TW500832B - Method for preventing an electrostatic chuck from corroded during a cleaning process - Google Patents

Abstract

The present invention relates to a method for preventing an electrostatic chuck positioned at the bottom of a plasma vacuum chamber from being corroded during a cleaning process. The electrostatic chuck comprises a conductive substrate functioned as a lower electrode in a plasma process, and an insulating layer on the conductive substrate to electrically isolate the semiconductor wafer and the conductive substrate. The cleaning process involves a plasma process in which a fluorine-contained gas is injected into the plasma vacuum chamber to remove the chemical layer on the inner wall of the plasma vacuum chamber. A ceramic shutter made of SiC material is reposed on the electrostatic chuck and a high DC voltage is applied to the conductive substrate and the ceramic shutter which causes the ceramic shutter and the electrostatic chuck tightly stick together due to an electrostatic reaction. By doing so, the fluorine-contained gas cannot corrode the insulating layer under the ceramic shutter through the gap between the ceramic shutter and the electrostatic chuck.

Description

500832 V. Description of the invention (1) The present invention provides a method for preventing corrosion, especially a method for preventing the electrostatic seat from being corroded during the cleaning process. In semiconductor manufacturing, high-density plasma chemical vapor deposition (HDPCVD) is a thin-film deposition technology that is mainly performed in an electric impeller vacuum chamber (chamber) to allow reactive gases to be deposited on Half body wafer surface. The reaction gas will also adhere to the inside of the plasma real jade cabin to form deposits. Therefore, the general plasma vacuum cabin is equipped with self-cleaning equipment, which can be cleaned in time to improve the yield of the process and extend the life of the cabin. Please refer to FIG. 1, which is a schematic diagram of a conventional electrostatic pedestal 10. The conventional static base 10 is located at the bottom of the plasma vacuum chamber (not shown) for receiving semiconductor wafers. The electrostatic base 10 includes a metal disc 4 for the lower electrode during processing, and an insulating layer 12 covering the surface 'for electrically isolating the semiconductor wafer from the metal disc 14. The surface of the electrostatic base 10 is provided with a plurality of vent holes 17 for cooling semiconductor chip bodies, and a plurality of grooves 18 for guiding a cooling gas (c〇i ^ "gas) 0g during the HDPCVD process. A process sink is formed inside the plasma vacuum chamber. With the increase of the number of times the plasma vacuum chamber is used, the 'reaction gas will also adhere to the electric deposit' and when the thickness of the deposit increases, the thickness will increase to a certain degree.

Page 6 Five-manufacturing, invention description (2) Process sediments 4 Therefore, it must be timely; electricity = grain f p-ticle) source. Due to the lifetime of the cleaning process. -Generally in the vacuum of electropolymerization :: n -1 ^ ^ ^ will pass into the plasma vacuum chamber with a 47% water content, in order to remove dangerous snow and ancient ~ ^ f oxygen gas into the HDPCVD process Anti-shore life】 ς soil: the process of washing in the cabin =. For example, NF ammonia is used as the electric gas ^ H and emulsified silicon. Generally, 10 is used. It is easy to be corroded by the plasma gas in the soil due to the electrostatic seat in the plasma vacuum chamber. Just after the main washing, the protective measures for the electrostatic base 10 must be taken first. b. When entering the lamp, please refer to Figure 2. Figure 2 is a seat that is familiar with the method of being decomposed during cleaning. 1 The side that is decomposed during cleaning is made of alumina (A 1 20 3). In terms of composition, the fluorine-containing surface used to isolate subsequent access is eroded by fluorine ions. However, on the ceramic base 10, fluorine ions can still enter through the gaps in the ceramic edge, and then the static electricity is eroded to prevent the schematic diagram of the electrostatic base 10 shown in Figure 1. The conventional method is used to prevent static electricity. Before cleaning, the ceramic baffle 16 is placed flat on the static seat i 〇 gas to avoid the surface plate 16 of the static stand 10 being placed in a static position by gravity. The outer edge portion of the edge seat 10 of the contact surface between the plate 16 and the insulating layer 12. In a long-term erosion state, the flatness between the outer edge portion and the middle portion of the electrostatic base 10 will produce a great difference, which will cause the outer edge portion of the semiconductor wafer placed on the electrostatic base i 0 to hang, resulting in The outer edge portion of the back surface of the semiconductor wafer is easily contaminated with particles, or the semiconductor wafer cannot be stably fixed on the electrostatic base 10. In addition, during the HDPCVD process,

500832

The air holes 17 on the surface of the electrostatic pedestal 10 will be affected and the smoothness of each area on the surface of the semiconductor wafer cannot be obtained smoothly. The cooling gas sent from the tank 18 is also dispersed to the back of the semiconductor wafer, so that the temperature is inconsistent and affects the entire sink. Therefore, the main purpose of the present invention is to be rotted during the washing process, which can enter the edge gap between the baffle and the electrostatic seat The invention provides a method for preventing the electrostatic pedestal from effectively preventing the fluorine-containing gas from eroding the outer edge of the electrostatic pedestal through the ceramic.

"Cangkao Figure 2" and Figure 3 are schematic diagrams of the method for preventing the electrostatic holder 2 from being rotten in the cleaning process according to the present invention. The invention is a method for preventing an electrostatic base 21 from being leftover during cleaning. The electrostatic base 2 is a circular flat plate, which is located in the bottom of a plasma vacuum chamber 20 for HDPCVD process, and is used for holding a semiconductor wafer (not shown). The electrostatic mount 21 includes a conductive substrate 24, which is used as a lower electrode plate during a plasma deposition process, and a non-conductive insulating layer 22 is provided on the surface of the conductive substrate 24 to isolate Semiconductor wafer and conductive base 24. When a bias voltage is applied to the upper and lower electrode plates, the insulating layer 22 will induce static electricity to attract the semiconductor wafer. The electrostatic base 21 is also shown in the electrostatic base 10 shown in FIG. 2. The surface is provided with a plurality of vent holes for passing in the gas used to cool the semiconductor wafer during the HDPCVD process, and a plurality of grooves arranged in a radial pattern. , Used to guide the cooling gas. The method for preventing the electrostatic base 21 from being corroded in the cleaning process according to the present invention is

Page 8 2 0 Before cleaning, the plate 2 6 is placed on the electrostatic base to completely cover the static electricity. The porcelain baffle 2 6 is applied with an electrical action and tightly adhered. The ceramic baffle 2 6 will be on the electrostatic base 21. Access to the tank 2 0 into a hollow process sediment Description of the invention (4) & plasma vacuum chamber, a ceramic baffle plate, and the electric base 2 4 and the ceramic plate 26 can have a good DC voltage due to the static material At 28 o'clock, it is tightly fixed to the process. For the plasma real body, a dry and plasma process is performed. A silicon carbide (Si C) substrate 21 is used, and the ceramic baffle 26 is a circular shape of a circular base 21. surface. Then, the high voltage DC voltage 2 8 is conducted to make the ceramics block the surface of the electrostatic base 21. Because of the carbonization and electrical conductivity, when a high voltage is applied and it is adsorbed by the induced electrostatic force, it can begin to clean the fluorine (F) nitrogen trifluoride (liver 3 > gas' to remove the inner wall of the plasma vacuum chamber 20 due to Ceramic baffle 2 6 蘩 宓 λα η ^ gas must not pass through Tao Jing; ί = = fixed on the electrostatic base 21, so that it must be contained under the ceramic bidding board 26 '绝 ^ and the electrostatic base 21 Erosion will be corroded by the plasma gas, so the flatness of the outer edge portion of the electrostatic base 21 is kept the same. Make ^ = make the outer edge of the electrostatic base 21 and the middle part prevent the electrostatic base 21 from being cleaned, 焉 ^ Inventing the method for cleaning can prevent the tablet from being left flat because it cannot be laid flat in the static species, thereby avoiding the situation where the semiconductor 1 is suspended. Compared to the conventional method to prevent static respect

Method, the present invention prevents static electricity = the base 10 is corroded during the cleaning process by a method with a good squeeze ^ ^ 1 is corroded during the cleaning process, the plate 2 6 completely covers the electrostatic base 2 And conductive silicon carbide ceramic stopper 'and apply high voltage DC voltage 2 8 to make the ceramic

500S32 V. Description of the invention (5) The baffle 26 is closely attached to the surface of the electrostatic base 21 due to the electrostatic effect, to avoid any gap between the ceramics 2 and the electrostatic base 21. Therefore, during the cleaning process, the gas of the two gases must not erode the M edge layer 2 2 through the gap between the ceramic baffle 2 β and the electrostatic base 21, which can prevent the outer edge of the electrostatic base 21 from being corroded by the plasma gas and affect its surface. Flatness.

Page 10 500832 Simple description of the garden. Simple illustration of the diagram. The corrosion and cleaning of the equations in the French method are electrostatically washed in the middle seat. The clear picture shows the static electricity of the electric picture in a block. Stopping electricity to prevent static electricity means to use knowledge to show the basic principles of the practice. No. I Two-Party-Three-Characters Symbols and Diagrams of the Diagram Meaning #Illustrated Rotten Diagrams 20 Plasma Vacuum Chamber 21 Electrostatic Block 22 Insulating Layer 24 Conductive Base 26 Ceramic Bezel 28 High Voltage DC Voltage

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Claims (1)

500832 2ί 6. Applying for a special method to prevent an electrostatic base from being corroded during the cleaning process. The electrostatic base is a circular flat plate used to hold a semiconductor wafer and leased to one. The bottom of the plasma chamber of the high density tfpiasma chenucal vapor deposition (HDpcVD) process contains a conductive base (conductor, substrate) for performing a plasma During the manufacturing process, the lower electrode and two insulating layers are provided on the surface of the conductive base to electrically isolate the semiconductor wafer from the conductive base. The cleaning process will pass a gas containing fluorine (F) to the plasma vacuum chamber. A plasma process is performed to remove the process deposits on the inner wall of the plasma vacuum chamber. The method includes: 2. In the cleaning process, a circular ceramic baffle plate is placed on the The surface of the electrostatic base, and the ceramic baffle plate can completely cover the circular surface of the electrostatic base, and a direct current voltage is applied to the conductive base and the ceramic baffle plate. Closely adhere to the surface of the electrostatic pedestal, so that the fluorine-containing gas must not erode the insulating layer under the ceramic pedestal through the gap between the ceramic pedestal and the electrostatic pedestal. The surface of the seat is provided with a plurality of ventilation holes for introducing a gas for cooling the semiconductor wafer in a plasma process, and a plurality of grooves arranged in a radial pattern for guiding the cooling gas. . ^ The method described in patent scope 1, wherein the fluorine-containing gas system is nitrogen fluoride (NF3h Page 12