Method of processing substrate

Abstract

A substrate processing method according to one aspect of the present invention is a substrate processing method using a substrate processing apparatus comprising: a process chamber having a reaction space formed therein for processing a substrate having a composite film pattern formed therein in which at least a plurality of first insulating layers and a plurality of second insulating layers are alternately stacked on the lower layer; 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 pretreatment step of forming a passivation layer by supplying a pretreatment gas containing a hydrogen-containing gas and an oxygen-containing gas onto the substrate through the gas injection member; and a step of supplying an etchant containing a halogen-containing gas, a hydrogen-containing gas, an oxygen-containing gas, and a reaction product containing halogen and hydrogen generated by the reaction of the halogen-containing gas and the hydrogen-containing gas onto the substrate through the gas injection member to selectively etch at least partially the plurality of second insulating layers laterally with respect to the plurality of first insulating layers.

Description

Technology Field

[0001] The present invention relates to semiconductor manufacturing, and more specifically, to a substrate processing apparatus and a substrate processing method. Background Technology

[0002] 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 inside the process chamber, and a process gas can be injected onto the substrate through a gas injection unit installed on the upper part of the substrate support.

[0003] Meanwhile, when one or more thin film patterns are formed on a substrate, multiple thin films may be exposed on the substrate. For example, insulating films such as 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 become thin, and there is a problem in that unwanted insulating films are etched due to a lack of selectivity during the etching step of these insulating films.

[0004] In addition, as the thickness of the insulating film decreases, it becomes difficult for the etching solution to penetrate, which limits conventional wet etching. Although dry etching using halide-based etching gases is being studied, there is a problem that the etching selectivity is not high. Furthermore, when a semiconductor layer is located beneath the insulating film, the semiconductor layer is also etched during the etching of the insulating film. The problem to be solved

[0005] The present invention aims to solve various problems, including those mentioned above, by providing a substrate processing method using dry etching with a high etching selectivity ratio during the manufacturing of highly integrated semiconductor devices. However, these problems are exemplary and do not limit the scope of the present invention. means of solving the problem

[0006] A substrate processing method according to one aspect of the present invention for solving the above problem comprises: a process chamber having a reaction space formed therein for processing a substrate having a composite film pattern formed therein in which a lower layer and at least a plurality of first insulating layers and a plurality of second insulating layers are alternately stacked on the lower layer; 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, wherein the method comprises: a pretreatment step of forming a passivation layer by supplying a pretreatment gas containing a hydrogen-containing gas and an oxygen-containing gas onto the substrate through the gas injection member; and a step of selectively etching at least partially in a lateral direction the plurality of second insulating layers with respect to the plurality of first insulating layers by supplying an etchant comprising a halogen-containing gas, a hydrogen-containing gas, an oxygen-containing gas, and a reaction product containing halogen and hydrogen generated by the reaction of the halogen-containing gas and the hydrogen-containing gas onto the substrate through the gas injection member, wherein in the etching step, the halogen At least one of the contained gas and the hydrogen-containing gas is activated in the plasma reactor and supplied to the gas injection unit in the form of radicals.

[0007] In the above substrate processing method, in the etching step, the halogen-containing gas and the inert gas may be supplied to the plasma reactor, and the hydrogen-containing gas and the oxygen-containing gas may be supplied to the gas injection unit.

[0008] In the above substrate processing method, in the etching step, the halogen-containing gas and inert gas may be supplied to the plasma reactor, and the hydrogen-containing gas and the oxygen-containing gas may also be supplied.

[0009] In the above substrate processing method, in the etching step, the hydrogen-containing gas and the oxygen-containing gas may be supplied to the plasma reactor, and the halogen-containing gas may be supplied to the gas injection unit.

[0010] In the above substrate processing method, after the etching step, the step of removing the passivation layer may be included.

[0011] In the above substrate processing method, the passivation layer is formed on at least an exposed portion of the underlying layer, and in the etching step, the plurality of second insulating layers can be selectively etched with respect to the plurality of first insulating layers and the underlying layer.

[0012] In the above substrate processing method, the plurality of first insulating layers include a silicon oxide film, the plurality of second insulating layers include a silicon nitride film, and the underlayer may include a polysilicon layer.

[0013] In the above substrate processing method, in the etching step, the halogen-containing gas is activated in the plasma reactor and supplied to the gas injection unit in the form of radicals, and the hydrogen-containing gas and the oxygen-containing gas can be supplied to the gas injection unit in an inert state.

[0014] In the above substrate processing method, the hydrogen-containing gas and the oxygen-containing gas can be supplied to the gas injection unit through a connecting pipe connecting the plasma reactor and the gas injection unit.

[0015] In the above substrate processing method, the halogen-containing gas may include NF3 gas, the hydrogen-containing gas may include NH3 gas, and the reactant may include ammonium fluoride (NH3(HF)x).

[0016] In the above substrate processing method, the oxygen-containing gas may include O2 gas, O3 gas, or N2O gas. Effects of the invention

[0017] According to the substrate processing method according to some embodiments of the present invention as described above, a high etching selectivity can be achieved in the insulating film etching process during the manufacture of a highly integrated device. Of course, the scope of the present invention is not limited by this effect. Brief explanation of the drawing

[0018] FIG. 1 is a schematic diagram showing a substrate processing apparatus according to one embodiment of the present invention. FIG. 2 is a flowchart showing a substrate processing method according to one embodiment of the present invention. FIGS. 3 and 4 are schematic cross-sectional views of a substrate showing a substrate processing method according to one embodiment of the present invention. FIGS. 5 to 8 are schematic cross-sectional views of a substrate showing a substrate processing method according to another embodiment of the present invention. Figure 9 is an RGA analysis result showing the components of the etchant in the etching step in a substrate processing method according to some embodiments of the present invention. FIG. 10 is a graph showing the etching selectivity of insulating films according to the temperature of the substrate processing unit in a substrate processing method according to some embodiments of the present invention. FIG. 11 is a graph showing the amount of etching of each layer depending on whether pretreatment is performed in a substrate processing method according to some embodiments of the present invention. Specific details for implementing the invention

[0019] Hereinafter, several preferred embodiments of the present invention will be described in detail with reference to the attached drawings.

[0020] 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.

[0021] FIG. 1 is a schematic diagram showing a substrate processing apparatus (100) according to one embodiment of the present invention.

[0022] 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).

[0023] 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. Furthermore, the process chamber (110) may include an inlet / outlet for loading the substrate (S) into or unloading it from the reaction space (112), and a gate structure (not shown) for opening and closing the inlet / outlet. The process chamber (110) may be provided in various shapes and may include, for example, a side wall portion defining the reaction space (112) and a cover portion located on the top of the side wall portion, such as a top lead.

[0024] A gas injection unit (120) may be coupled to the process chamber (110) to supply process gas supplied from outside the process chamber (110) to the reaction space (112). More specifically, the gas injection unit (120) may be coupled to the process chamber (110) so as to face the substrate support (130). For example, the gas injection unit (120) may be installed on the upper part of the process chamber (110) to inject process gas onto a substrate (S) placed on the substrate support (130).

[0025] In some embodiments, the gas injection unit (120) may include an inlet (122) into which process gas is introduced through a gas pipe (152), and a distribution plate (124) for injecting the process gas introduced through the inlet (122) and dispersed internally into a reaction space (112). Furthermore, the gas injection unit (120) may further include a blocker plate for dispersing the process gas that has passed through the inlet (122).

[0026] In some embodiments, the gas injection unit (120) may have various forms, such as a shower head or a nozzle. If the gas injection unit (120) is in the form of a shower head, the gas injection unit (120) may be coupled to the process chamber (110) in a manner that partially covers the upper part of the process chamber (110). For example, the gas injection unit (120) may be coupled to the cover or top lid of the process chamber (110).

[0027] A substrate support member (130) may be coupled to a process chamber (110) to support a substrate (S) within a processing space (112). For example, the substrate support member (130) may be installed in the process chamber (110) opposite to a gas injection member (120). Furthermore, the substrate support member (130) may be equipped with a heater (182) for heating the substrate (S). For example, the heater (182) may be provided within the substrate support member (130). A heater power supply member (180) is connected to the heater (182) to supply power to the heater (182), and additionally, an AC filter (185) may be interposed between the heater (182) and the heater power supply member (180).

[0028] The top plate shape of the substrate support (130) generally corresponds to the shape of the substrate (S), but is not limited thereto and can be provided in various shapes larger than the substrate (S) so as to stably seat the substrate (S). In one example, the shaft of the substrate support (130) may be connected to an external motor (not shown) to enable vertical movement, and in this case, a bellows tube (not shown) may be connected to maintain airtightness. Furthermore, since the substrate support (130) is configured to seat the substrate (S) thereon, it may be referred to as a substrate seating part, a susceptor, etc.

[0029] In some embodiments, the substrate support (130) may further include an electrostatic electrode to apply electrostatic force to the substrate (S) and fix it thereon. In this case, the electrostatic electrode may receive DC power from an electrostatic power supply (not shown).

[0030] A plasma reactor (150) may be placed outside the process chamber (110) to be connected to a gas injection unit (120). The plasma reactor (150) may be connected to the gas injection unit (120) through a connecting pipe (152). Furthermore, process gas may be introduced into the plasma reactor (150) through a gas pipe (154). The plasma reactor (150) may also be called a remote plasma reactor or a remote plasma generator in that it is placed outside the process chamber (110).

[0031] Furthermore, a plasma power supply unit (140) for applying power may be connected to the plasma reactor (150). For example, the plasma power supply unit (140) may include at least one RF power source to apply at least one RF (radio frequency) power to the process chamber (110). The plasma reactor (150) can form a plasma atmosphere using an inductive coupled plasma (ICP) method, a capacitive coupled plasma (CCP) method, a toroidal plasma method, a microwave (MW) method, etc.

[0032] A plasma reactor (150) can receive at least one process gas through a gas pipe (154) and apply plasma power to form a plasma atmosphere inside, thereby activating the process gas to generate radicals. These radicals are supplied to a gas injection unit (120) through a connecting pipe (152) and can be injected onto a substrate (S) through the gas injection unit (120). Optionally, the connecting pipe (152) may be heated to prevent the generation or adsorption of byproducts. For example, a heater jacket or heating tape may be wrapped around the connecting pipe (152).

[0033] In some embodiments, the gas injection unit (120) may receive additional process gas through a separate gas pipe (153) connected to a connecting pipe (152) without passing through the plasma reactor (150). The process gas supplied through the gas pipe (153) and the process gas or radicals supplied through the plasma reactor (150) may be mixed or react with each other in the connecting pipe (152).

[0034] In some embodiments, the gas injection unit (120) may be provided with a heating means, such as a heater (128). Accordingly, the temperature of the gas injection unit (120) may be controlled by the heater (128). The heater (128) may include various types of heating means, such as a cartridge heater, a heating wire heater, a heat exchanger, an infrared heater, a laser heater, etc.

[0035] In some embodiments, the substrate processing device (100) may be used as an etching device or a pretreatment device for etching a thin film of a substrate (S). Hereinafter, a substrate processing method according to embodiments of the present invention will be described with reference to the substrate processing device (100).

[0036] FIG. 2 is a flowchart showing a substrate processing method according to one embodiment of the present invention, and FIG. 3 to 4 are schematic cross-sectional views of a substrate showing a substrate processing method according to one embodiment of the present invention.

[0037] Referring to FIG. 3, a composite film pattern (56) may be formed on a substrate (S). For example, the substrate (S) may include a semiconductor wafer (52), and a structure for forming a semiconductor device on the semiconductor wafer (52) may be formed. More specifically, a composite film pattern (56) may be formed on the semiconductor wafer (52). The semiconductor wafer (52) may include a single crystal structure of a semiconductor material, such as silicon, germanium, silicon-germanium, etc., and may further include a semiconductor epitaxial layer, etc.

[0038] The composite film pattern (56) may include a pattern structure in which a plurality of first insulating layers (54) and a plurality of second insulating layers (55) are alternately stacked. After the first insulating layers (54) and the second insulating layers (55) are alternately stacked, the pattern may be patterned to form a plurality of trenches (57) using photolithography and etching techniques. For example, the first insulating layers (54) may include a silicon oxide film, and the second insulating layers (55) may include a silicon nitride film.

[0039] In some embodiments, the substrate (S) may be processed using a substrate processing device (100). For example, the substrate (S) may be processed while seated on a substrate support (130) within a process chamber (110). More specifically, a step of introducing the substrate (S) into the process chamber (110) and seating it on the substrate support (130) may be performed.

[0040] Referring to FIGS. 1 to 4, according to one embodiment of the substrate processing method, the method may include a step (S20) of supplying an etchant onto a substrate (S) through a gas injection unit (120) to selectively etch at least partially the second insulating layers (55) laterally with respect to the first insulating layers (54).

[0041] For example, in the etching step (S20), the etchant may include a halogen-containing gas, a hydrogen-containing gas, an oxygen-containing gas, and a reactant containing halogen and hydrogen produced by the reaction of the halogen-containing gas and the hydrogen-containing gas. The reactant in the etchant may be produced by the reaction of the halogen-containing gas and the hydrogen-containing gas inside the connecting pipe (152), inside the gas injection unit (120), or in the reaction space (112) inside the process chamber (110).

[0042] In some embodiments, an inert gas may be supplied to the plasma reactor (150) to perform a plasma ignition process within the plasma reactor (150).

[0043] In some embodiments, during the etching step (S20), at least one of the halogen-containing gas and the hydrogen-containing gas may be activated in a plasma reactor (150) and supplied to a gas injection unit (120) in the form of radicals.

[0044] For example, in the etching step (S20), a halogen-containing gas and an inert gas may be supplied to the plasma reactor (150), and a hydrogen-containing gas and an oxygen-containing gas may be supplied to the gas injection unit (120). Accordingly, the halogen-containing gas is activated in the plasma reactor (150) and supplied to the gas injection unit (120) in the form of radicals, and the hydrogen-containing gas and the oxygen-containing gas may be supplied to the gas injection unit (120) in an inactive state through the gas pipe (153) without passing through the plasma reactor (150).

[0045] More specifically, a halogen-containing gas is activated in a plasma reactor (150) and supplied in the form of radicals to a gas injection unit (120) through a connecting pipe (152), and hydrogen-containing gas and oxygen-containing gas can be supplied to the connecting pipe (152) through a gas pipe (153). Furthermore, the radicals of the halogen-containing gas and the hydrogen-containing gas may react with each other in the connecting pipe (152) or the gas injection unit (120) to produce a reaction product containing halogen and hydrogen.

[0046] As another example, a hydrogen-containing gas may be activated in a plasma reactor (150) and supplied to a gas injection unit (120) in the form of radicals, and a halogen-containing gas and an oxygen-containing gas may be supplied to the gas injection unit (120) in an inactive state through a gas pipe (153) without passing through the plasma reactor (150). More specifically, a hydrogen-containing gas may be activated in a plasma reactor (150) and supplied to a gas injection unit (120) in the form of radicals through a connecting pipe (152), and a halogen-containing gas and an oxygen-containing gas may be supplied to the connecting pipe (152) through a gas pipe (153). Furthermore, the radicals of the hydrogen-containing gas and the halogen-containing gas may react with each other in the connecting pipe (152) or the gas injection unit (120) to produce a reaction product containing halogen and hydrogen.

[0047] As another example, in the etching step (S20), two or more or all of the hydrogen-containing gas, halogen-containing gas, and oxygen-containing gas may be supplied to the gas injection unit (120) through the plasma reactor (150). In this case, at least one or all of these gases may be activated and discharged from the plasma reactor (150) in the form of radicals. For example, the halogen-containing gas and inert gas may be supplied to the plasma reactor (150), and the hydrogen-containing gas and oxygen-containing gas may also be supplied to the plasma reactor (150).

[0048] In this case, radicals of the hydrogen-containing gas and radicals of the halogen-containing gas may react with each other in the connecting pipe (152) or the gas injection part (120) to produce a reaction product containing halogen and hydrogen. However, if both the hydrogen-containing gas and the halogen-containing gas are activated in the plasma reactor (150), there is a risk that by-products may be adsorbed in the plasma reactor (150) as the radicals of these gases react within the plasma reactor (150) to produce a reaction product.

[0049] Therefore, by activating only one of the hydrogen-containing gas and halogen-containing gas through the plasma reactor (150) and supplying the remaining gases in an inactive form to the connecting pipe (152) or gas injection unit (120), the contamination of the plasma reactor (150) can be reduced.

[0050] As another example, in the etching step (S20), hydrogen-containing gas and oxygen-containing gas may be supplied to the plasma reactor (150), and halogen-containing gas may be supplied to the gas injection unit (120). In this case, the hydrogen-containing gas and oxygen-containing gas may be activated in the plasma reactor (150) and supplied to the gas injection unit (120) in the form of radicals.

[0051] In some embodiments, the halogen-containing gas may include a fluorine-based or chlorine-based gas, and the hydrogen-containing gas may include a gas containing both hydrogen and nitrogen. In a more specific example, the halogen-containing gas may include NF3 gas, the hydrogen-containing gas may include NH3 gas, and the inert gas may include argon (Ar) gas.

[0052] NF3 gas and NH3 gas can react with each other in a state where at least one of the two gases is activated to produce an ammonium fluoride (NH3(HF)x) reaction product. This ammonium fluoride can be used as an etchant to primarily etch the second insulating layers (55). When NF3 gas, NH3 gas, and Ar gas are supplied to the gas injection unit (120) and at least one of NF3 gas and NH3 gas is activated, as shown in FIG. 9, it can be seen through RGA analysis that NH3(HF)3 is generated in the reaction space (112) within the process chamber (110) in addition to Ar, NH3, and HF gases.

[0053] Furthermore, the oxygen-containing gas may include O2 gas, O3 gas, or N2O gas. The oxygen-containing gas can help to uniformly etch the silicon nitride film in the top portion and bottom portion when etching the second insulating layers (55), such as the silicon nitride film, in a composite film pattern (56) composed of a stack of silicon oxide film and a silicon nitride film.

[0054] For example, by adding an oxygen-containing gas with relatively high electronegativity, such as O2 gas, to ammonium fluoride to add oxygen bonds to relatively weak hydrogen bonds, the ionization efficiency of fluoride is reduced, thereby reducing the surface modification efficiency by fluoride and helping the ammonium fluoride reach the bottom of the composite film pattern (56) without thermal decomposition. Accordingly, the uniformity in the vertical direction can be increased when etching the silicon nitride film in the composite film pattern (56).

[0055] When etching the composite film pattern (56), the etching selectivity may depend on the temperature of the substrate (S), that is, the temperature of the substrate support (130). Referring to FIG. 10, it can be seen that the etching amount and etching selectivity of the silicon nitride film (SiN) and the silicon oxide film (SiO2) vary depending on the temperature of the heater (182) within the substrate support (130). In order to selectively etch the silicon nitride film (SiN) relative to the silicon oxide film (SiO2), the temperature of the heater (182) or the substrate support (130) is 100 o It can be C or higher, and to obtain high etch selectivity, 110 o It can be maintained at C or higher.

[0056] However, these results are for the etching of silicon nitride (SiN) and silicon oxide (SiO2) films deposited by the atomic layer deposition (ALD) method, and the temperature range for the etching selectivity of silicon nitride (SiN) and silicon oxide (SiO2) films formed by other methods and conditions, such as plasma-enhanced chemical vapor deposition (PECVD), may differ.

[0057] FIGS. 5 to 8 are schematic cross-sectional views of a substrate showing a substrate processing method according to another embodiment of the present invention. The substrate processing method according to this embodiment may refer to the substrate processing method of FIGS. 3 to 4, and a description redundant in the two embodiments is omitted.

[0058] Referring to FIGS. 1, 2 and FIGS. 5 through 8, the substrate processing method may include a pretreatment step (S10) of supplying a pretreatment gas onto a substrate (S) through a gas injection unit (120) to form a passivation layer (58) on the substrate (S), and a step (S20) of supplying an etchant onto a substrate (S) through a gas injection unit (120) to selectively etch at least partially the second insulating layers (55) on the first insulating layers (54) laterally. Optionally, the substrate processing method may further include a step (S30) of removing the passivation layer (58) after the etching step (S20).

[0059] Referring to FIGS. 1, 2 and 5, a composite film pattern (56) may be formed on a lower layer (53). For example, the lower layer (53) may be formed on a semiconductor wafer (52), and the composite film pattern (56) may be formed on the lower layer (53). In some embodiments, the lower layer (53) may include a polysilicon layer.

[0060] Referring to FIGS. 1, 2 and 6, a passivation layer (58) may be formed on a substrate (S) in a pretreatment step (S10). For example, the passivation layer (58) may be formed on a portion exposed by the composite film pattern (56) of at least the lower layer (58). Furthermore, the passivation layer (58) may be formed on the sidewalls of the first insulating layers (54) and the second insulating layers (55) exposed by the trenches (57), the upper surface of the lower layer (53), and the upper surface of the composite film pattern (56).

[0061] More specifically, in the pretreatment step (S10), a pretreatment gas containing a hydrogen-containing gas and an oxygen-containing gas can be supplied onto the substrate (S). In the pretreatment step (S10), the oxygen-containing gas among the pretreatment gases can oxidize the exposed portion of the substrate (S). The passivation layer (58) can be formed with different thin films and different thicknesses on the lower layer (53) and the composite film pattern (56).

[0062] For example, the passivation layer (58) may be formed as a silicon oxide film on the underlying layer (53), but may not be separated as a separate film on the first insulating layers (54) and the second insulating layers (55). That is, notwithstanding FIG. 6, the passivation layer (58) on the composite film pattern (56) composed of a stack of silicon oxide and silicon nitride films may not be separated as a separate layer but may become a surface treatment layer.

[0063] In some embodiments, the pretreatment step (S10) may be called an oxygen-treatment (O2-treatment) step, and the hydrogen-containing gas in the pretreatment gas may be omitted.

[0064] In some embodiments, the hydrogen-containing gas and the oxygen-containing gas in the pretreatment step (S10) may be supplied to the gas injection unit (120) in an inactive state. For example, in the pretreatment step (S10), the hydrogen-containing gas and the oxygen-containing gas may be supplied to the connecting pipe (152) through the gas pipe (153).

[0065] In some embodiments, during the pretreatment step (S10), the halogen-containing gas may be supplied to the gas injection unit (120) in an inert state through the plasma reactor (150) or the supply may be blocked. Since the halogen-containing gas is not substantially needed during the pretreatment step (S10), its supply may be blocked or it may be supplied in an inert state so as not to participate in the reaction. As another example, the halogen-containing gas may be supplied in an inert state to the connecting pipe (152) through the gas pipe (153).

[0066] Referring to FIGS. 1, 2 and 7, in the etching step (S20), an etchant comprising a halogen-containing gas, a hydrogen-containing gas, an oxygen-containing gas, and a reactant containing halogen and hydrogen is supplied onto a substrate (S) through a gas injection unit (120) so that the second insulating layers (55) can be selectively etched at least partially laterally with respect to the first insulating layers (54).

[0067] For the etching step (S20) of this embodiment, you can refer to the description of the etching step (S20) in the embodiment of FIG. 3 and FIG. 4.

[0068] The passivation layer (58) can reduce or prevent the etching of the underlying layer (53) during the etching step (S20). Furthermore, by adding an oxygen-containing gas in addition to ammonium fluoride as an etchant during the etching step (S20), the passivation layer (58) can be continuously formed on the underlying layer (53). Accordingly, even if the passivation layer (58) on the underlying layer (53) is partially etched during the etching step (S20), it can be continuously replenished, thereby preventing the etching of the underlying layer (53).

[0069] Furthermore, since the passivation layer (58) on the second insulating layers (54) is substantially nothing more than a surface treatment layer rather than a separate layer, the passivation layer (58) on the second insulating layers (54) can be etched without being distinguished from the second insulating layers (54) during the etching step (S20).

[0070] As described above, by supplying a halogen-containing gas, a hydrogen-containing gas, and an oxygen-containing gas together in the etching step (S20), a reactant containing halogen and hydrogen is produced and used as an etchant, thereby allowing the second insulating layers (55) in the composite film pattern (56) to be selectively etched with respect to the underlayer (53) and the second insulating layers (54). In the etching step (S20), the oxygen-containing gas not only serves to prevent the etching of the underlayer (53) by oxidizing the underlayer (53), but also contributes to increasing the etching uniformity at the bottom and top portions of the second insulating layers (55) in the composite film pattern (56).

[0071] In some embodiments, the aforementioned pretreatment step (S10) may be omitted, and an etching step (S20) may be performed. In this case, oxidation of the underlayer (53) by oxygen gas during the etching step (S20) may partially prevent the etching of the underlayer (53). However, since etching and oxidation may be performed simultaneously, it may be difficult to exclude the underlayer (53) from being partially etched.

[0072] In some embodiments, the etching step (S20) may be performed in two or more temporally separated steps. For example, the etching step (S20) may be partially performed after the pretreatment step (S10), and then the etching step (S20) may follow in earnest.

[0073] Referring to FIGS. 1, 2 and 8, a step (S30) of removing the passivation layer (58) can be performed after the etching step (S20). For example, the passivation layer (58), such as a silicon oxide film, can be removed by performing an annealing treatment while supplying an oxide etching gas onto the substrate (S). For example, the oxide etching gas may include halide radicals or NH4F reactants, and further may include H2 gas and O3 gas. In such an atmosphere, surface cleaning can be performed while removing the surface oxide.

[0074] FIG. 12 is a graph showing the etching amount of each layer depending on whether pretreatment is performed in a substrate processing method according to some embodiments of the present invention.

[0075] Referring to FIG. 12, when pretreatment is omitted, the silicon nitride film (SiN) is etched and the polysilicon layer is partially etched into the underlying layer (53). However, when oxygen treatment (O2-treatment) is added as pretreatment, the underlying layer (53) and the silicon oxide film (SiO2) are hardly etched, and the silicon nitride film (SiN) is etched with a high selectivity.

[0076] Accordingly, according to the substrate processing apparatus (100) and substrate processing method according to the embodiments of the present invention, the second insulating layers (55) can be uniformly etched with a relatively high selectivity ratio with respect to the first insulating layers (54) in the composite film pattern (56), and furthermore, the etching of the underlying layer (53) can be reduced or prevented.

[0077] The present invention has been described with reference to the embodiments illustrated in the drawings, but this is merely illustrative, and those skilled in the art will understand that various modifications and equivalent alternative embodiments are possible therefrom. Accordingly, the true technical scope of protection of the present invention should be determined by the technical spirit of the appended claims. Explanation of the symbols

[0078] 100: Substrate processing device 110: Process chamber 120: Gas injection unit 130: Substrate support 140: Plasma power supply 150: Plasma reactor

Claims

Claim 1 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 composite film pattern formed therein, wherein a lower layer and at least a plurality of first insulating layers and a plurality of second insulating layers are alternately stacked on the lower layer; 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 pretreatment step of forming a passivation layer by supplying a pretreatment gas containing a hydrogen-containing gas and an oxygen-containing gas onto the substrate through the gas injection member; and supplying an etchant comprising a halogen-containing gas, a hydrogen-containing gas, an oxygen-containing gas, and a reactant containing halogen and hydrogen generated by the reaction of the halogen-containing gas and the hydrogen-containing gas onto the substrate through the gas injection unit, thereby selectively etching at least partially the plurality of second insulating layers laterally with respect to the plurality of first insulating layers, wherein in the etching step, at least one of the halogen-containing gas and the hydrogen-containing gas is activated in the plasma reactor and supplied to the gas injection unit in the form of a radical, wherein the plurality of first insulating layers comprise a silicon oxide film, and the plurality of second insulating layers comprise a silicon nitride film, and wherein in the etching step, the temperature of the substrate support is 100 so that the plurality of second insulating layers are selectively etched with respect to the plurality of first insulating layers. o A substrate processing method maintained at C or higher. Claim 2 A substrate processing method according to claim 1, wherein, in the etching step, the halogen-containing gas and the inert gas are supplied to the plasma reactor, and the hydrogen-containing gas and the oxygen-containing gas are supplied to the gas injection unit. Claim 3 A substrate processing method according to claim 1, wherein in the etching step, the halogen-containing gas and the inert gas are supplied to the plasma reactor, and the hydrogen-containing gas and the oxygen-containing gas are also supplied to the plasma reactor. Claim 4 A substrate processing method according to claim 1, wherein, in the etching step, the hydrogen-containing gas and the oxygen-containing gas are supplied to the plasma reactor, and the halogen-containing gas is supplied to the gas injection unit. Claim 5 A substrate processing method according to claim 1, comprising the step of removing the passivation layer after the etching step. Claim 6 A substrate processing method according to claim 1, wherein the passivation layer is formed on at least an exposed portion of the underlying layer, and in the etching step, the plurality of second insulating layers are selectively etched with respect to the plurality of first insulating layers and the underlying layer. Claim 7 A substrate processing method according to claim 6, wherein the lower layer comprises a polysilicon layer, and after the etching step, the step of removing the passivation layer. Claim 8 A substrate processing method according to claim 1, wherein, in the etching step, the halogen-containing gas is activated in the plasma reactor and supplied to the gas injection unit in the form of radicals, and the hydrogen-containing gas and the oxygen-containing gas are supplied to the gas injection unit in an inert state. Claim 9 A substrate processing method according to claim 8, wherein the hydrogen-containing gas and the oxygen-containing gas are supplied to the gas injection unit through a connecting pipe connecting the plasma reactor and the gas injection unit. Claim 10 A substrate treatment method according to claim 1, wherein the halogen-containing gas comprises NF3 gas, the hydrogen-containing gas comprises NH3 gas, and the reactant comprises ammonium fluoride (NH3(HF)x). Claim 11 A substrate treatment method according to claim 1, wherein the oxygen-containing gas comprises O2 gas, O3 gas, or N2O gas.

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