CN112735936A - Micro-mirror side wall processing method for etching by inductively coupled plasma and focused ion beam - Google Patents
Micro-mirror side wall processing method for etching by inductively coupled plasma and focused ion beam Download PDFInfo
- Publication number
- CN112735936A CN112735936A CN202110005187.4A CN202110005187A CN112735936A CN 112735936 A CN112735936 A CN 112735936A CN 202110005187 A CN202110005187 A CN 202110005187A CN 112735936 A CN112735936 A CN 112735936A
- Authority
- CN
- China
- Prior art keywords
- ion beam
- focused ion
- etching
- reflector
- mirror surface
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Granted
Links
Images
Classifications
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01J—ELECTRIC DISCHARGE TUBES OR DISCHARGE LAMPS
- H01J37/00—Discharge tubes with provision for introducing objects or material to be exposed to the discharge, e.g. for the purpose of examination or processing thereof
- H01J37/32—Gas-filled discharge tubes
- H01J37/32009—Arrangements for generation of plasma specially adapted for examination or treatment of objects, e.g. plasma sources
- H01J37/32082—Radio frequency generated discharge
- H01J37/321—Radio frequency generated discharge the radio frequency energy being inductively coupled to the plasma
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B81—MICROSTRUCTURAL TECHNOLOGY
- B81B—MICROSTRUCTURAL DEVICES OR SYSTEMS, e.g. MICROMECHANICAL DEVICES
- B81B7/00—Microstructural systems; Auxiliary parts of microstructural devices or systems
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B81—MICROSTRUCTURAL TECHNOLOGY
- B81C—PROCESSES OR APPARATUS SPECIALLY ADAPTED FOR THE MANUFACTURE OR TREATMENT OF MICROSTRUCTURAL DEVICES OR SYSTEMS
- B81C1/00—Manufacture or treatment of devices or systems in or on a substrate
- B81C1/00015—Manufacture or treatment of devices or systems in or on a substrate for manufacturing microsystems
- B81C1/00206—Processes for functionalising a surface, e.g. provide the surface with specific mechanical, chemical or biological properties
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B81—MICROSTRUCTURAL TECHNOLOGY
- B81C—PROCESSES OR APPARATUS SPECIALLY ADAPTED FOR THE MANUFACTURE OR TREATMENT OF MICROSTRUCTURAL DEVICES OR SYSTEMS
- B81C1/00—Manufacture or treatment of devices or systems in or on a substrate
- B81C1/00436—Shaping materials, i.e. techniques for structuring the substrate or the layers on the substrate
- B81C1/00523—Etching material
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01J—ELECTRIC DISCHARGE TUBES OR DISCHARGE LAMPS
- H01J2237/00—Discharge tubes exposing object to beam, e.g. for analysis treatment, etching, imaging
- H01J2237/32—Processing objects by plasma generation
- H01J2237/33—Processing objects by plasma generation characterised by the type of processing
- H01J2237/334—Etching
Landscapes
- Engineering & Computer Science (AREA)
- Manufacturing & Machinery (AREA)
- Microelectronics & Electronic Packaging (AREA)
- Physics & Mathematics (AREA)
- Plasma & Fusion (AREA)
- Chemical & Material Sciences (AREA)
- Analytical Chemistry (AREA)
- Health & Medical Sciences (AREA)
- Life Sciences & Earth Sciences (AREA)
- General Health & Medical Sciences (AREA)
- Molecular Biology (AREA)
- Computer Hardware Design (AREA)
- Micromachines (AREA)
- Drying Of Semiconductors (AREA)
- ing And Chemical Polishing (AREA)
Abstract
The invention relates to a micromirror side wall processing method for etching inductively coupled plasma and focused ion beams. The method comprises the following steps: firstly, processing an optical switch by utilizing an Inductively Coupled Plasma (ICP) technology to obtain an optical switch sample; then, utilizing Focused Ion Beam (FIB) technique to make secondary etching processing on the sample side wall reflector mirror surface, and concretely making it include the following steps: a sample fixing step, fixing a sample to be processed on a sample table in a dual-beam system of a focused ion beam and an electron beam; selecting appropriate areas to be processed and experimental areas for touching the bottom, and then performing simulated processing on the experimental areas for touching the bottom to determine appropriate processing parameters; and a processing step, etching the mirror surface of the reflector by using the focused ion beam. The processing method based on the combination of the inductive coupling plasma technology and the focused ion beam technology can effectively improve the roughness of the mirror surface and improve the transmission efficiency of the optical path.
Description
Technical Field
The invention relates to the technical field of mirror surface roughness processing and etching, in particular to a micromirror side wall processing method for etching by inductively coupled plasma and focused ion beams.
Background
The traditional technological process for processing the optical switch based on the Inductively Coupled Plasma (ICP) technology comprises complex interaction of chemical and physical processes, the roughness of the mirror surface of the reflector of the finally obtained micro-optical switch sample is larger, and the optical path transmission efficiency of the optical switch is reduced.
The focused ion beam etching technology is one of the most accurate nanometer processing methods under the current technical conditions, and the focused ion beam has no material selectivity and can process any hard metal and non-metal materials. The invention relates to a micromirror side wall processing method for etching inductively coupled plasma and focused ion beams, which comprises the following steps: firstly, processing a low-light-level switch by using inductively coupled plasma to obtain an optical switch sample with larger mirror roughness; then utilizing the focused ion beam to etch the side wall reflector mirror surface, i.e. utilizing high-energy ion beam to bombard the reflector mirror surface, directly striking the high-energy ion beam on the reflector mirror surface to etch, eliminating the pit of the mirror surface, improving the roughness and achieving the purpose of improving the transmission efficiency of the optical switch optical path.
Patent document 1 CN107611207A
Disclosure of Invention
In order to overcome the defects of the prior art, the technical problem to be solved by the invention is to provide a micromirror side wall processing method by utilizing inductively coupled plasma and focused ion beam etching, wherein the mirror surface of a side wall reflector of a micro-optical switch is etched by utilizing the inductively coupled plasma and the focused ion beam, so that the roughness of the side wall reflector is improved, and the optical path transmission efficiency of the optical switch is improved.
In order to achieve the purpose, the invention adopts the technical scheme that: a method for processing the side wall of a micro-mirror etched by inductively coupled plasma and focused ion beams utilizes the inductively coupled plasma and the focused ion beams to respectively process and etch the mirror surface of a side wall reflector of a micro-light switch, and the method for processing the side wall reflector of the micro-light switch comprises the following steps:
(1) processing the optical switch by utilizing an Inductively Coupled Plasma (ICP) technology to obtain an optical switch sample with a larger surface roughness of a reflector;
the method is characterized in that the optical switch reflector mirror surface is etched by utilizing a Focused Ion Beam (FIB) technology, the roughness of the mirror surface is improved, and the method specifically comprises the following steps:
(2) fixing an optical switch sample on a sample table of a double-beam system;
(3) selecting processing parameters: selecting a reflector mirror surface to be processed under an electron beam window, finding an adjacent area beside the mirror surface to be processed as a background touch experiment area, performing simulation processing on the background touch experiment area by utilizing a focused ion beam, selecting current with proper magnitude as etching current of the area to be processed under the conditions of comprehensive processing time and roughness after processing, and determining processing parameters such as height, width and depth of a side wall to be processed, ion beam current and the like;
(4) the processing steps are as follows: setting various determined parameters, and etching the side wall reflector mirror surface to be processed by utilizing the focused ion beam.
The invention discloses a method for improving side wall roughness by utilizing an inductive coupling plasma technology and a focused ion beam technology, which comprises the following steps: the invention relates to a side wall reflector mirror surface roughness processing method based on the combination of an Inductively Coupled Plasma (ICP) technology and a Focused Ion Beam (FIB) technology.
The invention discloses a method for improving side wall roughness by utilizing an inductive coupling plasma technology and a focused ion beam technology, which comprises the following steps: in the step (1), the micro-light switch processed by the Inductively Coupled Plasma (ICP) technology causes more pits on the reflector surface, so that the roughness of the reflector surface is larger, and the pits can be effectively eliminated by etching the reflector surface by using the focused ion beam, so that the roughness of the reflector surface is improved, and the light path transmission efficiency of the light switch is improved.
The invention discloses a method for improving side wall roughness by utilizing an inductive coupling plasma technology and a focused ion beam technology, which comprises the following steps: in the step (2), when the mirror surface of the reflector is etched by using the focused ion beam technology, the processed optical switch sample needs to be placed on a sample table with the focused ion beam and an electron beam, wherein the electron beam is used for searching and determining parameters such as the width, the height, the depth and the like of the mirror surface area to be processed, and the focused ion beam is used for etching the mirror surface.
The invention discloses a method for improving side wall roughness by utilizing an inductive coupling plasma technology and a focused ion beam technology, which comprises the following steps: in the step (4), when the mirror surface of the reflector is etched by using the focused ion beam, the region to be processed is found under an electron beam window with the voltage of 30kV and the magnification of 1600x, and then the whole region to be processed is etched under the focused ion beam window with the current of 9.3 nA.
The invention discloses a method for improving side wall roughness by utilizing an inductive coupling plasma technology and a focused ion beam technology, which comprises the following steps: in the step (4), when the focused ion beam technology is used for etching the optical switch reflector, in a dual-beam system, the ion beam and the electron beam form an included angle of 52 degrees.
The invention discloses a method for improving side wall roughness by utilizing an inductive coupling plasma technology and a focused ion beam technology, which comprises the following steps: and characterizing the roughness of the mirror surface of the reflector by using an atomic force microscope, and analyzing the roughness of the mirror surface of the optical switch reflector before and after etching to obtain comparison data for improving the roughness before and after etching.
The scheme of etching the side wall reflector mirror surface by adopting the processing method combining the inductively coupled plasma technology and the focused ion beam technology can effectively improve the roughness of the mirror surface and improve the light path transmission efficiency of the optical switch.
Drawings
FIG. 1 is a schematic diagram of an inductively coupled plasma process for a micro-optical switch
FIG. 2 is a schematic view of the mirror surface of the etched front mirror under an atomic force microscope
FIG. 3 is a schematic view of the mirror surface of the etched reflector under an atomic force microscope
FIG. 4 is a schematic side view of a focused ion beam machined mirror surface
Detailed Description
In order to make the objects, technical solutions and advantages of the present invention more clearly and completely apparent, the technical solutions in the embodiments of the present invention will be described below with reference to the accompanying drawings. It should be noted that the embodiments described herein are only for explaining the present invention and are not used to limit the present invention. The embodiments described are only a part of the embodiments of the present invention, and not all of them. All other embodiments, which can be obtained by a person skilled in the art without any inventive step based on the embodiments of the present invention, are within the scope of the present invention. In the following description, numerous specific details of the invention, such as structure, materials, dimensions, processing instructions and techniques of the device are described in order to provide a more thorough understanding of the invention. However, as will be understood by those skilled in the art, the present invention may be practiced without these specific details.
Fig. 1 is a schematic flow chart of processing an optical switch by using the ICP technique: the processing flow comprises photoresist homogenizing photoetching, electrode manufacturing, front ICP etching, back ICP etching, silicon oxide removal and the like. The micro-optical switches are processed on the SOI wafer, and the thicknesses of the device layer, the buried oxide layer and the processing layer are 125 microns, 0.5 microns and 350 microns respectively. The optical switch is fabricated using a double-sided etching process with Inductively Coupled Plasma (ICP) technology. The metal layer pattern is transferred to the front surface of the wafer by standard spin coating, photolithography and development processes. A Cr/Au (20/500 nm thick) film with high resistivity to HF etch was produced by the sputtering and lift-off steps. The AZ4620 resist was then transferred to the surface by spin coating, photolithography and development processes. The device layers were etched by an Inductively Coupled Plasma (ICP) process using the patterned AZ4620 as a mask layer. Wafer post-processing is a critical step to achieve large air gaps. The wafer was rinsed in acetone before the reverse treatment was performed. The diluted AZ4620 resist was transferred to the wafer using spray, photolithography and development processes. The sprayed AZ4620 is also used as a mask layer for the wafer backside ICP process. After the excess SiO2 layer was removed with HF solution, the device was released.
FIG. 4 is a schematic diagram of a side-wall mirror surface processed by FIB technology, in which high-energy ion beams directly bombard the side-wall mirror surface to etch the mirror surface, so as to eliminate pits on the mirror surface and improve the roughness of the mirror surface.
As can be seen from a comparison of fig. 2 and 3, the roughness of the mirror surface changes very significantly. FIG. 3 is a scanned view of the mirror surface before etching by focused ion beam, in which the surface has more pits and greater depth, resulting in a larger roughness of the mirror surface, and the average roughness of the mirror surface reaches 123 nm. FIG. 4 is a scanned view of the mirror surface etched by the focused ion beam, wherein the depth of the mirror surface etched by the focused ion beam is set to be 1.5 μm, pits on the etched mirror surface are obviously reduced, the depth of the pits is also obviously reduced, and the average roughness is only 29nm finally.
A sample fixing step, namely fixing a sidewall reflector sample processed by an inductive coupling plasma technology on a sample table, wherein the specific method comprises the following steps: the sidewall sample is placed on a sample table, the bottom of the sidewall sample is adhered to the sample table through conductive adhesive, and the sidewall sample and the sample table are fixed into a whole, and it is noted that the sample table is fixed in a dual-beam system with a focused ion beam and an electron beam, and the electron beam and the focused ion beam form an included angle of 52 degrees.
The method comprises the following steps of selecting processing parameters, finding a to-be-processed area and a background experiment area of a side wall sample, and specifically comprises the following steps: in an electron beam window of a dual-beam system, a side wall reflector to be processed is found under the voltage of 30kV and the magnification of 1600x, and an adjacent mirror surface is found beside an area to be processed to serve as a background experiment area. Firstly, processing a background experiment area by utilizing a focused ion beam: under an ion beam window, respectively etching a rectangular processing area with the side wall height of 5 micrometers, the width of 5 micrometers and the depth of 1.0 micrometer in a bottom touch experiment area by using currents of 80pA, 0.23nA, 9.3nA and 65nA, comprehensively comparing the processing time of various currents and the roughness improvement condition of the bottom touch experiment area after processing is finished, and finally selecting the ion beam current with the size of 9.3nA as the current for processing the side wall reflecting mirror surface; then, rectangular areas with the depths of 0.5 mu m, 1.0 mu m, 1.5 mu m, 2.0 mu m and 2.5 mu m are respectively etched under the current of 9.3nA, the height and the width of the rectangular side wall are still selected to be 5 mu m, after the processing is finished, the length of the processing time of each depth rectangular area and the improvement condition of the roughness after the processing are integrated, and finally, the side wall with the height and the width of 5 mu m and the depth of 2.0 mu m is selected as an experimental area to be processed.
And a processing step, namely after reasonably selecting the current of the focused ion beam and the depth of the side wall region to be processed, etching the side wall reflector mirror surface by utilizing the focused ion beam: firstly, finding a side wall area to be processed in an electron beam window under the voltage of 30kV and the magnification of 1600 x; and then, etching the to-be-processed side wall region with the depth of 2.0 mu m by using a focused ion beam with the current of 9.3nA under an ion beam window, and finishing the whole processing process after the etching process is finished.
Claims (7)
1. A method for processing the side wall of a micromirror etched by inductively coupled plasma and focused ion beams, which respectively processes and etches the mirror surface of a side wall reflector of an optical switch by utilizing the inductively coupled plasma technology and the focused ion beam technology, comprises the following steps:
(1) processing the optical switch by utilizing an Inductively Coupled Plasma (ICP) technology to obtain an optical switch sample with a larger surface roughness of a reflector;
the method is characterized in that the optical switch reflector mirror surface is etched by utilizing a Focused Ion Beam (FIB) technology, the roughness of the mirror surface is improved, and the method specifically comprises the following steps:
(2) fixing an optical switch sample on a sample stage of a dual-beam system with a focused ion beam and an electron beam;
(3) selecting processing parameters: selecting a side wall reflector mirror surface to be processed under an electron beam window, finding an adjacent area beside the mirror surface to be processed as a background experiment area, utilizing a focused ion beam to carry out simulation processing on the background experiment area, selecting current with proper magnitude as etching current of the area to be processed under the conditions of comprehensive processing time and roughness after processing, and determining processing parameters such as height, width and depth of the area to be processed, ion beam current and the like;
(4) the processing steps are as follows: setting various determined parameters, and etching the mirror surface of the reflector by using the focused ion beam.
2. The method of claim 1, wherein the step of etching the side wall of the micromirror by inductively coupled plasma and focused ion beam comprises: the invention relates to a side wall reflector mirror surface roughness processing method based on the combination of an Inductively Coupled Plasma (ICP) technology and a Focused Ion Beam (FIB) technology.
3. The method of claim 1, wherein the step of etching the side wall of the micromirror by inductively coupled plasma and focused ion beam comprises: in the step (1), the micro-light switch processed by the Inductively Coupled Plasma (ICP) technology can cause more pits on the surface of the reflector, and the roughness of the reflector is larger, and the pits can be effectively eliminated by etching the reflector by using the focused ion beam, so that the roughness of the reflector is improved, and the optical path transmission efficiency of the optical switch is improved.
4. The method of claim 1, wherein the step of etching the side wall of the micromirror by inductively coupled plasma and focused ion beam comprises: in the step (2), when the mirror surface of the reflector is etched by using the focused ion beam technology, the processed optical switch sample needs to be placed on a sample table with the focused ion beam and an electron beam, wherein the electron beam is used for searching and determining parameters such as the width, the height, the depth and the like of the mirror surface area to be processed, and the focused ion beam is used for etching the mirror surface.
5. The method of claim 1, wherein the step of etching the side wall of the micromirror by inductively coupled plasma and focused ion beam comprises: in the step (4), when the mirror surface of the reflector is etched by using the focused ion beam, the region to be processed is found under an electron beam window with the voltage of 30kV and the magnification of 1600x, and then the whole region to be processed is etched under the focused ion beam window with the current of 9.3 nA.
6. The method of claim 1, wherein the step of etching the side wall of the micromirror by inductively coupled plasma and focused ion beam comprises: in the step (4), when the focused ion beam technology is used for etching the optical switch reflector, in a dual-beam system, the ion beam and the electron beam form an included angle of 52 degrees.
7. The method of claim 1, wherein the step of etching the side wall of the micromirror by inductively coupled plasma and focused ion beam comprises: and characterizing the roughness of the mirror surface of the reflector by using an atomic force microscope, and analyzing the roughness of the mirror surface of the optical switch reflector before and after etching to obtain comparison data for improving the roughness before and after etching.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202110005187.4A CN112735936B (en) | 2021-01-04 | 2021-01-04 | Micro-light switch processing method for etching by inductively coupled plasma and focused ion beam |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202110005187.4A CN112735936B (en) | 2021-01-04 | 2021-01-04 | Micro-light switch processing method for etching by inductively coupled plasma and focused ion beam |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN112735936A true CN112735936A (en) | 2021-04-30 |
| CN112735936B CN112735936B (en) | 2022-06-10 |
Family
ID=75590765
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN202110005187.4A Active CN112735936B (en) | 2021-01-04 | 2021-01-04 | Micro-light switch processing method for etching by inductively coupled plasma and focused ion beam |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN112735936B (en) |
Citations (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN101008694A (en) * | 2006-01-26 | 2007-08-01 | 中国科学院微电子研究所 | Design and manufacture technology of optical switch |
| CN102064077A (en) * | 2010-12-02 | 2011-05-18 | 北京航空航天大学 | Method for improving focused ion beam machining accuracy by synchronous controllable electron beam |
| CN104297948A (en) * | 2014-09-14 | 2015-01-21 | 吉林大学 | Waveguide thermal optical switch based on long-period metal surface plasma and preparation method of waveguide thermal optical switch |
| KR20150134080A (en) * | 2014-05-21 | 2015-12-01 | (주)이노벡테크놀러지 | Fouced Ion Beam Apparatus |
-
2021
- 2021-01-04 CN CN202110005187.4A patent/CN112735936B/en active Active
Patent Citations (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN101008694A (en) * | 2006-01-26 | 2007-08-01 | 中国科学院微电子研究所 | Design and manufacture technology of optical switch |
| CN102064077A (en) * | 2010-12-02 | 2011-05-18 | 北京航空航天大学 | Method for improving focused ion beam machining accuracy by synchronous controllable electron beam |
| KR20150134080A (en) * | 2014-05-21 | 2015-12-01 | (주)이노벡테크놀러지 | Fouced Ion Beam Apparatus |
| CN104297948A (en) * | 2014-09-14 | 2015-01-21 | 吉林大学 | Waveguide thermal optical switch based on long-period metal surface plasma and preparation method of waveguide thermal optical switch |
Non-Patent Citations (2)
| Title |
|---|
| IN-HYOUK SONG等: "Smoothing dry-etched microstructure sidewalls using focused ion beam milling for optical applications", 《JOURNAL OF MICROMECHANICS AND MICROENGINEERING》 * |
| IN-HYOUK SONG等: "Smoothing dry-etched microstructure sidewalls using focused ion beam milling for optical applications", 《JOURNAL OF MICROMECHANICS AND MICROENGINEERING》, vol. 17, no. 8, 13 July 2007 (2007-07-13), pages 1593 - 1597, XP020120195, DOI: 10.1088/0960-1317/17/8/023 * |
Also Published As
| Publication number | Publication date |
|---|---|
| CN112735936B (en) | 2022-06-10 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| JP5264237B2 (en) | Nanostructure and method for producing nanostructure | |
| EP1518150B1 (en) | Method of reticle fabrication using an amorphous carbon layer | |
| US7378654B2 (en) | Processing probe | |
| CN112735936B (en) | Micro-light switch processing method for etching by inductively coupled plasma and focused ion beam | |
| US9291913B2 (en) | Pattern generator for a lithography system | |
| KR100770196B1 (en) | Substrate for transfer mask, transfer mask, and method of manufacture thereof | |
| US20080073522A1 (en) | Method of correcting opaque defect of chrome mask, in which atomic force microscope fine working apparatus has been used | |
| JP2009295790A (en) | Pattern forming method | |
| JP4422528B2 (en) | Method for manufacturing transfer mask for charged particle beam | |
| JP2007035679A (en) | Etching mask and dry etching method | |
| JP2012033608A (en) | Method for manufacturing reflective mask for euv exposure | |
| JP2001142194A (en) | Method for manufacturing phase shift mask | |
| KR100826587B1 (en) | Thin film patterning method using atomic force microscope lithography system | |
| CN112394614A (en) | Mask, mask defect repairing method, mask using method and semiconductor structure | |
| KR100869546B1 (en) | Fabrication method of thin film pattern using atomic force microscope lithography | |
| CN104345548A (en) | Manufacturing method of submicron mask plate | |
| KR20200070625A (en) | Method for manufacturing nanostructure and nanostructure manufactured by using the same | |
| JP2002303966A (en) | Method for producing mask | |
| Kim | Ion beam trimming of aluminium nitride thin film with silicon dioxide mask | |
| JP5423073B2 (en) | Stencil mask and electron beam exposure method | |
| JPH02192714A (en) | Formation of resist pattern | |
| KR940009996B1 (en) | Manufacturing method of semiconductor device | |
| Bogue | Developments in advanced silicon etching techniques by STS Systems | |
| Tian | Sub 10-nm Nanopantography and Nanopattern Transfer Using Highly Selective Plasma Etching | |
| KR100219398B1 (en) | Photomask manufacturing method |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| PB01 | Publication | ||
| PB01 | Publication | ||
| SE01 | Entry into force of request for substantive examination | ||
| SE01 | Entry into force of request for substantive examination | ||
| GR01 | Patent grant | ||
| GR01 | Patent grant |