Film forming method and film forming apparatus

Abstract

To provide a technique for selectively forming a film on a top surface of a convex portion in a substrate surface including adjacent concave and convex portions.SOLUTION: The film forming method includes the following steps. A liquid is supplied to the concave portion of a substrate whose surface includes adjacent concave and convex portions. A processing gas that chemically changes the liquid is supplied to the surface of the substrate, and the liquid is moved from the concave portion to the top surface of the convex portion by a reaction between the processing gas and the liquid, thereby selectively forming a film on the top surface of the convex portion of the substrate surface. The liquid is a liquid halide, a liquid metal, or a liquid polymer or ionic liquid supplied to the concave portion by a spin coating method.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present disclosure relates to a film formation method and a film formation apparatus. [Background technology]

[0002] Patent Document 1 discloses a method for selectively forming a film on a specific region of a substrate without using photolithography. This method involves selectively forming Si adsorption sites on the flat surface of the substrate, out of the flat surface of the substrate and the wall surfaces of a trench recessed from the flat surface. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Publication No. 2018-117038 Summary of the Invention [Problem to be solved by the invention]

[0004] One aspect of the present disclosure provides a technique for selectively forming a film on the top surfaces of the protrusions on a substrate surface that includes adjacent protrusions and recesses. [Means for solving the problem]

[0005] A film forming method according to one aspect of the present disclosure includes the following steps: supplying a liquid into the recesses of a substrate having adjacent recesses and protrusions on its surface; supplying a process gas that chemically changes the liquid to the surface of the substrate, causing the liquid to move from the recesses to the top surfaces of the protrusions through a reaction between the process gas and the liquid, and selectively forming a film on the top surfaces of the protrusions on the surface of the substrate; the liquid is a liquid halide, a liquid metal, or a liquid polymer or ionic liquid that is supplied to the recesses by a spin coating method. [Effects of the Invention]

[0006] According to one aspect of the present disclosure, a film can be selectively formed on the top surfaces of the convex portions of a substrate surface including adjacent concave and convex portions. [Brief explanation of the drawings]

[0007] [Figure 1] FIG. 1 is a flowchart showing a film forming method according to one embodiment. [Figure 2] Figure 2 is a cross-sectional view showing an example of a substrate, where (A) is a cross-sectional view showing after step S1 but before step S2, (B) is a cross-sectional view showing during step S2, and (C) is a cross-sectional view showing after step S2. [Figure 3] FIG. 3 is a cross-sectional view showing a film forming apparatus according to an embodiment. [Figure 4] FIG. 4 is a flowchart showing a modification of the film forming method of FIG. [Figure 5] Figure 5 shows SEM photographs of the substrate of Example 1, where (A) is an SEM photograph after step S1 but before step S2, (B) is an SEM photograph during step S2, and (C) is an SEM photograph after step S2. [Figure 6] FIG. 6 shows SEM photographs of the substrate according to Example 2, where (A) is an SEM photograph after step S1 but before S2, and (B) is an SEM photograph after step S2. [Figure 7] FIG. 7 is a diagram showing the relationship between the processing time of step S4 (Table 2) according to Example 3 and the thickness of the liquid in the recess. [Figure 8] Figure 8(A) is an SEM photograph of the substrate according to Example 4 after processing, Figure 8(B) is an SEM photograph of the substrate according to Example 5 after processing, Figure 8(C) is an SEM photograph of the substrate according to Example 6 after processing, and Figure 8(D) is an SEM photograph of the substrate according to Example 7 after processing. [Figure 9] Figure 9(A) is an SEM photograph of the substrate according to Example 8 after processing, Figure 9(B) is an SEM photograph of the substrate according to Example 9 after processing, and Figure 9(C) is an SEM photograph of the substrate according to Example 10 after processing. [Figure 10]FIG. 10(A) is an SEM photograph of the substrate according to Example 11 after processing, and FIG. 10(B) is an SEM photograph of the substrate according to Example 12 after processing. [Figure 11] FIG. 11(A) is an SEM photograph of the substrate according to Example 13 after processing, and FIG. 11(B) is an SEM photograph of the substrate according to Example 14 after processing. [Figure 12] FIG. 12 is an SEM photograph of the substrate according to Example 17 after processing. [Figure 13] FIG. 13 is an SEM photograph of the substrate according to Example 18 after processing. DETAILED DESCRIPTION OF THE INVENTION

[0008] Hereinafter, embodiments of the present disclosure will be described with reference to the drawings. In the drawings, the same or corresponding components are denoted by the same reference numerals, and descriptions thereof may be omitted.

[0009] An example of a film formation method will be described with reference to FIG. 1. The film formation method includes steps S1 and S2. In step S1, as shown in FIG. 2(A), liquid L is supplied to the concave portions Wb of the concave portions Wb and convex portions We that constitute the substrate surface Wa. The liquid L may be supplied directly to the concave portions Wb, or may be supplied to the concave portions Wb from the top surfaces Wd of the convex portions. The liquid L may also overflow from the concave portions Wb and cover the top surfaces Wd of the convex portions. The substrate surface Wa includes the bottom surfaces of the concave portions, the side surfaces of the concave portions, and the top surfaces Wd of the convex portions. The top surfaces Wd of the convex portions are flat surfaces, and the concave portions Wb are recessed from the top surfaces Wd of the convex portions.

[0010] The substrate W includes, for example, a base substrate W1 including a silicon wafer or the like, and an uneven film W2 formed on the base substrate W1. The uneven film W2 forms recesses Wb and protrusions Wc. The recesses Wb are trenches, via holes, or the like. In this embodiment, the recesses Wb penetrate the uneven film W2, but they do not have to penetrate through it. The protrusions Wc may be pillars or the like. In this embodiment, the uneven film W2 is an insulating film, but may also be a conductive film or a semiconductor film. However, the recesses Wb and protrusions Wc may also be formed on the surface of a silicon wafer.

[0011] The liquid L preferably has a strong intermolecular force. The stronger the intermolecular force, the stronger the cohesive force. If the cohesive force of the liquid L is strong, evaporation of the liquid L can be prevented. The intermolecular force of the liquid L is, for example, 30 kJ / mol or more.

[0012] The liquid L is, for example, a halide. The liquid halide is formed, for example, by a reaction between a source gas of the halide and a reactive gas that reacts with the source gas. The generation of the liquid L may be promoted by plasmatizing both the source gas and the reactive gas, or the reactive gas. The gas is, for example, TiCl4 gas, and the reactive gas is, for example, H2 gas.

[0013] TiCl4 gas and H2 gas are generally used to form a Ti film, not to form a liquid L. The Ti film is formed by, for example, a CVD (Chemical Vapor Deposition) method or an ALD (Atomoic Layer Deoposition) method. In the CVD method, TiCl4 gas and H2 gas are simultaneously supplied to a substrate W. On the other hand, in the ALD method, TiCl4 gas and H2 gas are alternately supplied to a substrate W. According to the CVD method or the ALD method, it is estimated that the following formulas (1) to (3) contribute to the formation of a Ti film. TiCl4+H2→TiH x Cl y ···(1) TiH x Cl y →TiCl2+HCl (2) TiCl2 + H2 → Ti + HCl (3) In the above formulas (2) and (3), TiCl2 may be TiCl or TiCl3.

[0014] In forming the Ti film, the temperature of the substrate W is controlled to 400° C. or higher. As a result, the reactions of the above formulas (1) to (3) proceed sequentially, and the Ti film is formed.

[0015] On the other hand, in forming the liquid L, the temperature of the substrate W is controlled to -100°C to 390°C, preferably 20°C to 350°C. As a result, the reaction of the above formula (2) and the reaction of the above formula (3) are suppressed, and TiH x Cl y A liquid L containing Ti, TiCl, TiCl2, TiCl3, or TiCl4 is formed. The liquid may contain Ti, TiCl, TiCl2, TiCl3, or TiCl4. The temperature of the substrate W only needs to be lower than the decomposition point of the liquid L.

[0016] The source gas is not limited to TiCl4 gas. For example, the source gas may be a silicon halide gas such as SiCl4 gas, Si2Cl6 gas, or SiHCl3 gas, or a metal halide gas such as WCl4 gas, VCl4 gas, AlCl3 gas, MoCl5 gas, SnCl4 gas, or GeCl4 gas. The source gas may contain a halogen, and the halogen may include bromine (Br), iodine (I), or fluorine (F) instead of chlorine (Cl). With these source gases, if the temperature of the substrate W is low, the same reaction as that of formula (1) above will mainly proceed, thereby forming a halide liquid L.

[0017] Furthermore, the reactive gas is not limited to H2 gas. Any reactive gas may be used as long as it can react with the source gas to form liquid L. For example, the reactive gas may be D2 gas. The reactive gas may be supplied together with an inert gas such as argon gas.

[0018] Step S1 includes, for example, simultaneously supplying a source gas and a reactive gas to the substrate W. In this case, step S1 may further include converting both the source gas and the reactive gas into plasma. By converting them into plasma, the reaction between the source gas and the reactive gas can be promoted. Furthermore, by converting them into plasma, the liquid L can be easily formed at a low substrate temperature.

[0019] In this embodiment, step S1 includes simultaneously supplying the source gas and the reactive gas to the substrate W, but may also include alternately supplying the source gas and the reactive gas to the substrate W. In the latter case, step S1 may further include converting the reactive gas into plasma. By converting the reactive gas into plasma, the reaction between the source gas and the reactive gas can be promoted. Furthermore, by converting the reactive gas into plasma, it becomes easier to form the liquid L at a low substrate temperature. Alternatively, step S1 may include supplying only the source gas to the substrate W.

[0020] The liquid L may be any liquid having strong intermolecular forces, such as an ionic liquid, a liquid metal, or a liquid polymer. The metal may be a pure metal or an alloy. The polymer may be, for example, Si2Cl6 gas, SiCl4 gas, SiHCl3 gas, SiH2Cl2 gas, SiH3Cl gas, SiH4 gas, Si2H6 gas, Si3H8 gas, or Si4H 10 The liquid L may be an oligomer or polymer formed by polymerizing two or more molecules of a gas, such as cyclohexasilane gas, tetraethoxysilane (TEOS) gas, dimethyldiethoxysilane (DMDEOS) gas, 2,4,6,8-tetramethylcyclotetrasiloxane (TMCTS) gas, or trisilylamine (TSA) gas, and may be, for example, polysiloxane, polysilane, or polysilazane. The liquid L may also be silanol or the like. The liquid L is supplied to the recess Wb of the substrate W by a spin coating method, or is synthesized inside a processing vessel that accommodates the substrate W and supplied to the recess Wb of the substrate W.

[0021] In step S2, as shown in FIGS. 2(B) and 2(C), a process gas G that chemically changes the liquid L is supplied to the substrate surface Wa. The reaction between the process gas G and the liquid L causes the liquid L to move from the recesses Wb to the top surfaces Wd of the convex portions, selectively forming a film W3 on the top surfaces Wd of the convex portions of the substrate surface Wa. A thin film W3 may also be formed on the side surfaces or bottom surfaces of the recesses. The film W3 may be solid or viscous. The thickness of the film W3 can be controlled by the amount of liquid L supplied and the number of cycles, as described below.

[0022] The processing gas G is supplied, for example, from above the substrate surface Wa and reacts with the liquid L. The liquid L reacts with the processing gas G and undergoes a chemical change. Because the chemical change progresses gradually from the surface of the liquid L, a difference in surface tension occurs, and volume expansion or contraction occurs from the surface of the liquid L, making the liquid L unstable and generating convection. Because the surface of the liquid L changes into a substance with strong surface tension through the reaction with the processing gas G, the liquid L moves toward the top surfaces Wd of the convex portions. Furthermore, the liquid L moves toward the top surfaces Wd of the convex portions, dragged by the increase or decrease in volume due to the chemical change on the surface of the liquid L. The liquid L eventually moves to the top surfaces Wd of the convex portions through the reaction with the processing gas G.

[0023] During the chemical change of the liquid L, the reaction between the liquid L and the processing gas G causes outgassing from the liquid L. The movement of the liquid L caused by the outgassing is also considered to be a factor contributing to the movement of the liquid L. In addition, minute vibrations of the substrate W are also considered to be a factor contributing to the movement of the liquid L.

[0024] The process gas G contains elements that are incorporated into the liquid L, for example, by reaction with the liquid L. That is, the process gas G contains elements that are incorporated into the film W3. For example, oxygen from the process gas G is incorporated into the liquid L, resulting in a film W3 that is an oxide. Alternatively, nitrogen from the process gas G is incorporated into the liquid L, resulting in a film W3 that is a nitride. It is sufficient that the elements in the process gas G are incorporated into the liquid L, and in the process, the elements that make up the liquid L may be degassed.

[0025] For example, the process gas G includes an oxygen-containing gas. The oxygen-containing gas includes oxygen as an element to be incorporated into the liquid L. The oxygen-containing gas may further include nitrogen as an element to be incorporated into the liquid L. The oxygen-containing gas includes, for example, O gas, O gas, H O gas, NO gas, or N O gas.

[0026] The process gas G may include a nitrogen-containing gas. The nitrogen-containing gas includes nitrogen as an element to be incorporated into the liquid L. The nitrogen-containing gas includes, for example, N2 gas, NH3 gas, N2H4 gas, or N2H2 gas.

[0027] The process gas G may include a hydride gas, which includes an element bonded to hydrogen, such as Si, Ge, B, C, or P, as an element to be incorporated into the liquid L. The hydride gas may include, for example, a hydrocarbon gas such as SiH gas, SiH gas, GeH gas, BH gas, or CH gas, or PH gas.

[0028] The processing gas G may degas elements constituting the liquid L by reacting with the liquid L. For example, the processing gas G includes a reducing gas. The reducing gas is, for example, hydrogen (H2) gas or deuterium (D2) gas.

[0029] The process gas G may be supplied together with an inert gas such as argon gas.

[0030] Step S2 may include converting the processing gas G into plasma. By converting the processing gas G into plasma, the reaction between the processing gas G and the liquid L can be promoted.

[0031] In the substrate processing method shown in FIG. 1, steps S1 and S2 are performed once, but steps S1 and S2 may be repeated multiple times. The number of times steps S1 and S2 are repeated is also referred to as the number of cycles. The thickness of film W3 can be controlled by the number of cycles. The number of cycles is set in advance.

[0032] Next, the film forming apparatus 1 will be described with reference to Fig. 3. The film forming apparatus 1 includes a substantially cylindrical airtight processing chamber 2. An exhaust chamber 21 is provided in the center of the bottom wall of the processing chamber 2. The exhaust chamber 21 has, for example, a substantially cylindrical shape that protrudes downward. An exhaust pipe 22 is connected to the exhaust chamber 21, for example, at a side surface of the exhaust chamber 21.

[0033] An exhaust unit 24 is connected to the exhaust pipe 22 via a pressure adjustment unit 23. The pressure adjustment unit 23 includes a pressure adjustment valve such as a butterfly valve. The exhaust pipe 22 is configured so that the pressure inside the processing vessel 2 can be reduced by the exhaust unit 24. A transfer port 25 is provided on the side of the processing vessel 2. The transfer port 25 is opened and closed by a gate valve 26. The substrate W is loaded and unloaded between the processing vessel 2 and a transfer chamber (not shown) via the transfer port 25.

[0034] A stage 3 is provided within the processing vessel 2. The stage 3 is a holder that holds the substrate W horizontally with its surface Wa facing upward. The stage 3 is formed in a substantially circular shape in a plan view and is supported by a support member 31. A substantially circular recess 32 is formed in the surface of the stage 3 for placing the substrate W, for example, with a diameter of 300 mm. The recess 32 has an inner diameter slightly larger than the diameter of the substrate W. The depth of the recess 32 is configured to be substantially the same as the thickness of the substrate W, for example. The stage 3 is made of a ceramic material such as aluminum nitride (AlN). Alternatively, the stage 3 may be made of a metal material such as nickel (Ni). Instead of the recess 32, a guide ring that guides the substrate W may be provided around the periphery of the surface of the stage 3.

[0035] A grounded lower electrode 33 is embedded in the stage 3, for example. A heating mechanism 34 is embedded below the lower electrode 33. The heating mechanism 34 receives power from a power supply (not shown) based on a control signal from the control unit 100, thereby heating the substrate W placed on the stage 3 to a set temperature. If the entire stage 3 is made of metal, the entire stage 3 functions as the lower electrode, and the lower electrode 33 does not need to be embedded in the stage 3. The stage 3 is provided with a plurality of (e.g., three) lift pins 41 for holding and elevating the substrate W placed on the stage 3. The lift pins 41 may be made of, for example, ceramics such as alumina (Al2O3), quartz, or the like. The lower ends of the lift pins 41 are attached to a support plate 42. The support plate 42 is connected to a lift mechanism 44 provided outside the processing chamber 2 via a lift shaft 43.

[0036] The lifting mechanism 44 is installed, for example, below the exhaust chamber 21. The bellows 45 is provided between the lifting mechanism 44 and an opening 211 for the lifting shaft 43 formed in the lower surface of the exhaust chamber 21. The support plate 42 may be shaped so that it can be raised and lowered without interfering with the support member 31 of the stage 3. The lifting pins 41 are configured to be able to be raised and lowered by the lifting mechanism 44 between above and below the surface of the stage 3.

[0037] A gas supply unit 5 is provided on the ceiling wall 27 of the processing chamber 2 via an insulating member 28. The gas supply unit 5 serves as an upper electrode and faces the lower electrode 33. A high-frequency power supply 512 is connected to the gas supply unit 5 via a matching unit 511. By supplying high-frequency power of 450 kHz to 2.45 GHz, preferably 450 kHz to 100 MHz, from the high-frequency power supply 512 to the upper electrode (gas supply unit 5), a high-frequency electric field is generated between the upper electrode (gas supply unit 5) and the lower electrode 33, and capacitively coupled plasma is generated. The plasma generation unit 51 includes the matching unit 511 and the high-frequency power supply 512. Note that the plasma generation unit 51 is not limited to a capacitively coupled plasma, and may be one that generates other types of plasma, such as an inductively coupled plasma.

[0038] The gas supply unit 5 includes a hollow gas supply chamber 52. A number of holes 53 are arranged, for example, evenly, on the bottom surface of the gas supply chamber 52 for dispersively supplying the processing gas into the processing vessel 2. A heating mechanism 54 is embedded in the gas supply unit 5, for example, above the gas supply chamber 52. The heating mechanism 54 is heated to a set temperature by receiving power from a power supply unit (not shown) based on a control signal from the control unit 100.

[0039] A gas supply passage 6 is provided in the gas supply chamber 52. The gas supply passage 6 is in communication with the gas supply chamber 52. Gas sources G61, G62, G63, and G64 are connected upstream of the gas supply passage 6 via gas lines L61, L62, L63, and L64, respectively.

[0040] The gas source G61 is a TiCl4 gas source and is connected to the gas supply path 6 via a gas line L61. A mass flow controller M61, a storage tank T61, and a valve V61 are provided on the gas line L61 in this order from the gas source G61 side. The mass flow controller M61 controls the flow rate of the TiCl4 gas flowing through the gas line L61. With the valve V61 closed, the storage tank T61 stores the TiCl4 gas supplied from the gas source G61 via the gas line L61, thereby increasing the pressure of the TiCl4 gas in the storage tank T61. The valve V61 opens and closes to supply and cut off the TiCl4 gas to the gas supply path 6.

[0041] The gas source G62 is an Ar gas source and is connected to the gas supply path 6 via a gas line L62. A mass flow controller M62 and a valve V62 are provided on the gas line L62, in this order from the gas source G62 side. The mass flow controller M62 controls the flow rate of Ar gas flowing through the gas line L62. The valve V62 opens and closes to supply and cut off Ar gas to the gas supply path 6.

[0042] The gas source G63 is an O2 gas source and is connected to the gas supply path 6 via a gas line L63. A mass flow controller M63 and a valve V63 are provided on the gas line L63 in this order from the gas source G63 side. The mass flow controller M63 controls the flow rate of O2 gas flowing through the gas line L63. The valve V63 opens and closes to supply and cut off the O2 gas to the gas supply path 6.

[0043] The gas source G64 is a H2 gas source and is connected to the gas supply path 6 via a gas line L64. A mass flow controller M64 and a valve V64 are provided on the gas line L64, in this order from the gas source G64 side. The mass flow controller M64 controls the flow rate of H2 gas flowing through the gas line L64. The valve V64 opens and closes the supply of H2 gas to the gas supply path 6.

[0044] The film forming apparatus 1 includes a control unit 100 and a storage unit 101. The control unit 100 includes a CPU, RAM, ROM, etc. (none of which are shown), and performs overall control of the film forming apparatus 1 by, for example, having the CPU execute a computer program stored in the ROM or storage unit 101. Specifically, the control unit 100 performs a film forming process on the substrate W by having the CPU execute a control program stored in the storage unit 101 and controlling the operation of each component of the film forming apparatus 1.

[0045] Next, the operation of the film forming apparatus 1 will be described with reference to Figure 3 again. First, the control unit 100 opens the gate valve 26 and causes the transfer mechanism to transfer the substrate W into the processing chamber 2 and place it on the stage 3. The substrate W is placed horizontally with its front surface Wa facing up. The control unit 100 retracts the transfer mechanism from the processing chamber 2 and then closes the gate valve 26. Next, the control unit 100 heats the substrate W to a predetermined temperature using the heating mechanism 34 of the stage 3 and adjusts the pressure inside the processing chamber 2 to a predetermined pressure using the pressure adjustment unit 23.

[0046] 1, the control unit 100 opens the valves V61, V62, and V64 to simultaneously supply TiCl4 gas, Ar gas, and H2 gas into the processing chamber 2. The valve V63 is closed. The reaction between the TiCl4 gas and the H2 gas produces TiH x Cl y The liquid L is supplied to the recess Wb of the substrate W.

[0047] Specific processing conditions in step S1 are as follows, for example: TiCl4 gas flow rate: 1sccm to 100sccm Ar gas flow rate: 10 sccm to 100,000 sccm, preferably 100 sccm to 20,000 sccm H2 gas flow rate: 1 sccm to 50,000 sccm, preferably 10 sccm to 10,000 sccm Processing time: 1 second to 1800 seconds Treatment temperature: -100°C to 390°C, preferably 20°C to 350°C Treatment pressure: 0.1 Pa to 10,000 Pa, preferably 0.1 Pa to 2,000 Pa.

[0048] In step S1, the control unit 100 may generate plasma using the plasma generation unit 51 to promote the reaction between the TiCl4 gas and the H2 gas. When the TiCl4 gas and the H2 gas are supplied simultaneously, the control unit 100 converts both the TiCl4 gas and the H2 gas into plasma.

[0049] In step S1, the control unit 100 may alternately supply TiCl4 gas and H2 gas into the processing chamber 2 instead of simultaneously supplying them. In this case, the control unit 100 may generate plasma from only the H2 gas among the TiCl4 gas and the H2 gas.

[0050] After step S1, the valves V61 and V64 are closed. At this time, the valve V62 is open, so that Ar is supplied into the processing vessel 2, and the gas remaining in the processing vessel 2 is exhausted to the exhaust pipe 22, and the inside of the processing vessel 2 is replaced with an Ar atmosphere.

[0051] 1, the control unit 100 opens the valve V63 to supply O gas together with Ar gas into the processing chamber 2. The reaction between the O gas and the liquid L causes the liquid L to move from the recesses Wb to the top surfaces Wd of the convex portions, and a film W3 is selectively formed on the top surfaces Wd of the convex portions.

[0052] Specific processing conditions in step S2 are as follows, for example: O2 gas flow rate: 1 sccm to 100,000 sccm, preferably 1 sccm to 10,000 sccm Ar gas flow rate: 10 sccm to 100,000 sccm, preferably 100 sccm to 20,000 sccm Processing time: 1 second to 1800 seconds Treatment temperature: -100°C to 390°C, preferably 20°C to 350°C Treatment pressure: 0.1 Pa to 10,000 Pa, preferably 0.1 Pa to 2,000 Pa.

[0053] In step S2, the control unit 100 may generate plasma using the plasma generating unit 51 to promote the reaction between the O 2 gas and the liquid L.

[0054] After step S2, the control unit 100 unloads the substrate W from the processing vessel 2 in the reverse order of the procedure for loading the substrate W into the processing vessel 2. Note that the control unit 100 may repeat steps S1 and S2 a preset number of times.

[0055] Next, a modified example of the film formation method will be described with reference to FIG. 4. The film formation method of this modified example includes step S3 in addition to steps S1 and S2 shown in FIG. 1. In step S3, the film W3 formed in step S2 is modified. The modified film W3 has better chemical resistance than the unmodified film W3. For example, the modified film W3 has a lower etching rate with respect to dilute hydrofluoric acid (DHF) than the unmodified film W3.

[0056] The modification of the film W3 includes, for example, at least one of the following (A) to (B): (A) Reducing halogen elements or hydrogen elements in the film W3. (B) Densifying the film W3. Densifying the film W3 can be achieved, for example, by terminating dangling bonds in the film W3 with elements contained in the modifying gas or by promoting bonding between existing elements in the film W3.

[0057] In step S3, a modifying gas may be supplied to the film W3. If the modifying gas in S3 and the processing gas G in S2 are the same gas, they are supplied under different conditions. Specifically, for example, the modifying gas is converted into plasma, while the processing gas G is not converted into plasma. Alternatively, the modifying gas is supplied at a higher temperature or at a higher pressure than the processing gas G.

[0058] However, the modifying gas S3 and the processing gas G S2 may be different gases. For example, the processing gas G is nitrogen gas that is plasmatized, while the modifying gas is ammonia (NH3) gas that is plasmatized or hydrazine (N2H4) gas. Alternatively, the processing gas G is oxygen (O2) gas, while the processing gas G is ozone (O3) gas or water vapor (H2O).

[0059] In step S2, the liquid L is moved to the convex top surface Wd, and in step S3, the film W3 is made to have the desired performance. Note that the control unit 100 may repeat steps S1 to S3 a preset number of times.

[0060] [Example] Next, an example will be described.

[0061] <Examples 1 and 2> In Examples 1 and 2, steps S1 and S2 were performed under the processing conditions shown in Table 1 using the film forming apparatus 1 shown in FIG.

[0062] [Table 1]

[0063] In Table 1, "top surface of convex portion" refers to the material of the top surface Wd of the convex portion, which is the material of the uneven film W2. The material of the side surface of the concave portion is the same as the material of the top surface Wd of the convex portion. "bottom surface of concave portion" refers to the material of the bottom surface of the concave portion, which is the material of the upper surface of the base substrate W1. Furthermore, "0" for various gases means that the various gases were supplied, and "ON" for "RF" means that the gas was converted into plasma by high-frequency power. Furthermore, "number of cycles" refers to the number of times steps S1 and S2 were repeated. The same applies to Tables 2 to 8 described below.

[0064] FIG. 5 shows an SEM photograph of substrate W-1 in Example 1. As shown in FIG. 5(A), liquid L-1 was supplied to recess Wb-1 in step S1. The amount of liquid L-1 supplied was just enough to fit inside recess Wb-1. Furthermore, as shown in FIG. 5(B), when the process was interrupted during step S2, specifically when the process time for step S2 was 10 seconds, a similar phenomenon to that shown in FIG. 2(B) was observed, that is, liquid L-1 creeping up from recess Wb-1 toward the top surface Wd-1 of the convex portion. Furthermore, as shown in FIG. 5(C), a film W3-1 was selectively formed on the top surface Wd-1 of the convex portion in step S2.

[0065] Figure 6 shows an SEM photograph of substrate W-2 in Example 2. As shown in Figure 6(A), liquid L-2 was supplied to recesses Wb-2 in step S1. In Example 2, the processing time of step S1 was longer than in Example 1, and a larger amount of liquid L-2 was supplied, so liquid L-2 was supplied not only to recesses Wb-2 but also to the top surfaces Wd-2 of the convex portions. Furthermore, as shown in Figure 6(B), a film W3-2 was selectively formed on the top surfaces Wd-2 of the convex portions in step S2.

[0066] Example 3 3, step S1 was performed under the processing conditions shown in Table 2, and then step S4 was performed under the processing conditions shown in Table 2 without performing step S2. In step S4, only Ar gas was supplied into the processing vessel 2, and the change in the liquid L in the recess Wb was observed.

[0067] [Table 2]

[0068] 7 shows the relationship between the processing time of step S4 in Example 3 and the thickness of the liquid L in the recesses Wb. As is clear from FIG. 7, even when left in a reduced-pressure atmosphere for a long time, no movement or decrease in the liquid L in the recesses Wb was observed. This means that the liquid L does not move until the reaction between the liquid L and the processing gas G begins, and that the liquid L is difficult to evaporate due to its strong intermolecular forces and cohesive forces.

[0069] <Examples 4 to 7> In Examples 4 to 7, steps S1 and S2 were performed under the processing conditions shown in Table 3 using the film forming apparatus 1 shown in FIG.

[0070] [Table 3]

[0071] 8(A) shows an SEM photograph of the substrate W-4 after processing in Example 4. In Example 4, steps S1 and S2 were each performed once, as in Example 1. As a result, a film W3-4 was selectively formed on the top surface Wd-4 of the convex portion out of the concave portion Wb-4 and the convex portion Wd-4.

[0072] 8(B) shows an SEM photograph of the substrate W-5 after processing in Example 5. In Example 5, unlike Example 1, steps S1 and S2 were each performed 10 times. As a result, a film W3-5 was selectively formed on the top surface Wd-5 of the convex portion out of the concave portion Wb-5 and the top surface Wd-5 of the convex portion.

[0073] 8(C) shows an SEM photograph of the substrate W-6 after processing in Example 6. Unlike Example 1, Example 6 was different in that H2O gas was supplied into the processing chamber 2 instead of O2 gas in step S2. As a result, a film W3-6 was selectively formed on the top surface Wd-6 of the convex portion out of the concave portion Wb-6 and the convex portion Wd-6.

[0074] 8(D) shows an SEM photograph of the substrate W-7 according to Example 7 after processing. Unlike Example 1, Example 7 differs in that N gas was supplied into the processing chamber 2 instead of O gas in step S2. The N gas was also plasmatized. As a result, a film W3-7 was selectively formed on the top surface Wd-7 of the convex portion out of the concave portion Wb-7 and the convex portion Wd-7.

[0075] As is clear from Examples 4 to 7, the film W3 could be selectively formed on the top surfaces Wd of the convex portions using various types of processing gas G.

[0076] <Examples 8 to 12> In Examples 8 to 12, steps S1 and S2 were performed under the processing conditions shown in Table 4 using the film forming apparatus 1 shown in FIG.

[0077] [Table 4]

[0078] 9(A) shows an SEM photograph of substrate W-8 after processing in Example 8. In Example 8, steps S1 and S2 were each performed once under the same conditions as in Example 4, except that the material of the top surfaces of the convex portions and the bottom surfaces of the concave portions was changed to titanium oxide (TiO2). As a result, of the concave portions Wb-8 and the convex portion top surfaces Wd-8, a film W3-8 was selectively formed on the convex portion top surfaces Wd-8.

[0079] 9(B) shows an SEM photograph of the substrate W-9 after processing in Example 9. In Example 9, steps S1 and S2 were each performed once under the same conditions as in Example 4, except that the material of the top surfaces of the convex portions and the bottom surfaces of the concave portions was changed to silicon nitride (SiN). As a result, a film W3-9 was selectively formed on the top surfaces Wd-9 of the convex portions out of the concave portions Wb-9 and the convex portions Wd-9.

[0080] 9(C) shows an SEM photograph of substrate W-10 after processing in Example 10. In Example 10, steps S1 and S2 were each performed once under the same conditions as in Example 4, except that the material of the top surfaces of the convex portions and the bottom surfaces of the concave portions was changed to silicon (Si). As a result, of the concave portions Wb-10 and the top surfaces Wd-10 of the convex portions, a film W3-10 was selectively formed on the top surfaces Wd-10 of the convex portions.

[0081] 10(A) shows an SEM photograph of substrate W-11 after processing in Example 11. In Example 11, steps S1 and S2 were each performed once under the same conditions as in Example 4, except that the material of the top surfaces of the convex portions and the bottom surfaces of the concave portions was changed to carbon (C). As a result, of the concave portions Wb-11 and the top surfaces Wd-11 of the convex portions, a film W3-11 was selectively formed on the top surfaces Wd-11 of the convex portions.

[0082] 10(B) shows an SEM photograph of the substrate W-12 after processing in Example 12. In Example 12, steps S1 and S2 were each performed once under the same conditions as in Example 4, except that the material of the top surfaces of the convex portions was changed to ruthenium (Ru). As a result, a film W3-12 was selectively formed on the top surfaces Wd-12 of the concave portions Wb-12 and the convex portions Wd-12.

[0083] As is clear from Examples 8 to 12, the film W3 could be selectively formed on the top surfaces Wd of the convex portions using substrates W made of various materials.

[0084] <Examples 13 and 14> In Examples 13 and 14, steps S1 and S2 were performed under the processing conditions shown in Table 5 using the film forming apparatus 1 shown in FIG.

[0085] [Table 5]

[0086] 11(A) shows an SEM photograph of the substrate W-13 after processing in Example 13. In Example 13, steps S1 and S2 were each performed once under the same conditions as in Example 4, except that the substrate temperature was changed to 80° C. As a result, a film W3-13 was selectively formed on the top surfaces Wd-13 of the convex portions out of the concave portions Wb-13 and the convex portions Wd-13.

[0087] 11(B) shows an SEM photograph of the substrate W-14 after processing in Example 14. In Example 14, steps S1 and S2 were each performed once under the same conditions as in Example 4, except that the substrate temperature was changed to 200° C. As a result, a film W3-14 was selectively formed on the top surfaces Wd-14 of the convex portions out of the concave portions Wb-14 and the convex portions Wd-14.

[0088] As is clear from Examples 13 and 14, the film W3 could be selectively formed on the top surfaces Wd of the convex portions at various substrate temperatures.

[0089] <Examples 15 and 16> In Example 15, steps S1 and S2 were performed using the film formation apparatus 1 shown in Fig. 3 under the processing conditions shown in Table 6. On the other hand, in Example 16, steps S1 to S3 were performed using the film formation apparatus 1 shown in Fig. 3 under the processing conditions shown in Table 6.

[0090] [Table 6]

[0091] In Example 15, when the film W3 formed on the top surfaces Wd of the convex portions was etched with an aqueous solution having an HF concentration of 0.5 mass%, the etching rate was 762.8 Å / min. On the other hand, in Example 16, when the film W3 formed on the top surfaces Wd of the convex portions was etched with an aqueous solution having an HF concentration of 0.5 mass%, the etching rate was 81.3 Å / min. Therefore, the film W3 was modified by step S3.

[0092] Example 17 In Example 17, steps S1 and S2 were performed under the processing conditions shown in Table 7 using the film forming apparatus 1 shown in FIG.

[0093] [Table 7]

[0094] FIG. 12 shows an SEM photograph of substrate W-17 after processing in Example 17. Unlike Example 1, Example 17 differs from Example 1 in that Si2Cl6 (HCD) was supplied into processing chamber 2 as the source gas instead of TiCl4 in step S1. Furthermore, Ar gas and O2 gas were plasmatized in step S2. Furthermore, steps S1 and S2 were each performed twice. Furthermore, the material of the top surfaces of the convex portions and the bottom surfaces of the concave portions was changed to TiO2. As a result, of the concave portions Wb-17 and the convex portion top surfaces Wd-17, a film W3-17 was selectively formed on the convex portion top surfaces Wd-17. Similar results were obtained when the material of the convex portion top surfaces and the bottom surfaces of the concave portions was changed to SiO2.

[0095] Example 18 In Example 18, steps S1 and S2 were performed under the processing conditions shown in Table 8 using the film forming apparatus 1 shown in FIG.

[0096] [Table 8]

[0097] 13 shows an SEM photograph of the substrate W-18 after processing in Example 18. Unlike Example 1, Example 18 was different in that SnCl4 was supplied into the processing vessel 2 as the source gas in place of TiCl4 in step S1. As a result, of the recesses Wb-18 and the top surfaces Wd-18 of the protrusions, a film W3-18 was selectively formed on the top surfaces Wd-18 of the protrusions.

[0098] As is clear from Examples 17 and 18, the film W3 could be selectively formed on the top surfaces Wd of the convex portions using various source gases.

[0099] Although the embodiments of the film forming method and film forming apparatus according to the present disclosure have been described above, the present disclosure is not limited to the above embodiments. Various changes, modifications, substitutions, additions, deletions, and combinations are possible within the scope of the claims. These naturally fall within the technical scope of the present disclosure. [Explanation of symbols]

[0100] W substrate Wa surface Wb recess Wc convex part Wd Convex top surface W3 membrane L liquid

Claims

1. supplying a liquid to a recess of a substrate having adjacent recesses and protrusions on a surface thereof; supplying a processing gas that chemically changes the liquid to the surface of the substrate, causing the liquid to move from the recesses to the top surfaces of the protrusions by reaction between the processing gas and the liquid, and selectively forming a film on the top surfaces of the protrusions of the surface of the substrate; The film forming method, wherein the liquid is a liquid halide, a liquid metal, or a liquid polymer or ionic liquid supplied to the recess by a spin coating method.

2. the liquid is a liquid halide, 2. The film forming method according to claim 1, wherein supplying the liquid into the recess includes forming the liquid by a reaction between the halide source gas and a reactive gas that reacts with the source gas.

3. supplying the liquid to the recessed portion In the case where the source gas and the reactive gas are supplied simultaneously, the source gas and the reactive gas are both plasma-generated, 3. The film forming method according to claim 2, further comprising converting the reactive gas into plasma when the source gas and the reactive gas are alternately supplied.

4. 4. The film forming method according to claim 1, wherein the processing gas that chemically changes the liquid contains an element that is to be taken up by the liquid.

5. 5. The film forming method according to claim 4, wherein the process gas that chemically changes the liquid includes an oxygen-containing gas.

6. 5. The film forming method according to claim 4, wherein the processing gas that chemically changes the liquid includes a nitrogen-containing gas.

7. The film forming method according to claim 4 , wherein the processing gas that chemically changes the liquid includes a hydride gas.

8. The film forming method according to claim 7 , wherein the hydride contains Si, Ge, B, C, or P.

9. 4. The film forming method according to claim 1, wherein the processing gas that chemically changes the liquid degassing elements that constitute the liquid.

10. The film forming method according to claim 9 , wherein the processing gas that chemically changes the liquid includes a reducing gas.

11. The film forming method according to claim 10 , wherein the reducing gas is hydrogen gas or deuterium gas.

12. 12. The film forming method according to claim 1, wherein selectively forming the film on the top surface of the convex portion includes converting the processing gas that chemically changes the liquid into plasma.

13. 13. The film forming method according to claim 1, further comprising repeatedly supplying the liquid to the recessed portion and selectively forming the film on the top surfaces of the protruding portions.

14. The film forming method according to any one of claims 1 to 13, further comprising modifying the film formed on the top surface of the convex portion.

15. 15. The film forming method according to claim 1, wherein the temperature of the substrate is lower than the decomposition point of the liquid when the liquid is supplied to the recess.

16. A processing vessel; a holder configured to horizontally hold the substrate inside the processing chamber with the surface including the recessed and protruding portions facing upward; a gas supply unit that supplies a source gas, a reactive gas that reacts with the source gas, and a process gas that chemically changes a liquid formed by the reaction of the source gas and the reactive gas to the surface of the substrate held by the holder; a control unit that controls the gas supply unit, The control unit supplying the liquid formed by a reaction between the source gas and the reaction gas into the recess of the substrate; supplying the processing gas to the surface of the substrate, causing the liquid to move from the recesses to the top surfaces of the protrusions by reaction between the processing gas and the liquid, and selectively forming a film on the top surfaces of the protrusions of the surface of the substrate; and The film forming apparatus, wherein the liquid is a liquid halide or a liquid metal.

17. A processing vessel; a holder configured to horizontally hold the substrate inside the processing chamber with the surface including the recessed and protruding portions facing upward; a gas supply unit that supplies a process gas to the surface of the substrate held by the holder, the process gas causing a chemical reaction of the liquid that has been previously supplied to the recess by a spin coating method; a control unit that controls the gas supply unit, The control unit holding the substrate, on which the liquid has been supplied in advance to the recess by a spin coating method, on the holding part; supplying the processing gas to the surface of the substrate, causing the liquid to move from the recesses to the top surfaces of the protrusions by reaction between the processing gas and the liquid, and selectively forming a film on the top surfaces of the protrusions of the surface of the substrate; and The film forming apparatus, wherein the liquid is a liquid polymer or an ionic liquid.

18. 18. The film forming apparatus according to claim 16, further comprising a plasma generating unit configured to generate plasma inside the processing chamber.

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