CN103811624A - Encapsulation-free type UVLED (Ultraviolet Light-Emitting Diode) chip - Google Patents

Abstract

The invention relates to an encapsulation-free UVLED chip, which includes a substrate, and an N-GaN layer, a light-emitting layer, a P-GaN layer and a reflective layer are sequentially arranged on the front of the substrate; it is characterized in that: on the reflective layer, P- Through holes are set in the GaN layer and the light-emitting layer, and the through holes extend from the reflective layer to the bottom of the light-emitting layer, and the through holes communicate with the N-GaN layer; N eutectic electrodes are set in the through holes and on the surface of the reflective layer. P eutectic electrodes are arranged on the surface of the layer. The N eutectic electrode is flush with the upper surface of the P eutectic electrode. The encapsulation-free UVLED chip of the present invention has small thermal resistance and good heat dissipation, and the encapsulation-free technology can be used to reduce the internal stress of eutectic encapsulation.

Description

Package-free UVLED chip

technical field

The invention relates to an encapsulation-free UVLED chip, which belongs to the technical field of semiconductor encapsulation.

Background technique

Most of the packaging methods of LED chips in the prior art are relatively complicated, and the heat dissipation during the packaging process is not good. However, most of the non-encapsulation technologies adopt flip-chip packaging in the way of planting gold balls, and there are certain difficulties in using flip-chip packaging for the existing LED chip structure.

Contents of the invention

The purpose of the present invention is to overcome the deficiencies in the prior art, and provide an encapsulation-free UVLED chip with small thermal resistance and good heat dissipation. Encapsulation-free technology can be used to reduce the internal stress of eutectic encapsulation.

According to the technical solution provided by the present invention, the encapsulation-free UVLED chip includes a substrate, and an N-GaN layer, a light-emitting layer, a P-GaN layer and a reflective layer are sequentially arranged on the front of the substrate; it is characterized in that: A through hole is set in the reflective layer, the P-GaN layer and the light-emitting layer, the through hole extends from the reflective layer to the bottom of the light-emitting layer, and the through hole communicates with the N-GaN layer; N common is set in the through hole and the surface of the reflective layer The crystal electrode is provided with a P eutectic electrode on the surface of the reflective layer.

The N eutectic electrode is flush with the upper surface of the P eutectic electrode.

The encapsulation-free UVLED chip of the present invention has small thermal resistance and good heat dissipation, and the encapsulation-free technology can be used to reduce the internal stress of eutectic encapsulation.

Description of drawings

Fig. 1 is a structural schematic diagram of the present invention.

Fig. 2 is a schematic cross-sectional view of the present invention.

Detailed ways

The present invention will be further described below in conjunction with specific drawings.

As shown in Figure 1 and Figure 2: the encapsulation-free UVLED chip includes P eutectic electrode 1, N eutectic electrode 2, reflective layer 3, P-GaN layer 4, light emitting layer 5, N-GaN layer 6, lining Bottom 7, through hole 8, etc.

As shown in Figure 1 and Figure 2, the encapsulation-free UVLED chip of the present invention includes a substrate 7, and the substrate 7 can be a sapphire substrate, etc., and an N-GaN layer 6 and a light-emitting layer 5 are sequentially arranged on the front of the substrate 7 , P-GaN layer 4 and reflective layer 3; through holes 8 are set in the reflective layer 3, P-GaN layer 4 and light emitting layer 5, the through holes 8 extend from the reflective layer 3 to the bottom of the light emitting layer 5, the through holes 8 communicates with the N-GaN layer 6; an N eutectic electrode 2 is arranged in the through hole 8 and on the surface of the reflective layer 3, a P eutectic electrode 1 is arranged on the surface of the reflective layer 3, and the N eutectic electrode 2 and the P eutectic The upper surface of electrode 1 is flush;

The P eutectic electrode 1 and the N eutectic electrode 2 use a Cr/Pt/Au/Sn metal layer, and the thickness of the Sn metal is not less than 3 μm; the reflective layer 3 is an Al/Ni/Au metal layer, and the reflective layer 3 The material is mainly Al, and the reflective layer 3 is in 4-ohm contact with the P-GaN layer through the Ni/Au metal layer, and the reflectivity in the violet 365-420nm band range reaches more than 85%.

The preparation method of the encapsulation-free UVLED chip adopts the following steps:

Step 1: using MOCVD equipment to grow and form N-GaN layer 6, light-emitting layer 5 and P-GaN layer 4 on sapphire substrate 7, and the light-emitting wavelength can be changed by changing the temperature during the growth process;

Step 2: using an ICP device to etch the shape of the through hole and the N eutectic electrode 2 on the light emitting layer 5 and the P-GaN layer 4;

Step 3: Make reflective layer 3 on P-GaN layer 4 using electron beam evaporation equipment, the metal of reflective layer 3 is Al/Ni/Au, the main body of reflective layer 3 is Al, the thickness of Ni/Au is 1~5nm, as the ohm The contact layer is in contact with the P-GaN layer 4;

Step 4: Make P eutectic electrode 1 on reflective layer 3 by using electron beam evaporation equipment and thermal resistance evaporation equipment, and make N eutectic electrode 2, P eutectic electrode 1 and N eutectic electrode 2 on N-GaN layer 6 Color and metal layer Cr/Pt/Au/Sn, wherein the thickness of the Sn layer is not less than 3 μm; when making the N eutectic electrode 2, after evaporating the metal layer on the through hole etched in step 2, the N eutectic The through hole 8 of the electrode 2 is connected to the N-GaN layer 6;

Step 5: Use thinning and grinding equipment to thin the wafer to 100~200um, and then use a laser cutting machine to separate the devices on the wafer.

The present invention realizes the same height of the P eutectic electrode 1 and the N eutectic electrode 2 through the design of the through hole 8 electrodes, which is beneficial to improve the bonding effect of the metal layer during reflow soldering and reduce the internal stress of the eutectic package; the present invention The main material of the P eutectic electrode 1 and N eutectic electrode 2 is Sn, and the solder flux is used to solidify the crystal, and the eutectic method of oxygen-free reflow soldering can avoid the problem of Sn oxidation in an oxygen-free environment; it can realize low thermal resistance packaging, test The thermal resistance of the test package is less than 2°C/W, and the eutectic thrust is greater than 2000g.

Claims (2)

1. An encapsulation-free UVLED chip, including a substrate (7), on the front of the substrate (7), an N-GaN layer (6), a light-emitting layer (5), a P-GaN layer (4) and a reflective Layer (3); it is characterized in that: a through hole (8) is set in the reflective layer (3), P-GaN layer (4) and light emitting layer (5), and the through hole (8) is formed by the reflective layer (3) Extending to the bottom of the light emitting layer (5), the through hole (8) communicates with the N-GaN layer (6); an N eutectic electrode (2) is arranged in the through hole (8) and on the surface of the reflective layer (3) , setting a P eutectic electrode (1) on the surface of the reflective layer (3). 2. The encapsulation-free UVLED chip according to claim 1, characterized in that: the upper surface of the N eutectic electrode (2) is flush with the P eutectic electrode (1).

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