JP2009302369A - Method and apparatus for processing plate-like object - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a processing apparatus capable of grinding and polishing a large-sized wafer without requiring any large-scaled system. <P>SOLUTION: The present invention relates to a processing apparatus for grinding or polishing a rear side of a plate-like object after dividing the plate-like object including: a dividing chuck table for holding the plate-like object; an imaging means for detecting a grinding area of the plate-like object; a grinding means for dividing the plate-like object held on the dividing chuck table to form four or more divided pieces; a grinding-polishing chuck table which has adsorption areas corresponding to shapes of the divided pieces and adsorbs and holds the divided pieces; a feeding means for feeding the divided pieces from the dividing chuck table to the grinding-polishing chuck table; and a processing means which is disposed in counter to the grinding-polishing chuck table for grinding or polishing the divided pieces adsorbed and held on the grinding-polishing chuck table. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a method and an apparatus for grinding or polishing a plate-like object such as a semiconductor wafer, and more particularly to a method and an apparatus for grinding or polishing a plate-like object having a large diameter of 450 mm or the like.

  IC, LSI, and other devices are divided by the planned division lines, and multiple wafers are formed on the surface, and various substrates such as resin substrates, various ceramic substrates and glass substrates used for electronic parts are ground on the back. After being polished and formed to a predetermined thickness, it is divided into individual devices by a dicing apparatus or a laser processing apparatus, and each divided device is used in various electronic apparatuses.

  In recent years, these plate-like objects have been increased in size in order to increase the amount of chips taken per work, and in particular, standardization of φ450 mm has been promoted for semiconductor wafers. On the other hand, as a device for grinding and polishing the back surface of these plate-like objects, a grinding and polishing device called a grinder provided with rough grinding means and finish grinding (polishing) means is widely used.

In these grinding / polishing apparatuses, a plurality of chuck tables for holding a work piece are provided on the turn table at equal intervals in the circumferential direction, and the work piece is held on the chuck table. As a result of the rotation, a series of processes from rough grinding to finish grinding or polishing are sequentially performed by a grinding means or a polishing means arranged opposite to the turntable.
JP 2001-284303 A

  Therefore, when the semiconductor wafer is shifted from φ200 mm, which is currently widely used, to φ450 mm, for example, the grinding / polishing apparatus becomes very large and requires very high rigidity. In addition, the diameter of the turntable on which a plurality of chuck tables are mounted becomes very large, and a large amount of energy is required for the rotation mechanism and the like.

  The present invention has been made in view of the above points, and the object of the present invention is to provide a method for processing a plate-like material that can grind and polish a large-sized plate-like material without requiring a large-sized device. And providing a processing apparatus.

  According to invention of Claim 1, it is a processing method of a plate-shaped object, Comprising: The plate-shaped object division | segmentation process which divides | segments a plate-shaped object into four or more pieces with a cutting means, Chuck the surface side of the divided | segmented plate-shaped object And a plate-like material processing step of grinding or polishing the back surface of the plate-like material while being sucked and held by a table.

  According to a fourth aspect of the present invention, there is provided a processing apparatus for grinding or polishing a back surface of a plate-like object after the plate-like object is divided, the dividing chuck table for holding the plate-like object, and the plate-like object. An imaging means for detecting a cutting area, a cutting means for dividing a plate-like object held on the dividing chuck table to form four or more divided pieces, and an adsorption area corresponding to the shape of the divided pieces are provided. A grinding / polishing chuck table that holds the divided pieces by suction, conveying means for conveying the divided pieces from the dividing chuck table to the grinding / polishing chuck table, and the grinding / polishing chuck table. There is provided a processing device provided with processing means arranged to face and grind or polish the back surface of the divided piece adsorbed and held by the grinding / polishing chuck table.

  Preferably, the imaging means comprises an infrared (IR) camera. Preferably, the cutting means includes a cutting blade and a rotating spindle on which the cutting blade is mounted. As an alternative, the cutting means includes a laser beam irradiation means for irradiating a laser beam.

  According to the first aspect of the invention, in order to perform grinding and polishing after the plate is divided into four or more pieces in advance, a large plate is ground and polished using an existing grinding and polishing apparatus. be able to.

  According to the invention described in claim 4, since the processing apparatus for performing grinding / polishing includes the cutting means, the plate-like object can be divided into small pieces before grinding / polishing, and the large-sized dividing chuck table and the cutting means can be divided. It is possible to provide a processing apparatus that performs grinding and polishing on a large plate-shaped object without increasing the size of the entire apparatus simply by being provided.

  Therefore, less energy is used than a large-sized device, and the environmental load can be reduced. Moreover, since a large turntable and a large grinding / polishing means are not required, the grinding / polishing accuracy can be kept high.

  Hereinafter, the processing method and processing apparatus of the plate-shaped object of the present invention are explained in detail with reference to drawings. FIG. 1 is a perspective view of a semiconductor wafer before being processed to a predetermined thickness. A semiconductor wafer 11 shown in FIG. 1 has a diameter of φ450 mm, and is made of, for example, a silicon wafer having a thickness of 700 μm. A plurality of streets 13 are formed in a lattice shape on a surface 11a. Devices 15 such as ICs and LSIs are formed in a plurality of regions partitioned by 13.

  The semiconductor wafer 11 configured as described above includes a device region 17 in which the device 15 is formed, and an outer peripheral surplus region 19 that surrounds the device 17. A notch 21 is formed on the outer periphery of the semiconductor wafer 11 as a mark indicating the crystal orientation of the silicon wafer.

  A protective tape 23 is attached to the surface 11a of the semiconductor wafer 11 by a protective tape attaching process. Therefore, the front surface 11a of the semiconductor wafer 11 is protected by the protective tape 23, and the back surface 11b is exposed as shown in FIG.

  Hereinafter, the grinding apparatus 2 according to the first embodiment for grinding the back surface 11b of the large-diameter semiconductor wafer 11 thus formed to a predetermined thickness will be described with reference to FIG. The grinding device 2 has a housing 4, and a cutting device 6 is mounted on the side surface of the housing 4.

  That is, the cutting device 6 is mounted on the grinding device 2 by fixing the housing 8 of the cutting device 6 to the housing 4 of the grinding device 2. A pair of guide rails 10 extending in the Y-axis direction are fixed to the surface of the housing 8 of the cutting device 6.

  A Y-axis moving block 12 is mounted along these guide rails 10 so as to be movable in the Y-axis direction. That is, the Y-axis moving block 12 is moved in the Y-axis direction by the Y-axis moving mechanism 18 constituted by the ball screw 14 and the pulse motor 16.

  A pair of guide rails 20 extending in the X-axis direction are fixed on the Y-axis moving block 12. An L-shaped X-axis moving block 22 is mounted so as to be movable in the X-axis direction along these guide rails 20. That is, the X-axis moving block 22 is moved in the X-axis direction by an X-axis moving mechanism 28 including a ball screw 24 and a pulse motor 26.

  A pair of guide rails 30 extending in the Z-axis direction are fixed to the surface of the X-axis moving block 22, and a cutting means (cutting unit) 32 is provided so as to be movable in the Z-axis direction along these guide rails 30. It is mounted on the X-axis moving block 22. That is, the cutting unit 32 is moved in the Z-axis direction with respect to the X-axis moving block 22 by the Z-axis moving mechanism 38 constituted by the ball screw 34 and the pulse motor 36.

  A spindle 42 is rotatably accommodated in the spindle housing 40 of the cutting unit 32, a servo motor (not shown) is connected to one end (base end) of the spindle 42, and a cutting blade 44 is attached to the tip thereof. Yes. Further, the spindle housing 40 is mounted with an imaging means 46 having an infrared (IR) camera.

  Two columns 48 and 66 are erected vertically at the rear of the housing 4. A pair of guide rails (only one is shown) 50 extending in the vertical direction is fixed to the column 48. A rough grinding means (rough grinding unit) 52 is mounted along the pair of guide rails 50 so as to be movable in the vertical direction. The rough grinding unit 52 is attached to a moving base (not shown) in which the housing 60 moves in the vertical direction along the pair of guide rails 50.

  The rough grinding unit 52 includes a housing 60, a spindle (not shown) rotatably accommodated in the housing 60, a servo boat 62 that rotationally drives the spindle, and a plurality of rough grinding grinding wheels fixed to the tip of the spindle. A grinding wheel 64 is included.

  The rough grinding unit 52 includes a rough grinding unit moving mechanism 58 including a ball screw 54 that moves the rough grinding unit 52 in the vertical direction along a pair of guide rails 50 and a pulse motor 56. When the pulse motor 56 is driven, the ball screw 54 rotates and the rough grinding unit 52 is moved in the vertical direction.

  Also fixed to the other column 66 is a pair of guide rails 68 (only one shown) extending in the vertical direction. A finishing grinding means (finishing grinding unit) 70 is mounted along the pair of guide rails 68 so as to be movable in the vertical direction.

  The finish grinding unit 70 is attached to a moving base 71 whose housing 78 moves up and down along a pair of guide rails 68. The finish grinding unit 70 includes a housing 78, a spindle (not shown) rotatably accommodated in the housing 78, a servo boat 80 that rotationally drives the spindle, and a grinding wheel having a grinding wheel for finish grinding fixed to the tip of the spindle. A wheel 82 is included.

  The finish grinding unit 70 includes a finish grinding unit moving mechanism 76 including a ball screw 72 that moves in the vertical direction along a pair of guide rails 68 and a pulse motor 74. When the pulse motor 74 is driven, the ball screw 72 rotates and the finish grinding unit 70 is moved in the vertical direction.

  The grinding device 2 includes a turntable 84 disposed so as to be substantially flush with the upper surface of the housing 4 on the front side of the columns 48 and 66. The turntable 84 is formed in a relatively large-diameter disk shape, and is rotated clockwise by a rotation driving mechanism (not shown).

  On the turntable 84, three chuck tables 86a, 86b, 86c are arranged so as to be rotatable in a horizontal plane, spaced from each other by 120 degrees in the circumferential direction. Each of the chuck tables 86a to 86c has a suction chuck 88 formed in a disk shape by a porous ceramic material, and sucks the wafer placed on the holding surface of the suction chuck 88 by operating a vacuum suction means. Hold. The shape of the suction chuck 88 substantially matches the shape of a four-piece piece of the wafer 11 described later.

  The three chuck tables 86a to 86c arranged on the turntable 84 are sequentially moved to the wafer carry-in / out region, the rough grinding region, and the finish grinding region by appropriately rotating the turntable 84. . In the state shown in the drawing, the chuck table 86a is positioned in the wafer carry-in / out region, the chuck table 86b is positioned in the rough grinding region, and the chuck table 86c is positioned in the finish grinding region.

  The front portion of the housing 4 includes a first wafer cassette 90, a second wafer cassette 92, a wafer transfer robot 94, and a chuck table 96 for chucking and holding the wafer 11 for splitting into four pieces. A wafer carry-in mechanism (loading arm) 98, a wafer carry-out mechanism (unloading arm) 100, and a spinner unit 102 are provided.

  The wafer transfer robot 94 is configured to be movable in the X-axis, Y-axis, and Z-axis directions, and is configured to be rotatable about a vertical axis. The hand 95 of the wafer transfer robot 94 has a vacuum suction pad on its lower surface.

  FIG. 4 shows a schematic plan view of the grinding apparatus 2 described with reference to FIG. The division chuck table 96 has a cross-shaped groove 97 for dividing the wafer 11 having a diameter of 450 mm into four.

  Hereinafter, a method of grinding the back surface of the divided piece by dividing the large-diameter wafer 11 into four parts using the grinding apparatus 2 configured as described above will be described. As shown in FIG. 2, a plurality of wafers 11 are stored in the first wafer cassette 90 with the back surface 11b facing up.

  First, the wafer 95 accommodated in the first wafer cassette 90 is sucked by the hand 95 of the wafer transfer robot 94 and the wafer 11 is placed on the chuck table 96 for division. Then, the image pickup means 46 is moved in the direction of arrow A (X-axis direction) and the dividing chuck table 96 is moved in the direction of arrow B (Y-axis direction), and the region to be cut is picked up by the image pickup means 46 having an IR camera. Take an image.

  Although the wafer 11 is placed on the chuck table 96 for division downward, the imaging means 46 has an IR camera, so the imaging means 46 detects the target pattern, and the target pattern registered in advance is detected. Perform pattern matching. This pattern matching is performed in at least two places along the same street.

  When the patterns match, the division chuck table 96 is rotated by θ to correct the angle, and the X-axis moving mechanism 28 is driven to cut the cutting unit 32 by the distance between the target pattern and the street centerline. Is moved in the X-axis direction to align the center street 13 of the wafer 11 to be cut with the cutting blade 44.

  In a state where the street to be cut and the cutting blade 44 are aligned, the cutting unit 32 is lowered while rotating the cutting blade 44 at a high speed, and the dividing chuck table 96 is moved in the arrow B direction (Y-axis direction). When moved to, the aligned street is cut.

  When the dividing chuck table 96 is rotated 90 degrees, the streets orthogonal to the cut streets are aligned with the cutting blade 44 in the Y-axis direction. Therefore, when the cutting unit 32 is lowered while the cutting blade 44 is rotated at a high speed and the dividing chuck table 96 is moved in the Y-axis direction, the aligned street is cut.

  As a result, the large-diameter wafer 11 is equally divided into four pieces, and fan-shaped divided pieces are obtained. Since the dividing chuck table 16 has a cross-shaped groove 97, even if the cutting blade 44 cuts into the chuck table 96, the chuck table 96 is not damaged.

  The fan-shaped divided pieces thus divided into four pieces are sucked by the loading arm 98 and loaded onto the chuck table 86a positioned in the wafer carry-in / out region, and the wafer divided by operating the suction chuck 88 is operated. Hold the suction.

  Next, the turntable 84 is rotated 120 degrees in the direction of arrow C (clockwise direction) in FIG. 4, and the chuck table 86 a is positioned in the rough grinding region immediately below the rough grinding unit 52. At substantially the same time, the split chuck table 96 is rotated 90 degrees counterclockwise, and the next split piece is sucked by the loading arm 98 and placed on the chuck table 86c positioned in the wafer loading / unloading area. The wafer is sucked and held by the suction chuck 88.

  While rotating the chuck table 86a in the direction of arrow E at, for example, 300 rpm with respect to the wafer adsorbed by the chuck table 86a and positioned in the rough grinding region, the rough grinding wheel 64 is moved in the same direction as the chuck table 86a (direction of arrow D ), For example, at 6000 rpm, and the rough grinding unit moving mechanism 58 is operated to bring the grinding wheel for rough grinding into contact with the back surface of the wafer.

  Then, the rough grinding wheel 64 is ground and fed by a predetermined amount at a predetermined grinding feed speed to perform rough grinding of the wafer. The wafer is finished to a desired thickness while measuring the thickness of the wafer with a contact-type thickness measurement gauge (not shown).

  The chuck table 86a holding the wafer after the rough grinding is positioned in the finish grinding region immediately below the finish grinding unit 70 by rotating the turntable 84 by 120 degrees, and finish grinding having a grinding wheel 82 for finish grinding. Finish grinding by the unit 70 is performed.

  The chuck table 86a holding the wafer after finish grinding is positioned again in the wafer carry-in / out area by rotating the turntable 84 by 120 degrees. After the wafer held by the chuck table 86 a is released from suction, the unloading arm 100 sucks the wafer and turns the unloading arm 100, so that the wafer is conveyed to the spinner unit 102.

  After the wafer is cleaned and spin-dried by the spinner unit 102, it is sucked and held by the wafer transfer robot 94, and is stored in a predetermined position of the second wafer cassette 92.

  In the embodiment shown in FIGS. 3 and 4, the grinding apparatus 2 includes a rough grinding unit 52 and a finish grinding unit 70. Instead of the finish grinding unit 70, a grinding unit in which a polishing buff is attached to the tip. May be provided.

  Alternatively, four chuck tables 86 may be provided on the turntable 84 so as to be 90 degrees apart in the circumferential direction, and a polishing unit may be provided in addition to the rough grinding unit 52 and the finish grinding unit 70.

  In the embodiment described above, the image pickup means 46 is provided with an infrared camera for detecting the target pattern from the back side of the wafer. However, the image pickup means 46 is omitted and a normal CCD camera is used as the wafer transfer robot 94. You may make it mount | wear with the imaging means which has.

  Specifically, the CCD camera is mounted on the wafer transfer robot 94 so that the surface of the wafer attracted by the wafer transfer robot 94 can be imaged. The wafer is picked up by the hand 95 of the wafer transfer robot 94, and the edge of the wafer is picked up by the CCD camera to detect three or more wafer edges.

  For example, assume that three points A, B, and C are detected. The center of the wafer can be detected by obtaining the intersection of the bisector of the line segment AB and the bisector of the line segment BC. After detecting the center of the wafer, the wafer is transferred by the wafer transfer robot 94 and placed on the split chuck table 96 so that the center of the wafer and the center of the split chuck table 96 coincide.

  Next, the wafer is re-adsorbed with the hand 95 so that the center of the wafer and the center of the robot hand 95 are aligned. Next, the wafer is moved onto the CCD camera, the wafer transfer robot 94 is moved in the X-axis direction, and the angle deviation between the X axis of the wafer transfer robot and the street is measured.

  Once the wafer is placed on the dividing chuck table 96, the dividing chuck table 96 is rotated so as to correct the measured angular deviation, and the wafer is sucked and held by the robot hand 95 again. This angle deviation measurement and correction operation is repeated until the wafer street angle deviation is within an allowable range.

  The wafer thus aligned with respect to the robot hand 95 is adjusted by rotating the dividing chuck table 96 so that the street and the cross-shaped groove 97 of the dividing chuck table 96 are aligned, and the wafer is divided. Place on top.

  Referring to FIG. 5, a schematic plan view of a grinding apparatus 2A according to the second embodiment of the present invention is shown. In this embodiment, a laser beam irradiation means 104 is employed instead of the cutting blade 44 that divides the wafer into four parts, and the large-diameter wafer 11 is divided into four parts by the laser beam. As the laser beam emitted from the laser beam irradiation means 104, for example, the third harmonic of a YAG laser having a wavelength of 355 nm is used.

  Since the other components of this embodiment are the same as those of the first embodiment shown in FIGS. 3 and 4, the description thereof is omitted. Note that the cutting device 6 may be configured so that only the Z-axis and the Y-axis are movable without moving in the X-axis direction.

It is a surface side perspective view of a semiconductor wafer. It is a back surface side perspective view of the semiconductor wafer where the protective tape was stuck. 1 is an external perspective view of a grinding apparatus according to a first embodiment of the present invention. FIG. 4 is a schematic plan view of the grinding apparatus shown in FIG. 3. It is a schematic plan view which shows 2nd Embodiment of a grinding device.

Explanation of symbols

2 Grinding device 6 Cutting device 11 Semiconductor wafer 32 Cutting unit 44 Cutting blade 52 Coarse grinding unit 70 Finish grinding unit 84 Turntable 86a to 86c Chuck table 94 Wafer transfer robot 95 Robot hand 96 Dividing chuck table 97 Cross-shaped groove

Claims (7)

A processing method of a plate-like object,
A plate-like material dividing step of dividing the plate-like material into four or more pieces by cutting means;
A plate-like material processing step of grinding or polishing the back surface of the plate-like material while sucking and holding the surface side of the divided plate-like material with a chuck table;
The processing method of the plate-shaped object characterized by comprising.   2. The plate-like material processing method according to claim 1, wherein, in the plate-like material dividing step, the cutting means includes a cutting blade and a rotary spindle on which the cutting blade is mounted.   2. The plate-like material processing method according to claim 1, wherein, in the plate-like material dividing step, the cutting means includes a laser beam irradiation means for irradiating a laser beam. A processing apparatus that grinds or polishes the back surface of the plate-like object after dividing the plate-like object,
A split chuck table for holding a plate-like object;
Imaging means for detecting a cutting region of the plate-like object;
Cutting means for dividing the plate-like object held by the dividing chuck table to form four or more divided pieces;
A chuck table for grinding / polishing having an adsorption region corresponding to the shape of the divided piece, and holding the divided piece by suction;
Conveying means for conveying the divided pieces from the dividing chuck table to the grinding / polishing chuck table;
A processing means arranged to face the grinding / polishing chuck table and grinding or polishing the back surface of the divided piece adsorbed and held by the grinding / polishing chuck table;
A processing apparatus comprising:   The processing apparatus according to claim 4, wherein the imaging unit is an infrared camera.   6. The processing apparatus according to claim 4, wherein the cutting means includes a cutting blade and a rotary spindle on which the cutting blade is mounted.   6. The processing apparatus according to claim 4, wherein the cutting means includes laser beam irradiation means for irradiating a laser beam.

Images