JP5975839B2 - Grinding equipment - Google Patents

Description

  The present invention relates to a grinding apparatus for grinding a workpiece such as a semiconductor wafer or an optical device wafer.

  In the manufacturing process of a semiconductor device, a grid-like division planned line called street is formed on the surface of a wafer made of silicon or a compound semiconductor. Then, a device such as an IC or LSI is formed in each area partitioned by the division lines.

  These wafers are ground on the back by a grinding machine and thinned to a predetermined thickness, then cut along the streets by a cutting machine or a laser processing machine, and divided into individual chips. Manufactured. The semiconductor device manufactured in this way is widely used in various electric devices such as mobile phones and personal computers.

  With the thinning of semiconductor devices, there is a desire to grind wafers to 100 μm or less, for example. In order to reduce the thickness of the wafer without damaging it, it is necessary to perform rough grinding and finish grinding, and further, stress relief such as polishing is required to remove grinding distortion. For example, Japanese Patent Application Laid-Open No. 2005-153090 discloses an apparatus that enables a plurality of processes with a single processing apparatus.

  In the processing apparatus disclosed in this publication, four chuck tables are mounted on a turntable that rotates in a horizontal plane, and the wafer held on the chuck table is rotated to rotate the turntable, thereby providing a rough grinding processing region and finishing. It is positioned in each of the grinding area and the polishing area, enabling continuous processing on the wafer.

JP 2005-153090 A

  In recent years, semiconductor wafers have been increased in size, and a φ450 mm wafer has been developed in place of the current mainstream φ300 mm wafer. Although various processing devices for processing wafers cannot be denied as wafers become larger, there is a demand for downsizing the footprint (occupied space) as much as possible.

  In the processing apparatus described in the cited document 1, since four chuck tables are rotatably mounted on a turntable that rotates in a horizontal plane, in order to grind a φ450 mm wafer, A chuck table with a large diameter is required, and the turntable mounted with the chuck table has to be very large, and the footprint is inevitably large.

  The present invention has been made in view of the above points, and an object of the present invention is to provide a grinding apparatus that can reduce the footprint.

  According to the present invention, there is provided a grinding apparatus for grinding a workpiece, wherein the first holding means for rotatably holding the workpiece, a first spindle that is driven to rotate, and a tip of the first spindle are mounted. A first grinding means including a first grinding wheel including a first grinding wheel facing the workpiece held by the first holding means, and the first grinding means approaches and separates from the first holding means. A first machining area having a first movement means for moving in a direction, a second holding means for rotatably holding a workpiece, a second spindle that is driven to rotate, and a tip portion of the second spindle A second grinding means including a second grinding wheel including a second grinding wheel facing a workpiece held on the workpiece and held by the second holding means; and approaching the second grinding means to the second holding means Second moving means for moving in a direction away from the second moving means. A machining area; and a conveying means for conveying a workpiece from the first holding means to the second holding means. The first machining area and the second machining area are arranged in a vertical direction. A grinding device is provided.

  Preferably, the first holding means includes a chuck table that holds a workpiece, and a first mounting base on which the chuck table is rotatably mounted, and the second holding means includes: The chuck table has a second mounting base on which the chuck table is rotatably mounted, and the transport unit transports the chuck table together with the workpiece from the first holding unit to the second mounting base. .

  Since the grinding device of the present invention has a plurality of processing regions arranged in the vertical direction, the footprint can be reduced in size.

  According to the second aspect of the present invention, the risk of breakage of the wafer after grinding can be reduced by conveying the chuck table holding the wafer together.

It is a side view of the grinding device of a 1st embodiment of the present invention. It is a perspective view of the rough grinding unit part of the grinding device of a 1st embodiment. It is a side view of the grinding device of a 2nd embodiment of the present invention. It is a perspective view explaining conveyance of a chuck table. It is a side view of the grinding device of a 3rd embodiment of the present invention.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. Referring to FIG. 1, a side view of a grinding apparatus 2 according to a first embodiment of the present invention is shown. A first mounting base 8 is fixed to an intermediate portion of the vertical column 6 erected on the floor 4. A first chuck table 10 is rotatably disposed on the first mounting base 8, and the first mounting base 8 and the first chuck table 10 constitute first holding means 9.

  Reference numeral 12 denotes a rough grinding unit, and a spindle 16 is rotatably accommodated in a housing 14. The spindle 16 is rotationally driven by a motor (not shown) housed in the housing 14.

  A wheel mount 18 is fixed to the tip of the spindle 16, and a rough grinding wheel 20 is detachably attached to the wheel mount 18 with a screw (not shown). The rough grinding wheel 20 includes an annular base 22 and a plurality of grinding wheels 24 for rough grinding fixed to the outer periphery of the lower end of the annular base 22.

  A first fixed base 30 is fixed to the vertical column 6, and a pair of guide rails (only one is shown) 32 extending in the vertical direction is attached to the first fixed base 30. The rough grinding unit 12 is mounted so as to be movable in the vertical direction along the pair of guide rails 32. The rough grinding unit 12 is attached to a moving base 28 in which the housing 14 moves up and down along a pair of guide rails 32 via a support portion 26.

  As best shown in FIG. 2, the rough grinding unit 12 is a rough grinding unit feed composed of a ball screw 34 and a pulse motor 36 that move the rough grinding unit 12 up and down along a pair of guide rails 32. A mechanism 38 is provided. A ball screw 34 is screwed into a nut built in the moving base 28. When the pulse motor 36 is driven, the ball screw 34 rotates and the moving base 28 is moved in the vertical direction.

  The first holding means 9 including the first mounting base 8 and the first chuck table 10, the rough grinding unit 12, and the rough grinding unit feed mechanism 38 are a first processing region 40 that is the upper half of the vertical column 6. It is arranged.

  A second mounting base 42 is fixed to the floor 4, and a second chuck table 44 is rotatably disposed on the second mounting base 42. The second mounting base 42 and the second chuck table 44 constitute a second holding means 43.

  A second fixed base 64 is attached to the lower part of the vertical column. A pair of guide rails (only one is shown) 66 extending in the vertical direction are attached to the second fixed base 64. A finish grinding unit 46 is mounted along the pair of guide rails 66 so as to be movable in the vertical direction.

  The finish grinding unit 46 includes a housing 48, a spindle 50 rotatably accommodated in the housing 48, and a motor (not shown) accommodated in the housing 48 that rotationally drives the spindle 50.

  A wheel mount 52 is fixed to the tip of the spindle 50, and a finish grinding wheel 54 is detachably attached to the wheel mount 52 by screws (not shown). The finish grinding wheel 54 includes a wheel base 56 and a plurality of grinding wheels 58 for finish grinding fixed to the outer periphery of the lower end of the wheel base 56.

  The finish grinding unit 46 is attached to a moving base 62 whose housing 48 moves up and down along a pair of guide rails 66 via a support portion 60. The finish grinding unit 46 includes a finish grinding unit feed mechanism 70 including a ball screw (not shown) that moves the finish grinding unit 46 in the vertical direction along a pair of guide rails 66 and a pulse motor 68.

  A ball screw of the finish grinding unit feed mechanism 70 is screwed into a nut built in the movable base 62. When the pulse motor 68 is driven, the ball screw rotates and the finish grinding unit 46 is moved in the vertical direction.

  The second holding means 43 including the second mounting base 42 and the second chuck table 44, the finish grinding unit 46, and the finish grinding unit feed mechanism 70 are the second machining area 70 which is the lower half of the vertical column 6. It is arranged.

  A pair of guide rails (only one is shown) 74 is erected on the floor 4 so as to face the vertical column 6. A ball screw (not shown) extending in the vertical direction is disposed between the pair of guide rails 74, and a pulse motor 76 is connected to one end of the ball screw. The ball screw is screwed into a nut built in a moving member 78 that moves in the vertical direction.

  A transfer robot 80 having a hand 82 movable in the horizontal direction is attached to the moving member 78. A transfer robot moving mechanism 77 for moving the transfer robot 80 in the vertical direction is constituted by a ball screw and a pulse motor 76 (not shown).

  Hereinafter, the operation of the grinding apparatus 2 of the present embodiment will be described. As shown in FIG. 1, a semiconductor wafer (hereinafter sometimes simply referred to as a wafer) W is sucked and held on the first chuck table 10. A protective tape is attached to the front surface of the wafer W, the protective tape side is sucked and held by the first chuck table 10, and the back surface is exposed.

  From the state shown in FIG. 1, while rotating the first chuck table 10 at, for example, 300 rpm, the coarse grinding wheel 20 is rotated in the same direction as the first chuck table 10 at, for example, 6000 rpm, and the coarse grinding unit feed mechanism 38 is The grinding wheel 24 for rough grinding is operated to contact the back surface of the wafer W.

  Then, the rough grinding wheel 20 is ground and fed by a predetermined amount at a predetermined grinding feed speed, and rough grinding of the back surface of the wafer W is performed. This rough grinding is performed while supplying a grinding liquid to the grinding wheel 24 and the wafer W. The wafer W is ground to a desired thickness while measuring the thickness of the wafer W with a contact-type or non-contact-type thickness measurement gauge.

  When the rough grinding is finished, the pulse motor 76 of the transfer robot moving mechanism 77 is driven from the state shown in FIG. 1, and the hand 82 of the transfer robot 80 sucks and holds the wafer W held on the first chuck table 10. Raise it to the highest possible position.

  Next, the hand 82 of the transfer robot 80 is moved in the horizontal right direction and positioned above the wafer W held on the first chuck table 10. After the suction holding of the first chuck table 10 is released, the back side of the wafer W is sucked and held by the hand 82 of the transfer robot 80.

  Next, after the hand 82 holding and holding the wafer W is moved in the horizontal left direction, the pulse motor 76 of the transfer robot drive mechanism 77 is driven, and the hand 82 of the transfer robot 80 puts the wafer W on the second chuck table 44. The transfer robot 80 is lowered to the delivery position.

  Next, the hand 82 that has attracted the wafer W is moved in the horizontal right direction to place the wafer W on the second chuck table 44. After the suction holding of the hand 82 is released, the wafer W is sucked and held by the second chuck table 44. Next, finish grinding of the wafer W is performed by the finish grinding unit 46.

  In this finish grinding, while the second chuck table 44 is rotated at, for example, 300 rpm, the finish grinding wheel 54 is rotated in the same direction as the second chuck table 44, for example, at 6000 rpm, and the finish grinding unit feed mechanism 70 is operated to finish. A grinding wheel 58 for grinding is brought into contact with the back surface of the wafer W.

  Then, the back grinding of the wafer W is performed by feeding the finish grinding wheel 54 downward by a predetermined amount at a predetermined grinding feed speed. This finish grinding is also performed while supplying the grinding liquid to the grinding wheel 58 and the wafer W. The wafer W is finished to a desired thickness, for example, 50 μm, while the thickness of the wafer W is measured by a contact-type or non-contact-type thickness measurement gauge.

  In the grinding device 2 of the present embodiment, since the first machining area 40 and the second machining area 72 are arranged side by side in the vertical direction, the footprint (occupied space) can be reduced. Therefore, even when grinding a φ450 mm large wafer, the grinding device 2 with a small footprint can be used without increasing the size of the device.

  In the grinding apparatus 2 of the present embodiment, the rough grinding unit 12 is disposed upward and the finish grinding unit 46 is disposed downward. However, the rough grinding unit 12 is disposed downward and the finish grinding unit 46 is disposed. May be arranged above.

  Referring to FIG. 3, a side view of a grinding apparatus 2A according to a second embodiment of the present invention is shown. In the description of the present embodiment, substantially the same components as those of the grinding device 2 of the first embodiment described above are denoted by the same reference numerals, and description thereof is omitted to avoid duplication.

  In the grinding apparatus 2 </ b> A of the present embodiment, the rotary shaft 11 is erected on the first mounting base 8, the rotary shaft 44 is erected on the second mounting base 42, and the chuck table 10 is attached to and detached from the rotary shaft 11. This is different from the first embodiment in that the chuck table 10 is detachably mounted on the rotary shaft 44.

  Furthermore, the hand 82A of the transfer robot 80A of the present embodiment differs from the hand 82 of the transfer robot 80 of the first embodiment in the following points. The hand 82 of the first embodiment is configured to be sucked and held from the upper side of the wafer W, but the hand 82A of the second embodiment has a structure as shown in FIG.

  As shown in FIG. 4, the chuck table 10 includes a frame body 13 formed of a metal such as SUS and a suction holding unit 15 formed of porous ceramics or the like surrounded by the frame body 13. The hand 82 </ b> A is formed in a U shape having a notch 83.

  The grinding apparatus 2A of the present embodiment is configured to reduce the risk of damage to the wafer W thinned by grinding by transporting the wafer W together with the chuck table 10. Hereinafter, the case where the chuck table 10 mounted on the rotating shaft 11 of the first mounting base 8 is mounted on the rotating shaft 45 disposed on the second mounting base 42 will be described.

  When the rough grinding of the wafer W is finished, the pulse motor 76 of the transfer robot moving mechanism 77 is driven from the state shown in FIG. 3 to raise the transfer robot 80A to a predetermined position. Next, the hand 82 </ b> A of the transfer robot 80 </ b> A is moved horizontally to the right and the U-shaped hand 82 </ b> A is inserted below the chuck table 10.

  After the engagement relationship of the chuck table 10 with the rotating shaft 11 is released, the chuck table 10 is lifted by the hand 82A of the transfer robot 80A, and the hand 82A is moved in the horizontal left direction.

  Next, the pulse motor 76 of the transfer robot moving mechanism 77 is driven to lower the transfer robot 80A to a predetermined position. Then, the hand 82 </ b> A supporting the chuck table 10 is moved in the horizontal right direction to mount the chuck table 10 on the rotary shaft 45 disposed on the second mounting base 42. Thus, the preparation for the finish grinding of the wafer W is completed, and the finish grinding of the wafer W is performed by the finish grinding unit 46.

  As described above, in the grinding apparatus 2A of the present embodiment, the wafer W is transported together with the chuck table 10 by the transport robot 80A, so that the risk of breakage of the wafer W after grinding can be reduced.

  Referring to FIG. 5, a side view of a grinding apparatus 2B according to a third embodiment of the present invention is shown. In the description of the present embodiment, substantially the same components as those of the grinding device 2 of the first embodiment shown in FIG. 1 are denoted by the same reference numerals, and the description thereof is omitted to avoid duplication.

  The grinding device 2B of this embodiment is obtained by adding a third processing region 112 for performing polishing to the grinding device 2 of the first embodiment having the first processing region 40 and the second processing region 72.

  In the third processing region 112, a third holding means 85 including a third mounting base 84 and a third chuck table 86, and a polishing unit 88 are disposed. The polishing unit 88 includes a spindle 92 rotatably accommodated in the housing 90, a motor accommodated in the housing 90 that rotationally drives the spindle 22, a wheel mount 94 fixed to the tip of the spindle 92, And a grinding wheel 96 detachably attached to the wheel mount 94 with screws (not shown).

  The polishing wheel 96 includes a base 98 attached to the wheel mount 94 and a polishing pad 98 attached to the base 98. As the polishing pad 98, for example, a fixed abrasive polishing pad in which abrasive grains are dispersed in urethane foam and fixed with an appropriate bond material can be suitably used.

  As the abrasive grains, for example, GC (Green Carbide) abrasive grains having a particle diameter of 0.2 to 1.5 μm are contained in the urethane foam. Instead of foamed urethane, GC abrasive grains may be contained in the nonwoven fabric.

  A third fixed base 104 is attached to a lower portion of the vertical column 6A, and a pair of guide rails (only one is shown) 106 is attached to the third fixed base 104. The polishing unit 88 is attached to a moving base 102 whose housing 90 moves up and down along the pair of guide rails 106 via the support portion 100.

  The polishing unit 88 includes a polishing unit feed mechanism 110 that includes a ball screw (not shown) that moves the polishing unit 88 in the vertical direction along the pair of guide rails 106 and a pulse motor 108.

  A ball screw of the polishing unit feed mechanism 110 is screwed into a nut built in the moving base 102. When the pulse motor 108 of the polishing unit 110 is driven, the ball screw rotates and the polishing unit 88 is moved in the vertical direction.

  Hereinafter, the operation of the grinding apparatus 2B of the present embodiment will be described. Since the rough grinding process and the finish grinding process for the wafer W are the same as those in the first embodiment, the description thereof is omitted. The wafer W that has undergone finish grinding is sucked and held by the hand 82 of the transfer robot 80 and moved to the third processing region 112, and is transferred onto the third chuck table 86 by the hand 82 of the transfer robot 80 and is transferred to the third chuck table 86. The table 86 is sucked and held.

  In the polishing process of the wafer W, while supplying the polishing liquid to the back surface of the wafer W and the polishing pad 98, the third chuck table 86 is rotated and the polishing pad 98 is rotated in the same direction as the third chuck table 86. The polishing pad 98 is pressed against the back surface of the wafer W to polish the back surface of the wafer W.

  By this polishing process, the grinding distortion generated by the finish grinding process is removed. As the polishing liquid, in the present embodiment in which the wafer W is made of silicon, for example, an alkaline polishing liquid is used.

  In the grinding apparatus 2B of the present embodiment, the first machining area 40, the second machining area 72, and the third machining area 112 are arranged side by side in the vertical direction, so that the footprint can be downsized. Furthermore, since the grinding apparatus 2B includes the polishing unit 88, stress relief for removing grinding distortion generated by grinding can be performed.

  In the embodiment shown in FIG. 5, the first machining area 40, the second machining area 72, and the third machining area 112 are arranged in this order from the top. The area 40 may be arranged, the second machining area 72 may be arranged thereon, and the third machining area 112 may be arranged on the top.

2, 2A, 2B Grinding device 6 Vertical column 9 First holding means 10 First chuck table 12 Rough grinding unit 20 Rough grinding wheel 40 First machining area 44 Second chuck table 43 Second holding means 46 Finish grinding unit 54 Finish grinding Wheel 72 Second processing region 74 Guide rail 80 Transfer robot 82, 82A Hand 85 Third holding means 86 Third chuck table 88 Polishing unit 98 Polishing pad 112 Third processing region

Claims (2)

A grinding device for grinding a workpiece,
First holding means for rotatably holding the workpiece;
A first spindle that is rotationally driven, and a first grinding wheel that includes a first grinding wheel that is mounted on the tip of the first spindle and that faces the workpiece held by the first holding means. Grinding means;
A first moving region comprising: first moving means for moving the first grinding means in a direction approaching and separating from the first holding means;
Second holding means for rotatably holding the workpiece;
A second spindle having a second grinding wheel that includes a second grinding wheel that is rotated and driven, and a second grinding wheel that is mounted on the tip of the second spindle and that is held by the second holding means and faces the workpiece. Grinding means;
A second working area comprising: a second moving means for moving the second grinding means in a direction approaching and separating from the second holding means;
Conveying means for conveying a workpiece from the first holding means to the second holding means,
The grinding apparatus, wherein the first machining area and the second machining area are arranged side by side in the vertical direction. The first holding means is
A chuck table for holding the workpiece;
A first mounting base on which the chuck table is rotatably mounted;
The second holding means is
A second mounting base on which the chuck table is rotatably mounted;
The grinding apparatus according to claim 1, wherein the conveying unit conveys the chuck table together with the workpiece from the first holding unit to the second mounting base.

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