JP2610484B2 - Automatic dressing device - Google Patents

Description

The present invention relates to an apparatus for automatically dressing a blade of an inner circumferential blade for cutting in an ingot into a thin wafer in a semiconductor manufacturing process. It is related.

<Background of the Invention> In a slicing machine, when the cutting condition is deteriorated, the cutting is performed from the cutting condition at that time, and the blade of the blade is appropriately dressed.

Here, the diamond diamond powder is fixedly formed on a metal plate, and dressing is performed by applying a fine-density grindstone to the metal plate.The dressing site is determined based on the bending direction of the blade during ingot cutting, cutting resistance, etc. Has been adjusted. Therefore, what kind of dressing is to be performed is determined by the operator, and an appropriate selection is not always made, which is not always rational.

In addition, there is a disadvantage that the operation involves manually pressing the dressing stick against the blade rotating at a high speed, which is dangerous.

An object of the present invention is to automatically and safely perform necessary processing.

<Overview of the Present Invention> FIG. 1 shows the overall schematic configuration of the present apparatus. However, various detectors used in the present apparatus are not shown.

Since various methods for detecting the operating state of the blade are currently being implemented, the detected value and the history of the blade up to the present are input to the storage device of the computer, and these are combined to obtain the most desirable action as the present condition. Is determined and selected, and a command for performing this is transmitted to the dressing device. For this purpose, the dressing device is provided with a function that fulfills a plurality of purposes.

Here, the history of the blade is, for example, how many wafers have been cut since the start of use, how many dressings have been performed during that time, how many wafers have been cut since the last dressing, blade replacement, tension How many times the survey was conducted, what cutting tendency is there, etc.
The process is selected with reference to this. Further, in the present invention, as one type of dressing, the shape of the blade can be corrected, that is, truing can be performed.

<Embodiment> In the present invention, the signal of the detector is input to a computer, and the signal is determined together with the history of the blade to determine a dressing treatment method. Therefore, an example of the detector related to the present invention will be described first.

A) Cutting resistance detector A wattmeter is used as a method for detecting the cutting resistance when the blade is rotated at high speed and the ingot is pressed and cut. In this method, a power consumption signal required until the cutting of one wafer is completed and a fluctuation signal of the power consumption during the process are sent to a computer to detect a cutting resistance. Another method is to detect a change in the number of revolutions of the spindle and send it to a computer,
There is a method of detecting the cutting resistance and the like.

B) Blade displacement detector A displacement detector is fixed slightly away from the blade surface to detect a change in the distance from the blade. This detects the displacement of one of the blades and the vibration, and sends them to the computer.

C) Detector of end face shape This is a detector for knowing the outline of the shape of the end face of the ingot when one wafer has been cut. In FIG. Is applied upward from below. The member 3 has projecting points 4 and 5 in the diameter direction, and the contact 7 of the upper and lower displacement detector 8 is provided upward at the center in the diameter direction. And projecting points 4,5
At a right angle to the space, a protruding point 6 is provided on the same diameter. Here, the protruding points 4, 5, and 6 are pressed against the end face 2, and the displacement (+) (-) of the contact 7 is detected with respect to the surface formed by the three points at that time. After performing the first measurement, the T-shaped member 3 is rotated by 90 ° to perform the measurement in the orthogonal direction, and the shape of the end face can be estimated by combining (+) and (−) of the measured values. . At this time, the direction and magnitude of the warpage from the reference plane are determined based on the displacement amount. It is considered that the warpage of the end face shape is mainly caused by the difference in sharpness between the upper and lower sides of the blade, that is, clogging on one side.

By using the above-described detector, various blade states such as clogging, blade spillage, blade runout, and the like of the blade blade portion from the detector data during and after cutting the ingot can be grasped.

Next, FIG. 3 shows an enlarged portion of the blade of the blade.
In the figure, reference numeral 10 denotes a blade made of a thin metal plate (referred to as a base metal). A grindstone blade 11 having diamond powder fixed to the inner circumference thereof is formed, and the ingot 1 is pressed against the blade in a rotating state to cut the wafer. . As a process for correcting the blade 11, the blade 11 is worn and deformed by cutting, and the deformation is corrected to a normal shape. This is called truing, and the parts shown in FIGS. 4a and 4b are modified.

This is the purpose of dressing, which is generally called dressing. The entire blade (Fig. 4a, b, c,
There is a full dressing to recover the sharpness of d), an upper dressing of a, a lower dressing of b, and a belly dressing of c and d.

For truing, a groove is formed in a hard diamond grindstone or ceramic grindstone, and a blade is inserted into the groove to rotate. For dressing, a dense whetstone (WA whetstone) is used, and the whetstone is pressed against the part to be sharpened, and the dressing is performed while grinding the whetstone.

In the present invention, the above operations are collectively referred to as dressing, and a device that performs this operation with one device is referred to as a dressing device.

In the present invention, as shown in FIG. 5, a dressing device for performing the above dressing with a dressing stick is used. Here, the dressing stick 12 is fixed to a shaft 13, and the shaft 13 is supported to be inclined with respect to the plane of the blade 10, and is rotated at a low speed, a linear motion in the longitudinal direction of the shaft, and a horizontal surface for pressing the stick against the blade 11. Movement is possible, and these movements can be performed simultaneously. Then, a part of the hard material grindstone 14 for truing is attached to the stick 12, and a groove 15 for truing is provided on this.

The grindstone 12 is used by cutting a cylindrical grindstone with a blade from left to right in FIG. 6 as shown in FIG. Alternatively, a precut may be used.

In addition, the sharpening of each part of a, b, c, d in FIG.
It is selectively performed as shown in the table below by a combination of the descent and the rotation direction.

This principle will be described below.

Considering the situation where the grindstone is rising while rotating clockwise (CW) in FIG. 5 (a), the cross section at the blade surface is as shown in FIG. In this state, the grindstone is actually ground at the blade edge as shown in the figure and at the left side of the center of the dressing grindstone. (Because the rotating shaft is inclined) And if the whetstone rises, it will be cut, so it will only hit the lower side of the cutting edge. Considering the moving direction of the whetstone at this time, as shown in Fig. 8 It can be seen that the grindstone is moving from the cutting edge of the blade toward the cutting edge.

Therefore, considering this grinding portion with a focus on the cutting edge, ninth
It looks like the figure. That is, in the operation of raising the grindstone by clockwise rotation (CW), as can be seen from the drawing, the tip portion of the blade (portion b in FIG. 4) is dressed.

Next, when the direction of rotation of the grindstone is reversed, that is, when the grindstone is raised by counterclockwise rotation (CCW), the moving direction of the grindstone is reversed as shown in FIG. The part (d) in FIG. 3) is dressed.

Also, when the grindstone descends, the same concept is used.
The selection of the dressing part is performed as follows.

FIG. 11 is a view showing truing, in which a blade is inserted into a groove 15 of a hard agent grindstone 14 fixed to the base of a stick 12 to correct the blade.

Here, various rotations and movements of the dressing stick are selectively performed by command signals from a computer.

In the above, the signal from each detector is input to the computer, and as soon as the blade condition is determined to require treatment, the signal is treated with reference to the above-mentioned history of the blade.

For example, when the power consumption suddenly increases, the standard power consumption is stored, and the abnormality is detected and output in comparison with the standard power consumption. In the case of using a spindle tachometer, an abnormal rotation speed is detected and output. Then, truing is performed assuming that blade spillage has occurred. For this purpose, an operation command is transmitted to the dressing device.

If it is detected that the signal from the blade displacement detector oscillates from the reference signal value, vibration is generated, so that it is determined that clogging is on the side of the cutting edge, and a command for abdominal dressing treatment is issued.

Further, when the end face shape is selected based on the measurement signal from the end face shape detector (see FIG. 2), and it is judged that the sharpness is partially reduced due to the difference between the output of the blade detector and the normal state. Sends a command to sharpen a predetermined portion.

Furthermore, when an abnormality of the blade displacement is detected by the output of the blade displacement detector, an instruction to replace the blade is displayed by referring to the history of the blade if the frequency of use since the previous truing is small is small. , The new wafer cutting is stopped.

<Effect> In the related art, the operator instantaneously judges the output signal of each detector and takes appropriate measures. During that time, the operation of the slewing machine was stopped, so there was no time to make a decision to take prompt measures from the viewpoint of improving efficiency. In the present invention, a program can be created in advance from a plurality of detected values and a history, so that a treatment error can be reduced to a minimum.

Therefore, the treatment can be performed effectively and immediately, so that the downtime of operation is short and the blade can be effectively used for a long life. And because everything can be done automatically, there is no danger and reasonable work can be done.

[Brief description of the drawings]

1 is an overall schematic diagram of an automatic dressing apparatus, FIG. 2 is an explanatory diagram showing an outline of an end face detector, FIGS. 3 and 4 are enlarged explanatory diagrams of a blade of a blade, and FIG. 5 is a dressing stick. 6, 7, 8, 9, and 10 are explanatory diagrams of a dressing operation, and FIG. 11 is an explanatory diagram of a truing operation. DESCRIPTION OF SYMBOLS 1 ... Ingot, 2 ... End face, 7 ... Contact of end face detector, 10 ... Blade, 11 ... Whetstone blade, 12 ... Dressing stick, 14 ... Hard material whetstone, 15 ... Groove

Claims (1)

(57) [Claims] In a slicing machine, the quality of a blade is judged from the outputs of a cutting resistance detector, an ingot end face shape detector, and a blade displacement detector required for cutting a wafer, and the dressing history of the blade is determined. And a storage device for storing the history of the wafer cutting shape at that time,
For the behavior of the blade obtained from the output of the detector from the storage data of this storage device, a dressing method of the blade of the blade is selected, and a command signal corresponding to this selects a grinding wheel for truing, and a grinding wheel for dressing. And a dressing device having a drive mechanism for setting the movement, rotation, and pressing direction of the dressing stick against the blade.