JP2010010267A - Working device for semiconductor wafer - Google Patents

Abstract

Provided is a processing apparatus such as a grinding apparatus capable of positioning a semiconductor wafer in a predetermined direction and then carrying it out to the next process.
A semiconductor wafer processing apparatus having a spinner cleaning apparatus 64 for cleaning and spin-drying a ground or polished semiconductor wafer, and having a mark indicating a crystal orientation on the outer periphery, the spinner cleaning apparatus including a spinner cleaning apparatus. Illuminating means for detecting a mark indicating the crystal orientation of the semiconductor wafer by imaging the outer periphery of the table 68, an encoder for detecting the rotation angle of the spinner table, a cleaning water supply nozzle, and a cleaned and spin-dried semiconductor wafer And the control means rotates the spinner table on the basis of the detected mark to position the semiconductor wafer in a predetermined direction, and then the unloading means 66 moves the semiconductor wafer positioned in the predetermined direction. Take it out.
[Selection] Figure 3

Description

  The present invention relates to a semiconductor wafer processing apparatus for grinding or polishing a semiconductor wafer having a crystal orientation mark on its outer periphery and then carrying it out to the next process.

  A semiconductor wafer in which devices such as IC and LSI are formed on the surface, and each device is defined by lines to be divided is ground or polished by a grinding / polishing device and processed to a desired thickness, and then a dicing device or the like The line to be divided is cut and divided into individual devices, and the divided devices are widely used in electric devices such as mobile phones and personal computers.

  In recent years, in order to achieve weight reduction and miniaturization of electrical equipment, it has been required to grind these workpieces such as semiconductor wafers to a very thin thickness of, for example, 100 μm or less and further 50 μm or less.

  However, there is a problem that a semiconductor wafer ground to be very thin, for example, 50 μm or less, is easily damaged and is difficult to handle. Usually, a semiconductor wafer whose back surface is ground or polished is taken out from a grinding / polishing apparatus and then attached to a dicing tape mounted on an annular frame before dicing to facilitate chip pick-up after dicing. The

  On the other hand, when cutting a semiconductor wafer with a dicing machine, it is necessary to align the direction of the wafer when sticking to a dicing tape so that the machine can automatically detect the cutting position.

Therefore, in general, the ground or polished wafer is transported to a tape sticking device, and then placed on a positioning table of the tape sticking device and aligned in a predetermined direction, and then transferred to a tape mounting table. And the dicing tape is attached.
JP 2006-21264 A

  However, since the bending strength of a thin semiconductor wafer is not sufficient, it is often damaged when it is placed on a table, and the possibility of breakage increases as the number of times of placement on the table increases.

  The present invention has been made in view of these points, and an object of the present invention is to process a semiconductor wafer that can be taken out to the next process after the ground or polished semiconductor wafer is aligned in a predetermined direction. Is to provide a device.

  According to the present invention, a chuck table for holding a semiconductor wafer having a crystal orientation mark on the outer periphery, a processing means for grinding or polishing the back surface of the semiconductor wafer held on the chuck table to a desired thickness, A spinner cleaning apparatus for cleaning and spin drying the polished semiconductor wafer, a control means for controlling the spinner cleaning apparatus, and an unloading means for transporting the cleaned and spin dried semiconductor wafer from the spinner cleaning apparatus to the next process. A semiconductor wafer processing apparatus provided, wherein the spinner cleaning apparatus detects a rotation angle of the spinner table having a diameter substantially equal to or larger than that of the semiconductor wafer and rotating while holding the semiconductor wafer. An encoder, a cleaning water supply nozzle for supplying cleaning water to the semiconductor wafer, and a spinner table An image pickup means including an illuminating means for detecting the mark indicating the crystal orientation of the semiconductor wafer by imaging the outer periphery of the cleaned and spin-dried semiconductor wafer disposed above the wafer holding surface; Based on the mark, the control means rotates the spinner table to position the semiconductor wafer in a predetermined direction, and then the unloading means carries out the semiconductor wafer positioned in the predetermined direction. A wafer processing apparatus is provided.

  According to a second aspect of the present invention, in the first aspect of the invention, the spinner table includes a porous adsorbing portion that adsorbs and holds the semiconductor wafer and a base having an outer peripheral portion that surrounds the porous adsorbing portion. Has an irregular reflection surface for irregularly reflecting light from the illumination means when imaged by the imaging means.

  According to the first aspect of the present invention, since the semiconductor wafer can be aligned in a predetermined direction on the spinner table, the direction of the semiconductor wafer is aligned again in the next process such as a tape mounting process for attaching a dicing tape. Steps can be omitted and damage to the semiconductor wafer can be reduced.

  According to the second aspect of the invention, since the outer periphery of the spinner table has the irregular reflection surface for irregularly reflecting the light from the imaging means, the outer periphery of the semiconductor wafer can be clearly detected when the semiconductor wafer is imaged.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. FIG. 1 is a perspective view of a semiconductor wafer 11 before being processed to a predetermined thickness. The semiconductor wafer 11 shown in FIG. 1 is made of, for example, a silicon wafer having a thickness of 700 μm, and a plurality of streets 13 are formed in a lattice shape on the surface 11a, and a plurality of streets partitioned by the plurality of streets 13 are formed. A device 15 such as an IC or LSI is formed in the region.

  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 region 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. The direction of the notch 21 is parallel to the street 13.

  A protective tape 23 is attached to the surface 11a of the semiconductor wafer 11 by a protective tape attaching process. Therefore, when the semiconductor wafer 11 is ground, 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, a grinding apparatus 2 for grinding the back surface 11b of the semiconductor wafer 11 thus formed to a predetermined thickness will be described with reference to FIG. Reference numeral 4 denotes a housing of the grinding apparatus 2, and two columns 6 a 6 b are erected vertically at the rear of the housing 4.

  A pair of guide rails (only one is shown) 8 extending in the vertical direction is fixed to the column 6a. A rough grinding unit 10 is mounted along the pair of guide rails 8 so as to be movable in the vertical direction. The rough grinding unit 10 is attached to a moving base 12 whose housing 20 moves up and down along a pair of guide rails 8.

  The rough grinding unit 10 includes a housing 20, a spindle (not shown) rotatably accommodated in the housing 20, a servo motor 22 that rotationally drives the spindle, and a plurality of rough grinding grinding wheels fixed to the tip of the spindle. A grinding wheel 24 having 26 is included.

  The rough grinding unit 10 includes a rough grinding unit moving mechanism 18 including a ball screw 14 and a pulse motor 16 that move the rough grinding unit 10 up and down along a pair of guide rails 8. When the pulse motor 16 is pulse-driven, the ball screw 14 rotates and the moving base 12 is moved in the vertical direction.

  A pair of guide rails 19 (only one is shown) 19 extending in the vertical direction are also fixed to the other column 6b. A finish grinding unit 28 is mounted along the pair of guide rails 19 so as to be movable in the vertical direction.

  The finish grinding unit 28 is attached to a moving base (not shown) in which the housing 36 moves in the vertical direction along the pair of guide rails 19. The finish grinding unit 28 includes a housing 36, a spindle (not shown) rotatably accommodated in the housing 36, a servo motor 38 that rotationally drives the spindle, and a grinding wheel 42 for finish grinding fixed to the tip of the spindle. A grinding wheel 40 is included.

  The finish grinding unit 28 includes a finish grinding unit moving mechanism 34 including a ball screw 30 and a pulse motor 32 that move the finish grinding unit 28 in the vertical direction along the pair of guide rails 19. When the pulse motor 32 is driven, the ball screw 30 rotates and the finish grinding unit 28 is moved in the vertical direction.

  The grinding device 2 includes a turntable 44 disposed so as to be substantially flush with the upper surface of the housing 4 on the front side of the columns 6a and 6b. The turntable 44 is formed in a relatively large-diameter disk shape, and is rotated in a direction indicated by an arrow 45 by a rotation drive mechanism (not shown).

  On the turntable 44, three chuck tables 46 are arranged so as to be rotatable in a horizontal plane, spaced from each other by 120 ° in the circumferential direction. The chuck table 46 has a suction chuck formed in a disk shape by a porous ceramic material, and sucks and holds the wafer placed on the holding surface of the suction chuck by operating a vacuum suction means.

  The three chuck tables 46 arranged on the turntable 44 are rotated in accordance with the turntable 44, so that the wafer loading / unloading area A, rough grinding area B, finish grinding area C, and wafer loading / unloading are performed. The region A is sequentially moved.

  In the front portion of the housing 4, a wafer cassette 50, a wafer transfer robot 54 having a link 51 and a hand 52, a positioning table 56 having a plurality of positioning pins 58, a wafer carry-in mechanism (loading arm) 60, and a wafer carry-out A mechanism (unloading arm) 62, a spinner cleaning device 64 that cleans and spin-drys the ground wafer, and an unloading means 66 that transports the ground wafer cleaned and spin-dried by the spinner cleaning device 64 to the next process. It is arranged.

  The spinner cleaning device 64 has a spinner table 68 that rotates while sucking and holding the ground semiconductor wafer. The spinner table 68 has a diameter that is approximately equal to or larger than the diameter of the semiconductor wafer.

  As shown in FIG. 4, the spinner table 68 includes a porous suction portion 70 that sucks and holds the wafer 11 and a base 71 having an outer peripheral portion 72 that surrounds the porous suction portion 70. The base 71 having the outer peripheral portion 72 is made of, for example, white ceramic, and the upper surface 72a is formed as an irregular reflection surface.

  As an alternative, the outer peripheral portion 72 can be formed of a metal such as SUS. In this case, the upper surface 72a is subjected to rough grinding to be a irregular reflection surface. The outer peripheral part 72 can also be formed, for example from the resin colored brightly, and the upper surface 72a is also used as the irregular reflection surface.

  Or you may make it form the outer peripheral part 72 from the combination of a metal, a ceramic, and resin. The upper surface (wafer holding surface) of the porous suction portion 70 and the upper surface 72a of the outer peripheral portion 72 are formed flush with each other.

  The spinner cleaning device 64 has a cleaning water supply nozzle (not shown) that supplies cleaning water toward the ground wafer that is adsorbed and held on the spinner table 68. An image pickup means 76 for picking up and detecting the mark 21 indicating the crystal orientation of the semiconductor wafer 11 is attached downward to the cover 74 of the spinner cleaning device 64.

  As shown in FIG. 4, an illuminating unit 78 that illuminates the outer peripheral portion of the wafer 11 and the upper surface 72 a of the outer peripheral portion 72 of the spinner table 68 is attached to the imaging unit 76. The image pickup means 76 is attached to the cover 74 so as to be able to image the outer peripheral portion of the semiconductor wafer 11 and the upper surface 72a of the outer peripheral portion 72 of the spinner table 68. The spinner cleaning device 64 has an encoder that detects the rotation angle of the spinner table 68.

  When the wafer after finish grinding is positioned in the wafer loading / unloading area A by rotating the turntable 44, the suction pad 62b of the wafer unloading mechanism (unloading arm) 62 sucks the wafer, and the unloading arm 62 , The wafer is transported to the spinner table 68 of the spinner cleaning device 64 and sucked and held by the spinner table 68.

  The wafer held by the spinner table 68 is cleaned while rotating the spinner table 68 at about 800 rpm while supplying the cleaning water from the cleaning water supply nozzle, and after the cleaning, the supply of the cleaning water from the cleaning water supply nozzle is stopped. The spinner table 68 is rotated at a high speed such as about 3000 rpm to spin dry the washed wafer.

  The outer peripheral edge portion of the cleaned and spin-dried wafer 11 is imaged by the imaging means 76 while irradiating illumination light 80 from the illumination means 78 to the outer peripheral edge portion of the wafer 11 and the upper surface 72 a of the outer peripheral portion 72 of the spinner table 68. .

  Since the back surface of the wafer 11 is mirror-finished, the illumination light 80 is specularly reflected at the outer peripheral edge portion of the wafer 11 as indicated by reference numeral 82. On the other hand, since the upper surface 72 a of the outer peripheral portion 72 of the spinner table 68 is subjected to irregular reflection processing, the illumination light 80 is irregularly reflected by the upper surface 72 a of the outer peripheral portion 72 of the spinner table 68 as indicated by reference numeral 84.

  As a result, the outer peripheral edge portion of the wafer 11 is imaged whitish, and the upper surface 72a of the outer peripheral portion 72 of the spinner table 68 is imaged blackish due to irregular reflection, so that the outer peripheral edge portion of the wafer 11 can be detected clearly.

  By continuously imaging with the imaging means 76 while rotating the spinner table 68, the notch 21 indicating the crystal orientation formed on the outer periphery of the wafer 11 can be easily detected.

  Based on the detected notch 21, the controller of the grinding apparatus 2 rotates the spinner table 68 by a predetermined amount to position the semiconductor wafer 11 in a predetermined direction, and then the unloading means 66 sucks the wafer positioned in the predetermined direction. Then, for example, it conveys to the tape mount table of a tape sticking apparatus.

  In this tape applicator, the direction of the notch 21 of the wafer 11 is approximately perpendicular to the straight portion 86 of the annular frame F having notches 88 and 90 on both sides of the dicing tape T having the outer peripheral portion attached to the annular frame F. Then, the semiconductor wafer 11 is stuck.

  In the present embodiment, the spinner cleaning device 64 includes the imaging unit 76, and the semiconductor wafer is positioned in a predetermined direction by the spinner table 68 based on the notch 21 of the wafer 11 detected by imaging by the imaging unit 76. Therefore, it is possible to omit the alignment table that has been necessary in the conventional tape applicator. Therefore, it is possible to omit the step of aligning the direction of the wafer again in the next process such as a tape sticking process, and the damage of the semiconductor wafer can be reduced.

  The grinding device 2 of the above-described embodiment includes the rough grinding unit 10 and the finish grinding unit 28. However, instead of the finish grinding unit 28, a grinding unit with a polishing buff attached to the tip is provided. For example, the back surface of the ground wafer can be polished to a mirror surface.

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 an embodiment of the present invention. It is a schematic diagram which shows the state at the time of imaging of the outer periphery edge part of a semiconductor wafer. It is a perspective view of the semiconductor wafer of the state with which the annular frame was mounted | worn.

Explanation of symbols

2 Grinding device 10 Rough grinding unit 11 Semiconductor wafer 13 Street 15 Device 21 Notch 28 Finish grinding unit 44 Turntable 46 Chuck table 60 Wafer loading mechanism (loading arm)
62 Wafer unloading mechanism (unloading arm)
64 Spinner cleaning device 66 Unloading means 68 Spinner table 76 Imaging means 78 Illumination means

Claims (3)

A chuck table for holding a semiconductor wafer having a crystal orientation mark on its outer periphery, a processing means for grinding or polishing the back surface of the semiconductor wafer held on the chuck table to a desired thickness, and a ground or polished semiconductor wafer A semiconductor wafer comprising: a spinner cleaning apparatus that cleans and spin-drys the semiconductor wafer; a control unit that controls the spinner cleaning apparatus; and a carry-out means that transports the cleaned and spin-dried semiconductor wafer from the spinner cleaning apparatus to the next process. A processing device,
The spinner cleaning apparatus includes a spinner table having a diameter substantially equal to or larger than that of a semiconductor wafer and rotating while holding the semiconductor wafer;
An encoder for detecting the rotation angle of the spinner table;
A cleaning water supply nozzle for supplying cleaning water to the semiconductor wafer;
Imaging means including an illuminating means that is disposed above the wafer holding surface of the spinner table and images the outer periphery of the cleaned and spin-dried semiconductor wafer to detect the mark indicating the crystal orientation of the semiconductor wafer. And
The control means rotates the spinner table based on the detected mark to position the semiconductor wafer in a predetermined direction, and then the carry-out means carries out the semiconductor wafer positioned in the predetermined direction. Semiconductor wafer processing equipment. The spinner table has a porous adsorption part for adsorbing and holding a semiconductor wafer;
A base having an outer peripheral portion surrounding the porous adsorption portion;
2. The semiconductor wafer processing apparatus according to claim 1, wherein the outer peripheral portion has an irregular reflection surface for irregularly reflecting light from the illuminating means when imaged by the imaging means.   3. The semiconductor wafer processing apparatus according to claim 2, wherein the outer peripheral portion is made of a material selected from the group consisting of metal, ceramic and resin, and a combination thereof.

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