JP2838108B2 - Method for manufacturing semiconductor chip using sapphire as substrate - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial applications]

The present invention relates to a method for manufacturing a semiconductor chip using sapphire as a substrate, and particularly to a dicing method.

[Prior art]

Conventionally, sapphire has been widely used as an insulating substrate for epitaxial growth. Then, a semiconductor circuit is formed on the sapphire substrate by epitaxial growth. In the dicing of a wafer for chip production, similarly to the dicing of silicon or the like, dicing is performed by rotating a blade coated with artificial diamond at a high speed.

[Problems to be solved by the invention]

However, since sapphire is a very hard substance, it is difficult to dice under conditions for dicing ordinary silicon, gallium arsenide, or the like. That is, it is necessary to use a wide blade, rotate the blade at high speed, and have a high torque. For this reason, cracking and chipping of the cut portion, which is called chipping, is large and large, and the electrodes and the like fall off, causing many chip defects. In addition, if the cutting margin is increased in consideration of chipping, the number of chips that can be manufactured per wafer decreases. SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems, and an object of the present invention is to prevent chipping in dicing of a semiconductor wafer using sapphire as a substrate, to prevent generation of defective chips, and The purpose is to increase the number of chips that can be manufactured per wafer.

[Means for Solving the Problems]

According to a configuration of the invention for solving the above problem, in a semiconductor chip formed using sapphire as a substrate, a gallium nitride semiconductor is formed on an a-plane {110} of the sapphire substrate, and a c-axis (0001) of the sapphire substrate is formed. 55
This is a method for manufacturing a semiconductor chip in which a straight line in two directions that intersect at an angle equal to or less than a degree is defined as a chip boundary and separated along the boundary. According to a second aspect of the present invention, in a semiconductor chip formed using sapphire as a substrate, a semiconductor is formed on the a-plane {110} of the sapphire substrate and the c-axis (0001) of the sapphire substrate is 55 degrees or less. This is a method of manufacturing a semiconductor chip in which a straight line in two directions that intersect at an angle of not less than a degree is defined as a chip boundary and separated along the boundary. Further, the invention according to claim 3 is the invention according to claim 1, wherein the c-axis (0001) of the sapphire substrate is not more than 55 degrees.
A feature is that a straight line in two directions intersecting at an angle of not less than degrees is defined as a chip boundary and separated along the boundary.

[Action and effect]

The present inventor has determined by experiment that the a-plane of the sapphire substrate
At 0 °, dicing sapphire in a manner that intersects the c-axis (0001) at an angle of 55 degrees or less has been found to minimize chipping. Therefore, as described above, on the a-plane {110} of the sapphire substrate, it intersects the c-axis (0001) at an angle of 55 degrees or less.
A gallium nitride semiconductor crystal was grown using the straight line in the direction as the boundary of the chip, and the chip was separated by cutting along the boundary to reduce chipping. Further, since the chipping is small, the cutting margin can be reduced, and the number of chips per wafer can be improved. A semiconductor is formed on the a-plane {110} of the sapphire substrate, and a straight line in two directions crossing at an angle of 55 degrees or less and 35 degrees or more with respect to the c-axis (0001) of the sapphire substrate is defined as a chip boundary. Both the straight lines in two directions become 55 degrees or less,
Chipping of a straight line in two directions is effectively prevented. As a result, a rectangular chip with little chipping in both straight lines can be obtained.

【Example】

Hereinafter, the present invention will be described based on specific examples. As shown in FIG. 1, a rectangular sapphire substrate 1 having an upper surface a and a longer side having a c-axis was prepared. Next, the sapphire substrate 1 is fixed on a 6-inch silicon wafer with wax, and the sapphire substrate 1 is 0 degree, 30 degrees, 45 degrees, 60 degrees with respect to the c-axis 2.
Dicing was performed at 90 degrees and 90 degrees. A 150 μm-wide blade coated with artificial diamond was used for dicing. The dicing condition is the blade rotation speed.
The dicing speed was 24000 rpm and the dicing speed was 1 mm / sec. And
The dicing groove was observed. The results are shown in FIGS.
Shown in the figure. FIG. 7 shows the relationship between the dicing width and the dicing direction. According to the results shown in FIG. 7, when dicing is performed in a direction crossing the c-axis at an angle of 30 degrees or less, the dicing width is at least 19 mm.
It was constant at a maximum of 220 μm at 0 μm. The minimum value of the dicing width is constant at 190 μm irrespective of the dicing direction, but it can be seen that the maximum value of the dicing width rapidly increases when the direction exceeds 45 degrees with respect to the c-axis. Therefore, it is understood that good dicing is performed when dicing is performed at an angle of 55 degrees or less with respect to the c-axis. In order to dice a semiconductor wafer grown on a sapphire substrate into a square or a rectangle, the dicing is performed at 35 degrees to the c-axis.
It can be seen that good dicing of the chip is performed when it is performed in two orthogonal directions inclined at an angle of 55 degrees. In the best mode, if the chip is square or rectangular, it will be 45 degrees from the c-axis on the a-plane of the sapphire substrate.
It is best to perform dicing using two orthogonal straight lines as boundaries. Further, when a square or rectangular sapphire substrate is used, the number of chips that can be manufactured per wafer can be increased by using a substrate having each side at 45 degrees with respect to the c-axis. This dicing was also performed on a wafer in which N-type gallium nitride and I-type gallium nitride were grown on a sapphire substrate. The same result as described above was obtained with respect to chipping. That is, when dicing was performed in a direction crossing the c-axis at 55 degrees or less, good dicing with small chipping was performed.

[Brief description of the drawings]

FIG. 1 is an explanatory view showing a dicing direction of a sapphire substrate, and FIGS. 2, 3, 4, 5, and 6 are 0 degrees, 30 degrees, and 45 degrees with respect to the c-axis, respectively. FIG. 7 is a plan view showing a dicing groove when dicing is performed in a direction inclined at an angle of 60 degrees, 90 degrees, and FIG. 7 is a measurement diagram showing the relationship between the maximum value and the minimum value of the dicing width with respect to the dicing direction. 1 ... sapphire substrate, 2 ... c-axis

────────────────────────────────────────────────── ─── Continuation of front page (72) Inventor Masaki Mori 1 Ochiai Ogata, Nagasugai-gun, Nishi-Kasugai-gun, Aichi Prefecture Toyoda Gosei Co., Ltd. (56) References JP-A-53-90773 (JP, A) JP-A Sho 54-66767 (JP, A) (58) Fields investigated (Int. Cl. ⁶ , DB name) H01L 21/02 H01L 27/12 H01L 21/86 H01L 21/78

Claims (3)

(57) [Claims] 1. A semiconductor chip formed using sapphire as a substrate, wherein a gallium nitride semiconductor is formed on an a-plane {110} of the sapphire substrate, and a c-axis (0001) of the sapphire substrate is formed.
A method of manufacturing a semiconductor chip in which a straight line in two directions intersecting at an angle of 55 degrees or less with respect to the chip is defined as a chip boundary and separated along the boundary. 2. A semiconductor chip formed by using sapphire as a substrate, wherein a semiconductor is formed on an a-plane {110} of the sapphire substrate and the c-axis (0001) of the sapphire substrate is not more than 55 degrees and not more than 35 degrees. A method of manufacturing a semiconductor chip in which a straight line in two directions intersecting at an angle is defined as a chip boundary and separated along the boundary. 3. The sapphire substrate has a c-axis (0001) of 55
2. The method for manufacturing a semiconductor chip according to claim 1, wherein a straight line in two directions intersecting at an angle equal to or less than 35 degrees and equal to or less than 35 degrees is defined as a chip boundary and separated along the boundary.