WO2008068943A1

WO2008068943A1 - Submerged wafer separating method, and submerged wafer separating apparatus

Info

Publication number: WO2008068943A1
Application number: PCT/JP2007/068128
Authority: WO
Inventors: Masato Tsuchiya; Ikuo Mashimo; Koichi Saito
Original assignee: Mimasu Semiconductor Industry Co., Ltd.
Priority date: 2006-12-06
Filing date: 2007-09-19
Publication date: 2008-06-12
Also published as: JP2010045057A

Abstract

This invention provides a wafer separating method and a wafer separating apparatus, which can separate a very thin wafer in a safe, simple, reliable and rapid manner. The wafer separating method comprises separating the uppermost layer wafer from a wafer laminate comprising a number of or a plurality of wafers stacked on top of each other and immersed in a liquid. The wafer separating method comprises the step of immersing a wafer laminate comprising a number of or a plurality of wafers stacked on top of each other in a liquid to provide a submerged wafer laminate, the step of holding the uppermost layer wafer in an axial direction which is deviated by an angle of 15° to 75° clockwise or anticlockwise from a crystal habit line axis of the uppermost layer wafer in the wafer laminate, the step of warping the peripheral part of the uppermost layer wafer upward so as to cause bending stress of the uppermost layer wafer in the axial direction, the step of blowing a liquid into between the lower surface of the uppermost layer wafer and the upper surface of a wafer located on and adjacent to the lower side of the uppermost layer wafer in its lower surface, and the step of lifting the uppermost layer wafer.

Description

Specification

Submerged wafer isolation method and submerged wafer isolation apparatus

Technical field

[0001] The present invention relates to a wafer on the uppermost layer of a wafer laminate in which a plurality of wafers or a plurality of wafers, particularly thin wafers, for example, a semiconductor wafer such as a silicon wafer, particularly a semiconductor wafer for solar cells is laminated. The present invention relates to a novel submerged wafer isolation method and submerged wafer isolation apparatus that can be safely and easily separated from an adjacent lower wafer.

Background art

Conventionally, semiconductor wafers (hereinafter simply referred to as wafers) such as thin silicon wafers that have been sliced and cut out with a force such as a silicon ingot, etc. are then subjected to various treatments to become final products. When performing various types of processing on this wafer, multiple or multiple wafers are stacked to form a wafer stack (commonly called a coin stack), and each wafer is separated from the wafer stack to process each wafer. It is usually done.

However, for example, oil and other liquids adhere to the surface of the wafer after various treatments, such as an abrasive (slurry) containing oil remaining on the surface of a wafer sliced from an ingot. Often doing. When multiple wafers or multiple wafers are stacked, the surface tension of these liquids existing on the wafer surface can move the wafers to the side, but from above the adjacent lower wafers. It is difficult to pull apart.

[0004] In view of this, the present inventor warps the peripheral edge of the uppermost wafer of the wafer laminated body in which a large number or a plurality of wafers are laminated, to the lower side adjacent to the lower surface of the uppermost wafer. A first wafer isolating apparatus has been proposed in which fluid is blown between the upper surface of the wafer and the uppermost wafer is raised to isolate the wafer (Patent Document 1).

[0005] The operation principle of the conventional wafer isolating apparatus will be described. The center of the uppermost wafer of the wafer stack in which a large number or a plurality of wafers are stacked is pressed by the wafer pressing means, and the wafer is attracted. The periphery of the wafer is vacuum-adsorbed by the means to warp the peripheral edge of the wafer upward, and fluid (water and water) is introduced into the gap between the lower surface of the uppermost wafer and the upper surface of the adjacent lower wafer. (Or air) and the top layer The wafer is raised and the wafer is isolated from the wafer stack.

[0006] Even with the above-described conventional wafer isolating apparatus, the force that can easily and reliably separate the wafers one by one from the wafer stack The bending stress is generated in the central part of the wafer. There were occasional accidents.

[0007] In view of this, the present inventors vacuum-sucked two or more suction positions (for example, four points) facing each other through the central portion of the wafer at the periphery of the upper surface of the wafer to By bending upward, the bending stress generated on the wafer is dispersed, and the force for isolating the wafer safely, simply and reliably can be increased, and the processing speed for isolating the wafer can be improved. The second wafer isolation system was proposed further (Patent Document 2), but there were still cases where a wafer cracking accident occurred, and the following studies were made to make further improvements. The following knowledge was obtained.

[0008] A wafer is formed by forming a single crystal rod (ingot) of silicon or the like crystal-grown by the CZ (Czochralski) method or the FZ (Floating Zone) method into a cylindrical shape by a cylindrical grinder, and then using a wire saw or the like. It is obtained by thinly slicing in a direction substantially perpendicular to the axis.

[0009] In the crystal growth of this silicon single crystal, when it is grown in the crystal orientation <100> direction by, for example, the CZ method, it appears on the outer surface of the crystal habit line kaingot formed by the crystal planes {100}. Since the crossing angle between crystal planes {100} in a silicon single crystal is 90 °, a total of four crystal habit lines are about several millimeters in height in the longitudinal direction of the outer surface of the ingot every 90 ° when viewed from the rod axis of the ingot. It will be formed as a raised protrusion (linear protrusion).

[0010] A wafer cut from an ingot grown in such a crystal orientation in the <100> direction is a disk-shaped wafer in which axes where crystal habit lines are formed (hereinafter referred to as crystal habit axes) are centered. It is orthogonal at the part, and OF (orientation flat) is provided on the outer circumference corresponding to the habit axis. In addition, in the case of a wafer for manufacturing a solar cell whose production volume has been increasing in recent years, the wafer itself is processed into a substantially rectangular shape, and each crystal habit line axis is cut out so as to be on the diagonal spring of the wafer. Re! /

[0011] These wafers have a property that they are easily cleaved in a direction parallel to the crystallographic axis.

Therefore, when isolating the wafer from the wafer stack, the peripheral edge of the wafer is warped upward. In this case, if the portion where the bending stress is generated and the crystallographic axis are aligned, it will cleave very easily. For example, in order to distribute the bending stress generated in the wafer as described above, Even if two or more pairs of suction positions (for example, four points) facing each other through the center part of the wafer at the periphery of the upper surface are attracted and the peripheral edge of the wafer is warped upward, a wafer cracking accident occurs. It will end up.

[0012] When the slurry remains on the surface of the wafer just after being cut out from the ingot, it is between the lower surface of the uppermost wafer and the upper surface of the adjacent lower wafer. Force that is suitable to use water as the fluid to be blown In the isolation, the surface tension of the water works and is pulled in the direction opposite to the direction of isolation, and the force is also simply upward. When the separation is attempted, the portion where the bending stress is generated and the portion where the surface tension of water works are matched, so that a wafer cracking accident is more likely to occur.

[0013] Once a wafer cracking accident occurs, the yield of the product is reduced, and the broken wafer fragments are scattered on the wafer isolator, so that the operation is temporarily suspended. The broken wafer fragments that have to be collected must be collected manually, causing a significant reduction in productivity.

[0014] Therefore, the present inventor can isolate a wafer in a safer, simpler and more reliable manner, and can further improve the processing speed for isolating the wafer. And a wafer isolation method and a wafer isolation machine using the wafer isolation apparatus (Patent Document 3). This wafer isolation apparatus has gained popularity recently. There is a growing need for a wafer isolation system that can safely, easily, reliably and quickly isolate very thin wafers. In recent years, since ultra-thin wafers with a thickness of about 200 m have been used, wafers are becoming more susceptible to cracking, and the problem of wafer cracking has become more prominent! .

Patent Document 1: JP-A-9 64152

Patent Document 2: WO2004 / 051735

Patent Document 3: WO2004 / 102654

Disclosure of the invention

Problems to be solved by the invention [0015] The present invention has been made in view of the above problems, and provides a wafer isolation method and a wafer isolation apparatus capable of isolating an extremely thin wafer safely, simply, reliably and quickly. Let's call it Mejiro.

Means for solving the problem

[0016] In order to solve the above-mentioned problem, the method for isolating wafers in liquid according to the present invention is to remove the uppermost wafer from a wafer laminate in which a large number or a plurality of wafers are immersed in a liquid. A wafer isolation method for isolation, comprising: immersing a wafer laminate in which a large number of wafers or a plurality of wafers are laminated in a liquid; and preparing a crystal of a wafer in the uppermost layer of the wafer laminate A step of pressing the uppermost wafer in an axial direction shifted by 15 ° to 75 ° clockwise or counterclockwise from the winding axis; and the bending stress of the uppermost wafer is generated in the axial direction. A step of bending the peripheral edge of the upper wafer upward, a step of blowing liquid between the lower surface of the uppermost wafer and the upper surface of the lower wafer adjacent to the lower surface, and raising the uppermost wafer Step and Look, is characterized in that so as to isolate the wafer.

[0017] The angle in the axial direction shifted clockwise or counterclockwise from the crystal habit axis is preferably 30 ° to 60 °, more preferably 40 ° to 50. And most ideally 45 °. In the case of a wafer with a crystal orientation of 100>, the crystal habit axis is perpendicular to the center of the wafer, so the wafer is warped with the axis direction shifted by 45 ° clockwise or counterclockwise from the crystal habit axis as the support axis. This is because it is most difficult to cleave.

[0018] When the uppermost wafer is isolated by being raised, it is preferable that the uppermost wafer is raised while being inclined in the horizontal direction. In the submerged wafer isolation method of the present invention, since the entire wafer stack is immersed in the liquid, the uppermost wafer is raised while being inclined in the horizontal direction during isolation. Therefore, the partial force acting by the decompression force generated between the lower surface of the uppermost wafer and the upper surface of the lower wafer adjacent to the lower surface is shifted from the portion where the bending stress of the uppermost wafer is generated. A wafer cracking accident will not occur due to the difference. In addition, the liquid on the uppermost wafer also stays on the wafer and can reduce wafer cracking.

[0019] In order to reduce wafer cracking accidents, the uppermost wafer is tilted in the horizontal direction. As the inclination angle when raising it, 2 ° to 60 ° is preferable, and 2 ° to 40 ° is preferable, and 5 ° to 20 °. Is most preferred.

[0020] The submerged wafer isolation device of the present invention also isolates the uppermost wafer from a wafer stack in which a large number or a plurality of wafers immersed in a liquid are stacked. A support plate provided so as to be movable up and down, wafer shaft pressing means provided on the lower surface of the support plate, and a wafer on the uppermost layer provided on a peripheral portion of the lower surface of the support plate. Wafer adsorbing means for adsorbing one or more opposing adsorbing positions on the periphery of the upper surface of the substrate, liquid ejecting means provided on the outer side corresponding to the wafer adsorbing means, and the entire wafer stack are immersed An immersion container configured to fill the immersion liquid and perform the wafer isolation operation in the liquid, and from the crystal axis of the uppermost wafer by the wafer axis pressing means. The top layer of the uppermost layer is shifted in the axial direction by 15 ° to 75 ° clockwise or counterclockwise. The wafer adsorbing means opposes the upper surface of the uppermost wafer through the center of the upper surface of the wafer so that the wafer is pressed and bending stress of the uppermost wafer is generated in the axial direction. While adsorbing one or more pairs of adsorbing positions and curving the peripheral edge of the uppermost layer wafer upward at one or more pairs of adsorbing positions, the lower wafer adjacent to the lower surface and the lower wafer adjacent to the lower surface A liquid is blown by the liquid ejecting means between the upper surface of the wafer and the uppermost wafer is raised to isolate the wafer.

[0021] The angle in the axial direction shifted clockwise or counterclockwise from the crystal habit axis is preferably 30 ° to 60 °, more preferably 40 ° to 50 °, and most preferably 45 °. This is as described above.

[0022] The wafer shaft pressing means includes a plurality of wafer pressing members arranged in one direction on the lower surface of the support plate, or a wafer elongated in one direction provided on the lower surface of the support plate. It is preferably made of a pressing member. In other words, the wafer presser means in the conventional wafer isolating apparatus functions as a fulcrum when the wafer is warped and serves as a fulcrum for supporting one point at the center of the wafer. This is because it functions as a support shaft when the wafer is warped and serves as a support shaft for supporting the predetermined axial direction of the wafer, so that it is necessary to support the wafer in an axial direction that is not a point.

[0023] Two or more pairs of the wafer adsorbing means are provided, and the wafer is provided at the periphery of the upper surface of the uppermost wafer. It is preferable to adsorb two or more pairs of adsorbing positions opposite to each other via the central portion of the wafer and to warp the peripheral portion of the uppermost wafer at the two or more adsorbing positions upward.

[0024] It is preferable that the support plate is formed in a cross shape, an X shape, or a horizontal H shape, and the wafer suction means is provided around the lower surface of the support plate.

[0025] It is preferable that the support plate is provided so as to be inclined in the horizontal direction when moved upward. When isolating as described above, the effect of the surface tension of the liquid can be reduced by raising the uppermost wafer while tilting in the horizontal direction. For this purpose, by providing the support plate to be inclined in the horizontal direction when moving upward, the wafer suction means and wafer shaft holding means provided on the support plate are similarly inclined in the horizontal direction. When the uppermost wafer is attracted and lifted by the wafer attracting means, it can be tilted in the horizontal direction. As the immersion liquid and the jet liquid, water may be used! /, But a chemical solution such as a surface active agent added to water may also be used.

[0026] In order to reduce wafer cracking accidents, the tilt angle when the uppermost wafer is tilted and raised in the horizontal direction is preferably 2 ° to 60 °, and more preferably 2 ° to 40 °. As described above, 5 ° to 20 ° is most preferable.

[0027] Preferably, the wafer suction means is a vacuum suction nozzle having a liquid ejecting function, and a liquid is ejected from the vacuum suction nozzle to clean the suction position of the uppermost wafer of the wafer stack. Thin layer silicon wafers, etc., sliced from silicon ingots, etc. have liquids such as slurry at the time of slicing remaining, and the remaining liquids such as slurry are semi-dried on the wafer surface over time. As a result, the suction by the wafer suction means fails or the suction becomes incomplete and becomes very unstable. Therefore, as described above, if the liquid is ejected from the vacuum suction nozzle to clean the suction position, problems such as suction failure and incomplete suction can be solved.

[0028] It is preferable that the wafer suction means is a vacuum suction nozzle having a liquid jet function, and a liquid is jetted from the vacuum suction nozzle to clean a pipe communicating with the vacuum suction nozzle. Since the liquid such as slurry at the time of slicing remains on the wafer as described above, when the liquid is adsorbed, the liquid such as slurry is sucked into the pipe communicating with the vacuum suction nozzle. Dirty or clogged, causing malfunction. So vacuum If the pipe is cleaned by spraying the liquid from the suction nozzle, it is possible to prevent such a malfunction.

[0029] The wafer suction means is a vacuum suction nozzle having a liquid jet function, and it is preferable that the wafer suction means jets liquid from the vacuum suction nozzle so that the wafer suction means temporarily hoveres on the wafer surface. . Since semiconductor wafers such as silicon wafers are brittle materials, they can be easily damaged by impacts or the like. In particular, when the wafer suction means is lowered and brought into contact with the wafer surface and vacuum suction is performed, if the wafer suction means is simply dropped by its own weight, the wafer suction means rapidly drops and collides with the wafer surface. Damage to the wafer will occur. Therefore, if the wafer suction means is lowered while spraying liquid from the vacuum suction nozzle, and the wafer suction means is temporarily hovered on the wafer surface, such damage to the wafer can be prevented. it can.

[0030] The wafer stack further includes a wafer stack holding means for holding the wafer stack so as to be movable up and down, and a wafer position confirmation sensor for checking the height position of the uppermost wafer. The wafer laminate may be configured to be set at a predetermined height position by detecting whether the laminate has reached a predetermined height by the wafer laminate holding means or not by the wafer position confirmation sensor. I'll do it.

The invention's effect

[0031] According to the present invention as described above, it is possible to provide a submerged wafer isolation method and a submerged wafer isolation apparatus capable of isolating an ultrathin wafer safely, simply, reliably and quickly. If you can!

Brief Description of Drawings

[0032] [FIG. 1] A plan view showing an adsorption position when a wafer is isolated by the wafer isolation method of the present invention, (a) is a disk-shaped wafer, (b) is a substantially square shape. In the case of a shaped wafer

FIG. 2 is an explanatory side view showing the principle of operation for tilting a wafer in the horizontal direction during wafer isolation in the wafer isolation method of the present invention. FIG. 2 (a) shows a state in which the wafer is attracted and warped. (B) shows the wafer tilted in the horizontal direction.

FIG. 3 is a partial cross-sectional side view showing the case where the support plate of the wafer isolation apparatus of the present invention is in the lowered position It is surface explanatory drawing.

FIG. 4 is a partial cross-sectional side view illustrating a case where the support plate of the wafer isolation device of the present invention is in the upper limit position.

FIG. 5 is a plan view of the wafer isolating apparatus of the present invention.

FIG. 6 is a flowchart showing an operation flow of the wafer isolation apparatus of the present invention.

FIG. 7 is a main part explanatory diagram showing an inclination angle when the uppermost wafer is raised while being inclined in the horizontal direction.

Explanation of symbols

[0033] 2: Wafer isolation apparatus, 2A: Wafer isolation apparatus main body, 3: Side substrate, 4: Wafer stack holding means, 5: Holding member, 6: Holding rod, 7: Driving means, 8: Container 9a, 9b: Wafer position detection sensor, 10: Movable member, 11: Air cylinder means, 12: Support plate, 13: Support base plate, 15a, 15b: Bonoret, 19: Laser, 20: Ueno carriage presser Means, 20a, 20b: Ueno, presser foot, 22a, 22b, 22c, 22d: Ueno soot adsorption means, 23: Self-tube, 24, 24a, 24b, 24c, 24d: i night-body injection means, 25 : Piping, 26: Liquid injection hole, 28: Mounting bracket, 30: Connecting member, 32: Plate body, 36: Through hole, 38: Guide rod, D: Gap, F: Injection liquid, L: Crystalline wire, W: Wafer, W1: Upper layer Ueno, W2: Lower Ueno, Wa, Wb: Ueno, WS: Wafer stack, 130: Wafer mounting, 132: Immersion liquid, 132a: Liquid surface, 134: Immersion Container, 136: liquid supply port, 138: drainage port, 140: side wall, 142: Overflow liquid.

BEST MODE FOR CARRYING OUT THE INVENTION

[0034] Embodiments of the present invention will be described below, but the following description is given by way of example and should not be construed in a limited way! /!

FIG. 1 is a plan view showing a suction position when a wafer is isolated by the wafer isolation method of the present invention, (a) is a disk-shaped wafer, and (b) is a substantially square shape. This is the case of a shaped wafer.

In FIG. 1 (a), the symbol Wa is a disk-shaped wafer, which is a wafer with a crystal orientation of 100>. The axis of the line segment indicated by reference signs A—A ′ and the axis of the line segment indicated by reference signs BB ′ are crystal habit axes, and are orthogonal at the center of the wafer. OF (orientation flat) is provided on the outer circumference corresponding to the crystallographic axis! [0037] Then, the axial direction shifted by 45 ° from the crystal habit axis (the axial direction of the line segment indicated by the symbol L-L ') is pressed by wafer pressing members 20a and 20b as wafer axis pressing means 20, Two pairs of suction positions facing each other through the center of the wafer Wa are vacuum-sucked by a pair of wafer suction means 22a and 22b and a pair of wafer suction means 22c and 22d. .

[0038] Then, a set of wafer suction means 22a, 22b and a wafer suction hand with the axial direction pressed by the wafer pressing members 20a, 20b (the axial direction of the line indicated by the symbol L L ') as a support shaft Wafer Wa was bent by the pair of steps 22c and 22d, and the crystal habit line axial force, shifted by 45 °, only in the portion along the axis direction that was difficult to cleave (the axial direction of the line segment indicated by the symbol L L ′) Bending stress is generated. As a result, there is no bending stress on the crystallographic axis that is easy to cleave (the axis of the line indicated by the symbol A-A 'or the axis of the line indicated by the symbol B-B'). Therefore, wafers can be isolated safely and reliably.

In FIG. 1 (b), symbol Wb is a wafer for manufacturing a substantially rectangular solar cell. In the case of wafer Wb, the crystallographic axis (the axis of the line indicated by reference A—A ′ or the axis of the line indicated by reference B—B ′) is on the diagonal of the wafer.

[0040] In the case of wafer Wb as well, as in FIG. 1 (a), the axial direction shifted by 45 ° from the crystal habit axis (the axial direction of the line segment indicated by the symbol L L ') is used as the wafer axis pressing means. The wafer holding members 20a and 20b are used to hold two pairs of suction positions on the periphery of the upper surface of the wafer Wb opposite to each other via the center of the wafer. 2 Vacuum adsorption with 2c, 22d pair.

[0041] As a result, a bending stress is generated only in a portion along the axis direction that is difficult to cleave (an axis direction indicated by a symbol L L ') deviated by 45 ° from the crystallographic axis. Use the power S to isolate.

[0042] FIG. 2 is a side view for explaining the principle of operation in which the wafer is tilted in the horizontal direction during wafer isolation in the wafer isolation method of the present invention, and (a) shows the wafer attracted and warped. (B) shows the wafer tilted in the horizontal direction during isolation.

In FIGS. 2 (a) and 2 (b), symbol WS is a wafer laminate in which a large number or a plurality of wafers W are laminated. The wafer laminate WS is placed on the upper surface of the wafer platform 130. Reference numeral 10 is a movable member that can move up and down above the wafer stack WS. It is a cylinder rod of an air cylinder. The movable member 10, that is, the cylinder rod is configured to descend by its own weight when the air cylinder air is turned off, and to rise when the air cylinder air is turned on.

A support base plate 13 is attached to the lower end portion of the movable member 10. A support plate 12 is attached to the support base plate 13 with bolts 15a and 15b in a state where there is play, so that the play widths of the bolts 15a and 15b are different. For example, bolts 15a and 15b as shown in the figure use bolts of different lengths, and are installed so that the free width of the bolt 15a is larger than the direction force S bolt 15b.

A wafer shaft pressing means 20 is provided on the lower surface of the support plate 12. As described above, the wafer shaft pressing means 20 is composed of the wafer pressing members 20a and 20b (see FIG. 1), and presses a predetermined axial direction of the wafer W1. Wafer adsorbing means 22a, 22b, 22c, 22d are provided on the periphery of the lower surface of the support plate, and liquid ejecting means 24a, 24b, 24c, 24d are respectively provided on the outer sides corresponding thereto! /, (See Fig. 5).

[0046] The greatest feature of the present invention is that an immersion container 134 is provided which is configured to fill the immersion liquid 132 so that the entire wafer laminate WS is immersed and to perform the wafer isolation operation in the liquid. That is. The immersion container 134 has a liquid supply port 136 and a liquid discharge port 138. The side wall 140 on the side of the drainage port 138 of the immersion vessel 134 is such that the entire wafer stack WS can be immersed, that is, the liquid level 132a of the immersion liquid is higher than the upper surface of the uppermost wafer W1 of the wafer stack WS. The height is set so as to be located above, and excess immersion liquid is discharged from the drain port 138 as the overflow liquid 142. Water may be used as the immersion liquid, but a chemical solution such as a surfactant added to water can also be used.

[0047] First, the wafer W1 in the uppermost layer of the wafer laminate WS is axially shifted by 45 ° from the habit line axis of wafer W1 by the wafer axis pressing means 20 (the line indicated by the symbol L L ′ in FIG. 1). Press the minute axis direction). Next, with the wafer shaft pressing means 20 as a supporting shaft, the peripheral part of the wafer W1 is adsorbed by adsorbing the peripheral part of the wafer W1 by the set of the wafer adsorbing means 22a, 22b and the set of the wafer adsorbing means 22c, 22d, A gap D between the lower surface of the uppermost wafer Wl and the upper surface of the lower wafer W2 adjacent to the lower surface by the liquid ejecting means 24a, 24b, 24c, 24d. Blow liquid F (eg, water) into the tank [Fig. 2 (a)].

[0048] When the movable member 10 is raised, the support plate 12 is inclined in the horizontal direction toward the bolt 15a having a large play width, so that the wafer W1 is also inclined in the horizontal direction [FIG. 2 (b)]. . In the present invention, the entire wafer laminate WS is immersed in the immersion liquid. Therefore, the liquid decompression force when the uppermost wafer W1 is isolated from the adjacent lower wafer W2 is a bending stress. It works at the part shifted to the bolt 15a side from the part where it occurs, and the part where the liquid pressure is reduced and the part where the bending stress of the uppermost wafer is not aligned do not match. This makes it difficult for a wafer cracking accident to occur. Furthermore, since the liquid on the wafer also stays on the wafer, wafer cracking can be reduced.

Next, the configuration of the wafer isolation apparatus of the present invention will be described with reference to FIGS.

FIG. 3 is a partial cross-sectional side view showing the case where the support plate of the wafer isolation apparatus of the present invention is in the lowered position, and FIG. 4 shows the support plate of the wafer isolation apparatus of the present invention in the upper limit position. FIG. 5 is a plan view of a wafer isolating apparatus according to the present invention.

In the figure, reference numeral 2 denotes a wafer isolation apparatus according to the present invention, and 2A denotes a wafer isolation apparatus main body. Reference numeral 4 denotes a wafer laminate holding means for holding a wafer laminate WS in which a large number or a plurality of semiconductor wafers such as silicon wafers are laminated. The wafer laminate holding means 4 includes a plurality of holding rods 6 for positioning and holding the wafer laminate WS. A holding member 5 is attached to the wafer laminate holding means 4, and the holding member 5 is moved up and down by a driving means 7 (for example, a motor), and the wafer laminate holding means 4 attached to the holding member 5. Can move up and down.

[0051] The greatest feature of the wafer isolation device 2 of the present invention is that the wafer stack WS is filled with the immersion liquid 132 so that the entire wafer laminate WS is immersed, and the wafer isolation operation is performed in the liquid. The container 134 was installed. The immersion container 134 has a liquid supply port 136 and a liquid discharge port 138. The side wall 140 on the side of the drainage port 138 of the immersion container 134 is such that the entire surface of the wafer stack WS can be immersed, that is, the liquid level 132a of the immersion liquid is higher than the upper surface of the uppermost wafer W1 of the wafer stack WS. The height is set so as to be positioned above, and the excess liquid is discharged from the drain port 138 as the overflow liquid 142. [0052] On the side wall 140, wafer position confirmation sensors 9a and 9b for confirming the height position of the uppermost wafer of the wafer stack WS are provided. In the example, the height position of the uppermost wafer of the wafer laminate WS is detected by a laser 19), and the wafer laminate WS is set at a predetermined height position. In the example shown in the figure, the force used to confirm the wafer position with a laser sensor is sufficient as long as the height position of the uppermost wafer of the wafer stack WS can be confirmed. Therefore, the wafer position confirmation sensor is an ultrasonic sensor. Or other sensor means.

The movable member 10 is provided so as to be movable up and down above the wafer laminate holding means 4 and serves as a cylinder rod for the air cylinder means 11. The movable member 10 as a cylinder rod descends by its own weight when the air of the air cylinder means 11 is turned off, and rises when the air of the air cylinder means 11 is turned on.

A support base plate 13 is attached to the lower end portion of the movable member 10. The support base plate 13 is suspended by a plurality of suspension members having different play widths in the vertical direction so that the support plate 12 is inclined in the horizontal direction when the support plate 12 is suspended. As the hanging member, for example, a bolt and nut can be used. In this case, the bolts 15a and 15b as shown in the figure use bolts having different lengths so that the play widths in the vertical direction are different. The bolt 15a side has a larger play width than the bolt 15b side so that the support plate is inclined to the bolt 15a side when suspended from the support base plate 13. 12 is suspended. Needless to say, the configuration in which the play width in the vertical direction of the suspending member is different can take various configurations such as different play widths using springs having different elasticity.

Yes

[0055] The support plate 12 is not particularly limited as long as it is a member longer than the diameter of the wafer in at least one direction. Although it may be a circle or a rectangle larger than the wafer, it is preferably formed in a cross shape, an X shape, or a horizontal H shape. In the illustrated example, the support plate 12 is formed in a cross shape (see FIG. 5).

Reference numeral 20 denotes a wafer shaft pressing means made of an elastic material, such as a rubber material, suspended from the lower surface of the support plate 12. As described above, the wafer axis pressing means 20 is angled from 15 ° to 75 °, preferably 30 ° to clockwise or counterclockwise from the crystal habit line axis of wafer. 60 °, more preferably 40 ° to 50 °, most preferably 45 ° when the uppermost wafer is pressed in the axial direction, and the wafer suction means 22a to 22d suck the peripheral edge of the wafer and deflect it upward. It is a support shaft. In the illustrated example, a predetermined axial direction of the wafer is pressed by the wafer pressing members 20a and 20b arranged in a predetermined direction as the wafer axis pressing means 20 (see FIG. 5).

[0057] Wafer adsorbing means 22a, 22b, 22c, and 22d for vacuum adsorbing predetermined adsorbing positions (four locations in the illustrated example) around the upper surface of the wafer are provided around the lower surface of the support plate 12 (see FIG. 5). )

Yes

[0058] The base end portions of the wafer adsorbing means 22a to 22d are connected to a vacuum source (not shown) by pipes 23 so as to be turned on and off, and when the tip vacuum adsorbing portion adsorbs the wafer, the vacuum source The vacuum connection is turned on and the vacuum connection is turned off! /, And the connection with the vacuum source is turned off.

A vacuum suction nozzle (not shown) for performing vacuum suction is provided at the vacuum suction portion at the tip of the wafer suction means 22a to 22d. The vacuum suction nozzle can also be provided with a liquid jetting function for jetting a liquid such as water. In this case, the pipe 23 can be turned on / off with a water supply source (not shown) and switched to a vacuum source. Connecting. When injecting liquid from a vacuum adsorption nozzle, switch from the vacuum source to the water supply source, turn on the connection with the water supply source and inject the liquid, do not inject the liquid! The connection to is also turned off.

[0060] The liquid ejection function of the vacuum suction nozzle is that vacuum suction is performed by the vacuum suction nozzle. Since slurry or the like remains on the wafer, if vacuum suction is repeated, the vacuum suction nozzle The piping 23 communicating with the vacuum suction nozzle is contaminated to cause a malfunction. Therefore, the piping 23 communicating with the vacuum suction nozzle is cleaned by ejecting a liquid such as water from the vacuum suction nozzle. If the wafer is contaminated with slurry or the like, vacuum suction by the vacuum suction nozzle may become unstable, so before performing vacuum suction, a liquid such as water is jetted from the vacuum suction nozzle to The wafer suction position is cleaned, and as described above, the movable member (cylinder rod) 10 is lowered by its own weight, and the wafer suction means 2 equipped with the vacuum suction nozzle is also provided. 2a-22d also descends If this drop suddenly drops, the vacuum suction nozzle and the wafer may collide and damage the wafer. Therefore, liquid is ejected from the vacuum suction nozzle, and the vacuum suction nozzle This prevents the wafer from being damaged by temporarily hovering the wafer surface.

Reference numerals 24a, 24b, 24c, and 24d are liquid ejecting means, and are arranged on the peripheral end portion of the support plate 12 so as to be located outside corresponding to the wafer suction means 22a, 22b, 22c, and 22d. It is provided via a mounting bracket 28. Liquid ejection holes 26 are formed in the lower end portions of the liquid ejecting means 24a to 24d. The liquid ejecting means 24a to 24d communicate with the pipe 25, respectively, and are connected to a liquid supply source (not shown) so as to be turned on and off.

[0062] The liquid ejecting means 24a to 24d have a gap D formed between the lower surface of the uppermost wafer W1 of the wafer stack WS and the upper surface of the lower wafer W2 adjacent to the lower surface (see FIG. 2). ) Inject liquid. As the liquid to be ejected, water may be used, but a liquid obtained by adding a chemical solution such as a surfactant to water can also be used.

Reference numeral 32 denotes a plate-like body having one end attached to the lower end of the air cylinder means 11, and the other end of the plate-like body 32 is connected to the side base 3. Reference numeral 36 is a through hole formed in the central portion of the plate-like body 32, and a guide rod 38 standing through the support base plate 13 via a connecting member 30 is passed through the through hole 36, The support base plate 13 is prevented from shaking through the guide rod 38. Note that the connection member 30, the through hole 36, and the guide rod 38 may be omitted if the support base plate 13 does not need to be steady.

Next, the operation flow of the above configuration will be described with reference to FIG. FIG. 6 is a flowchart showing an operation flow of the wafer isolating apparatus of the present invention. As described above, the wafer isolation apparatus 2 is prepared by immersing the wafer laminate WS in which a large number or a plurality of wafers are laminated in the immersion liquid 132 of the immersion container 134. First, the operation of the wafer isolating apparatus 2 is started by turning on a starting means (not shown).

The support plate 12 starts to descend by its own weight when the air of the air cylinder means 11 is turned off (step 101). At the same time, the liquid 23 such as water is ejected from the nozzles of the wafer suction means 22a to 22d, thereby cleaning the pipe 23 communicating with the nozzles (step 102). [0066] When the wafer shaft pressing means 20 and the wafer suction means 22a 22d provided on the lower surface of the support plate 12 come into contact with the uppermost wafer W1, it is lowered by its own weight! /, And the support plate 12 is automatically lowered. Is stopped (step 103). At this time, the wafer axis holding means 20 is shifted from the habit axis of the wafer clockwise or counterclockwise by an angle of 15 ° 75 °, preferably 30 ° 60 °, more preferably 40 ° 50 °, and most preferably 45 °. The uppermost wafer W1 is pressed in the axial direction.

[0067] When a sensor that detects whether or not the support plate 12 is in contact with the upper surface of the uppermost wafer W1 is installed, and the contact of the support plate 12 with the uppermost wafer W1 is detected, It can also be configured so that the lowering of the support plate 12 is terminated by a command from the sensor.

Next, the wafer adsorbing means 22a and 22d are operated to adsorb the periphery of the upper surface of the uppermost wafer W1, and warp the peripheral edge of the uppermost wafer W1 upward (step 104). At this time, since the entire wafer laminate WS is immersed in the liquid, the surface between the peripheral edge of the uppermost wafer W1 and the peripheral edge of the lower wafer W2 adjacent to the uppermost wafer W1. The tension is getting lower.

[0069] From the liquid ejecting means 24 to the gap D (see Fig. 2) formed between the peripheral edge of the uppermost wafer W1 and the peripheral edge of the lower wafer W2 adjacent to the uppermost wafer W1. Water or the like is sprayed (step 105). By this liquid jetting, the surface tension between the peripheral edge of the uppermost wafer W1 and the peripheral edge of the lower wafer W2 adjacent to the uppermost wafer W1 is further reduced.

[0070] In this manner, the surface tension between the uppermost wafer W1 and the lower wafer W2 adjacent to the uppermost wafer W1 is extremely low, and can be easily separated. Then, the support plate 12 is raised while the uppermost wafer W1 is adsorbed to the wafer adsorbing means 22a 22d (step 106). At this time, since the support plate 12 rises while tilting in the horizontal direction, the influence of the surface tension of water is further reduced. As the uppermost wafer W1 starts to rise, the liquid jet stops. As shown in FIG. 7, the inclination angle Θ when the uppermost wafer W1 is raised while being inclined in the horizontal direction is preferably 2 ° 60 ° in order to reduce wafer cracking accidents. 2 ° 40 ° is preferred 5 ° 20 ° is most preferred Yes.

The support plate 12 moves to the upper limit (step 107). Therefore, the uppermost wafer adsorbed by the wafer adsorbing means 22a to 22d is released from the vacuum adsorbing, and is transferred to the next process by an appropriate means such as a robot arm (step 108). At this point, one cycle of the operation of the wafer isolator 2 is completed. By repeating the same procedure, it is possible to isolate the wafer stacks WS one after another.

Claims

The scope of the claims

[1] Wafer stack in which a large number of wafers or a plurality of wafers immersed in a liquid are laminated, and a wafer isolation method for isolating the uppermost wafer, A step of immersing the wafer stack on which the wafer is stacked in a liquid and preparing the wafer stack, and shifting the angle from 15 ° to 75 ° clockwise or counterclockwise from the crystal axis of the uppermost wafer of the wafer stack. Pressing the uppermost wafer in the axial direction, bending the peripheral edge of the uppermost wafer upward so that bending stress of the uppermost wafer is generated in the axial direction, and A step of blowing liquid between the lower surface of the upper layer wafer and the upper surface of the lower wafer adjacent to the lower surface; and raising the uppermost wafer; and isolating the wafer In-liquid liquid Isolation method.

[2] The submerged wafer isolation method according to [1], wherein an angle in an axial direction shifted clockwise or counterclockwise from the crystal habit axis is 30 ° to 60 °.

[3] The submerged wafer isolation method according to claim 1 or 2, wherein when the uppermost wafer is raised and isolated, the uppermost wafer is raised while being inclined in the horizontal direction.

Yes

[4] A submerged wafer isolating apparatus for isolating the uppermost wafer from a wafer laminate in which a large number of wafers or a plurality of wafers immersed in a liquid are laminated. A holding plate, wafer shaft pressing means provided on the lower surface of the support plate, and one or more pairs of suction positions opposed to each other on the upper surface periphery of the uppermost wafer. Wafer adsorption means for adsorbing, liquid ejecting means provided on the outer side corresponding to the wafer adsorption means, the immersion liquid is filled so that the whole wafer stack is immersed, and the wafer separation operation is liquid An immersion vessel configured to be able to perform in the wafer, and the wafer axis pressing means is shifted from the crystal habit axis of the uppermost wafer by an angle of 15 ° to 75 ° clockwise or counterclockwise. The uppermost wafer is pressed in the axial direction and the uppermost wafer In order to generate a bending stress in the axial direction, the wafer suction means sucks one or more pairs of suction positions facing each other through the center of the wafer at the periphery of the upper surface of the uppermost wafer, The liquid jetting means between the lower surface of the uppermost wafer and the upper surface of the lower wafer adjacent to the lower surface while the peripheral edge of the uppermost wafer is warped upward at one or more pairs of suction positions. A submerged wafer isolation device characterized by isolating a wafer by blowing a liquid and raising the uppermost wafer.

[5] The angle in the axial direction shifted clockwise or counterclockwise from the crystal habit axis is 30 ° to 60 °.

5. The submerged wafer isolation device according to claim 4, wherein

6. The submerged wafer isolation device according to claim 4 or 5, wherein the wafer shaft pressing means comprises a plurality of wafer pressing members arranged in one direction on the lower surface of the support plate.

7. The submerged wafer isolation device according to claim 4 or 5, wherein the wafer shaft pressing means comprises a wafer pressing member elongated in one direction provided on the lower surface of the support plate.

[8] Two or more pairs of the wafer suction means are provided, and two or more pairs of suction positions facing each other through the central portion of the wafer on the upper surface of the uppermost wafer are sucked. The peripheral edges are bent upward at two or more pairs of suction positions.

7. The submerged wafer isolation device according to 1 above, wherein

[9] The support plate according to any one of claims 4 to 8, wherein the support plate is formed in a cross shape, an X shape, or a horizontal H shape, and the wafer suction means is provided around the lower surface of the support plate. The liquid wafer isolation device according to item 1.

10. The submerged wafer isolation device according to any one of claims 4 to 9, wherein the support plate is provided so as to be inclined in a horizontal direction when moving upward.

[11] The liquid wafer isolation device according to any one of [4] to [10], wherein the liquid is water.

[12] The wafer suction means is a vacuum suction nozzle having a liquid ejecting function, and ejects liquid from the vacuum suction nozzle to clean the suction position of the uppermost wafer of the wafer stack. The in-liquid wafer isolation device according to any one of claims 4 to 11;

[13] The wafer suction means is a vacuum suction nozzle having a liquid jet function, jets liquid from the vacuum suction nozzle, and cleans a pipe communicating with the vacuum suction nozzle. Any of 12 forces, the submerged wafer isolation device according to 1;

[14] The wafer suction means is a vacuum suction nozzle having a liquid ejecting function, and the liquid is ejected from the vacuum suction nozzle so that the wafer suction means temporarily hoveres on the wafer surface. 14. The liquid wafer isolation according to any one of claims 4 to 13; apparatus.

A wafer stack holding means for holding the wafer stack in a vertically movable manner; and a wafer position confirmation sensor for checking the height position of the uppermost wafer, wherein the wafer stack has a predetermined height. 15. The submerged wafer isolation device according to any one of claims 4 to 14, wherein the wafer isolation device is set at a vertical position.