JP2007229831A - Cutting method by dicing blade - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a cutting method for a dicing blade capable of extraordinarily reducing a generation percentage of defective cut portions, and improving a production yield only by properly performing initial setting of cut conditions without causing productivity degradation due to an increase in the number of processes. <P>SOLUTION: This is a cutting method using the dicing blade 10 rotated and driven by a dicing device along a dicing line 101 formed for partitioning and forming a plurality of optical parts piece regions 102 with small area on a surface of an optical substrate wafer 100. Dicing is performed under the cutting conditions described below: (a) Concentration ratio of the blade: 50-60, (b) Dicing tape adhesive material: acrylic UV hardened type, Adhesive thickness: 5-8 μm, Adhesive strength before UV irradiation: 4-7 N/20 mm, Adhesive strength after UV irradiation: 0.37 N/20 mm, (c) Rotational speed of dicing blade: 27,000-30,000 rpm, Feed rate of dicing blade: 10-14 mm/sec. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  In the process of mass-producing optical components using a large-area optical substrate wafer such as a glass substrate wafer, the present invention can greatly reduce the incidence of defective cutting locations on the wafer cutting surface without reducing productivity. The present invention relates to a cutting method using a dicing blade.

Conventionally, when mass-producing an optical component having an optical thin film pattern on an optical substrate surface such as a glass substrate, for example, a photolithographic technique on each optical component individual region on a large-area glass substrate wafer surface An optical thin film pattern is formed using an etching technique. At this time, linear dicing lines composed of optical thin film patterns are formed in a lattice shape along the boundary lines of the individual regions. By cutting along the dicing line, the glass substrate wafer is divided into optical component pieces.
FIGS. 5A and 5B are a plan view and a front view showing a state where the glass substrate wafer 100 is bonded to the center of the upper surface of a dicing tape (wafer bonding tape) 102.
Dicing lines 101 are formed in a lattice pattern on the surface of the wafer 100, and the lower surface of the wafer 100 is bonded and held on an adhesive layer provided on the upper surface of the dicing tape 103.

  6 (a) and 6 (b) show a procedure for fixing the dicing tape 103 by the inner and outer ring members 110 and 111 as a pre-stage operation for mounting the glass substrate wafer and tape shown in FIG. Show. The small-diameter inner ring member 110 has an outer diameter dimension that can be fitted to the inner periphery of the large-diameter outer ring member 111, and has an outer diameter dimension that is larger than the outer diameter of the wafer 100. First, as shown in FIG. 6A, after the dicing tape 103 holding the wafer 100 at the center is placed on the upper surface side of the inner ring member 110, the outer peripheral surface of the inner ring member 110 and the outer ring member 111 are The outer ring member 111 is fitted to the outer periphery of the inner ring member 110 and fixed so that the dicing tape 103 is sandwiched between the inner peripheral surface and the inner peripheral surface. Thus, by sandwiching the dicing tape 103 between the inner and outer ring members 110 and 111, the wafer 100 is fixed to the upper surface of the inner and outer ring members.

  FIG. 7A is a schematic diagram showing a state in which an optical substrate wafer is cut by a conventional dicing apparatus. In this dicing apparatus, the wafer 100 is rotationally driven by a water-cooled spindle motor 121 while the inner and outer ring members 110 and 111 holding the wafer 100 shown in FIG. The disc-shaped dicing blade 122 cuts along the dicing line 101. After the cutting of the vertical dicing line is completed, the stage 120 is rotated by 90 degrees to cut the horizontal dicing line. During cutting, cutting water is supplied while moving the spindle motor 121 at a predetermined feed speed so that the cutting edge of the dicing blade 122 moves along the dicing line while supplying cutting water made of pure water or the like to the cutting location. To do. The cutting depth by the dicing blade is set such that the wafer 100 is fully cut while the dicing tape 103 positioned immediately below the wafer 100 is half-cut.

The spindle motor 121 has a built-in cooling water circulation path (not shown) and is configured to appropriately cool the heat generating portion.
The dicing blade 122 has a configuration in which diamond grains are dispersed in a resin binder, and the dispersion density of diamond grains in the resin binder is referred to as the degree of concentration of the blade. Further, as shown in FIG. 7B, the dicing blade 122 has a configuration in which a predetermined range is supported by a disk-shaped support plate 122b from the center of both surfaces of the blade body 122a. The length L up to the tip of the main body 122a is referred to as a tooth extension amount.
The dicing tape 103 has a configuration in which an adhesive layer is formed on one side of a base material.

The operation of cutting the wafer 100 on the dicing tape 103 using the dicing apparatus having the above configuration is performed under the following conditions, for example.
(A) Dicing blade Product name: SDC400GEBNR (manufactured by Noritake)
Blade concentration: 75
Denture amount: 1.2 to 2.4 mm
(B) Dicing tape Product name: NBD-5170K (manufactured by Nitto Denko Corporation)
Substrate material: polyolefin, substrate thickness: 150 μm,
Adhesive material: acrylic UV curable adhesive, adhesive thickness: 20 μm,
Adhesive strength before UV irradiation: 14.7 N / 20 mm, adhesive strength before UV irradiation: 0.15 N / 20 mm
(C) Dicing device Number of rotations of dicing blade: 30000 rpm
Feeding speed of dicing blade: 10mm / sec
(D) Cutting water: pure water

However, in the wafer cutting process under such conditions, as shown in the enlarged view of the cutting portion in FIG. 7C, a cutting defect portion 100a such as a chipped portion or a chipping portion is generated on the cut surface of the wafer. The yield was only around 93%.
When the present inventor investigated the cause of the occurrence of such a defective cutting portion, it was found that there was a problem in the concentration of the blade, the material and thickness of the substrate of the dicing tape, and the thickness of the adhesive.
That is, the inventor has first determined that when the blade concentration is 75, the cutting resistance increases and the sharpness decreases, and as a result, a defective cutting portion is likely to occur.

Next, if the material of the dicing tape base material is soft like polyolefin as described above and the base material thickness is as thick as about 150 μm, the wafer tends to vibrate and swing due to the pressure from the blade during cutting, As a result, it was clarified that a defective cutting portion is likely to occur on the cut surface. Similarly, when the thickness of the adhesive is about 20 μm, it has been found that cutting failure occurs for the same reason.
As described above, in each conventional cutting condition, the frequency of occurrence of defective cutting increases, so there is a limit to increasing the feeding speed of the dicing blade, and it is difficult to improve productivity with a feeding speed exceeding 10 mm / sec. It was.

In Patent Document 1, a substrate fixed on a dicing table is arranged along parallel dicing lines so as not to cause chipping when the substrate bonded on the UV adhesive tape is cut into individual pieces by a dicing apparatus. A method of filling a groove, which is formed after cutting, with a resist as a fixing material, then rotating the dicing table 90 degrees, cutting along the remaining dicing lines, and then dissolving and separating the resist Is disclosed.
However, it is clear that productivity is significantly reduced by increasing the number of steps of filling the groove formed after cutting with a resist and the step of cleaning the resist.
JP 2005-254336 A

As described above, in the optical substrate wafer cutting method using the conventional dicing apparatus, the blade concentration, the material and thickness of the dicing tape base material, and the thickness of the adhesive were not set appropriately. There is a problem in that the manufacturing yield is greatly reduced as a result of the occurrence of cutting defects such as flickering spots and chipping spots on the cut surface of the wafer, which limits the speeding up of the feeding speed of the dicing blade. Increasing the number of steps, such as filling the cutting groove with a fixing material, can solve this problem, but there is a problem in that productivity is greatly reduced.
The present invention has been made in view of the above, and can be manufactured by significantly reducing the occurrence rate of defective cutting points by simply performing the initial setting of cutting conditions without causing a decrease in productivity due to an increase in the number of processes. It aims at providing the cutting method of the dicing blade which can improve a yield.

In order to achieve the above object, a cutting method using a dicing blade according to the present invention is performed along a dicing line formed to partition a plurality of small-area optical component piece regions on the surface of an optical substrate wafer. , A method of cutting with a dicing blade rotated by a dicing device,
The following cutting conditions (a) Dicing blade Concentration of blade: 50-60
Denture amount: 1.2 to 2.4 mm
(B) Dicing tape Substrate material: PVC, substrate thickness: 150-190 μm,
Adhesive material: acrylic UV curable, adhesive thickness: 5-8 μm,
Adhesive strength before UV irradiation: 4 to 7 N / 20 mm, Adhesive strength after UV irradiation: 0.37 N / 20 mm
(C) Dicing device Number of rotations of dicing blade: 27000-30000 rpm
Feeding speed of dicing blade: 10-14mm / sec
Based on the above, dicing is performed.
By reducing the concentration of the dicing blade from the conventional 75 to the range of 50 to 60, it was possible to reduce the cutting resistance and improve the sharpness. In addition, since a harder material is used as the adhesive that constitutes the dicing tape and the thickness of the adhesive is reduced, the wafer is less likely to vibrate and swing on the tape substrate due to the pressure from the dicing blade. It became hard to generate the defective cutting part. It has been found that a dicing tape is preferably a hard material rather than a soft material.

Further, the cutting method using the dicing blade according to the present invention is rotated by a dicing device along a dicing line formed for partitioning a plurality of small-area optical component individual regions on the surface of the optical substrate wafer. A method of cutting with a driven dicing blade,
The following cutting conditions (a) Dicing blade Concentration of blade: 50-60
Denture amount: 1.2 to 2.4 mm
(B) Dicing tape Substrate material: polyolefin, substrate thickness: 150-190 μm,
Adhesive material: acrylic UV curable, adhesive thickness: 5-8 μm
Adhesive strength before UV irradiation: 4 to 7 N / 20 mm, Adhesive strength after UV irradiation: 0.37 N / 20 mm
(C) Dicing device Number of rotations of dicing blade: 27000-30000 rpm
Feeding speed of dicing blade: 10-14mm / sec
Based on the above, dicing is performed.
Even when the thickness of the adhesive laminated on the tape is reduced to about 5 to 8 μm, when the base material is polyolefin and the base material thickness is 150 to 190 μm, a sufficient cutting failure prevention effect is obtained. It was found that

Hereinafter, the present invention will be described in detail with reference to embodiments shown in the drawings.
1A, 1B, 1C, and 1D are plan views of an optical substrate wafer provided with a dicing line according to an embodiment of the present invention, and a plan view showing a state in which the wafer is bonded onto a dicing tape. FIG. 2 is a view showing a state in which a wafer is fixed by a front view and a ring member, and FIG. 2 is a view showing a state in which the wafer is cut by a dicing apparatus.

The optical substrate wafer 100 is a large-area glass substrate wafer used for mass production of an optical component having an optical film formed on, for example, a glass substrate. Dicing is performed on the surface of the glass substrate wafer 100 by photolithography technology. A line 101 is formed in a lattice shape, a required optical film is formed on each surface of the optical component piece region 102 surrounded by the dicing line 101, and then cut along the dicing line 101 by the dicing blade 10. An optical component piece can be obtained by dividing. Alternatively, the material exists without using a special film for forming the dicing line 101 and using a highly visible material such as a metal film that forms a boundary line between each optical component individual region as a mark. It is also possible to recognize the wafer surface not to be processed as a dicing line.
In other words, the dicing line 101 is formed on the surface of the large-area glass substrate wafer 100 in order to partition and form a plurality of small-area optical component piece regions 102 and serves as a guide when cutting with the dicing blade 10. This is a boundary line that defines between the optical component individual regions 102 that are visible.

The wafer 100 is bonded and fixed to the central portion of the adhesive surface 1b formed on one surface of the base material 1a of the dicing tape 1 as shown in FIG.
Since the dicing tape 1 holding the wafer 100 is sandwiched and fixed between the inner and outer ring members 110 and 111 as in the case of FIG. 6, the wafer 100 is fixed to the upper surface of the ring member.

  The dicing apparatus shown in FIG. 2 is a water-cooled spindle motor 121 in which the inner and outer ring members 110 and 111 holding the wafer 100 shown in FIG. Is cut along the dicing line 101 by the disc-shaped dicing blade 10 that is rotationally driven by After the cutting of the vertical dicing line is completed, the stage 120 is rotated by 90 degrees to cut the horizontal dicing line. During cutting, cutting water is supplied while moving the spindle motor 121 at a predetermined feed speed so that the cutting edge of the dicing blade 10 moves along the dicing line while supplying cutting water made of pure water or the like to the cutting location. To do. The cutting depth by the dicing blade 10 is set to such an extent that the wafer 100 is fully cut while the dicing tape 1 positioned immediately below the wafer 100 is half-cut.

The spindle motor 121 includes a cooling water circulation path (not shown) and is configured to cool the heat generating portion as appropriate.
Of course, the method of holding the wafer on the stage 120 is not limited to the above example, and various fixing methods can be adopted.
The dicing blade 122 has a configuration in which diamond grains are dispersed in a resin binder, and the dispersion density of diamond grains in the resin binder is referred to as the degree of concentration of the blade. Further, as shown in FIG. 3, the dicing blade 10 has a configuration in which a predetermined range from the center of both surfaces of the blade body 10a is supported by a disk-like support plate 10b, and the blade body 10a has an outer peripheral edge. The length L to the tip is referred to as the amount of tooth protrusion.

When the present inventor has studied various cutting conditions when the wafer is cut by the dicing blade 10 that is rotationally driven by the dicing apparatus, the cutting method performed under the following cutting conditions has the lowest occurrence rate of defective cutting portions. I came to find.
As a result, in each item such as the configuration of the dicing device (including the temperature of the spindle motor cooling water), the amount L of the blade teeth, and the type of the cutting water, the cutting conditions are the same as those in the conventional example shown in FIG. However, by changing other cutting conditions such as the concentration of the dicing blade and each item of the dicing tape configuration as follows, the feed speed of the dicing blade is increased (or the rotation speed is reduced) ), It has been found that it is possible to carry out highly productive work with few cutting defects (yield 99%).

FIGS. 4A to 4F are diagrams showing the results of experiments on the blade concentration, the tape base material thickness, the adhesive thickness, the adhesive strength before UV irradiation, the blade rotation speed, and the blade feed speed.
Optimal cutting conditions (a) Dicing blade Product name: SDC400GEBNR (manufactured by Noritake)
Blade concentration: 50-60 (55 is particularly preferred)
Denture amount: 1.2 to 2.4 mm
(B) Dicing tape Product name: NBD1200X (manufactured by Nitto Denko Corporation)
Substrate material: PVC, substrate thickness: 150-190 μm (especially 175 μm is preferred)
Adhesive material: acrylic UV curable, adhesive thickness: 5-8 μm (especially 5 μm is preferred),
Adhesive strength before UV irradiation: 4 to 7 N / 20 mm (particularly 5.3 N / 20 mm is preferable), Adhesive strength after UV irradiation: 0.37 N / 20 mm
(C) Dicing machine Product name: NBD-5170K (manufactured by Nitto Denko Corporation)
Number of rotations of dicing blade: 27000-30000 rpm (particularly 30000 rpm is preferable)
Feeding speed of dicing blade: 10 to 14 mm / sec (especially 13 mm / sec is preferable)
(D) Cutting water: pure water

The reason why the defective cutting portion is less likely to occur due to the cutting conditions according to the present invention is as follows.
First, the cutting resistance can be reduced by reducing the concentration level of the dicing blade from the conventional 75 to the range of 50 to 60 (especially 55). Easy to get.
Next, since a harder material is used as the adhesive 1b constituting the dicing tape 1 and the thickness of the adhesive is reduced, the wafer is less likely to vibrate and swing on the tape substrate 1a due to the pressure from the dicing blade. As a result, it becomes difficult to generate defective cutting portions. It has been found that a dicing tape is preferably a hard material rather than a soft material. However, even when a dicing tape having a base material of polyolefin and a base material thickness of 150 to 190 μm is used, the thickness of the adhesive laminated on the tape is reduced to about 5 to 8 μm (particularly 5 μm). In some cases, it was found that a sufficient cutting failure prevention effect was obtained.

  Due to the above-mentioned condition setting, it has become difficult for defective cutting parts to occur, so even though the dicing blade rotation speed is the same, the feeding speed is further increased, the defective product rate is reduced, and the productivity is reduced. It became possible to improve.

(A) (b) (c) and (d) is a plan view of an optical substrate wafer provided with a dicing line according to an embodiment of the present invention, a plan view showing a state in which this wafer is bonded onto a dicing tape, and a front view. It is a figure which shows the state which fixed the wafer with the figure and the ring member. It is a figure which shows the state which has cut | disconnected the wafer with the dicing apparatus. (A) And (b) is a structure explanatory drawing of a dicing blade. (A) thru | or (f) is a figure which shows the result of the experiment regarding a blade concentration degree, tape base material thickness, adhesive agent thickness, adhesive force before UV irradiation, a blade rotation speed, and a blade feed speed. (A) And (b) is the top view which shows the state which adhere | attached the glass substrate wafer to the upper surface center part of the dicing tape, and a front view. (A) And (b) is a figure which shows the procedure which fixes a dicing tape by the inner and outer ring members. (A) is the schematic which shows the state which cut | disconnects an optical substrate wafer with the conventional dicing apparatus, (b) is a structure explanatory drawing of a dicing blade, (c) is an enlarged view of a cutting part.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 ... Dicing tape, 1a ... Base material, 1b ... Adhesive surface, 10 ... Dicing blade, 10a ... Blade main body, 10b ... Support plate, 100 ... Glass substrate wafer, 100a ... Cutting defect location, 101 ... Dicing line, 102 ... Optical component individual region 103: Dicing tape 110, 111 ... Ring member 120 ... Stage 121 ... Spindle motor 122 ... Dicing blade 122a ... Blade body 122b ... Support plate

Claims (2)

A method of cutting with a dicing blade that is rotationally driven by a dicing device along a dicing line formed for partitioning a plurality of small-area optical component individual regions on the surface of the optical substrate wafer,
The following cutting conditions (a) Dicing blade Concentration of blade: 50-60
Denture amount: 1.2 to 2.4 mm
(B) Dicing tape Substrate material: PVC, substrate thickness: 150-190 μm,
Adhesive material: acrylic UV curable, adhesive thickness: 5-8 μm,
Adhesive strength before UV irradiation: 4 to 7 N / 20 mm, Adhesive strength after UV irradiation: 0.37 N / 20 mm
(C) Dicing device Number of rotations of dicing blade: 27000-30000 rpm
Feeding speed of dicing blade: 10-14mm / sec
A cutting method using a dicing blade, characterized in that dicing is performed based on the above. A method of cutting with a dicing blade that is rotationally driven by a dicing device along a dicing line formed for partitioning a plurality of small-area optical component individual regions on the surface of the optical substrate wafer,
The following cutting conditions (a) Dicing blade Concentration of blade: 50-60
Denture amount: 1.2 to 2.4 mm
(B) Dicing tape Substrate material: polyolefin, substrate thickness: 150-190 μm,
Adhesive material: acrylic UV curable, adhesive thickness: 5-8 μm
Adhesive strength before UV irradiation: 4 to 7 N / 20 mm, Adhesive strength after UV irradiation: 0.37 N / 20 mm
(C) Dicing device Number of rotations of dicing blade: 27000-30000 rpm
Feeding speed of dicing blade: 10-14mm / sec
A cutting method using a dicing blade, characterized in that dicing is performed based on the above.

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