JPH0431818B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention is a method for processing semiconductor wafers using a precision processing device such as a dicer or slicer that is equipped with a thin rotary grindstone having a circular shape such as a disk shape or an annular shape. The present invention relates to a method for compensating wear of a rotary grindstone when dicing a magnetic head or grooving a magnetic head.

(Purpose of the invention) In the technology of dicing a semiconductor wafer or cutting grooves on a magnetic head using a precision processing device equipped with a circular and thin rotary grindstone, depending on the type of workpiece, In recent years, there has been a demand for selective use of rotary grindstones at the expense of wear resistance. As a result, wear of the rotary grindstone often affects machining accuracy, resulting in the problem that wear compensation of the rotary grindstone must be performed frequently.

For example, a technique for dicing a semiconductor wafer with a dicer will be specifically described below.

The rotary grindstone of a dicer, which is normally used for dicing semiconductor wafers, has the disadvantage of easily causing chipping of semiconductor wafers, but it has the advantage of low wear rate, that is, excellent wear resistance. , an electrodeposited grindstone is used.

However, in recent years, when dicing wafers of individual semiconductors (also called discrete),
A situation has arisen in which it is difficult to use an electroplated grindstone which has excellent wear resistance and does not require compensation for wear during machining.

In other words, the chip size of individual semiconductors is significantly smaller than that of semiconductors that form integrated circuits such as ICs and LSIs, so the number of chip materials formed on a wafer of the same diameter is smaller than that of semiconductors that form integrated circuits such as ICs and LSIs. There are far more individual semiconductor wafers than formed semiconductor wafers! As a result, the same applies to the number of vertical and horizontal streets that divide the chip material.

Streets are parts that are cut and removed by dicing, but in individual semiconductor wafers, as mentioned above, there are many streets, so
There is a tendency that the area occupied by the streets on the wafer becomes larger and the effective usable area of the wafer becomes lower.

In recent years, there has been a demand for increasing the effective usable area of individual semiconductor wafers and improving wafer yield, and devices with narrower street widths have appeared. When dicing such individual semiconductor wafers using an electroplated grindstone as in the past,
Although it is unlikely that the machining accuracy of the groove exceeds the tolerance range due to wear of the grinding wheel, the chipping that occurs will reach the chip material due to the narrow street width, resulting in a problem that the product quality of the chip will deteriorate. . Therefore, when dicing individual semiconductor wafers having narrow streets, it is difficult to use an electroplated grindstone as in the conventional method. On the other hand, when dicing is performed using a resin bond grinding wheel, there is almost no chance of chipping to the extent that it degrades the product quality of the chips, but the grinding wheel wears out at an extremely high rate, and the chips must be formed on a single wafer. Due to the large number of grooves,
In order to keep the machining accuracy of the groove within the tolerance range, it is necessary to frequently compensate for the wear of the grindstone during the machining of one wafer.

Furthermore, among the individual semiconductor wafers mentioned above, wafers whose outer periphery is covered with molten glass have appeared, and when performing dicing processing using a resin bonded grindstone, it is necessary to perform wear compensation of the grindstone more frequently. It is.

As seen in the above semiconductor wafer dicing process, in recent years it has sometimes been necessary to selectively use a rotating grindstone at the expense of wear resistance, and as a result, the processing accuracy of the workpiece has to be kept within the tolerance range. To achieve this, a problem arises in that wear compensation for the rotating grindstone must be performed frequently during machining.

However, a wear compensation method that is suitable and simple for performing the above-mentioned wear compensation has not been developed so far.

For example, when grooving a semiconductor wafer using a grooving device equipped with a rotary grindstone, there is a method in which the wear of the rotary grindstone is compensated for each time the grooving of one semiconductor wafer is completed. It is stated in the No. That is, the semiconductor wafer mounting table is slowly raised from the non-operating position to the rotating grindstone, the point of contact is electrically detected, and the uncut amount of the groove is determined using the position of the table at the point of contact as a reference point. The table is lowered by an amount corresponding to the depth of the groove, and the depth of the groove is set. After that, all the grooves are processed on one semiconductor wafer, the table is brought into contact with the rotating grindstone again, and the difference between the position of the table at that point and the reference point, that is, the amount of wear of the rotating grindstone is measured. Then, when the error reaches a predetermined amount, the rotating grindstone is dressed. After dressing, the table is brought into contact with the rotary grindstone to set the depth of cut in the same manner as described above, and a new semiconductor wafer is placed on the table to form grooves. Thereafter, wear compensation for the rotary grindstone is performed in the same manner.

The method for compensating for the wear of the rotary grindstone is to compensate for the wear of the rotary grindstone every time the groove processing of one semiconductor wafer is completed, and as in the case of processing the individual semiconductor wafers, This method is difficult to apply to devices where wear compensation must be performed frequently during processing of a single wafer.

As another wear compensation method, a method has been developed in which the amount of wear on the rotary grindstone is constantly detected during machining and the wear is compensated according to the amount of wear, but the equipment for carrying out this method has a complicated configuration and It becomes expensive.

As described above, the conventional rotary grindstone wear compensation method is hardly suitable for performing wear compensation of the rotary grindstone during groove machining of a single workpiece.

In order to solve the above-mentioned conventional problems, the present invention performs a dicing process on a semiconductor wafer using a precision processing device such as a dicer or a slicer that is equipped with a thin rotary grindstone having a circular shape such as a disk shape or an annular shape. Another object of the present invention is to provide a method for compensating for the wear of a rotary grindstone, by which the machining accuracy of the groove can be kept within an allowable error range by compensating for the wear of the rotary grindstone using simple means when cutting grooves on a magnetic head. The purpose is to

(Structure of the Invention) The present invention is applicable to dicing a semiconductor wafer or machining grooves on a magnetic head using a precision processing device equipped with a disc-shaped or annular circular and thin rotary grindstone. , the total amount of wear of the rotary grindstone caused by machining grooves on one workpiece is determined by the length of the groove and the number of grooves machined, depending on the workpiece, the rotary whetstone, the machining conditions, etc. In particular, it is determined by the length of the groove, that is, by detecting the length of the groove machined at each processing point, it is possible to approximately grasp the amount of wear on the rotary grindstone.
It was invented based on this knowledge.

The present invention provides a method for abrasion compensation of a rotary whetstone when grooving a workpiece using a precision machining device equipped with a circular and thin-walled rotary whetstone. A wear compensation method for a rotary grindstone, characterized in that the amount of wear is set in advance based on the relationship between the amount of wear obtained from experimental results and experience and the length of the machined groove. By periodically performing a set amount of wear compensation at the set times during groove machining, it is possible to compensate for the wear of the rotary grindstone so that the machining accuracy is always within the tolerance range. It is.

That is, the configuration of the present invention is such that, in the wear compensation accuracy of the rotary whetstone when machining grooves on a workpiece using a precision machining device equipped with a rotary whetstone, the amount of wear of the rotary whetstone caused by machining the groove is reduced. is a groove length within the tolerance range of groove machining accuracy and a wear compensation amount corresponding to the wear amount of the rotary grindstone,
A wear compensation method for a rotary grindstone, characterized in that each time the length of the groove is machined, wear compensation is performed on the rotary grindstone by the amount of wear compensation.

As described above, the present invention sets the timing and amount of wear compensation for the rotary grindstone based on the relationship between the amount of wear and the length of the machined groove obtained from experimental results and experience, Machining accuracy can be maintained within tolerance. That is, the timing for abrasion compensation of the rotary grindstone is set according to the machining length of the groove, and the amount of wear compensation is set as an amount corresponding to the amount of wear of the rotary whetstone corresponding to the machining length of the groove.

The machining length of the groove to be set can be set by the cutting feed amount and/or the number of index positioning operations corresponding to the groove to be machined in the workpiece. Specifically, this can be done by setting the amount of movement of the table on which the workpiece is placed and/or the rotating grindstone. The amount of wear compensation of the rotating grindstone can be set by increasing the cutting depth of the rotating grindstone. Specifically, this can be done by setting the amount of movement of the table on which the workpiece is placed and/or the rotating grindstone.

(Example) The present invention will be explained in detail based on examples.

This example describes a method for compensating for wear of a rotary grinding wheel when cutting grooves on an individual semiconductor wafer whose outer periphery is covered with molten glass using a dicer equipped with a circular and thin rotary grinding wheel made of a resin bonded grinding wheel. , characterized in that each time a predetermined number of grooves are machined that produce an amount of wear that maintains the machining accuracy of the grooves within a tolerance range, the depth of cut of the rotary grindstone is increased by an amount equivalent to the amount of wear. This is a wear compensation method for a rotating grindstone (hereinafter abbreviated as a grindstone).

As explained in the above section of the object of the invention, individual semiconductor wafers have more chip materials than semiconductor wafers on which integrated circuits such as ICs and LSIs are formed. There are also many streets divided into !? For example, if the wafer diameter is 100 mmφ, a semiconductor wafer on which integrated circuits such as IC and LSI are formed is 4 mm x 4 mm.
Chips with dimensions of mm and 50 streets are formed, whereas individual semiconductor wafers have
A chip with dimensions of 0.4 mm x 0.4 mm and 500 streets are formed.

As mentioned above, individual semiconductor wafers tend to have a large number of streets and a low effective usable area, but in recent years, individual semiconductor wafers with narrower streets have appeared in order to increase the effective usable area of the wafer. There is.

When dicing an individual semiconductor wafer with narrowed street widths using a dicer,
As explained in the above section of the object of the invention, it is difficult to use an electrodeposited grindstone which has excellent wear resistance because it causes chipping which deteriorates the product quality of the chip material, so a resin bonded grindstone is often used.

When using a resin bonded grinding wheel, chipping hardly occurs, but due to its low wear resistance, grinding wheel wear compensation must be performed frequently to keep the groove machining accuracy within tolerance. is necessary.

For example, wafer diameter 100mmφ, wafer thickness 300μm,
Thick-walled individual semiconductor wafer with 500 streets
In the dicing process in which a groove of 200 μm in depth is formed using a resin-bonded grinding wheel with a diameter of 20 μm, a diameter of 50 mm, and a rotation speed of 30,000 rpm, the amount of wear on the electroplated grinding wheel can be reduced by processing a single individual semiconductor wafer. While it is about 1 μm, it reaches about 100 μm. In general, semiconductor wafers are fractured after dicing and formed into chips, so the processing accuracy of the depth of the grooves machined into the street, that is, the amount of uncut material, is not strict and is within the range of tolerance. is approximately ±10 μm for an uncut amount of 100 μm. Therefore, it is necessary to perform wear compensation at least 10 times during the processing of one individual semiconductor wafer.

Since the amount of wear on the grinding wheel is proportional to the length of the groove being machined, the time to perform wear compensation is when the amount of wear on the grinding wheel reaches a value set within the tolerance of the groove machining accuracy. It is desirable to set it according to the length of the groove to be machined. However, in the dicing process, the groove machining accuracy is not required to be as strict as mentioned above, so even if it is set according to the number of grooves to be machined, the groove machining accuracy can be kept within the tolerance range. Can be maintained.

That is, since a semiconductor wafer is circular, the streets along the chord passing through the center are long, and the streets along the chord passing through the periphery away from the center are short. As a result, we found that there is a slight difference in the amount of wear on the grindstone when machining grooves on a street along the string passing through the center and when machining a groove on a street along the string passing through the periphery away from the center. arise. That is, the amount of wear in the former is somewhat greater than in the latter. Therefore, when performing wear compensation corresponding to the average wear amount of the grindstone per groove, the former will be undercompensated, and the latter will be overcompensated. However, the number of grooves machined in the streets in two orthogonal directions on a semiconductor wafer is 250 each, and the number of grooves formed within a semicircular arc in each direction and the number of grooves machined in each direction are 250. The amount of wear on the grinding wheels is the same, but each
125 lines and 25 μm. Furthermore, the average amount of wear of the grindstone per groove is 0.2 μm. Machining 125 grooves in a semicircular arc in each direction will cause the grinding wheel to wear by 25 μm, but in order to keep the groove machining accuracy within the tolerance range, for example, the grinding wheel must be replaced every 25 grooves. Abrasion compensation of 5 μm is performed, which corresponds to the average amount of wear. In this case, in the first half of the semicircular arc where grooves are machined in one direction, groove machining was started from a shorter than average street along the chord passing through the periphery away from the center, and 25 grooves were completed. later,
A wear compensation of 5 μm is performed. After that, a wear compensation of 5 μm is performed every time a groove is machined on 25 streets in sequence, and after the groove is machined on a street that is longer than the average along the string near the center and the wear compensation is performed for the fifth time, the grinding wheel is is set to the position of In other words, when the first 25 streets were grooved, the amount of wear on the grinding wheel was smaller than the average amount of wear.
Compensating for wear of 5 μm results in overcompensation. or,
From then on, each time a groove is machined on 25 streets,
Wear compensation of 5 μm is performed, but since the actual position of the grinding wheel is set by the difference between the cumulative amount of wear on the actual grinding wheel and the cumulative amount of wear compensation, the state of wear compensation each time is different from each other. It is not only affected by excess or deficiency, but also by the difference between the cumulative amount of wear on the grindstone and the cumulative amount of wear compensation. Therefore, when a groove is machined on a longer than average street along the string near the center and the fifth wear compensation is performed, the fifth wear compensation itself is insufficient compensation, but due to the difference in the cumulative amount. , the grinding wheel is set to the initial position without over-compensating or under-compensating for wear. That is, in the first half of the semicircular arc, irrespective of the length of the groove machined into the street, the wear compensation each time is excessively compensated within the tolerance of machining accuracy. On the other hand, in the second half of the semicircular arc, contrary to the first half of the semicircular arc, groove machining starts from a longer than average street along the chord near the center, and after completing 25 grooves, 5μm of wear occurs. Since compensation is provided, compensation is insufficient. Therefore, wear compensation that is performed sequentially thereafter is performed with insufficient compensation within the tolerance of machining accuracy, and in the fifth wear compensation, the grinding wheel is set to the initial position without over or under compensation. .

As described above, when grooves are machined on streets in one direction of a semiconductor wafer, wear compensation corresponding to the average amount of wear is performed for each predetermined number of grooves to be machined, so that the length and shortness of the grooves to be machined can be adjusted. The excess or deficiency of wear compensation occurs based on the arrangement of the grooves to be machined, rather than the excess or deficiency of wear compensation based on. However, as mentioned above, the wear compensation is insufficient in the first half of the semicircular arc, and the wear compensation is overcompensated in the second half of the semicircular arc, but in both cases, the processing accuracy of the groove is within the allowable error range, so in the dicing process of semiconductor wafers. Even if the timing for performing wear compensation is set depending on the number of grooves to be machined, the groove machining accuracy can be maintained within the tolerance range.

It goes without saying that by setting the timing for performing wear compensation short, the margin of excess or deficiency in wear compensation can be reduced.

This embodiment will be explained based on the drawings.

FIG. 1 is a schematic side view of a dicer that implements the method of this embodiment, and FIG. 2 is a schematic plan view of the dicer shown in FIG. 1. FIG. 3 is a diagram explaining the position of the rotary grindstone in each operating state and the relationship therebetween, where a, b, and c represent the reference positioning operating state of the rotating grindstone, the operating state of grooving, and the position after grooving, respectively. The position of the rotary grindstone in the operating state immediately before starting groove machining is shown. FIG. 4 is a schematic plan view of an individual semiconductor wafer, showing every 25 streets in which grooves are formed. FIG. 5 is an explanatory diagram of the cutting feed operation of the rotary grindstone during groove processing of a semiconductor wafer, and is shown by the operating position of the rotary grindstone shaft. FIG. 6 is a diagram illustrating the state of wear compensation of the rotary grindstone when machining grooves in one direction street on a semiconductor wafer. Shown by association. FIG. 7 is a circuit diagram showing an example of a device for abrasion compensation of a rotating grindstone.

The configuration of a dicer that implements the method of this embodiment will be explained based on FIGS. 1 and 2.

1 is a machine base, 2 is a main table that reciprocates on the machine base 1 in the direction of the X arrow (hereinafter referred to as the X-axis direction), 3 is a rotating turntable, and 4 is a table on which individual semiconductor wafers are placed. This is a check table. 5 is a sliding table that reciprocates in the direction of the Y arrow (hereinafter referred to as the Y-axis direction). 6 is the sliding table 5
The pulse motor provided on the top, 7 is a feed screw,
8 is an actuating plate. 9 is a swinging arm; 10 is a swinging bearing provided on the sliding table 5; 11 is a conductive rotating grindstone supported by the swinging arm 9; Direction of the Z arrow (hereinafter referred to as Z-axis direction) by the pulse motor 6 via the moving arm 9
It moves back and forth. Reference numeral 12 denotes a numerical control device that controls the operation of the main table 2, turntable 3, and slide table 5 drive devices (not shown) and the pulse motor 6. X, Y, Z and θ are control signals for controlling the drive device, respectively.

The manner in which the method of this embodiment is carried out using the dicer having the above configuration and the operation of the dicer will be described.

The dicer performs various operations such as reference positioning of the rotary grindstone, grooving operation, and wear compensation of the rotary grindstone as described below, according to a program preset in the numerical control device.

First, the reference positioning of the rotary whetstone 11 is an operation for determining a reference point for setting the cutting depth of the rotary whetstone 11, and is performed without placing the individual semiconductor wafer W on the chuck table 4. Figure 3a
As shown in and b, the rotary grindstone 11 is slowly lowered while being rotated at the same speed as when machining the groove, for example, 30,000 rpm. When the rotating whetstone 11 comes into contact with the surface (also referred to as the reference surface) of the chuck table 4, and the contact is electrically detected and the reference position is set, the whetstone 11 immediately moves an appropriate amount in the Z-axis direction. This prevents unnecessary wear on the chuck table 4. Then, based on the reference position, the rotary grindstone 1
1 is set. Furthermore, in order to electrically detect the contact between the rotary whetstone 11 and the chuck table 4, the rotary whetstone 11 and the chuck table 4 are provided with electrical conductivity, and an electrical detection circuit ( (not shown) is provided. In a, b and c of Fig. 3, O ₀ −O ₀ ,
O ₁ −O ₁ , O ₂ −O ₂ , O ₃ −O ₃ are the axial centers of the rotary grindstone 11 immediately after grooving, immediately before starting grooving, at the start of reference positioning, at the time of reference positioning, and at the time of first cutting positioning, respectively. Indicates the location of

Next, the operation of forming grooves on the individual semiconductor wafer W will be explained.

After the first cutting position of the rotary grindstone 11 is set as described above, the individual semiconductor wafer W is placed on the chuck table 4. The individual semiconductor wafers W are arranged at equal intervals in two orthogonal directions.
There are 250 streets formed, and first, grooves are sequentially machined into the streets arranged in one direction. That is, the sliding table 5, which is indexed and positioned intermittently in the Y-axis direction at the same intervals as the array intervals of the streets, is indexed and positioned so that the rotary grindstone 11 matches the first street. Next, the main table 2, which reciprocates in the X-axis direction through a constant stroke with a slow forward stroke and a fast backward stroke, is moved, and a groove is machined in the first street. Thereafter, the rotating grindstone 11 is moved to a position where it does not contact the wafer W, that is, the axial center position of the rotating grindstone is O ₀ -O ₀ as shown in C in FIG.
The main table 2 is raised to the position shown in FIG. Next, the sliding table 5 is indexed and positioned so that the rotary whetstone 11 is aligned with the second street, the rotary whetstone 11 is set to the cutting position, and the main table 2 is moved to cut a groove in the street. Process. Thereafter, the same operation is repeated to groove all the streets in one direction, and then the turntable 3 is rotated 90 degrees to groove the streets in the other direction.

Next, compensation for wear of the rotary grindstone 11 will be explained.

In the groove machining operation, the numerical control device 12 is programmed in advance to perform wear compensation of 5 μm every time 25 streets are grooved.

The following description will be made based on FIGS. 4 to 6.

As shown in FIG. 4, the streets to be grooved are shown by solid lines every 25th when they are arranged in one direction, and by dotted lines every 25th when they are arranged in the other direction. P ₁ , P ₂ , ..., P ₉ , P ₁₀ each represent a group of 25 streets arranged in one direction,
FR indicates front and rear semicircular arcs, respectively.

The state of wear compensation is as shown in FIG. 5, and is indicated by the cutting feed operation of the rotary grindstone 11. In Figure 5, the horizontal axis is time, and the vertical axis is the third
The rotary grindstone 11 immediately before the start of groove machining after groove machining shown in the figure
The axial center position of the rotary grindstone 11 is shown based on the axial center position O ₀ -O ₀ of .

In addition, d is the groove machining state, e is the index positioning state, ΔZ is the wear compensation amount, P ₁ , P ₂ , ...,
P _o shows the state in which grooves are machined in every 25 street groups shown in FIG. 4.

As shown in FIG. 5, after grooving the first street of the street group _P1 , the axial center position of the rotary grindstone 11 is raised to position _O0 - _O0 ,
After index positioning e, for grooving the second street, it is lowered to the same position as for grooving the first street. Thereafter, in the same way, rotating grindstone 1
1 is moved up and down, and after grooving the 25th street, which is the last of the P ₁ street group, it rotates when it starts grooving the 26th street, that is, the first street of the P ₂ street group. Whetstone 11
From the case of the street group of P ₁ , the axis center position of is ΔZ=
It is lowered by an additional 5 μm. That is, wear compensation of ΔZ=5 μm is performed. Thereafter, wear compensation is sequentially performed in the same manner.

When the lengths of the grooves to be machined in each street group are the same, the wear is compensated for just the right amount by performing the wear compensation as shown in FIG. However, as shown in FIG. 4, since a semiconductor wafer has a circular shape, there is a slight difference in the length of the street group between the center and the peripheral area away from the center. As a result, when performing wear compensation as shown in Figure 5,
The actual wear compensation of the rotating grindstone 11 is as shown in FIG. In FIG. 6, the horizontal axis represents the number of grooves to be machined, and the vertical axis represents the position of the outer peripheral edge of the rotary grindstone from the bottom of the first groove to be machined. P ₁ , P ₂ ,
. . . , P ₉ , P ₁₀ indicate the order in which the street groups corresponding to FIGS. 4 and 5 are grooved. Rotating whetstone 1
The position of the outer periphery of item 1 is based on the average amount of wear per groove if there is no wear compensation, or based on the amount of wear depending on the length of each groove to be machined if there is wear compensation. .

As shown in Figure 6, the wear compensation by groove machining of the street groups from P ₁ to P ₅ is excessively performed.
Although the wear compensation due to groove machining of the street groups P ₆ to P ₁₀ is insufficient, wear compensation can be made to maintain the groove machining accuracy within the tolerance range for both streets.

Therefore, in this example, even if there is some difference in the length of the groove machined before performing wear compensation, by performing wear compensation as shown in FIG. As shown, wear compensation can be performed so that the machining accuracy of the groove is within the tolerance range.

Note that when grooving the streets in one direction of an individual semiconductor wafer, wear compensation can be performed to maintain the groove machining accuracy within the tolerance range, but the same applies when grooving the streets in the other direction. It can be done.

As described above, in this embodiment, the timing of wear compensation is set in advance in the numerical control program by setting the number of grooves to be machined and the amount of wear compensation as an amount corresponding to the average amount of wear based on the number of grooves to be machined. By setting, all the grooves on the individual semiconductor wafer can be processed with processing accuracy within the tolerance range.

In this example, lithium tantalate,
It can also be effectively applied when dicing wafers of highly crystalline compound semiconductors such as lithium niobate and gallium arsenide, when cutting grooves on magnetic disks, and when using metal resin bond grinding wheels. . Furthermore, the method of this embodiment can be applied even to electrodeposited grindstones or metal bonded grindstones that have excellent wear resistance when wear compensation is required.

Furthermore, as means for controlling wear compensation, other than numerical control, control means such as sequence control, program control, copying control, etc. can be employed.

Next, a modification of the numerical control device in the apparatus for carrying out the method of this embodiment will be described with reference to FIG.

The device for abrasion compensation of the rotating grindstone shown in Fig. 7 is as follows:
It can be used by being incorporated into the apparatus shown in FIGS. 1 and 2.

6 is a pulse motor, and 12 is a numerical control device. 13 is a preset counter that counts the command pulses sent from the numerical control device 12 for cutting feed in the Y-axis direction, and the counted value is a predetermined number that sets the timing of wear compensation. This is a repeatable preset counter or divider that emits an output pulse every time the number of grooves matches, and is automatically reset. Reference numeral 14 denotes a pulse distributor, which is a multiplication circuit that transmits a fixed number of pulses each time the preset counter 13 transmits an output pulse. 15 is an OR circuit, 16 is a pulse power supply circuit for driving the pulse motor 6, and 17 is a polarity control circuit.

Command pulses from the numerical control device 12 are counted by a preset counter 13, and when the counted value reaches a predetermined number, an output pulse is transmitted. The output pulse is applied to the pulse power supply circuit 16 via the OR circuit 15 in the same way as a drive signal for the normal pulse motor 6 transmitted from the numerical control device 12 . The pulse power supply circuit 16 outputs the same number of pulse motor drive pulses as the input signal pulses, and the pulse motor drive pulses are supplied to the polarity control circuit 1.
7 to the pulse motor 6.

As described above, each time the number of grooves set in the preset counter 13 is completed, the pulse distributor 1
The rotary grindstone 11 is moved by a predetermined amount in the Z-axis direction in proportion to the number set to 4 to compensate for wear. Therefore, in this modification, it is possible to compensate for the wear of the rotary grindstone, regardless of the program of the numerical control device.

(Effects of the Invention) The present invention can be applied even when wear compensation must be performed frequently depending on the workpiece, the grindstone, the processing conditions, etc. By setting in advance the timing and amount of wear compensation for the rotary grindstone based on the relationship between the amount of wear and the length of the groove to be machined, wear compensation is performed so that the machining accuracy of the groove is always within the tolerance range. can be done.

Furthermore, the present invention allows the timing and amount of wear compensation for the rotary grindstone to be set in advance, so that numerical control, sequence control, program control, or can be easily implemented by simple means such as tracing control.

[Brief explanation of drawings]

FIG. 1 is a schematic diagram of a dicer for carrying out the method of the embodiment. FIG. 2 is a schematic plan view of the dicer shown in FIG. 4 is a schematic plan view of an individual semiconductor wafer, and FIG. 5 is a schematic plan view of an individual semiconductor wafer.
FIG. 6 is an explanatory diagram of the cutting feed operation of the rotary whetstone, FIG. 6 is an explanatory diagram of abrasion compensation of the rotary whetstone, and FIG. 7 is an explanatory diagram of a device for abrasion compensation of the rotary whetstone. 1...Machine stand, 2...Main table, 3...Turntable, 4...Chick table, 5...
Sliding table, 6...Pulse motor, 7...Feed screw,
8... Operating plate, 9... Rocking arm, 10... Rocking bearing, 11... Rotating grindstone, 12... Numerical control device,
P ₁ ~ P _o ... Every 25th street group to be grooved,
ΔZ...Amount of wear compensation, O ₀ -O ₀ ...Axis position of the rotary grindstone immediately before starting groove machining after grooving, O3 _{-O3 ...} Axis position of the rotary grindstone when positioning the first cut,
F, R...Semicircular arcs before and after the individual semiconductor wafer.

Claims (1)

[Claims] 1. In the wear compensation method of the rotary whetstone when machining grooves on a workpiece using precision machining equipment equipped with a rotary whetstone, the amount of wear of the rotary whetstone caused by machining the groove is determined by the allowable machining accuracy of the groove. A wear compensation amount corresponding to the length of the groove, which is an error range, and an amount of wear of the rotary grindstone is set in advance, and each time the length of the groove is machined, wear compensation is performed on the rotary grindstone by the amount of wear compensation. A wear compensation method for a rotary grinding wheel, characterized in that: