JP2014058038A - Wafer edge processing apparatus and edge processing method thereof - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a wafer edge processing apparatus carrying out high-accuracy edge shape processing of a wafer by using a polishing tape, and its edge processing method.SOLUTION: A wafer edge processing apparatus includes four carrying rollers 71, 72, 73 and 74, two guide rollers 75 and 76 and a cylinder 77 arranged within a nearly quadrilateral figure with the four carrying rollers 71, 72, 73 and 74 as apices and having a movable roller 78, in a polishing head 52. A polishing tape 51 is gripped with a combination of the guide roller 75 and the carrying roller 72 and a combination of the guide roller 76 and the carrying roller 73, respectively, in a movable way. The cylinder 77 causes the polishing tape 51 to protrude toward an edge part of a wafer, and the polishing tape 51 is brought into contact with the edge part of the wafer in nearly point contact.

Description

  The present invention relates to a wafer edge processing apparatus that processes the edge of a wafer such as silicon, which is a material of a semiconductor element, and more particularly to a wafer edge processing apparatus that performs chamfering processing of a wafer edge.

  An ingot such as silicon, which is a material of a semiconductor element, is cut into a thin wafer by a slicing machine. The wafer that has been cut has an edge shape on the outer periphery of the wafer (the outer periphery and the end surface of the wafer are substantially perpendicular to each other), so chipping (small chipping) and cracking are likely to occur due to slight impact on the outer periphery of the wafer. Become. Therefore, the wafer edge is chamfered using a chamfering grindstone or the like before lapping the wafer end surface cut by the slicing machine with the lapping apparatus.

  Moreover, in the conventional wafer edge processing apparatus, there exist some which chamfer a wafer edge by paying out, for example, a polishing tape instead of a chamfering grindstone (Patent Documents 1 and 2).

JP 2009-18363 A JP 2006-303112 A

  However, as shown in FIG. 9, in the polishing unit 101 of the wafer edge processing apparatus using the conventional polishing tape 100, the polishing tape 100 is pressed against the edge portion, and the polishing tape 100 is fed out and backed up by the plate 102. Thus, since the wafer edge shape is simply processed by the pressing angle of the polishing tape 100 and the work (wafer) 103 being put in and out, it is difficult to precisely control the processing of the wafer edge. That is, in this kind of wafer edge processing apparatus 101, the contact between the wafer 103 to be processed and the polishing tape 100 is only a substantially line contact, and a precise edge R shape (chamfering) cannot be formed. In addition, there is a problem that “more” occurs, and there is a problem that precise machining cannot be performed.

  Also, in the contouring process using a grindstone, the shape of the grindstone changes due to diameter fluctuations due to life (grinding wheel life) because a fixed grindstone is used. As a result, the quality of roughness changes. In other words, when using a wafer edge processing apparatus using a grindstone, the abrasive grains fall and the machined surface roughness changes depending on the number of uses. Similarly, the grindstone attaches and detaches and the shape changes depending on the number of uses. Truing and dressing are performed in order to extend the (grinding wheel life). However, when these are performed, there is a problem that the diameter of the grinding wheel changes and the position of the machine needs to be adjusted.

  The present invention has been made in view of such circumstances, and an object of the present invention is to provide a wafer edge processing apparatus and an edge processing method thereof capable of performing highly accurate edge shape processing in wafer edge processing using a polishing tape. And

  In order to achieve the above object, a wafer edge processing apparatus according to the first aspect of the present invention includes a polishing table that polishes an end portion of a wafer by bringing a mounting table on which the wafer is mounted and a polishing tape into contact with each other. And a moving means for moving the polishing unit relative to the mounting table, wherein the polishing unit is a point contact that causes the polishing tape to abut on the end of the wafer by a substantially point contact. A contact means is provided.

  According to this aspect, the polishing unit that polishes the end portion of the wafer by bringing the polishing tape into contact includes the point contact abutting means for bringing the polishing tape into contact with the end portion of the wafer by substantially point contact. Thereby, in wafer edge processing using a polishing tape, highly accurate edge shape processing can be performed.

  In the wafer edge processing apparatus according to the second aspect of the present invention, in the first aspect, the polishing unit further includes a line contact abutting means that abuts the polishing tape on the end of the wafer in a substantially line contact.

  The wafer edge processing apparatus according to a third aspect of the present invention is the wafer edge processing apparatus according to the first aspect or the second aspect, wherein the polishing unit is in contact with the polishing tape along the edge of the wafer in a plane including the rotation axis of the mounting table. Contact position changing means for changing

  In the wafer edge processing apparatus according to the fourth aspect of the present invention, in the third aspect, the contact position changing means makes the polishing tape contact the edge of the wafer while slightly vibrating the polishing tape.

  A wafer edge processing method according to a fifth aspect of the present invention includes a mounting table that can be rotated by mounting a wafer, a polishing unit that polishes an end portion of the wafer by contacting a polishing tape, and the polishing unit as a mounting table. A wafer processing method of a wafer edge processing apparatus comprising a moving means that moves relative to the wafer, and polishing the edge of the wafer by bringing the polishing tape into contact with the edge of the wafer in a substantially point contact manner. A point contact contact step.

  The wafer edge processing method according to a sixth aspect of the present invention includes a line contact contact step of polishing the edge of the wafer by bringing the polishing tape into contact with the edge of the wafer in substantially line contact in the fifth aspect. In addition.

  The wafer edge processing method according to a seventh aspect of the present invention provides the wafer edge processing method according to the fifth aspect or the sixth aspect, wherein the contact position of the polishing tape is changed along the edge of the wafer in the plane including the rotation axis of the mounting table. A position change step is further provided.

  In the wafer edge processing method according to the eighth aspect of the present invention, in the seventh aspect, in the contact position changing step, the polishing tape is brought into contact with the end portion of the wafer while the polishing tape is slightly vibrated.

  According to the present invention, it is possible to perform highly accurate edge shape processing in wafer edge processing using a polishing tape.

The figure which shows the structure of the grinding | polishing apparatus which concerns on embodiment of this invention. A first enlarged view showing a main part of the polishing head part of FIG. A second enlarged view showing the main part of the polishing head part of FIG. 3 is an enlarged view showing the movable roller of FIG. Sectional drawing which shows the AA line cross section of FIG. The figure explaining the line contact contact process which performs the line contact edge process by the grinding | polishing head part of the state of FIG. The figure explaining the point contact contact process which performs the point contact edge process by the grinding | polishing head part of the state of FIG. The figure which shows the modification of the point contact edge process by the grinding | polishing head part of the state of FIG. Figure showing a conventional polishing unit

  Hereinafter, a wafer edge processing apparatus and an edge processing method thereof according to the present invention will be described in detail with reference to the accompanying drawings.

  FIG. 1 is a diagram showing a configuration of a polishing apparatus according to an embodiment of the present invention. As shown in FIG. 1, a polishing apparatus 1 as a wafer edge processing apparatus according to this embodiment includes a wafer stage 3 as a wafer table unit for holding a wafer 2 and an upper surface (wafer holding surface) of the wafer stage 3. Wafer stage moving mechanism 4 for moving in a direction parallel to the wafer stage, edge polishing unit 5 as a polishing tape unit for polishing the edge portion of wafer 2 held on wafer stage 3, and edge polishing unit 5 A polishing moving mechanism 6 for moving the edge portion of the wafer 2 held on the wafer stage 3 is provided.

  The wafer stage moving mechanism 4 has a shaft base 11 that rotatably supports the cylindrical member 10, a movable part 12 that can move integrally with the shaft base 11, and an upper surface that is parallel to the upper surface of the wafer stage 3. And a support 14 that is supported by the base 13 so as to be movable.

  The movable portion 12 is movable on the upper surface of the base 13 in the direction indicated by the arrow Y parallel to the upper surface of the wafer stage 3. Further, the cylindrical member 10 of the shaft base 11 is configured to be rotatable about a β axis orthogonal to the upper surface of the wafer stage 3 as a rotation axis.

  The edge polishing unit 5 includes a polishing head portion 52 as an edge contact portion that contacts and presses the polishing tape (band-shaped polishing member) 51 against the edge portion of the wafer 2, and a polishing tape that sends the polishing tape 51 to the polishing head portion 52. A feed mechanism 53. The polishing tape feeding mechanism 53 includes a feeding bobbin 54 as a tape feeding unit that feeds the polishing tape 51 to the polishing head unit 52, and a winding bobbin as a tape winding unit that winds up the polishing tape 51 fed to the polishing head unit 52. 55 and a rotation mechanism (not shown) for rotating the take-up bobbin 55. As the polishing tape 51, a polishing tape in which abrasive grains of abrasive particles are applied to a base film on one side serving as a polishing surface can be used.

  The polishing moving mechanism 6 includes a shaft base 61 having a cylindrical member 60 that holds the edge polishing unit 5 including the polishing head portion 52 and the polishing tape feed mechanism 53, a movable portion 62 that can move integrally with the shaft base 61, and a movable portion. A shaft base 63 that supports the portion 62 and a movable portion 64 that can move integrally with the shaft base 63 are provided.

  The movable portion 64 is movable on the upper surface of the base 13 in the direction indicated by the arrow X perpendicular to the Y direction parallel to the upper surface of the wafer stage 3. The movable portion 62 is movable in the direction indicated by the arrow Z in the longitudinal axis direction of the β axis perpendicular to the XY plane. Further, the polishing head portion 52 is rotatable around an α axis having a longitudinal axis in the X direction.

  FIG. 2 is a first enlarged view showing a main part of the polishing head part of FIG. As shown in FIG. 2, the polishing head unit 52 is wound through four conveying rollers 71, 72, 73, and 74 arranged at the apex position of a substantially square when the winding bobbin 55 winds up the polishing tape 51. The polishing tape 51 fed from the feed bobbin 54 and positioned on the transport rollers 72 and 73 is configured to come into contact with the edge portion of the wafer 2 by substantially line contact. The polishing tape 51 positioned on the transport rollers 72 and 73 is held by guide rollers 75 and 76 so as to be movable by the guide roller 75 and the transport roller 72, and the guide roller 76 and the transport roller 73, respectively. This prevents “wrinkles” and “more” from occurring on the polishing tape 51.

  The line contact contact means includes a guide roller 75, a conveyance roller 72, a guide roller 76, a conveyance roller 73 and a polishing tape 51.

  The polishing head unit 52 is held inside a substantially square shape having four conveying rollers 71, 72, 73, 74 as apexes so as to be movable by the guide roller 75 and the conveying roller 72, and the guide roller 76 and the conveying roller 73, respectively. A cylinder 77 having a movable roller 78 at its tip is provided for projecting the polished polishing tape 51 toward the edge portion of the wafer 2 and bringing the polishing tape 51 into contact with the edge portion of the wafer 2 by substantially point contact. .

  The point contact contact means includes a guide roller 75, a transport roller 72, a guide roller 76, a transport roller 73, a movable roller 78, a cylinder 77, and a polishing tape 51.

  FIG. 3 is a second enlarged view showing the main part of the polishing head part of FIG. As shown in FIG. 3, in the polishing head portion 52, when the polishing tape 51 is brought into contact with the edge portion of the wafer 2 by substantially point contact, the cylinder 77 moves toward the edge portion of the wafer 2, The movable roller 78 provided at the tip is pressed from the inner side surface (surface without abrasive particles) of the polishing tape 51. As a result, the polishing tape 51 that is movably held by the guide roller 75 and the transport roller 72, and the guide roller 76 and the transport roller 73, respectively, protrudes toward the edge portion of the wafer 2, and the polishing tape 51 is moved to the wafer. The two edge portions are brought into contact with each other by substantially point contact.

  4 is an enlarged view showing the movable roller of FIG. 3, and FIG. 5 is a cross-sectional view showing a cross section taken along line AA of FIG. As shown in FIGS. 4 and 5, the movable roller 78 has a rotation shaft 80 that feeds the polishing tape 51 as a central axis, the central axis is the maximum diameter in the axial direction, and the diameter is reduced from the center toward both ends in the axial direction. The central portion 81 having the largest barrel shape in the axial direction comes into contact with the edge portion of the wafer 2 by substantially point contact.

  The chamfering processing of the edge portion of the wafer 2 by the polishing head unit 52 in the polishing apparatus 1 of the present embodiment configured as described above will be described with reference to FIGS. 6 is a diagram for explaining a line contact abutting process for performing line contact edge processing by the polishing head portion in the state of FIG. 2, and FIG. 7 is a point contact abutting for performing point contact edge processing by the polishing head portion in the state of FIG. It is a figure explaining a process.

(1) Line contact contact process:
In the line contact contact step by the polishing apparatus 1 of the present embodiment, first, the cylinder 77 of the polishing head unit 52 is set to the state shown in FIG. Then, as shown in FIG. 6, the polishing head unit 52 applies the polishing tape 51 positioned on the transport rollers 72 and 73 to the edge portion of the wafer 2 in a substantially line contact from the position P 0 positioned in the radial direction of the wafer 2. Make contact. Subsequently, the polishing head unit 52 is rotated about the α axis, and the polishing tape 51 positioned on the transport rollers 72 and 73 is brought into contact with the edge portion of the wafer 2 from the positions P1 and P2 through a substantially line contact. As a result, the polishing head unit 52 roughly chamfers the edge portion of the wafer 2, and a chamfering function can be realized.

(2) Point contact contact process:
In the point contact contact step by the polishing apparatus 1 of this embodiment, first, the cylinder 77 of the polishing head unit 52 is in the state shown in FIG. 3 (the guide roller 75 and the transport roller 72, and the guide roller 76 and the transport roller 73, respectively. The polishing tape 51 held so as to be movable protrudes toward the edge portion of the wafer 2). Then, as shown in FIG. 7, the polishing head unit 52 applies the polishing tape 51 positioned on the transport rollers 72 and 73 to the edge portion of the wafer 2 by a substantially point contact from the position P 0 positioned in the radial direction of the wafer 2. Make contact. Subsequently, the polishing head 52 is rotated from the position P0 to the position P1 about the α axis, and the polishing tape 51 positioned on the transport rollers 72 and 73 is continuously contacted with the edge portion of the wafer 2 substantially at point contact. Make contact. Similarly, the polishing head 52 is rotated from the position P0 to the position P2 about the α axis, and the polishing tape 51 positioned on the transport rollers 72 and 73 is continuously contacted with the edge portion of the wafer 2 substantially at point contact. Make contact. As a result, the polishing head unit 52 finely chamfers the edge portion of the wafer 2, and a chamfering polishing function can be realized.

  In this embodiment, the polishing apparatus 1 does not just press the polishing tape 51 during polishing, but moves the positioning shaft (α-axis) slightly at high speed to vibrate, thereby causing the flow of abrasive grains not only in one direction. Roughness is improved by applying a hitting effect.

  As described above, the polishing apparatus 1 of the present embodiment can obtain the following effects.

  (Effect 1) In edge processing of the wafer 2 using the polishing tape 51, highly accurate edge shape processing can be performed.

  (Effect 2) Since the edge portion of the wafer 2 is chamfered by the polishing tape 51, there is no change in shape and roughness as in the case of using a grindstone, and there is no need for truing or dressing.

  (Effect 3) The polishing tape 51 used for the chamfering polishing function is used only at the center of the tape. As a result, the tape is not wasted by rewinding the polishing tape 51 and shifting the polishing tape 51.

  (Effect 4) One polishing head unit 52 can have both a processing function and a polishing function.

  (Effect 5) Since the movable roller 78 has a barrel shape, the polishing tape 51 positioned on the transport rollers 72 and 73 can be brought into contact with the edge portion of the wafer 2 by substantially point contact. Wrinkles and influences are eliminated and high-precision machining is possible.

  In the present embodiment, the polishing head portion 52 is rotated about the α axis even in the point contact contact step. However, as shown in FIG. You may make it perform a point contact contact process by moving the grinding | polishing head part 52 to a Z direction (refer FIG. 1).

  As described above, the wafer edge processing apparatus and the edge processing method of the present invention have been described in detail. However, the present invention is not limited to the above examples, and various improvements and modifications are made without departing from the gist of the present invention. Of course.

DESCRIPTION OF SYMBOLS 1 ... Polishing apparatus, 2 ... Wafer, 3 ... Wafer stage, 4 ... Wafer stage moving mechanism, 5 ... Polishing unit, 6 ... Polishing moving mechanism, 51 ... Polishing tape, 52 ... Polishing head part, 71, 72, 73, 74 ... Conveying rollers, 75, 76 ... Guide rollers, 77 ... Cylinders, 78 ... Movable rollers

Claims (8)

A mounting table on which a wafer can be mounted and rotated;
A polishing portion for polishing an end portion of the wafer by contacting a polishing tape;
A wafer edge processing apparatus comprising: moving means for moving the polishing unit relative to the mounting table;
The polishing unit is a wafer edge processing apparatus comprising point contact abutting means for abutting the polishing tape to an end portion of the wafer by substantially point contact.   2. The wafer edge processing apparatus according to claim 1, wherein the polishing unit further includes a line contact abutting unit that abuts the polishing tape on a substantially linear contact with an end of the wafer. 3.   3. The wafer edge according to claim 1, wherein the polishing unit includes contact position changing means for changing a position where the polishing tape contacts along an end portion of the wafer in a plane including a rotation axis of the mounting table. Processing equipment.   The wafer edge processing apparatus according to claim 3, wherein the contact position changing unit makes the polishing tape contact the end portion of the wafer while slightly vibrating the polishing tape. A mounting table that can be rotated by mounting a wafer; a polishing unit that polishes an end of the wafer by contacting a polishing tape; and a moving unit that moves the polishing unit relative to the mounting table. A wafer processing method of a wafer edge processing apparatus comprising:
A wafer edge processing method comprising a point contact contact step of polishing the end portion of the wafer by bringing the polishing tape into contact with the end portion of the wafer by substantially point contact.   6. The wafer edge processing method according to claim 5, further comprising a line contact contact step of polishing the end portion of the wafer by bringing the polishing tape into contact with the end portion of the wafer by substantially line contact.   7. The wafer edge processing method according to claim 5, further comprising a contact position changing step of changing a position where the polishing tape contacts along an end portion of the wafer in a plane including the rotation axis of the mounting table.   The wafer edge processing method according to claim 7, wherein in the contact position changing step, the polishing tape is brought into contact with an end portion of the wafer while minutely vibrating the polishing tape.

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