TWI459553B - Micro-structure having taper conformation and manufacturing method thereof - Google Patents

Description

Microstructure with tapered structure and manufacturing method thereof

The present invention relates to a microstructure having a tapered structure and a manufacturing method thereof, and more particularly to a microstructure having a special shape structure designed to enhance light extraction efficiency at the top and a manufacturing method thereof.

Existing optoelectronic components, such as light-emitting diodes, light sensors or solar cells, are often subjected to patterning techniques to increase optical performance. For example, a surface of the light-emitting diode or a substrate thereof is patterned to increase the light-emitting efficiency of the light-emitting diode. A patterned microstructure is then formed, for example, on the surface of the photosensor to increase light absorption efficiency. Alternatively, for example, a patterning process is performed on the surface of the solar cell and the patterned layer obtained by performing the process is used as an anti-reflection layer to further increase the flux of photons into the solar cell.

However, existing patterning techniques employ a single etching process. The patterned microstructure formed by the microstructure is not divided into the first portion and the second portion of the transition, and the special shape structure for improving the light efficiency is not designed for the top of each microstructure. In addition, the pitch between adjacent microstructures is larger than the diameter of each microstructure, that is, the space between adjacent microstructures cannot be eliminated. As a result, the coverage of the patterned microstructure in the optoelectronic component is limited. Therefore, the light-emitting efficiency of the photovoltaic element still has considerable room for improvement. All of the above are technical issues still to be solved.

In view of various problems of the prior art, the inventors have proposed a microstructure having a tapered structure and a manufacturing method thereof based on years of research and development and many practical experiences, as an implementation method and basis for improving the above disadvantages.

It is an object of the present invention to provide a microstructure having a tapered structure that greatly enhances the light extraction efficiency of a component or the flux of photons entering a component, and a method of fabricating the same.

Another object of the present invention is to provide a microstructure having a tapered structure that reduces the spacing between adjacent microstructures and a method of fabricating the same.

It is still another object of the present invention to provide an adjustment parameter for performing a second etching operation to control the volume ratio of the first portion and the second portion of the body to further obtain an optimum volume ratio required for design or subsequent component processing. And if the length of time for performing the second etching operation is sufficient, the second portion having a three-sided pyramid shape completely replaces the first portion to form a microstructure having a pyramidal structure and a micro-structure having a triangular structure and a manufacturing method thereof.

According to the above object of the present invention, the present invention provides a microstructure having a tapered structure, comprising a body of a single crystal material, the body comprising a first portion that is three-dimensional and a second portion that is a three-dimensional cone, and the second portion is located Above the first portion, and the first portion and the second portion are connected to each other, the upper edge of the first portion and the lower edge of the second portion have a turning boundary such that the second portion extends from the turning boundary in a direction away from the first portion.

According to the above object of the present invention, the present invention provides a further microjunction having a tapered configuration The method for fabricating the structure comprises the following steps: performing an exposure and development operation on a substrate, a buffer layer or an element whose material is a single crystal material to define at least one microstructure on the substrate, the buffer layer or the component; a dry etching operation for 2 to 120 minutes or a first wet etching operation for 2 to 120 minutes on a substrate, buffer layer or element having a microstructure defined to form a microstructure onto the substrate, buffer layer or component; And performing a second dry etching operation for 1 to 40 minutes or a second wet etching operation for 1 to 40 minutes on the substrate, the buffer layer or the element having formed the body to form a second portion of the solid cone shape on the body. The body includes a first portion and a second portion, and the upper edge of the first portion and the lower edge of the second portion have a turning boundary, and the second portion extends inwardly from the turning boundary in a direction away from the first portion.

The etch rate of different crystal faces of the single crystal material is different, so as to form a second part of the three-dimensional cone shape on the body, the body includes the first part and the second part, that is, the invention is directed to each micro The top of the structure is designed to enhance the special shape of the light efficiency. Therefore, the microstructure having the tapered structure of the present invention can greatly improve the light extraction efficiency of the element or the flux of the photon into the element, and can simultaneously reduce the lattice defects generated by the epitaxial growth and reduce the thermal effect of the element. In addition, the second dry etching operation or the second wet etching operation of the present invention can reduce the interval between adjacent microstructures, that is, the interval between adjacent microstructures can be zero, further improving the microstructure in the component. Coverage, the light extraction efficiency of the components is also improved. In addition, the fabrication method of the present invention can control the volume ratio of the first portion to the second portion of the body by adjusting the relevant parameters for performing the second etching operation to obtain the optimum volume ratio required for the design or subsequent component process. If the second etching operation is performed for a sufficient length of time, until the end, the second portion having a three-dimensional pyramid shape will completely replace the first portion to form a microstructure of the trihedral pyramid.

For a better understanding and understanding of the technical features and the efficacies of the present invention, the preferred embodiments and the detailed description are as follows.

1‧‧‧ Ontology

11‧‧‧Part 1

12‧‧‧ second part

13‧‧‧ Turning junction

2‧‧‧Substrate

3‧‧‧ components

100~500‧‧‧Steps

1 is a schematic view of a preferred embodiment of a microstructure having a tapered structure according to the present invention; and FIG. 2A is a schematic view of a bottom shape of a preferred embodiment of the microstructure having a tapered structure of the present invention; BRIEF DESCRIPTION OF THE DRAWINGS FIG. 2C is a bottom view of a preferred embodiment of a microstructure having a tapered structure; FIG. 2C is a bottom view of a preferred embodiment of a microstructure having a tapered structure; BRIEF DESCRIPTION OF THE DRAWINGS FIG. 4 is a schematic view showing a preferred embodiment of a microstructure having a tapered structure of the present invention, and FIG. 4 is a preferred embodiment of a microstructure having a tapered structure according to the present invention. Figure 5A is a schematic view of the optical path of the tapered structure and the existing patterned microstructure of the present invention; and Figure 5B is the microstructure of the tapered structure of the present invention and the existing photoelectric conversion element FIG. 6 is a schematic view showing the steps of a preferred embodiment of a method for fabricating a microstructure having a tapered structure; 7 is a schematic view showing a second etching operation of the method for fabricating a microstructure having a tapered structure according to the present invention, and FIG. 8 is a schematic view showing a method for fabricating a microstructure having a tapered structure according to the present invention; Atomic force microscopy observation of microstructures formed by different etching time lengths; Fig. 9 is a scanning electron of microstructures formed by different etching time lengths according to the method for fabricating the pyramid structure of the present invention Microscope observation chart; and Fig. 10 is a scanning electron microscope observation view of the microstructure formed by the tapered structure of the present invention, which is formed by different etching time lengths.

Hereinafter, the microstructure of the present invention having a tapered structure and a method of fabricating the same will be described with reference to the related drawings. For ease of understanding, the same elements in the following embodiments are denoted by the same reference numerals.

First, referring to Fig. 1, there is shown a schematic view of a preferred embodiment of the microstructure having a tapered structure of the present invention. The microstructure of the present invention having a tapered configuration includes a body 1. The material of the aforementioned body 1 is a single crystal material. The body 1 includes a first portion 11 and a second portion 12. The second portion 12 is located above the first portion 11, and the first portion 11 and the second portion 12 are connected to each other. A transition junction 13 is formed between the upper edge of the first portion 11 and the lower edge of the second portion 12 such that the second portion 12 extends inwardly from the transition junction 13 in a direction away from the first portion 11. The first portion 11 is three-dimensional. The three-dimensional shape is, for example, a three-dimensional column shape or a three-dimensional cone shape. The second portion 12 is a three-dimensional cone. The three-dimensional tapered shape is, for example, a three-dimensional cone shape or a cube-shaped pyramid shape. The aforementioned single crystal material is, for example, a single crystal material such as sapphire, single crystal germanium or tantalum carbide.

Referring to FIGS. 2A-2C again, it is a schematic diagram showing the bottom shape of a preferred embodiment of the microstructure having a tapered structure of the present invention. As shown in Fig. 2A, the bottom of the body 1 can be circular. As shown in Fig. 2B, the bottom of the body 1 can be square. As shown in Fig. 2C, the bottom of the body 1 may be a regular hexagon. The aforementioned circular, square or regular hexagon is merely an example but not limited. The shape of the bottom of the body 1 can be easily understood by those skilled in the art, and therefore will not be described again.

Referring to FIG. 3 again, it is a schematic view showing a preferred embodiment of the microstructure having a tapered structure of the present invention fabricated on a substrate. The microstructure having the tapered structure of the present invention can be fabricated on the substrate 2. The body 1 fabricated on the substrate 2 can be plural. The space between adjacent bodies 1 is equal to or greater than zero. The substrate 2 is, for example, a single crystal substrate such as a sapphire substrate, a single crystal germanium substrate, or a tantalum carbide substrate.

It should be particularly noted that the microstructure having the tapered structure of the present invention can also be fabricated on the buffer layer of the substrate 2 having the buffer layer [not shown). The body 1 fabricated on the buffer layer may be plural. The space between adjacent bodies 1 is equal to or greater than zero. The substrate 2 is, for example, a sapphire substrate. The buffer layer is, for example, a gallium nitride buffer layer.

Referring to FIG. 4 again, it is a schematic view showing a preferred embodiment of the microstructure having a tapered structure of the present invention fabricated on an element. The microstructure of the present invention having a tapered configuration can be fabricated on the element 3. The body 1 fabricated on the component 3 can be plural. The space between adjacent bodies 1 is equal to or greater than zero. The aforementioned element 3 is, for example, an element such as a light emitting diode element, a light sensing element or a solar cell element.

As described above, the microstructure having the tapered structure of the present invention can be fabricated on the substrate 2, the buffer layer or the element 3. When the microstructure having the tapered structure is formed on the substrate 2 or the buffer layer, the light extraction efficiency of the subsequently fabricated component can be greatly improved, and the external quantum efficiency of the component to be fabricated can be further improved. Moreover, the lattice defects generated by the epitaxial growth can be reduced when the components are to be fabricated by the subsequent fabrication.

When the microstructure having the tapered structure is fabricated on the light-emitting diode element, the light-emitting efficiency of the light-emitting diode element can be greatly improved, the external quantum efficiency of the light-emitting diode element can be further improved, and the light-emitting diode can be reduced. The thermal effect of the polar body components. When the microstructure having the tapered structure is fabricated on the solar cell element, since the microstructure has a second portion which is a three-dimensional pyramid shape, the microstructure having the tapered structure can be used as an anti-reflection layer of the solar cell element. Effectively increase the flux of photons into the solar cell components.

Please refer to FIG. 5A again, which is a schematic diagram showing the optical path of the tapered structure and the existing patterned microstructure of the present invention. The light in the drawing is shown by the arrow in the figure, which is incident from the bottom of the microstructure, and as shown on the left side of the figure, the microstructure having the tapered structure of the present invention has a three-dimensional cone shape. The second portion 12, therefore, has a tapered structure-like microstructure having better damage to total reflection than the prior art patterned microstructure shown to the right of the figure. Moreover, the space of the microstructure having the tapered structure of the present invention can be equal to zero, and therefore, the microstructure having the tapered structure of the present invention can obtain excellent coverage. Accordingly, the microstructure having the tapered structure of the present invention can greatly improve the light extraction efficiency of the element and further enhance the external quantum efficiency of the element.

Referring to FIG. 5B again, it is a schematic diagram showing the optical path of the microstructure having the tapered structure and the existing photoelectric conversion element of the present invention. The light in the picture, as shown As indicated by the arrow in the face, it is incident from the top of the microstructure, and as shown on the left side of the figure, since the microstructure having the tapered structure of the present invention has the second portion 12 which is a three-dimensional pyramid shape, it can be constructed. A progressive refractive index effect is introduced to further effectively introduce light incident from the top thereof into the interior thereof. In contrast, the existing photoelectric conversion element shown on the left side of the drawing has a larger proportion of incident light reflected. Accordingly, it is understood that the microstructure having the tapered structure of the present invention can be applied to a photoelectric conversion element to increase the flux of photons entering the photoelectric conversion element. The aforementioned photoelectric conversion element is, for example, a solar element or a photodetection element.

Please refer to FIG. 6 again, which is a schematic diagram showing the steps of a preferred embodiment of the method for fabricating the microstructure having the tapered structure of the present invention. The method for fabricating the microstructure having the tapered structure of the present invention comprises the following steps: Step 100: performing an exposure and development operation on the substrate, the buffer layer or the component to define at least one microstructure on the substrate, the buffer layer or On the component. The substrate is, for example, a single crystal substrate such as a sapphire substrate, a single crystal germanium substrate or a tantalum carbide substrate. The buffer layer is, for example, a gallium nitride buffer layer. The aforementioned elements are, for example, elements such as light emitting diode elements, light sensing elements or solar cell elements. The aforementioned exposure and development operation can be performed by a stepper.

Step 200: Perform a hard baking action for 1 to 30 minutes on a substrate, buffer layer or component that has defined a microstructure.

Step 300: Perform a cleaning action for 5 to 20 minutes on a substrate, buffer layer or component that has defined a microstructure.

Step 400: performing a first dry etching operation for 2 to 120 minutes or a first wet etching operation for 2 to 120 minutes on a substrate, a buffer layer or an element in which a microstructure has been defined, to form The microstructure is formed on the substrate, buffer layer or component. The first dry etching operation is, for example, ion-coupled plasma reactive ion etching.

Step 500: performing a second dry etching operation for 1 to 40 minutes or a second wet etching operation for 1 to 40 minutes on a substrate, a buffer layer or an element having formed a body, and using an etching rate system of different crystal faces of the single crystal material of the body For the different characteristics, to form a second portion of the three-dimensional cone shape on the body, the body includes the first portion and the second portion, and the upper edge of the first portion and the lower edge of the second portion have a turning boundary. The second portion extends inwardly from the turning junction toward the inner portion away from the first portion. The second dry etching operation is, for example, a dry acid etching operation. The second wet etching operation is, for example, a high temperature wet acid etching operation. The acid etchant used in the dry acid etching operation or the high temperature wet acid etching operation has a temperature between 200 and 400 degrees Celsius, and the ratio of sulfuric acid to phosphoric acid is between 0.1 and 10.

Please refer to FIG. 7 again, which is a schematic diagram showing the interval between the second etching action and the reduced microstructure of the method for fabricating the microstructure having the tapered structure of the present invention. As shown, the microstructure formed by performing the foregoing step 400 is indicated by a broken line; the microstructure formed by the foregoing step 500 is indicated by a solid line. It can be seen that in the case where the pitch between adjacent microstructures is constant, the second dry etching operation or the second wet etching operation is performed to narrow the interval between adjacent microstructures.

Please refer to FIG. 8 again, which shows an atomic force microscope observation of the microstructure formed by the method of manufacturing the microstructure having the tapered structure of the present invention. As shown, the body that is not subjected to the second dry etching operation or the second wet etching operation does not have the second portion that is a three-dimensional tapered shape. On the other hand, the states 1 to 5 in the figure sequentially indicate that the etching time length is gradually increased, and the state of the microstructure having the tapered structure tends to change. As shown, a second dry etch or second wet The etching operation can be formed into a second portion of the three-dimensional cone shape on the body. And the longer the etching operation takes place, the smaller the interval between adjacent microstructures. In addition, as the length of time during which the etching operation is performed is different, the second portion of the three-dimensional pyramid shape is also different. If the second etching operation is performed for a sufficient length of time, until the end, the second portion having a three-dimensional pyramid shape will completely replace the first portion to form a microstructure of the trihedral pyramid.

Please refer to FIG. 9 again, which is a scanning electron microscope observation diagram of the microstructure formed by the method of manufacturing the microstructure having the tapered structure of the present invention. As shown, the spacing of the bodies that are not subjected to the second dry etching operation or the second wet etching operation is quite significant. On the other hand, the states 1 to 5 in the figure sequentially indicate that the etching time length is gradually increased, and the state of the microstructure having the tapered structure tends to change. As shown, the longer the etching operation takes place, the smaller the spacing between adjacent microstructures. Further, as the length of time during which the second etching operation is performed is different, the state of the second portion which is a three-dimensional pyramid shape is also different. If the second etching operation is performed for a sufficient length of time, until the end, the second portion having a three-dimensional pyramid shape will completely replace the first portion to form a microstructure of the trihedral pyramid.

Please refer to FIG. 10 again, which is a scanning electron microscope observation diagram of the microstructure formed by the method of manufacturing the microstructure having the tapered structure of the present invention. As shown, the body that is not subjected to the second dry etching operation or the second wet etching operation does not have the second portion that is a three-dimensional tapered shape. On the other hand, the states 1 to 5 in the figure sequentially indicate that the etching time length is gradually increased, and the state of the microstructure having the tapered structure tends to change. As shown, a second portion of the three-dimensional cone shape can be formed on the body. And the longer the etching operation takes place, the smaller the interval between adjacent microstructures. In addition, as the length of time for performing the second etching operation is different, it is three-dimensional The shape of the second part of the cone is also different.

It should be specially noted that the volume ratio of the first portion to the second portion of the body can be controlled by adjusting the relevant parameters of the second etching operation. In detail, if the temperature and the length of the second etching operation are adjusted, Then, the volume ratio of the first part to the second part of the body can be controlled. For example, the higher the temperature and the longer the time, the smaller the volume ratio of the first portion to the second portion; conversely, the lower the temperature and the shorter the time, the larger the volume ratio of the first portion to the second portion. Further, the above is exemplified by performing secondary etching once, but the secondary etching may be repeated twice, three times, four times or more. The present invention is merely an example of performing secondary etching once, but is not limited thereto.

In summary, the microstructure having the tapered structure of the present invention and the manufacturing method thereof have at least the following advantages:

1. The light-emitting efficiency of the component or the flux of the photon entering the component is greatly improved: the etching rate of the different crystal faces of the single crystal material is different in the present invention, so as to form the second part of the three-dimensional cone shape on the body, the body is The first part and the second part are included, that is, the present invention is designed for the top of each microstructure to have a special shape structure that enhances light efficiency. Therefore, the microstructure having the tapered structure of the present invention can greatly improve the light extraction efficiency of the element or the flux of the photon into the element, and can simultaneously reduce the lattice defects generated by the epitaxial growth and reduce the thermal effect of the element.

2. The spacing between adjacent microstructures is reduced: the second dry etching operation or the second wet etching operation of the present invention can reduce the interval between adjacent microstructures, that is, the interval between adjacent microstructures can be Zero further enhances the coverage of the microstructure in the component, and the light extraction efficiency of the component is also improved.

3. The volume ratio of the first part to the second part can be controlled: if the relevant parameters of the second etching action, such as temperature and time length, are adjusted, the volume ratio of the first part to the second part of the body can be controlled to obtain a design. Or the optimum volume ratio required for subsequent component processes. If the second etching operation is performed for a sufficient length of time, until the end, the second portion having a three-dimensional pyramid shape will completely replace the first portion to form a microstructure of the trihedral pyramid.

The above is intended to be illustrative only and not limiting. Any equivalent modifications or alterations to the spirit and scope of the invention are intended to be included in the scope of the appended claims.

1‧‧‧ Ontology

11‧‧‧Part 1

12‧‧‧ second part

13‧‧‧ Turning junction

Claims (5)

A method for fabricating a microstructure having a tapered structure is formed by performing an exposure developing operation on a substrate, a buffer layer or a component of a single crystal material to define at least one microstructure On the substrate, the buffer layer or the element; performing a first dry etching operation for 2 to 120 minutes or a first wet etching operation for 2 to 120 minutes on the substrate, the buffer layer having defined the microstructure Or the element to form one of the microstructures on the substrate, the buffer layer or the element; and performing a second dry etching operation for 1 to 40 minutes or a second wet etching operation for 1 to 40 minutes Forming the substrate, the buffer layer or the element of the body to form a second portion of the solid cone shape on the body, wherein the body includes a first portion and the second portion, and the first portion A portion of the upper edge and the lower edge of the second portion have a turning boundary, and the second portion extends inwardly from the turning boundary in a direction away from the first portion. The method for fabricating a microstructure having a tapered structure according to claim 1, wherein the exposure and development operation is performed between the first dry etching operation or the first wet etching operation. Bake action 1 to 30 minutes on the substrate, the buffer layer or the element in which the microstructure has been defined; and a cleaning action for 5 to 20 minutes on the substrate, the buffer layer or the defined microstructure The component. The method for fabricating a microstructure having a tapered structure according to claim 1, wherein the first dry etching operation is ion-coupled plasma reactive ion etching, and the exposure and development operation is performed by a stepping machine. The second dry etching operation is a dry acid etching operation. The method for fabricating a microstructure having a tapered structure according to claim 1, wherein the second wet etching operation is a high temperature wet acid etching operation, a dry acid etching operation or a high temperature wet acid etching operation. The acid etching solution has a temperature between 200 and 400 degrees Celsius, and the ratio of sulfuric acid to phosphoric acid in the acid etching solution is between 0.1 and 10. The method for fabricating a microstructure having a tapered structure according to claim 1, wherein the first portion of the body is controlled by adjusting a temperature of the second etching operation and a length of time One volume ratio of the second part.