阅读说明：本技术 图案化蓝宝石衬底的制备方法 (Preparation method of patterned sapphire substrate ) 是由 谢丁生 谢红 于 2018-07-26 设计创作，主要内容包括：本发明公开了一种图案化蓝宝石衬底的制备方法,在蓝宝石基片上形成金属铝膜,采用反应离子刻蚀的方法,在蓝宝石基片上形成图案化铝膜,然后通过两步热处理的方式使铝膜进行固相反应,最终生成氧化铝单晶薄膜,从而可以获得最优的用于氮化物外延生长的图形化蓝宝石衬底。不同于通常所采用的对蓝宝石衬底直接进行干法刻蚀或湿法刻蚀,本发明可以提高光刻分辨率,增加蓝宝石衬底光提取率,从而获得最优的用于氮化物外延生长的图形化蓝宝石衬底,显著提高LED发光效率。本发明工艺重复性好,应用前景广阔。(The invention discloses a preparation method of a patterned sapphire substrate, which comprises the steps of forming a metal aluminum film on a sapphire substrate, forming the patterned aluminum film on the sapphire substrate by adopting a reactive ion etching method, and then carrying out solid-phase reaction on the aluminum film by a two-step heat treatment mode to finally generate an aluminum oxide single crystal film, thereby obtaining the optimal patterned sapphire substrate for epitaxial growth of nitride. Different from the method of directly carrying out dry etching or wet etching on the sapphire substrate, the method can improve the photoetching resolution and increase the light extraction rate of the sapphire substrate, thereby obtaining the optimal patterned sapphire substrate for the epitaxial growth of nitride and obviously improving the luminous efficiency of the LED. The invention has good process repeatability and wide application prospect.)

1. A preparation method of a patterned sapphire substrate is characterized by comprising the following steps:

step one, obtaining a sapphire substrate;

forming a metal aluminum film on the surface of the sapphire substrate by adopting a direct-current magnetron sputtering technology;

depositing a mask layer on the surface of the metal aluminum film by adopting a metal organic compound chemical vapor deposition method;

forming a photoresist film on the surface of the mask layer in a spin coating mode, placing the mask plate above the substrate, and performing imaging exposure on the pattern on the mask plate by using an exposure machine;

step five, spraying the developing solution on the photoresist film obtained in the step four, carrying out developing treatment on the photoresist film, and transferring the pattern on the mask plate to the photoresist film;

taking the patterned photoresist film as a mask, and forming a patterned mask layer on the sapphire substrate at the corresponding position of the patterned photoresist film by using a wet etching process or a dry etching process;

step seven, taking the patterned mask layer obtained in the step six as a mask, etching the metal aluminum film by adopting a reactive ion etching technology, and removing the patterned mask layer to obtain a patterned metal aluminum film;

step eight, performing low-temperature heat treatment on the sapphire substrate containing the patterned metal aluminum film obtained in the step seven to oxidize the patterned metal aluminum film into a patterned polycrystalline aluminum oxide film;

and step nine, performing high-temperature heat treatment on the sapphire substrate containing the patterned polycrystalline aluminum oxide film obtained in the step eight to oxidize the patterned polycrystalline aluminum oxide film into a patterned monocrystalline aluminum oxide film.

2. The method of manufacturing a sapphire substrate according to claim 1, wherein: and a step of cleaning the sapphire substrate is also included between the step one and the step two, and sulfuric acid hydrogen peroxide is selected as a cleaning solution.

3. The method of manufacturing a sapphire substrate according to claim 1, wherein: the thickness of the metal aluminum film is 150-180 nm, the thickness of the mask layer is 300-800 nm, and the thickness of the photoresist film is 300-800 nm.

4. The method of manufacturing a sapphire substrate according to claim 1, wherein: the specific method of the fourth step is that under the conditions that the rotating speed is 2500-.

5. The method of manufacturing a sapphire substrate according to claim 4, wherein: the exposure process of the exposure machine comprises primary exposure and secondary exposure, and the exposure time of the primary exposure is the same as that of the secondary exposure.

6. The method of manufacturing a sapphire substrate according to claim 1, wherein: the fifth specific method comprises the steps of dripping the developing solution to the center of the surface of the photoresist film under the conditions that the rotating speed is 300-500 rpm and the rotating speed is kept unchanged, uniformly coating the developing solution on the surface of the photoresist film by utilizing centrifugal force, completing the developing process, and transferring the pattern on the mask plate to the photoresist film.

7. The method of manufacturing a sapphire substrate according to claim 1, wherein: the mask layer is made of silicon dioxide.

8. The method of manufacturing a sapphire substrate according to claim 1, wherein: and the temperature of the low-temperature heat treatment in the step eight is 550 ℃, and the heat treatment time is 24 hours.

9. The method of manufacturing a sapphire substrate according to claim 1, wherein: in the ninth step, the high-temperature heat treatment temperature is 1300 ℃, and the heat treatment time is 24 hours.

Technical Field

The invention relates to the technical field of micro-nano electronic manufacturing, in particular to a preparation method of patterned sapphire.

Background

In recent years, the application field of the light emitting diode is becoming wide, the market demand is expanding, and the light emitting diode is widely applied to the fields of displays, television lighting decoration and illumination. The epitaxial wafer in the led is a core part of the led, and therefore, the development of the epitaxial wafer of the led is receiving much attention.

Sapphire has high mechanical strength, is easy to process and clean, has good thermal stability, and is suitable for a high-temperature growth process, so that most processes adopt sapphire as a substrate of an epitaxial wafer, but the sapphire substrate has low light extraction rate on a light-emitting diode due to the structural limitation of the sapphire substrate. The patterned sapphire substrate can relieve stress caused by lattice constant mismatch and thermal expansion coefficient mismatch existing between the nitride epitaxial film and the sapphire substrate, and the linear dislocation density in the nitride epitaxial film is effectively reduced.

The patterned sapphire is generally manufactured by adopting a photoetching technology, and the principle of the patterned sapphire is that a photoresist sensitive to light is coated on the surface of a substrate, a layer of thin film is formed on the surface, then a photoetching plate is used, the photoetching plate contains the graphic information of a specific layer to be manufactured, a light source irradiates the photoresist through the photoetching plate, the photoresist is selectively exposed, then the photoresist is developed, and the transfer of the pattern on the photoetching plate is completed. The resolution refers to the minimum characteristic dimension which can be accurately transferred to the photoresist on the surface of the substrate, and is an important system index in the optical lithography technology, and the improvement of the resolution of the optical lithography is important for improving the quality of the optical lithography.

Disclosure of Invention

The invention aims to solve the technical problem of providing a method for preparing a patterned sapphire substrate, which can solve the problems of low photoetching resolution and low light extraction rate of the sapphire substrate in the prior art.

In order to solve the problems, the invention adopts the following technical scheme:

the invention provides a preparation method of a patterned sapphire substrate, which comprises the following steps:

step one, obtaining a sapphire substrate;

forming a metal aluminum film on the surface of the sapphire substrate by adopting a direct-current magnetron sputtering technology;

depositing a mask layer on the surface of the metal aluminum film by adopting a metal organic compound chemical vapor deposition method;

forming a photoresist film on the surface of the mask layer in a spin coating mode, placing the mask plate above the substrate, and performing imaging exposure on the pattern on the mask plate by using an exposure machine;

spraying a developing solution on the photoresist film obtained in the fourth step, carrying out developing treatment on the photoresist film, and transferring the pattern on the mask plate to the photoresist film;

taking the patterned photoresist film as a mask, and forming a patterned mask layer on the sapphire substrate at the corresponding position of the patterned photoresist film by using a wet etching process or a dry etching process;

removing the patterned photoresist film, etching the metal aluminum film by using the patterned mask layer obtained in the sixth step as a mask and adopting a reactive ion etching technology, and removing the patterned mask layer to obtain a patterned metal aluminum film;

step eight, performing low-temperature heat treatment on the sapphire substrate containing the patterned metal aluminum film obtained in the step seven to oxidize the patterned metal aluminum film into a patterned polycrystalline aluminum oxide film;

and step nine, performing high-temperature heat treatment on the sapphire substrate containing the patterned polycrystalline aluminum oxide film obtained in the step eight to oxidize the patterned polycrystalline aluminum oxide film into a patterned monocrystalline aluminum oxide film.

Furthermore, a step of cleaning the sapphire substrate is further included between the first step and the second step, and a cleaning solution is sulfuric acid hydrogen peroxide.

Furthermore, the thickness of the metal aluminum film is 150-180 nm, the thickness of the mask layer is 300-800 nm, and the thickness of the photoresist film is 300-800 nm.

Further, the specific method of the fourth step is to drop the liquid photoresist to the center of the surface of the mask layer under the conditions that the rotation speed is 2500-.

Further, the exposure process of the exposure machine comprises a primary exposure and a secondary exposure, and the exposure time of the primary exposure and the exposure time of the secondary exposure are the same.

Furthermore, the fifth specific method is to drop the developing solution to the center of the surface of the photoresist film under the conditions that the rotation speed is 300-.

Furthermore, the material of the mask layer is silicon dioxide.

Furthermore, the temperature of the low-temperature heat treatment in the step eight is 550 ℃, and the heat treatment time is 24 hours.

Furthermore, in the ninth step, the high temperature heat treatment temperature is 1300 ℃, and the heat treatment time is 24 hours.

The preparation method of the patterned sapphire substrate adopts a reactive ion etching method, is different from the method of directly carrying out dry etching or wet etching on the sapphire substrate, and forms a patterned metal aluminum film on the sapphire substrate, and then carries out solid-phase reaction on the aluminum film in a two-step heat treatment mode to finally generate an aluminum oxide single crystal film, thereby obtaining the optimal patterned sapphire substrate for epitaxial growth of nitride. Meanwhile, the invention ensures the uniformity of the photoresist film, improves the developing effect of the photoresist film, improves the level of exposure precision, and has good process repeatability and wide application prospect by a rotary gluing mode.

Drawings

The invention is described in further detail below with reference to specific embodiments and with reference to the following drawings.

FIG. 1 is a flow chart of a process for preparing a sapphire substrate of the present invention;

FIG. 2 is a schematic structural diagram of a sapphire substrate with a metallic aluminum film thereon according to the present invention;

FIG. 3 is a schematic structural diagram of a sapphire substrate with a mask layer according to the present invention;

FIG. 4 is a schematic view of a structure of a sapphire substrate with a photoresist film thereon according to the present invention;

FIG. 5 is a schematic view of a sapphire substrate with a patterned photoresist film thereon according to the present invention;

fig. 6 is a schematic structural diagram of a patterned sapphire substrate of the present invention.

Wherein the reference numerals are specified as follows: sapphire substrate 1, metallic aluminum membrane 2, mask layer 3, photoresist film 4.

Detailed Description

As shown in fig. 1, a method for preparing a patterned sapphire substrate includes the following steps:

step one, a sapphire substrate 1 is obtained, the sapphire substrate 1 is cleaned, and sulfuric acid hydrogen peroxide is selected as a cleaning solution.

And step two, forming a metal aluminum film 2 on the surface of the sapphire substrate 1 by adopting a direct-current magnetron sputtering technology, wherein the thickness of the metal aluminum film 2 is 160 nanometers. The resulting structure is shown in fig. 2.

And thirdly, depositing a mask layer 3 on the surface of the metal aluminum film 2 by adopting a metal organic compound chemical vapor deposition method, wherein the mask layer 3 is made of silicon dioxide, and the thickness of the mask layer 3 is 500 nanometers. The resulting structure is shown in fig. 3.

And step four, forming a photoresist film 4 on the surface of the mask layer 3 by adopting a spin coating mode, wherein the thickness of the photoresist film 4 is 500 nanometers. The specific method comprises the following steps: under the conditions that the rotating speed is 3500 rpm and the rotating speed is kept unchanged, the liquid photoresist is dripped to the center of the surface of the mask layer 3, the photoresist is uniformly coated on the surface of the mask layer 3 by utilizing centrifugal force, and the photoresist is baked at 95 ℃ to form the photoresist film 4. The resulting structure is shown in fig. 4.

And arranging a mask plate above the sapphire substrate, projecting the pattern on the mask plate onto the photoresist film 4, and exposing the pattern on the mask plate by using an exposure machine. The exposure process of the exposure machine comprises a primary exposure and a secondary exposure, and the exposure time of the primary exposure is the same as that of the secondary exposure.

And step five, spraying the developing solution on the photoresist film 4 in the step four, carrying out developing treatment on the photoresist film 4, and transferring the pattern on the mask plate to the photoresist film 4. The specific method comprises the following steps: under the conditions that the rotating speed is 400 rpm and the rotating speed is kept unchanged, the developing solution is dripped to the center of the surface of the photoresist film 4, the developing solution is uniformly coated on the surface of the photoresist film 4 by utilizing the centrifugal force, and the pattern on the mask is transferred to the photoresist film 4.

And step six, forming the patterned mask layer 3 on the sapphire substrate at the position corresponding to the patterned photoresist film 4 by using the patterned photoresist film 4 as a mask and utilizing a wet etching process or a dry etching process. The resulting structure is shown in fig. 5.

And step seven, removing the patterned photoresist film 4, etching the metal aluminum film 2 by adopting a reactive ion etching technology by taking the patterned mask layer 3 obtained in the step six as a mask, and removing the patterned mask layer 3 to obtain the patterned metal aluminum film 2. The structure is shown in fig. 6.

And step eight, performing low-temperature heat treatment on the sapphire substrate 1 containing the patterned metal aluminum film 2 obtained in the step seven, wherein the temperature of the low-temperature heat treatment is 550 ℃, and the heat treatment time is 24 hours, so that the patterned metal aluminum film 2 is oxidized into a patterned polycrystalline aluminum oxide film.

And step nine, performing high-temperature heat treatment on the sapphire substrate 1 containing the patterned polycrystalline alumina film obtained in the step eight, wherein the high-temperature heat treatment temperature is 1300 ℃, and the heat treatment time is 24 hours, so that the patterned polycrystalline alumina film is oxidized into the patterned monocrystalline alumina film.

By adopting the method, the finished product of the patterned sapphire substrate is obtained.

The present invention has been described in terms of specific examples, which are provided to aid understanding of the invention and are not intended to be limiting. For a person skilled in the art to which the invention pertains, several simple deductions, modifications or substitutions may be made according to the idea of the invention.