CN102263175A

CN102263175A - LED (light-emitting diode) substrate and manufacturing method thereof

Info

Publication number: CN102263175A
Application number: CN2010101914721A
Authority: CN
Inventors: 高福宝
Original assignee: Beijing North Microelectronics Co Ltd
Current assignee: Beijing North Microelectronics Co Ltd
Priority date: 2010-05-26
Filing date: 2010-05-26
Publication date: 2011-11-30

Abstract

The invention discloses an LED (light-emitting diode) substrate and a manufacturing method thereof, relating to the technical field of semiconductors and being used for simplifying the manufacturing process of a patterning substrate. The manufacturing method of the LED substrate comprises the following steps: forming a mask layer on a matrix, wherein the mask layer is a thin film with a wurtzite structure; and using a wet etching method to etch the mask layer and the matrix until the mask layer is corroded completely, wherein an irregular structure is formed on the surface of the LED substrate. The LED substrate and the manufacturing method thereof can be applied to the process of manufacturing a GaN-based LED device.

Description

LED substrate and preparation method thereof

Technical field

The present invention relates to field of semiconductor technology, relate in particular to a kind of LED (light-emitting diode) substrate and preparation method thereof.

Background technology

At present, the basic LED of GaN (gallium nitride) (Light Emitting Diode, light-emitting diode) internal quantum efficiency generally can reach more than 70%, but, therefore directly have influence on the whole light extraction efficiency of GaN base LED because it is relatively low to be grown in the extraction efficiency (external quantum efficiency) of the GaN base LED on the Sapphire Substrate.

At this problem, have following improvement project in the prior art: at first, on the Sapphire Substrate of GaN base LED by certain etching technics prepare patterned substrate (Patterned SapphireSubstrates, PSS); Then, after the image conversion substrate preparation was finished, growth GaN material made vertical extension of GaN material become horizontal extension thereon.

Particularly, in conjunction with shown in Figure 1, the process of preparation patterned substrate can realize in the following way in the above-mentioned improvement project:

1) mask 102 that the growth dry etching is used on sapphire substrates 101;

2) utilize the photoetching process of standard on described mask 102, to etch required figure;

3) utilize ICP (Inductively Coupled Plasma, inductively coupled plasma) lithographic technique that described sapphire substrates 101 is carried out etching;

4) remove the mask 102 of remainder, thereby obtain having the Sapphire Substrate of certain figure.

State in realization in the preparation process of patterned substrate, the inventor finds that there are the following problems at least in the prior art:

In above-mentioned patterned substrate preparation process, need to use photoetching process and dry carving technology, not only improved producting process difficulty, technology stability is had bigger influence; And owing to need use mask aligner and dry etching equipment, make LED apparatus for production line costliness, increased the manufacturing cost of GaN base LED device.

Summary of the invention

The invention provides a kind of LED substrate and preparation method thereof, in order to the preparation process of graphic simplicity substrate.

For achieving the above object, the present invention adopts following technical scheme:

A kind of preparation method of LED substrate comprises:

Form mask layer on matrix, this mask layer is the film of wurtzite structure;

Utilize wet etching that described mask layer and described matrix are carried out etching, erode fully until described mask layer, described LED substrate surface forms irregular structure.

A kind of LED substrate that utilizes method for preparing, wherein, described LED substrate surface is an irregular structure.

LED substrate provided by the invention and preparation method thereof at first forms the mask layer of wurtzite structure, so that can control etch rate and etching direction well in the subsequent etching process on matrix; Secondly, the etching of finishing described mask layer and matrix by wet etching need not to use photoetching process to form patterned substrate, has reduced producting process difficulty.In the present invention, because described mask layer has adopted the film of wurtzite structure, its inner crystal structure can make etchant solution different to the corrosion rate of corrosion on different crystal orientations of described film; When etchant solution touched described matrix surperficial, the matrix surface that firstly appears out from can be corroded earlier, after all mask layers are corroded fully, will be formed with irregular graphical pattern on the surface of described matrix like this.Compared with prior art, the scheme that provides in the embodiment of the invention not only can obtain comparatively evenly, the reliable patterned substrate of technology, has also simplified the preparation process of patterned substrate simultaneously.

Description of drawings

In order to be illustrated more clearly in the embodiment of the invention or technical scheme of the prior art, the accompanying drawing of required use is done to introduce simply in will describing embodiment below, apparently, accompanying drawing in describing below only is some embodiments of the present invention, for those of ordinary skills, under the prerequisite of not paying creative work, can also obtain other accompanying drawing according to these accompanying drawings.

Fig. 1 is the Principle of Process figure of preparation patterned substrate in the prior art;

Fig. 2 is the method flow diagram of LED substrate etching in the embodiment of the invention;

Fig. 3 is the principle schematic of LED substrate etching process in the embodiment of the invention.

Embodiment

Below in conjunction with the accompanying drawing in the embodiment of the invention, the technical scheme in the embodiment of the invention is clearly and completely described, obviously, described embodiment only is the present invention's part embodiment, rather than whole embodiment.Based on the embodiment among the present invention, those of ordinary skills belong to the scope of protection of the invention not making the every other embodiment that is obtained under the creative work prerequisite.

As shown in Figure 2, the preparation method of the LED substrate that provides in the embodiment of the invention roughly may further comprise the steps:

201, form mask layer on matrix, this mask layer is the film of wurtzite structure.

In the present embodiment, described matrix can be a sapphire substrates;

Simultaneously, in order to control corrosion rate and the corrosion position in the follow-up wet etching process better, described mask layer can preferably adopt the sull of wurtzite structure, for example the zinc oxide ZnO film can be pure ZnO film or ZnO thin film doped (such as zinc oxide aluminum AZO, zinc oxide boron ZO, zinc-gallium oxide GZO etc.) particularly;

In addition, described mask layer can also be some wurtzite structure films such as the aluminium nitride A1N etc. that utilizes other.

202, utilize wet etching that described mask layer and described matrix are carried out etching, erode fully until described mask layer, described LED substrate surface forms irregular structure.

The preparation method of the LED substrate that the embodiment of the invention provides, the etching of finishing described mask layer and matrix by wet etching is to form patterned substrate; Because described mask layer has adopted the film of wurtzite structure, its inner crystal structure can make etchant solution different to the corrosion rate of corrosion on different crystal orientations of described film; When etchant solution touched described matrix surperficial, the matrix surface that firstly appears out from can be corroded earlier, after all mask layers are corroded fully, will form irregular graphical pattern on the surface of described matrix like this.

The preparation method of the LED substrate that the embodiment of the invention is provided below in conjunction with accompanying drawing and instantiation is described in detail.

In conjunction with shown in Figure 3, in the present embodiment, the preparation process of described LED substrate specifically comprises:

At first, on matrix 301 by physical vapour deposition (PVD) (Physical Vapor Deposition, PVD) or chemical vapour deposition (CVD) (Chemical Vapor Deposition, the mask layer 302 of CVD) method deposition one deck wurtzite structure; The thickness of the mask layer of growth is that tens nanometers are to several microns.Particularly, the thickness of described mask layer can cooperate the dimension of picture of regulating substrate with convenient with etchant solution, and its usual thickness is 800nm～1500nm.

In the present embodiment, described mask layer 302 can preferably adopt ZnO film; Further, described ZnO film can be that pure ZnO also can be doping ZnO (as BZO, AZO, GZO etc.), and the effect of doping mainly is to regulate corrosion rate and direction more accurately.

Wherein, physical vapour deposition (PVD) can be methods such as magnetron sputtering or electron beam evaporation, chemical vapour deposition (CVD) can be PECVD (Plasma-Enhanced Chemical Vapor Deposition, the plasma enhanced chemical vapor deposition method) or LPCVD methods such as (Low Pressure Chemical Vapor Deposition, Low Pressure Chemical Vapor Depositions).

The mask layer 302 of growth is the film of wurtzite structure, is example with ZnO, and it is the polycrystalline structure of mono-crystalline structures or edge (002) direction preferential growth, and the polycrystalline structure of this mono-crystalline structures or preferred orientation is dense, and the crystal orientation basically identical; In follow-up process of carrying out wet etching, can be by concentration of regulating etchant solution and corrosion rate and the pattern that etching time is accurately controlled mask layer.

In addition, can also adopt the film of some other wurtzite structure as the film of mask layer, as A1N etc., its purpose all is can erode away irregular as hexahedral hole shape structure for the surface that makes matrix 301.

After growing above-mentioned mask layer 302, use hydrochloric acid, nitric acid to mix with 1: 1 volume ratio, the ionized water of adding up then carries out wet etching as etchant solution to mask layer 302 and matrix 301.In order to control corrosion rate better, in described etchant solution, can also add the doping corrosion inhibiter; This corrosion inhibiter can be a hexamethylenetetramine.

In the present embodiment, the mass concentration of the acid solution in the described etchant solution is below 2%; Preferably, the mass concentration of described acid solution can be controlled between 0.5%～1%.

The consumption that utilizes above-mentioned etchant solution to carry out needed etching time of wet etching and etchant solution all needs the concentration according to etchant solution, the consumption of corrosion inhibiter, and factor is adjusted accordingly to also have thickness, the area of mask layer 302 and whether mix etc.For example, for the mask layer of same thickness, the amount of corrosion inhibiter is many more in the etchant solution, and the time of then carrying out wet etching is just long more; For the thick mask layer of 1 μ m, can etch period be controlled at 1～5 minute by the consumption of regulating corrosion inhibiter.

Still be example with the ZnO film, because ZnO film is a wurtzite structure, the crystal orientation difference of crystals can make corrosion rate also different, so shape structure such as hexagonal structure can appear cheating in film surface in the corrosion process.When etchant solution penetrated mask layer 302 and touches matrix 301 surperficial, the surface of the matrix 301 that firstly appears out from can be corroded earlier; Therefore, the extent of corrosion of zones of different is also different on the surface of described matrix 301.After whole mask layer 302 was corroded fully, matrix 301 surfaces will form irregular graphical pattern.

In the preparation process of above-mentioned LED substrate, used etchant solution is except can being hydrochloric acid, nitric acid (volume ratio is 1: 1) and the deionized water, can also be to use hydrochloric acid, deionized water described mask layer and described matrix to be carried out wet etching, perhaps use chloroazotic acid, deionized water described mask layer and described matrix to be carried out wet etching as etchant solution as etchant solution.Specifically selecting for use which kind of acid solution to prepare described etchant solution can determine according to the mask material that reality adopts.

In the present embodiment, can be used as the sull of mask layer, and utilize the technology of wet etching to come the LED substrate is carried out etching to form patterned substrate by increasing one deck; Owing to can make etchant solution different as the crystal structure of the film inside of the wurtzite structure of mask layer and the difference in crystal orientation, and then have influence on the difference that the degree of being corroded appears in matrix surface to the corrosion rate of corrosion on different crystal orientations of described film; Utilize this point, just can be by regulating thickness, the concentration of etchant solution and the erosion profile that etching time is controlled Sapphire Substrate of mask layer.

In addition, also provide a kind of LED substrate that utilizes method for preparing in the embodiment of the invention, the surface of this LED substrate is an irregular structure.

Because the film of having selected wurtzite structure for use in said method embodiment is as mask layer, so the irregular structure on the LED substrate surface in the embodiment of the invention, can be etched to hexahedron hole shape structure.

The above; only be the specific embodiment of the present invention, but protection scope of the present invention is not limited thereto, anyly is familiar with those skilled in the art in the technical scope that the present invention discloses; the variation that can expect easily or replacement all should be encompassed within protection scope of the present invention.Therefore, protection scope of the present invention should be as the criterion with the protection range of claim.

Claims

1. the preparation method of a LED substrate is characterized in that, comprising:

Form mask layer on matrix, this mask layer is the film of wurtzite structure;

2. the preparation method of LED substrate according to claim 1 is characterized in that, described matrix is a sapphire substrates.

3. the preparation method of LED substrate according to claim 1 is characterized in that, described mask layer is ZnO film or AlN film or ZnO thin film doped.

4. the preparation method of LED substrate according to claim 1 is characterized in that, the described wet etching that utilizes carries out etching to described mask layer and described matrix, specifically comprises:

Use hydrochloric acid, deionized water described mask layer and described matrix to be carried out wet etching as etchant solution.

5. the preparation method of LED substrate according to claim 1 is characterized in that, the described wet etching that utilizes carries out etching to described mask layer and described matrix, specifically comprises:

Use hydrochloric acid, nitric acid and deionized water described mask layer and described matrix to be carried out wet etching as etchant solution;

Wherein, the volume ratio of described hydrochloric acid and nitric acid is 1: 1.

6. the preparation method of LED substrate according to claim 1 is characterized in that, the described wet etching that utilizes carries out etching to described mask layer and described matrix, specifically comprises:

Use chloroazotic acid, deionized water described mask layer and described matrix to be carried out wet etching as etchant solution.

7. according to the preparation method of each described LED substrate in the claim 4 to 6, it is characterized in that described etchant solution also comprises corrosion inhibiter.

8. the preparation method of LED substrate according to claim 7 is characterized in that, described corrosion inhibiter is a hexamethylenetetramine.

9. according to the preparation method of each described LED substrate in the claim 4 to 6, it is characterized in that in described etchant solution, the mass concentration of acid solution is below 2%.

10. the preparation method of LED substrate according to claim 9 is characterized in that, in described etchant solution, the mass concentration of described acid solution is between 0.5%～1%.

11. the preparation method of LED substrate according to claim 1 is characterized in that, the thickness of described mask layer is 800nm～1500nm.

12. a LED substrate that utilizes each described method preparation in the claim 1 to 11 is characterized in that described LED substrate surface is an irregular structure.

13. LED substrate according to claim 12 is characterized in that, described irregular structure is a hexahedron hole shape structure.