JP7296849B2 - Cutting device and cutting blade dressing method - Google Patents

Description

The present invention relates to a cutting apparatus for cutting a workpiece such as a semiconductor device wafer with a cutting blade, and a dressing method for the cutting blade.

2. Description of the Related Art Conventionally, as disclosed in Patent Document 1, for example, a technique for cutting a workpiece such as a semiconductor device wafer with a cutting blade is known. The cutting blade includes, for example, a blade (rotary cutting blade) in which abrasive grains such as diamond or cubic boron nitride are bonded with a bonding material containing metal, and a base to which the blade is fixed.

During cutting, cutting fluid is supplied to the blade and the workpiece for the purpose of removing machining waste and cooling the machining point. When the workpiece is a semiconductor device wafer, pure water is widely used as the cutting fluid.

Further, as disclosed in Patent Document 1, idling operation is recommended before machining or during standby. In this idling operation, the spindle that fixes the blade is rotated for a certain period of time to cause the blade to idle, while cutting fluid continues to be sprayed onto the blade. Also, at this time, various movable parts such as a holding table may be operated.

By performing such an idling operation, the influence of thermal strain caused by heat generated during operation of the apparatus can be suppressed, making it possible to stabilize machining accuracy in the Y-axis direction and Z-axis direction.

JP-A-11-114949

However, impurities such as metal ions easily dissolve in pure water, and depending on the spindle speed, amount of water, and type of blade, excessive idling may cause corrosion of the bond and base of the cutting blade. , bond elution occurs, and the cutting blade deteriorates.

In particular, in the manufacturing process of semiconductor device wafers, a cutting fluid in which carbon dioxide is mixed in pure water is sometimes used in order to prevent electrostatic breakdown of devices. In this case, since the cutting fluid becomes acidic, there is a problem that deterioration of the cutting blade progresses more easily.

If the cutting blade is degraded, it may cause abnormal wear or breakage of the cutting blade, resulting in deterioration of machining quality.

In view of the above, the present invention provides a novel technique for preventing the deterioration of cutting blades caused by idling operation, the accompanying abnormalities of cutting blades, and the deterioration of processing quality. .

According to one aspect of the invention,
a cutting unit including a cutting blade having a cutting edge to which abrasive grains are bound by a bonding material containing metal and a spindle to which the cutting blade is attached;
a holding table holding a workpiece to be cut by the cutting blade;
a cutting fluid supply nozzle for supplying cutting fluid to the cutting blade;
a controller that controls at least the cutting unit;
A cutting device comprising a dressed member for dressing the cutting blade,
an idling operation in which the cutting blade is idly rotated while the cutting fluid is supplied to the cutting blade;
A dressing operation for dressing by cutting the cutting blade into the member to be dressed;
is configured to enable
The controller is
Comparing the cumulative time of idling operation with a predetermined upper limit time,
The cutting device performs the dressing operation when the accumulated time exceeds the predetermined upper limit time.

Further, according to one aspect of the present invention,
The upper limit time is set in advance according to at least one of the pH, conductivity, and specific resistance of the cutting fluid.

Further, according to one aspect of the present invention,
further comprising detecting means for detecting at least one characteristic of the cutting fluid, pH, conductivity, and resistivity;
The controller defines the upper limit time based on the characteristics detected by the detection means.

Further, according to one aspect of the present invention,
A cutting unit including a cutting blade having a cutting edge to which abrasive grains are bonded with a bonding material containing metal and a spindle to which the cutting blade is attached, a holding table for holding a workpiece to be cut with the cutting blade; A cutting blade dressing method for dressing the cutting blade of a cutting device comprising a cutting fluid supply nozzle for supplying cutting fluid to the cutting blade,
a step of measuring the time during which idling operation in which the cutting blade is idly rotated while supplying the cutting fluid to the cutting blade is performed to acquire the accumulated time;
comparing the accumulated time to a predetermined upper time limit;
and dressing the cutting blade when the cumulative time exceeds the upper limit time.

Further, according to one aspect of the present invention,
The step of presetting the upper limit time according to at least one of the pH, conductivity, and specific resistance of the cutting fluid is further included.

Further, according to one aspect of the present invention,
detecting at least one characteristic of cutting fluid pH, conductivity, resistivity;
setting the upper time limit based on the detected characteristic.

According to the configuration of the present invention, even if deterioration occurs in the cutting blade due to idling operation, the cutting ability of the cutting blade can be recovered by performing the dressing operation when the deterioration is minor. It is possible to prevent the occurrence of defects such as abnormalities in processing and deterioration of processing quality.

1 is a perspective view of a cutting device according to one embodiment of the present invention; FIG. It is a figure explaining dressing work. It is a figure explaining idling driving.

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. FIG. 1 is a perspective view showing a cutting device 2 according to one embodiment of the invention. The cutting device 2 has a base 4 on which a holding table 8 is arranged so as to be able to reciprocate in the X-axis direction by a cutting feed mechanism (X-axis movement mechanism).

The upper surface of the base 4 is provided with a cassette mounting portion 5a for mounting a cassette 5 containing a workpiece (not shown) and a cleaning device 6 for cleaning the workpiece after cutting. The workpiece is transferred from the cassette 5 onto the holding table 8 by a transfer device (not shown), cut by the cutting unit 34, transferred to the cleaning device 6 and cleaned, and transferred to the cassette 5 after cleaning. carried out.

A plurality of clamps 9 and a water cover 11 are arranged around the holding table 8, and a bellows 12 is connected across the water cover 11 and the base 4 to protect the shaft of the cutting feed mechanism.

A dress board table 52 is provided on the upper surface of the water cover 11 to expose and hold the upper surface of the dress board 50 . The water cover 11 moves in the X-axis direction together with the holding table 8. As the water cover 11 moves, the dressing board table 52 also moves in the X-axis direction.

A gate-shaped column 14 is erected on the base 4, and a pair of guide rails 15 extending in the Y-axis direction and a Y-axis moving mechanism 17 comprising a ball screw 16a and a pulse motor 16b are provided on the side surfaces of the column 14. , and a Y-axis moving block 18 are provided, and when the Y-axis moving mechanism 17 is driven, the Y-axis moving block 18 moves along the guide rail 15 in the Y-axis direction.

The Y-axis moving block 18 is provided with a pair of guide rails 19 extending in the Z-axis direction, a Z-axis moving mechanism 32 comprising a ball screw 31a and a pulse motor 31b, and a Z-axis moving block 30. By driving the mechanism 32, the Z-axis moving block 30 moves along the guide rail 19 in the Z-axis direction.

A cutting unit 34 is attached to the Z-axis movement block 30, a spindle (not shown) is rotatably accommodated in a spindle housing 36 of the cutting unit 34, and a cutting blade 38 is attached to the tip of the spindle. there is A substantially upper half of the cutting blade 38 is covered with a blade cover 40 . An imaging unit 7 is attached to the spindle housing 36 of the cutting unit 34 .

2 and 3 are diagrams for explaining the configuration of the cutting unit 34. FIG. The cutting unit 34 includes a cutting blade 38 and a blade cover 40 , and the cutting edge of the cutting blade 38 protrudes downward from the blade cover 40 . The blade cover 40 has a first cutting fluid supply nozzle 41 that supplies cutting fluid such as pure water to the lower portion of the cutting blade 38, and a second cutting fluid supply nozzle 42 that supplies cutting fluid to the outer peripheral portion of the cutting blade 38. , is provided.

For example, as shown in FIG. 2, the cutting blade 38 is a hub type blade in which a cutting edge 38b is formed on a base (hub base) 38a made of aluminum by electrodeposition, or a hub type blade in which a cutting edge 38b is formed by electrodeposition on a base (hub base) 38a made of aluminum, or a blade having no base but a flange. The present invention can also be suitably applied to fixed cutting blades.

Cutting fluid is supplied from a cutting fluid supply source 44 to the first cutting fluid supply nozzle 41 and the second cutting fluid supply nozzle 42 through a control valve 46, a cutting fluid supply path 48, and branch supply paths 48a and 48b, respectively. be done. The control valve 46 is controlled to be opened/closed by a controller 10 that controls various mechanisms of the cutting device 2 (FIG. 1).

As shown in FIG. 2, a dressing board 50 is positioned below the cutting unit 34 to enable the dressing operation. This dressing operation is performed by rotating the cutting blade 38 at high speed and cutting it to a predetermined depth with respect to the dress board 50 (dress board table 52) that moves in the X-axis direction together with the holding table 8 (FIG. 1). .

The dressing board 50 functions as a member to be dressed for dressing the cutting blade 34. For example, abrasive grains such as white alundum (WA) and green carborundum (GC) are combined with a binding material such as resin or ceramics. It is produced by fixing with

The dressing operation may be performed using the dress board 50 described above, or may be performed using a piece of silicon held by the dress board table, or may be preliminarily cut by cutting an excess portion of the workpiece ( pre-cutting). In this case, the work (workpiece) functions as the member to be dressed.

The dressing operation is performed to prevent the cutting blade 38 from being damaged during cutting when the cutting blade 38 is clogged or blocked or the outer periphery of the cutting blade 38 is unevenly worn. Specifically, by cutting the member to be dressed with the cutting blade 38 , the cutting blade 38 is worn to protrude abrasive grains (self-sharpening), thereby recovering the cutting ability of the cutting blade 38 .

With regard to this dressing operation, in the present invention, taking into account that the cutting blade 38 deteriorates due to the idling operation, the dressing operation of the cutting blade 38 is performed according to the implementation status of the idling operation. The deterioration of the cutting blade 38 due to idling operation is considered to be corrosion of the bond and base due to the cutting fluid, elution of the bond, and the like. are particularly susceptible to deterioration.

FIG. 3 shows idling operation at a distance from the holding table 8 before machining or during standby. During this idling operation, the cutting blade 38 is rotated at high speed, and cutting fluid is jetted toward the cutting blade 38 from the first cutting fluid supply nozzle 41 and the second cutting fluid supply nozzle 42 .

The idling time (time during which the idling operation is performed), that is, the time during which the cutting fluid is jetted while the cutting blade 38 is idle while the cutting blade 38 is not performing cutting is measured and stored by the controller 10. be. In this way, the controller 10 functions as a measuring means for measuring the idling time, and the cumulative time T1 of the idling operation performed for the cutting blade 38 is acquired.

The controller 10 stores in advance an upper limit time T0 allowed as the cumulative time of idling operation, and when the cumulative time T1 exceeds the upper limit time T0, the controller 10 performs the dressing operation as shown in FIG. to implement. In this manner, the controller 10 functions as a dressing control section that performs dressing work.

The upper limit time T0 is set so that the deterioration of the cutting blade 38 remains at a minor stage, thereby preventing problems such as abnormality of the cutting blade and deterioration of processing quality due to progression of deterioration. .

This upper limit time T0 may be defined as a single value, or may be set in correlation with the thickness (μm) of the cutting blade as shown in Table 1 below. Also, the upper limit time T0 or the thickness (μm) of the cutting blade may be correlated with the dressing conditions.

Dressing conditions are conditions for recovering the cutting ability of the cutting blade 38, and include the distance for cutting the dress board (dressing distance (m) or number of cutting lines), the amount of cutting into the dress board, the index size, and the spindle rotation. number, the feed rate of the dressboard table, and so on. In this manner, the controller 10 functions as a correlation information storage unit that stores the correlation information between the upper limit time T0 of the idling operation and the dressing conditions.

Furthermore, the upper limit time T0 may be set in correlation with the characteristics of the cutting fluid. For example, the controller 10 stores correlation information between the parameters of the cutting fluid used for cutting, such as pH, conductivity, and specific resistance value, and the upper limit time T0. The controller 10 selects the upper limit time T0 according to the characteristics of the cutting fluid.

Alternatively, as shown in FIG. 2, the cutting fluid supply path 48 is provided with detection means 45 for detecting each parameter of the cutting fluid pH, conductivity, and specific resistance value, and the detected parameters and the values stored in the controller are The upper limit time T0 may be selected based on the correlation information. According to this, it becomes possible to omit the input of each parameter by the operator and to refer to the measured value of each parameter in real time.

The present invention can be implemented as described above.
That is, as shown in FIGS. 1 to 3,
a cutting unit 34 including a cutting blade 38 having a cutting edge to which abrasive grains are bound by a bond material containing metal and a spindle on which the cutting blade 38 is mounted;
a holding table 8 holding a workpiece to be cut by the cutting blade 38;
Cutting fluid supply nozzles (first cutting fluid supply nozzle 41, second cutting fluid supply nozzle 42) that supply cutting fluid to the cutting blade 38;
a controller 10 that controls at least the cutting unit 34;
A cutting device 2 comprising a dressed member (dressing board 50) for dressing the cutting blade 38,
an idling operation in which the cutting blade 38 is idly rotated while the cutting fluid is supplied to the cutting blade 38;
A dressing operation in which the cutting blade 38 is cut into the member to be dressed and dressed;
is configured to enable
The controller 10
Comparing the cumulative time T1 during which the idling operation is performed with a predetermined upper limit time T0,
The cutting device 2 performs a dressing operation when the cumulative time T1 exceeds a predetermined upper limit time T0.

As a result, even if deterioration occurs in the cutting blade due to idling operation, the cutting ability of the cutting blade can be recovered by performing the dressing operation when the deterioration is minor. It is possible to prevent the occurrence of defects such as deterioration of

Also, the upper limit time T0 is set in advance according to at least one of the pH, conductivity, and specific resistance of the cutting fluid.

Thereby, the upper limit time T0 is set according to the characteristics of the cutting fluid, and the dressing work can be performed at appropriate timing. For example, in a processing environment where deterioration is likely to progress, such as when the pH is low and strongly acidic, the dressing operation is performed at an early stage, and the occurrence of defects can be reliably prevented.

Further, as shown in FIG. 2, a detection means 45 for detecting at least one characteristic of the cutting fluid pH, conductivity, and specific resistance is provided, and the controller 10 detects the characteristics detected by the detection means 45. The upper limit time T0 is defined based on.

As a result, it is possible to acquire the characteristics of the cutting fluid in the actual machining environment and define the upper limit time T0, thereby enabling control with feedback of the actual machining environment.

Also, as shown in FIGS.
A cutting unit 34 including a cutting blade 38 having a cutting edge bonded with abrasive grains by a bonding material containing metal and a spindle to which the cutting blade 38 is attached, and a holding table holding a workpiece to be cut by the cutting blade 38. 8, and a cutting fluid supply nozzle (first cutting fluid supply nozzle 41, second cutting fluid supply nozzle 42) that supplies cutting fluid to the cutting blade 38. A method of dressing a blade 38, comprising:
a step of measuring the time during which an idling operation in which the cutting blade 38 is idly rotated while supplying the cutting fluid to the cutting blade 38 is performed to acquire the cumulative time T1;
comparing the cumulative time T1 with a predetermined upper limit time T0;
and a step of dressing the cutting blade 38 when the cumulative time T1 exceeds the upper limit time T0.

The method further includes the step of presetting the upper limit time T0 in accordance with at least one of the pH, conductivity, and specific resistance of the cutting fluid.

detecting at least one characteristic of cutting fluid pH, conductivity, resistivity;
setting the upper time limit T0 based on the detected characteristic.

With the dressing method described above, the upper limit time T0 is set according to the characteristics of the cutting fluid, and the dressing operation can be performed at appropriate timing. For example, in a processing environment where deterioration is likely to progress, such as when the pH is low and strongly acidic, the dressing operation is performed at an early stage, and the occurrence of defects can be reliably prevented.

2 cutting device 8 holding table 10 controller 11 water cover 12 bellows 34 cutting unit 38 cutting blade 40 blade cover 41 first cutting fluid supply nozzle 42 second cutting fluid supply nozzle 44 cutting fluid supply source 45 detecting means 46 control valve 48 cutting fluid Supply path 50 Dress board 52 Dress board table T0 Upper limit time T1 Cumulative time

Claims (6)

a cutting unit including a cutting blade having a cutting edge to which abrasive grains are bound by a bonding material containing metal and a spindle to which the cutting blade is attached;
a holding table holding a workpiece to be cut by the cutting blade;
a cutting fluid supply nozzle for supplying cutting fluid to the cutting blade;
a controller that controls at least the cutting unit;
A cutting device comprising a dressed member for dressing the cutting blade,
an idling operation in which the cutting blade is idly rotated while the cutting fluid is supplied to the cutting blade;
A dressing operation for dressing by cutting the cutting blade into the member to be dressed;
is configured to enable
The controller is
Comparing the cumulative time of idling operation with a predetermined upper limit time,
A cutting device that performs the dressing operation when the accumulated time exceeds the predetermined upper limit time. The upper limit time is set in advance according to at least one of the cutting fluid's pH, conductivity, and specific resistance.
The cutting device according to claim 1, characterized in that: further comprising detecting means for detecting at least one characteristic of the cutting fluid, pH, conductivity, and resistivity;
The controller defines the upper limit time based on the characteristics detected by the detection means.
The cutting device according to claim 1, characterized in that: A cutting unit including a cutting blade having a cutting edge to which abrasive grains are bonded with a bonding material containing metal and a spindle to which the cutting blade is attached, a holding table for holding a workpiece to be cut with the cutting blade; A cutting blade dressing method for dressing the cutting blade of a cutting device comprising a cutting fluid supply nozzle for supplying cutting fluid to the cutting blade,
a step of measuring the time during which idling operation in which the cutting blade is idly rotated while supplying the cutting fluid to the cutting blade is performed to acquire the accumulated time;
comparing the accumulated time to a predetermined upper time limit;
and C. dressing the cutting blade when the cumulative time exceeds the upper time limit. presetting the upper limit time according to at least one characteristic of cutting fluid pH, conductivity, and resistivity;
The cutting blade dressing method according to claim 4, characterized in that: detecting at least one characteristic of cutting fluid pH, conductivity, resistivity;
setting the upper time limit based on the detected characteristic;
The cutting blade dressing method according to claim 4, characterized in that:

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