Substrate processing method and substrate processing device

Abstract

To provide a substrate processing method and a substrate processing device that improve a pattern of a photoresist film.SOLUTION: There is provided a substrate processing method that has the processes of: preparing a substrate which has a photoresist film including a metal oxide including a first metal element; performing exposure processing and development processing on the substrate to form a pattern of an opening on the photoresist film; and supplying a metal-containing gas including a second metal element different from the first metal element to the substrate to form a metal oxide film including the second metal element on a side wall of the photoresist film.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present disclosure relates to a substrate processing method and a substrate processing apparatus. [Background technology]

[0002] Patent document 1 discloses a substrate processing method including a deposition step of depositing a deposition layer on exposed surfaces including vertical sidewalls of an etch mask feature, and an etching step of etching back the deposition layer while selectively leaving the deposition on the vertical sidewalls. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Special Publication No. 2008-524851 Summary of the Invention [Problem to be solved by the invention]

[0004] In one aspect, the present disclosure provides a substrate processing method and a substrate processing apparatus for improving a pattern of a photoresist film. [Means for solving the problem]

[0005] In order to solve the above problem, a substrate processing method is provided, comprising the steps of: preparing a substrate having a photoresist film containing a metal oxide containing a first metal element; subjecting the substrate to exposure and development processes to form an opening pattern in the photoresist film; and supplying a metal-containing gas containing a second metal element different from the first metal element to the substrate to form a metal oxide film containing the second metal element on a side wall of the photoresist film. Effect of the Invention

[0006] According to one aspect, it is possible to provide a substrate processing method and a substrate processing apparatus for improving a pattern of a photoresist film. [Brief description of the drawings]

[0007] [Figure 1] 4 is a flowchart showing an example of a substrate processing method according to the present embodiment. [Diagram 2] 5A to 5C are schematic cross-sectional views of a substrate in each process; [Diagram 3] FIG. 1 is a schematic diagram showing an example of a substrate processing apparatus. [Figure 4] 4 is a flowchart showing an example of a film forming process in the substrate processing apparatus. [Diagram 5] 1 is a schematic cross-sectional view of a photoresist film. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

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

[0009] An example of a substrate processing method according to the present embodiment will be described with reference to Fig. 1 and Fig. 2. Fig. 1 is a flow chart showing an example of the substrate processing method according to the present embodiment. Fig. 2 is a schematic cross-sectional view of a substrate in each process.

[0010] In step S101, a substrate is prepared. Here, the substrate to be prepared includes an undercoat film 310 (see FIG. 2(a)). The undercoat film 310 is a film disposed under a photoresist film 320 (see FIG. 2(a)) described later. The undercoat film 310 is a film to which an opening pattern of the photoresist film 320 is transferred in an etching process (see S107) described later. The undercoat film 310 may be, for example, a silicon-containing film (e.g., a spin on glass (SOG) film, etc.), a carbon-containing film (e.g., a spin on carbon (SOC) film, etc.), etc. The undercoat film 310 may be a laminated film in which a plurality of films, such as a silicon-containing film and a carbon-containing film, are laminated. The undercoat film 310 as a laminated film may have a film such as an anti-reflective film (Bottom Anti-Reflective Coating (BARC)). The undercoat film 310 may be, for example, a film used as a hard mask.

[0011] In step S102, the substrate is subjected to a process for forming a photoresist film 320. Fig. 2(a) is an example of a schematic cross-sectional view of the substrate after the photoresist film 320 is formed.

[0012] Here, a photoresist film 320 is formed on an undercoat film 310. The photoresist film 320 is a film containing a metal oxide containing a first metal element. The photoresist film 320 may be a metal oxide resist containing the first metal element, or a resin resist (chemically amplified resist (CAR)) using a metal oxide containing the first metal element as a sensitizer, and is not limited thereto. Here, the first metal element includes one or more of Sn, W, Te, Zn, Zr, Sb, In, etc. The metal oxide is, for example, SnO x (x is any number), WO x (x is any number), TeO x (x is an arbitrary number), ZnO x (x is any number), ZrO x (x is any number), SbO x (x is any number), InO x(x is any number), etc. In addition, the valence of the first metal element in the photoresist film 320 changes when the photoresist film 320 is exposed to EUV (Extreme Ultraviolet) in an exposure process (see S103) described later. In addition, the photoresist film 320 is a negative type photoresist film.

[0013] In step S103, the substrate is subjected to an exposure process. Fig. 2(b) is an example of a schematic cross-sectional view of the substrate after the exposure process.

[0014] Here, in a nitrogen atmosphere, a photoresist film 320 on the substrate is irradiated with EUV through a photomask (not shown) having a predetermined pattern. As a result, as shown in FIG. 2(b), an exposed portion 321 irradiated with EUV and an unexposed portion 322 not irradiated with EUV are formed in the photoresist film 320.

[0015] In step S104, the substrate is subjected to a development process. Fig. 2(c) is an example of a schematic cross-sectional view of the substrate after the development process.

[0016] Here, the unexposed portion 322 of the photoresist film 320 is selectively removed by a development process. At least one of a wet process and a dry process can be used for the development process. As a result, as shown in FIG. 2(c), the photoresist film 320 (see FIG. 2(a)) becomes a photoresist film 320A having an opening pattern 325. Here, the width of the photoresist film 320A is shorter than the width of the exposed portion 321 (see the dashed line in FIG. 2(c)).

[0017] In step S105, the substrate is annealed. Here, unnecessary substances attached to the side walls of the photoresist film 320 are removed by the annealing. The annealing temperature is set within a temperature range in which the catalytic function of a modified layer 321b1 (see FIG. 5(c)) described later does not change. In other words, the annealing temperature is set within a temperature range in which the valence of the first metal element in the modified layer 321b1 (see FIG. 5(c)) described later does not change. The annealing temperature is, for example, within a range of 60° C. to 250° C. The annealing is not essential and may be omitted.

[0018] In step S106, a process is performed to selectively form a metal oxide film 330 on the sidewall of the photoresist film 320. FIG. 2(d) is an example of a schematic cross-sectional view of the substrate after the metal oxide film 330 is formed. The process of selectively forming the metal oxide film 330 will be described later with reference to FIGS. 3 to 5. This allows the width of the photoresist film 320A to approach a desired width (for example, the width of the exposed portion 321 irradiated with EUV shown in FIG. 2(b)).

[0019] In step S107, the substrate is etched. Here, the photoresist film 320 is used as a mask to etch the base film 310 using an etching gas. For example, when the base film 310 is an SOG film, a CF-based gas or the like is used as the etching gas. As a result, the opening pattern 325 of the photoresist film 320 is transferred to the base film 310, and an opening pattern is formed in the base film 310.

[0020] Next, the process shown in step S106 will be described with reference to FIGS.

[0021] First, an example of a substrate processing apparatus that performs the processing shown in step S106 on the substrate W will be described with reference to Fig. 3. Fig. 3 is a schematic view showing an example of the substrate processing apparatus.

[0022] The substrate processing apparatus includes a processing chamber 1 , a mounting table 2 , a shower head 3 , an exhaust unit 4 , a gas supply unit 5 , and a control unit 6 .

[0023] The processing vessel 1 is made of a metal such as aluminum and has a substantially cylindrical shape. The processing vessel 1 accommodates a substrate W. A loading / unloading port 11 is formed in a side wall of the processing vessel 1 for loading or unloading the substrate W. The loading / unloading port 11 is opened and closed by a gate valve 12. An annular exhaust duct 13 having a rectangular cross section is provided on the main body of the processing vessel 1. A slit 13a is formed along the inner peripheral surface of the exhaust duct 13. An exhaust port 13b is formed in the outer wall of the exhaust duct 13. A ceiling wall 14 is provided on the upper surface of the exhaust duct 13 so as to close the upper opening of the processing vessel 1. The gap between the exhaust duct 13 and the ceiling wall 14 is airtightly sealed by a seal ring 15.

[0024] The mounting table 2 horizontally supports the substrate W in the processing chamber 1. The mounting table 2 has a disk shape larger than the substrate W and is made of a ceramic material such as aluminum nitride (AlN) or a metal material such as an aluminum or nickel alloy. A heater 21 for heating the substrate W is embedded inside the mounting table 2. The heater 21 generates heat when powered by a heater power supply (not shown). The output of the heater 21 is controlled by a temperature signal from a thermocouple (not shown) provided near the upper surface of the mounting table 2, thereby controlling the substrate W to a predetermined temperature. The mounting table 2 is provided with a cover member 22 made of ceramics such as alumina so as to cover the outer circumferential region of the upper surface and the side surfaces.

[0025] The mounting table 2 is supported by a support member 23. The support member 23 extends from the center of the bottom surface of the mounting table 2 to below the processing vessel 1 through a hole formed in the bottom wall of the processing vessel 1, and its lower end is connected to a lifting mechanism 24. The mounting table 2 is raised and lowered by the lifting mechanism 24 between a processing position shown by a solid line in FIG. 3 and a transfer position shown by a two-dot chain line below the processing position where the substrate W can be transferred. A flange 25 is attached to the support member 23 below the processing vessel 1. A bellows 26 is provided between the bottom surface of the processing vessel 1 and the flange 25. The bellows 26 separates the atmosphere inside the processing vessel 1 from the outside air, and expands and contracts with the lifting and lowering operation of the mounting table 2.

[0026] Three wafer support pins 27 (only two shown) are provided near the bottom surface of the processing vessel 1 so as to protrude upward from a lift plate 27a. The wafer support pins 27 are raised and lowered via the lift plate 27a by a lift mechanism 28 provided below the processing vessel 1. The wafer support pins 27 are inserted into through holes 2a provided in the mounting table 2 at the transfer position, and can be protruded and retracted from the upper surface of the mounting table 2. The substrate W is transferred between a transfer robot (not shown) and the mounting table 2 by raising and lowering the wafer support pins 27.

[0027] The shower head 3 supplies a processing gas into the processing chamber 1 in a shower-like manner. The shower head 3 is made of, for example, a metal material, and is disposed facing the mounting table 2. The shower head 3 has approximately the same diameter as the mounting table 2. The shower head 3 includes a main body 31 and a shower plate 32. The main body 31 is fixed to the lower surface of the ceiling wall 14. The shower plate 32 is connected below the main body 31. A gas diffusion space 33 is formed between the main body 31 and the shower plate 32. A gas introduction hole 36 is provided in the gas diffusion space 33 so as to penetrate through the center of the ceiling wall 14 and the main body 31. A ring-shaped protrusion 34 protruding downward is formed on the periphery of the shower plate 32. A large number of gas discharge holes 35 are formed on the flat surface on the inner side of the ring-shaped protrusion 34 of the shower plate 32.

[0028] When the mounting table 2 is in the processing position, a processing space 38 is formed between the mounting table 2 and the shower plate 32, and the upper surface of the cover member 22 and the annular protrusion 34 are adjacent to each other to form an annular gap 39.

[0029] The exhaust unit 4 exhausts the inside of the processing vessel 1. The exhaust unit 4 includes an exhaust pipe 41 and an exhaust mechanism 42. The exhaust pipe 41 is connected to the exhaust port 13b. The exhaust mechanism 42 is connected to the exhaust pipe 41 and includes a vacuum pump, a pressure control valve, etc. The exhaust mechanism 42 exhausts gas inside the processing vessel 1 via the exhaust duct 13 and the exhaust pipe 41.

[0030] The gas supply unit 5 supplies various gases to the shower head 3. The gas supply unit 5 has a gas supply source 51. The gas supply source 51 supplies various process gases from the gas outlet holes 35 via the gas inlet holes 36 and the gas diffusion space 33 to the processing space 38.

[0031] The control unit 6 is, for example, a computer, and includes a CPU (Central Processing Unit), a RAM (Random Access Memory), a ROM (Read Only Memory), an auxiliary storage device, etc. The CPU operates based on a program stored in the ROM or the auxiliary storage device, and controls the operation of the substrate processing apparatus. The control unit 6 may be provided inside or outside the substrate processing apparatus. When the control unit 6 is provided outside the substrate processing apparatus, the control unit 6 can control the substrate processing apparatus via a communication network, such as a wired or wireless communication network.

[0032] Next, an example of a film formation process in the substrate processing apparatus will be described with reference to Fig. 4. Fig. 4 is a flow chart showing an example of a film formation process in the substrate processing apparatus.

[0033] In step S201, a substrate is prepared. Here, the substrate to be prepared has an undercoat film 310 and a photoresist film 320A having an opening pattern 325 formed on the undercoat film 310, as shown in FIG.

[0034] Here, the substrate to be prepared will be described with reference to Fig. 5 while also referring to Fig. 1 and Fig. 2. Fig. 5 is an example of a schematic cross-sectional view of a photoresist film 320.

[0035] FIG. 5(a) is an example of a schematic cross-sectional view of the photoresist film 320A formed in step S102.

[0036] 5B is an example of a schematic cross-sectional view of the photoresist film 320 after the exposure process (S103). Here, in the exposure process of step S103, the dose of EUV photons is smaller than the dose of photons that reacts the entire exposed portion 321. Therefore, in the exposed portion 321, a reaction layer 321a is formed on the center side of the exposed portion 321, and a denatured layer 321b is formed on the outer periphery side of the exposed portion 321. The reaction layer 321a is a region that has been sufficiently exposed to EUV and the valence of the first metal element has been changed by EUV. The denatured layer 321b is a region that has not been exposed to EUV sufficiently and the first metal element whose valence has not been changed remains in a part.

[0037] 5(c) is an example of a schematic cross-sectional view of the photoresist film 320A after the development process (S104). The development process removes the unexposed portion 322 and a part of the denatured layer 321b. This forms the photoresist film 320A having the denatured layer 321b1 on the side wall. Here, the denatured layer 321b1 is made up of the first metal element whose valence has not changed.

[0038] Returning to FIG. 4, in step S202, a metal-containing gas containing a second metal element different from the first metal element is supplied to the substrate as a precursor gas (film forming gas). Here, the control unit 6 controls the gas supply unit 5 to supply a metal-containing gas containing the second metal element into the processing chamber 1. The second metal element includes one or more of Al, Ti, Ga, Ru, Hf, and Sn, W, Te, Zn, Zr, Sb, In, etc., only if they are not used as the first metal element. In other words, when any one of "Sn, W, Te, Zn, Zr, Sb, In" is selected as the first metal element, the second metal element may be selected from "Al, Ti, Ga, Ru, Hf" and "Sn, W, Te, Zn, Zr, Sb, In" excluding the element selected as the first metal element. Examples of the metal-containing gas containing the second metal element include TMA (trimethylaluminum), TDMAT (tetrakis(dimethylamino)titanium), TEGa (triethylgallium), RuCO 12etc. In addition, by setting the temperature lower than the temperature at which the metal-containing gas forms a film by thermal decomposition, formation of metal oxide film 330 on the upper surface of photoresist film 320 and at the bottom of the opening in photoresist film 320 is suppressed.

[0039] In contrast, in the modified layer 321b on the side wall of the photoresist film 320A, the first metal element remaining in the modified layer 321b1, whose valence has not changed, acts as a catalyst to react with a metal-containing gas containing a second metal element, thereby decomposing a precursor of the metal-containing gas, and a metal oxide film (metal-containing film) 330 is selectively formed on the side wall of the photoresist film 320A.

[0040] In step S203, an inert gas is supplied to the substrate. The control unit 6 controls the gas supply unit 5 to supply the inert gas into the processing chamber 1. The inert gas is a gas that is inert to the sidewall of the photoresist film 320A and the metal-containing gas. The inert gas includes at least one of nitrogen (N2) gas, Ar gas, He gas, etc. Here, the metal-containing gas physically adsorbed on the upper surface of the photoresist film 320, the bottom of the opening of the photoresist film 320 (the portion exposed from the opening of the base film 310), etc. is purged with the inert gas.

[0041] In step S204, the control unit 6 judges whether or not the processes of steps S202 and S203 have been repeated a predetermined number of times. If the processes have not been repeated the predetermined number of times (S204: NO), the control unit 6 returns to step S202 and repeats the process. When the thickness of the metal oxide film 330 reaches a predetermined thickness (for example, about 1 nm), the catalytic effect of the modified layer 321b1 disappears and the growth of the metal oxide film 330 stops. This makes it possible to suitably control the thickness of the metal oxide film 330. If the processes have been repeated the predetermined number of times (S204: YES), the control unit 6 ends the process.

[0042] In step S202, a metal-containing gas containing a second metal element is supplied as a precursor gas (film-forming gas) to form a metal oxide film 330 containing a second metal element on the side wall of the photoresist film 320A, but this is not limited thereto. Instead of the metal-containing gas, a semiconductor gas containing one or more semiconductor raw materials (semiconductor elements) of Si, B, Ge, Se, etc. may be supplied into the processing vessel 1 as a precursor gas (film-forming gas) to form a semiconductor film (not shown) containing a semiconductor raw material (semiconductor element) different from the first metal element on the side wall of the photoresist film 320A. That is, in step S202, either one of the metal-containing gas containing the second metal element and the semiconductor gas containing the semiconductor raw material may be supplied. As a result, a semiconductor film (not shown) containing a semiconductor raw material (semiconductor element) may be selectively formed on the side wall of the photoresist film 320A. In addition, this is not limited thereto, and both the metal-containing gas containing the second metal element and the semiconductor gas containing the semiconductor raw material may be supplied in step S202.

[0043] Thus, if the exposure process is performed with a dose of photons smaller than the desired dose for reacting the entire exposed portion 321, the pattern formed in the photoresist film 320A will be narrower than the desired width (see FIGS. 2(c) and 5(c)). In contrast, according to the substrate processing method shown in FIGS. 1 and 4, a metal oxide film 330 is selectively formed on the sidewall of the photoresist film 320A, thereby forming a photoresist film 320A having a desired width. This improves the shape of the opening pattern transferred to the base film 310 in the etching process.

[0044] In other words, the dose of photons in the exposure process can be reduced, the power consumption in the exposure process can be reduced, and the throughput can be improved by reducing the exposure process time.

[0045] Alternatively, the thickness of the denatured layer 321b1 and the amount of the first metal element whose valence has not changed remaining in the denatured layer 321b1 may be adjusted to adjust the film thickness of the metal oxide film 330. Specifically, the thickness of the denatured layer 321b1 and the amount of the first metal element whose valence has not changed remaining in the denatured layer 321b1 are adjusted by adjusting the photon dose and exposure time in the exposure process, the development time in the development process, and the like.

[0046] 3 has been described as an apparatus that performs the selective film formation process (S106), but is not limited thereto. In addition to the selective film formation process (S106), the substrate processing apparatus shown in FIG. 3 may be configured to perform one or more of the development process (S104), the annealing process (S105), and the etching process (S107).

[0047] In addition, the apparatus for performing the development process (S104), the apparatus for performing the annealing process (S105), the apparatus for performing the selective film formation process (S106), and the apparatus for performing the etching process (S107) may each be configured as separate apparatuses, and the substrate processing apparatus may be configured such that these apparatuses are connected by the same transport apparatus.

[0048] The above describes the substrate processing method according to the present embodiment, but the present disclosure is not limited to the above embodiment, and various modifications and improvements are possible within the scope of the gist of the present disclosure described in the claims. [Explanation of symbols]

[0049] 310 Base film 320,320A Photoresist film 321 Exposure Section 321a Reaction layer 321b, 321b1 Modified layer 322 Unexposed area 330 Metal oxide film

Claims

1. preparing a substrate having a photoresist film including a metal oxide including a first metal element; a step of subjecting the substrate to an exposure process and a development process to form an opening pattern in the photoresist film; supplying a metal-containing gas containing a second metal element different from the first metal element to the substrate to form a metal oxide film containing the second metal element on a side wall of the photoresist film; A method for processing a substrate.

2. The exposure process includes: exposing the photoresist film to extreme ultraviolet light to form exposed and unexposed areas in the photoresist film; The exposure section includes: a reaction layer which is a region in which the valence of the first metal element has been changed by the extreme ultraviolet light; a modified layer which is a region in which the first metal element whose valence has not changed remains; The method for processing a substrate according to claim 1 .

3. The development process includes: removing the unexposed area and a portion of the modified layer; The substrate processing method according to claim 2 .

4. The step of forming the metal oxide film includes: forming the metal oxide film containing the second metal element on a side wall of the photoresist film using the first metal element, whose valence has not changed, as a catalyst; The substrate processing method according to claim 3 .

5. adjusting a thickness of the metal oxide film based on a thickness of the modified layer and an amount of the first metal element whose valence has not changed remaining in the modified layer; The substrate processing method according to claim 4 .

6. After the step of forming a pattern of the opening in the photoresist film and before the step of forming the metal oxide film, The method further comprises a step of subjecting the substrate to an annealing treatment within a temperature range in which the valence of the first metal element does not change. The method for processing a substrate according to claim 1 .

7. After the step of forming the metal oxide film, The method further comprises the step of supplying an inert gas to the substrate. The method of claim 1 .

8. The first metal element includes any one of Sn, W, Te, Zn, Zr, Sb, and In; The method for processing a substrate according to claim 1 .

9. The second metal element includes any one of Al, Ti, Ga, Ru, Hf, and Sn, W, Te, Zn, Zr, Sb, and In only when not used as the first metal element; The method of claim 1 .

10. Instead of the step of forming a metal oxide film containing the second metal element, supplying a semiconductor gas containing a semiconductor material to the substrate to form a semiconductor film containing the semiconductor material different from the first metal element on a side wall of the photoresist film; The method for processing a substrate according to claim 1 .

11. The semiconductor raw material contains any one of Si, B, Ge, and Se; The method of claim 10.

12. a mounting table for supporting a substrate having a photoresist film including a metal oxide including a first metal element and an opening pattern formed thereon; a processing vessel that accommodates the mounting table; a gas supply unit for supplying a gas into the processing chamber; A control unit, The control unit is a metal-containing gas containing a second metal element different from the first metal element is supplied into the processing chamber, and a metal oxide film containing the second metal element is formed on a side wall of the photoresist film. Substrate processing equipment.

13. The control unit is A step of supplying an inert gas into the processing chamber is performed. The substrate processing apparatus of claim 12 .

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