US20110070807A1

US20110070807A1 - Machining apparatus using rotary grinder

Info

Publication number: US20110070807A1
Application number: US12/870,345
Authority: US
Inventors: Masaaki Sudo
Original assignee: Toshiba Corp
Current assignee: Toshiba Corp
Priority date: 2009-09-24
Filing date: 2010-08-27
Publication date: 2011-03-24
Also published as: JP2011067876A

Abstract

According to one embodiment, a machining apparatus includes a disk-like grinder, and a nozzle for discharging a cutting fluid toward the grinder. The grinder cuts or grooves a workpiece by rotating. The grinder is provided with a cutting portion at a periphery of the grinder. The nozzle is provided to face the cutting portion in a radial direction of the grinder and arranged adjustably in a width direction of the cutting portion. The nozzle has a rectangular or elliptic cross-section shape in which a dimension in a width direction of the grinder is larger than a dimension in a peripheral direction of the grinder.

Description

CROSS-REFERENCE TO RELATED ART

This application is based upon and claims the benefit of priority from Japanese Patent Application No. 2009-218427, filed on Sep. 24, 2009; the entire contents of which are incorporated herein by reference.

FIELD

The present embodiment relates to a machining apparatus for cutting or grooving a workpiece by pressing a rotary grinder on the workpiece such as a semiconductor wafer.

BACKGROUND

A machining apparatus for cutting or grooving a workpiece by pressing a rotary grinder, which rotates with a high speed, on the workpiece such as a semiconductor wafer described in Patent Publication 1 (U.S. Pat. No. 7,101,256) has been known.
The grinder in the machining apparatus described in Patent Publication 1 is a machine tool to cut the workpiece such as a semiconductor wafer, in which a width dimension of the grinder is configured to be small, having a size approximately between 10 μm to 100 μm.
With respect to the grinder in process, it is required to supply a cutting fluid in order to cool the grinder or remove working dust. Moreover, it is required to discharge the cutting fluid with high pressure in order to certainly supply the cutting fluid to a contacting portion between the grinder and the workpiece.
Therefore, the cutting fluid is supplied by use of a round nozzle having a small diameter, such as a diameter of approximately 1 mm.
The nozzle is arranged adjustably to face the cutting portion of the grinder. In order to improve machining accuracy, the nozzle is adjusted to position so that a center of the nozzle and a center of the grinder in a width direction face each other in the same plane.
The relationship between the position adjustment of the nozzle and the improvement of the machining accuracy is as follows. Fluid pressure of the cutting fluid discharged from the nozzle is the highest in the center of the nozzle, and gradually lowered outward from the center of the nozzle. Therefore, when the center of the nozzle is shifted from the center of the grinder in the width direction, the fluid pressure of the cutting fluid discharged toward the grinder differs on both sides of the grinder in the width direction, the grinder is distorted due to the fluid pressure difference acting on the both sides of the grinder in the width direction, and the machining accuracy is lowered because the grinder is rotated while being distorted.
As described in Patent Publication 1, a position adjustment mechanism with high accuracy is required in order to adjust the position of the nozzle so that the center of the nozzle and the center of the grinder in the width direction face each other on the same plane. As a result, the cost for the machining apparatus has been high.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic view illustrating a whole constitution of a first embodiment.

FIG. 2 is a perspective view illustrating a part of the first embodiment.

FIG. 3 is a perspective view illustrating a part of a second embodiment.

FIG. 4 is a partially sectional perspective view of a nozzle according to a third embodiment.

FIG. 5 is a partially sectional perspective view of a nozzle according to a fourth embodiment.

FIG. 6 is a partially sectional perspective view of a nozzle according to a fifth embodiment.

FIG. 7 is a partially sectional perspective view of a nozzle according to a sixth embodiment.

DETAILED DESCRIPTION

In general, according to one embodiment, a machining apparatus includes a disk-like grinder, and a nozzle for discharging a cutting fluid to the grinder. The grinder cuts or grooves a workpiece by rotating. The grinder is provided with a cutting portion at a periphery of the grinder. The nozzle faces the cutting portion in a radial direction of the grinder, and is arranged adjustably in a width direction of the cutting portion. A cross-section shape of the nozzle has a rectangular shape or an elliptic shape in which a dimension in a width direction of the cutting portion is larger than a dimension in a peripheral direction of the cutting portion.
Hereinafter, embodiments will be described with reference to the drawings.

(First Embodiment)

A first embodiment will be described with reference to FIGS. 1 and 2. A machining apparatus according to the first embodiment is a dicing apparatus for cutting or grooving a workpiece W such as a semiconductor wafer, and includes a thin disk-like grinder 1. The grinder 1 is held between two flanges 2. A rotating shaft 4 of an actuator 3 is approximately horizontally connected to a center of each flange 2 in a radial direction.
A periphery of the grinder 1 is provided with a cutting portion 5 that performs cutting and grooving while intervening the workpiece W. The cutting portion 5 is formed to have a width dimension of 10 to 100 μm in a thickness direction of the cutting portion 5.
A chuck table 6 is provided underneath to the grinder 1 connected to the rotating shaft 4. The chuck table 6 detachably hold the workpiece W by applying a vacuum force or by using a wax.
A nozzle 7 is arranged facing the cutting portion 5 in a radial direction of the grinder 1. The nozzle 7 discharges a cutting fluid L toward an intervening portion between the cutting portion 5 and the workpiece W. The nozzle 7 is held by a holding member 8 being movable in an X direction, a Y direction, and a Z direction, and pivotable in a θ direction. The holding member 8 is driven by an actuator 9. The nozzle 7 is appropriately adjusted in the X direction, the Y direction, the Z direction, and the θ direction by driving the holding member 8 by the actuator 9.
The actuator 9 may be a screw feeding mechanism, a gear drive mechanism, a piezoelectric actuator, and the like. The X direction as one of the moving directions of the nozzle 7 is a width direction of the grinder 1. As for the cutting fluid L, pure water or a fluid in which a rust inhibitor is added to pure water is adopted.
The holding member 8 is attached with a light source 10 to direct light toward the grinder 1. The light source 10 is positioned so that a center of a cross-section of light corresponds to a center of the grinder 1 in the width direction in the cutting fluid L discharged from the nozzle 7. As for the light source 10, a semiconductor laser and the like is adopted.
A light sensor 11 is arranged to face the light source 10 on an opposite side of the grinder 1, as a detector to detect light emitted from the light source 10. The light sensor 11 detects an intensity distribution of the light emitted from the light source 10 and outputs the detected intensity distribution to a controller 12.
The light emitted from the light source 10 is blocked by the grinder 1, or diffusely reflected by the cutting fluid L. Therefore, the intensity distribution of the light that reaches the opposite side of the grinder 1 changes according to a position and angle of the nozzle 7, i.e. the position and angle of the light source 10. That is, the position and angle of the nozzle 7 can be expected by detecting the intensity distribution of the light emitted from the light source 10 by the light sensor 11.
The controller 12 controls the actuator 9 based on both the intensity distribution of the light output from the light sensor 11 and an optimum intensity distribution preliminarily stored in a memory device 13, so as to move the nozzle 7 to an optimum position.
The above-mentioned “optimum position of the nozzle 7” is the position where the nozzle 7 discharges the cutting fluid so as to machine the workpiece W optimally. In addition, the “optimum intensity distribution” is the light intensity distribution detected by the light sensor 11 when the nozzle 7 is positioned at the optimum position. Namely, when the light sensor 11 detects the optimum intensity distribution, the nozzle 7 can be presumed to be positioned at the optimum position.
The memory device 13 stores the optimum position of the nozzle 7 as coordinate data (X, Y, Z, θ). The coordinate data is stored in the memory device 13 by inputting the data through an external terminal 14.
The cross-section of the nozzle 7 when the nozzle 7 is cut in a plane parallel to an opening 7 a of the nozzle 7 is formed to have a rectangular shape in which a dimension “a” in the width direction of the grinder 1 (in the X direction) is larger than a dimension “b” in the peripheral direction of the grinder 1 (in the Z direction) perpendicular to the X direction. Therefore, when the cutting fluid L is discharged from the nozzle 7 toward the intervening portion between the cutting portion 5 and the workpiece W, the cutting fluid L is discharged widely in the width direction of the grinder 1.
In such a configuration, when the workpiece W is cut or grooved by use of the machining apparatus, the workpiece W is held on the chuck table 6, the grinder 1 is rotated together with the rotating shaft 4 of the actuator 3, and the grinder 1 is moved so as to bring the rotating cutting portion 5 to the workpiece W. Then, the cutting fluid L is discharged from the nozzle 7, and the intensity distribution of light emitted from the light source 10 is detected by the light sensor 11.
The light intensity distribution detected by the light sensor 11 is output to the controller 12, and compared to the light intensity distribution stored in the memory device 13. Based on the comparison result, the controller 12 outputs a drive signal to the actuator 9 so as to conform the light intensity distribution detected by the light sensor 11 to the light intensity distribution stored in the memory device 13. Accordingly, the nozzle 7 is adjusted to be positioned at the optimum position, and the cutting fluid L discharged from the nozzle 7 is supplied optimally for machining.
After the nozzle 7 is positioned at the optimum position, the grinder 1 is further moved downward to start cutting or grooving the workpiece W.
The machining apparatus according to the first embodiment is operated such that the nozzle 7 is automatically positioned at the optimum position by detecting light emitted from the light source 10 by the light sensor 11 and driving the actuator 9 based on the detected result.
Thus, the nozzle 7 can be accurately and repeatably positioned at the optimum position. Also, cutting or grooving of the workpiece W can be carried out with almost the same precision regardless of skill levels of operators who operate the machining apparatus. As a result, chipping or cracking is reduced, and a uniformity of a machining surface quality can be achieved.
In addition, the cross-section of the nozzle 7 is formed to have a rectangular shape in which the dimension “a” in the width direction of the grinder 1 (in the X direction) is larger than the dimension “b” in the peripheral direction of the grinder 1 (in the Z direction) perpendicular to the X direction. Accordingly, a range in which fluid pressure of the cutting fluid L discharged from the nozzle 7 is the highest becomes wide in the width direction of the grinder 1.
Thus, even if the nozzle 7 is roughly positioned, the cutting fluid L with the highest fluid pressure to be discharged from the nozzle 7 can be easily positioned at the center position in the width direction of the grinder 1. Therefore, even if the nozzle 7 is roughly positioned, the fluid pressure of the cutting fluid L discharged from the nozzle 7 can become equal on both sides of the cutting fluid L in the width direction of the grinder 1. As a result, the fluid pressure of the cutting fluid L acting on the both sides of the grinder 1 in the width direction is prevented from being different from each other caused by the rough positioning of the nozzle 7. Moreover, the grinder 1 can be prevented from being distorted and rotating while being distorted due to such a fluid pressure difference. Accordingly, the machining apparatus can be maintained with high machining accuracy. Consequently, the actuator 9 may have a lowered positioning function in performance, which results in achievement of low cost of the machining apparatus.
The first embodiment was described above explaining the example of the case where the cross-section of the nozzle 7 has a rectangular shape. However, the rectangular shape is not limited to a quadrilateral shape with four right angles.
The rectangular shape may be a trapezoidal shape as long as the dimension “a” in the width direction of the grinder 1 is larger than the dimension “b” in the peripheral direction of the grinder 1.

(Second Embodiment)

A second embodiment will be described with reference to FIG. 3. Note that, in the second embodiment and the other embodiments described below, the same constituent elements as the constituent elements of the aforementioned embodiments are indicated by the same reference numerals, and explanations thereof will not be repeated.
The fundamental constitution of the second embodiment is the same as the first embodiment illustrated in FIGS. 1 and 2. Meanwhile, the second embodiment includes a nozzle 7A having a different shape from the nozzle of the first embodiment.
The cross-section of the nozzle 7A when the nozzle 7A is cut in a plane parallel to the opening 7 a of the nozzle 7A is formed to have an elliptic shape in which the dimension “a” in the width direction of the grinder 1 (in the X direction) is larger than the dimension “b” in the peripheral direction of the grinder 1 (in the Z direction) perpendicular to the X direction. Therefore, when the cutting fluid L is discharged from the nozzle 7A toward the intervening portion between the cutting portion 5 of the grinder 1 and the workpiece W, the cutting fluid L is discharged widely in the width direction of the grinder 1.
In such a configuration, since the cross-section of the nozzle 7A is formed to have an elliptic shape in which the dimension “a” in the width direction of the grinder 1 (in the X direction) is larger than the dimension “b” in the peripheral direction of the grinder 1 perpendicular to the X direction (in the Z direction), a range in which fluid pressure of the cutting fluid L discharged from the nozzle 7A is the highest becomes wide in the width direction of the grinder 1.
Thus, even if the nozzle 7A is roughly positioned, the cutting fluid L with the highest fluid pressure to be discharged from the nozzle 7A can be easily positioned at the center position in the width direction of the grinder 1. Therefore, even if the nozzle 7A is roughly positioned, the fluid pressure of the cutting fluid L discharged from the nozzle 7A can become equal on both sides of the cutting fluid L in the width direction of the grinder 1. As a result, the fluid pressure of the cutting fluid L acting on the both sides of the grinder 1 in the width direction is prevented from being different from each other caused by the rough positioning of the nozzle 7A. Moreover, the grinder 1 can be prevented from being distorted and rotating while being distorted due to such a fluid pressure difference. Accordingly, the machining apparatus can be maintained with high machining accuracy. Consequently, the actuator 9 may have a lowered positioning function in performance, which results in achievement of low cost of the machining apparatus.

(Third Embodiment)

A third embodiment will be described with reference to FIG. 4. The fundamental constitution of the third embodiment is the same as the first embodiment illustrated in FIGS. 1 and 2. Meanwhile, the third embodiment includes a nozzle 7B having a different inside shape from the nozzle in the first embodiment.
A peripheral shape of the nozzle 7B is formed to have a rectangular shape similarly to the nozzle 7 in the first embodiment. The nozzle 7B in the third embodiment is provided inside with a plurality of flow-straightening plates 15 along a longitudinal direction (the X direction) of a cross-section of the nozzle 7B. The flow-straightening plates 15 are arranged that the flow-straightening plates 15 straighten flow of the cutting fluid L discharged from the opening 7 a of the nozzle 7B in the width direction of the grinder 1 that is the longitudinal direction of the opening 7 a.
In such a configuration, the cutting fluid L discharged from the opening 7 a of the nozzle 7B toward the grinder 1 is straightened by the flow-straightening plates 15, so that a disturbed flow when the cutting fluid L is discharged from the opening 7 a of the nozzle 7B is prevented. Therefore, the fluid pressure of the cutting fluid L acting on the both sides of the grinder 1 in the width direction can be prevented from being different from each other due to the disturbed flow caused when the cutting fluid L is discharged from the opening 7 a of the nozzle 7B. Accordingly, the occurrence of the fluid pressure difference of the cutting fluid L on the both sides of the grinder 1 in the width direction caused by the disturbed flow of the cutting fluid L discharged from the nozzle 7B can be prevented. Moreover, the grinder 1 can be prevented from being distorted and rotating while being distorted due to such a fluid pressure difference of the cutting fluid L. As a result, high machining accuracy in the machining apparatus can be achieved.

(Fourth Embodiment)

A fourth embodiment will be described with reference to FIG. 5. The fundamental constitution of the fourth embodiment is the same as the third embodiment illustrated in FIG. 4. Meanwhile, the fourth embodiment includes a nozzle 7C having a different peripheral shape from the nozzle in the third embodiment.
The peripheral shape of the nozzle 7C is formed to have an elliptic shape similarly to the nozzle 7A in the second embodiment. The nozzle 7C in the fourth embodiment having the elliptic peripheral shape is provided inside with a plurality of flow-straightening plates 15 in a longitudinal direction (the X direction) of a cross-section of the nozzle 7C. The flow-straightening plates 15 are arranged that the flow-straightening plates 15 straighten flow of the cutting fluid L discharged from the opening 7 a of the nozzle 7C in the width direction of the grinder 1 that is the longitudinal direction of the opening 7 a.
In such a configuration, the cutting fluid L discharged from the opening 7 a of the nozzle 7C toward the grinder 1 is straightened by the flow-straightening plates 15, so that a disturbed flow when the cutting fluid L is discharged from the opening 7 a of the nozzle 7C is prevented. Therefore, the fluid pressure of the cutting fluid L acting on the both sides of the grinder 1 in the width direction can be prevented from being different from each other due to the disturbed flow caused when the cutting fluid L is discharged from the opening 7 a of the nozzle 7C. Accordingly, the occurrence of the fluid pressure difference of the cutting fluid L on the both sides of the grinder 1 in the width direction caused by the disturbed flow of the cutting fluid L discharged from the nozzle 7C can be prevented. Moreover, the grinder 1 can be prevented from being distorted and rotating while being distorted due to such a fluid pressure difference of the cutting fluid L. As a result, high machining accuracy in the machining apparatus can be achieved.

(Fifth Embodiment)

A fifth embodiment will be described with reference to FIG. 6. The fundamental constitution of the fifth embodiment is the same as the third embodiment illustrated in FIG. 4. Meanwhile, the fifth embodiment includes a nozzle 7D, which is different from the third embodiment, and is provided with disturbed flow restrainers 16 formed in a streamlined shape in a flowing direction of the cutting fluid L at end portions of the flow-straightening plates 15 in the opening 7 a of the nozzle 7D.
In such a configuration, by providing the disturbed flow restrainers 16 at the end portions of the flow-straightening plates 15, the occurrence of the disturbed flow when the cutting fluid L is discharged from the opening 7 a of the nozzle 7D can be further prevented. Accordingly, the fluid pressure difference of the cutting fluid L on the both sides of the grinder 1 in the width direction caused by the disturbed flow can be prevented. Moreover, the grinder 1 can be prevented from being distorted and rotating while being distorted due to such a fluid pressure difference of the cutting fluid L. As a result, high machining accuracy in the machining apparatus can be achieved.

(Sixth Embodiment)

A sixth embodiment will be described with reference to FIG. 7. The fundamental constitution of the sixth embodiment is the same as the fifth embodiment illustrated in FIG. 6. Meanwhile, the sixth embodiment includes a nozzle 7E having a different peripheral shape from the nozzle in the fifth embodiment.
The peripheral shape of the nozzle 7E is formed to have an elliptic shape similarly to the nozzle 7A in the second embodiment. The nozzle 7E in the sixth embodiment having the elliptic peripheral shape is provided inside with the flow-straightening plates 15 in a longitudinal direction (the X direction) of a cross-section of the nozzle 7E. The nozzle 7D is provided with the disturbed flow restrainers 16 formed in a streamlined shape in a flowing direction of the cutting fluid L at the end portions of the flow-straightening plates 15 in the opening 7 a of the nozzle 7E.
In such a configuration, by providing the disturbed flow restrainers 16 at the end portions of the flow-straightening plates 15, the occurrence of the disturbed flow when the cutting fluid L is discharged from the opening 7 a of the nozzle 7E can be further prevented. Accordingly, the fluid pressure difference of the cutting fluid
L on the both sides of the grinder 1 in the width direction caused by the disturbed flow can be prevented. Moreover, the grinder 1 can be prevented from being distorted and rotating while being distorted due to such a fluid pressure difference of the cutting fluid L. As a result, high machining accuracy in the machining apparatus can be achieved.
While certain embodiments have been described, these embodiments have been presented by way of example only, and are not intended to limit the scope of the inventions. Indeed, the novel methods and systems described herein may be embodied in a variety of other forms; furthermore, various omissions, substitutions and changes in the form of the methods and systems described herein may be made without departing from the spirit of the inventions. The accompanying claims and their equivalents are intended to cover such forms or modifications as would fall within the scope and spirit of the inventions.

Claims

1. A machining apparatus, comprising:

a grinder that is formed in a disk-like shape and cuts or grooves a workpiece by rotating, the grinder provided with a cutting portion at a periphery thereof; and

a nozzle that is provided to face the cutting portion in a radial direction of the grinder and arranged adjustably in a width direction of the cutting portion, and discharges cutting fluid toward the grinder, the nozzle having a rectangular cross-section shape in which a dimension in a width direction of the grinder is larger than a dimension in a peripheral direction of the grinder.

2. A machining apparatus, comprising:

a grinder that is formed in a disk-like shape and cuts or grooves a workpiece by rotating, the grinder being provided with a cutting portion at a periphery thereof and

a nozzle that is provided to face the cutting portion in a radial direction of the grinder and arranged adjustably in a width direction of the cutting portion, and discharges cutting fluid toward the grinder, the nozzle having an elliptic cross-section shape in which a dimension in a width direction of the grinder is larger than a dimension in a peripheral direction of the grinder.

3. The machining apparatus of claim 1, further comprising:

a memory device for storing a position of the nozzle;

a detector for detecting a relative position between the grinder and the nozzle; and

an actuator for moving the nozzle.

4. The machining apparatus of claim 2, further comprising:

a memory device for storing a position of the nozzle;

an actuator for moving the nozzle.

5. The machining apparatus of claim 1, further comprising:

a plurality of flow-straightening plates arranged inside the nozzle in a longitudinal direction of a cross-section of the nozzle, the flow-straightening plates for straightening flow of the cutting fluid discharged from the nozzle.

6. The machining apparatus of claim 2, further comprising:

7. The machining apparatus of claim 3, further comprising:

8. The machining apparatus of claim 4, further comprising:

9. The machining apparatus of claim 5, further comprising:

a disturbed flow restrainer formed in a streamlined shape provided at an end portion of at least one of the flow-straightening plates in an opening of the nozzle in a flowing direction of the cutting fluid, the disturbed flow restrainer for restraining disturbed flow of the cutting fluid discharged from the nozzle.

10. The machining apparatus of claim 6, further comprising:

11. The machining apparatus of claim 7, further comprising:

12. The machining apparatus of claim 8, further comprising: