JP2010034249A - Processing apparatus for semiconductor wafer - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a processing apparatus such as a grinding apparatus which positions a semiconductor wafer in a predetermined direction, then carries the semiconductor wafer out to a next process. <P>SOLUTION: The processing apparatus for the semiconductor wafer which grinds or polishes a reverse surface of the semiconductor wafer having a mark indicating crystal orientation at an outer periphery includes a positioning means having a rotatable holding table and detecting the mark of the semiconductor wafer to position the semiconductor wafer in the predetermined direction, and a spinner cleaning device having a spinner table for cleaning or spin-drying the semiconductor wafer having been ground or polished. The cleaning device stops the spinner table at the same position as a position for conveyance to the spinner table after cleaning and spin-drying the wafer, and then carries the wafer out to the next process by a carrying-out means. <P>COPYRIGHT: (C)2010,JPO&INPIT

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 first aspect of the present invention, there is provided a semiconductor wafer processing apparatus for grinding or polishing the back surface of a semiconductor wafer having a crystal orientation mark on its outer periphery, the semiconductor wafer processing apparatus having a rotatable holding table, Positioning means for detecting the mark and positioning the semiconductor wafer in a predetermined direction, a chuck table for rotatably holding the semiconductor wafer positioned in a predetermined direction by the positioning means, and the positioning means to the chuck table A swivelable loading / unloading means for loading a semiconductor wafer and unloading the processed wafer from the chuck table; a processing means for grinding or polishing the back surface of the semiconductor wafer held by the chuck table to a desired thickness; Has a spinner table for cleaning and spin drying ground or polished semiconductor wafers A spinner cleaning means; and a swivelable unloading means for unloading the semiconductor wafer cleaned and spin-dried by the spinner cleaning means from the spinner table to the next process. First fixed point stopping means for stopping rotation, and the spinner cleaning means has second fixed point stopping means for stopping rotation of the spinner table at a fixed position at the end of cleaning and spin drying of the semiconductor wafer, The cleaning means detects the rotation position of the spinner table by the second fixed point stop means, stops the spinner table at the same position as when the semiconductor wafer is loaded into the spinner table after cleaning and spin drying, and The semiconductor wafer is unloaded from the spinner table to the next process by unloading means. Processing apparatus body wafer is provided.

  According to the second aspect of the present invention, the alignment means detects the mark of the semiconductor wafer, but does not position the semiconductor wafer in a predetermined direction. The semiconductor wafer is positioned in a predetermined direction by a cleaning means. That is, the cleaning means positions the mark in the same direction as when the semiconductor wafer is loaded onto the spinner table at the end of cleaning and spin drying of the semiconductor wafer, and then based on the position of the mark on the semiconductor wafer detected by the alignment means. Then, the semiconductor wafer held on the spinner table is positioned in a predetermined direction and is carried out to the next process by the carrying-out means.

  Preferably, the mark indicating the crystal orientation of the semiconductor wafer is formed by a notch or a flat portion formed on the outer periphery of the semiconductor wafer. The alignment means includes a light detector that includes a light emitting portion and a light receiving portion that are disposed above and below the outer peripheral portion of the semiconductor wafer held by the holding table.

  According to the first aspect of the present invention, since the semiconductor wafer can be positioned in a predetermined direction by the alignment means, the direction of the semiconductor wafer is aligned again in the next process such as a tape mounting process for adhering the dicing tape. Steps can be omitted and damage to the semiconductor wafer can be reduced.

  According to the second aspect of the present invention, since the mark of the semiconductor wafer is detected by the alignment means, and the semiconductor wafer can be positioned on the spinner table in a predetermined direction based on the position of the mark, the dicing tape In the next process such as a tape mounting process for attaching the semiconductor wafer, the step of aligning the direction of the semiconductor wafer again can be omitted, and the damage of the semiconductor wafer can be reduced.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. FIG. 1 is a perspective view of the semiconductor wafer 11 of the first embodiment 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. Further, a notch (notch) 21 as a mark indicating the crystal orientation of the silicon wafer is formed on the outer periphery of the semiconductor wafer 11. The direction of the notch 21 is parallel to the street 13 in one direction.

  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.

  Referring to FIG. 3, a perspective view of the semiconductor wafer 11A of the second embodiment before being processed to a predetermined thickness is shown. The semiconductor wafer 11A has an orientation flat part (flat part) 25 instead of the notch 21 of the semiconductor wafer 11 of the first embodiment. The flat portion 25 also functions as a mark indicating the crystal orientation of the silicon wafer 11A. The flat portion 25 is formed in parallel with the street 13 in one direction.

  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.

  Each chuck table 46 has an encoder (not shown) that detects the rotational angle position. Each encoder functions as a fixed point stopping means for stopping the chuck table 46 at a fixed position at the end of grinding or polishing of the semiconductor wafer.

  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.

  A wafer cassette 50, a wafer transfer robot 54 having a link 51 and a hand 52, and an alignment means 56 for aligning the wafer are disposed on the front portion of the housing 4.

  The positioning means 56 includes a rotatable holding table (positioning table) 58, an encoder (not shown) that detects the rotational angle position of the holding table 58, a plurality of positioning pins 59 that are movable in the radial direction, and a photodetector. 72.

  As shown in FIG. 5, the light detector 72 includes a support member 74, and a light emitting unit 76 and a light receiving unit 78 attached to the support member 74 so as to be disposed above and below the outer peripheral portion of the semiconductor wafer. Is included. The light emitting unit 76 is composed of a light emitting element such as a laser diode (LD), and the light receiving unit 78 is composed of a light receiving element such as a photodiode (PD).

  The front portion of the housing 4 further includes a wafer loading mechanism (loading arm) 60, a wafer unloading mechanism (unloading arm) 62, a spinner cleaning device 64 that cleans and spin-drys the ground wafer, and a spinner cleaning device 64. An unloading means 66 for unloading the cleaned and spin-dried wafer to the next process is provided.

  The spinner cleaning device 64 includes a spinner table 68 that rotates by sucking and holding a ground semiconductor wafer, an encoder (not shown) that detects a rotation angle position of the spinner table 68, and a ground wafer that is sucked and held by the spinner table 68. A cleaning water supply nozzle (not shown) for supplying cleaning water toward the head and a cover 70 are provided. The encoder functions as a fixed point stopping means for stopping the spinner table 68 at a fixed position at the end of wafer cleaning and spin drying.

  The grinding operation of the grinding device 2 configured as described above will be described below. The semiconductor wafer accommodated in the wafer cassette 50 is transported by the vertical motion and the forward / backward motion of the wafer transport robot 54 and placed on the holding table 58 of the alignment means 56.

  The wafer placed on the holding table 58 of the positioning means 56 is centered by a plurality of positioning pins 59, and then rotates the holding table 58 so that the light from the light emitting unit 76 passes through the notch 21. By receiving light at 78, the position of the notch 21 is detected.

  After detecting the position of the notch 21 in this way, the holding table 58 is rotated to move the semiconductor wafer 11 in a predetermined direction, that is, when the wafer is carried out to the next process by the carrying-out means 66 after completing a series of grinding processes. Position the semiconductor wafer in a direction that does not need to be aligned.

  The wafer positioned in a predetermined direction on the holding table 58 is placed on the chuck table 46 positioned in the wafer loading / unloading area A by the swinging operation of the loading arm 60 and sucked and held by the chuck table 46. The

  Next, the turntable 44 is rotated 120 degrees, and the chuck table 46 holding the wafer is positioned in the rough grinding region B. For the wafer thus positioned, while rotating the chuck table 46 at, for example, 300 rpm, the grinding wheel 24 is rotated in the same direction as the chuck table 46, for example, at 6000 rpm, and the coarse grinding unit moving mechanism 18 is operated, A grinding wheel 26 for rough grinding is brought into contact with the back surface of the wafer.

  Then, the grinding wheel 24 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 46 holding the wafer after the rough grinding is positioned in the finish grinding region C by rotating the turntable 44 by 120 degrees, and finish grinding by the finish grinding unit 28 having the grinding wheel 42 for finish grinding. Is implemented.

  The chuck table 46 holding the semiconductor wafer after finish grinding is positioned again in the wafer loading / unloading area A by rotating the turntable 44 by 120 degrees.

  After the suction and holding of the wafer held on the chuck table 46 is released, the wafer is adsorbed by the transfer pad 62b of the wafer unloading mechanism (unloading arm) 62, and the unloading arm 62 is rotated to rotate the spinner cleaning device. The wafer is conveyed onto 64 spinner tables 68.

  In the grinding apparatus 2 of this embodiment, when the grinding process in the rough grinding region B and the finish grinding region C is completed, the rotation angle position of the chuck table 46 is detected by the encoder, and the chuck table 46 is located at the same position as when the grinding is started. Stopped at.

  Since the turning angle of the loading arm 60 and the turning angle of the unloading arm 62 are determined in advance, the rough grinding and finish grinding are finished, and the wafer conveyed on the spinner table 68 by the unloading arm 62 has a predetermined orientation. Will be positioned. It should be noted here that the predetermined direction on the spinner table 68 does not necessarily coincide with the predetermined direction in the alignment means 56.

  In the spinner cleaning device 64, the ground semiconductor wafer is cleaned and spin-dried. In the present embodiment, since the rotation angle position of the spinner table 68 is always detected by the encoder, the direction of the wafer after the spin drying is finished coincides with the direction of the wafer carried on the spinner table 68 by the unloading arm 62. To be controlled.

  After the spin drying of the wafer is completed, the carry-out means 66 sucks the wafer positioned in a predetermined direction and conveys it to, for example, a tape mount table of a tape sticking apparatus.

  In this tape applicator, as shown in FIG. 6, an annular frame F having notches 88 and 90 on both sides of a notch 21 of the wafer 11 on a dicing tape T having an outer peripheral portion attached to the annular frame F. The semiconductor wafer 11 is attached so as to be substantially orthogonal to the straight line portion 86 of FIG.

  In the embodiment described above, the alignment unit 56 detects the notch 21 of the semiconductor wafer 11 and positions the semiconductor wafer 11 in a predetermined direction based on the position of the notch 21. Only the position of may be detected.

  In this case, at the end of cleaning and spin drying of the semiconductor wafer 11, the notch 21 is positioned in the same direction as when the semiconductor wafer is loaded onto the spinner table 68, and then the notch of the semiconductor wafer detected by the alignment means 56 is detected. Based on the position 21, the spinner cleaning device 64 positions the semiconductor wafer 11 held on the spinner table 68 in a predetermined direction.

  In each of the embodiments described above, the position of the notch 21 is detected by the alignment means 56 and the semiconductor wafer 11 is positioned in a predetermined direction, or only the notch 21 is detected by the alignment means 56 and the spinner cleaning device 64 is used. Since the semiconductor wafer 11 can be positioned in a predetermined direction, it is possible to omit an alignment table that has been conventionally required for a tape sticking apparatus. 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 having a grinding buff attached at the tip is provided. For example, the back surface of the ground wafer can be polished to a mirror surface.

  In the above-described embodiment, the wafer carry-in mechanism (loading arm) 60 and the wafer carry-out mechanism (unloading arm) 62 are provided. However, the wafer carry-in and carry-out mechanisms are carried out by one wafer carry-in / out mechanism. Anyway.

It is a surface side perspective view of the semiconductor wafer of a 1st embodiment. It is a back surface side perspective view of the semiconductor wafer where the protective tape was stuck. It is a surface side perspective view of the semiconductor wafer of a 2nd embodiment. 1 is an external perspective view of a grinding apparatus according to an embodiment of the present invention. It is a side view which shows the relationship between the semiconductor wafer hold | maintained at the holding table of the alignment means, and a photodetector. 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 56 Positioning means 58 Holding table 60 Wafer loading mechanism (loading arm)
62 Wafer unloading mechanism (unloading arm)
64 Spinner cleaning device 66 Unloading means 68 Spinner table

Claims (5)

A semiconductor wafer processing apparatus for grinding or polishing a back surface of a semiconductor wafer having a crystal orientation mark on its outer periphery,
A positioning means having a rotatable holding table, detecting the mark of the semiconductor wafer and positioning the semiconductor wafer in a predetermined direction;
A chuck table for rotatably holding the semiconductor wafer positioned in a predetermined direction by the alignment means;
Turnable loading / unloading means for loading the semiconductor wafer from the positioning means to the chuck table and unloading the processed wafer from the chuck table;
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 means having a spinner table for cleaning and spin drying a ground or polished semiconductor wafer;
A turnable unloading means for unloading the semiconductor wafer cleaned and spin-dried by the spinner cleaning means from the spinner table to the next process;
The chuck table has first fixed point stop means for stopping rotation at a fixed position at the end of grinding or polishing,
The spinner cleaning means has a second fixed point stop means for stopping the rotation of the spinner table at a fixed position when the semiconductor wafer cleaning and spin drying are completed.
The cleaning means detects the rotation position of the spinner table by the second fixed point stop means, and stops the spinner table at the same position as when the semiconductor wafer is loaded into the spinner table after cleaning and spin drying. An apparatus for processing a semiconductor wafer, wherein the semiconductor wafer is unloaded from the spinner table to the next process by the unloading means. A semiconductor wafer processing apparatus for grinding or polishing a back surface of a semiconductor wafer having a crystal orientation mark on its outer periphery,
Alignment means having a holding table for detecting the mark of the semiconductor wafer and positioning the center of the semiconductor wafer at a predetermined position;
A chuck table for rotatably holding a semiconductor wafer;
A swivelable loading / unloading means for loading the semiconductor wafer from the positioning means into the chuck table and unloading the processed wafer from the chuck table;
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 means having a spinner table for cleaning and spin drying a ground or polished semiconductor wafer;
A rotatable unloading means for unloading the semiconductor wafer cleaned and spin-dried by the spinner cleaning means from the spinner table to the next process;
The chuck table has first fixed point stop means for stopping rotation at a fixed position at the end of grinding or polishing,
The spinner cleaning means has a second fixed point stop means for stopping the rotation of the spinner table at a fixed position when the semiconductor wafer cleaning and spin drying are completed.
The cleaning means positions the mark in the same direction as when the semiconductor wafer is loaded onto the spinner table at the end of cleaning and spin drying of the semiconductor wafer, and then detects the mark of the semiconductor wafer detected by the alignment means. An apparatus for processing a semiconductor wafer, wherein the semiconductor wafer held on the spinner table is positioned in a predetermined direction based on the position, and is carried out to the next process by the transfer means. The mark indicating the crystal orientation of the semiconductor wafer is composed of a notch or a flat portion formed on the outer periphery of the semiconductor wafer, and the alignment means is above and below the outer peripheral portion of the semiconductor wafer held on the holding table. Provided with a light detector composed of a light emitting portion and a light receiving portion arranged opposite to each other,
3. The position of the mark is detected by receiving light from the light emitting unit with the light receiving unit while the semiconductor wafer is held and rotated on the holding table. Semiconductor wafer processing equipment.   The semiconductor wafer processing apparatus according to any one of claims 1 to 3, wherein the first and second fixed point stopping means are constituted by encoders.   The semiconductor wafer processing apparatus according to claim 1, wherein a positioning angle of the semiconductor wafer in the predetermined direction is determined based on angle information set in a next process.

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