JP2005153130A - Chamfering method of wafer with orientation flat - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a chamfering method of a wafer with an orientation flat, not causing the sectional shape of a chamfering part to vary in each of the outer peripheral part, orientation flat straight part and orientation flat corner rounded part of the wafer to obtain a favorable chamfering shape. <P>SOLUTION: Between the straight part and the corner rounded part of the orientation flat, at least one part is chamfered with a grinding wheel groove different from a grinding wheel groove for chamfering the outer peripheral part of the wafer W, and chamfering is performed by grinding wheel grooves of shapes suitable for the outer peripheral part, the orientation flat straight part and the orientation flat corner rounded part of the wafer W, respectively, whereby even when chamfering is performed with the rotating shaft of the grinding wheel inclined at a designated angle in the tangential direction to the outer periphery of the wafer to obtain favorable surface roughness, the sectional shapes of the respective parts are not varied. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a method for chamfering a wafer, and more particularly to a method for chamfering a wafer with an orientation flat in a wafer such as a semiconductor device or an electronic component.

  A wafer such as silicon, which is a material for semiconductor devices and electronic components, is sliced from the ingot state with a slicing device such as an inner peripheral blade or a wire saw, and then the outer peripheral portion is prevented to prevent cracking or chipping of the peripheral edge. Chamfering is applied to By the way, orientation flats (abbreviations of orientation flats) are often formed on the outer circumferences of these wafers in order to easily determine the crystal orientation and align the wafers. And about these wafers, it is necessary to chamfer the orientation flat as well.

  Conventionally, in the chamfering of the peripheral edge of the wafer, in order to obtain a good surface roughness of the chamfered surface, it has been proposed to chamfer the chamfering grindstone by tilting the axis of the chamfering grindstone by a predetermined angle in the tangential direction of the outer periphery of the wafer ( For example, see Patent Document 1.)

According to this technique, the movement direction of the abrasive grains of the grindstone is oblique with respect to the rotation direction of the wafer, and the surface roughness of the processed surface is improved.
JP-A-5-152259

  However, in the chamfering method described in Japanese Patent Application Laid-Open No. 5-152259, the surface roughness of the processed surface is certainly improved, but the grindstone grooves in the outer peripheral portion of the wafer, the orientation flat linear portion, and the orientation flat corner R portion, respectively. Since the contact area of each part changes, there is a problem that the chamfer width in each part is different and the cross-sectional shape changes.

  The present invention has been made in view of such circumstances, and in chamfering of a wafer with an orientation flat, the cross-sectional shape of the chamfered portion does not change in each part of the outer peripheral portion of the wafer, the orientation flat linear portion, and the orientation flat corner R portion. An object of the present invention is to provide a method for chamfering a wafer with an orientation flat capable of obtaining a good chamfered shape.

  In order to achieve the object, the invention according to claim 1 is a method for chamfering a wafer with a grindstone groove formed on an outer periphery of a grindstone, wherein the orientation flat is a chamfering method for a wafer with an orientation flat. Among the straight portions and corner R portions, at least one of them is chamfered with a grindstone groove different from the grindstone groove for chamfering the outer peripheral portion of the wafer.

  According to the first aspect of the present invention, since the chamfering can be performed with the grindstone grooves having shapes suitable for the outer peripheral portion of the wafer, the orientation flat linear portion, and the orientation flat corner R portion, the rotation axis of the grindstone is set in the tangential direction of the outer periphery of the wafer Even if the chamfering process is performed at a predetermined angle, the cross-sectional shape of each part does not change.

The invention according to claim 2 is the invention according to claim 1, wherein the outer peripheral portion of the wafer is chamfered with a grindstone groove of a grindstone whose rotational axis is inclined in a tangential direction of the outer peripheral circle of the wafer,
The straight portion and the corner R portion of the orientation flat are chamfered by a grindstone groove of a grindstone having a rotation axis parallel to the rotation axis of the wafer.

  According to the invention of claim 2, since the orientation flat straight portion and orientation flat corner R portion are chamfered by a normal grindstone groove that is not inclined, a predetermined chamfering shape is obtained and matches the chamfering shape of the outer peripheral portion.

  According to a third aspect of the present invention, in the first aspect of the invention, the outer peripheral portion of the wafer and the linear portion of the orientation flat are made of a grindstone whose rotational axis is inclined in the tangential direction of the outer peripheral circle of the wafer. The corner R portion of the orientation flat is chamfered with a grindstone groove of a grindstone having a rotation axis parallel to the rotation axis of the wafer.

  According to the invention of claim 3, since the orientation flat corner R portion having a large change in the chamfering shape is chamfered by the grindstone groove of the rotation axis parallel to the rotation axis of the wafer, the efficiency of the chamfering shape is suppressed while suppressing the change as much as possible. Good processing can be performed.

  The invention according to claim 4 is the invention according to claim 2 or claim 3, wherein the rough grinding chamfering is chamfered by a grindstone groove of a grindstone having a rotation axis parallel to the rotation axis of the wafer, Only the fine grinding chamfering process is characterized by chamfering with a grindstone groove of a grindstone whose rotational axis is inclined in the tangential direction of the outer circumference circle of the wafer.

  According to the invention of claim 4, since only the chamfering of the outer periphery of the wafer or only the finishing chamfering of the outer periphery of the wafer and the linear flat portion of the wafer is precisely ground and chamfered with a grindstone having an inclined rotation axis, It is possible to prevent the mechanism from becoming complicated.

  According to a fifth aspect of the present invention, in the fourth aspect of the invention, the fine grinding chamfering grindstone having a rotation axis parallel to the rotation axis of the wafer is integrated with the rough grinding chamfering grindstone. Or mounted on the same rotary shaft as the rotary shaft of a grindstone for rough grinding chamfering.

  According to the invention of claim 5, the grinding wheel for fine grinding chamfering for finishing chamfering the orientation flat corner R portion or orientation flat straight portion and orientation flat corner R portion is manufactured integrally with the grinding stone for rough grinding chamfering processing or both. Are attached coaxially, the mechanism of the chamfering device is simplified.

  According to a sixth aspect of the present invention, in the invention according to any one of the second, third, fourth, or fifth aspect, the rotation axis is inclined in a tangential direction of the outer circumferential circle of the wafer. A grindstone to be chamfered and a grindstone to be chamfered with the rotation axis parallel to the rotation axis of the wafer were attached to the same rotation axis, and the rotation axis was inclined in the tangential direction of the outer circumference circle of the wafer. The chamfering process is performed by switching between a state and a state parallel to the rotation axis of the wafer.

  According to the invention of claim 6, since the rotation axis can be switched between a state parallel to the rotation axis of the wafer and a state inclined to the tangential direction of the outer circumference of the wafer, the number of grindstone spindles can be reduced. As a result, the range of applications for various processing methods is expanded.

  As described above, according to the method for chamfering a wafer with an orientation flat according to the present invention, it is possible to easily suppress changes in the chamfered cross-sectional shapes of the outer peripheral portion, the orientation flat linear portion, and the orientation flat corner R portion of the wafer.

  DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments of a method for chamfering an orientation flat wafer according to the present invention will be described below in detail with reference to the accompanying drawings. In each figure, the same number or symbol is attached to the same member.

  First, a wafer chamfering apparatus used in the method for chamfering a wafer with an orientation flat according to the present invention will be described. FIG. 1 is a front view showing a main part of the chamfering apparatus. The chamfering apparatus 10 includes a wafer feeding unit 20, a grindstone rotating unit 50, a wafer supply / storage unit (not shown), a wafer cleaning / drying unit, a wafer transfer unit, and a controller that controls operations of each part of the chamfering device.

  The wafer feeding unit 20 includes an X-axis base 21, two X-axis guide rails 22, 22, four X-axis linear guides 23, 23,..., A ball screw and a stepping motor mounted on the main body base 11. It has an X table 24 that is moved in the X direction in the figure by the X axis driving means 25.

  The X table 24 is moved in the Y direction in the figure by Y axis driving means comprising two Y axis guide rails 26, 26, four Y axis linear guides 27, 27,..., A ball screw and a stepping motor (not shown). A Y table 28 is incorporated.

  The Y table 28 is guided by two Z-axis guide rails 29 and 29 and four Z-axis linear guides (not shown), and is moved in the Z direction in the figure by a Z-axis driving means 30 comprising a ball screw and a stepping motor. Z table 31 is incorporated.

  The Z table 31 incorporates a θ-axis motor 32 and a θ spindle 33, and a wafer table 34 on which the wafer W is sucked and mounted is attached to the θ spindle 33. The wafer table 34 has a wafer table rotation axis CW. It is rotated in the θ direction in the figure as the center.

  Further, the upper surface of the wafer table 34 is a suction surface that communicates with a vacuum source (not shown), and a wafer W to be chamfered is placed and fixed by suction.

  A truing grindstone 41 used for truing a grindstone for chamfering the periphery of the wafer W is attached to the lower portion of the wafer table 34 concentrically with the wafer table rotation axis CW.

  By this wafer feeding unit 20, the wafer W and the truing grindstone 41 are rotated in the θ direction in the figure and are moved in the X, Y, and Z directions in the figure.

  The grindstone rotating unit 50 has an outer peripheral rough grinding wheel 52 attached thereto, an outer peripheral grindstone spindle 51 that is driven to rotate about an axis CH by an outer grindstone motor (not shown), and a turntable 53 disposed above the outer peripheral rough grinding grindstone 52. And a notch coarse spindle 60 and a notch coarse motor 62, a notch fine spindle 57, and a notch fine motor 59.

  An outer peripheral fine grinding wheel 55 which is a chamfering grindstone for finishing and grinding the outer periphery of the wafer W is attached to the outer peripheral fine spindle 54, a notch rough grinding wheel 61 is provided on the notch rough grinding spindle 60, and a notch fine grinding spindle 57 is provided on the notch fine grinding spindle 57. A notch precision grinding wheel 58, which is a notch chamfering grindstone for finish grinding the notch portion, is attached.

  As shown in FIG. 2, the outer peripheral rough grinding wheel 52 includes a master grindstone 52A having a truer master groove 52a, an orientation flat linear portion, and a corner R portion precision. An orientation flat linear portion having a grinding wheel groove 52d for grinding and a corner R portion fine grinding wheel 52D are bonded and fixed to form an integral structure of three grinding wheels.

  The outer peripheral rough grinding wheel 52B, the master grindstone 52A, the orientation flat linear portion and the corner R portion fine grinding wheel 52D may be individually attached to the same outer peripheral grindstone spindle 51 without forming a three-piece structure.

  The outer peripheral fine grinding wheel 55, the notch fine grinding wheel 58, and the notch coarse grinding wheel 61 are positioned at the processing positions by the rotation of the turntable 53.

  The outer peripheral precision spindle 54 is attached at the machining position so as to be switchable between a posture inclined by a predetermined angle in the X direction in FIG. 1 and a vertical posture. For this reason, when the outer periphery of the wafer W is chamfered by tilting the outer periphery of the wafer W by a predetermined angle in the X direction with the outer peripheral fine grinding wheel 55, the movement locus of the abrasive grains moves obliquely with respect to the rotation direction of the wafer W for grinding. it can.

  Hereinafter, a grinding method in which the movement locus of the abrasive grains is oblique with respect to the rotation direction of the wafer W will be referred to as helical grinding. In the case of helical grinding, the machined surface roughness is better than normal grinding.

  FIG. 3 shows a switching structure between a posture inclined by a predetermined angle in the X direction and a vertical posture of the outer peripheral grinding wheel 55. The outer peripheral precision grinding spindle 54 having the outer peripheral precision grinding wheel 55 and the orientation flat corner R portion precision grinding wheel 55 A attached to the tip is fixed to a spindle holder 63. The spindle holder 63 is supported by a block 64 attached to the turntable 53 via two hinge pins 65, 65 so as to be swingable in the X direction in the figure.

  On the other hand, an air cylinder 66 is swingably supported by a block 69 attached to the turntable 53 via a pin 68, and the tip of the cylinder shaft 66 A of the air cylinder 66 and the spindle holder 63 are rocked via a pin 67. It is connected freely.

  With such a support structure, the outer peripheral fine spindle 54 is switched between a vertical posture and a posture inclined by a predetermined angle α in the X direction in the figure by expansion and contraction of the air cylinder 66. Further, the inclination angle (predetermined angle) α is arbitrarily set by controlling the stroke of the air cylinder 66.

  In the present embodiment, the outer peripheral rough grinding stone 52B is a diamond bonded metal bond grindstone having a particle size of # 800. The orientation flat straight part and corner R part fine grinding wheel 52D is a resin bond grindstone of diamond abrasive grains having a diameter of 202 mm, and has a particle size of # 3000. Also, the master grindstone 52A for truer is a metal bond grindstone of diamond abrasive with a diameter of 202 mm, and has a particle size # 600.

  The peripheral grinding wheel 55 is a resin bond grindstone of diamond abrasive grains having a diameter of 50 mm, and has a particle size of # 3000. Also, the orientation flat corner R portion fine grinding wheel 55A mounted coaxially with the outer peripheral grinding wheel 55 is a resin bond grinding wheel of diamond abrasive grains having a diameter of 50 mm, and has a particle size of # 3000.

  The outer peripheral grinding wheel spindle 51 is a built-in motor driven spindle using a ball bearing and is rotated at a rotational speed of 8,000 rpm. Further, the outer peripheral precision spindle 54 is a built-in motor driven spindle using an air bearing and is rotated at a rotational speed of 35,000 rpm.

  Since the other components of the chamfering device 10 are generally well-known mechanisms, a detailed description is omitted.

  Next, a method for chamfering a wafer with an orientation flat using the chamfering apparatus 10 configured as described above will be described.

  First, the wafer W is attracted and fixed in a state of being centered on the wafer table 34, cut into the outer peripheral rough grinding wheel 52B that is sent in the Y direction and rotated, and rotated by θ to rough chamfer the peripheral portion. Rough grinding chamfering is performed by θ rotation and X and Y axis movement, and the orientation flat linear portion is rough grinding chamfering by X axis movement.

  Next, finish chamfering of each part. FIG. 4 is a conceptual plan view showing the procedure of finishing chamfering. As shown in FIG. 4, first, in a state where the outer peripheral precision grinding wheel 55 is inclined by a predetermined angle α, the wafer table 34 is raised to align the position of the wafer W in the Z direction with the grinding wheel groove of the outer peripheral precision grinding wheel 55. Next, θ rotation is started from the connection portion of the outer peripheral portion C of the wafer W with the orientation flat corner R portion OR, and the outer peripheral portion C is finely chamfered (FIGS. 4A and 4B). At this time, the helical grinding is such that the motion trajectory of the abrasive grains is oblique with respect to the rotation direction of the wafer W, and the processed surface roughness is improved as compared with normal grinding.

  Next, the wafer table 34 is lowered, and the position of the wafer W in the Z direction is aligned with the grindstone groove of the orientation flat linear portion and the corner R portion fine grinding wheel 52D. Then, the orientation flat corner R OR is finely chamfered by θ rotation of the wafer W and X and Y axis movements (FIG. 4C), and then the orientation flat linear part OF is finely chamfered by X axis movement of the wafer W ( 4 (d) and 4 (e)), finally, the opposite orientation flat corner R portion OR is chamfered by θ rotation of the wafer W and X and Y axis movement (FIG. 4 (f)).

  When simultaneously chamfering both front and back surfaces of the wafer W using the general-purpose grindstone, the chamfering process for one wafer W is completed. Moreover, when chamfering both front and back surfaces separately, the above steps are repeated.

  In this way, since the outer peripheral portion C of the wafer W is helically ground and the orientation flat straight portion OF and the orientation flat corner R portion OR are precisely chamfered with the grindstone groove of another grindstone, the cross-sectional shape of each portion does not change. Chamfering can be performed with a uniform cross-sectional shape.

  In the above-described embodiment, the outer peripheral portion C of the wafer W is helically ground by inclining the outer peripheral fine grinding wheel 55 in the tangential direction, and the orientation flat linear portion OF and the orientation flat corner R portion OF are chamfered by another vertical grinding stone. However, the outer peripheral portion C and the orientation flat linear portion OF may be helically ground with the inclined outer peripheral precision grinding stone 55, and only the orientation flat corner R portion OF having a large cross-sectional shape change may be chamfered with another vertical grinding stone.

  In this case, the outer periphery precision grinding wheel 55 and the orientation flat corner R portion precision grinding wheel 55A are attached to the outer periphery precision grinding spindle 54, and when the outer circumference portion C and the orientation flat linear portion OF are chamfered, the outer periphery precision grinding spindle 54 is inclined. When chamfering the orientation flat corner R portion, the outer peripheral precision spindle 54 is switched to a vertical posture and chamfered.

  Further, the outer peripheral fine grinding wheel 55, the orientation flat corner R portion fine grinding wheel 55A, and the orientation flat straight portion precision grinding dedicated grindstone (not shown) are mounted on the same rotating shaft tilt spindle, and the outer peripheral portion C of the wafer W, the orientation flat linear portion OF, The orientation flat corner R part OR may be chamfered with a dedicated grindstone groove so as to be chamfered with good surface roughness without causing a change in cross-sectional shape.

  In addition to the above, the outer peripheral fine grinding wheel 55, the orientation flat linear part and corner R part precision grinding wheel 52D, the orientation flat corner R part precision grinding wheel 55A, and the spindle tilt switching mechanism can be combined in various ways to cope with various needs. It is.

  In the above-described embodiment, the rough grinding chamfering process is performed with a vertical grindstone that does not incline, but helical grinding with the grindstone axis inclined may also be performed in the rough grinding chamfering process. Even in this case, the orientation flat corner R portion OR can be processed with a vertical grindstone to reduce the change in the chamfered cross-sectional shape.

The front view showing the chamfering apparatus used with the chamfering method of the wafer with an orientation flat which concerns on this invention Conceptual diagram showing a composite-type grinding wheel Sectional view showing grinding wheel shaft tilt mechanism Plan view showing chamfering procedure

Explanation of symbols

  DESCRIPTION OF SYMBOLS 10 ... Chamfering apparatus, 34 ... Wafer table, 52, 52B ... Peripheral rough grinding wheel, 52D ... Orient flat straight part and corner R part fine grinding wheel, 55 ... Peripheral fine grinding wheel, 55A ... Orient flat corner R part fine grinding wheel, α ... Inclination angle (predetermined angle), C ... outer peripheral part, OF ... Oriental flat line part, OR ... Oriental flat corner R part (corner R part), W ... Wafer

Claims (6)

A method of chamfering a wafer with a grindstone groove formed on the outer periphery of a grindstone, and in a chamfering method of a wafer with an orientation flat,
A chamfering method for a wafer with an orientation flat, characterized in that at least one of the linear portion and the corner R portion of the orientation flat is chamfered with a grindstone groove different from the grindstone groove for chamfering the outer peripheral portion of the wafer. . The outer peripheral portion of the wafer is chamfered with a grindstone groove of a grindstone whose rotation axis is inclined in a tangential direction of the outer peripheral circle of the wafer,
2. The wafer with an orientation flat according to claim 1, wherein the linear portion and the corner R portion of the orientation flat are chamfered by a grindstone groove of a grindstone having a rotation axis parallel to the rotation axis of the wafer. Chamfering method. The outer peripheral portion of the wafer and the linear portion of the orientation flat are chamfered with a grindstone groove of a grindstone whose rotational axis is inclined in a tangential direction of the outer peripheral circle of the wafer,
2. The method of chamfering a wafer with an orientation flat according to claim 1, wherein the corner R portion of the orientation flat is chamfered with a grindstone groove of a grindstone having a rotation axis parallel to the rotation axis of the wafer. . Rough grinding chamfering is chamfered with a grindstone groove of a grindstone having a rotation axis parallel to the rotation axis of the wafer,
4. A wafer with an orientation flat according to claim 2, wherein only the fine grinding chamfering is performed by chamfering with a grindstone groove of a grindstone whose rotational axis is inclined in a tangential direction of the outer circumferential circle of the wafer. Chamfering method.   A grindstone for fine grinding chamfering having a rotation axis parallel to the rotation axis of the wafer is manufactured integrally with a grindstone for rough grinding chamfering, or the same as the rotation axis of the grindstone for rough grinding chamfering The method for chamfering a wafer with an orientation flat according to claim 4, wherein the wafer is attached to a rotating shaft. A grindstone that is chamfered by inclining the rotational axis in the tangential direction of the outer peripheral circle of the wafer and a grindstone that is chamfered with the rotational axis parallel to the rotational axis of the wafer are attached to the same rotational axis. ,
The chamfering process is performed by switching between a state in which the rotation axis is inclined in a tangential direction of the outer peripheral circle of the wafer and a state parallel to the rotation axis of the wafer. Or chamfering a wafer with an orientation flat according to any one of 5 or 5.

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