CN102903812A

CN102903812A - Light emitting diode structure capable of eliminating stress and manufacturing method thereof

Info

Publication number: CN102903812A
Application number: CN201110211373XA
Authority: CN
Inventors: 吴东海; 李志翔; 蔡炯棋
Original assignee: NANTONG TONGFANG SEMICONDUCTOR CO Ltd
Current assignee: NANTONG TONGFANG SEMICONDUCTOR CO Ltd
Priority date: 2011-07-27
Filing date: 2011-07-27
Publication date: 2013-01-30

Abstract

The invention discloses a light emitting diode structure capable of eliminating stress and a manufacturing method thereof and relates to the technical field of photoelectricity. The light emitting diode structure comprises a sapphire substrate and an epitaxial layer disposed on the sapphire substrate, and is characterized in that criss-cross cutting scratches are formed inside the sapphire substrate. Compared with the prior art, the light emitting diode structure is capable of reducing stress produced in an epitaxial growth process of GaN-based LED materials and improving uniformity of GaN-based LED epitaxial materials and good yield of GaN-based LED chips, and beneficial to further size expansion of an epitaxial substrate.

Description

A kind of light emitting diode construction that can eliminate stress and preparation method thereof

Technical field

The present invention relates to field of photoelectric technology, light emitting diode construction that particularly can eliminate stress and preparation method thereof.

Background technology

Recently, the third generation semiconductor technology take the GaN material as representative becomes after Si, GaAs and again to attract the high-new semiconductor technology that catches people's attention.GaN base blue-green light LED LED succeeds in developing, realized all standing of LED for visible light wave range, simultaneously because LED-based lighting technology has energy-saving and environmental protection, nonhazardous, pollution-free, fast response time, solid light source, antidetonation, shock resistance, the characteristics such as compact, daily life field that LED has penetrated into us now widely is such as fields such as signal designation and information demonstrations; Backlight for liquid crystal display source, open air and room lighting field; The radiation illumination function field of the special dimension such as biological, medical etc.General illumination is that LED uses the most potential field, also is the ultimate aim of semiconductor lighting.The lighting source of white light LEDs green energy conservation, luminous efficiency have surpassed 10 times of incandescent lamp, reach 100,000 hours useful life, the current era that is becoming tight in energy day, and LED enters the general illumination field and has undoubtedly very large market prospects.

Most crucial technology is the MOCVD epitaxial growth of III-V hi-nitride semiconductor material in GaN base blue green light LED manufacture process, it has directly determined the crystal mass of III-V hi-nitride semiconductor material, also determined simultaneously consistency and the stability of the every photoelectric parameter of led chip, and the output yield of led chip.The GaN based compound semiconductor material of most mainly is to adopt the method epitaxial growth of metallo-organic compound chemical vapor deposition MOCVD on sapphire Al2O3 substrate.Yet, because lattice constant and thermal coefficient of expansion is different between Sapphire Substrate and the GaN based material, in the nitride material epitaxial process, because the effect of stress causes the warpage of Sapphire Substrate easily, can be because the inequality of substrate stress when serious, and cause breaking of Sapphire Substrate, thereby cause the reduction of product yield.Therefore, blue green light LED epitaxial wafer, the chip industryization of III-V group nitride material system still are in 2 inches levels at present.GaN base blue green light LED epitaxial wafer adopts more, and the challenge of large-sized substrate mainly is how to solve the stress problem that produces in the material epitaxy growth course.In the process that adopts MOCVD technology epitaxial growth III-V group nitride material, warpage generally can occur because being in stress state in epitaxial wafer.The generation of stress mainly contains following two kinds of situations: a kind of is the coefficient of thermal expansion mismatch stress that variations in temperature causes between the epitaxial loayer in the epitaxial process; Another kind is the epitaxial material stress that the gradual change of crystal structure causes in growth course.As shown in Figure 1, be a kind of common situations that in extension Material growth process, occurs, since Sapphire Substrate 21 by with heating base 10 thermal contact conductances, epitaxial loayer 22 warping phenomenons that caused by stress can make the heating-up temperature of Sapphire Substrate 21 inhomogeneous, and the more large-sized Sapphire Substrate 21 of employing, epitaxial loayer 22 material homogeneities of growth are also just poorer, greatly limited the output yield of large scale epitaxial substrate.In addition, epitaxial wafer is in larger stress state and causes easily the epitaxial wafer in the substrate thinning process to break, thereby affects the output yield of follow-up chip technology processing procedure.The method of therefore, epitaxial growth low-stress material is the key technology that GaN base LED makes.

Prior art, the method of knowing in the industry is on sapphire substrate, temporary transient resilient coating at low-temperature epitaxy GaN or AlN, the mitigation that the resilient coating of low-temperature epitaxy can allow lattice deformation become, and then on resilient coating the GaN based semiconductor material of growing high-quality, such as published Japan Patent JP2000124499 and JP7312350.Published Chinese patent CN1123937C has proposed to form respectively the close gallium nitride film layer of a thickness at the sapphire substrate upper and lower surface, can allow the stress of up and down gallium nitride film layer formation cancel each other, thus the possibility that can prevent Sapphire Substrate to break.But said method need to increase epitaxially grown complexity at Sapphire Substrate upper and lower surface difference extension GaN material, simultaneously production cost is increased suddenly.

Summary of the invention

The deficiency that exists in order to overcome above-mentioned prior art the purpose of this invention is to provide a kind of light emitting diode construction that can eliminate stress and preparation method thereof.It can reduce the stress that produces in the GaN base LED material epitaxy growth course, improves the uniformity of GaN base LED epitaxial material and the output yield of GaN base LED chip, is conducive to the further expansion of epitaxial substrate size.

In order to reach the foregoing invention purpose, technical scheme of the present invention realizes as follows:

A kind of light emitting diode construction that can eliminate stress, it comprises Sapphire Substrate and the epitaxial loayer that places on the Sapphire Substrate.Its design feature is that described Sapphire Substrate inside is formed with crisscross cutting cut.

A kind of manufacture method of the light emitting diode construction that can eliminate stress, its step is:

1. use laser that Sapphire Substrate is carried out stealthy cutting technique and process, at the crisscross cutting cut of the inner formation of Sapphire Substrate;

2. the upper surface in the Sapphire Substrate of processing through stealthy cutting technique forms epitaxial loayer.

In above-mentioned manufacture method, the position of described cutting cut can be for along led chip scribe line position or other positions.

The present invention is owing to adopted said structure and method, adopt the stealthy cutting technique of laser Sapphire Substrate to be carried out the stealth cutting in advance, on the process Sapphire Substrate of stealthy cutting technique, prepare GaN base LED epitaxial film materials by the MOCVD technology again, can eliminate the stress that produces in the GaN base LED material epitaxy growth course, improved the uniformity of GaN base LED epitaxial material, promote the output yield of GaN base LED chip, provide the basis for further enlarging the epitaxial substrate size.

The invention will be further described below in conjunction with the drawings and specific embodiments.

Description of drawings

Fig. 1 is in the prior art because the epitaxial loayer warping phenomenon that membrane stress causes;

Fig. 2 is the vertical section structure schematic diagram of the embodiment of the invention one light-emitting diode;

Fig. 3 is the cross section plan structure schematic diagram of Sapphire Substrate in the embodiment of the invention one;

Fig. 4 is the cross section plan structure schematic diagram of Sapphire Substrate in the embodiment of the invention two.

Embodiment

Referring to Fig. 2 and Fig. 3, the present invention includes Sapphire Substrate 21 and the epitaxial loayer 22 that places on the Sapphire Substrate 21.Sapphire Substrate 21 inside are formed with crisscross cutting cut 23, and the position of cutting cut 23 is exactly the scribe line position of led chip.Wherein epitaxial loayer 22 comprises single structure or the composite construction of one or more compositions among gallium nitride GaN, aluminium nitride AlN, InGaN InGaN, aluminium gallium nitride alloy AlGaN, indium nitride InN, the aluminum indium gallium nitride InAlGaN.

The manufacture method step of light-emitting diode of the present invention is:

1. use laser that Sapphire Substrate 21 is carried out stealthy cutting technique and process, at the crisscross cutting cut 23 of Sapphire Substrate 21 inner formation; The position of cutting cut 23 can be for along led chip scribe line position or other positions.

2. the upper surface in the Sapphire Substrate 21 of processing through stealthy cutting technique forms epitaxial loayer 22.

In the above-mentioned manufacture method degree of depth, shape etc. of cutting cut 23 can be by the laser energy size of the stealthy cutting technique of laser, assemble the parameters such as position, cutting speed and control.

Fig. 4 is the Sapphire Substrate 21 in the embodiment of the invention two, and for identical quarter, the position of cutting cut 23 was not the scribe line position of led chip to the inner cutting cuts 23 that form of Sapphire Substrate 21 with whole Sapphire Substrate 21 minutes.

Above-described specific embodiment; purpose of the present invention, technical scheme and beneficial effect have been carried out further detailed description; the above only is specific embodiments of the invention; be not limited to the present invention; all within technical thought of the present invention; the technical scheme that any modification of making, replacement or improvement form all should be included within protection scope of the present invention.

Claims

1. light emitting diode construction that can eliminate stress, it comprises Sapphire Substrate (21) and places epitaxial loayer (22) on the Sapphire Substrate (21), it is characterized in that described Sapphire Substrate (21) inside is formed with crisscross cutting cut (23).

2. the manufacture method of the light emitting diode construction that can eliminate stress, its step is:

1. use laser that Sapphire Substrate (21) is carried out stealthy cutting technique and process, at the crisscross cutting cut (23) of the inner formation of Sapphire Substrate (21);

2. the upper surface in the Sapphire Substrate (21) of processing through stealthy cutting technique forms epitaxial loayer (22).

3. manufacture method according to claim 2 is characterized in that, the position of described cutting cut (23) can be for along led chip scribe line position or other positions.