JPH0458546A - Cutting method for semiconductor wafer - Google Patents

Abstract

PURPOSE:To prevent a cutter from being clogged by a method wherein a relief which has exposed the face of a semiconductor wafer is formed so as to correspond to a dicing line in a solder layer formed on the rear of the wafer and the wafer is cut along the relief by using the cutter. CONSTITUTION:Relieves 4a which have exposed the face of a semiconductor wafer 6 are formed so as to correspond to dicing lines by a cutter 1 in a solder layer 4 formed on the rear of the wafer. Then, the rear of the semiconductor wafer 6 is pasted on a tape 5. The semiconductor wafer 6 is cut along the dicing lines corresponding to the relieves 4a from the surface side of the semiconductor wafer 6 by using the cutter 1; and a wafer-shaped semiconductor device is separated into chip-shaped semiconductor devices 3. Thereby, the solder layer 4 does not adhere to the tip of the cutter 1, and it is possible to prevent the cutter 1 from being clogged.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a method for cutting wafer-shaped semiconductor devices into individual independent semiconductor devices.

[Prior Art] As shown in FIG. 2, in a conventional wafer cutting method, a wafer 6 attached to a tape 5 is cut into individual semiconductor devices 3 using a cutter l rotating at high speed. In addition, the semiconductor device that is the object to be cut is a semiconductor (Si,
GaAs) and a solder layer (Au) 4 for fixing the chip-shaped semiconductor device to the external lead frame.
It has two layers.

As shown in FIG. 2, it consists of two different layers: a semiconductor (Si, GaAs) and a solder layer (Au), and the solder layer 4
Since the material is mainly composed of Au, it is soft and the tip of the cutter becomes clogged, making it difficult to cut.

If cutting is continued in such a state, defects will occur on the cut surface, and if it continues further, stress will be added and cracks will occur, making it necessary to replace the cutter 1. Therefore, in the past, the cutter 1 had to be replaced frequently for cutting.

Problems to be solved by the invention C] In this conventional wafer cutting method, the solder layer (Au)
4, the tip of cutter 1 gets clogged,
It was difficult to maintain the initial cut surface. Also the third
If the cutting depth is adjusted to prevent cutting into the solder layer 4 as shown in the figure, clogging will not occur and there will be no effect on the cutting blade, but it will cut into individual semiconductor devices 3, which is the ultimate purpose of cutting. The problem was that the method shown in Figure 3 was not an effective countermeasure.

An object of the present invention is to provide a semiconductor wafer cutting method that solves the conventional problems by eliminating clogging of cutting blades.

[Means to solve the problem]

In order to achieve the above object, a method for cutting a semiconductor wafer according to the present invention includes a relief forming step and a cutting step, wherein the relief forming step is performed by forming a film on the back surface of the semiconductor wafer. This is a step in which a cutout exposing the wafer surface is formed in the solder layer corresponding to the dicing line by a cutter, and the cutting step is to cut the semiconductor wafer with a cutter along the dicing line corresponding to the cutout, This is a step of separating a wafer-like semiconductor device into individual chip-like semiconductor devices, and the width of the relief is wider than the width of the cutter.

[Function] The present invention prevents clogging of the cutter by providing a relief corresponding to the dicing line by the cutter in the solder layer formed on the back surface of the semiconductor wafer and eliminating the solder layer at the cutting position of the cutter. It is something to be eliminated.

〔Example〕

Hereinafter, one embodiment of the present invention will be described with reference to the drawings.

FIG. 1 is a diagram showing an embodiment of the present invention.

In the figure, before attaching the semiconductor wafer 6 to the tape 5, the solder layer 4 formed on the back surface of the semiconductor wafer is cut with a cutout 4a that exposes the wafer surface.]
The dicing line is formed in accordance with the dicing line. In the embodiment, the recesses 4a are formed in a lattice shape so as to go around the chip-shaped semiconductor device 3. Also, the width of the relief 4a Q1
is set wider than the width Q1 of cutter 1.

Thereafter, the back side of the semiconductor wafer 6 is attached to the tape 5.

Next, by rotating the cutter 1 pivotally supported on the spindle 2 at high speed, the cutter 1 cuts the semiconductor wafer 6 from the front side of the semiconductor wafer 6 along the dicing line corresponding to the wafer 4a, thereby forming a wafer-shaped semiconductor device. The semiconductor devices 3 are separated into individual chip-like semiconductor devices 3.

According to the present invention, since the wafer surface is exposed on the back side of the wafer 6 to be cut by the cutter 1, the solder layer 4 will not adhere to the tip of the cutter 1, and the cutter 1 will not be clogged. .

In the embodiment, a disc-shaped blade rotating at high speed is used as the cutter 1, but the invention is not limited to this.

[Effects of the Invention] As explained above, the present invention does not use a cutter to cut the solder layer formed on the back surface of a semiconductor device, so the cutter does not become clogged and the life of the cutter is extended. This has the effect that it can be cut without cracking or chipping on the cut surface between each semiconductor device, and that the manufacturing yield can be improved.

[Brief explanation of drawings]

FIG. 1 is a diagram showing an embodiment of the present invention, and FIG. 2 is a diagram showing an embodiment of the present invention. FIG. 3 is a diagram showing a conventional method. 1...Cutter 2...Spindle 3...
・Semiconductor device 4...Solder layer 5...Tape 6...Semiconductor wafer patent applicant
NEC Co., Ltd. Diagram 2 Diagram

Claims (2)

[Claims] (1) A semiconductor wafer cutting method comprising a relief forming step and a cutting step, wherein the relief forming step involves dicing the relief with the wafer surface exposed on a solder layer formed on the back surface of the semiconductor wafer using a cutter. The cutting process is a process of cutting the semiconductor wafer with a cutter along the dicing line corresponding to the relief, and separating the wafer-shaped semiconductor devices into individual chip-shaped semiconductor devices. A method for cutting a semiconductor wafer, characterized in that: (2) The method for cutting a semiconductor wafer according to claim (1), wherein the width of the relief is wider than the width of the cutter.