KR100618086B1 - Method for manufacturing semiconductor device and light emitting diode by using the said method - Google Patents

Abstract

The present invention relates to a semiconductor light emitting device manufacturing method and a light emitting diode using the method. The method of manufacturing a semiconductor light emitting device includes (a) forming a sacrificial film on a surface of a substrate for fabricating a semiconductor light emitting device, (b) forming a metal thin film on the sacrificial film, and (c) predetermined results. Converting the metal thin film into a plurality of irregular metal particle agglomerates by heat treatment for a predetermined time at a temperature of (d) and etching and patterning a sacrificial film formed on the surface of the substrate using the metal particle agglomerates as a mask; (e) etching the surface of the substrate using the patterned sacrificial layer as a mask to form irregularities on the surface of the substrate, and (f) removing the sacrificial layer and the metal particle agglomerates. The time and temperature of the heat treatment in the step (c) of the method for manufacturing a semiconductor light emitting device having the above-mentioned characteristics are determined according to the type of metal forming the metal thin film, and the metal thin film of the step (b) is Au, Pt, Al , Ag, Cu, Sn, Zn, In is preferred.

According to the present invention, minute irregularities may be irregularly formed on the surface of the sapphire substrate without a photolithography process.

Sapphire Board, Light Emitting Diode, Luminance

Description

Method for manufacturing semiconductor device and light emitting diode by using the said method

1 is a cross-sectional view sequentially illustrating a method of manufacturing a semiconductor device in accordance with a preferred embodiment of the present invention.

FIG. 2 is SEM images of a surface in which a plurality of metal particles are irregularly formed by heat treating a metal thin film by a semiconductor device manufacturing method according to a preferred embodiment of the present invention.

3 is a SEM photograph exemplarily showing a shape of an uneven portion formed on a surface of a substrate using a photolithography process.

4 is a SEM image of the vertical direction with respect to the surface of the sapphire substrate formed with irregular irregularities by the semiconductor device manufacturing method according to a preferred embodiment of the present invention.

FIG. 5 is an SEM photograph of the 45-degree direction of the surface of the sapphire substrate having irregular irregularities of FIG.

FIG. 6 is a SEM photograph of a surface in which an oxide film is selectively etched to leave an oxide film residue in a method of manufacturing a semiconductor device according to another exemplary embodiment of the present invention.

<Explanation of symbols for the main parts of the drawings>

100: sapphire substrate

102, 104: Sacrifice

106: metal thin film

110: uneven portion

The present invention relates to a method of manufacturing a semiconductor light emitting device for forming an uneven portion on a sapphire substrate, and to a light emitting diode manufactured using the above method. More specifically, fine uneven portions are formed on a sapphire substrate using a metal thin film without a photolithography process. A method of manufacturing a semiconductor light emitting device and a method of manufacturing a semiconductor light emitting device include a light emitting diode having improved luminance by being manufactured using a substrate having irregular irregularities formed on a surface thereof.

A light emitting diode is an optical device that generates light when a forward current flows. A light emitting diode is fabricated using a structure in which indium phosphorus (InP), gallium arsenide (GaAs), gallium phosphorus (GaP), or gallium nitride (GaN) compound semiconductors are pn bonded, and emit red and green light. Next to the light emitting diodes, light emitting diodes emitting blue and ultraviolet light have been developed. Such light emitting diodes are widely used in display devices, light source devices, and environmental application devices. Recently, white light emitting diodes that emit white light using three chips of red, green, and blue, or phosphors have been developed, and are also applied to lighting. The range is getting wider.

In general, blue or green light emitting diodes are fabricated using PN junctions of gallium nitride based single crystal thin films. However, in the case of using a nitride-based light emitting material such as gallium nitride as the thin film structure in the light emitting diode, a sapphire substrate having a similar lattice constant and crystal structure is used to reduce the occurrence of crystal defects during epitaxial growth. Therefore, in order to fabricate a blue or green light emitting diode, a gallium nitride based single crystal film is grown on a SiC, Al ₂ O ₃ single crystal wafer at a high temperature.

On the other hand, the light emitting diode emits light when the light generated in the active layer of the gallium nitride film formed on the substrate passes through the gallium nitride film and radiates to the outside, and only some of the generated light is not emitted to the outside. It passes through the gallium nitride film and is released to the outside, and the rest is absorbed into the inside.

Generally, inside the light emitting diode, a total reflection angle is caused by a difference between the refractive index of the gallium nitride film (n = 2.2) and the molding resin material (n = 1.5), or a difference between the refractive index of the gallium nitride film and the refractive index of the sapphire substrate (n = 1.8). Will be produced. The light emitted at an angle equal to or greater than the total reflection angle causes total reflection at the interface between the gallium nitride film and other materials, thereby repeatedly reflecting to the inside and is eventually absorbed and extinguished. Therefore, in order to reduce the light disappearing inside the light emitting diode and increase the external emission efficiency of the light to improve the brightness of the light emitting diode, many methods of scattering light by forming a plurality of irregularities at the interface of the gallium nitride film Is being studied.

In general, a method of forming an uneven portion at an interface of a gallium nitride film is performed by forming an uneven portion on a sapphire substrate, forming an uneven portion on a P-doped gallium nitride film, or N-doped nitride film during a thin film process on a gallium nitride film. It can be divided into a method of forming the uneven portion.

Among these methods, in order to form the uneven portion on the sapphire substrate, conventionally a method using a photolithography process has been proposed. In the method of forming the uneven portion using the photolithography process, first, a pattern is formed on a sapphire substrate using a photosensitive film, and then dry etching using plasma is performed on the surface of the sapphire substrate by using a pattern formed as a mask. Uneven portion is formed. In order to form such minute sized irregularities on the sapphire substrate, not only a photolithography technique that supports high-precision fine patterning but also a dry etching apparatus having a high output performance of 1 kW or more is required. In addition, in order to form a fine pattern of several hundred nm size to be used as a mask on the sapphire substrate, expensive and precise exposure equipment such as a stepper is required, rather than a conventional contact type exposure machine.

As such, in order to form fine uneven parts on the sapphire substrate by using a photolithography process according to the conventional method, expensive precise exposure equipment and expensive high power etching equipment are required, and sophisticated technology for fine patterning is required. In fact, there is a problem inherent in the production line that is not easy to implement.

Accordingly, the present applicant intends to propose a method for forming a fine concavo-convex portion on the sapphire substrate without a patterning process using a photolithography process.

An object of the present invention for solving the above problems is to provide a method of manufacturing a semiconductor light emitting device for forming a fine concave-convex portion on the sapphire substrate, without the patterning process using a photolithography process.

Another object of the present invention is to provide a method of manufacturing a semiconductor light emitting device that forms minute uneven portions on a sapphire substrate using a metal thin film.

Still another object of the present invention is to provide a method of manufacturing a semiconductor light emitting device for forming fine uneven parts on a sapphire substrate using an selectively etched oxide film.

Still another object of the present invention is to provide a light emitting diode manufactured by using a sapphire substrate having fine uneven portions formed on the surface by the method of manufacturing a semiconductor light emitting device described above.

A feature of the present invention for achieving the above-described technical problem relates to a method of manufacturing a semiconductor light emitting device for forming minute uneven portions on the surface of the substrate without a photolithography process,

(a) forming a sacrificial film on a surface of a substrate for manufacturing a semiconductor light emitting device,

(b) forming a metal thin film on the sacrificial film,

(c) heat treating the resultant at a predetermined temperature for a predetermined time to convert the thin metal film into a plurality of irregular lumps of metal particles;

(d) etching and patterning the sacrificial film formed on the surface of the substrate using the metal particles as a mask;

(e) etching the surface of the substrate using the patterned sacrificial layer as a mask to form irregularities on the surface of the substrate, and

(f) removing the sacrificial film and the metal particle agglomerates.

The time and temperature of the heat treatment in step (c) of the method for manufacturing a semiconductor device having the above-described characteristics are determined according to the type of metal forming the metal thin film, and the metal thin film of step (b) is Au, Pt, Al, It is preferable that it is one of Ag, Cu, Sn, Zn, In.

A semiconductor device manufacturing method according to another feature of the present invention,

(a) forming a sacrificial film on the surface of the substrate,

(b) forming an oxide film on the sacrificial film,

(c) selectively etching the oxide layer through wet etching to form an island-shaped residue on a surface thereof;

(d) patterning a sacrificial film formed on the surface of the substrate using the oxide residue as a mask;

(e) etching the surface of the substrate using the patterned sacrificial layer as a mask to form an uneven portion on the surface of the substrate.

According to another aspect of the present invention, a light emitting diode is fabricated on a substrate on which irregularities are irregularly formed on a surface by the semiconductor device manufacturing method described above to improve brightness.

Hereinafter, a method of manufacturing a semiconductor device according to an exemplary embodiment of the present invention will be described in detail with reference to the accompanying drawings.

1A to 1F are cross-sectional views sequentially illustrating a process of forming fine uneven parts on the surface of a sapphire substrate by a semiconductor device manufacturing method according to an exemplary embodiment of the present invention.

As shown in (a) and (b) of FIG. 1, first, a sacrificial film 104 is formed on the surface of the sapphire substrate 100 on which the uneven portion is to be formed. The sacrificial film 104 is formed by depositing a silicon oxide film or a silicon nitride film on a sapphire substrate.

In another embodiment of the present invention, the sacrificial film is formed not only on the upper surface of the sapphire substrate but also on the lower surface thereof to prevent the lower surface of the sapphire substrate from being etched during the processing.

Next, a metal thin film 106 is coated on the sacrificial film 104. At this time, the metal thin film may be formed as one of the metals such as Au, Pt, Al, Ag, Cu, Sn, Zn, In, in addition, if the metal that can form agglomerates of metal particles by appropriate heat treatment, of course the metal It can be used as a material of the thin film.

In addition, the temperature and time of the heat treatment is determined differently depending on the type of metal, and when using gold (Au) it is preferable to heat treatment for about 1 minute at about 700 ° ~ 900 ° Celsius. The melting point of Au is about 1064 degrees Celsius. Thin films actually form agglomerates of metal particles at about 700 ° to 900 °. FIG. 2 (a) is a SEM photograph of the surface of a gold thin film having a thickness of 40 GPa at 800 °, and FIG. 2 (b) is a heat treatment of a gold thin film having a thickness of 40 GPa at 900 °. SEM picture of the surface of the. From the photographs of FIG. 2, it can be seen that agglomerates of finely-sized metal particles are irregularly formed on the sapphire substrate.

Next, as shown in FIG. 1C, by heat-treating the sapphire substrate 100 on which the metal thin film and the sacrificial film are formed, the metal thin film is melted, and the molten metal particles are localized to adjacent metal particles by surface tension. By agglomerating with each other, many fine metal particles 108 are formed on the surface of the sacrificial film.

Next, as shown in FIG. 1D, the sacrificial film 104 is etched and patterned using the fine metal particle agglomerates 108 formed on the sacrificial film 104 as a mask. In this case, the sacrificial layer 104 is patterned by dry etching or wet etching.

Next, as shown in (e) of FIG. 1, the sapphire substrate having the metal particle mass 108 and the patterned sacrificial film 104 is immersed in a high temperature sulfuric acid solution for a predetermined time or more. The sapphire substrate 100 is selectively wet-etched using the 108 and the patterned sacrificial layer 104 as a mask. As a result, minute uneven parts 110 are irregularly formed on the surface of the sapphire substrate 100. In another embodiment of the present invention, in order to wet etch the sapphire substrate, an acid mixture may be used in addition to sulfuric acid having a high temperature (about 100 degrees Celsius or more).

Next, as shown in (f) of FIG. 1, by removing the metal particle lumps 108 and the patterned sacrificial film 104 on the surface of the sapphire substrate where the minute uneven portions 110 are irregularly formed, It is possible to obtain a sapphire substrate 100 in which minute irregularities are irregularly formed.

At this time, the metal particles are removed by wet etching, and the etchant is determined according to the type of each metal. For example, gold (Au) is etched with a strong acid (generally called aqua regia) mixed with hydrochloric acid and nitric acid in a 3: 1 ratio, while aluminum (Al) is etched with a hydrochloric acid or strong base solution. .

In addition, the silicon oxide film or nitride film used as the sacrificial film is removed by wet etching using hydrofluoric acid (HF). The sacrificial film formed on the lower surface of the sapphire substrate prevents the back side of the substrate from being etched during the high temperature sulfuric acid etching.

The size of the uneven portion formed by the present invention is about 0.5㎛ or less in diameter, the height of the uneven portion is about 150 nm or more, the overall shape of the uneven portion is a triangular pyramid shape. At this time, the height of the uneven portion formed on the surface of the sapphire substrate may be determined according to the wet etching degree of the sapphire substrate. That is, since the longer the etching time, the longer the etching time tends to be deeply etched, so that the longer the etching time, the higher the height of the uneven portion is.

In addition, the shape of the uneven portion may be modified according to the etching method and the etching degree of the sapphire substrate. 3 is a photograph for exemplarily illustrating a shape of an uneven part according to an etching solution, and shows an example of an uneven part formed by etching with a specific etching solution using a photolithography process. 3A and 3B are SEM photographs exemplarily illustrating the shape of the uneven parts of the etching solution. Figure 3 (a) is a photograph of the surface of the sapphire substrate etched using a high temperature sulfuric acid solution, the overall has a shape that is close to a triangle having a direction, the upper portion is a circular shape, the triangle toward the etched lower portion It can be seen that the shape. Figure 3 (b) is concave etching using a sulfuric acid solution, it can be seen that the etched portion is made in the shape of an inverted triangular pyramid. As such, when the sulfuric acid solution is used, anisotropic etching is performed, and the size and shape of the uneven portion are changed according to the size and shape of the remaining sacrificial film.

According to a preferred embodiment of the present invention described above, it is possible to form minute uneven portions of less than 1 ㎛ on the surface of the sapphire substrate without using a fine photographic etching process. In addition, according to the present invention, even if there is no high-output etching equipment and expensive exposure equipment, it is possible to easily form minute uneven parts on the surface of the sapphire substrate.

FIG. 4 is an SEM photograph of the surface of the sapphire substrate on which fine irregularities are irregularly formed according to the above-described preferred embodiment, and FIG. 5 is an SEM photograph of the 45 ° direction of the surface of the sapphire substrate of FIG. 4. As shown in Figures 4 and 5, it can be seen that the minute horn-shaped irregularities smaller than 1㎛ in diameter irregularly formed on the surface of the sapphire substrate.

Hereinafter, a method of manufacturing a semiconductor device for forming fine uneven parts on the surface of a sapphire substrate according to another embodiment of the present invention will be described in detail.

The semiconductor device manufacturing method according to the present embodiment also forms fine concavo-convex portions on the surface of the sapphire substrate without using a photolithography process. To form.

First, after forming a sacrificial film on the upper surface of the sapphire substrate, an oxide film is deposited on the sacrificial film. At this time, the sacrificial film is formed by depositing a silicon oxide film or a silicon nitride film on a substrate, the oxide film is Indium-Tin-Oxide (In _(x) Sn _(1-x) O), 0 < = x <= 1) is formed by electron beam deposition on the sacrificial film. At this time, the heat treatment may be further performed after the oxide film is formed. The shape of the oxide film residue in the later step may be changed by the heat treatment step. In another embodiment of the present invention, one of indium oxide, tin oxide, and zinc oxide may be deposited as the oxide film.

Next, by wet etching the oxide film using a sulfuric acid solution for a predetermined time, a portion of the oxide film is selectively etched, and the residue remains in an island shape. FIG. 6 is a photograph of a surface in which an oxide film is selectively etched and irregular residues remain according to the present embodiment.

The sacrificial film is patterned using the remaining oxide film residue as a mask, and the sapphire substrate is etched using the patterned sacrificial film as a mask, thereby forming irregularities on the sapphire substrate.

At this time, the size and shape of the islands are determined according to the formation method or the material of the islands, which are oxide residues, and the distribution and size of the uneven parts to be formed on the surface of the sapphire substrate are determined according to the size and shape of the islands. According to another embodiment of the present invention, islands may be formed by depositing a nitride film instead of the oxide film.

Next, the oxide film residue and the sacrificial film on the surface of the sapphire substrate on which the fine uneven portions are formed are removed.

Therefore, by using the semiconductor device manufacturing method according to the present embodiment, it is possible to irregularly form minute uneven portions on the surface of the sapphire substrate using only the oxide film.

By the above method, a gallium nitride film is deposited on a sapphire substrate irregularly formed with irregular irregularities to form an active layer to fabricate a light emitting diode, whereby light is scattered by the minute irregularities formed on the sapphire substrate. It is possible to improve the luminance.

Although the present invention has been described above with reference to preferred embodiments thereof, this is merely an example and is not intended to limit the present invention, and those skilled in the art do not depart from the essential characteristics of the present invention. It will be appreciated that various modifications and applications which are not illustrated above in the scope are possible. For example, in the embodiment of the present invention, the type of metal forming the metal thin film, the etching method of the sapphire substrate, the shape and size of the uneven portion, etc. may be variously modified to improve the luminance of the light emitting diode. And differences relating to such modifications and applications should be construed as being included in the scope of the invention defined in the appended claims.

According to the present invention, minute irregularities may be irregularly formed on the surface of the sapphire substrate by using a metal thin film and heat treatment. Therefore, the method of manufacturing a semiconductor device according to the present invention forms minute uneven parts without a patterning process through a separate photolithography process.

As a result, the semiconductor device manufacturing method according to the present invention can form minute uneven portions having a diameter of 1 μm or less on the surface of the sapphire substrate without expensive sophisticated exposure equipment and expensive high power etching equipment.

By manufacturing a light emitting diode using a substrate having minute uneven portions formed on its surface by the method of manufacturing a semiconductor device according to the present invention, it is possible to improve the brightness of the light emitting diode.

Claims (10)

(a) forming a sacrificial film on a surface of a substrate for fabricating a semiconductor light emitting device; (b) forming a metal thin film on the sacrificial film; (c) heat treating the resultant at a predetermined temperature for a predetermined time to convert the thin metal film into a plurality of irregular lumps of metal particles; (d) etching and patterning the sacrificial film formed on the surface of the substrate using the metal particles as a mask; (e) etching the surface of the substrate using the patterned sacrificial layer as a mask to form uneven portions on the surface of the substrate; And forming irregular irregularities on the surface of the substrate. The method of claim 1, wherein the manufacturing method of the semiconductor light emitting device further comprises removing the sacrificial film and the metal particles after the step (e). The method of claim 1, wherein the time and temperature of the heat treatment of step (c) are determined according to the type of metal forming the metal thin film. The method of claim 1, wherein the metal thin film of step (b) is one of Au, Pt, Al, Ag, Cu, Sn, Zn, In. delete delete  The method of manufacturing a semiconductor light emitting device according to any one of claims 1 to 4, wherein the substrate is sapphire.  The method of manufacturing a semiconductor light emitting device according to any one of claims 1 to 4, wherein the sacrificial film is a silicon oxide film or a silicon nitride film. The method of manufacturing a semiconductor light emitting device according to any one of claims 1 to 4, wherein the surface of the substrate is etched using a wet etching method. A light emitting diode, which is fabricated on a substrate on which irregular irregularities are formed by the semiconductor light emitting device manufacturing method according to any one of claims 1 to 4.

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