JPH0684855A - Cutting-off of substrate as well as method and apparatus for chamfering - Google Patents

Abstract

PURPOSE:To cut off a small-diameter substrate form a large-diameter wafer with high accuracy by a method wherein the central hole and the outer circumference of a substrate are cut off simultaneously to be a concentric circle shape by a laser beam. CONSTITUTION:Light-projecting positions of a laser beam 30 are aligned with positions corresponding to the inner circumference of a central hole 18 and the outer circumference 19 of a substrate 14 to be cut off. A first motor is driven, a wafer 12 is turned around the center of the central hole 18 in the cutting-off position, and the substrate 14 is cut off. The substrate 14 is aligned with positions coupled to chamfering whetstones 9, 10. A chamfering-whetstone driving mechanism part 11 is actuated, the chamfering whetstones 9, 10 are brought into contact with the outer circumference 19 and the suction hole 18, and edge parts 32, 31 are chamfered and worked. Thereby, the substrate whose concentricity is high is formed and the eccentricity of the central hole from the outer circumference can be eliminated.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method and apparatus for cutting and chamfering a magnetic recording medium substrate (hereinafter referred to as substrate) such as a magnetic disk substrate.

[0002]

2. Description of the Related Art With the progress of the information society, a large-capacity magnetic recording medium is required, and in particular, a magnetic disk, which plays a central role as an external memory of a computer, is increasing in recording capacity and recording density year by year. However, the development for higher density recording is underway. In particular,
With the development of laptops and palmtop computers, compact and shock-resistant recording devices are desired.
There is a demand for a magnetic recording medium capable of higher density recording and having higher mechanical strength.

As a substrate for a magnetic disk which is this magnetic recording medium, an aluminum alloy and NiP on the surface thereof are used.
Conventionally, plated products and glass substrates have been used. However, the aluminum alloy substrate has poor wear resistance and workability, and NiP plating treatment is performed to compensate for this drawback. However, the NiP plating treatment causes warpage and is magnetized at high temperature. And the like. Further, the glass substrate has a problem that a strained layer is generated on the surface during the strengthening treatment, a compressive stress acts, and a warp is likely to occur when the substrate is heated.

On the other hand, single crystal silicon has good high temperature characteristics,
Since it has many advantages such as a small coefficient of thermal expansion, a specific gravity smaller than that of aluminum, and conductivity, it is an optimal substrate material.

[Problems to be Solved by the Invention]

FIG. 7 shows an outline of a substrate manufacturing method. As shown in the figure, the substrate 56a is made of a thin disk having a diameter d ₁ and having a central hole 54a for inserting and clamping the rotary shaft in the center. As a method of manufacturing the substrate 56a, first, a single crystal silicon rod 50 having a diameter d ₁ is made.
Next, a boring process for boring the through hole 51 corresponding to the center hole 54a is performed. The single crystal silicon rod 50 having the through holes 51 is sliced into a predetermined thickness. The sliced donut-shaped disk 53a is chamfered by a grindstone (not shown) at the center hole 54a and the outer peripheral edge, and then the front and back surfaces thereof are lapped and finish-polished. Finally, the substrate 56a is completed by cleaning to remove the polishing agent and the like.

However, in the above method, since finish processing is performed in units of small-diameter substrates, productivity is poor, and there is a problem that when the slicing speed is increased to increase productivity, warpage becomes large. . On the other hand, the central hole 54a and the outer periphery must be formed as concentric disks. That is, the substrate 56a is rotated by inserting the rotation shaft into the center hole 54a, but if the center hole 54a and the outer periphery are eccentric, the center of gravity is deviated, and the rotation of the substrate 56a becomes unstable.

In addition, in order to increase the recording capacity, it is desired to perform recording to the outer circumference of the magnetic disk as much as possible, but if the concentricity between the inner circumference and the outer circumference of the substrate is poor, it becomes a rule at the shortest distance between the inner circumference and the outer circumference of the substrate. , The outside can no longer be used. However, in the conventional manufacturing method shown in FIG. 7, since the center hole 54a is formed in the state of the single crystal silicon rod 50, hole bending is likely to occur, and the cutting resistance at the time of hole processing becomes uneven, resulting in high accuracy. It becomes difficult to maintain the concentricity of.

In order to solve this, the present inventors have studied a method of cutting a small-diameter substrate from a large-diameter wafer. At that time, in order to prevent chipping of the center hole and the outer periphery of the cut substrate, it was attempted to chamfer the edges of the substrate in a separate step with a chamfering grindstone or the like. However, if the chamfering of the cut-out substrate is performed by another chamfering machine, etc., the center alignment between the chamfering grindstone of the chamfering machine and the cut-out substrate is required, and the cutting allowance must be increased in some cases, There was a problem that processing efficiency was poor. Furthermore, since the cutting and chamfering processes are performed separately, the production efficiency is poor, and much loading and unloading time and manpower are required. Further, there has been a problem that a great number of man-hours are required for repairing a substrate having a large amount of eccentricity.

The present invention solves the above problems and is capable of highly accurately cutting a small-diameter substrate from a large-diameter wafer, with less eccentricity, less carry-in / out loss between processes, and productivity. It is an object of the present invention to provide a method and an apparatus for cutting and chamfering a substrate, which can improve the performance.

[0010]

In order to achieve the above object, the present invention cuts out a small-diameter substrate having a central hole from a large-diameter wafer and chamfers the central hole and the outer peripheral edge. A method of adsorbing the wafer at the cutting position, rotating the wafer around the center of the substrate cut out from the wafer, and irradiating the laser beam with the edge of the central hole of the substrate and its outer periphery. After cutting out the doughnut-shaped substrate, the substrate is moved to the chamfering position while the substrate is adsorbed, and the center hole and the peripheral edge are chamfered.
At the same time, a wafer obtained by cutting the substrate or a new wafer is positioned at the cutting position of the substrate, and cutting is performed by laser light.

As an apparatus for carrying out this method, an apparatus for cutting a small-diameter substrate having a central hole with a laser beam from a large-diameter wafer and chamfering the central hole and the outer peripheral edge portion. And a rotary disk that is indexed and rotated by a third motor, at least a pair of first suction bases mounted on the same circumference on the rotary disk, and a first motor for driving the same. A second suction table mounted on the first suction table and a second motor for driving the second suction table, and a laser beam supply for projecting a laser beam to the center hole and the peripheral edge of the substrate to be cut out. An apparatus, a chamfering grindstone and a chamfering grindstone driving mechanism section that are detachably engaged with the center hole and the outer peripheral edge of the cut substrate, a robot for loading and unloading the wafer and the substrate, the motors, the laser Light supply equipment , A drive mechanism unit, a controller for driving and controlling a robot, and the like, the second suction table is arranged to suck the center of the wafer, and the first suction table is arranged at a wafer cutting position. The rotating shaft of the first motor constitutes a substrate cutting and chamfering device which is arranged so as to coincide with the center of the central hole at the cutting position.

[0012]

A large-diameter wafer formed by slicing a single crystal silicon rod is centrally supported on a second suction table by a robot or the like. The cutting position is indexed and the first
The cutting position of the wafer is sucked by the suction table. By releasing the suction of the second suction table and driving the first motor, the wafer is rotated around the cutting position. On the other hand, since the laser beam is projected from the laser beam supply device to the center hole and the outer edge of the small-diameter substrate, the center hole and the outer periphery of the substrate are separated from the wafer by the rotation of the wafer to form the substrate. It Next, the wafer is separated from the substrate by a robot or the like, and the third motor is driven while the substrate is sucked onto the first suction table, and the turntable is rotated by 180 °, for example. As a result, one of the pair of first suction bases engages with the chamfering grindstone side, and the other one indexes to the wafer side for positioning. The chamfering grindstone driving mechanism is operated to simultaneously chamfer the central hole and the peripheral edge of the substrate. On the other hand, by the robot or the like, the wafer from which the substrate is cut is again sucked onto the second suction table, the cutting position is determined, and the wafer is sucked onto the first suction table.
The next substrate is cut out as described above. On the other hand, the chamfered substrate is removed from the first suction table side by a robot or the like and is transported to the next process side.

[0013]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings. FIG. 1 is an explanatory view for explaining all manufacturing steps of this embodiment, FIG. 2 is a configuration view showing an embodiment of the apparatus of the present invention, and FIG. 3 shows a schematic configuration of a chamfering grindstone mechanism portion. FIG. 4 is a configuration diagram, and FIG. 4 is a flowchart for explaining cutting and chamfering processing by the apparatus of this embodiment,
5 and 6 are explanatory views mainly for explaining the chamfering operation.

First, the entire manufacturing process of this embodiment will be described with reference to FIG. Large diameter single crystal silicon rod (diameter d ₂ ) 20
And the wafer 12 is formed. This wafer is lapped using abrasive grains to adjust its thickness and surface. Next, the substrate 14 having a small diameter is cut out by a cutting and chamfering device described later.
In this embodiment, four substrates 14 are cut out from one wafer 12 as shown. The substrate 14, which is cut comprising a thin disc having an outer periphery of the central hole 18 and therewith concentric diameter d ₁ is moved in the chamfering grindstone side of the cut-out chamfering apparatus, the edge of the center hole 18 and the outer periphery 19 Chamfering is performed. Next, polishing finish processing is performed on the front and back surfaces to remove the polishing agent and the like adhering by cleaning, and the manufacture of the desired substrate 14 is completed.

Next, the cut-out chamfering device 1 for carrying out the manufacturing process shown in FIG. 1 will be described with reference to FIG. This device 1 is roughly classified into a rotating disk 2 and a third motor 3 for driving the rotating disk 2.
And a pair of first suction bases 4 and 4 mounted on the turntable 2.
And a first motor 5 for driving the same and a first suction table 4
The second suction table 6 placed on top and the second for driving the same.
Motor 7, laser light supply device 8, chamfering grindstone 9,
10, a chamfering grindstone drive mechanism 11 for driving the same, a robot 13 for loading / unloading the wafer 12, a robot 15 for loading / unloading the chamfered substrate 14, the first and second suction bases 4, A vacuum source 16 connected to 6;
The first to third motors 5, 7, and 3, the laser beam supply device 8, the chamfering grindstone drive mechanism unit 11, the robots 13 and 15, and the control device 17 for controlling the operation of the vacuum source 16 and the like.

A large-diameter rotary disk 2 is pivotally supported on the stationary side of the apparatus and is indexed and rotated by a third motor 3.

In this embodiment, the first suction table 4 is composed of two sets, and they are arranged on the same circumference 180 ° apart from each other. The first suction table 4 is rotatably supported by the bearing 21 on the turntable 2 and is rotationally driven by the first motor 5. A suction port 22 and a vacuum passage 23 are provided inside the first suction table 4 and communicate with the vacuum source 16. Second motor 7
Is placed on the flange 24 of the first suction table 4 and drives the second suction table 6 to rotate. The second suction table 6 has a suction port 2
5 and a vacuum passage 26 are provided inside and communicate with the vacuum source 16. The wafer 12 is mounted on the first and second suction bases 4 and 6 and sucked by the suction ports 22 and 25, respectively. The first suction table 4 is arranged so that the suction port 22 is substantially aligned with the cutout position of the wafer 12 while the center of the wafer 12 is suction-supported by the second suction table 6.

In the present embodiment, the laser beam supplying device 8 includes a laser oscillator 27, a half mirror 28 and a reflecting mirror 2.
It is composed of 9 etc. The laser oscillator 27 is a known one. The laser light 30 from the laser oscillator 27 is reflected by the half mirror 28 and cut out from the outer circumference 19 of the substrate 14.
Is projected on the edge of. Further, the laser light 30 passing through the half mirror 28 is reflected by the reflection mirror 29, and the central hole 18
It is arranged to project light on the edge of the. The center hole 18
And the rotation axis of the first motor 5 coincide with each other.

Next, referring to FIGS. 1 and 3, the chamfering grindstones 9 and 10 for chamfering the edge 31 of the central hole 18 and the edge 32 of the outer circumference 19 of the substrate 14 and the chamfering grindstone drive mechanism section 1 are described.
The general structure of No. 1 will be described. The chamfering grindstones 9 and 10 are arranged so as to engage with the outer periphery 19 and the central hole 18 of the substrate 14 suction-held on the first suction table 4 indexed and positioned on the cutting side and the reflection side. As shown in FIG. 3, the chamfering grindstones 9 and 10 are moved by the grindstone driving mechanism portions 33 and 34,
The substrate 14 is movably supported in the arrow AA direction and the plane direction BB direction orthogonal to the plane of the substrate 14, and the movement position thereof is controlled by the controller 35. As a result, the chamfering grindstones 9 and 10 are cut in the center hole 18 of the substrate 14 cut out.
The chamfering grindstones 9 and 10 can be accurately moved to the reference positions of the inner circumference and the outer circumference 19 and moved by a predetermined cut amount. Further, the chamfering grindstones 9 and 10 are engaged with the dressers 36 and 37, and the dresser drive portion 38,
The dresser 36 and 37 are drive-controlled by 39 to perform a predetermined dressing process. As shown in FIG. 3, chamfering wheels 9, 10
Since chamfered inclined surfaces 40 and 41 are formed on the edges, chamfering of the edges 31 and 32 is performed by bringing the grindstones 9 and 10 into contact with the outer circumference 19 and the center hole 18.

The robot 13 in FIG.
The wafer 12 is moved in the vertical direction in FIG. Further, the robot 15 removes the chamfered substrate 14 from the first suction table 4 and moves it to the next process side.

Next, the cutting and chamfering operation of the apparatus of this embodiment shown in FIG. 2 and the control operation by the control apparatus will be described with reference to the flow chart of FIG. 4 and FIGS. The center point of the wafer 12 is substantially aligned with the suction port 25 of the second suction table 6 and is sucked by the second suction table 6 (step 100). The second motor 7 is driven to index and rotate the wafer 12 to position the cutting position so as to match the first suction table 4 (step 101), and the center of the cutting position is sucked by the first suction table 4. (Step 102). The suction of the second suction table 6 is released, and the inner circumference and the outer circumference 19 of the center hole 18 of the substrate 14 to be cut out.
The projection position of the laser beam 30 is adjusted to the position corresponding to (step 103). The first motor is driven to rotate the wafer 12 around the center of the center hole 18 at the cutting position, and the substrate 14 is cut (step 104). Next, as shown in FIG. 5, the robot 12 holds the wafer 12 having the substrate 14 cut out (step 105).
In this case, the cut-out substrate 14 remains adsorbed on the first adsorption table 4. Next, the third motor 3 is driven to rotate the turntable 2 by 180 °, and as shown in FIG.
Chamfering grindstones 9 and 10
The substrate 14 is pivoted to the side to position the substrate 14 at a position where it engages the chamfering grindstones 9 and 10 (step 106). The chamfering grindstone drive mechanism 11 is operated to move the chamfering grindstones 9 and 10 to the outer circumference 19
Then, the suction holes 18 are brought into contact with each other, and chamfering of the edges 32 and 31 is performed (step 107). In this case, since the substrate 14 is still adsorbed on the first adsorption table 4, the chamfering is performed by controlling the movement of only the grindstones 9 and 10. Therefore, the chamfering grindstone drive mechanism 11 controls the chamfering grindstone with high accuracy to perform the chamfering with high accuracy. At the same time when the substrate 14 is chamfered, as shown in FIG.
Wafer 1 which was grasped by robot 13 as shown in
2 is adsorbed on the second adsorption table 6, the next cutting position of the wafer 12 is indexed, and is adsorbed by the first adsorption table 4 (step 108). The substrate 14 chamfered by the chamfering grindstones 9 and 10 is taken out by the robot 15 and moved to the next process side as shown in FIG. 5 (step 109). In this state, the third motor 3 is driven to rotate the turntable 2 by 180 ° and the same process is performed again (step 1).
10). Thereafter, by repeating the same operation, four substrates 14 can be cut out from one wafer 12, chamfered, and sent to the next process side.

In the above embodiment, the case where four substrates 14 are cut out from the wafer 12 has been described, but the present invention is not limited to this. Further, the structure of the chamfering grindstones 9 and 10 and the structure and operation of the chamfering grindstone driving mechanism 11 are not limited to those in this embodiment. Also, suction means may be used instead of the robots 13 and 15. Further, although the pair of first suction bases 4 and 4 is adopted in this embodiment, a plurality of the first suction bases 4 and 4 may be used. When the cutting of the substrate 14 from one wafer 12 is completed, a new wafer 12 is carried in by the robot 13 or the like and the same operation is performed.
Further, in the present embodiment, the illustrated device is adopted as the laser beam supply device, but it is not limited to that. For example, a plurality of flexible optical fibers for the laser oscillator (two in this embodiment)
Of course, a connected optical fiber transmission module or the like may be used. This makes it possible to more easily and reliably position the projection position of the laser light.

[0023]

According to the present invention, the following remarkable effects are obtained. (1) Since the central hole and the outer periphery of the substrate are simultaneously cut out on the concentric circles by the laser light, the substrate having a high degree of concentricity can be formed. (2) Since the substrate is moved to the chamfering grindstone side while being cut out, and the chamfering grindstone chamfers the central hole and the peripheral edge portion, chamfering with high precision is performed. Therefore, eccentricity between the center hole and the outer periphery hardly occurs. (3) Since the next substrate is cut out during the chamfering process and the cut substrate is configured to be rotationally positioned on the chamfering grindstone side by the rotation of the turntable, there is no waste between steps, Transfer time can be shortened and productivity can be improved. (4) Automatic operation of all processes is possible, and production efficiency can be improved.

[Brief description of drawings]

FIG. 1 is an explanatory diagram for explaining an outline of all steps of a manufacturing method according to an embodiment of the present invention.

FIG. 2 is a configuration diagram showing an embodiment of an apparatus for carrying out the manufacturing method of the present invention.

FIG. 3 is a schematic configuration diagram of a chamfering portion of the cut-out chamfering device.

FIG. 4 is a flowchart for explaining the cutting and chamfering of the substrate by the apparatus of FIG.

FIG. 5 is an explanatory diagram for explaining cutting and chamfering of a substrate.

FIG. 6 is an explanatory diagram for explaining cutting and chamfering of a substrate.

FIG. 7 is an explanatory diagram for explaining an example of a method of manufacturing a substrate.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Cut-out chamfering device 2 Rotating disk 3 Third motor 4 First suction table 5 First motor 6 Second suction table 7 Second motor 8 Laser light supply device 9 Chamfering grindstone 10 Chamfering grindstone 11 Chamfering grindstone drive mechanism Part 12 Wafer 13 Robot 14 Substrate 15 Robot 16 Vacuum source 17 Control device 18 Center hole 19 Outer periphery 20 Single crystal silicon rod 21 Bearing 22 Adsorption port 23 Vacuum passage 24 Flange 25 Adsorption port 26 Vacuum passage 27 Laser oscillator 28 Half mirror 29 Reflection mirror 30 laser light 31 edge part 32 edge part 33 grindstone drive mechanism part 34 grindstone drive mechanism part 35 control part 36 dresser 37 dresser 38 dresser drive part 39 dresser drive part 40 inclined surface 41 inclined surface

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Hideo Kaneko 3-2-1 Sakado, Takatsu-ku, Kawasaki City, Kanagawa Prefecture Corporate Research Center, Shinetsu Chemical Industry Co., Ltd. Address: Nagano Electronics Co., Ltd. (72) Inventor, Toyofumi Aoki 1393, Yashiro, Kojiro, Nagano Prefecture, Nagano Electronics Co., Ltd. In the company

Claims (4)

[Claims] 1. A method for cutting out a small-diameter substrate having a central hole from a large-diameter wafer and chamfering the central hole and the peripheral edge portion, wherein the wafer is adsorbed at the cutting position, Around the center of the substrate cut out from, while the wafer is rotated, the irradiation point of the laser light is positioned at the edge of the central hole of the substrate and its outer periphery, and after cutting the donut-shaped substrate, the substrate Is moved to the chamfering position while adsorbing, to chamfer the center hole and the outer peripheral edge,
A method of slicing and chamfering a substrate, characterized in that a wafer from which a substrate has been cut out at the same time or a new wafer is positioned at a position where the substrate is cut out and cut out with a laser beam. 2. A device for cutting a small-diameter substrate having a central hole with a laser beam from a large-diameter wafer, and chamfering the central hole and the outer peripheral edge portion by a third motor. A rotating disc to be rotated and at least a pair of first discs mounted on the same circumference on the disc.
And a first motor for driving the suction table, and the first
A second suction table placed on the suction table and a second motor for driving the second suction table, and a laser beam supply device for projecting a laser beam to the center hole and the peripheral edge of the substrate to be cut out,
A chamfering grindstone and a chamfering grindstone drive mechanism section that are detachably engaged with the center hole and the outer peripheral edge of the cut substrate, and a robot for loading and unloading the wafer and the substrate,
A control device for driving and controlling the motors, the laser light supply device, the drive mechanism unit, the robot, and the like is provided, and the second suction table is arranged to suck the center of the wafer.
The suction table is arranged at a wafer cutting position, and the rotation shaft of the first motor is arranged at the center of the central hole at the cutting position. 3. The apparatus for manufacturing a magnetic recording medium according to claim 2, wherein the laser beam supply device includes a laser oscillator and a mirror for positioning the laser beam at the irradiation point. 4. The apparatus for manufacturing a magnetic recording medium according to claim 2, wherein the laser light supply device comprises a laser oscillator and a plurality of optical fiber transmission modules connected thereto.