CN102903815A - Flip-chip light-emitting diode with roughened sides and manufacturing method thereof - Google Patents

Abstract

A flip-chip light-emitting diode with roughened sides and a manufacturing method thereof, wherein the flip-chip light-emitting diode with roughened sides includes: an upper substrate, a nucleation layer and an electron injection layer grown sequentially on the upper substrate, and the electron One side of the injection layer forms a mesa; a light-emitting layer is grown on the electron injection layer; a hole injection layer is grown on the light-emitting layer; a P electrode is made on the hole injection layer; an N electrode is made on the mesa of the electron injection layer Form the LED chip on the lower substrate; an insulating layer is grown on the lower substrate; a P wire electrode is made on one side above the insulating layer; an N wire electrode is made on the other side above the insulating layer to form a flip-chip substrate ; The P electrode of the LED chip is connected to the P wire electrode of the flip-chip substrate through metal solder balls; the N electrode of the LED chip is connected to the N wire electrode of the flip-chip substrate through metal solder balls. The light extraction efficiency can be greatly improved, so that the external quantum efficiency of the light-emitting diode is improved, and it is especially suitable for the production of large-sized power crystal grains.

Description

Flip-chip light-emitting diode with roughened sides and manufacturing method thereof

technical field

The invention belongs to the technical field of semiconductors, in particular to a flip-chip light-emitting diode with roughened sides and a manufacturing method thereof.

Background technique

Because light-emitting diodes have the advantages of energy saving, environmental protection, and long life, in the next few years, light-emitting diodes may replace traditional lighting fixtures such as incandescent lamps and fluorescent lamps, and enter thousands of households.

At present, in the front-mounted structure chip of the traditional light-emitting diode, the electrodes are located on the light-emitting surface of the chip, and due to the poor conductivity of the p-GaN layer, it is generally necessary to introduce a current spreading layer on the surface of the p-GaN layer, and the current spreading layer and the electrodes are both It will absorb part of the light and reduce the light efficiency of the LED. At the same time, due to the poor heat dissipation of the front-mounted structure, it is difficult to realize multi-chip integration. In order to overcome these shortcomings of the front-mounted chip, the American Lumileds company invented the flip-chip. However, due to the gap between the refractive index of the substrate material and the air, the light total reflection effect at the escape interface greatly restricts the light extraction of the light emitting diode device. T.Fujii, Y.Gao et al. in Appl.Phys.Lett.84 (2004) 855. proposed a gallium nitride-based light-emitting diode surface roughening technology to improve the extraction efficiency of light-emitting diodes. After that, surface roughening is a commonly used key technology to improve the light extraction efficiency of LEDs. However, the previous surface roughening technology mainly focused on the surface roughening of p-type gallium nitride, the surface roughening of indium tin oxide transparent conductive layer, the back roughening of sapphire substrate, and the side roughening of gallium nitride epitaxial layer, etc. It involves the roughening treatment of the light-emitting surface of the side wall of the sapphire substrate of the light-emitting diode.

This technology uses laser processing technology to process the side of the sapphire substrate of the flip-chip light-emitting diode, and obtains a rough sapphire side structure, which greatly improves the extraction efficiency of the light-emitting diode. This technology has obvious advantages, which greatly optimizes the process and greatly reduces the production cycle and cost.

Contents of the invention

The main purpose of the present invention is to provide a flip-chip light-emitting diode with roughened sides and a manufacturing method thereof, which is a method for roughening the sidewall of a gallium nitride-based light-emitting diode substrate in the process of making a light-emitting diode chip, which can The light extraction efficiency is greatly improved, so that the external quantum efficiency of the light-emitting diode is improved, and it is especially suitable for the production of large-scale power crystal grains.

In order to achieve the above object, the present invention provides a flip-chip light-emitting diode with roughened sides, comprising:

an upper substrate and a nucleation layer and an electron injection layer grown sequentially on the substrate, one side of the electron injection layer forming a mesa;

a light emitting layer grown on the electron injection layer;

a hole injection layer grown on the light emitting layer;

A P electrode, the P electrode is fabricated on the hole injection layer;

An N electrode, the N electrode is fabricated on the mesa of the electron injection layer to form an LED chip;

look at the substrate;

an insulating layer grown on the lower substrate;

A P-line electrode, the P-line electrode is made on the side above the insulating layer;

An N-wire electrode, the N-wire electrode is fabricated on the other side above the insulating layer to form a flip-chip substrate;

The P electrode of the LED chip is connected to the P wire electrode of the flip-chip substrate through metal solder balls; the N electrode of the LED chip is connected to the N wire electrode of the flip-chip substrate through metal solder balls.

The present invention also provides a method for manufacturing a flip-chip light-emitting diode with roughened sides, comprising the following steps:

Step 1: performing roughening treatment on the side of an upper substrate to form a continuous roughened surface or a discontinuous roughened surface;

Step 2: sequentially growing a nucleation layer, an electron injection layer, a light emitting layer and a hole injection layer on the upper substrate by MOCVD;

Step 3: Etching downward on the side above the hole injection layer, and the etching depth reaches the electron injection layer to form a mesa;

Step 4: making a P electrode on the unetched side above the hole injection layer;

Step 5: preparing an N electrode on the mesa of the electron injection layer to form an LED chip;

Step 6: growing an insulating layer on the substrate;

Step 7: making P-line electrodes and N-line electrodes on the insulating layer to form a flip-chip substrate;

Step 8: Flip-chip the LED chip on the flip-chip substrate by flip-chip welding or bonding, the P electrode of the LED chip is connected to the P wire electrode of the flip-chip substrate through metal solder balls; the N electrode of the LED chip It is connected with the N wire electrode of the flip-chip substrate through metal solder balls to complete the preparation.

Compared with the prior art, the present invention provides that only appropriate processing is added in the cutting process with chip technology, which is simple and easy to operate, and can greatly improve the light extraction efficiency, so that the external quantum efficiency of light-emitting diodes is improved, and is especially suitable for large-sized power-type crystal grains production.

Description of drawings

In order to further illustrate the technical content of the present invention, the present invention will be further described below in conjunction with accompanying drawing and embodiment, wherein:

1 is a schematic structural view of the first embodiment of the present invention, showing that the roughened side surface of the upper substrate is a triangular structure;

Fig. 2 is the second embodiment of the present invention, showing that the figure on the side of the upper substrate is a circular structure;

Fig. 3 is the third embodiment of the present invention, showing that the figure on the side of the upper substrate is a discontinuous structure;

Fig. 4 is the fourth embodiment of the present invention, showing that the figure on the side of the upper substrate is a continuous structure;

Fig. 5 is the fifth embodiment of the present invention, showing that the figure on the side of the upper substrate is a continuous structure, and the substrate is an inverted trapezoid;

Fig. 6 is the sixth embodiment of the present invention, showing that the figure on the side of the upper substrate is a discontinuous structure, and the upper substrate is semicircular or hemispherical;

Fig. 7 is a preparation flow chart of the present invention.

Detailed ways

Please refer to FIG. 1, the present invention provides a roughened flip-chip light-emitting diode, including:

An upper substrate 11 and a nucleation layer 12 and an electron injection layer 13 grown sequentially on the upper substrate 11, one side of the electron injection layer 13 forms a mesa 131, the depth of the mesa 131 of the electron injection layer 13 Less than the thickness of the electron injection layer 13, the material of the upper substrate 11 is sapphire, Si, SiC, GaAs or glass, the side surface of the upper substrate 11 is a continuous roughened surface or a discontinuous roughened surface, the upper substrate 11 The shape of the substrate 11 is rectangular, trapezoidal, semicircular or hemispherical, and the roughened side suppresses the total reflection effect of light inside the LED device, improving the light extraction efficiency of the device;

A luminescent layer 14, the luminescent layer 14 is grown on the electron injection layer 13, and the luminescent layer is a multi-quantum well structure;

A hole injection layer 15, the hole injection layer 15 is grown on the light emitting layer 14, wherein the material of the nucleation layer 12, the electron injection layer 13, the light emitting layer 14 and the hole injection layer 15 is GaN;

A P electrode 16, the P electrode 16 is made on the hole injection layer 15, and the P electrode is selected from the group consisting of nickel (Ni)/silver (Ag)/platinum (Pt)/gold (Au), nickel (Ni) /Silver (Ag)/Gold (Au), Nickel (Ni)/Silver (Ag)/Nickel (Ni)/Gold (Au), Titanium (Ti)/Aluminum (Al)/Titanium (Ti)/Gold (Au) , Titanium (Ti)/Silver (Ag)/Titanium (Ti)/Gold (Au), Aluminum (Al)/Silver (Ag)/Gold (Au), Aluminum (Al)/Titanium (Ti)/Gold (Au) A material in the metal mirror material group such as;

An N electrode 17, the N electrode 17 is fabricated on the mesa 131 of the electron injection layer 13 to form the LED chip 100;

The lower substrate 23, the material of the lower substrate 23 is a silicon chip, ceramics, circuit board or metal plate, which has good heat dissipation performance and is easy to realize multi-chip integration;

An insulating layer 22, which is a silicon dioxide layer or a silicon nitride layer, prevents a short circuit between the P line electrode 20 and the N line electrode 21, and grows on the lower substrate 23;

A P wire electrode 20, the P wire electrode 20 is made on the side above the insulating layer 22;

An N wire electrode 21, the N wire electrode 21 is fabricated on the other side above the insulating layer 22 to form a flip-chip substrate 200;

The P electrode 16 of the LED chip 100 is connected to the P wire electrode 20 of the flip-chip substrate 200 through metal solder balls 18 ; the N electrode 17 of the LED chip 100 is connected to the N wire electrode 21 of the flip-chip substrate 200 through metal solder balls 18 .

Referring to FIG. 2 is the second embodiment of the present invention, which shows that the figure on the side of the upper substrate is a circular structure.

Referring to FIG. 3 is a third embodiment of the present invention, which shows that the pattern on the side of the upper substrate is a discontinuous structure.

Referring to FIG. 4 is a fourth embodiment of the present invention, which shows that the graphics on the side of the upper substrate are continuous structures.

Referring to FIG. 5 is the fifth embodiment of the present invention, which shows that the pattern on the side of the upper substrate is a continuous structure, and the substrate is an inverted trapezoid.

Referring to FIG. 6 is the sixth embodiment of the present invention, which shows that the pattern on the side of the upper substrate is a discontinuous structure, and the upper substrate is semicircular or hemispherical.

Please refer to Figure 7 in conjunction with Figure 1. The present invention also provides a method for manufacturing a flip-chip light-emitting diode with roughened sides, comprising the following steps:

Step 1: roughening is carried out on the side of an upper substrate 11 to form a continuous roughened surface or a discontinuous roughened surface. The roughening of the side of the upper substrate 11 is performed on the upper substrate 11 The side surface forms an induced shape, and a triangular (see Figure 1), circular (see Figure 2), rhombus or polygonal roughened surface is corroded by the corrosive liquid, and the roughened surface is a continuous roughened surface (see Figure 4) Or discontinuous roughened surface (referring to Fig. 3), the material of upper substrate 11 is sapphire, Si, SiC, GaAs or glass, and the shape of this upper substrate 11 is rectangle, trapezoid (referring to Fig. 5), semicircular or hemispherical (see Figure 6);

Step 2: On the upper substrate 11, the nucleation layer 12, the electron injection layer 13, the light-emitting layer 14 and the hole injection layer 15 are sequentially grown on the upper substrate 11, and the nucleation layer 12, the electron injection layer 13, the light-emitting layer 14 and the The material of the hole injection layer 15 is GaN;

Step 3: Carry out dry etching by inductively coupled plasma ICP on the side above the hole injection layer 15, and the etching depth reaches the electron injection layer 13 to form a mesa 131, and the depth of the mesa 131 of the electron injection layer 13 is less than the thickness of the electron injection layer 13;

Step 4: Make a P electrode 16 on the unetched side above the hole injection layer 15, and the P electrode is selected from nickel (Ni)/silver (Ag)/platinum (Pt)/gold (Au), nickel (Ni)/Silver (Ag)/Gold (Au), Nickel (Ni)/Silver (Ag)/Nickel (Ni)/Gold (Au), Titanium (Ti)/Aluminum (Al)/Titanium (Ti)/Au (Au), titanium (Ti)/silver (Ag)/titanium (Ti)/gold (Au), aluminum (Al)/silver (Ag)/gold (Au), aluminum (Al)/titanium (Ti)/gold A material in the group of metal mirror materials such as (Au);

Step 5: Prepare the N electrode 17 on the mesa 131 of the electron injection layer 13 to form the LED chip 100;

Step 6: grow a layer of insulating layer 22 on the lower substrate 23, the insulating layer 22 is a silicon dioxide layer or a silicon nitride layer, to prevent the short circuit between the P line electrode 20 and the N line electrode 21, the lower substrate The material of 23 is a silicon chip, ceramics, circuit board or metal plate, and the material has good heat dissipation performance and is easy to realize multi-chip integration;

Step 7: making P-line electrodes 20 and N-line electrodes 21 on the insulating layer 22 to form a flip-chip substrate 200;

Step 8: Flip-chip the LED chip 100 on the flip-chip substrate 200 by flip-chip welding or bonding, the P electrode 16 of the LED chip 100 is connected to the P-wire electrode 20 of the flip-chip substrate 200 through metal solder balls 18 ; The N electrode 17 of the LED chip 100 is connected to the N wire electrode 21 of the flip-chip substrate 200 through metal solder balls 18 to complete the preparation.

The above examples are only used for illustrating the present invention, rather than limiting the present invention, and those of ordinary skill in the art can also make various transformations or changes without departing from the spirit and scope of the present invention; therefore, All equivalent technical solutions should also belong to the category of the present invention and should be defined by each claim.

Claims (10)

1. A flip-chip light-emitting diode with roughened sides, comprising: An upper substrate and a nucleation layer and an electron injection layer grown sequentially on the upper substrate, one side of the electron injection layer forming a mesa; a light emitting layer grown on the electron injection layer; a hole injection layer grown on the light emitting layer; A P electrode, the P electrode is fabricated on the hole injection layer; An N electrode, the N electrode is fabricated on the mesa of the electron injection layer to form an LED chip; look at the substrate; an insulating layer grown on the lower substrate; A P-line electrode, the P-line electrode is made on the side above the insulating layer; An N-wire electrode, the N-wire electrode is fabricated on the other side above the insulating layer to form a flip-chip substrate; The P electrode of the LED chip is connected to the P wire electrode of the flip-chip substrate through metal solder balls; the N electrode of the LED chip is connected to the N wire electrode of the flip-chip substrate through metal solder balls. 2. The flip-chip light-emitting diode with roughened sides according to claim 1, wherein the side surface of the upper substrate is a continuous roughened surface or a discontinuous roughened surface. 3. The flip-chip light-emitting diode with roughened sides according to claim 2, wherein the material of the upper substrate is sapphire, Si, SiC, GaAs or glass, and the shape of the upper substrate is rectangle, trapezoid, semicircle or hemispherical. 4. The flip-chip light-emitting diode with roughened sides according to claim 1, wherein the material of the lower substrate is a silicon wafer, ceramics, a circuit board or a metal plate. 5. The flip-chip light-emitting diode with roughened sides according to claim 1, wherein the depth of the mesa of the electron injection layer is smaller than the thickness of the electron injection layer. 6. A method for making a flip-chip light-emitting diode with roughened sides, comprising the steps of: Step 1: performing roughening treatment on the side of an upper substrate to form a continuous roughened surface or a discontinuous roughened surface; Step 2: sequentially growing a nucleation layer, an electron injection layer, a light emitting layer and a hole injection layer on the upper substrate by MOCVD; Step 3: Etching downward on the side above the hole injection layer, and the etching depth reaches the electron injection layer to form a mesa; Step 4: making a P electrode on the unetched side above the hole injection layer; Step 5: preparing an N electrode on the mesa of the electron injection layer to form an LED chip; Step 6: growing an insulating layer on the substrate; Step 7: making P-line electrodes and N-line electrodes on the insulating layer to form a flip-chip substrate; Step 8: Flip-chip the LED chip on the flip-chip substrate by flip-chip welding or bonding, the P electrode of the LED chip is connected to the P wire electrode of the flip-chip substrate through metal solder balls; the N electrode of the LED chip It is connected with the N wire electrode of the flip-chip substrate through metal solder balls to complete the preparation. 7. The method for fabricating a flip-chip light-emitting diode with roughened sides according to claim 6, wherein the depth of the mesa of the electron injection layer is smaller than the thickness of the electron injection layer. 8 . The method for manufacturing flip-chip light-emitting diodes with roughened sides according to claim 6 , wherein the material of the lower substrate is a silicon wafer, ceramics, a circuit board or a metal plate. 9. The method for manufacturing a flip-chip light-emitting diode with a side structure according to claim 6, wherein the side surface of the upper substrate is roughened by using a laser to form an induced shape on the side surface of the upper substrate, which is etched out by an etching solution. A triangular, rhombus, circular or polygonal roughened surface, wherein the roughened surface is a continuous roughened surface or a discontinuous roughened surface. 10. The method for making a flip-chip light-emitting diode with roughened sides according to claim 9, wherein the material of the upper substrate is sapphire, Si, SiC, GaAs or glass, and the shape of the upper substrate is rectangular, trapezoidal, semi- round or hemispherical.

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