JPH0376251A - Manufacture of semiconductor device - Google Patents

Abstract

PURPOSE:To surely split a wafer into chips at a high yield by a method wherein grooves are provided between adjacent semiconductor devices on the semiconductor wafer as scribing lines, the wafer provided with the grooves is subjected to a first thermal treatment, and a material whose thermal expansion coefficient is larger than that of the wafer is formed in the grooves, which is subjected to a second thermal treatment. CONSTITUTION:Grooves are provided between adjacent semiconductor devices 2 on a semiconductor wafer 1 as scribing lines 4. Then, the semiconductor wafer 1 is thermally expanded by a first heat treatment, whereby a first thermal strain 8 is induced in the semiconductor wafer 1 under the scribing line 4 through thermal expansion. Then, material such as metal 9 whose thermal expansion coefficient is larger than that of the semiconductor wafer 1 is formed in the scribing lines 4. Then, when the semiconductor wafer 1 is subjected to a second thermal treatment, as the metal 9 is larger than the semiconductor wafer 1 in thermal expansion coefficient, thermal strains 5a and 5b are caused in the semiconductor wafer 1, and thermal strain 5 as the net of them is generated in the semiconductor wafer 1. Then, when a mechanical force 6 is applied, the semiconductor wafer 1 is split into semiconductor chips 1a along the lines under which the second thermal strain 5 exists.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a method for manufacturing a semiconductor device that can reliably divide semiconductor chips on a semiconductor wafer.

[Conventional technology]

Conventionally, when dividing a large number of semiconductor chips formed on a semiconductor wafer 1 from a scribe line, as shown in FIG. As shown in Figure (a), by moving the diamond cutter 3 in the direction of arrow A in the figure, a scribe line is inserted as a scribe line 4. At this time, since an appropriate load is applied to the diamond cutter 3, the shape of the scribe line 4 becomes as shown in FIG.
Thermal strain 5 is caused. Next, when a mechanical force 6 is applied from the outside using a roller-type breaker or the like (not shown), the semiconductor wafer 1 is broken at the strain 5 and divided into semiconductor chips 1a as shown in FIG. 4(e). Ru.

The operations shown in Figures 4(a) to (C) are usually performed by attaching a film such as vinyl chloride with an adhesive to a semiconductor urchin.
This is done with the .

[Problem to be solved by the invention]

As shown in FIG. 5(a), the diamond cutter 3 in the method for dividing the semiconductor wafer 1 into chips as described above has the following features:
It is composed of a main body 3a and a diamond tip 3b at the tip, and as shown in FIG. The chip division state of the semiconductor chip 1a is determined by the load applied to the diamond cutter 3, that is, the cutting depth D of the scribe line 4 inserted into the semiconductor wafer 1, as shown in FIG. 5(C). Here, for example, the tip angle θ1 of the diamond tip 3b as shown in FIG. 6(a) becomes rounded due to friction, or the angle between the semiconductor wafer 1 and the diamond cutter 3 as shown in FIG. 5(b) is inappropriate. If the load of the diamond cutter 3 is too large, cracks 7 will occur in the scribe line 4 and thermal strain 5 will occur in multiple directions, as shown in FIG. 6(b). If an attempt is made to divide the wafer 1 and the semiconductor chip 1a, the portion of the semiconductor device 2 on the divided semiconductor chip 1a may break, as shown in FIG.
As shown in b), the semiconductor chip 1a may be diagonally broken. Furthermore, if the moving speed of the diamond cutter 3 shown in FIG. 4(a) is made too fast, the scribe line 4 will jump and a portion without the scribe line 4 will be created on the semiconductor wafer 1, making it impossible to divide it at all. Inconveniences such as the formation of parts occurred.

In this way, the conventional method of dividing the semiconductor wafer 1 into chips is as follows:
Diamond tip 3b at the tip of diamond cutter 3
It is necessary to adjust many items, such as the friction state of Since the distance between adjacent semiconductor devices 2 is usually very small, about 80 .mu.m, considerable skill is required to accurately cut a scribe line 4 in the center between them using a diamond cutter 3. Further, as a chip dividing method that does not use the diamond cutter 3, there is a method using a dicer, but when a dicer is used, it is necessary to widen the space between two adjacent semiconductor devices 2 to about 200μ+n or more. In this case, in the case of a semiconductor device used in an ultra-high frequency band in which GaAs is used as the material of the semiconductor wafer 1, the dimensions of the semiconductor device 2 itself are 200 μm square, so the number of semiconductor devices 2 per semiconductor wafer 1 is There were some inconveniences such as the amount being reduced by half.

The present invention was made to solve the above-mentioned conventional problems, and aims to provide a method for manufacturing a semiconductor device that can be divided into chips reliably and with a high yield.

[Means to solve the problem]

In the method for manufacturing a semiconductor device according to the present invention, grooves are formed by etching as scribe lines in the semiconductor wafer between a number of adjacent semiconductor devices formed on the semiconductor wafer, and after a first heat treatment, the grooves are removed. Forming a material having a larger coefficient of thermal expansion than the material for the semiconductor sea urchin in the part,
Thereafter, after performing a second heat treatment, there is a step of dividing into each semiconductor chip.

[Effect]

In this invention, grooves are formed by etching as scribe lines in the semiconductor wafer between a large number of adjacent semiconductor devices formed on the semiconductor wafer, and after the second heat treatment is performed, the grooves are filled with the semiconductor wafer. By forming a material with a larger coefficient of thermal expansion than the other material and performing the second heat treatment, mechanical strain due to heat is applied to the semiconductor wafer directly below the scribe line, and each of the semiconductor devices is reliably divided from the scribe line.

〔Example] An embodiment of the present invention will be described below with reference to the drawings.

FIGS. 1(a) to 1(g) are diagrams showing manufacturing steps of an embodiment of the method for manufacturing a semiconductor device of the present invention.

First, as shown in FIG. 1(a), grooves are formed as scribe lines 4 between semiconductor devices 2 on a semiconductor wafer 1 and adjacent semiconductor devices 2 by known photolithography and etching techniques. Next, a first heat treatment is performed. The semiconductor wafer 1 undergoes thermal expansion due to this heat treatment, but as shown in FIG. 1(b), the semiconductor wafer 1 directly below the scribe line 4 is heated! A first thermal strain 8 occurs due to tension. Next, as shown in FIG. 1C, a material having a higher coefficient of thermal expansion than the semiconductor wafer 1, such as gold WA9, is formed on the scribe line 4 by a known vacuum evaporation method or the like.

Ru. After that, when a second heat treatment is performed, the semiconductor wafer 1 and the metal 9 thermally expand. Here, since the metal 9 has a large coefficient of thermal expansion relative to the semiconductor wafer 1, as shown in FIG. 1(d), the thermal strain 5a and 5b
is added, the resultant force of these is thermal strain 5 (hereinafter referred to as the second
thermal strain 5) is applied to the semiconductor wafer 1. Here, as shown in FIG. 1(b), since the first thermal strain 8 has occurred in the semiconductor wafer 1 due to the first heat treatment, the second
As shown in FIG. 1 (el), the thermal strain 5 enters into the semiconductor wafer 1 in a larger amount than the original size.

Next, as shown in FIG. 1(f), after removing the metal 9 using known photolithography and etching techniques, the metal 9 is etched from the outside using a roller-type breaker (not shown) in the same manner as before. When mechanical force 6 is applied, semiconductor wafer 1 is broken at the second thermal strain 5 and divided into semiconductor chips 1a, as shown in FIG. 1(g). Here, Figure 1 (
The process 'L(g) may be performed with the semiconductor wafer attached to a film made of vinyl chloride or the like with an adhesive, as in the conventional method.

FIG. 2 shows another embodiment of the present invention, in which the grooves formed in the semiconductor wafer 1 between adjacent semiconductor devices 2 have a concave shape, and similar effects are expected.

In the above embodiment, a case was explained in which GaAs was formed on the semiconductor wafer 1 and metal 9 was formed on the scribe line, but various insulators, synthetic resins, etc. may be used as long as the coefficient of thermal expansion is large with respect to the semiconductor wafer 1. good.

Further, the width, depth, and shape of the scribe line, the metal material formed on the scribe line, the temperature of heat treatment, the temperature increase rate, etc. may be appropriately selected depending on the material, thickness, etc. of the semiconductor wafer 1.

Further, in the above embodiment, the division of the semiconductor wafer 1 has been described, but it goes without saying that the present invention can be applied to other than semiconductor wafers.

〔Effect of the invention〕

As explained above, in the present invention, a groove is formed by etching between adjacent semiconductor devices in a semiconductor unit made up of a large number of semiconductor devices, and then a first heat treatment is performed, and a first groove is formed directly below the groove. In the step of generating thermal strain, after attaching a material with a larger coefficient of thermal expansion than the semiconductor wafer onto the groove,
The process includes a step of performing a second heat treatment to generate a second thermal strain directly under the groove, and a step of dividing into each semiconductor chip after removing the material attached to the groove. It has the effect of being able to divide.

[Brief explanation of drawings]

FIG. 1 is a sectional view showing the manufacturing process of a semiconductor device according to one embodiment of the present invention, FIG. 2 is a sectional view showing another embodiment of the invention, FIG. 3 is a perspective view showing a semiconductor wafer, and FIG. The figure is a diagram explaining the steps of the conventional chip dividing method for semiconductor urchins, Figure 5 is a diagram showing a diamond cutter, Figure 6 is a diagram explaining a conventional scribe failure state, and Figure 7 is a diagram showing chip division. FIG. 3 is a diagram showing the state of a semiconductor chip when it is defective. In the figure, 1 is a semiconductor wafer, 2 is a semiconductor device, 5,
8 is the first. Second thermal strain, 6 is external mechanical force, 9
is metal. Note that the same reference numerals in each figure indicate the same or corresponding parts.

Claims (1)

[Claims] forming grooves by etching between adjacent semiconductor devices on a semiconductor wafer on which a large number of semiconductor devices are formed, and then performing a first heat treatment to generate a first thermal strain directly under the grooves; After depositing a material having a larger coefficient of thermal expansion than the semiconductor wafer on the groove, performing a second heat treatment to generate a second thermal strain directly under the groove; 1. A method of manufacturing a semiconductor device, comprising the step of removing material and then dividing into semiconductor chips.