Wafer separation device and method, and silicon wafer manufacturing method

Abstract

To provide a wafer separation device and method which inhibit poor separation of a wafer easily, and to provide a silicon wafer manufacturing method.SOLUTION: A wafer separation device 1 has: an injection port 2 from which a fluid is injected; a rolling element 3; and a supporter 4 which holds the rolling element 3 in a manner that the rolling element 3 can roll and move integrally therewith, can reciprocate, is biased to one side in a reciprocating direction, and integrally continues into the injection port 2.SELECTED DRAWING: Figure 3

Description

[Technical Field]

[0001] The present invention relates to a wafer separation apparatus and method, and a method for manufacturing silicon wafers. [Background technology]

[0002] Semiconductor wafers (for example, silicon wafers) are manufactured into products by slicing a semiconductor ingot into a plurality of wafers in a slicing process, and then polishing each wafer.

[0003] The wafers obtained by slicing a semiconductor ingot are covered with sludge derived from the grinding fluid used in the slicing process. Therefore, after the slicing process, the wafers are sent one by one to a cleaning process where they are cleaned, and then stored in cassettes in groups of several and transported to the polishing process. Here, a wafer separation device and method are known that injects a fluid into the gap between the outermost wafer and the other wafers to sequentially separate the wafers from a wafer stack formed by stacking multiple wafers and send them to the cleaning process (see, for example, Patent Documents 1 and 2). [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Laid-Open No. 2015-233059 [Patent Document 2] Japanese Patent Application Publication No. 9-237817 Summary of the Invention [Problem to be solved by the invention]

[0005] In a wafer stack, tilting of the outermost wafer may occur due to sludge getting caught between the wafers. If this tilting causes a change in the relative position between the fluid injection port and the target position to which the injected fluid should flow, the fluid may not be able to flow to the target position, which may result in poor separation of the outermost wafer. Such poor separation of the wafers may result in a stop of the cleaning process and reduce production efficiency, so it is desirable to minimize this as much as possible.

[0006] SUMMARY OF THE INVENTION It is therefore an object of the present invention to provide a wafer separation apparatus and method, and a method for manufacturing silicon wafers, that can easily prevent wafer separation defects. [Means for solving the problem]

[0007] One aspect of the present invention is as follows.

[0008] [1] an injection port for injecting a fluid; A rolling element; a holder that holds the rolling elements so that they can roll and move together, is reciprocatingly movable, is biased to one side in the reciprocating direction, and is integrally connected to the injection port.

[0009] [2] The wafer separation device according to [1], wherein the holder is capable of reciprocating motion by rotating.

[0010] [3] The wafer separation device according to [1] or [2], wherein the rolling elements are rollers.

[0011] [4] A wafer separation method using the wafer separation apparatus according to any one of [1] to [3], an ejection nozzle moving step of moving the ejection nozzle in accordance with a position of the end face of the outermost wafer by bringing the rolling element into contact with the end face in the stacking direction of the outermost wafer included in the wafer stack; a separation step of injecting a fluid from the injection port moved in the injection port moving step, thereby causing the fluid to flow between the outermost wafer and other wafers, thereby separating the outermost wafer; a transport step of moving the outermost wafer separated by the separating step in a transport direction intersecting the stacking direction.

[0012] [5] The wafer separation method according to [4], wherein in the ejection port moving step, the rolling element is brought into contact with a portion of the end face of the outermost wafer on the ejection port side.

[0013] [6] [4] or [5], using the wafer separation method described in The method for producing a silicon wafer, wherein the wafer is a silicon wafer. [Effects of the Invention]

[0014] According to the present invention, it is possible to provide a wafer separation apparatus and method, and a silicon wafer manufacturing method, which are capable of easily suppressing wafer separation defects. [Brief explanation of the drawings]

[0015] [Figure 1] 1 is a schematic diagram showing a state in which a wafer stack is being sent to one side in the stacking direction in the wafer separation apparatus of the embodiment of the present invention. FIG. [Figure 2] 3 is a schematic diagram showing the operation of the wafer separation device shown in FIG. 1 when no sludge is caught in the wafer stack. FIG. [Figure 3] 2 is a schematic diagram showing the operation of the wafer separation device shown in FIG. 1 when the outermost wafer is tilted due to sludge getting caught in the wafer stack. FIG. [Figure 4] 4 is a schematic diagram showing the operation of the wafer separation device when the outermost wafer is tilted in the opposite direction to that in FIG. 3 due to sludge being trapped. FIG. DETAILED DESCRIPTION OF THE INVENTION

[0016] Hereinafter, an embodiment of the present invention will be described with reference to the drawings.

[0017] As shown in Figures 1 and 2, in one embodiment of the present invention, a wafer separation device 1 has an injection port 2 that injects a fluid, a rolling body 3, and a holder 4 that holds the rolling body 3 so that it can roll and move integrally, is capable of reciprocating within a certain operating range, is biased to one side in the reciprocating direction within the operating range, and is integrally connected to the injection port 2.

[0018] The wafer separation device 1 also has a stacking direction feed device 6 that moves a wafer stack 5 made up of a plurality of sliced ​​stacked wafers closer to the rolling elements 3 in the stacking direction. The stacking direction feed device 6 is, for example, configured with a transfer stage that transfers the wafer stack 5 to one side in the stacking direction toward the rolling elements 3.

[0019] In this embodiment, the stacking direction is the vertical direction, and the one side in the stacking direction is the vertically upward direction. Note that the stacking direction is not limited to the vertical direction, and may be, for example, a direction intersecting the vertical direction.

[0020] Furthermore, the wafer separation device 1 has a transport direction feed device 7 that transports the outermost wafer 5a, which contacts the rolling elements 3 on the one side in the stacking direction of the wafer stack 5, in a transport direction that intersects (preferably perpendicular to) the stacking direction after separation. Here, the outermost wafer 5a is the wafer positioned outermost in the stacking direction of the wafers, based on the position where the wafer stack 5 contacts the transport direction feed device 7, and refers to the wafer to be separated from the wafer stack 5 when the wafers are sent to the cleaning process.

[0021] The ejection port 2 is configured as, for example, a nozzle. The ejection port 2 ejects fluid supplied from an external fluid supply unit (not shown). The fluid ejected from the ejection port 2 is not particularly limited, and may be, for example, a liquid such as water or cleaning liquid, or a gas. The biasing force that biases the holder 4 to one side in the reciprocating movement direction is gravity. Note that the biasing force is not limited to gravity, and may be configured to use, for example, the elastic force of a spring.

[0022] The rolling elements 3 are configured by rollers that can rotate around a first rotation axis O1. The rolling elements 3 are not limited to rollers, and may be configured by balls, for example. However, from the viewpoint of suppressing damage to the wafer due to contact with the rolling elements 3, it is preferable to use rollers that make line contact rather than point contact. The first rotation axis O1 of the roller extends in a direction that intersects (preferably perpendicular to) the stacking direction and intersects (preferably perpendicular to) the transport direction.

[0023] In order to prevent damage to the wafer due to contact with the rolling element 3, the rolling element 3 may be configured so that the contact surface with the wafer is made of an elastic material, or so that a brush is provided on the outer surface of the roller and the rolling element 3 comes into contact with the wafer via the brush.

[0024] The holder 4 holds the nozzle 2 and the rolling elements 3. The holder 4 has a main body 4a, a nozzle holder 4b that holds the nozzle 2, and a rolling element holder 4c that holds the rolling elements 3. The main body 4a is rotatably connected to a housing (not shown) at a second rotation axis O2 and is a member that extends from the second rotation axis O2 toward approximately the transport direction. The second rotation axis O2 of the holder 4 is located vertically above the stacking direction feed device 6 and on the opposite side of the transport direction. The second rotation axis O2 extends in a direction that intersects (preferably perpendicular to) the stacking direction and intersects (preferably perpendicular to) the transport direction. Here, the "approximate transport direction" refers to a direction whose vector components include the direction in which the wafers are transported.

[0025] The nozzle holder 4b is a member extending vertically downward from the main body 4a, which extends approximately in the transport direction. The rolling element holder 4c is a member of the main body 4a, which extends approximately in the transport direction, that extends vertically downward from a position closer to the transport stage than the nozzle holder 4b. The nozzle 2 is held at a position lower than the rolling elements 3, and is positioned so that when the rolling elements 3 come into contact with the edge surface 5a1 of the outermost wafer 5a in the wafer stack 5, the nozzle 2 can spray fluid onto the boundary between the outermost wafer 5a and the other wafers.

[0026] The holder 4 is capable of reciprocating within the operating range (for example, ±25° from the horizontal) by rotation about the second rotation axis O2. With this configuration, the reciprocating operation of the holder 4 can be achieved with a simple structure. However, the holder 4 is not limited to this configuration, and may be configured to reciprocate within the operating range by translational operation using a slide mechanism or the like.

[0027] The transport direction feed device 7 is composed of a feed roller that can rotate around a third rotation axis O3. The feed roller is located on the transport stage. As the wafer stack 5 placed on the transport stage is transported in the stacking direction, the outermost wafer 5a comes into contact with the feed roller at its end surface 5a1. The feed roller, while in contact with the outermost wafer 5a, is rotated at a predetermined timing by a drive mechanism composed of, for example, a motor and a computer, thereby transporting the outermost wafer 5a in the transport direction. Note that the transport direction feed device 7 may be composed of something other than a feed roller. The third rotation axis O3 of the feed roller extends in a direction that intersects (preferably perpendicular to) the stacking direction and also intersects (preferably perpendicular to) the transport direction.

[0028] In order to prevent damage to the wafer due to contact with the feed roller, the feed roller may be configured so that the contact surface with the wafer is made of an elastic material, or a brush may be provided on the outer surface of the feed roller so that the feed roller comes into contact with the wafer via the brush.

[0029] The wafer separation device 1 can perform a wafer separation method including: an ejection nozzle moving step in which the ejection nozzle 2 is moved to a position corresponding to the position of the end face 5a1 of the outermost wafer 5a by abutting the rolling element 3 against the end face 5a1 on one side in the stacking direction of the outermost wafer 5a; a separation step in which the outermost wafer 5a is separated by ejecting a fluid from the ejection nozzle 2 moved by the ejection nozzle moving step, thereby causing the fluid to flow between the outermost wafer 5a and other wafers; and a transport step in which the outermost wafer 5a separated by the separation step is moved in a transport direction intersecting the stacking direction.

[0030] A wafer separation method using the wafer separation apparatus 1 will be described below with reference to FIGS.

[0031] First, in the nozzle movement step, the rolling body 3 is brought into contact with the nozzle side portion of the end face 5a1 of the outermost wafer 5a (hereinafter, for ease of explanation, this portion will also be referred to as the "injection side portion", and the opposite portion will also be referred to as the "transport side portion").

[0032] 1, a wafer stack 5 obtained by slicing a semiconductor ingot is placed on a transfer stage of a stacking direction feed device 6. At this time, the wafer stack 5 is free of sludge or the like, and the end faces 5a1 of the outermost wafers 5a are horizontally spread.

[0033] The stacking direction feed device 6 transports the wafer stack 5 toward the transport direction feed device 6 toward one side in the stacking direction (here, vertically upward). The wafer stack 5 transported to one side in the stacking direction first contacts the rolling elements 3. The rolling elements 3 contact the outermost wafer 5a at an end face 5a1 of the outermost wafer 5a on one side in the stacking direction. At this time, the holder 4 is positioned at the lowest position within its operating range due to its own weight.

[0034] The stacking direction feed device 6 continues to transport the wafer stack 5 to one side in the stacking direction even after the wafer stack 5 contacts the rolling elements 3. At this time, the wafer stack 5 pushes the rolling elements 3, and the holder 4 that holds the rolling elements 3 rotates about the second rotation axis O2, so that the rolling elements 3, the holder 4 that holds the rolling elements 3, and the injection nozzle 2 connected to the holder 4 are displaced as a unit in the stacking direction.

[0035] Because the movement of the rolling element 3 is a rotational movement about the second rotation axis O2, the rolling element 3 also displaces in the transport direction while coming into contact with the end face 5a1 of the outermost wafer 5a as it displaces in the stacking direction. By rotating the rolling element 3 about the first rotation axis O1 as it displaces in the transport direction, it is possible to prevent the rolling element 3 from damaging the end face 5a1 of the outermost wafer 5a.

[0036] 2, the stacking direction feed device 6 transports the wafer stack 5 to a height (hereinafter referred to as the reference height) at which the end face 5a1 of the outermost wafer 5a abuts against the feed roller. As the wafer stack 5 moves to the reference height, the injection nozzle 2 moves further.

[0037] Here, the separation point is defined as a portion of the boundary surface between the outermost wafer 5a and the other wafers that is closest to the ejection nozzle 2. The position of the ejection nozzle 2 and the angle at which the ejection nozzle 2 ejects the fluid are not particularly limited as long as the fluid ejected from the ejection nozzle 2 hits the separation point, but from the perspective of smoothly transporting the outermost wafer 5a in the transport direction, it is preferable that the ejection nozzle 2 be located at the same height as the separation point and be set to eject the fluid horizontally.

[0038] In the separation step, the jet nozzle 2 jets fluid toward the separation point to separate the outermost wafer 5 a from the wafer stack 5 .

[0039] In the transport step, the feed rollers of the transport direction feed device 7 rotate to transport the outermost wafer 5a in the transport direction.

[0040] Next, as shown in Fig. 3, when the outermost wafer 5a is tilted so that the separation point of the wafer stack 5 is located on one side in the stacking direction (i.e., vertically upward) relative to the opposite side due to the sludge 8 getting caught in the wafer stack 5, the rolling elements 3 are pushed up higher than when the end faces 5a1 of the outermost wafers 5a extend horizontally. As a result, compared to when the outermost wafers 5a are not tilted as shown in Fig. 2, the injection port 2 can be rotated integrally with the rolling elements 3 on the one side in the stacking direction around the second rotation axis O2.

[0041] Therefore, when the injection side portion of the end face 5a1 of the outermost wafer 5a is closer to one side in the stacking direction, that is, when the separation point is closer to one side in the stacking direction, the injection port 2 can be driven to the one side in the stacking direction via the rolling elements 3 and the holder 4. As a result, by injecting fluid from the injection port 2 in the separation step, the fluid can be more reliably caused to flow between the outermost wafer 5a and the other wafers.

[0042] Furthermore, even if the outermost wafer 5a is tilted such that the transport side portion of the end face 5a1 of the outermost wafer 5a is positioned on one side of the stacking direction relative to the injection side portion due to sludge 8 getting caught in the wafer stack 5, as shown in Figure 4, the rolling body 3 comes into contact with the injection side portion of the end face 5a1 of the outermost wafer 5a, and the injection port 2 can be rotated integrally with the rolling body 3 to the other side of the stacking direction (i.e., vertically downward) around the second rotation axis O2, compared to when the outermost wafer 5a is not inclined as shown in Figure 2.

[0043] Therefore, when the jetting side portion of the end face 5a1 of the outermost wafer 5a is closer to the other side in the stacking direction, that is, when the portion between the outermost wafer 5a and the other wafers into which the fluid jetted from the jetting port 2 should flow is closer to the other side in the stacking direction, the jetting port 2 can be driven to the other side in the stacking direction via the rolling elements 3 and the holder 4. As a result, by jetting the fluid from the jetting port 2 in the separation step, the fluid can be more reliably flowed between the outermost wafer 5a and the other wafers.

[0044] Note that the same operation of the ejection nozzle 2 as described above may be achieved by bringing the rolling elements 3 into contact with the transport-side portion of the end face 5a1 of the outermost wafer 5a in the ejection nozzle moving step by changing the arrangement of the second rotation axis O2 and the shape or structure of the holder 4. However, it is preferable to bring the rolling elements 3 into contact with the ejection-side portion of the end face 5a1 of the outermost wafer 5a in the ejection nozzle moving step as described above, because this makes it easier to achieve stable and accurate operation of the ejection nozzle 2.

[0045] In the transport step, the outermost wafer 5a separated in the separation step is moved in the transport direction by the transport direction feed device 7. At this time, the rolling elements 3 are capable of rolling relative to the holder 4, and therefore the rolling elements 3 can roll following the edge surface 5a1 of the outermost wafer 5a moving in the transport direction, thereby preventing damage caused by contact between the edge surface 5a1 of the outermost wafer 5a and the rolling elements 3.

[0046] A detection unit may be provided that detects, for example, by a sensor, a transport failure in which the outermost wafer 5a does not move in the transport direction due to a separation failure, and if the detection unit detects a transport failure in the transport step, the feed roller may be operated to repeatedly rotate forward and backward. In this case, even if the outermost wafer 5a repeatedly moves back and forth in the transport direction due to the repeated forward and backward rotation of the feed roller, damage to the end face 5a1 of the outermost wafer 5a can be suppressed by the following movement of the rolling elements 3.

[0047] The wafer separation device 1 transports the separated outermost wafer 5a in the transport direction using the transport direction feed device 7, and then uses the stacking direction feed device 6 to bring the other wafer (the next wafer stack 5 to be separated) and the rolling body 3 closer to each other in the stacking direction and bring them into contact, and then repeats the separation and transportation of the outermost wafer 5a in the manner described above.

[0048] The present invention is not limited to the above-described embodiment, and various modifications can be made without departing from the spirit and scope of the present invention.

[0049] Therefore, the wafer separation device 1 of the above-described embodiment can be modified as long as it is a wafer separation device 1 that has an injection port 2 for injecting a fluid, a rolling body 3, and a holder 4 that holds the rolling body 3 so that it can roll and move integrally, is capable of reciprocating motion, is biased to one side in the reciprocating motion direction, and is integrally connected to the injection port 2.

[0050] Furthermore, the wafer separation method of the above-described embodiment can be modified as long as it is a wafer separation method using the wafer separation device 1 and includes: an ejection nozzle moving step in which the ejection nozzle 2 is moved in accordance with the position of the end face 5a1 of the outermost wafer 5a included in the wafer stack 5 by abutting the rolling element 3 against the end face 5a1 in the stacking direction of the outermost wafer 5a; a separation step in which the outermost wafer 5a is separated by ejecting a fluid from the ejection nozzle 2 moved in the ejection nozzle moving step, thereby causing the fluid to flow between the outermost wafer 5a and the other wafers; and a transport step in which the outermost wafer 5a separated in the separation step is moved in a transport direction intersecting the stacking direction.

[0051] Furthermore, the wafer separation method of the above-described embodiment can be applied to the slicing process in the manufacture of silicon wafers, and can be used in the stage of separating and cleaning the sliced ​​wafers. This can prevent cracking and scratches on the wafers during the silicon wafer slicing process, suppressing poor wafer separation and improving production efficiency. Furthermore, the silicon wafers obtained in this manner can be subjected to processes typically used in silicon wafer manufacture, such as chamfering, planarization (lapping, etc.), polishing, and cleaning, to manufacture silicon wafers. [Explanation of symbols]

[0052] 1. Wafer separation device 2 injection port 3 Rolling elements 4 Holding body 4a Main body 4b Holding part 4c Rolling element retainer 5 Wafer stack 5a Outermost wafer 5a1 End face 6. Stacking direction feed device 7. Conveying direction feed device 8. Sludge O1 First rotation axis O2 Second rotation axis O3 Third rotation axis

Claims

1. an injection port for injecting a fluid; A rolling element; a holder that holds the rolling elements so that they can roll and move together, is reciprocatingly movable, is biased to one side in the reciprocating direction, and is integrally connected to the injection port.

2. 2. The wafer separation device according to claim 1, wherein the holder is reciprocally movable by a rotational motion.

3. The wafer separation device according to claim 1 , wherein the rolling elements are rollers.

4. A wafer separation method using the wafer separation apparatus according to any one of claims 1 to 3, an ejection nozzle moving step of moving the ejection nozzle in accordance with a position of the end face of the outermost wafer by bringing the rolling element into contact with the end face in the stacking direction of the outermost wafer included in the wafer stack; a separation step of injecting a fluid from the injection port moved in the injection port moving step, thereby causing the fluid to flow between the outermost wafer and other wafers, thereby separating the outermost wafer; a transport step of moving the outermost wafer separated by the separating step in a transport direction intersecting the stacking direction.

5. 5. The wafer separation method according to claim 4, wherein in the ejection port moving step, the rolling elements are brought into contact with a portion of the end face of the outermost wafer on the ejection port side.

6. The wafer separation method according to claim 4 is used, The method for producing a silicon wafer, wherein the wafer is a silicon wafer.

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