JP5686570B2 - How to use wafer support plate - Google Patents

Description

  The present invention relates to a wafer support plate for supporting and transporting a wafer and a method of using the same.

  For example, in the semiconductor device manufacturing process, devices such as IC and LSI are formed in each region partitioned by streets (division lines) formed in a lattice shape on the surface of a semiconductor wafer having a substantially disk shape, Individual devices are manufactured by dividing each region in which the devices are formed along a division line.

  As a dividing device that divides a semiconductor wafer into individual devices, a cutting device generally called a dicing device is used. This cutting device uses a cutting blade having a very thin cutting edge to cut a semiconductor wafer along a planned dividing line. Cut the wafer into individual devices. Devices divided in this way are packaged and widely used in electric devices such as mobile phones and personal computers.

  In recent years, electric devices such as mobile phones and personal computers are required to be lighter and smaller, and thinner devices are required. As a technique for dividing a wafer into thinner devices, a dividing technique called a so-called first dicing method has been developed and put into practical use (for example, see Japanese Patent Application Laid-Open No. 11-40520).

  This tip dicing method is a semiconductor in which a dividing groove having a predetermined depth (a depth corresponding to the finished thickness of the device) is formed along the line to be divided from the surface of the semiconductor wafer, and then the dividing groove is formed on the surface. This is a technique for grinding the back surface of a wafer to expose a dividing groove on the back surface and dividing the wafer into individual devices. The thickness of the device can be processed to 50 μm or less.

  In the first dicing method, the wafer is half-cut without being completely cut, so there is no need to use a dicing tape that is used for full-cutting, and a dedicated cutting device for carrying out half-cutting is required to save dicing tape. It has been developed by the applicant (see JP 2004-235622 A).

JP 11-40520 A JP 2004-235622 A JP 2005-166969 A

  However, the cutting device dedicated to half-cutting as disclosed in Patent Document 2 is not versatile, and there is a problem that when half-cutting is not performed, operation is interrupted and productivity is poor. On the other hand, if the wafer is supported by the annular frame via the dicing tape, half-cutting can be performed using a general dicing tape, but there is a problem that it is uneconomical because it requires the use of a dicing tape.

  The present invention has been made in view of these points, and an object of the present invention is to provide a wafer support plate that does not require the use of a dicing tape when half-cutting the wafer, and a method for using the wafer support plate. is there.

According to the first aspect of the present invention, a chuck table having a holding surface on which a suction force for holding the wafer acts, a processing means for performing predetermined processing on the wafer held by the chuck table, and a wafer on the chuck table A wafer support plate for supporting and transporting a wafer, which is used in a processing apparatus comprising a first transport means for transporting wafers and a second transport means for transporting wafers from the chuck table , the wafer support plate, and the wafer supporting unit for supporting and accommodating the wafers formed from circular recess, and a plurality of through-holes formed in the bottom of the circular recess, surrounding the wafer support portion said of the processing device comprising a frame portion on which the first conveying means and second conveying means acts, and Bei cutting blade said processing means for performing cutting the wafer A wafer loading step in which the first conveying means acts on the frame portion of the wafer support plate in which the wafer is accommodated, and the wafer is loaded onto the holding surface of the chuck table; A holding step in which a suction force is applied to the holding surface to suck and hold the wafer through the plurality of through holes formed in the bottom of the circular recess, and a cutting groove is formed in the wafer supported by the wafer support plate by the processing means. And the second conveying means for unloading the wafer from the chuck table act on the frame portion of the wafer support plate, and the suction force acting on the holding surface of the chuck table is released to And a wafer unloading step for unloading the wafer from the chuck table. A method is provided.

  Preferably, an anti-slip sheet is disposed on the bottom of the circular recess.

  Preferably, the depth of the circular recess of the wafer support plate is set to be shallower than the distance from the bottom of the cutting groove formed in the wafer to the back surface of the wafer.

  By supporting the wafer with the wafer support plate of the present invention, the wafer can be half-cut without using a dicing tape and using a general dicing apparatus without using a dedicated cutting apparatus for carrying out half-cutting. It can be cut and is economical. Further, the wafer support plate of the present invention can be used repeatedly and is economical.

  Further, a laser processing apparatus that forms a split groove by irradiating the surface of the wafer with a laser beam having a wavelength that absorbs the wafer, and a laser beam having a wavelength that is transmissive to the wafer. The laser supporting apparatus of the present invention can also be used in a laser processing apparatus that collects and irradiates the inside of a wafer to form a modified layer inside the wafer, so that the use of a dicing tape can be avoided and it is economical. .

It is an external appearance perspective view of a cutting device. It is a disassembled perspective view which shows a mode that a wafer is supported by the wafer support plate of this invention embodiment. It is a perspective view of the state which supported the wafer with the wafer support plate. It is a longitudinal cross-sectional view of a wafer support plate. It is a perspective view which shows a mode that the wafer supported by the wafer support plate is cut.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. Referring to FIG. 1, there is shown an external perspective view of a cutting device 2 that can half-cut a wafer using the wafer support plate of the present invention.

  On the front side of the cutting device 2, there is provided operating means 4 for an operator to input instructions to the device such as machining conditions. In the upper part of the apparatus, there is provided a display means 6 such as a CRT for displaying a guidance screen for an operator and an image taken by an imaging means described later.

  As shown in FIGS. 2 and 3, on the surface of the device wafer W to be diced, the first street (division line) S1 and the second street (division line) S2 are formed orthogonally. A large number of devices D are formed on the wafer W by being partitioned by the first street S1 and the second street S2. Reference numeral 11 denotes a notch as a mark indicating the crystal orientation of the silicon wafer W.

  Referring to FIG. 2, there is shown an exploded perspective view showing how the wafer W is supported by the wafer support plate 30 of the embodiment of the present invention. The wafer support plate 30 has a circular recess 32 having a diameter slightly larger than the diameter of the wafer W, and a plurality of through holes 34 are formed at the bottom of the circular recess 32. Further, a protrusion 31 is formed which faces the circular recess 32 and fits into the notch 11 of the wafer W.

  The wafer support plate 30 has a frame portion 33 that surrounds the circular concave portion 32, and the wafer support plate 30 is conveyed by the conveying means of the cutting device 2 acting on the frame portion 33. The wafer support plate 30 is preferably formed from a resin, but may be formed from a metal such as aluminum.

  Since the wafer support plate 30 is used for half-cutting the wafer W, the depth of the circular recess 32 is set to be slightly shallower than the distance from the bottom of the cutting groove formed in the wafer W to the back surface of the wafer W. The For example, when the thickness of the wafer W is 700 μm and the depth of the cutting groove is 100 μm, the depth of the circular recess 32 is set to be shallower than 600 μm, for example, 500 μm.

  The circular recess 32 serves as a wafer support for supporting the wafer W, and the perspective view of the wafer W inserted into the circular recess 32 with the protrusion 31 of the wafer support plate 30 fitted into the notch 11 of the wafer W is shown. It is shown in FIG. Preferably, a non-slip sheet 36 is disposed at the bottom of the circular recess 32 that supports the wafer, as shown in the longitudinal sectional view of FIG.

  A plurality of through holes 37 communicating with the through holes 34 are also formed in the anti-slip sheet 36. By providing the anti-slip sheet 36 on the bottom of the circular recess 32 that functions as a wafer support portion, the wafer W is supported by the wafer support plate 30 and is prevented from jumping out of the circular recess 32 during conveyance.

  Referring again to FIG. 1, a plurality of wafers W supported by the wafer support plate 30 are accommodated in the wafer cassette 8. The wafer cassette 8 is placed on a cassette elevator 9 that can move up and down.

  Behind the wafer cassette 8, a loading / unloading means 10 for unloading the wafer W before cutting from the wafer cassette 8 and loading the wafer after cutting into the wafer cassette 8 is disposed.

  Between the wafer cassette 8 and the carry-in / out means 10, a temporary placement area 12, which is an area on which the wafer W to be carried in / out, is temporarily placed, is provided. Positioning means 14 is provided for aligning the position at a certain position.

  In the vicinity of the temporary placement area 12, a transport means 16 having a turning arm that sucks and transports the frame portion 33 of the wafer support plate 30 that supports the wafer W is disposed, and is transported to the temporary placement area 12. The wafer W is attracted by the conveying means 16 and conveyed onto the chuck table 18 and is sucked on the holding surface of the chuck table 18, and the frame portion 33 of the wafer support plate 30 is fixed by a plurality of clamps 19. As a result, the chuck table 18 is held.

  The chuck table 18 is configured to be rotatable and reciprocally movable in the X-axis direction. Above the movement path of the chuck table 18 in the X-axis direction, an alignment unit 20 that detects a street to be cut of the wafer W is provided. It is arranged.

  The alignment unit 20 includes an imaging unit 22 that images the surface of the wafer W, and can detect a street to be cut by a process such as pattern matching based on an image acquired by imaging. The image acquired by the imaging unit 22 is displayed on the display unit 6.

  On the left side of the alignment means 20, a cutting means 24 for cutting the wafer W held on the chuck table 18 is disposed. The cutting means 24 is configured integrally with the alignment means 20, and both move together in the Y-axis direction and the Z-axis direction.

  The cutting means 24 is configured by attaching a cutting blade 28 to the tip of a rotatable spindle 26 and is movable in the Y-axis direction and the Z-axis direction. The cutting blade 28 is located on the extended line of the imaging means 22 in the X-axis direction.

  The wafer W after the cutting is unloaded from the chuck table 18 by the transport means 25 and transported to the spinner cleaning device 27, and spin cleaning and spin drying are performed by the spinner cleaning device 27.

  Next, the usage method of the wafer support plate 30 of this embodiment comprised in this way is demonstrated. The wafer support plate is used in such a manner that the transport means 16 for transporting the wafer W acts on the frame portion 33 of the wafer support plate 30 in which the wafer W is accommodated and supported so that the wafer W is transported to the holding surface of the chuck table 18. A loading step and a holding step of sucking and holding the wafer W through a plurality of through holes 34 formed in the bottom of the circular recess 32 of the wafer holding plate 30 by applying a suction force to the holding surface of the chuck table 18. .

  Thus, after the wafer W is sucked and held by the chuck table 18 via the wafer support plate 30, a cutting process is performed in which the wafer W is cut by the cutting means (processing means) 24. This cutting process will be described with reference to FIG.

  Referring to FIG. 5, there is shown a perspective view of a state in which the wafer W supported on the wafer support plate 30 by the cutting means 24 is cut along the street. Reference numeral 25 denotes a spindle housing of the cutting means 24, and a spindle 26 that is rotationally driven by a servo motor (not shown) is rotatably accommodated in the spindle housing 25. The cutting blade 28 is an electroformed blade, and has a cutting edge 28a formed by dispersing diamond abrasive grains in a nickel base material on the outer periphery thereof.

  Reference numeral 40 denotes a blade cover that covers the cutting blade 28, and a cutting water nozzle (not shown) that extends along the side surface of the cutting blade 28 and cutting that sprays the cutting water onto the contact area between the cutting blade 28 a of the cutting blade 28 and the wafer W. A water injection nozzle 46 is attached.

  The cutting water from the cutting water supply unit 44 is supplied to a cutting water nozzle (not shown) via the pipe 42 and is supplied to the cutting water jet nozzle 46 via the pipe 48. The cutting water is pressurized to, for example, about 0.3 MPa by the cutting water supply unit 44 and is injected from the cutting water injection nozzle 46 at a flow rate of 1.6 to 2.0 liters per minute.

  Reference numeral 50 denotes a detachable cover, which is detachably attached to the blade cover 40 with screws 52. The detachable cover 50 has a cutting water nozzle 54 extending along the side surface of the cutting blade 28, and the cutting water is supplied to the cutting water nozzle 54 through a pipe 56.

  A blade detection block 60 includes a blade sensor for detecting chipping or wear of the cutting blade 28 a of the cutting blade 28, and is detachably attached to the blade cover 40 by screws 62. The blade detection block 60 has an adjustment screw 64 for adjusting the position of the blade sensor.

  Before the wafer W supported by the wafer support plate 30 is cut along the streets S1 and S2, the streets S1 and S2 to be cut and the cutting blade 28 are aligned by a well-known technique such as pattern matching. To do.

  After alignment, the first street S1 and the cutting blade 28 are aligned, the chuck table 18 is moved in the X-axis direction indicated by arrow X in FIG. 5, and the cutting blade 28 is rotated at high speed in the direction of arrow A. The cutting means 24 is lowered while being (for example, 30000 rpm), and a division groove having a predetermined depth (a depth corresponding to the finished thickness of the device) is formed in the aligned first street S1.

  The depth of the dividing groove is set to a depth that does not reach the upper surface of the frame portion 33 of the wafer support plate 30, for example, 100 μm. In this way, by cutting the wafer W halfway with the cutting blade 28, it is possible to form a division groove having a predetermined depth without damaging the wafer support plate 30.

  By performing cutting while indexing the cutting means 24 in the Y-axis direction by the street pitch stored in the memory, all the first streets S1 are half-cut, and similar divided grooves are formed. Further, when the chuck table 18 is rotated 90 degrees and then the same cutting is performed, the second street S2 is all half-cut to form the same divided groove.

  After the processing step for half-cutting all the streets S1 and S2 as described above, the suction force of the chuck table 18 is released, and then the suction portion of the transport means 25 is applied to the frame portion 33 of the wafer support plate 30 to obtain the wafer. The support plate 30 is sucked and held, transported to the spinner cleaning device 27, and the wafer W is spin cleaned and spin dried by the spinner cleaning device 27.

  Next, after attaching a protective tape to the surface of the wafer W, by grinding the back surface of the wafer on which the divided grooves are formed by a back surface grinding process using a grinding device, the divided grooves are exposed on the back surface. The wafer W can be divided into individual devices D.

  According to the above-described embodiment of the present invention, the wafer W is supported by the wafer support plate 30, so that a dicing can be further performed using a general dicing apparatus without using a dedicated cutting apparatus for performing a half cut. The wafer W can be half-cut without using a tape, which is very economical. Further, the wafer support plate 30 is economical because it can be used repeatedly.

  In the above-described embodiment, the example in which the wafer support plate 30 of the present invention is applied to the cutting apparatus 2 has been described. However, the wafer support plate 30 of the present invention is not limited to this method of use, and absorbs the wafer W. A laser beam processing apparatus that irradiates the surface of the wafer W with a laser beam having a wavelength to perform ablation processing to form a dividing groove, and a laser beam having a wavelength transparent to the wafer W is condensed inside the wafer W Thus, it can be used in the same manner for a laser processing apparatus that irradiates and forms a modified layer inside the wafer.

2 Cutting device 18 Chuck table 24 Cutting means 28 Cutting blade 30 Wafer support plate 32 Circular recess (wafer support)
33 Frame part 34 Through-hole

Claims (3)

A chuck table having a holding surface on which a suction force is applied to hold the wafer; a processing means for performing a predetermined processing on the wafer held by the chuck table; a first transport means for loading the wafer into the chuck table; It is used have you to machining apparatus and a second transfer means for unloading the wafer from the chuck table to a method of using the wafer support plate for wafer and the support conveyor,
The wafer support plate, and the wafer supporting unit for supporting and accommodating the wafers formed from circular recess, and a plurality of through-holes formed in the bottom of the circular recess, surrounding the wafer support portion said of the processing device A first transport means and a frame portion on which the second transport means acts ,
The processing means is composed of cutting means provided with a cutting blade for cutting the wafer ,
A wafer carry-in step in which the first carrying means acts on the frame portion of the wafer support plate in which a wafer is housed to carry the wafer onto the holding surface of the chuck table;
A holding step in which a suction force is applied to the holding surface of the chuck table to suck and hold the wafer through the plurality of through holes formed in the bottom of the circular recess;
A machining step that form a cut groove the wafer supported on the wafer support plate by the said processing means,
The second conveying means for unloading the wafer from the chuck table is applied to the frame portion of the wafer support plate, and the suction force acting on the holding surface of the chuck table is released to unload the wafer from the chuck table. Wafer unloading process,
A method for using a wafer support plate, comprising: 2. The method of using a wafer support plate according to claim 1, wherein an anti-slip sheet is disposed at the bottom of the circular recess. The depth of the circular recess of the wafer support plate, according to claim 1 or claim 2, wherein the wafer support plate, wherein the slightly shallower than the distance from the bottom of the cut groove to be formed on the wafer to the back surface of the wafer how to use.

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