KR-102962414-B1 - Method of processing substrate

KR102962414B1KR 102962414 B1KR102962414 B1KR 102962414B1KR-102962414-B1

Abstract

A method for processing a substrate using a substrate processing apparatus comprising: a process chamber having a reaction space formed therein for processing a substrate having a second thin film formed on top of a first thin film; a substrate support member coupled to the process chamber to support the substrate; a gas injection member coupled to the upper part of the process chamber to face the substrate support member; and a plasma reactor disposed outside the process chamber and connected to the gas injection member, the method comprising: a step of preparing the substrate in the reaction space; and an etching step of etching the first thin film relative to the second thin film on the substrate, wherein the first thin film is a polysilicon film and the second thin film is a stacked thin film of a silicon nitride film and a silicon oxide film, and in the etching step, the first thin film is etched through a reaction product formed by the reaction of a first process gas containing NF3 gas and a second process gas containing NH3 gas, wherein the process temperature during the etching step is greater than 70°C and less than 110°C, and the ratio of the flow rate of the first process gas to the flow rate of the second process gas is 0.5 to 1.0.

Inventors

신소명
조병철
김민수

Assignees

주식회사 원익아이피에스

Dates

Publication Date: 20260511
Application Date: 20230807

Claims (15)

A method for processing a substrate using a substrate processing apparatus comprising: a process chamber having a reaction space formed therein for processing a substrate having a second thin film formed on top of a first thin film; a substrate support member coupled to the process chamber to support the substrate; a gas injection member coupled to the upper part of the process chamber to face the substrate support member; and a remote plasma reactor disposed outside the process chamber and connected to the gas injection member. The method comprises: a step of preparing the substrate within the reaction space; a step of supplying and activating a first process gas containing halogen to the remote plasma reactor to generate radicals and discharging the first process gas containing the radicals in the direction of the gas injection unit; a step of supplying a second process gas containing hydrogen to the first process gas after the first process gas containing the radicals is discharged from the remote plasma reactor and before it reaches the substrate; and an etching step of etching the first thin film relative to the second thin film on the substrate, wherein The first thin film is etched in the above etching step through a reaction product formed by the reaction of the first process gas containing the halogen and the second process gas containing the hydrogen, and the process temperature during the etching step is set such that the etching rate of the first thin film is higher than the etching rate of the second thin film being etched through the reaction product at the above process temperature. Substrate processing method.
In Article 1, The first thin film comprises a polysilicon film, and the second thin film comprises at least one of a silicon nitride film and a silicon oxide film. Substrate processing method.
In Article 2, The second thin film above is a stacked thin film in which silicon nitride films and silicon oxide films are alternately stacked, and Characterized by the process temperature during the above etching step being greater than 70℃ and less than 110℃, Substrate processing method.
In Article 2, The second thin film above is a silicon nitride film, and Characterized by the process temperature during the above etching step being less than 110℃, Substrate processing method.
In Article 2, The second thin film above is a silicon oxide film, and Characterized by the process temperature during the above etching step being greater than 70℃, Substrate processing method.
In Article 1, Characterized that the ratio of the flow rate of the first process gas supplied to the substrate in the above etching step to the flow rate of the second process gas is 0.5 to 1.0. Substrate processing method.
In Article 1, The first process gas containing the halogen is NF3 , and the second process gas containing hydrogen is NH3 , Substrate processing method.
In Article 7, The first process gas further comprises an inert gas, wherein the inert gas is at least one of Ar, H₂ , He, and N₂ . Substrate processing method.
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In Article 1, In the above discharge step, the first process gas containing the radical is supplied to the gas injection unit through a connecting pipe connecting the plasma reactor and the gas injection unit, and In the step of supplying the second process gas, the second process gas is supplied to the first process gas containing the radicals flowing into the connecting pipe through a side pipe connected in the middle of the connecting pipe. Substrate processing method.
In Article 1, In the above discharge step, the first process gas containing the radical is supplied to the gas injection unit through a connecting pipe connecting the plasma reactor and the gas injection unit, and In the step of supplying the second process gas, the second process gas is supplied to the first process gas containing the radical within the gas injection unit through an additional pipe connected to the gas injection unit separately from the connecting pipe. Substrate processing method.
In Article 1, In the above discharge step, the first process gas containing the radical is supplied to the gas injection unit through a connecting pipe connecting the plasma reactor and the gas injection unit, and In the step of supplying the second process gas, the second process gas is supplied to the first process gas containing the radical supplied into the process chamber through the gas injection unit via an additional pipe connected to the process chamber separately from the connecting pipe, Substrate processing method.
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In Article 1, The reactant formed by the reaction of the first process gas containing the halogen and the second process gas containing hydrogen comprises an ammonium fluoride ( NH₃ (HF) ₆ ) reactant. Substrate processing method.
A method for processing a substrate using a substrate processing apparatus comprising: a process chamber having a reaction space formed therein for processing a substrate having a second thin film formed on top of a first thin film; a substrate support member coupled to the process chamber to support the substrate; a gas injection member coupled to the upper part of the process chamber to face the substrate support member; and a remote plasma reactor disposed outside the process chamber and connected to the gas injection member. The method comprises: a step of preparing the substrate within the reaction space; a step of supplying and activating a first process gas containing NF3 gas to the remote plasma reactor to generate radicals and discharging the first process gas containing the radicals in the direction of the gas injection unit; a step of supplying a second process gas containing NH3 gas to the first process gas after the first process gas containing the radicals is discharged from the remote plasma reactor and before it reaches the substrate; and an etching step of etching the first thin film relative to the second thin film on the substrate, wherein The first thin film is a polysilicon film, and the second thin film is a stacked thin film of a silicon nitride film and a silicon oxide film. In the above etching step, the first thin film is etched using a reaction product formed by the reaction of a first process gas containing NF3 gas and a second process gas containing NH3 gas, wherein the process temperature during the etching step is greater than 70℃ and less than 110℃, and the ratio of the flow rate of the first process gas to the flow rate of the second process gas is 0.5 to 1.0. Substrate processing method.

Description

Method of processing substrate The present invention relates to semiconductor manufacturing, and more specifically, to a substrate processing method using a substrate processing apparatus. To manufacture semiconductor devices, various processes are performed in a substrate processing apparatus under a vacuum atmosphere. For example, a substrate may be loaded into a process chamber, and processes such as depositing a thin film or etching a thin film on the substrate may be carried out. Here, the substrate is supported by a substrate support installed within the process chamber, and the substrate can be processed by injecting process gas onto the substrate through a gas injection unit installed on the upper part of the substrate support. Meanwhile, when one or more thin film patterns are formed on the substrate, multiple thin films may be exposed on the substrate. For example, insulating films such as polysilicon films, oxide films, and nitride films may be exposed on the substrate. Subsequently, a process of selectively etching one of these insulating films may be added. Recently, due to the high integration of semiconductor devices, the thickness of these insulating films has decreased, leading to a problem where unwanted insulating films are etched due to a lack of selectivity during the etching step. Furthermore, as the thickness of the insulating film decreases, it becomes difficult for the etching solution to penetrate, thereby limiting conventional wet etching. Dry etching using halide-based etching gases is being researched, but there is a problem in that the etching selectivity is not high. For example, in the stacked configuration of silicon oxide, silicon nitride, and polysilicon in next-generation VNAND devices, selective etching of the polysilicon film is required. In silicon oxide/polysilicon configurations, there is a commercially available method to remove the polysilicon film using a hydrochloric acid solution. However, in configurations where a silicon nitride film is also present, damage to the silicon nitride film cannot be avoided when applying the hydrochloric acid method. FIG. 1 is a schematic diagram showing a substrate processing apparatus for explaining a substrate processing method according to some embodiments of the present invention. FIG. 2 is a flowchart showing a substrate processing method according to some embodiments of the present invention. FIGS. 3 and 4 are schematic cross-sectional views of a substrate showing a substrate processing method according to some embodiments of the present invention. Figure 5 is a diagram showing the results of analyzing the reaction product formed by the reaction of NF3 gas and NH3 gas using a gas analyzer (RGA). Figure 6 is a graph showing the etching behavior of silicon nitride films and silicon oxide films according to heater temperature in a substrate treatment method using ammonium fluoride (NH₃( HF)₆ ) reactant. Figure 7 is a graph comparing the etching rates of silicon nitride, silicon oxide, and polysilicon films. Figure 8 is a graph comparing the etching rates of silicon nitride, silicon oxide, and polysilicon films according to process temperature. Figure 9 is a graph showing the etching rate of a silicon nitride film according to heater temperature. Figure 10 is a graph comparing the etching rates of silicon nitride, silicon oxide, and polysilicon films according to the ratio of the supply flow rate of NF3 gas to the supply flow rate of NH3 gas. FIGS. 11 and FIGS. 12 are schematic diagrams showing substrate processing apparatuses for explaining a substrate processing method according to some other embodiments of the present invention. Hereinafter, several preferred embodiments of the present invention will be described in detail with reference to the attached drawings. The embodiments of the present invention are provided to more fully explain the invention to those skilled in the art, and the following embodiments may be modified in various different forms, and the scope of the invention is not limited to the following embodiments. Rather, these embodiments are provided to make the disclosure more faithful and complete and to fully convey the spirit of the invention to those skilled in the art. In addition, the thickness or size of each layer in the drawings is exaggerated for convenience and clarity of explanation. FIG. 1 is a schematic diagram showing a substrate processing apparatus (100) for explaining a substrate processing method according to some embodiments of the present invention. Referring to FIG. 1, the substrate processing device (100) may include a process chamber (110), a gas injection unit (120), a substrate support unit (130), and a plasma reactor (150). More specifically, a reaction space (112) in which a substrate (S) can be processed may be formed in the process chamber (110). The process chamber (110) may be connected to a vacuum pump (not shown) through an exhaust pipe (114) to create a vacuum atmosphere. Fur