JPH04354382A - Surface treatment method for gap light emitting element chip - Google Patents

Abstract

PURPOSE:To improve efficiency of light acquiring of a GaP light emitting element chip and to remove processing damage (dicing distortion) well simultaneously. CONSTITUTION:After a rough surface is formed by etching a surface of a GaP light emitting element chip by hydrochloric acid, it is etched by mixed solution consisting of sulfuric acid, hydrogen peroxide and water and is lastly etched by hydrochloric acid.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a surface treatment method for a GaP light emitting element chip, which improves light extraction efficiency and enables good removal of processing damage (dicing distortion).

0002

[Prior Art] In the process of processing a GaP LED chip, a GaP epitaxial wafer is subjected to processes such as vapor deposition, photo-etching, and sintering to form a p-electrode on one side of the substrate and an n-electrode on the other side. After forming the
A method is known in which the dicing is performed for separation and then the dicing distortion is removed by etching. As this etching solution, a sulfuric acid-based etching solution (a mixed solution of sulfuric acid: water: hydrogen peroxide), a hydrochloric acid etching solution, etc. are used. A sulfuric acid-based etching solution is suitable for removing dicing distortion, but has the disadvantage of reducing light extraction efficiency.On the other hand, a hydrochloric acid etchant contributes to improving light extraction efficiency, but is effective in removing dicing distortion. The problem was that it was not effective. This dicing distortion is L
It is known that it causes deterioration of ED chips.

[0003] A technique is also known in which these two types of etching solutions are used in combination. For example, if etching is performed with a sulfuric acid-based etchant and then with a hydrochloric acid etchant, this is suitable for removing dicing distortion, but there remains the problem that the light extraction efficiency cannot be improved. On the other hand, etching with a hydrochloric acid etchant followed by a sulfuric acid etchant is still suitable for removing dicing distortion, but does not eliminate the drawback of reduced light extraction efficiency. It wasn't done.

0004

[Problems to be Solved by the Invention] The present invention was invented in view of the problems of the prior art described above, and has improved light extraction efficiency and made it possible to effectively remove processing damage (dicing distortion). An object of the present invention is to provide a method for surface treatment of a GaP light emitting device chip.

[0005]

[Means for Solving the Problems] In order to solve the above problems, the surface treatment method for a GaP light emitting device chip of the present invention involves etching with hydrochloric acid to form a rough surface, and then etching it with sulfuric acid, hydrogen peroxide, and water. Etching is performed using a mixed solution consisting of the following: and finally etching is performed using hydrochloric acid.

In the first etching step, hydrochloric acid is used to roughen the surface of the GaP single crystal. To achieve this purpose, 30-85℃
It is preferable to treat for 5 to 180 minutes. Outside this temperature range and outside this processing time, the desired effects of the present invention cannot be achieved.

In the second etching step, sulfuric acid:
A solution containing water and hydrogen peroxide mixed in a volume ratio of 3:1:1 is used as an etching solution. Suitable etching conditions are 30-70°C for 3-30 minutes. Outside this temperature range and outside this processing time, the desired effects of the present invention cannot be achieved.

The third etching step may be performed under the same conditions as the first etching step.

[0009]

[Examples] The present invention will be described below with reference to Examples. Example 1 0.3 mm with AuBe electrode manufactured by conventional method
The corner GaP chip was subjected to an etching process consisting of the following three steps. First step: Treated with hydrochloric acid at 50 to 60°C for 20 minutes. 2nd step: Using a solution containing sulfuric acid: water: hydrogen peroxide in a volume ratio of 3:1:1,
It was treated at ℃ for 5 minutes. 3rd step: Using hydrochloric acid, 50-6
It was treated at 0°C for 20 minutes.

[0010] Ga
Luminance measurements and durability tests were conducted on the P chip. The brightness showed good values. Below, the brightness of this example is 10
The brightness of the comparative example is described as 0. In the durability test, 100 GaP chips were tested at room temperature for 100 seconds with a pulse current of 70 milliamps in wave height, 20% occupancy, and 100 Hz frequency.
This was done by measuring the brightness after driving for a certain period of time. Even after the durability test, all chips maintained a brightness of 95% or more of the value before the test. Note that an improvement in light extraction efficiency contributes to an improvement in brightness, and an improvement in durability means a reduction in processing damage (dicing distortion).

Comparative Example 1 A GaP chip similar to that of the example was heated to 50-60% with hydrochloric acid.
Etching treatment was performed at ℃ for 20 minutes. The brightness measurement and durability test were similarly conducted on the GaP chip that had been subjected to this single etching process. The brightness showed a relative value of approximately 100 as in the example, but the brightness after the durability test clearly decreased, with 11% of the cases dropping to 30% of the initial value.
There was also.

Comparative Example 2 A GaP chip similar to that of Example was prepared using a solution containing sulfuric acid: water: hydrogen peroxide in a volume ratio of 3:1:1.
After treatment at 0°C for 5 minutes, treatment with hydrochloric acid at 50-60°C for 2
Etching was performed for 0 minutes. The brightness measurement and durability test were similarly conducted on the GaP chip that had been subjected to the two-step etching process. The rate of decrease in brightness after the durability test was the same as in the example, but the initial brightness was 83 relative to the value in the example.

Comparative Example 3 A GaP chip similar to that of the example was heated to 50-60% with hydrochloric acid.
After etching at 60° C. for 20 minutes, a solution containing sulfuric acid: water: hydrogen peroxide mixed in a volume ratio of 3:1:1 was used for 5 minutes at 60° C. The brightness measurement and durability test were similarly conducted on the GaP chip that had been subjected to the two-step etching process. The rate of decrease in brightness after the durability test was the same value as in the example, but the initial brightness showed a relative value of 75 to the value in the example.

[0014]

[Effects of the Invention] As described above, according to the GaP chip etching method of the present invention, it is possible to improve the luminance of light emission, effectively remove processing damage (dicing distortion), and manufacture GaP chips that are less susceptible to deterioration. can.

Claims (1)

[Claims] [Claim 1] G characterized by etching with hydrochloric acid to form a rough surface, followed by etching with a mixed solution of sulfuric acid, hydrogen peroxide, and water, and finally etching with hydrochloric acid.
A method for surface treatment of an aP light emitting element chip.