Method for forming silicon-contained thin film comprising stress relief layer and substrate processing apparatus therefor

Abstract

The present invention relates to a method for forming a silicon-containing thin film including a stress relief layer, and more specifically, to a method for forming a silicon-containing thin film capable of improving the physical properties of the thin film by forming a stress relief layer through a third process gas treatment using plasma between bulk thin films. A method for forming a silicon-containing thin film according to an embodiment comprises: a mounting step of mounting a substrate in a reaction space of a chamber; a first thin film layer forming step of forming a first silicon thin film layer on the substrate by supplying a first process gas and a second process gas containing a silicon-containing gas to the reaction space, respectively; an interlayer treatment step of forming a stress relief layer on the first thin film layer by supplying a third process gas to the reaction space and forming a plasma to treat the surface of the first thin film layer; and a second thin film layer forming step of forming a second silicon thin film layer on the stress relief layer by supplying the first process gas and the second process gas to the reaction space, respectively.

Description

Technology Field

[0001] The present invention relates to a method for forming a silicon-containing thin film including a stress relief layer and a substrate processing apparatus for the same. More specifically, the invention relates to a method for forming a silicon-containing thin film capable of improving the physical properties of the thin film by forming a stress relief layer between bulk thin film layers through plasma treatment using a reaction gas during the deposition of a bulk thin film. Background Technology

[0002] Generally, semiconductor devices require a back-end-of-line (BEOL) process to form metal wiring and input / output terminals for interconnection on a transistor, a passivation layer to be deposited on top, and an etching process to connect with the metal wiring of the device.

[0003] A silicon thin film, including silicon oxide, which is formed as a protective film in an etching process, must have excellent etch selectivity and is required to be porous so as to exhibit a wet etching rate of approximately 120 to 130 Å / min.

[0004] In addition, silicon thin films require a low refractive index (RI, 1.46X) to match the optical properties of the photolithography process. Typically, silicon thin films exhibit a lower refractive index (RI) and a denser wet etching rate (WER) in etching solutions such as DHF as the number of silicon bonds (-Si) decreases. This results in a trade-off between RI and WER, creating process limitations in forming thin films with low RI and high WER.

[0005] In particular, silane-based silicon thin films formed via the plasma-enhanced chemical vapor deposition (PE-CVD) process exhibit a characteristic where the refractive index (RI) and stress are inversely proportional. That is, stress tends to decrease as the RI increases, and stress tends to increase as the RI decreases. This is confirmed to be consistent with limited RI-stress results even with changes in process conditions such as gas, pressure, gap, and power. Accordingly, for silicon thin films to serve as a protective layer, it is difficult to form properties that possess both low RI and low stress, so research is needed on methods to compensate for this. The problem to be solved

[0006] According to one embodiment, the invention aims to provide technical content regarding a method for forming a silicon thin film that can form a silicon thin film having porous characteristics suitable for wet etching while maintaining a low refractive index (low RI) and low compressive stress characteristics so as to be used as a protective film. means of solving the problem

[0007] A method for forming a silicon thin film according to an embodiment may include: a mounting step of mounting a substrate in a reaction space of a chamber; a first thin film layer forming step of forming a first silicon thin film layer on the substrate by supplying a first process gas and a second process gas containing a silicon-containing gas to the reaction space, respectively; an interlayer treatment step of forming a stress relief layer on the first thin film layer by supplying a third process gas to the reaction space and forming a plasma to treat the surface of the first thin film layer; and a second thin film layer forming step of forming a second silicon thin film layer on the stress relief layer by supplying the first process gas and the second process gas to the reaction space, respectively.

[0008] According to one embodiment, the silicon-containing gas may include one or more selected from the group consisting of monosilane, polysilane, alkylsilane, and aminosilane, and the second process gas may each include at least one of nitrous oxide (N2O) gas, ammonia (NH3) gas, oxygen (O2) gas, nitrogen (N2) gas, and a carrier gas.

[0009] According to one embodiment, the third process gas may include at least one of nitrous oxide (N2O) gas, nitric oxide (NO) gas, nitrogen dioxide (NO2) gas, nitrogen (N2) gas and argon (Ar) gas.

[0010] According to one embodiment, the thickness ratio of the first thin film layer and the second thin film layer may be 0.01 : 1 to 1 : 0.01.

[0011] According to one embodiment, the first thin film layer and the second thin film layer may each be any one of a silicon oxide film (SiO2 membrane), a silicon nitride film (SiN membrane), and a silicon oxynitride film (SiON membrane).

[0012] A substrate processing device according to an embodiment comprises: a reaction chamber forming a reaction space for substrate processing; a gas injection unit installed in the reaction chamber and supplying a first process gas, a second process gas, and a third process gas containing a silicon-containing gas to the reaction space, respectively; a substrate support unit installed inside the reaction space facing the gas injection unit and having the substrate placed on its upper surface; a gas supply unit connected to the gas injection unit and supplying the first process gas, the second process gas, and the third process gas, respectively; and a power supply unit applying power to form a plasma in the reaction space. The apparatus includes a control unit that controls the operation of the gas injection unit, substrate support unit, gas supply unit, and power supply unit, wherein the control unit controls the operation of the gas supply unit and power supply unit to form a plasma by supplying the first process gas and the second process gas, respectively, to the reaction space to form a first silicon thin film layer on the substrate, and controls the operation of the gas supply unit and power supply unit to form a plasma by supplying the third process gas, respectively, to the reaction space to form a stress relief layer on the first silicon thin film layer, and controls the operation of the gas supply unit and power supply unit to form a plasma by supplying the first process gas and the second process gas, respectively, to the reaction space to form a second silicon thin film layer on the stress relief layer. Effects of the invention

[0013] The method for forming a silicon thin film according to the embodiment forms a stress relief layer through inter-treatment using a third process gas with plasma, and by forming a bulk-type silicon thin film with an arrangement of a first thin film layer / stress relief layer / second thin film layer, a silicon thin film having a lower refractive index and lower stress characteristics compared to a bulk-type thin film without inter-treatment can be formed.

[0014] In addition, the physical properties of the bulk-type silicon thin film can be controlled by changing the interlayer treatment position between the first thin film and the second thin film.

[0015] In addition, since it is not a treatment of the top surface of the bulk type silicon thin film, it does not cause a significant difference in wet etching characteristics. Brief explanation of the drawing

[0016] Figure 1 is a process diagram showing a method for forming a silicon-containing thin film according to an embodiment. FIGS. 2(a), (b), and (c) are conceptual diagrams showing examples of silicon-containing thin films formed on a substrate having an arrangement of a first thin film layer / stress relief layer / second thin film layer by forming a silicon-containing thin film according to the method of forming a silicon-containing thin film according to the embodiment, and (d) is a conceptual diagram showing examples of silicon-containing thin films formed on a substrate having an arrangement of a thin film layer / stress relief layer. FIG. 3 is a diagram showing the configuration of a substrate processing device according to an embodiment. Specific details for implementing the invention

[0017] Below, with reference to the attached drawings, embodiments of the present invention are described in detail so that those skilled in the art can easily implement the invention. However, since the description of the present invention is merely an example for structural or functional explanation, the scope of the present invention should not be interpreted as being limited by the embodiments described in the text. That is, since the embodiments are subject to various modifications and may take various forms, the scope of the present invention should be understood to include equivalents capable of realizing the technical concept. Furthermore, the objectives or effects presented in the present invention do not imply that a specific embodiment must include all of them or only such effects; therefore, the scope of the present invention should not be understood as being limited by them.

[0018] The meaning of the terms described in this invention should be understood as follows.

[0019] Terms such as "first" and "second" are intended to distinguish one component from another, and the scope of rights shall not be limited by these terms. For example, the first component may be named the second component, and similarly, the second component may be named the first component. When a component is referred to as being "connected" to another component, it should be understood that it may be directly connected to that other component, or that there may be other components in between. Conversely, when a component is referred to as being "directly connected" to another component, it should be understood that there are no other components in between. Meanwhile, other expressions describing the relationship between components, such as "between" and "exactly between," or "adjacent to" and "directly adjacent to," shall be interpreted in the same manner.

[0020] A singular expression should be understood to include a plural expression unless the context clearly indicates otherwise, and terms such as "include" or "have" are intended to specify the existence of the set-up features, numbers, steps, actions, components, parts, or combinations thereof, and should be understood not to preclude the existence or addition of one or more other features, numbers, steps, actions, components, parts, or combinations thereof.

[0021] Unless otherwise defined, all terms used herein have the same meaning as generally understood by those skilled in the art to which this invention pertains. Terms defined in commonly used dictionaries should be interpreted as having meanings consistent with the context of the relevant technology and should not be interpreted as having an ideal or overly formal meaning unless explicitly defined in this invention.

[0022] Figure 1 is a process diagram showing a method for forming a silicon-containing thin film according to an embodiment.

[0023] Referring to FIG. 1, a method for forming a silicon-containing thin film according to an embodiment includes a settling step (S100); a first thin film layer forming step (S200); an interlayer treatment step (S300); and a second thin film layer forming step (S400).

[0024] First, the placement step (S100) is a step of placing a substrate (10) in the reaction space of the chamber.

[0025] The above chamber may be equipped in various types of conventional substrate processing devices used to deposit thin films using plasma.

[0026] The above substrate (10) has a plate shape and may be warped by the self-weight of the substrate (10) itself, and may be intended to control compressive stress and tensile stress by forming a thin film.

[0027] Additionally, the substrate (10) may be made of glass, silicon, or polymer material that can be charged with static electricity. Specifically, the substrate (10) may be made of a material including crystalline silicon, silicon oxide, silicon oxynitride, silicon nitride, strained silicon, silicon germanium, tungsten, titanium nitride, doped or undoped polysilicon, doped or undoped silicon wafer, patterned or unpatterned wafer, SOI (silicon on insulator), carbon-doped silicon oxide, silicon nitride, doped silicon, germanium, gallium arsenide, glass, sapphire, low k dielectrics, or a mixture thereof. The substrate (10) may be a semiconductor substrate (10) on which a predetermined device is formed, or it may be a bare wafer.

[0028] The first thin film layer formation step (S200) is a step of forming a first thin film layer (20) on a substrate (10) by supplying a first process gas and a second process gas containing a silicon-containing gas to the reaction space, respectively, and forming a plasma.

[0029] In this step, the reaction time can be adjusted to form a first thin film layer (20) of a desired thickness. Additionally, the first thin film layer formation step can be performed one or more times to form a first thin film layer (20) of a desired thickness on the substrate (10).

[0030] The first process gas may include a silicon-containing gas containing various conventional silicon precursors used to form a silicon thin film.

[0031] Specifically, the silicon-containing gas may include one or more selected from the group consisting of silane, alkylsilane, and aminosilane.

[0032] More specifically, the silane comprises silicon and hydrogen atoms, such as monosilane (SiH4), disilane (Si2H6), trisilane (Si3H8), and tetrasilane (Si4H 10 ), isotetrasilane, neopentasilan (Si5H 12 ), cyclopentasilan (Si5H 10 ), hexasilane (C6H 14 ), cyclohexasilane (Si6H 12 ) or a mixture of these can be used.

[0033] The above alkylsilane may be trimethylsilane (3MS), tetramethylsilane (4MS), or a mixture thereof.

[0034] The above aminosilane may include diisopropylaminosilane (DIPAS), butylaminosilane (BAS), bistert-butylaminosilane (BTBAS), dimethylaminosilane (DMAS), bisdimethylaminosilane (BDMAS), trisdimethylaminosilane (TDMAS), diethylaminosilane (DEAS), bisdiethylaminosilane (BDEAS), dipropylaminosilane (DPAS), diisopropylaminosilane (DIPAS), or a mixture thereof.

[0035] In particular, the silicon-containing gas may use a silane gas including monosilane, polysilane, or a mixture thereof, but is not limited thereto. The silicon-containing gas may use monosilane.

[0036] Additionally, the second process gas may form any one of a silicon oxide film (SiO2 layer), a silicon nitride film (SiN), or a silicon oxynitride film (SiON) as the first thin film layer (20). The second process gas may include nitrous oxide (N2O) gas, oxygen (O2) gas, ammonia (NH3) gas, a carrier gas, or a mixture thereof.

[0037] Additionally, in this step, a carrier gas may be supplied together with the first process gas and the second process gas. The carrier gas may include at least one gas selected from helium (He), neon (Ne), argon (Ar), krypton (Kr), xenon (Xe), and radon (Rn). In particular, the carrier gas may include argon (Ar) gas.

[0038] In this step, RF power is applied to a substrate processing device to form plasma in the reaction space, and a first process gas and a second process gas are supplied to form the first thin film layer (20) on the substrate (10).

[0039] The above interlayer treatment step (S300) is a step of supplying a third process gas to a reaction space and forming a plasma to induce one or more reactions among dehydration, dehydrogenation, and nitrification to form a stress relief layer (30) on the first thin film layer (20).

[0040] In this step, the optical and stress properties of the thin film can be changed through the structural rearrangement of film bonding and the resulting change in bonding length via inter-treatment of the third process gas using plasma.

[0041] The above third process gas may be a mixed gas comprising nitrous oxide (N2O) gas, nitric oxide (NO) gas, nitrogen dioxide (NO2) gas, nitrogen (N2) gas, argon (Ar) gas, or a mixture thereof.

[0042] The above third process gas is a reactive gas that forms radicals by plasma, and the formed radicals react with surface atoms of the first thin film layer (20) to induce one or more reactions among dehydration, dehydrogenation, and nitrification, and accordingly, can rearrange the atoms of the first thin film layer (20) to form a stress relief layer (30).

[0043] Specifically, nitrous oxide (N2O) gas, nitric oxide (NO) gas, and nitrogen dioxide (NO2) gas each induce one of the reactions of dehydration and dehydrogenation to form a stress relief layer (30), and the stress relief layer (30) can relieve stress on the substrate (10) by shrinking the thin film and reducing the volume of the thin film.

[0044] That is, by inducing a surface oxidation reaction between the residual source gas and the third process gas, the silicon-silicon (Si-Si) bond is rearranged into silicon-oxygen (Si-O) bonds, and as the Si-O bond increases, the size of the bonding atoms decreases and the bond length decreases, thereby allowing a thin film with high compressive stress to have low compressive stress.

[0045] In particular, when the first thin film layer (20) is a silicon oxide film or a silicon oxynitride film, dehydration and dehydrogenation of the silicon thin film are induced, causing shrinkage of the thin film, and the resulting reduction in the volume of the thin film can relieve stress.

[0046] In addition, the nitrogen gas forms radicals by the plasma, and the formed radicals transfer kinetic energy through inelastic collisions with the surface of the thin film, causing surface densification and atomic rearrangement.

[0047] In particular, if the first thin film layer (20) is a silicon nitride film or a silicon oxynitride film, it can induce surface densification and atomic rearrangement to relieve stress.

[0048] In this step, the above-mentioned interlayer treatment can be performed for 1 to 120 seconds. If the interlayer treatment is less than 1 second, the atomic rearrangement is insufficient, making it difficult to form a uniform stress relief layer (30), and if it exceeds 120 seconds, it is difficult to expect further improvement in physical properties.

[0049] As a specific example, the third process gas may be oxygen gas, and the oxygen gas may generate radicals by plasma to induce one or more reactions among dehydration, dehydrogenation, and nitrification on the first thin film layer to form a stress relief layer.

[0050] In addition, this step may further include a gas stabilization step after forming the stress relief layer (30).

[0051] The above gas stabilization step can be performed to improve process stability by providing time to stabilize the gas during the formation of the first thin film layer and the second thin film layer. Specifically, the gas stabilization step can be performed by stopping the application of RF power and leaving the substrate (10) at a temperature of 70 to 150°C for 10 to 1,200 seconds in a state where the plasma is removed, and through such a gas stabilization step, a stress relief layer (30) with a stable structure is formed.

[0052] The second thin film layer formation step (S400) is a step of supplying a first process gas and a second process gas to the reaction space and forming a plasma to form a second thin film layer (40) on the stress relief layer (30).

[0053] The second process gas mentioned above may have the same composition as the first process gas.

[0054] In addition, in this step, after forming the second thin film layer (40) as described above, a purge step of supplying purge gas to the reaction space may be further included, and the gas inside the reaction space may be pumped out to the outside of the reaction space.

[0055] Meanwhile, FIG. 2(a), (b), and (c) are conceptual diagrams showing examples of silicon-containing thin films formed on a substrate (10) by forming a silicon-containing thin film according to the method of forming a silicon-containing thin film according to the embodiment, such that the first thin film layer / stress relief layer / second thin film layer arrangement is formed, and (d) is a conceptual diagram showing examples of silicon-containing thin films formed on a substrate (10) such that the thin film layer / stress relief layer arrangement is formed.

[0056] Referring to FIG. 2, the first thin film layer (20) and the second thin film layer (40) formed in the above manner can control the physical properties of the bulk type silicon thin film by changing the interlayer processing position that forms the stress buffer layer.

[0057] In particular, the thickness ratio of the first thin film layer (20) and the second thin film layer (40) may be 0.01 : 1 to 1 : 0.01.

[0058] Specifically, the thickness (THK1) of the first thin film layer (20) and the thickness (THK2) of the second thin film layer may be the same as shown in FIG. 2(a), and may be different as shown in FIG. 2(b) and FIG. 2(c). In the method for forming a silicon thin film according to the embodiment, the physical properties of the bulk type silicon thin film can be controlled by changing the interlayer treatment position. That is, the first thin film layer (20) and the second thin film layer (40), which have the same or different thicknesses, are formed respectively, and the physical properties of the silicon thin film can be controlled by performing interlayer treatment during this process.

[0059] Through the above method, a bulk type silicon thin film having an arrangement of a first thin film layer / stress relief layer / second thin film layer can further relieve stress as the stress relief layer (30) approaches the surface layer, as shown in FIG. 2(c). That is, as the thickness (THK2) of the second thin film layer (40) becomes thinner than the thickness (THK1) of the first thin film layer (20), the stress relief effect increases, and conversely, the stress relief effect decreases.

[0060] In addition, the method for forming a silicon thin film according to the embodiment does not form a stress relief layer (30) on the uppermost surface of the bulk-type silicon thin film as shown in FIG. 2(d), so it does not cause a significant difference in wet etching characteristics. That is, if a stress relief layer (30) is formed on the surface as shown in FIG. 2(d), the wet etching characteristics are degraded due to the difference in physical properties between the silicon thin film and the stress relief layer (30). However, the method for forming a silicon thin film according to the embodiment can control the characteristics of the entire thin film without causing a change in physical properties by using plasma to perform inter-treatment at an arbitrary location of the bulk-type silicon thin film, rather than treating the surface of the thin film with plasma as described above.

[0061] The above interlayer treatment can change the optical and stress properties of the thin film through structural rearrangement of film bonding and the resulting change in bonding length.

[0062] In particular, SiO X Dehydration and dehydrogenation of silicon thin films containing (OH) are induced, causing shrinkage of the thin film, and the resulting reduction in the thin film's volume can relieve stress.

[0063] When a bulk-type silicon thin film is formed with an arrangement of a first thin film layer / stress relaxation layer / second thin film layer as described above, a thin film having a lower refractive index and lower stress characteristics compared to a bulk-type thin film without inter-treatment can be formed.

[0064] Accordingly, the method for forming a silicon thin film according to the embodiment can extend the usage limits by improving the characteristics of a silicon oxide film, which generally has a trade-off relationship between refractive index (RI) and stress.

[0065] Additionally, the first thin film layer (20) and the second thin film layer (40) may each be any one of a silicon oxide film (SiO2 membrane), a silicon nitride film (SiN membrane), or a silicon oxynitride film (SiON membrane), and the first thin film layer (20) and the second thin film layer (40) may have the same composition.

[0066] The method for forming a silicon thin film according to the above embodiment forms a stress relief layer (30) through inter-treatment using a third process gas with plasma, and forms a bulk type silicon thin film on a substrate (10) in an arrangement of a first thin film layer / stress relief layer / second thin film layer, thereby forming a silicon thin film having a lower refractive index and lower stress characteristics compared to a bulk type thin film without inter-treatment.

[0067] In addition, the physical properties of the bulk-type silicon thin film can be controlled by changing the interlayer treatment position between the first thin film and the second thin film.

[0068] In addition, since it is not a treatment of the top surface of the bulk type silicon thin film, it does not cause a significant difference in wet etching characteristics.

[0069] Meanwhile, the method for forming a silicon thin film as described above can be performed using a substrate processing apparatus as follows.

[0070] Specifically, the substrate processing device (100) according to the embodiment has a structure including a reaction chamber (110), a gas injection unit (120), a substrate support unit (130), a gas supply unit (140), a power supply unit (150), and a control unit (160) (see FIG. 3).

[0071] The reaction chamber (110) can form a reaction space for substrate processing inside. The reaction chamber (110) can be implemented using a chamber of various conventional structures that forms a space for substrate processing, such as thin film deposition or etching on a substrate.

[0072] The above gas injection unit (120) may be installed in the reaction chamber (110) to supply a first process gas, a second process gas, and a third process gas, respectively, to the reaction space. The gases may be supplied by connecting to a gas supply unit (140) installed outside the reaction chamber (110).

[0073] The gas injection unit (120) may be installed above the reaction chamber (110) facing the substrate support (130) to inject process gas onto a substrate (S) placed on the substrate support (130). The gas injection unit (120) may include at least one inlet hole formed on the upper or side to receive gas from the outside, and a plurality of injection holes formed downward facing the substrate (S) to inject gas onto the substrate (S).

[0074] The above gas injection unit (120) may have various shapes, such as a shower head or a nozzle. In particular, 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 covers the upper part of the reaction chamber (110). For example, the gas injection unit (120) may be coupled to the side wall portion in the form of a cover for the reaction chamber (110).

[0075] A substrate support (130) is installed in a process chamber (110) opposite to a gas injection unit (120), and a substrate (S) can be placed on its upper surface.

[0076] The substrate support member (130) generally corresponds to the shape of the substrate (S), but is not limited thereto; it may be larger than the substrate (S) and have various shapes so as to stably seat the substrate (S). For example, the substrate support member (130) may be connected to an external motor (not shown) to enable raising and lowering, and in this case, it may have a structure in which a bellows tube (not shown) is connected to maintain airtightness.

[0077] Since the substrate support member (130) described above is configured to support a substrate (S) on its upper surface, it may be referred to as a substrate support member, a substrate support, a susceptor, etc. The substrate support member (130) may include a heater for heating the substrate (S) and may include a heater power supply unit for supplying power to the heater.

[0078] The above gas supply unit (140) is connected to the gas injection unit (120) and serves to supply a first process gas, a second process gas, and a third process gas, respectively, to the reaction space of the reaction chamber, and can be implemented as a plurality of gas storage tanks installed outside the process chamber (110).

[0079] Additionally, the gas supply unit (140) can supply a first process gas, a second process gas, and a third process gas to the reaction space, respectively, and may include at least one gas storage tank for this purpose.

[0080] The above gas supply unit (140) may have a structure in which a flow control valve is installed, and may control the amount of gas supplied by the control unit (160) to be described later.

[0081] The power supply unit (150) serves to supply power for forming plasma in the reaction space. It may include at least one RF power source to apply at least one RF (radio frequency) power to the reaction chamber (110). For example, the power supply unit (150) may be connected to apply RF power to the gas injection unit (120). In this case, in a configuration where at least one RF power source is applied to the gas injection unit (120) to form a plasma atmosphere inside the process chamber, the gas injection unit (120) may be understood as a plasma electrode.

[0082] The above control unit (160) controls the operation of the gas injection unit (120), the gas supply unit (140), and the power supply unit (150).

[0083] The control unit (160) can control the formation of a first silicon thin film layer on a substrate by supplying a first process gas containing silicon-containing gas to the reaction space and forming a plasma, and then supplying a third process gas to the reaction space and forming a plasma to induce one or more reactions among dehydration, dehydrogenation, and nitrification for a preset time to form a stress relief layer on the first thin film layer, and then supplying a second process gas containing silicon-containing gas to the reaction space and forming a plasma to form a second silicon thin film layer on the stress relief layer.

[0084] In addition, the control unit (160) may also control the substrate having the stress relief layer formed thereon to be left at a temperature of 70 to 150°C for 10 to 1,200 seconds to stabilize the gas after forming the stress relief layer.

[0085] The present invention will be explained in more detail below with reference to examples.

[0086] The presented embodiments are merely specific examples of the present invention and are not intended to limit the technical scope of the present invention.

[0087] <Example 1-1>

[0088] A silicon oxide film with a structure as shown in Table 1 below was formed on a substrate. First, the substrate was placed in a reaction space, and then a first process gas, monosilane (SiH4), a second process gas, oxygen (O2), and a carrier gas were each supplied to the reaction space, and a plasma was formed to form a first PEOX layer with a thickness (THK) of 5 kÅ on the substrate.

[0089] A third process gas containing nitrous oxide and nitrogen was supplied to the reaction space, and a plasma was formed to form a stress relief layer (N2O TRT) on the first PEOX layer.

[0090] Subsequently, a source gas containing monosilane was supplied to the reaction space and a plasma was formed to form a second PEOX layer with a thickness of 5 kÅ on the substrate, thereby forming a bulk silicon oxide film (SiO2 layer) with an array of a first thin film layer / stress relief layer / second thin film layer.

[0091]

[0092] <Example 1-2>

[0093] A silicon oxide film of the first thin film layer / stress relaxation layer / second thin film layer arrangement was formed in the same manner as in Example 1-1, except that a first PEOX layer with a thickness of 9.5 kÅ and a second PEOX layer with a thickness of 0.5 kÅ were formed.

[0094] <Examples 1-3>

[0095] A silicon oxide film of the first thin film layer / stress relaxation layer / second thin film layer arrangement was formed in the same manner as in Example 1-1, except that a first PEOX layer with a thickness of 9.8 kÅ and a second PEOX layer with a thickness of 0.2 kÅ were formed.

[0096] <Example 2-1>

[0097] After placing the substrate in the reaction space, a source gas containing monosilane (SiH4), oxygen (O2), and nitrogen (N2) was supplied to the reaction space, and a plasma was formed to form a first SiON layer with a thickness (THK) of 5 kÅ on the substrate.

[0098] Nitrous oxide (N2O) was supplied as a third process gas to the reaction space, a plasma was formed, and the reaction was carried out for 3 seconds to form a stress relief layer on the first SiON layer.

[0099] Subsequently, a source gas containing monosilane (SiH4), oxygen (O2), and nitrogen (N2) was supplied to the reaction space, and a plasma was formed to form a second SiON layer with a thickness (THK) of 5 kÅ on the substrate, thereby forming a silicon oxynitride film (SiON layer) with an array of first thin film layer / stress relaxation layer / second thin film layer.

[0100] <Example 2-2>

[0101] A silicon oxynitride film (SiON layer) of the first thin film layer / stress relief layer / second thin film layer array was formed in the same manner as in Example 2-1, except that ammonia (NH3) gas was supplied as the third process gas and reacted for 30 seconds.

[0102] <Example 2-3>

[0103] A silicon oxynitride (SiON) layer was formed in the same manner as in Example 2-1, except that argon (Ar) gas was supplied as the third process gas and reacted for 30 seconds.

[0104] <Example 2-4>

[0105] A silicon nitride film (SiON layer) of the first thin film layer / stress relief layer / second thin film layer array was formed in the same manner as in Example 2-1, except that the third process gas was supplied and reacted for 30 seconds.

[0106] <Example 2-5>

[0107] A silicon nitride film (SiON layer) of the first thin film layer / stress relaxation layer / second thin film layer array was formed in the same manner as in Example 2-1, except that only plasma was treated for 30 seconds without supplying the third process gas.

[0108] <Example 3-1>

[0109] After placing the substrate in the reaction space, a source gas containing monosilane (SiH4) and ammonia (NH3) was supplied to the reaction space, and a plasma was formed to form a first SiN layer with a thickness (THK) of 5 kÅ on the substrate.

[0110] Argon (Ar) gas was supplied as a third process gas to the reaction space, a plasma was formed, and the reaction was carried out for 30 seconds to form a stress relief layer on the first SiN layer.

[0111] Subsequently, a source gas containing monosilane (SiH4) and ammonia (NH3) was supplied back into the reaction space and a plasma was formed to form a second SiN layer with a thickness (THK) of 5 kÅ on the substrate, thereby forming a silicon nitride film (SiN layer) with an array of first thin film layer / stress relaxation layer / second thin film layer.

[0112] <Example 3-2>

[0113] A silicon nitride film (SiN layer) was formed in the same manner as in Example 3-1, except that ammonia (NH3) gas was supplied as the third process gas.

[0114] <Comparative Example 1-1>

[0115] After placing the substrate in the reaction space, a source gas containing SiH4 and O2 was supplied to the reaction space, and a plasma was formed to form a PEOX layer with a thickness of 10 kÅ on the substrate.

[0116] <Comparative Example 1-2>

[0117] A PEOX layer was formed in the same manner as in Comparative Example 1, and then a third process gas containing nitrous oxide and nitrogen was supplied to the reaction space and a plasma was formed to form a stress relief layer (N2O TRT) on the PEOX layer, thereby forming a silicon oxide film of a thin film layer / stress relief layer arrangement.

[0118] <Comparative Example 2>

[0119] After placing the substrate in the reaction space, a source gas containing monosilane (SiH4) and ammonia (NH3) was supplied to the reaction space, and a plasma was formed to form a SiN layer with a thickness (THK) of 10 kÅ on the substrate.

[0120] <Experimental Example>

[0121] (1) Evaluation of physical properties 1

[0122] The physical properties of substrates containing silicon oxide films prepared by the methods according to Examples 1-1 to 1-3 and Comparative Examples 1-1 and 1-2 were evaluated, and the results are shown in Table 1 above.

[0123] As shown in Table 1, it was confirmed that the stress (STR) of the substrate was relieved by inter-treatment with nitrous oxide gas using plasma, and no change in refractive index (RI) was observed.

[0124] On the other hand, in the case of Comparative Example 1-2, although the stress (STR) of the substrate was relieved, it was confirmed that the wet etching rate (WER) was significantly reduced, exhibiting undesirable physical properties.

[0125] In addition, by comparing Examples 1-1 to 1-3, it was confirmed that the closer the location of the stress relief layer is to the surface of the silicon oxide film, the more the stress tends to be relieved.

[0126] Through the above results, it was confirmed that stress in thin films can be controlled through densification and dehydrogenation, and also through changes in atomic arrangement and bond length.

[0127] (2) Physical property evaluation 2

[0128] The stress of the thin film-containing substrate prepared by the method according to Example 2 was measured, and the results are shown in Table 2 below.

[0129]

[0130] As shown in Table 2, it was confirmed that stress changes significantly due to plasma treatment and interlayer treatment of the third process gas using plasma, and that stress can be controlled depending on the type of third process gas and reaction time.

[0131] In particular, it was confirmed that stress control is possible even in silicon oxynitride films through interlayer treatment of a third process gas using plasma.

[0132] (3) Physical property evaluation 3

[0133] The composition of the thin films prepared by the methods according to Examples 3-1, 3-2 and Comparative Example 2 was analyzed by X-ray photoelectron spectroscopy (XPS), and the results are shown in Table 3 below.

[0134]

[0135] As shown in Table 3, it was confirmed that the oxygen content in the thin films of Example 3-1 and Example 3-2 was significantly reduced compared to the untreated Comparative Example 2, and it was confirmed that the oxygen content could be lowered by dehydrogenation even when argon and ammonia gases were used as the third process gas. In particular, it was confirmed that stress control is possible in silicon nitride films through interlayer treatment of the third process gas using plasma.

[0136] Through the results described above, it was confirmed that the application process range of silicon thin films can be expanded by improving the trade-off between refractive index and stress, which is a characteristic of general silane-based silicon oxide films, through a third process gas treatment (inter-treatment) using plasma between the first and second thin film layers.

[0137] Furthermore, it refers to interlayer treatment rather than surface treatment, and it was confirmed that the overall physical properties of the thin film can be controlled by adjusting the treatment location.

[0138] In addition, it was confirmed that the physical properties of the thin film can be improved without changing the wet etching characteristics through interlayer treatment.

[0139] As described above, the detailed description of the preferred embodiments of the present invention disclosed is provided to enable those skilled in the art to implement and practice the present invention. Although the present invention has been described with reference to preferred embodiments, those skilled in the art will understand that various modifications and changes can be made to the present invention without departing from the scope of the invention. For example, those skilled in the art may utilize each configuration described in the embodiments described above in combination with one another. Accordingly, the present invention is not intended to be limited to the embodiments shown herein, but to be given the broadest scope consistent with the principles and novel features disclosed herein.

[0140] The present invention may be embodied in other specific forms without departing from the spirit and essential features of the invention. Accordingly, the above detailed description should not be interpreted restrictively in all respects but should be considered exemplary. The scope of the invention shall be determined by a reasonable interpretation of the appended claims, and all modifications within the equivalent scope of the invention are included within the scope of the invention. The invention is not intended to be limited to the embodiments shown herein, but to be given the broadest possible scope consistent with the principles and novel features disclosed herein. Furthermore, embodiments may be constructed by combining claims that are not explicitly related in the claims, or by including them as new claims through amendments made after filing.

Claims

Claim 1 A method for forming a silicon-containing thin film, comprising: a mounting step of mounting a substrate in a reaction space of a chamber; a first thin film layer forming step of forming a first silicon thin film layer on the substrate by supplying a first process gas and a second process gas containing a silicon-containing gas to the reaction space, respectively; an interlayer treatment step of forming a stress relief layer on the first thin film layer by supplying a third process gas to the reaction space, forming a plasma, and treating the surface of the first thin film layer; and a second thin film layer forming step of forming a second silicon thin film layer on the stress relief layer by supplying the first process gas and the second process gas to the reaction space, respectively. Claim 2 A method for forming a silicon-containing thin film according to claim 1, wherein the silicon-containing gas comprises one or more selected from the group consisting of monosilane, polysilane, alkylsilane, and aminosilane. Claim 3 A thin film forming method according to claim 1, wherein the second process gas further comprises at least one of nitrous oxide (N2O) gas, ammonia (NH3) gas, oxygen (O2) gas, nitrogen (N2) gas and a carrier gas. Claim 4 A method for forming a thin film according to claim 1, wherein the third process gas comprises at least one of nitrous oxide (N2O) gas, nitric oxide (NO) gas, nitrogen dioxide (NO2) gas, nitrogen (N2) gas and argon (Ar) gas. Claim 5 A thin film forming method according to claim 1, characterized in that the interlayer treatment step is performed for 1 to 120 seconds. Claim 6 A method for forming a thin film according to claim 1, wherein the first thin film layer and the second thin film layer have a thickness ratio of 0.01 : 1 to 1 : 0.

01. Claim 7 A thin film forming method according to claim 1, wherein the interlayer treatment step further comprises a gas stabilization step for stabilizing the gas inside the reaction space after forming the stress relief layer. Claim 8 A method for forming a thin film according to claim 1, wherein the first thin film layer and the second thin film layer are each one of a silicon oxide film (SiO2 membrane), a silicon nitride film (SiN membrane), and a silicon oxynitride film (SiON membrane). Claim 9 A reaction chamber forming a reaction space for substrate processing; a gas injection unit installed in the reaction chamber and supplying a first process gas, a second process gas, and a third process gas containing silicon-containing gas to the reaction space, respectively; a substrate support unit installed inside the reaction space facing the gas injection unit and having the substrate placed on its upper surface; a gas supply unit connected to the gas injection unit and supplying the first process gas, the second process gas, and the third process gas, respectively; and a power supply unit applying power to form plasma in the reaction space. A substrate processing apparatus comprising a control unit that controls the operation of the gas injection unit, substrate support unit, gas supply unit, and power supply unit, wherein the control unit controls the operation of the gas supply unit and power supply unit to form a plasma by supplying the first process gas and the second process gas, respectively, to the reaction space to form a first silicon thin film layer on the substrate, and controls the operation of the gas supply unit and power supply unit to form a plasma by supplying the third process gas, respectively, to the reaction space to form a stress relief layer on the first silicon thin film layer, and controls the operation of the gas supply unit and power supply unit to form a plasma by supplying the first process gas and the second process gas, respectively, to the reaction space to form a second silicon thin film layer on the stress relief layer. Claim 10 A substrate processing apparatus according to claim 9, wherein the control unit controls to stabilize the gas inside the reaction space after forming the stress relief layer.

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