CN110335807B - Silicon wafer cleaning method - Google Patents
Silicon wafer cleaning method Download PDFInfo
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- CN110335807B CN110335807B CN201910546947.5A CN201910546947A CN110335807B CN 110335807 B CN110335807 B CN 110335807B CN 201910546947 A CN201910546947 A CN 201910546947A CN 110335807 B CN110335807 B CN 110335807B
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- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
- H01L21/00—Processes or apparatus adapted for the manufacture or treatment of semiconductor or solid state devices or of parts thereof
- H01L21/02—Manufacture or treatment of semiconductor devices or of parts thereof
- H01L21/02041—Cleaning
- H01L21/02057—Cleaning during device manufacture
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- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
- H01L21/00—Processes or apparatus adapted for the manufacture or treatment of semiconductor or solid state devices or of parts thereof
- H01L21/67—Apparatus specially adapted for handling semiconductor or electric solid state devices during manufacture or treatment thereof; Apparatus specially adapted for handling wafers during manufacture or treatment of semiconductor or electric solid state devices or components ; Apparatus not specifically provided for elsewhere
- H01L21/67005—Apparatus not specifically provided for elsewhere
- H01L21/67011—Apparatus for manufacture or treatment
- H01L21/67017—Apparatus for fluid treatment
- H01L21/67028—Apparatus for fluid treatment for cleaning followed by drying, rinsing, stripping, blasting or the like
- H01L21/6704—Apparatus for fluid treatment for cleaning followed by drying, rinsing, stripping, blasting or the like for wet cleaning or washing
- H01L21/67051—Apparatus for fluid treatment for cleaning followed by drying, rinsing, stripping, blasting or the like for wet cleaning or washing using mainly spraying means, e.g. nozzles
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- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
- H01L21/00—Processes or apparatus adapted for the manufacture or treatment of semiconductor or solid state devices or of parts thereof
- H01L21/67—Apparatus specially adapted for handling semiconductor or electric solid state devices during manufacture or treatment thereof; Apparatus specially adapted for handling wafers during manufacture or treatment of semiconductor or electric solid state devices or components ; Apparatus not specifically provided for elsewhere
- H01L21/67005—Apparatus not specifically provided for elsewhere
- H01L21/67011—Apparatus for manufacture or treatment
- H01L21/67017—Apparatus for fluid treatment
- H01L21/67028—Apparatus for fluid treatment for cleaning followed by drying, rinsing, stripping, blasting or the like
- H01L21/6704—Apparatus for fluid treatment for cleaning followed by drying, rinsing, stripping, blasting or the like for wet cleaning or washing
- H01L21/67057—Apparatus for fluid treatment for cleaning followed by drying, rinsing, stripping, blasting or the like for wet cleaning or washing with the semiconductor substrates being dipped in baths or vessels
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- Engineering & Computer Science (AREA)
- Physics & Mathematics (AREA)
- Condensed Matter Physics & Semiconductors (AREA)
- General Physics & Mathematics (AREA)
- Manufacturing & Machinery (AREA)
- Computer Hardware Design (AREA)
- Microelectronics & Electronic Packaging (AREA)
- Power Engineering (AREA)
- Cleaning Or Drying Semiconductors (AREA)
Abstract
The invention provides a silicon wafer cleaning method which comprises five main steps of SC-1 cleaning, ozone water cleaning, DIW cleaning, HF treatment and lifting drying, wherein the step of pure water overflow cleaning after SC-1 cleaning in the prior art is replaced by ozone water cleaning, a silicon wafer is placed into a cleaning tank in a vertical state for soaking for 5-7 min, a rapid liquid discharge valve at the bottom of the tank is immediately opened for rapid liquid discharge, two spray pipes are opened at the same time for liquid discharge, nozzles on the spray pipes simultaneously and uniformly spray two sides of the silicon wafer, the water spray pressure of each nozzle is 0.2-0.3 MPa, the flow is 2-3 l/min, and the interval between the silicon wafer and the nozzles is 10-15 cm. The metal hydroxide complex ions on the silicon wafer are quickly oxidized into hydroxide in a short time by spraying, the hydroxide flows to the bottom of the ozone water cleaning tank under the action of spraying liquid flow and is quickly discharged through a quick liquid discharge valve, so that the retention time and the opportunity of reattachment are avoided, and the removal of the metal hydroxide complex ions is realized.
Description
Technical Field
The invention relates to the technical field of silicon wafer cleaning, in particular to a silicon wafer cleaning method.
Background
The semiconductor silicon chip is an indispensable semiconductor material in the fields of automobiles, mobile phones, PCs and the like. With the development of lightness and concentration of semiconductor devices, higher requirements are also placed on silicon wafers as base materials, and particularly, the silicon wafers are required to be higher in standard grade in the aspect of cleanness. Therefore, it is imperative to improve the cleaning process capability in the silicon wafer manufacturing process.
In the process of manufacturing a silicon wafer, it is necessary to perform a process such as polishing or grinding, and in the process, a polishing liquid containing aluminum and silicon dust is used, so that fine metal ions containing metal grinding dust and abrasive particles remain on the surface of the silicon wafer, and are difficult to remove during cleaning, which affects the quality of the silicon wafer.
As an improvement, in general, cleaning treatment using a chemical solution such as SC-1(APM), SC-2(HPM), a surfactant, ozone water, or the like is attempted at the time of cleaning. Although metal ions and metal oxides can be removed from the silicon wafer, the effect on metal hydroxide [ M (OH) x ] -complex ions is not obvious, the complex ions cannot be completely removed, and the complex ions still remain on the surface of the product silicon wafer.
In order to solve the problem of ion residue, a metal ion filter is mounted on a liquid medicine tank, but the metal hydroxide complex ions (especially aluminum ions and iron ions which are easy to form metal hydroxide) cannot be effectively removed, and an effective removal method is not found at present.
Disclosure of Invention
The present invention has been made to solve the above-mentioned problems, and is directed to a characteristic of a metal hydroxide complex ion having a strong adhesive force, and to effectively remove such a metal hydroxide complex ion difficult to remove by using an ozone water immersion and spray method.
In the conventional silicon wafer cleaning equipment, after a treatment with a chemical solution such as an alkaline SC-1, the residual chemical solution is cleaned in a subsequent tank, and then the cleaned residual chemical solution is poured into a tank in which pure water overflows. The treatment method has no effect on the metal hydroxide, and the metal hydroxide still maintains the original state and remains and is adsorbed on the surface of the silicon wafer.
The main purpose of the invention is to prevent the adsorption, after SC-1 treatment, ozone water is firstly used for spraying to accelerate the oxidation process of metal hydroxide complex ions, and the chemical reaction principle is as follows:
Al(OH)4 -+O3→2Al(OH)3+H2O+2O2
the charge property of the surface of the silicon wafer is biased to neutral through oxidation, so that the adsorption force on the silicon wafer is reduced on one hand, and the metal ions can be completely separated from the surface of the silicon wafer through the mechanical impact force of spraying on the other hand.
The invention improves an ozone water tank used in conventional overflow, two spray pipes with nozzles are arranged above the ozone water tank and are respectively arranged at two sides of a silicon wafer, and a rapid liquid discharge valve is arranged at the bottom of the ozone water tank. When the silicon wafer is used, the silicon wafer is soaked in the ozone water tank and then is drained immediately, and the ozone water is uniformly sprayed from the nozzle to the two sides of the silicon wafer while being drained. Thus, the metal hydroxide complex ions on the silicon wafer are rapidly oxidized into hydroxides in a short time, and the hydroxides are rapidly discharged out of the tank along with the rapidly discharged chemical solution. The structural combination of ozone water spraying and rapid liquid discharge can more effectively prevent the metal hydroxide from being attached to the surface of the silicon wafer again.
The quick drain valve of the present invention is commercially available from ADVANCE electric appliances, Japan, under the model number QDR 125F-V283.
Based on the above, the invention provides a silicon wafer cleaning method, which comprises the following cleaning steps:
A. cleaning the silicon wafer in an SC-1 cleaning tank twice in sequence;
B. ozone water cleaning
B, soaking the silicon wafer cleaned in the step A in an ozone water cleaning tank in a vertical state for 5-7 min, then opening a quick liquid discharge valve at the bottom of the tank to quickly discharge liquid, simultaneously opening two spray pipes above the cleaning tank, uniformly spraying two sides of the silicon wafer by nozzles on the spray pipes, wherein the water spraying pressure of each nozzle is 0.2-0.3 MPa, the flow rate is 2-3 l/min, and the interval between the silicon wafer and the nozzles is 10-15 cm;
C. DIW cleaning, namely, cleaning the silicon wafer cleaned by ozone water in a pure water overflow tank to remove the ozone water attached to the surface of the silicon wafer;
D. HF treatment, namely, putting the silicon wafer treated in the step C into an HF tank for treatment, removing an oxide film on the surface of the silicon wafer, and then putting the silicon wafer into a pure water tank for final cleaning;
E. d, lifting and drying, namely, flowing the silicon wafer washed in the step D into a lifting and drying tank, and slowly lifting and drying the silicon wafer to dry the residual water on the surface under the normal temperature condition.
Preferably, the silicon wafer cleaning method provided by the invention further comprises auxiliary drying, wherein the silicon wafer dried in the step E is dried on the surface of the silicon wafer at the temperature of 60-65 ℃, so that the residual moisture on the surface of the silicon wafer is sufficiently dried.
Preferably, in the silicon wafer cleaning method provided by the invention, in the SC-1 cleaning solution adopted in the step A, NH is added4OH、H2O2And H2The volume ratio of O is 1:2: 10-1: 2: 50.
Preferably, in the silicon wafer cleaning method provided by the invention, in the step B, the concentration of ozone in the ozone water is 1-100 ppm, and the spraying time is more than or equal to 3 minutes.
Preferably, in the silicon wafer cleaning method provided by the invention, in the step B, five nozzles are arranged on each spray pipe, when the shape of the nozzles is fan-shaped, the water spraying pressure is 0.2MPa, when the shape of the nozzles is conical, the water spraying pressure is 0.3MPa, and the water spraying amount of the two spray pipes is 20-30 l/min.
Preferably, in the silicon wafer cleaning method provided by the invention, in the step D, the volume ratio of HF to water is 1: 500-1: 5000.
The invention has the following beneficial guarantee and effects:
the method adopts the steps of soaking in ozone water and spraying after SC-1 cleaning, firstly, the silicon wafer is placed into an ozone water cleaning tank in a vertical state to be soaked for 5-7 min, then a rapid liquid discharge valve at the bottom of the tank is opened to carry out rapid liquid discharge, two spray pipes above the cleaning tank are opened at the same time of liquid discharge, and nozzles on the spray pipes uniformly spray two sides of the silicon wafer at the same time, so that metal hydroxide complex ions on the silicon wafer are rapidly oxidized into hydroxide in a short time, and the hydroxide flows to the bottom of the ozone water cleaning tank under the action of a spraying liquid flow and is rapidly discharged through the rapid liquid discharge valve. The arrangement of the ozone water spray ensures that the hydroxide has no residence time and no reattachment opportunity, thereby realizing the removal of the complex ions of the metal hydroxide.
In addition, the water spraying pressure of each nozzle is 0.2-0.3 MPa, the flow is 2-3 l/min, and the interval between the silicon wafer and the nozzle is 10-15 cm, so that the spraying force applied to the silicon wafer is moderate, the phenomenon that the silicon wafer swings too much due to spraying operation to cause damage to a bracket at the bottom of a groove and the edge of the silicon wafer or foreign matters are generated due to friction is avoided, and the damage to the silicon wafer and the removal of the foreign matters are realized.
Detailed Description
The present invention will now be described in detail with reference to examples, but the practice of the present invention is not limited thereto.
Putting the silicon wafer to be cleaned into a cleaning machine, starting unidirectional flow, and cleaning the silicon wafer from tank to tank according to the following steps, wherein the cleaning flow is shown in table 1:
TABLE 1 silicon wafer cleaning procedure
Groove number | Cleaning method | Using a medicinal liquid |
1 | SC-1 treatment | NH4OH、H2O2 |
2 | SC-1 treatment | NH4OH、H2O2 |
3 | Ozone water treatment | Ozone water |
4 | DIW processing | DIW |
5 | HF treatment | HF |
6 | DIW processing | DIW |
7 | Pulling and drying | ---- |
8 | Assisted drying | ---- |
The washing steps are specifically described as follows:
A. SC-1 cleaning
And cleaning the silicon wafer in an alkaline SC-1 cleaning tank twice to remove metal particle impurities. The adopted SC-1 cleaning solution comprises NH4OH、H2O2And HO2The volume ratio of the three is 1:2: 10-1: 2: 50;
B. ozone water cleaning
And B, vertically placing the silicon wafer cleaned in the step A into an ozone water cleaning tank with the ozone concentration of 1-100 ppm for soaking for 5min, immediately opening a rapid liquid discharge valve at the bottom of the tank to rapidly discharge liquid, and simultaneously opening two spray pipes above the cleaning tank to discharge liquid. The nozzles on the spray pipes simultaneously and uniformly spray the two surfaces of the silicon wafer for at least 3min, the water spraying pressure of each nozzle is 0.2-0.3 MPa, the flow rate is 2-3 l/min, and the interval between the silicon wafer and the nozzle is 10-15 cm.
Each spray pipe is provided with five nozzles, when the shape of the nozzle is fan-shaped, the water spray pressure is 0.2MPa, and when the shape of the nozzle is conical, the water spray pressure is 0.3 MPa. The spraying water amount of the two spray pipes is 20-30 l/min. The jet flow velocity does not cause the silicon wafer to swing too much, so that the groove bottom bracket and the edge of the silicon wafer are scratched or foreign matters are generated due to friction.
Regarding the ozone water tank used in the present embodiment, improvement was made on the ozone water tank used in the conventional overflow: two spray pipes with nozzles are arranged above the tank and are respectively arranged at two sides of the silicon wafer, a rapid liquid discharge valve is arranged at the bottom of the tank, and an ozone water storage structure is arranged inside the tank. The quick drain valve was purchased from ADVANCE Electrical industries, Inc. of Japan, and has a model number of QDR 125F-V283.
C. And (3) DIW cleaning, namely, cleaning the silicon wafer cleaned by the ozone water in a pure water overflow trough to remove the ozone water attached to the surface of the silicon wafer.
D. And D, HF treatment, namely putting the silicon wafer treated in the step C into an HF tank with the concentration of HF being 1: 500-1: 5000 for treatment, removing an oxide film on the surface of the silicon wafer, and then putting the silicon wafer into a pure water tank for final cleaning.
E. D, lifting and drying, namely, flowing the silicon wafer washed in the step D into a lifting and drying tank, and slowly lifting and drying the silicon wafer to dry the residual water on the surface under the normal temperature condition.
F. And E, auxiliary drying, namely drying the silicon wafer dried in the step E at the temperature of 60-65 ℃ to fully dry the residual moisture on the surface of the silicon wafer.
After the above-mentioned treatment steps, the dried silicon wafer is automatically carried out of the cleaning machine, and the whole cleaning process is finished.
In this embodiment, the ozone water spray tank is disposed behind the SC-1 alkaline chemical treatment tank, and the pure water overflow tank is not disposed between the two tanks. The metal hydroxide complex ions on the silicon wafer are quickly oxidized into hydroxide in a short time by spraying, and the hydroxide flows to the bottom of the ozone water cleaning tank under the action of spraying liquid flow and is quickly discharged through a quick liquid discharge valve. The arrangement of the ozone water spray ensures that the hydroxide has no residence time and no reattachment opportunity, thereby realizing the removal of the complex ions of the metal hydroxide.
While the preferred embodiments of the present invention have been described in detail, it will be understood by those skilled in the art that the invention is not limited thereto, and that various changes and modifications may be made without departing from the spirit of the invention, and the scope of the appended claims is to be accorded the full scope of the invention.
Claims (6)
1. A silicon wafer cleaning method comprises A, SC-1 cleaning step, wherein the silicon wafer is cleaned in an SC-1 cleaning tank twice, and the method is characterized by also comprising the following steps:
B. ozone water cleaning
B, soaking the silicon wafer cleaned in the step A in an ozone water cleaning tank in a vertical state for 5-7 min, then opening a quick liquid discharge valve at the bottom of the tank to quickly discharge liquid, simultaneously opening two spray pipes above the cleaning tank, uniformly spraying two sides of the silicon wafer by nozzles on the spray pipes, wherein the water spraying pressure of each nozzle is 0.2-0.3 MPa, the flow rate is 2-3 l/min, and the interval between the silicon wafer and the nozzles is 10-15 cm;
C. DIW cleaning
Putting the silicon wafer cleaned by the ozone water into a pure water overflow trough for cleaning, and removing the ozone water attached to the surface of the silicon wafer;
D. HF treatment
C, placing the silicon wafer processed in the step C into an HF tank for processing, removing an oxide film on the surface of the silicon wafer, and then placing the silicon wafer into a pure water tank for final cleaning;
E. pulling and drying
And D, flowing the silicon wafer after the washing treatment in the step D into a pulling drying tank, and slowly pulling the silicon wafer to dry the residual water on the surface under the normal temperature condition.
2. The method for cleaning a silicon wafer according to claim 1, further comprising:
and E, auxiliary drying, namely drying the surface of the silicon wafer dried in the step E at the temperature of 60-65 ℃.
3. The silicon wafer cleaning method according to claim 1, characterized in that:
wherein, in the SC-1 cleaning solution adopted in the step A, NH is contained4OH、H2O2And H2The volume ratio of O is 1:2: 10-1: 2: 50.
4. The silicon wafer cleaning method according to claim 1, characterized in that:
wherein in the step B, the concentration of ozone in the ozone water is 1-100 ppm, and the spraying time is more than or equal to 3 minutes.
5. The silicon wafer cleaning method according to claim 1, characterized in that:
in the step B, five nozzles are arranged on each spray pipe, when the shape of each nozzle is a fan shape, the water spraying pressure is 0.2MPa, when the shape of each nozzle is a cone shape, the water spraying pressure is 0.3MPa, and the water spraying amount of the two spray pipes is 20-30 l/min.
6. The silicon wafer cleaning method according to claim 1, characterized in that:
in the step D, the volume ratio of HF to water is 1: 500-1: 5000.
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CN111199874A (en) * | 2020-01-13 | 2020-05-26 | 天津中环领先材料技术有限公司 | Silicon wafer cleaning process |
CN112928017A (en) * | 2021-04-02 | 2021-06-08 | 杭州中欣晶圆半导体股份有限公司 | Cleaning method for effectively removing metal on surface of silicon wafer |
CN113394134B (en) * | 2021-05-11 | 2022-10-25 | 桂林芯隆科技有限公司 | Automatic liquid spraying device and method for chip scribing |
CN113736580A (en) * | 2021-09-03 | 2021-12-03 | 上海中欣晶圆半导体科技有限公司 | Mixed acid cleaning solution for cleaning and polishing silicon wafer and cleaning method for polished silicon wafer |
CN116651842A (en) * | 2022-02-17 | 2023-08-29 | 上海超硅半导体股份有限公司 | A kind of wafer material cleaning method |
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JP2002100599A (en) * | 2000-09-21 | 2002-04-05 | Mitsubishi Materials Silicon Corp | Washing method for silicon wafer |
TWI233168B (en) * | 2003-09-01 | 2005-05-21 | Macronix Int Co Ltd | Method of cleaning surface of wafer by hydroxyl radical of deionized water |
JP2007150164A (en) * | 2005-11-30 | 2007-06-14 | Renesas Technology Corp | Substrate washing method |
CN102064090B (en) * | 2010-10-15 | 2013-01-09 | 北京通美晶体技术有限公司 | Method for cleaning compound semiconductor chip |
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