG. 10 is a diagram schematically illustrating a state in which the substrate is peeled off. [Figure 5] FIG. 10 is a diagram showing a modified example of the substrate holding device of the present embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0025] Hereinafter, a substrate holding device according to this embodiment and an exposure apparatus including the same will be described with reference to the drawings.

[0026] FIG. 1 is a diagram showing a schematic view of a part of the exposure apparatus according to the present embodiment.

[0027] Here, exposure apparatus 100 is configured as a projection optical exposure apparatus. Exposure apparatus 100 includes a mask 110, a projection optical system 120, and a substrate holding device 10, and light from a light source (not shown) passes through mask 110 and is projected onto substrate W.

[0028] The substrate W here is configured as a thin semiconductor wafer. For example, an ultra-thin wafer called a TAIKO wafer, which has back grinding (BG tape) on the back surface of the substrate, can be used as the substrate W. It is also possible to use a substrate-type thin semiconductor wafer.

[0029] The substrate holding device 10 includes a table 20 on which the substrate W is placed. The table 20 functions as a wafer chuck (vacuum chuck) that can adsorb and fix the substrate W by vacuum suction, and suction holes (not shown here) for vacuum suction and compressed air supply are formed in the surface of the table 20, and suction pads 22 are also installed on the table 20. The table 20 can be moved in the horizontal direction (XY directions) by a stage movement mechanism (not shown).

[0030] The suction holes provided in the table 20 are connected to the exhaust devices 42 and 44 via flow paths 52 and 53, respectively. The control unit 50 controls the exhaust devices 42 and 44 to selectively connect the suction holes to a vacuum source or a gas supply source (not shown).

[0031] The lifting mechanism 30 capable of lifting the substrate W includes lifters 32 and 34. It holds the peripheral edge (outer edge) portion of the substrate W and can move the substrate W up and down in the vertical direction (Z direction) to a predetermined height from the table 20. The control unit 50 controls the actuators 56 and 58 to move the lifters 32 and 34 in the vertical direction.

[0032] When exposure is performed, the substrate W is transported to the substrate holding device 10 by the transport robot 140. Then, the lifters 32, 34 are raised and lowered to place the substrate W on the table 20. Once placed on the table 20, the substrate W is adsorbed to the table 20 by vacuum suction. Thereafter, an exposure operation is performed in which pattern light is projected onto the substrate W.

[0033] When the exposure operation is completed, the vacuum suction is released (vacuum breaking). Specifically, the exhaust devices 42, 44 connect the suction holes to the gas supply source, and compressed air is supplied through the suction holes to the backside of the substrate W. In response to this, the lifters 32, 34 rise, lifting the substrate W upward.

[0034] The negative pressure on the backside of the substrate W is released by supplying compressed air to the backside of the substrate W. As a result, the substrate W is separated from the table 20 and lifted by the lifters 32 and 34. The transport robot 140 receives the lifted substrate W and transports it to an apparatus for performing the next process.

[0035] In this embodiment, the lifters 32, 34 are configured as lift chucks having a substrate suction function. The lifters 32, 34 also have a separation function of blowing gas from the peripheral edge (outside) of the substrate W toward the center when peeling the substrate W from the table 20 and removing it from the table 20. When peeling the substrate W from the table 20, the exhaust devices 42, 44 blow pressurized air between the substrate W and the table 20 through outlets (not shown here) provided in the lifters 32, 34.

[0036] 2 is a schematic plan view of the table 20 and the lifters 32 and 34 as viewed from above. FIG. 3 is a perspective view of the lifter 32.

[0037] Table 20 is formed in a disk shape, with recesses 20R1 and 20R2 formed at opposing positions. Lifters 32 and 34, which are fan-shaped when viewed from above, are arranged to match the positions of recesses 20R1 and 20R2. Lifters 32 and 34 are arranged symmetrically with respect to center C of table 20, and their configurations, including their external shapes, are substantially the same.

[0038] The suction pad 22 placed on the surface of the table 20 has minute chuck grooves (see symbol R1) formed concentrically over the entire surface so that the suction force generated by vacuum drawing can be applied over the entire surface of the substrate W. In addition, the suction pad 22 has linear through grooves R2 formed in the radial direction to connect the chuck grooves R1.

[0039] The through groove R2 is formed so as to partially intersect the chuck groove R1 along the radial direction of the table 20. In other words, the through groove R2 does not extend from the center C of the table 20 to the peripheral edge 20E, and is not formed so as to intersect all of the concentric chuck grooves R1.

[0040] A plurality of suction holes 20P for vacuum suction and compressed air supply are formed in the table 20 in accordance with the positions of the through groove R2. Because the through groove R2 is formed in a position asymmetrical with respect to the center C of the table 20, the plurality of suction holes P along the through groove R2 are asymmetrical with respect to the center C.

[0041] 3, the lifter 32 has slit-shaped suction holes 32K1 and 32K2 formed in a holding surface 32S for holding the substrate W. The positions of the lifters 32 and 34 are controlled in the vertical direction so that the holding surface 32S for holding the substrate W coincides with the surface of the suction pad 22 of the table 20.

[0042] The vacuum suction by the lifter 32 continues while the substrate W is placed on the table 20 and undergoing exposure processing, and also while the vacuum suction by the table 20 is released and the substrate W is being lifted by the lifters 32, 34. An exhaust device for the suction holes 32K1, 32K2 is provided separately and is controlled by the control unit 50.

[0043] Lifter 32 is provided with outlets 32P1 and 32P2 below holding surface 32S for blowing out gas. Also, outlets 32P3 and 32P4 are provided on both sides of lifter 32. When substrate W is peeled off and lifted, gas from the gas supply source is blown out from outlets 32P1 to 32P4. Lifter 34 has a similar configuration.

[0044] FIG. 4 is a diagram showing a schematic view of the substrate W being peeled off.

[0045] When the vacuum suction is released, gas is blown out from the suction holes 20P of the table 20. At the same time, the lifters 32, 34 rise. At this time, gas is sent out from the lifters 32, 34 toward the center of the table 20. The gas blown out from the table 20 and the lifters 32, 34 causes the substrate W to be completely detached from the table 20.

[0046] If the substrate W is a thin semiconductor wafer, the substrate W itself is prone to deformation due to reduced bending rigidity. For example, even if the substrate W is a TAIKO wafer with a thick periphery, it is prone to bending near the center. This creates a situation where the substrate W is difficult to peel near the center even with the blow from the table 20. In particular, the larger the diameter of the substrate W, the greater the bending and the more difficult peeling becomes.

[0047] In this embodiment, by blowing gas into the gap between the back surface of the substrate W and the table 20 from the peripheral side (outside) of the substrate W, the substrate W can be reliably separated from the table 20 even near the center of the substrate W. In particular, by blowing gas from the table 20 and the lifters 32, 34 simultaneously, a turbulent air current is generated on the back surface of the substrate W. When the gas hits the chuck groove R1 of the suction pad 22, an upward air current is easily generated, and a force to lift the substrate W is easily generated.

[0048] Therefore, the substrate W can be reliably peeled off from the table 20 in accordance with the lifting operation of the substrate W. Furthermore, since a gas outlet is provided below the holding surface of the substrate W of the lifters 32, 34, the gas can be blown out in accordance with the lifting operation of the lifters 32, 34, thereby sending the gas directly into the gap between the back surface of the substrate W and the table 20. Note that the air may be blown out from the lifters 32, 34 after the gas is blown out from the table 20.

[0049] By arranging a pair of lifters 32, 34, the gas is sent from different directions to the back side of the substrate W. This prevents the gas from flowing outward in one direction, and ensures that the gas is directed to the unpeeled portion of the substrate W.

[0050] Each of the lifters 32 and 34 is provided with a plurality of outlets, and is configured to perform side blowing from various locations on the lifters 32 and 34. By blowing gas over a wide range toward the rear surface of the substrate W, the gas can be reliably sent to the unpeeled portion of the substrate W.

[0051] The suction holes 20P formed in the table 20 are formed asymmetrically with respect to the center C of the table 20. As a result, the gas blown out from the lifters 32, 34 collides with the gas blown out from the suction holes 20P formed at irregular positions on the table 20, which tends to create a turbulent flow.

[0052] Furthermore, the through grooves R2 formed along the radial direction of the suction pad 22 partially intersect with the concentrically formed chuck grooves R1, which prevents the side blow from the lifters 32, 34 from passing over the substrate W through the through grooves R2 and causes an upward air current by colliding with the concentric chuck grooves R1.

[0053] The lifters 32, 34 are configured to hold the peripheral edge of the substrate W. This is effective when thin semiconductor wafers with thick peripheral edges, such as TAIKO wafers, are peeled off and released from the table surface.

[0054] In this embodiment, the pair of lifters 32, 34 are arranged symmetrically with respect to the center C of the table 20, but two pairs of lifters may also be arranged symmetrically. Also, multiple lifters may be arranged asymmetrically, or a single lifter may be arranged. Furthermore, the configuration is not limited to the lifters 32, 34 being integrally provided with outlets for discharging gas, and a gas supply unit separate from the lifters may be provided so that gas is discharged from the peripheral edge side of the substrate W. The outlet of the gas supply unit is not limited to being provided below the substrate W, but may be provided outside the peripheral edge of the substrate W.

[0055] 5 is a diagram showing a modified example of the substrate holding device of this embodiment. Here, the peripheral edge of the substrate W is lifted by lift pins 132, 134. The lift pins 132, 134 are provided with outlets 132P, 134P, which send compressed air from the peripheral edge of the substrate W toward the center.

[0056] The substrate holding device 10 described above is applied to the exposure device 100, which is a projection exposure device, but it can also be applied to other exposure devices such as contact exposure devices and maskless exposure devices that can expose semiconductor wafers, printed wiring boards, LCD glass substrates, etc. Furthermore, it can be incorporated into other processing devices (semiconductor processing devices) related to semiconductor manufacturing processes, as well as exposure devices, or configured to operate in cooperation with them. For example, it can also be applied to polishing devices, etching devices, film deposition devices, etc. [Explanation of symbols]

[0057] 10 Substrate holding device 20 tables 22 Suction pad 30 Lifting mechanism 32 Lifter 34 Lifter 42 Exhaust system 44 Exhaust system 50 control section 100 Exposure device W substrate

Claims

1. a table having a holding surface capable of adsorbing a substrate; a lifting mechanism capable of holding an outer edge portion of the substrate and lifting the substrate from the table; a gas supply unit that can supply gas from the peripheral edge side of the substrate between the back surface of the substrate placed on the table or lifted by the lifting mechanism and the table; A substrate holding device comprising:

2. 2. The substrate holding device according to claim 1, wherein the gas supply unit is capable of supplying gas from a plurality of directions.

3. the lifting mechanism includes at least one lifter that can be raised from the support surface of the table; 2. The substrate holding device according to claim 1, wherein the gas supply unit supplies the gas from an outlet provided in the lifter.

4. 4. The substrate holding device according to claim 3, wherein each of the plurality of lifters is provided with a plurality of outlets.

5. 4. The substrate holding device according to claim 3, wherein a plurality of lifters are arranged symmetrically with respect to the center of the table.

6. the lifter has a holding surface capable of adsorbing a peripheral edge portion of the substrate; 4. The substrate holding device according to claim 3, wherein the gas supply unit supplies the gas from the outlet provided below the holding surface.

7. the table has a suction hole selectively communicating between a vacuum source and a gas supply source; 4. The substrate holding device according to claim 3, wherein the gas supply unit supplies the gas from the gas supply source through the outlet.

8. the table has a suction hole selectively communicating between a vacuum source and a gas supply source; 2. The substrate holding device according to claim 1, wherein the suction holes are formed at positions asymmetrical with respect to the center of the table.

9. the table has a disk-shaped suction pad formed with concentric chuck grooves and at least one through groove extending in a radial direction, 2. The substrate holding device according to claim 1, wherein the through groove intersects with a part of the chuck groove between the periphery and the center of the suction pad.

10. An exposure apparatus comprising or operating in cooperation with a substrate holding device according to any one of claims 1 to 9.

11. A semiconductor processing apparatus comprising or operating in cooperation with a substrate holding device according to any one of claims 1 to 9.

12. supplying gas from the table to the substrate sucked and attached to the table by vacuum suction when the vacuum suction is released; A method for peeling a substrate, comprising holding an outer edge portion of the substrate and lifting the substrate from the table, A substrate peeling method comprising: supplying a gas between the rear surface of the substrate and the table from the peripheral edge side of the substrate.

13. 13. The method for separating a substrate according to claim 12, wherein the gas is supplied from the table while the gas is supplied from the peripheral edge side of the substrate.

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