Fluorine etching equipment based on non-plasma
By designing a non-plasma-based fluorine etching device, the existing technology cannot meet the demands of high-capacity photovoltaic cell production, realize high-efficiency etching and continuous processing of large-size silicon wafers, improve production efficiency and reduce production efficiency The cost.
Patent Information
- Application Number
- CN202411312054.1
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2024-09-20
- Publication Date
- 2025-02-18
AI Technical Summary
The existing silicon etching devices based on fluorine-containing gases such as XeF2 can only etch silicon wafers with a maximum diameter of less than 100mm, and cannot meet the needs of high-capacity photovoltaic cell production.
A non-plasmon-based fluorine etching device is designed, including a housing, a first isolation cavity, a process cavity, a second isolation cavity and a feeding and transfer mechanism, so as to achieve precise control of the silicon wafer by vacuuming and preheating treatment and Continuous processing.
It realizes efficient etching of silicon wafers, improves production efficiency, can handle large-size silicon structures, and the total process time is between tens of seconds and minutes, reducing the production cost of photovoltaic cell cells.
Smart Images
Figure CN119480690A_ABST
Abstract
Description
Technical Field
[0001] The invention relates to the field of photovoltaic equipment and semiconductor technology, and in particular to a non-plasma-based fluorine etching device. Background Art
[0002] In the field of photovoltaic device technology and semiconductor technology, it is often necessary to perform various etchings of silicon substrates with precise dimensions, with etchants ranging from liquid etchants (such as ethylenediamine catechol and KOH) to high-energy plasma etchants based on Cl2 or SF6 gas. These etching agents can provide great flexibility and controllability in the manufacture of precisely defined microstructures, but have limitations on use due to limited selectivity for general materials (such as photoresists or oxides) that are usually used as mask layers in etching processes.
[0003] Non-plasma silicon etchants such as XeF2, BrF3, and BrF5 have high selectivity for photoresists, silicon oxides, silicon nitrides, or aluminum layers, and can etch silicon in the gas phase. In addition, due to the isotropic etching characteristics and high etching rates of several μm / min, this etching method can quickly etch the surface of large-scale silicon structures, and the etching reaction products can be removed by the vacuum system, with basically no etching pollution.
[0004] Conventional silicon etching equipment based on fluorine-containing gases such as XeF2 can only etch silicon wafers with a maximum diameter of less than 100mm, and the processing capacity per batch is 1 wafer, which is only suitable for etching MEMS devices. For the current photovoltaic cell production that requires high production capacity (>8000 wafers / h), conventional fluorine etching equipment is completely unsatisfactory. Therefore, it is urgent to develop non-plasma-based fluorine etching equipment to improve production efficiency and reduce the production cost of photovoltaic cells. Summary of the invention
[0005] The object of the present invention is to provide a non-plasma based fluorine etching device to solve the problems existing in the above-mentioned prior art.
[0006] To achieve the above-mentioned purpose, the present invention provides a non-plasma-based fluorine etching device, including a shell, wherein a first isolation chamber, a process chamber, a second isolation chamber and a loading and conveying mechanism are arranged inside the shell; the first isolation chamber is used to perform pre-etching pretreatment on silicon wafers, wherein the pre-etching pretreatment includes vacuum treatment and preheating treatment; the process chamber is used for the etching reaction of the silicon wafer; the second isolation chamber is used to isolate the silicon wafer after the etching reaction; the loading and conveying mechanism is used to transport the silicon wafer, and the loading and conveying mechanism is connected to the first isolation chamber, the process chamber and the second isolation chamber in sequence; the shell is connected to a protective gas purge device and a vacuum device, the protective gas purge device is used to eliminate air moisture in the shell, and the vacuum device is used to achieve a low-pressure environment inside the shell.
[0007] Preferably, the vacuuming treatment in the pre-etching pretreatment is achieved by the vacuuming device, the first isolation chamber is equipped with a heating device, and the preheating treatment in the pre-etching pretreatment is achieved by the heating device.
[0008] Preferably, after the vacuum treatment, the internal pressure of the first isolation chamber is 0.1Pa-300Pa; when the preheating treatment is performed, the preheating temperature is 50℃-300℃; the heating method of the heating device is one or more of induction heating and / or infrared heating and / or hot air circulation.
[0009] Preferably, the internal pressure of the process chamber is not greater than the internal pressure of the first isolation chamber, and the pressure difference between the two is 0-100 Pa; the internal temperature of the process chamber is 80°C-260°C.
[0010] Preferably, the second isolation chamber is connected to the protective gas purging device, and after the silicon wafer after the etching reaction enters the second isolation chamber, the protective gas purging device is used to purge the second isolation chamber with protective gas.
[0011] Preferably, the second isolation chamber is communicated with the vacuum pumping device, and after the silicon wafer after the etching reaction enters the second isolation chamber, the vacuum pumping device is used to evacuate the second isolation chamber.
[0012] Preferably, the loading and transporting mechanism comprises at least one transport track, and the transport track is used to connect the first isolation chamber, the process chamber and the second isolation chamber; a carrier is arranged on the transport track, and the silicon wafer is loaded through the carrier.
[0013] Preferably, the inner wall of the process chamber, the surface of the transfer track, and the surface of the carrier are all coated with a fluorine-resistant coating, and the fluorine-resistant coating is one of aluminum oxide, nickel, polytetrafluoroethylene, tetrafluoroethylene-perfluoroalkoxy ether copolymer, fluorinated ethylene propylene, ethylene and tetrafluoroethylene copolymer, and ethylene and chlorotrifluoroethylene polymer.
[0014] Preferably, the number of the first isolation chambers is not less than one, and the distances between the first isolation chambers and the process chambers are the same.
[0015] Preferably, the number of the process chambers is not less than one, and the process chambers are arranged in series on the loading and conveying mechanism.
[0016] Compared with the prior art, the present invention has the following advantages and technical effects:
[0017] The non-plasma-based fluorine etching equipment provided by the present invention facilitates accurate control of silicon wafer processing and batch continuous processing of silicon wafers through the design of mutually isolated chambers. The entire process basically has no pause, waiting or buffering process. The total duration of the entire process is between tens of seconds and several minutes, which greatly improves production efficiency. Since a large chamber design can be adopted, a larger wafer loading capacity can be achieved. BRIEF DESCRIPTION OF THE DRAWINGS
[0018] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.
[0019] Figure 1 It is a schematic structural diagram of the fluorine etching device of the present invention when each cavity is an independent cavity;
[0020] Figure 2 This is a schematic structural diagram of the fluorine etching equipment of the present invention when the same cavity is divided into individual cavities by an isolation valve;
[0021] Figure 3 It is a schematic structural diagram of the fluorine etching equipment of the present invention when it includes multiple process chambers;
[0022] Figure 4 It is a schematic structural diagram of the fluorine etching device of the present invention when it includes a plurality of first isolation chambers and second isolation chambers;
[0023] In the figure: 1. Shell; 2. First isolation chamber; 3. Process chamber; 4. Second isolation chamber; 5. Transmission track; 6. Isolation valve. DETAILED DESCRIPTION
[0024] It should be noted that, in the absence of conflict, the embodiments of the present invention and the features in the embodiments can be combined with each other. The described embodiments are only some embodiments of the present invention, not all embodiments. All other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention. The present invention will be described in detail below with reference to the drawings and in combination with the embodiments.
[0025] The present invention provides a non-plasma-based fluorine etching device, comprising a shell 1, wherein a first isolation chamber 2, a process chamber 3, a second isolation chamber 4 and a feeding and conveying mechanism are arranged inside the shell 1; the first isolation chamber 2 is used for pre-etching pretreatment of silicon wafers, wherein the pre-etching pretreatment includes vacuum treatment and preheating treatment; the process chamber 3 is used for etching reaction of silicon wafers, and the reaction time is 3 seconds to 30 minutes; the second isolation chamber 4 is used for discharging and isolating silicon wafers after etching reaction; the feeding and conveying mechanism is used for conveying silicon wafers, and the feeding and conveying mechanism is sequentially connected to the first isolation chamber 2, the process chamber 3 and The second isolation chamber 4; the shell 1 is connected to a protective gas purge device and a vacuum device, the protective gas purge device is used to eliminate the air moisture in the shell 1, so as to prevent the air moisture from reacting with the process gas introduced later to form HF, and the process gas is a fluorine-containing gas such as XeF2, BrF3, BrF5, IF5, CIF3, etc.; the removal of HF increases the selectivity of silicon to the mask oxide layer to more than 2000:1, so as to reduce the damage to the profile of the mask oxide layer, thereby realizing a long time and precise size etching process; the vacuum device is used to realize a low-pressure environment inside the shell 1.
[0026] Furthermore, the first isolation chamber 2, the process chamber 3 and the second isolation chamber 4 can be independent chambers separated from each other; or they can be different areas located in the same chamber, and adjacent areas are separated by isolation valves 6 or other means, thereby forming the first isolation chamber 2, the process chamber 3 and the second isolation chamber 4.
[0027] Furthermore, the vacuum treatment in the pretreatment before etching is achieved by a vacuum treatment device. After the vacuum treatment, the internal pressure of the first isolation chamber 2 is 0.1Pa-300Pa; the first isolation chamber 2 is equipped with a heating device, and the preheating treatment in the pretreatment before etching is achieved by the heating device. The silicon wafer transferred into the first isolation chamber 2 is preheated to the temperature required by the process, and it can react quickly after entering the process chamber 3. During the preheating treatment, the preheating temperature is 50℃-300℃; the heating method of the heating device is one or more of induction heating and / or infrared heating and / or hot air circulation.
[0028] Furthermore, the internal pressure of the process chamber 3 is not greater than the internal pressure of the first isolation chamber 2, and the pressure difference between the two is 0-100Pa, which can prevent the process gas from leaking out; the internal temperature of the process chamber 3 is 80℃-260℃.
[0029] Furthermore, in order to prevent the process gas and gas products from leaking into the atmosphere when the silicon wafer is removed, one solution is: the second isolation chamber 4 is connected to the protective gas purging device, and after the silicon wafer after the etching reaction enters the second isolation chamber 4, the second isolation chamber 4 is sealed, and the protective gas purging device is used to purge the second isolation chamber 4 with protective gas to remove the reaction products on the surface of the silicon wafer and the process gas brought into the second isolation chamber 4, thereby preventing the process gas and gas products from leaking into the atmosphere when the silicon wafer is removed, and after a certain period of time when the air pressure in the second isolation chamber 4 is substantially the same as the external atmospheric pressure, the silicon wafer is removed and unloaded. Another solution is: the second isolation chamber 4 is connected to the vacuum pumping device, and after the silicon wafer after the etching reaction enters the second isolation chamber 4, the second isolation chamber 4 is sealed, and the vacuum pumping device is used to evacuate the second isolation chamber 4 to extract the process gas and gas products brought into the second isolation chamber 4, and then nitrogen, air or other gases are injected to make the air pressure substantially the same as the external atmospheric pressure, and then the silicon wafer is removed and unloaded.
[0030] Furthermore, a cooling device is provided in the second isolation chamber 4 to cool down the silicon wafer and the carrier before the silicon wafer is moved out of the second isolation chamber 4, and the cooling mechanism adopts air cooling.
[0031] Furthermore, the loading and transporting mechanism includes at least one transport track 5, which is used to connect the first isolation chamber 2, the process chamber 3 and the second isolation chamber 4; a carrier is arranged on the transport track 5, and the silicon wafers are loaded through the carrier. The carrier can be a basket, a tray, or a boat, and the carrier has a one-layer or multi-layer structure, and the silicon wafers are stacked or laid flat. During the transmission, the surface of the silicon wafer is parallel or perpendicular to the transmission direction; the silicon wafer is transported from the first isolation chamber 2 to the process chamber 3 and from the process chamber 3 to the second isolation chamber 4 under vacuum or low pressure conditions.
[0032] Furthermore, more than one of the first isolation chamber 2, the process chamber 3, and the second isolation chamber 4 can be set. When the process time of the first isolation chamber 2 is greater than the process time in the process chamber 3, multiple first isolation chambers 2 are set for pre-etching pretreatment of silicon wafers, and the process chamber 3 is immediately entered into after the treatment is completed, thereby reducing the waiting time of the process chamber 3; the distances between multiple first isolation chambers 2 and the process chamber 3 are the same to ensure that the time to enter the process chamber 3 is similar, thereby improving the process control accuracy. When the process time of the first isolation chamber 2 is less than the process time in the process chamber 3, multiple process chambers 3 arranged in series can be set, and each process chamber 3 performs a partial thickness of the total etching reaction, thereby avoiding ineffective waiting of silicon wafers at the first isolation chamber 2 station, and realizing continuous operation of the process, thereby improving production efficiency.
[0033] Furthermore, the inner wall of the process chamber 3, the surface of the transfer track 5, and the surface of the carrier are coated with a fluorine-resistant coating, and the fluorine-resistant coating is one of aluminum oxide, nickel, polytetrafluoroethylene, tetrafluoroethylene-perfluoroalkoxy ether copolymer, fluorinated ethylene propylene, ethylene and tetrafluoroethylene copolymer, and ethylene and chlorotrifluoroethylene polymer.
[0034] According to the reaction principle and process characteristics of fluorine etching, the present invention designs the fluorine etching equipment into cavities with different functions, and the loading and transmission mechanism connects these different cavities. The loading and isolation of silicon wafers are carried out in the first isolation chamber 2, and the environmental pressure of the silicon wafers is changed from atmospheric pressure to the low-pressure environment required for the process reaction. After being purged and heated, the silicon wafers enter the process chamber 3 for reactive etching. The etched silicon wafers enter the second isolation chamber 4 for unloading and isolation, including purging and cooling the surface of the silicon wafers. The silicon wafers are removed after the environmental pressure becomes atmospheric pressure, thereby completing the surface etching of the silicon wafers.
[0035] The isolated chamber design of the present invention facilitates the precise control of silicon wafer processing and the continuous batch processing of silicon wafers. The whole process basically does not require any waiting or buffering. The total duration of the entire process is between tens of seconds and several minutes, which greatly improves production efficiency. Since a large chamber design can be used, a larger wafer loading capacity can be achieved.
[0036] The above are only preferred specific implementations of the present application, but the protection scope of the present application is not limited thereto. Any changes or substitutions that can be easily thought of by a person skilled in the art within the technical scope disclosed in the present application should be included in the protection scope of the present application. Therefore, the protection scope of the present application should be based on the protection scope of the claims.
Claims
1. A non-plasma based fluorine etching device, characterized in that: The invention comprises a shell (1), wherein a first isolation chamber (2), a process chamber (3), a second isolation chamber (4) and a loading and conveying mechanism are arranged inside the shell (1); the first isolation chamber (2) is used for pre-processing silicon wafers before etching, wherein the pre-processing before etching includes vacuum treatment and preheating treatment; the process chamber (3) is used for etching reaction of the silicon wafers; the second isolation chamber (4) is used for discharging and isolating the silicon wafers after the etching reaction; the loading and conveying mechanism is used for conveying the silicon wafers, and the loading and conveying mechanism is connected to the first isolation chamber (2), the process chamber (3) and the second isolation chamber (4) in sequence; the shell (1) is connected to a protective gas purging device and a vacuum device, wherein the protective gas purging device is used to eliminate air moisture in the shell (1), and the vacuum device is used to achieve a low-pressure environment inside the shell (1).
2. The non-plasma based fluorine etching apparatus according to claim 1, characterized in that: The vacuuming treatment in the pre-etching pre-treatment is achieved by the vacuuming device, and the first isolation chamber (2) is equipped with a heating device, and the preheating treatment in the pre-etching pre-treatment is achieved by the heating device.
3. The non-plasma based fluorine etching equipment according to claim 2, characterized in that: After the vacuum treatment, the internal pressure of the first isolation chamber (2) is 0.1Pa-300Pa; when the preheating treatment is performed, the preheating temperature is 50°C-300°C; the heating method of the heating device is one or more of induction heating and / or infrared heating and / or hot air circulation.
4. The non-plasma based fluorine etching apparatus according to claim 1, characterized in that: The internal pressure of the process chamber (3) is not greater than the internal pressure of the first isolation chamber (2), and the pressure difference between the two is 0-100 Pa; the internal temperature of the process chamber (3) is 80° C.-260° C.
5. The non-plasma based fluorine etching apparatus according to claim 1, characterized in that: The second isolation chamber (4) is connected to the protective gas purging device, and after the silicon wafer after the etching reaction enters the second isolation chamber (4), the protective gas purging device is used to purge the second isolation chamber (4) with protective gas.
6. The non-plasma based fluorine etching apparatus according to claim 1, characterized in that: The second isolation chamber (4) is connected to the vacuum pumping device, and after the silicon wafer enters the second isolation chamber (4) after the etching reaction, the second isolation chamber (4) is vacuumed by the vacuum pumping device.
7. The non-plasma based fluorine etching apparatus according to claim 1, characterized in that: The loading and transporting mechanism comprises at least one transport track (5), wherein the transport track (5) is used to connect the first isolation chamber (2), the process chamber (3) and the second isolation chamber (4); a carrier is arranged on the transport track (5), and the silicon wafer is loaded via the carrier.
8. The non-plasma based fluorine etching apparatus according to claim 7, characterized in that: The inner wall of the process chamber (3), the surface of the transfer track (5), and the surface of the carrier are all coated with a fluorine-resistant coating, and the fluorine-resistant coating is one of aluminum oxide, nickel, polytetrafluoroethylene, tetrafluoroethylene-perfluoroalkoxy ether copolymer, fluorinated ethylene propylene, ethylene and tetrafluoroethylene copolymer, and ethylene and chlorotrifluoroethylene polymer.
9. The non-plasma based fluorine etching apparatus according to claim 1, characterized in that: The number of the first isolation chamber (2) is not less than one, and the distances between the first isolation chamber (2) and the process chamber (3) are the same.
10. The non-plasma based fluorine etching apparatus according to claim 1, characterized in that: The number of the process chambers (3) is not less than one, and the process chambers (3) are arranged in series on the loading and conveying mechanism.