JPH0982587A - Preparation of nonsquare electronic chip - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent the increase of chipping, cracking, or internal strains by cutting off electronic chips from a wafer having a hexagonal or trigonal substrate so that the side faces of the chips can be formed of the a-plane of the wafer. SOLUTION: On a wafer 30, a GaInN/AlGaN blue light emitting diode (purple color and green color LED) is formed on each sapphire substrate through the conventional process. The LEDs are respectively formed in numerous triangular areas 34 demarcated by numbers cutting lines 31, 32, and 33 drawn along the a-plane of the substrates and numerous triangle pole-like LED chips 35 having triangular areas 34 are obtained by cutting the wafer 30 along the cutting lines. The diameter of the electronic chip, in addition, is adjusted to about 5mm or smaller. Therefore, the occurrence of chipping, cracking, or internal strains can be reduced when the chips are cut off.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing a hexagonal electronic chip or a trigonal electronic chip, and more particularly to a method for cutting, separating or pelletizing a wafer on which electronic devices are integrated and a non-cutting method using the method. The present invention relates to an electronic component using a square electronic chip and a non-square electronic chip.
The present invention can be applied to both hexagonal electronic chips and trigonal electronic chips. In the following, even if only one is described for convenience of description, the description can be applied to both the hexagonal electronic chip and the trigonal electronic chip unless otherwise specified.

[0002]

BACKGROUND OF THE INVENTION As shown in FIG. 1, many semiconductor devices, electro-optical devices, micro-optical devices, etc. (hereinafter collectively referred to as electronic devices 1) are collectively formed on a suitable substrate 2 in a wafer process. It Next, these electronic devices 1 are taken out as separated electronic chips 10 by cutting the processed wafer 3 by an appropriate method, transferred to an assembly process, and completed as parts. This disconnection,
The separating step or pelletizing step (hereinafter referred to as cutting step) includes scribing, cleavage, cleavage, etc. in addition to the dicing shown in C of FIG. In this case, the wafer 3 is attached and fixed to the adhesive tape 5 attached to the carrier 4, and then cut by the blade 6.

In this separation step, it is desirable that the cut surface be uniform. If an unexpected chip or crack occurs, the yield of the semiconductor device may decrease, or the reliability such as malfunction may decrease. If a large margin is provided around the semiconductor device on the wafer in order to avoid such an undesired result, the number of semiconductor devices per wafer is reduced, and the price of parts using the same is increased.

Conventionally, the cut-out electronic chip has a rectangular or rectangular or rectangular outer shape. However, in recent years, various substrates have been used for integration of various electronic devices.
For example, III- such as InGaN, GaN, AlGaN, BGaN, BAlN, BGaInN described in the specification of Japanese Patent Application No. 23452, 1995-
Lasers and LEDs (light emitting diodes) composed of N-based semiconductors
It has been considered to integrate it on a SiC (silicon carbide) substrate or an Al2O3 (sapphire) substrate ZnS substrate.

These substrates are hexagonal crystals whose crystal structure is shown in FIG. 2C or trigonal crystals such as sapphire shown in FIGS. 2A and 2B. The electronic devices such as laser and LED are integrated on the c-plane of these substrates. Therefore, when a rectangular or rectangular electronic chip is to be cut out, two paired side surfaces of the side surfaces of the electronic chip can be along the a-plane of the substrate (that is, parallel to the a-plane). The other pair of two sides does not extend along the a-plane and intersects the a-plane. Therefore, the side surface intersecting the a-plane is not uniform, and the above-mentioned unexpected chip or crack is likely to occur. The range is typically several tens to several hundreds μm.

[0006]

SUMMARY OF THE INVENTION In the present invention, the side surface of an electronic chip cut out from a wafer provided with a hexagonal or trigonal substrate is made to be along the a-plane, so that the chip due to the cutting of the electronic chip Reduces cracks and internal strain. Since all sides are along the a-plane,
The outer shape of the chip is not square, that is, non-square.

[0007]

BEST MODE FOR CARRYING OUT THE INVENTION In FIG. 3, a wafer 30 is made by forming a GaInN / AlGaN blue LED (purple to green emission) on a sapphire substrate by a conventional process. Each LED is a on the board
It was formed in each of a large number of triangular regions 34 defined by a large number of cut lines 31, 32, 33 along the surface (A in FIG. 3). The wafer 30 is cut along the cutting lines to obtain a large number of triangular prism-shaped LED chips 35 (enlarged and displayed) having triangular regions 34 (B in FIG. 3). A hexagonal prism-shaped LED element 36 is formed in the triangular region 34, and an electrode 37 is provided in the n-type region near the apex of the chip. An electrode 38 is also provided in the p-type region on the top of the device region 36, and the LED regions 37, 38 are connected to the LED.
Drive current is supplied to. Light emitted toward the substrate is emitted. The outer shape of the LED element 36 forming a hexagonal column can also be along the a-plane.

In FIG. 4, the wafer 40 is the wafer 30.
GaInN / AlGaN blue LED (purple) on sapphire substrate
~ Green emission) is created by a conventional process.
Each LED has a large number of cutting lines 41, 4 along the a-plane of the substrate.
It was formed in each of a large number of hexagonal regions 44 divided by 2, 43. The wafer 40 is cut along these cutting lines to form a hexagonal column shape having a hexagonal region 44.
A large number of LED chips 45 can be obtained.

In FIG. 5, a wafer 50 is produced by forming a GaInN / AlInN stripe laser on a sapphire substrate by a conventional process (see the specification of Japanese Patent Application No. 23452, 1995 mentioned above). Each laser is formed in each of a large number of diamond-shaped regions 54 defined by a large number of cut lines 51 along the a-plane of the substrate and a large number of cleavage lines 52 along the a-plane. A portion 53 constituting a laser cavity in one rhombus region 54 is provided so as to bridge the opposing cleavage lines 52, and slightly protrudes to an adjacent rhombus region 54 while intersecting perpendicularly to the cleavage lines 52. ing.

In the cutting step, first, the wafer 50 is cleaved along the cleavage line 52, and a large number of elongated strips 55 are cut out. Then, the strip 55 is cut along the cut line 51 to obtain a laser chip 56. The side surface of the chip obtained by cleavage becomes the mirror surface of the laser resonator and outputs laser light. The order of the steps of cutting out may be reversed and the cleavage along the cleavage line 52 may be performed later, but the above order is more preferable.

Although the above description is different from the actual one in terms of physical dimensions and the number of regions for the sake of convenience of explanation, it is not considered to be an obstacle for those skilled in the art to understand the present invention. Further, the present invention is not limited to use for LEDs and lasers, but can be effectively used for other electric elements, micro-optical elements, micro-mechanical elements, etc. integrated on a crystal substrate.

[0012]

By implementing the present invention, chipping, cracking, and internal strain that accompany cutting of chips are reduced, and the performance and reliability of electronic components and the like are improved. Further, since the margin for cutting out can be reduced and the number of chips per wafer can be increased, the cost of electronic components and the like can be reduced. In particular, the effect is remarkable when a chip having a diameter of 5 mm or less is cut out.

[Brief description of drawings]

FIG. 1 is a diagram for explaining a wafer cutting step including a plan view (A) and a front view (B) of a wafer according to a conventional technique.

FIG. 2 is a hexagonal system (C) or a trigonal system (A,
It is explanatory drawing which shows the crystal structure of B).

FIG. 3 is a diagram for explaining a first embodiment of the present invention for cutting out a triangular prism LED chip.

FIG. 4 is a diagram for explaining a second embodiment of the present invention for cutting out a hexagonal prism LED chip.

FIG. 5 is a diagram for explaining a third embodiment of the present invention for cutting out a rhomboid laser chip.

[Explanation of symbols]

30, 40, 50 Wafers 31, 32, 33, 41, 42, 43, 51 Cutting lines 37, 38 Electrodes 52 Cleaving lines 35, 45 LED chips 55 Strips 56 Laser chips

Claims (4)

[Claims] 1. A wafer prepared by integrating one or a plurality of electronic devices on a hexagonal or trigonal crystal substrate is prepared, and at least one wafer is cut by cutting the wafer along the a-plane of the crystal substrate. A method for manufacturing a non-rectangular electronic chip, which comprises obtaining an electronic chip comprising the electronic device and the crystal substrate on which the electronic device is mounted. 2. The method of manufacturing a non-rectangular electronic chip according to claim 1, wherein the electronic chip has a diameter of about 5 mm or less. 3. The method for manufacturing a non-rectangular electronic chip according to claim 1, wherein the outer shape of the electronic chip is a triangle, a hexagon, or a rhombus. 4. The III-N device wherein the electronic chip emits purple to green light.
The method for manufacturing a non-rectangular hexagonal electronic chip according to claim 3, which is a light emitting diode.