JP5313022B2 - Workpiece cutting method - Google Patents

Description

  The present invention relates to a method for cutting a workpiece having a contact angle of 60 degrees or more with respect to pure water.

  A workpiece such as a wafer on which a plurality of imaging devices are formed and a substrate on which an optical device is formed is divided into individual devices by a cutting device, and the divided devices are widely used in various electric apparatuses.

  As the cutting device, for example, a dicer disclosed in Japanese Patent Application Laid-Open No. 11-74228 is provided, which includes a cutting blade in which superabrasive grains such as diamond and CBN (Cubic Boron Nitride) are hardened with metal, resin, glass or the like. Cutting devices are widely used.

  An adhesive tape as disclosed in, for example, Japanese Patent Application Laid-Open No. 2004-356435 is attached to the back surface of a workpiece to be cut by a dicer, and the outer peripheral portion of the adhesive tape is attached to an annular frame. The workpiece is supported by an annular frame via an adhesive tape.

  Usually, the adhesive tape is a base material made of PO (polyolefin), PVC (polyvinyl chloride) or the like having a thickness of about 100 μm, and an acrylic or rubber adhesive layer having a thickness of about 5 to 20 μm formed on the base material. The workpiece is stuck to the glue layer.

  The cutting blade cuts the work piece while cutting halfway in the thickness direction of the base material, so that the work piece that has been cut into a plurality of pieces is held on the adhesive tape without scattering. Kept.

  On the other hand, in order to cool the processing heat generated by the cutting and to discharge the cutting waste generated by the cutting from the workpiece, the dicer performs cutting while supplying cutting water to the processing point and the upper surface of the workpiece.

  In particular, if the workpiece is a substrate on which an optical device such as a wafer, filter, or optical pickup device with an imaging device such as a CMOS or CCD is formed, the device will fail if the scraps adhere to the device. Therefore, it is very important to prevent the attachment of cutting waste.

JP-A-11-74228 JP 2004-356435 A

  However, many of these imaging devices and optical devices generally have high water repellency (contact angle with respect to pure water of 60 degrees or more), and the upper surface of the workpiece dries during processing even when cutting while supplying cutting water. There is a tendency to end up.

  On the other hand, when cutting a workpiece with a cutting blade, in the conventional cutting method, the cutting blade cuts the workpiece while cutting halfway in the thickness direction of the base material. The adhesive layer of the tape and the cutting waste of the substrate are generated.

  When the water repellency of the workpiece is high, it is difficult to remove the cutting waste sufficiently during cutting while supplying cutting water. Tends to adhere to the upper surface of the work piece in a state in which cutting waste from the work piece or the substrate is taken in.

  Furthermore, the adhering cutting waste is dried and the cutting waste adheres to the upper surface of the work piece. Even if the work piece is washed in the cleaning process after cutting, the cutting waste cannot be removed, resulting in a device failure. Occurs.

  The present invention has been made in view of these points, and an object of the present invention is to provide a method for cutting a workpiece capable of cutting a workpiece with high water repellency without causing a device failure. That is.

  According to the present invention, there is provided a method for cutting a workpiece having a water repellency with a contact angle of 60 degrees or more with respect to pure water, the adhesive tape comprising a substrate and a glue layer on the back surface of the workpiece. A tape adhering step for adhering the adhesive layer side, an outer peripheral portion of the adhesive tape attached to an annular frame, and a supporting step for supporting the workpiece by the annular frame; and A holding step for holding by a chuck table of a cutting device via an adhesive tape, a positioning step for positioning the cutting blade at the height of the interface between the back surface of the workpiece and the glue layer, the cutting blade and the workpiece A cutting step of cutting the workpiece by relatively moving the cutting blade positioned at the height of the interface and the chuck table while supplying cutting water. How to cut the workpiece It is subjected.

  Preferably, the workpiece is composed of an imaging device such as a CMOS or CCD.

  According to the cutting method of the present invention, since the cutting blade cuts without cutting into the adhesive layer of the adhesive tape, the cutting waste of the adhesive layer does not occur, and the cutting waste of the adhesive layer does not form the workpiece or the base as in the conventional case. Adhering to the upper surface of the work piece in a state where the cutting scraps of the material are taken in can be prevented, and the adhesion of the cutting scraps can be reduced.

It is an external appearance perspective view of the cutting device suitable for implementing the cutting method of this invention. It is the surface side perspective view of the semiconductor wafer supported by the annular frame via the adhesive tape. It is a side view of a cutting blade and a wheel cover part. It is sectional drawing which shows the cutting method of this invention embodiment. It is a figure which shows the area | region which counted the adhesion number of the cutting waste in this invention Example and the comparative example. It is a graph which shows the number of cutting waste adhesion of an Example and Comparative Examples 1 and 2.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. FIG. 1 shows an external view of a cutting apparatus 2 that cuts a semiconductor wafer and divides it into individual chips (devices) suitable for carrying out the cutting method 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 FIG. 2, on the surface of the wafer W to be diced, the first street S1 and the second street S2 are formed orthogonally, and the first street S1 and the second street S2 A large number of devices D are formed on the wafer W.

  The wafer W is attached to a dicing tape T that is an adhesive tape, and the outer peripheral edge of the dicing tape T is attached to an annular frame F. As a result, the wafer W is supported by the frame F via the dicing tape T, and a plurality of wafers (for example, 25 sheets) are accommodated in the wafer cassette 8 shown in FIG. 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 loading / unloading means 10, a temporary placement area 12, which is an area on which a wafer to be carried in / out, is temporarily placed, is provided. Positioning means 14 for positioning at a certain position is provided.

  In the vicinity of the temporary placement area 12, transport means 16 having a turning arm that sucks and transports the frame F integrated with the wafer W is disposed, and the wafer W carried to the temporary placement area 12 is It is sucked by the transport means 16 and transported onto the chuck table 18 and is sucked by the chuck table 18 and is held on the chuck table 18 by fixing the frame F by a plurality of clamps 19.

  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.

  Referring to FIG. 3, a side view of the cutting blade and wheel cover portion is shown. A wheel cover 30 covers the cutting blade 28, and a blade breakage detector 32 is attached to the wheel cover 30.

  The blade breakage detector 32 is positioned so that the tip of the light emitting part 34 connected to the optical fiber 36 and the tip of the light receiving part similarly connected to the optical fiber face each other across the cutting blade 28a of the cutting blade 28. Configured.

  Reference numeral 38 denotes an adjusting screw for adjusting the position of the blade breakage detector 32, and reference numeral 40 denotes a fixing screw for fixing the blade breakage detector 32 at the adjusted position. A marker 42 is formed at the tip of the light emitting unit 34.

  A cooling nozzle assembly 44 is attached to the blade cover 30. The cooling nozzle assembly 44 includes a connection pipe 46 to which the hose 50 is connected, and a pair of cooling nozzles 48 branched from the connection pipe 46 and disposed on both sides of the cutting blade 28. A splash cover 52 is provided outside each cooling nozzle 48.

  A nozzle block 56 is fastened to the wheel cover 30 by screws 58. The nozzle block 56 has a shower nozzle 60 that supplies cutting water to the tip of the cutting blade 28 and a spray nozzle 62 that supplies cutting water to the upper surface of the workpiece after cutting.

  The shower nozzle 60 is connected to a hose 66 via a connection pipe 64, and the spray nozzle 62 is connected to a hose 70 via a connection pipe 68. Each hose 50, 66, 70 is connected to a cutting water source (not shown).

  When cutting the workpiece, a predetermined amount of cutting water is supplied from the shower nozzle 60 toward the cutting edge 28a of the cutting blade 28, and a predetermined amount of cutting water is supplied from the cooling nozzle 48 to the lower side of the side surface of the cutting blade 28. The workpiece is cut while supplying a predetermined amount of cutting water from the spray nozzle 62 to the upper surface of the workpiece after cutting.

  The cutting method for a workpiece of the present invention is a cutting method particularly suitable for a workpiece having a water repellency with a contact angle of 60 degrees or more with respect to pure water. As shown in FIG. 4, the wafer W is a wafer having an imaging device such as a CMOS or CCD formed on its surface, has a contact angle of 60 degrees or more with respect to pure water, and has a very high water repellency. Work piece.

  In the cutting method of the present invention, the adhesive layer 31 side of the pressure-sensitive adhesive tape T composed of the base material 29 and the adhesive layer 31 is first attached to the back surface of the wafer W that is a workpiece. The outer peripheral portion of the adhesive tape T is adhered to the annular frame F, whereby the wafer W is supported by the annular frame F via the adhesive tape T.

  The cutting means 24 includes a spindle 26 rotatably accommodated in a spindle housing 33, and a cutting blade 28 attached to the tip of the spindle 26. The spindle 26 is rotated at a high speed such as 30000 rpm by a motor (not shown). Is done.

  The wafer W supported by the annular frame F is mounted on the chuck table 18 and sucked and held via the adhesive tape T, and the annular frame F is fixed by a clamp 19.

  In the cutting method of the present invention, the cutting blade 28 is positioned at the height position of the interface between the back surface of the wafer W and the adhesive layer 31 of the adhesive tape T as shown in FIG.

  Next, while supplying a predetermined amount of cutting water from the shower nozzle 60, the cooling nozzle 48 and the spray nozzle 62 to the cutting blade 28 and the wafer W, the chuck table 18 is moved in the X-axis direction with respect to the cutting blade 28 in FIG. Then, the wafer W is cut along the street S1 or S2.

  The cutting method of the present invention is characterized in that in the conventional cutting method, the cutting blade 28 cuts the wafer W while cutting in the middle of the thickness direction of the base material 29 of the adhesive tape T, whereas the cutting blade 28 is used as a wafer. Cutting is performed at the height position of the interface between the back surface of the W and the adhesive layer 31, and cutting is performed without generating cutting waste of the adhesive layer 31.

  The workpiece was cut under the following processing conditions using the following cutting blade and adhesive tape, and cleaned with a spinner cleaning device. The workpiece after washing was measured using the following measuring device.

Used cutting device: DFD6340 manufactured by DISCO Corporation
Cutting blade: Hub type blade made by DISCO Corporation ZH05-SD2000-N1-90 FF
Workpiece: 8 inch Si wafer with resin film with a contact angle of 60 degrees or more with respect to pure water Adhesive tape: D-650 manufactured by Lintec Corporation
Processing conditions:
Feed rate 30mm / sec
Spindle speed 30000rpm
Index size 5 × 5mm
Cutting water volume (shower nozzle) 2.0L / min
Cutting water volume (cooling nozzle) 1.0L / min
Cutting water volume (spray nozzle) 1.0L / min
Cleaning conditions:
Cleaning type Two-fluid cleaning with water and air
Water volume 200mL / min
Air pressure 0.4 MPa
Cleaning time 100 seconds
Cleaning table rotation speed 800rpm
Drying time 100 seconds
Table rotation speed during drying 2000rpm
Measuring method:
Microscope MF-UA1020THD manufactured by Mitutoyo Corporation
Objective lens BD Plan Apo 20 × / 0.42
CCD camera Ikegami Tsushinki Co., Ltd. SKC-151
Image processing software First made FV-Pixelence
Setting threshold 5
In the experiment of Example 1, five points A, B, C, D, and E are selected on the upper surface of the wafer W as shown in FIG. Counted the number. The result is shown in FIG.

(Comparative Example 1)
The cutting depth of the cutting blade 28 to the adhesive tape T is set to 20 μm, and other conditions are cut in the same state as in the above-described embodiment. The number of chips attached was counted. The result is shown in FIG.

(Comparative Example 2)
The cutting depth of the cutting blade 28 into the adhesive tape T was set to 5 μm, and other conditions were cut in the same manner as in the above-described example. As in the example, the number of chips attached to the 5 visual fields at 5 points A to E was counted. The result is shown in FIG.

  As apparent from the graph showing the experimental results in FIG. 6, according to the cutting method of the embodiment of the present invention, the number of chips attached is remarkably reduced as compared with Comparative Example 1 and Comparative Example 2. I can see it.

  In the embodiment of the present invention, since the wafer W is cut by positioning the cutting blade 28 at the interface between the back surface of the wafer W and the glue layer 31, the glue layer 31 hardly generates cutting waste. This is considered to be because the cutting waste does not adhere to the surface of the wafer W in a state where the cutting waste of the wafer W or the cutting waste of the base material 29 is taken in.

W Wafer T Adhesive tape F Annular frame 28 Cutting blade 29 Base material 31 Adhesive layer

Claims (2)

A method of cutting a workpiece having a water repellency of 60 ° or more with respect to pure water,
A tape adhering step for adhering the adhesive layer side of an adhesive tape composed of a base material and an adhesive layer to the back surface of the workpiece;
A support step of attaching an outer peripheral portion of the adhesive tape to an annular frame and supporting the workpiece with the annular frame;
A holding step for holding the workpiece on the chuck table of the cutting device via the adhesive tape;
A positioning step of positioning a cutting blade at the height of the interface between the back surface of the workpiece and the glue layer;
A cutting step of cutting the workpiece by relatively moving the cutting blade positioned at the height of the interface and the chuck table while supplying cutting water to the cutting blade and the workpiece; ,
A method for cutting a workpiece, comprising:   The method of cutting a workpiece according to claim 1, wherein the workpiece is configured by an imaging device.

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