MANUFACTURING METHOD OF HIGH REFLECTION MIRROR WITH POLYCRYSTALLINE ALUMINUM NITRIDE

Abstract

A manufacturing method of a high reflection mirror with polycrystalline aluminum nitride includes (A) providing a polycrystalline aluminum nitride substrate having a polished surface, and utilizing a magnetron sputtering apparatus to react an aluminum target and a plasma formed of nitrogen and argon for forming an aluminum nitride film on the surface of the polycrystalline aluminum nitride substrate, wherein the aluminum nitride film fills into a hole or a gap generated by a lattice defect of the surface of the polycrystalline aluminum nitride substrate; (B) thinning, grinding and polishing the aluminum nitride film for planarizing the polycrystalline aluminum nitride substrate; (C) forming an aluminum coating layer on the aluminum nitride film by a vacuum coating apparatus; (D) forming a sliver coating layer on the aluminum coating layer by another vacuum coating apparatus; and (E) forming a surface-protecting layer on the sliver coating layer.

Claims

1. A manufacturing method of a high reflection mirror with polycrystalline aluminum nitride, the manufacturing method comprising following steps: (A) providing a polycrystalline aluminum nitride substrate having a polished surface, and utilizing a magnetron sputtering apparatus to react an aluminum target and a plasma formed of nitrogen and argon for forming an aluminum nitride film on the surface of the polycrystalline aluminum nitride substrate, wherein the aluminum nitride film fills into a hole or a gap generated by a lattice defect of the surface of the polycrystalline aluminum nitride substrate; (B) thinning, grinding and polishing the aluminum nitride film for planarizing the polycrystalline aluminum nitride substrate; (C) forming an aluminum coating layer on the aluminum nitride film by a vacuum coating apparatus; (D) forming a sliver coating layer on the aluminum coating layer by another vacuum coating apparatus; and (E) forming a surface-protecting layer on the sliver coating layer.

2. The manufacturing method of the high reflection mirror with polycrystalline aluminum nitride of claim 1, wherein the polycrystalline aluminum nitride substrate of the step (A) is formed by a tape casting process or a high temperature sintering cutting molding process.

3. The manufacturing method of the high reflection mirror with polycrystalline aluminum nitride of claim 1, wherein a thermal conductance value of the polycrystalline aluminum nitride substrate having the polished surface of the step (A) is greater than or equal to 170 W.Math.m.sup.1.Math.K.sup.1, and a roughness average (Ra) of the polycrystalline aluminum nitride substrate ranges from 20 nm to 30 nm.

4. The manufacturing method of the high reflection mirror with polycrystalline aluminum nitride of claim 1, wherein before performing the step (A), the manufacturing method further comprises: (1) wiping the polycrystalline semiconductor substrate having the polished surface with a solvent comprising one of acetone, alcohol, and isopropyl alcohol to remove dirt; (2) removing organic residues and water vapor on the polished surface of the polycrystalline aluminum nitride substrate through an oxygen ion plasma.

5. The manufacturing method of the high reflection mirror with polycrystalline aluminum nitride of claim 4, wherein the oxygen ion plasma of step (2) is generated by a reactive ion etching (RIE) process or an induction coupling plasma etching (ICP) process.

6. The manufacturing method of the high reflection mirror with polycrystalline aluminum nitride of claim 4, wherein a gas source of the oxygen ion plasma of step (2) is a mixture gas of oxygen and argon.

7. The manufacturing method of the high reflection mirror with polycrystalline aluminum nitride of claim 1, wherein the magnetron sputtering apparatus of the step (A) is a direct current (DC) sputtering apparatus or a radio frequency (RF) magnetron sputtering apparatus.

8. The manufacturing method of the high reflection mirror with polycrystalline aluminum nitride of claim 1, wherein a thickness of the aluminum nitride film of step (A) ranges from 5 m to 15 m.

9. The manufacturing method of the high reflection mirror with polycrystalline aluminum nitride of claim 1, wherein a method of thinning, grinding and polishing of step (B) is a chemical mechanical polishing (CMP) method or a physical mechanical polishing (PMP) method.

10. The manufacturing method of the high reflection mirror with polycrystalline aluminum nitride of claim 1, wherein after thinning, grinding and polishing the aluminum nitride film of step (B), a thickness of the aluminum nitride film ranges from 5 m to 10 m.

11. The manufacturing method of the high reflection mirror with polycrystalline aluminum nitride of claim 1, wherein the vacuum coating apparatus of step (C) or step (D) is a vacuum evaporation coating apparatus or a magnetron sputtering coating apparatus.

12. The manufacturing method of the high reflection mirror with polycrystalline aluminum nitride of claim 1, wherein a thickness of the aluminum coating layer of step (C) is greater than 100 nm.

13. The manufacturing method of the high reflection mirror with polycrystalline aluminum nitride of claim 1, wherein a thickness of the sliver coating layer of step (D) is greater than 300 nm.

14. The manufacturing method of the high reflection mirror with polycrystalline aluminum nitride of claim 1, wherein the surface-protecting layer of step (E) comprises one of silicon oxide, magnesium fluoride or aluminum oxide.

15. The manufacturing method of the high reflection mirror with polycrystalline aluminum nitride of claim 1, wherein a thickness of the surface-protecting layer of step (E) ranges from 1 m to 3 m.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0023] The patent or application file contains at least one drawing executed in color. Copies of this patent or patent application publication with color drawing (s) will be provided by the Office upon request and payment of the necessary fee.

[0024] FIG. 1 is a flow diagram illustrating a manufacturing method of a high reflection mirror with polycrystalline aluminum nitride according to the present invention;

[0025] FIG. 2 is a schematic diagram illustrating a structure formed by a manufacturing method of a high reflection mirror with polycrystalline aluminum nitride according to the present invention;

[0026] FIG. 3 is a high magnification optical microscope analysis diagram illustrating a polished surface of a polycrystalline aluminum nitride substrate according to an embodiment of the present invention;

[0027] FIG. 4 is an electronic microscope analysis diagram illustrating a cross-section after sputtering an aluminum nitride film on a polycrystalline aluminum nitride substrate according to an embodiment of the present invention;

[0028] FIG. 5 is a high magnification optical microscope analysis diagram illustrating a surface after sputtering an aluminum nitride film and secondary polishing according to an embodiment of the present invention;

[0029] FIG. 6 is a scanning electronic microscope analysis diagram illustrating a cross-section and a top-view after forming an aluminum coating layer and a sliver coating layer on the polycrystalline aluminum nitride substrate according to an embodiment of the present invention; and

[0030] FIG. 7 is measuring diagram illustrating a reflectivity spectrum of a high reflection mirror with polycrystalline aluminum nitride according to an embodiment of the present invention.

DETAILED DESCRIPTION

[0031] Specific embodiments will be detailed in the follow description to explain an implementation of the present invention. Those skilled in the art can easily understand an advantage and an effect of the present invention from contents disclosed in this specification.

[0032] The present invention provides a manufacturing method of a high reflection mirror with polycrystalline aluminum nitride. First, the manufacturing method utilizes a process of filling the holes (or gaps) of a surface of a polycrystalline aluminum nitride substrate. A reactive magnetron sputtering technique is used to make ions of a target material with high energy be in contact with the surface of the polycrystalline aluminum nitride substrate, so as to form a compact aluminum nitride for filling the hole defects of the surface of the polycrystalline aluminum nitride substrate. Then, a secondary grinding and polishing process is utilized to remove the surface aluminum nitride film but remain the aluminum nitride filled into the defect, so as to enhance a smoothness of the surface and decrease light scattering loss caused by the holes or the gaps of the surface of the polycrystalline aluminum nitride substrate. Next, an aluminum coating layer and a sliver coating layer with specific thicknesses are manufactured on the polycrystalline aluminum nitride substrate after filling the holes (or the gaps), so as to enhance the reflectivity of near-ultraviolet reflectivity, the reflectivity of infrared light and the reflectivity of visible light of the high reflection mirror with polycrystalline aluminum nitride.

[0033] Referring to FIG. 1, FIG. 1 is a flow diagram illustrating a manufacturing method of a high reflection mirror with polycrystalline aluminum nitride according to the present invention. As shown in FIG. 1, the manufacturing method of the high reflection mirror with polycrystalline aluminum nitride includes: (A) providing a polycrystalline aluminum nitride substrate having a polished surface, and utilizing a magnetron sputtering apparatus to react an aluminum target and a plasma formed of nitrogen and argon for forming an aluminum nitride film on the surface of the polycrystalline aluminum nitride substrate, wherein the aluminum nitride film fills into the holes or gaps generated by a lattice defect of the surface of the polycrystalline aluminum nitride substrate (step S101); (B) thinning, grinding and polishing the aluminum nitride film for planarizing the polycrystalline aluminum nitride substrate (step S102); (C) forming an aluminum coating layer on the aluminum nitride film by a vacuum coating apparatus (step S103); (D) forming a sliver coating layer on the aluminum coating layer by a vacuum coating apparatus (step S104); and (E) forming a surface-protecting layer on the sliver coating layer (step S105). Referring to FIG. 2, FIG. 2 is a schematic diagram illustrating a structure formed by a manufacturing method of a high reflection mirror with polycrystalline aluminum nitride according to the present invention. As shown in FIG. 2, a high reflection coating film with aluminum nitride manufactured according to the present invention includes: the polycrystalline aluminum nitride substrate 100, a filled-hole 200 with aluminum nitride film, the high reflection aluminum coating layer 300, the high reflection sliver coating layer 400 and the surface-protecting layer 500.

[0034] Wherein, before performing the step (A), the manufacturing method may further include: (1) wiping the polycrystalline semiconductor substrate having the polished surface with a solvent comprising one of acetone, alcohol, and isopropyl alcohol to remove dirt; and (2) removing organic residues and water vapor on the polished surface of the polycrystalline aluminum nitride substrate through an oxygen ion plasma.

Embodiment 1

[0035] The polycrystalline aluminum nitride substrate having one single polished surface is provided, the thermal conductance value of the polycrystalline aluminum nitride substrate is 179W.Math.m.sup.1.Math.K.sup.1, and the roughness average (Ra) of the polished surface is 27 nm. The polished surface is wiped for cleaning by isopropyl alcohol. Referring to FIG. 3, FIG. 3 is a high magnification optical microscope analysis diagram illustrating a polished surface of a polycrystalline aluminum nitride substrate according to an embodiment of the present invention. As shown in FIG. 3, a size of the hole defect of the polished surface ranges from 5 m to 10 m when observing. Then, the polished surface of the polycrystalline aluminum nitride substrate is cleaned by oxygen ion plasma for 1 minute. After removing the organic residues and the water vapor, the polycrystalline aluminum nitride substrate is place into the high vacuum magnetron sputtering apparatus. When the manufactured processing condition of a vacuum level less than 510.sup.8 torr is achieved, by using 1.5KW manufactured processing power, the aluminum target and the plasma formed by the nitrogen of 12 sccm and the argon of 48 sccm are reacted to form aluminum nitride, such that the aluminum nitride is sputtered on the polished surface of the polycrystalline aluminum nitride substrate to form the aluminum nitride film. The process time is 40 minutes. Referring to FIG. 4, FIG. 4 is an electronic microscope analysis diagram illustrating a cross-section after sputtering an aluminum nitride film on a polycrystalline aluminum nitride substrate according to an embodiment of the present invention. As shown in FIG. 4, a thickness of the aluminum nitride film is 9.2 m by measured. Then, the surface thinning, grinding and polishing processes are performed to the polycrystalline aluminum nitride substrate with the aluminum nitride film filling the lattice defect of the polished surface. In the manufactured processing conditions, first, CMP80 (nanometer scale polishing liquid with main grain size of about 80 nm) is used to perform the polishing process at rotational speed of 30 rpm, temperature of 20 C. and processing pressure of 2 kg/cm.sup.2 for 20 minutes, and next, CMP20 (nanometer scale polishing liquid with main grain size of about 20 nm) is used to perform the polishing process at rotational speed of 30 rpm, temperature of 20 C. and processing pressure of 2 kg/cm.sup.2 for 10 minutes, so as to remove the aluminum nitride film on the surface of the substrate and remain the aluminum nitride sputter in the holes. Referring FIG. 5, FIG. 5 is a high magnification optical microscope analysis diagram illustrating a surface after sputtering an aluminum nitride film and secondary polishing according to an embodiment of the present invention. As shown in FIG. 5, by observation, the aluminum nitride film has filled the hole defects of the surface of the polycrystalline aluminum nitride substrate, and a diameter of the hole defect filled by the aluminum nitride film ranges from 5 m to 10 m. Thereafter, an aluminum coating layer with a thickness of 100 nm is formed on the polycrystalline aluminum nitride substrate by using a vacuum coating apparatus with a deposition rate of 1 nm/s, so as to enhance the reflectivity of near-ultraviolet. A sliver coating layer with a thickness of 300 nm is formed on the aluminum coating layer by using the vacuum coating apparatus, so as to enhance the reflectivity of infrared light and the reflectivity of visible light. Referring to FIG. 6, FIG. 6 is a scanning electronic microscope analysis diagram illustrating a cross-section and a top-view after forming an aluminum coating layer and a sliver coating layer on the polycrystalline aluminum nitride substrate according to an embodiment of the present invention. As shown in FIG. 6, the reflection coating layers have been coated on this high reflection mirror with polycrystalline aluminum nitride. Then, a magnesium fluoride protecting layer with a thickness of 1 m is formed on the reflection coating layer by the vacuum coating apparatus. After that, the reflectivity spectrum of the high reflection mirror with polycrystalline aluminum nitride is measured. Referring to FIG. 7, FIG. 7 is measuring diagram illustrating a reflectivity spectrum of a high reflection mirror with polycrystalline aluminum nitride according to an embodiment of the present invention. As shown in the reflectivity spectrum of the high reflection mirror with polycrystalline aluminum nitride, the reflectivity corresponding to the range from near-ultraviolet region to infrared light region (365 nm-1000 nm) is higher than or equal to 90%, wherein the reflectivity of near-ultraviolet with a wavelength of 365 nm is 91.1%.

Embodiment 2

[0036] The polycrystalline aluminum nitride substrate having one single polished surface is provided, the thermal conductance value of the polycrystalline aluminum nitride substrate is 176 m, and the roughness average (Ra) of the polished surface is 23 nm. The polished surface is wiped for cleaning by isopropyl alcohol. Then, the polished surface of the polycrystalline aluminum nitride substrate is cleaned by oxygen ion plasma for 1 minute. After removing the organic residues and the water vapor, the polycrystalline aluminum nitride substrate is placed into the high vacuum magnetron sputtering apparatus. When the manufactured processing condition of a vacuum level less than 510.sup.8 torr is achieved, by using 1.5KW manufactured processing power, the aluminum target and the plasma formed by the nitrogen of 20 sccm and the argon of 40 sccm are reacted to form aluminum nitride, such that the aluminum nitride is sputtered on the polished surface of the polycrystalline aluminum nitride substrate to form the aluminum nitride film. The process time is 40 minutes. The thickness of the aluminum nitride film is 11.5 m by measured. Thereafter, the surface thinning, grinding and polishing processes are performed to the polycrystalline aluminum nitride substrate with the aluminum nitride film filling the lattice defect of the polished surface. In the manufactured processing conditions, first, CMP80 (nanometer scale polishing liquid with main grain size of about 80 nm) is used to perform the polishing process at rotational speed of 30 rpm, temperature of 20 C. and processing pressure of 2 kg/cm.sup.2 for 20 minutes, and next, CMP20 (nanometer scale polishing liquid with main grain size of about 20 nm) is used to performed the polishing process at rotational speed of 30 rpm, temperature of 20 C. and processing pressure of 2 kg/cm.sup.2 for 10 minutes, so as to remove the aluminum nitride film on the surface of the substrate and remain the aluminum nitride sputter in the holes. Thus, the hole filling process and the secondary polishing process of the aluminum nitride film are completed. By observation, the aluminum nitride film has filled the hole defects of the surface of the polycrystalline aluminum nitride substrate, and the diameter of the hole defects filled by the aluminum nitride film ranges from 5 m to 10 m. Thereafter, an aluminum coating layer with a thickness of 100 nm is formed on the polycrystalline aluminum nitride substrate by using the vacuum coating apparatus with a deposition rate of 0.5 nm/s, so as to enhance the reflectivity of near-ultraviolet. A sliver coating layer with a thickness of 300 nm is formed on the aluminum coating layer by using the vacuum coating apparatus, so as to enhance the reflectivity of infrared light and the reflectivity of visible light. Then, a magnesium fluoride protecting layer with a thickness of 1 m is formed on the reflection coating layer by the vacuum coating apparatus. After that, the reflectivity spectrum of the high reflection mirror with polycrystalline aluminum nitride is measured. The measuring result of the reflectivity spectrum of the high reflection mirror with polycrystalline aluminum nitride shows that the reflectivity corresponding to the range from near-ultraviolet region to infrared light region (365 nm-1000 nm) is higher than or equal to 90%, wherein the reflectivity of near-ultraviolet with a wavelength of 365 nm is 92.4%.

[0037] Compared with the conventional high reflection mirror, in the present invention, the holes or the gaps generated by the lattice defect of the polycrystalline ceramic is effectively reduced by the hole filling process and the secondary polishing process of the polycrystalline aluminum nitride film, so as to enhance the smoothness of the substrate and the reflection efficiency. Therefore, the polycrystalline aluminum nitride substrate has better thermal conductivity compared with a glass substrate or a polymer substrate. The polycrystalline aluminum nitride substrate has less surface defect and better reflectivity compared with a polycrystalline ceramic substrate. The polycrystalline aluminum nitride substrate has a cost vantage cost compared with a monocrystalline ceramic substrate. The polycrystalline aluminum nitride substrate has better insulating property compared with a metal substrate. By forming the stack including the aluminum coating layer and the sliver coating layer with specific thicknesses, the high reflection requirements of near-ultraviolet light, visible light and infrared light are achieved simultaneously with less metal reflection layers. As a result, the high reflection mirror with polycrystalline aluminum nitride may achieve the competitive advantages including high thermal conductivity, high insulation, high reflectivity of wide frequency band and low cost, and the high reflection mirror with polycrystalline aluminum nitride can be applied to a high-power light-emitting component with the thermal dissipation requirement, so as to make it be used widely in the future.

[0038] The above embodiments are merely to explain the features and effects of the present invention and not to limit the scope of the present invention. Those skilled in the art will readily observe that numerous modifications and alterations of the device and method may be made without departing from the spirit and scope of the invention. Accordingly, the above disclosure should be construed as limited only by the metes and bounds of the appended claims.