JPS6297805A - Dicing device - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field] The present invention relates to a dancing device suitable for use in cutting a semiconductor wafer into minute pellets.

[Background technology]

In the dicing process in which a semiconductor wafer on which predetermined elements have been formed is cut and separated into pellets, a dicing blade 2 with a disc-shaped grindstone 3 around its periphery is used as shown in FIG. 2, and the dicing blade 2 is rotated to separate the semiconductor wafer 1 is cut to a predetermined depth. The amount of protrusion of the disc-shaped grindstone 3 of this dicing blade 2 is approximately 600 μm, which is approximately 380 μm.
The wafer 1 is cut to a depth of .

By the way, in conventional dicing apparatuses, the amount of cuts into the wafer 1 described above is controlled based on the axial height of the dicing blade 2 with respect to the table 4 on which the wafer 1 is placed. When the disc-shaped grindstone 3 is worn away from its periphery, the amount that the disc-shaped grindstone 3 cuts into the wafer 1 changes even if the axial position of the dicing blade is controlled, and the depth of cut gradually increases. It will be reduced. For this reason, in the latter stage of dicing after processing a large number of lots, it becomes impossible to make cuts of sufficient depth, and in some cases, it may become impossible to separate into pellets in the subsequent process.

For this reason, until now, operators have controlled the axial position of the dicing blade 2 by visually determining the amount of wear on the disc-shaped grindstone 3, but this has resulted in the blade being replaced too early or being replaced too late. The former may cause economic disadvantage, while the latter may cause problems such as the center support portion of the dicing blade 2 interfering with the surface of the wafer 1 and damaging the elements on the wafer.

[Purpose of the invention]

SUMMARY OF THE INVENTION An object of the present invention is to provide a dicing apparatus that can control the amount of cut into a wafer or the like to always maintain a constant value, and can perform this control automatically.

The above and other objects and novel features of the present invention include:
It will become clear from the description of this specification and the accompanying drawings.

[Summary of the invention]

A brief overview of typical inventions disclosed in this application is as follows.

That is, by measuring and recording the height position at which the dicing blade, which moves relative to the table on which the dicing object is placed, comes into contact with the table, when necessary,
The value of the change in the height position of the dicing blade relative to the initial value can be determined, and the changed value corresponds to the amount of wear on the grinding wheel of the dicing blade, so the amount of wear on the grinding wheel of the dicing blade can be managed numerically. This is what I did. From this, it is possible to always form a constant amount of cuts regardless of the wear of the grindstone in the dicing blade, and dicing can be performed favorably and with high reliability.

〔Example〕

FIG. 1 is a diagram showing the overall configuration of an embodiment of the present invention,
Reference numeral 11 denotes a semiconductor wafer as a member to be diced, which is placed on a table 14 . Further, reference numeral 12 denotes a dicing blade, which has a disc-shaped grindstone 13 integrally formed around a center support portion 15 and is rotated by a rotating shaft 16 of a motor 17 . As is well known, the disk-shaped grindstone 13 is made of a metal such as nickel as a carrier, and diamond abrasive grains are supported in the metal. Further, the motor 17 is mounted on a support base 17a which is threadedly connected to a screw 18 extending in the vertical direction, and can be moved up and down by rotating the axis of this screw 18. When the motor 17 is moved downward, the semiconductor wafer Incisions can be made from the surface side. This screw 18 is rotated by a pulse motor 19 in forward and reverse directions.

On the other hand, the dicing blade 12 and the table 14
is connected to the control section 20, and the pulse motor 1
9 is also connected to the control section 20.

This control section 20 includes a measurement circuit 21, a storage circuit 22, a calculation circuit 23, and a comparison circuit 24, and can control the operation of the pulse motor 19 as described later. The measuring circuit 21 can measure the height position of the dicing blade 12 by counting the output pulses of the pulse motor 19.

Further, the calculation circuit 23 calculates the wear amount of the disc-shaped grindstone 13 based on the signals from the measurement circuit 21, the dicing blade 12, and the table 14, and further calculates the height of the dicing blade 12 during operation from this. Furthermore, the comparison circuit 24 compares the output signal of the calculation circuit 23 with the actual operating height of the dicing blade 12 at the current time, and outputs a signal for adjusting the height of the dicing blade 12 to the pulse motor 19. .

According to the above configuration, when dicing the semiconductor wafer 11 placed on the table 14, the pulse motor 19 is driven in advance to move the motor 17 coupled to the screw 18 downward, and at the same time, the dicing blade 12 is moved downward. . When the lower end of the dicing blade 12 contacts the table 14, the dicing blade 12 and the table 14 are electrically connected to form a closed circuit, and a predetermined signal is sent to the foot measurement circuit 21 of the control unit 20. At the same time, since the pulse signal from the pulse motor 19 is input to the measurement circuit 21, the measurement circuit 21 can measure the axial position of the dicing blade 12 and the lower end height of the disc-shaped grindstone 13 at that time. This height is stored in the storage circuit 22.

Next, the dicing blade 12 is moved while driving the pulse motor 19 to form cuts in the semiconductor wafer 11. During this time, the calculation circuit 23
The amount of wear on the disc-shaped grindstone 13 is calculated from the height of the dicing blade 12, and the amount of movement of the dicing blade 12 required to cut the semiconductor wafer 11 to a predetermined depth and its final position are calculated from this. Calculate height values. These calculated values are stored in the storage circuit 22.

Subsequently, the comparison circuit 24 counts the pulses output from the pulse motor 19 and compares the final height value of the dicing blade 12 stored in the storage circuit 22 with the current height of the dicing blade. Then, when the two match, a stop signal is output to the pulse motor 19.

As a result, the downward movement of the dicing blade 12 is stopped, and the dicing operation is completed.

Therefore, in this dicing device, the disc-shaped grindstone 13
Detects the height of the dicing blade when it contacts the surface of the table 14, calculates the moving height value of the dicing blade to obtain the required cutting depth based on this, and performs dicing at this height position. The semiconductor wafer 11 will be diced using the blade 12. In other words, by measuring and recording the height position at which the dicing blade, which moves relative to the table on which the workpiece to be diced is placed, comes into contact with the table when necessary, the height position of the dicing blade can be changed from the initial value. Since the changing value corresponds to the wear amount of the dicing blade grindstone, we decided to manage the wear amount of the dicing blade grindstone numerically. Thereby, even if the disc-shaped grindstone 13 of the dicing blade 12 is worn out and its radius length is shortened, it is possible to always cut a certain amount into the semiconductor wafer 11, and proper dicing can be realized. Further, even if it is desired to change the thickness or the cutting depth of the semiconductor wafer 11, this can be easily handled.

Note that if the initial height of the dicing blade 12, that is, the height at which the disc-shaped grindstone 13 contacts the table 14, is smaller than a predetermined value, this means that the wear of the grindstone 13 has exceeded the limit. Since it is stored in the memory circuit 22,
The need to replace the dicing blade can be determined immediately.

〔effect〕

(1) A measuring circuit that measures the height at which the dicing blade contacts the table on which the dicing object is placed and starts dicing, a memory circuit that records this measured value over time, and a Since it is equipped with a calculation circuit that calculates the height of the dicing blade during dicing operation based on the height of the dicing blade, it is possible to always form a constant amount of cuts regardless of the wear of the disc-shaped grindstone of the dicing blade, resulting in good dicing. It can be performed.

(2) The height position of the dicing blade is measured using the conduction caused by the contact between the dicing device and the table on which the dicing target is placed, so the height position of the dicing blade can be measured with high precision. , it is possible to further improve the stabilization of the depth of cut.

(3) Since the amount of wear of the disc-shaped grindstone can be known numerically from the record of the measured value of the height position of the dicing blade over time, it is possible to determine the wear amount of the disc-shaped grindstone between the dicing blade and the workpiece due to the wear of the grindstone of the dicing blade. Interference can be prevented and damage to the member to be diced can also be prevented.

Although the invention made by the present inventor has been specifically explained above based on Examples, it goes without saying that the present invention is not limited to the above Examples and can be modified in various ways without departing from the gist thereof. Nor. For example, instead of measuring the height position and the amount of downward movement of the dicing blade by counting the number of pulses from a pulse motor, a potentiometer may be attached to perform the measurement.

[Application field]

The above explanation has mainly been about the application of the invention made by the present inventor to dicing of semiconductor wafers, which is the field of application that formed the background of the invention. If so, the same can be applied.

[Brief explanation of drawings]

FIG. 1 is an overall configuration diagram showing a schematic configuration of an embodiment of the present invention, and FIG. 2 is a partial front view of a dicing apparatus for explaining a general method of dicing. 11... Member to be diced (semiconductor wafer), 12.
... Dicing blade, 13 ... Disc-shaped grindstone, 14
...Table, 15...Center support part, 16...Rotating shaft, 17...Motor, 18...Screw, 19...
Pulse motor, 20...control unit, 21...measuring circuit, 22...memory circuit, Fig. 1

Claims (1)

[Claims] 1. A dicing blade having a disc-shaped grindstone around the periphery,
A dicing device that forms a cut in a dicing member while moving the dicing member relative to a table on which the dicing member is placed, and measures the height position at which the dicing blade contacts the table and starts dicing when necessary. a memory circuit that records measurement values obtained by the measurement circuit over time;
A dicing apparatus comprising: a calculation circuit that calculates a height position during a dicing operation based on the dicing start height position. 2. The dicing apparatus according to claim 1, wherein the dicing blade and the table are each made of a conductive material, and the starting height of dicing is measured based on a closed circuit formed by contact between the two.