Substrate processing method and substrate processing apparatus

Abstract

To appropriately transfer a resist pattern formed by a resist film onto a carbon film with high throughput.SOLUTION: A substrate processing method includes the step of forming a silicon carbide film on a carbon film formed on a substrate, and a resist film containing a metal oxide is formed directly on the silicon carbide film in a step subsequent to the step of forming the silicon carbide film, and a main structural portion in the silicon carbide film having silicon atoms and carbon atoms is an aggregate of portions in which silicon atoms are bonded via carbon atoms.SELECTED DRAWING: Figure 10

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 laminating a carbon film on a substrate to be processed, a silicon-containing intermediate film on the carbon film, and a photoresist film on the intermediate film, and discloses that the carbon film is a spin-on carbon film prepared by a spin coating method. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2013-228447 A Summary of the Invention [Problem to be solved by the invention]

[0004] The technology according to the present disclosure appropriately transfers a resist pattern formed by a resist film to a carbon film with high throughput. [Means for solving the problem]

[0005] One aspect of the present disclosure is a substrate processing method comprising the step of forming a silicon carbide film on a carbon film formed on a substrate, wherein a resist film containing a metal oxide is formed directly on the silicon carbide film in a step subsequent to the step of forming the silicon carbide film, and a main structural portion in the silicon carbide film having silicon atoms and carbon atoms is an aggregate of portions in which silicon atoms are bonded via carbon atoms. Effect of the Invention

[0006] According to the present disclosure, a resist pattern formed by a resist film can be appropriately transferred to a carbon film with high throughput. [Brief description of the drawings]

[0007] [Figure 1] 1 is an explanatory diagram showing an outline of the configuration of a wafer processing system having a coating and developing processing apparatus as a substrate processing apparatus according to an embodiment of the present invention; [Diagram 2] FIG. 2 is an explanatory diagram showing an outline of an internal configuration of a coating and developing treatment apparatus. [Diagram 3] 2 is a diagram showing an outline of the internal configuration of the front side of the coating and developing treatment apparatus; FIG. [Figure 4] 2 is a diagram showing an outline of an internal configuration of a coating and developing treatment apparatus on the rear side; FIG. [Diagram 5] 1A and 1B are diagrams for explaining the structure of a SiC film formed in a coating and developing treatment apparatus. [Figure 6] 1A and 1B are diagrams for explaining the structure of a SiC film formed in a coating and developing treatment apparatus. [Figure 7] FIG. 2 is a vertical cross-sectional view showing an outline of the configuration of a coating unit for a SiC film. [Figure 8] 2 is a cross-sectional view showing an outline of the configuration of a coating unit for a SiC film. FIG. [Figure 9] FIG. 2 is a vertical cross-sectional view showing the outline of the configuration of an irradiation unit. [Figure 10] 1 is a flow chart illustrating major steps of an example of wafer processing. [Figure 11] 3A to 3C are schematic partial cross-sectional views showing states of a wafer W after each process of the wafer processing. [Figure 12] 1 shows an example of a process window that illustrates a difference in a resist pattern caused by changing the type of a film underlying the resist film. [Figure 13] 1 shows an example of a process window that illustrates a difference in a resist pattern caused by changing the type of a film underlying the resist film. [Figure 14] FIG. 1 is a diagram showing the relationship between the hole diameter and the number of shape defects of a pattern when a hole pattern is formed using a chemically amplified EUV resist film. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0008] In the manufacturing process of semiconductor devices, various processes such as photolithography and etching are performed on a semiconductor wafer (hereinafter referred to as "wafer") as a substrate. In the etching process, the etching target is etched using a resist pattern formed in the photolithography process as a mask. Types of etching include wet etching, which uses liquid, and dry etching, which uses gas.

[0009] In dry etching, when the selectivity of the film to be etched relative to the resist pattern is low and the resist pattern is thin, a carbon-containing hard mask film, a silicon-containing film, and a resist film may be laminated in this order on the film to be etched. When laminated in this way, the pattern of the resist pattern is transferred by dry etching to the silicon-containing film, the carbon-containing hard mask film, and the film to be etched in this order. An example of the carbon-containing hard mask film is a spin-on carbon (SoC) film, and an example of the silicon-containing film is a silicon dioxide (SiO 2 ) membrane.

[0010] In recent years, with the increasing integration density of semiconductor devices, there is a demand for finer resist patterns. To achieve this, exposure processing using EUV (Extreme Ultraviolet) light has been proposed. Note that the resist film for EUV needs to be very thin, for example, the film thickness needs to be 50 nm or less.

[0011] In addition, the SoC film is used as a carbon-containing hard mask film, and the SiO film is used as a silicon-containing film. 2 When a SiO2 film and an EUV resist film are laminated in this order, 2 Because the adhesion of the resist film to the undercoat film is low, pattern collapse may occur. Therefore, in order to improve the adhesion of the EUV resist film to the undercoat film, SiO 2An adhesion layer may be formed on the membrane. However, forming an adhesion layer in this way increases the number of steps, and there is room for improvement in terms of throughput.

[0012] Therefore, the technology disclosed herein appropriately transfers a resist pattern made of an EUV resist film to an SoC film with high throughput.

[0013] Hereinafter, a substrate processing apparatus and an inspection method according to the present embodiment will be described with reference to the drawings. In this specification and the drawings, elements having substantially the same functional configurations are denoted by the same reference numerals, and duplicated description will be omitted.

[0014] <Wafer processing system> FIG. 1 is an explanatory diagram showing an outline of the configuration of a wafer processing system having a coating and developing processing apparatus as a substrate processing apparatus according to this embodiment. The wafer processing system 1 in FIG. 1 includes a coating and developing processing apparatus 2, an etching processing apparatus 3, and a control apparatus 4.

[0015] The coating and developing treatment device 2 performs photolithography treatment on the wafer. In the coating and developing treatment device 2, a resist film is formed, etc.

[0016] The etching processing device 3 performs dry etching on the wafer. For example, an RIE (Reactive Ion Etching) device that performs dry etching on the wafer by plasma processing is used as the etching processing device 3. For example, the etching processing device 3 performs etching of an underlying film of a resist film using a resist film as a mask.

[0017] The control device 4 controls the operation of each device. The control device 4 is, for example, a computer equipped with a CPU, memory, etc., and has a program storage unit (not shown). The program storage unit stores a program for controlling the operation of the drive systems of the above-mentioned various processing devices and transport devices (not shown), etc., to realize wafer processing in the wafer processing system 1, which will be described later. The above program may be recorded in a non-transitory computer-readable storage medium H, and may be installed from the storage medium H into the control device 4. A part or all of the program may be realized by dedicated hardware (circuit board).

[0018] <Coating and developing treatment equipment> Fig. 2 is an explanatory diagram showing an outline of the internal configuration of the coating and developing treatment apparatus 2. Figs. 3 and 4 are diagrams showing an outline of the internal configuration of the front side and rear side, respectively, of the coating and developing treatment apparatus 2. Figs. 5 and 6 are diagrams for explaining the structure of a SiC film formed in the coating and developing treatment apparatus 2.

[0019] 2, the coating and developing treatment apparatus 2 has a cassette station 10 where a cassette C containing a plurality of wafers W is carried in and out, and a treatment station 11 equipped with a plurality of various treatment units that perform predetermined treatments on the wafers W. The coating and developing treatment apparatus 2 has a configuration in which the cassette station 10, the treatment station 11, and an interface station 13 that transfers the wafer W between the treatment station 11 and an exposure apparatus 12 adjacent to the treatment station 11 are integrally connected.

[0020] The cassette station 10 is provided with a cassette placement stage 20. The cassette placement stage 20 is provided with a plurality of cassette placement plates 21 on which the cassettes C are placed when the cassettes C are carried in and out of the coating and developing treatment apparatus 2.

[0021] The cassette station 10 is provided with a wafer transport unit 23 that is movable on a transport path 22 that extends in the X direction in the figure. The wafer transport unit 23 is also movable in the up-down direction and around the vertical axis (the θ direction), and can transport wafers W between the cassettes C on each cassette mounting plate 21 and a transfer unit in the third block G3 of the processing station 11, which will be described later.

[0022] The processing station 11 is provided with a plurality of blocks, for example, four blocks G1, G2, G3, and G4, each equipped with various units. For example, a first block G1 is provided on the front side (negative side in the X direction in FIG. 2) of the processing station 11, and a second block G2 is provided on the rear side (positive side in the X direction in FIG. 2) of the processing station 11. A third block G3 is provided on the cassette station 10 side of the processing station 11 (negative side in the Y direction in FIG. 2), and a fourth block G4 is provided on the interface station 13 side of the processing station 11 (positive side in the Y direction in FIG. 2).

[0023] In the first block G1, as shown in FIG. 3, a plurality of liquid processing units, for example, a development processing unit 30, an SoC film coating unit 31, an SiC film coating unit 32, and a resist coating unit 33 are arranged in this order from the bottom.

[0024] The development processing unit 30 develops the wafer W. The SoC film coating unit 31 coats the SoC film material directly on a film to be etched (e.g., a silicon oxide film) formed on the wafer W, to form a coating film of the SoC film material. The coating film of the SoC film material becomes an SoC film when heated by a heat treatment unit 40 described below. The carbon (C) content of the SoC film is 90% or more. In this example, the SoC film coating unit 31 and the heat treatment unit 40 form a "spin-on carbon film forming section."

[0025] The SiC film coating unit 32 coats a silicon carbide (SiC) film material directly on the SoC film formed on the wafer W to form a coating film of the SiC film material. The coating film of the SiC film material becomes a SiC film by heating in a heat treatment unit 40 described below and irradiating with ultraviolet rays in an irradiation unit 41 described below. The C content of the SiC film thus formed is 30% to 70% or more. In this example, the SiC film coating unit 32 and the heat treatment unit 40 constitute a "silicon carbide film forming section." As the SiC film material, for example, a material containing only polycarbosilane is used as a material containing a portion in which a silicon (Si) atom and a carbon (C) atom are bonded, that is, a Si-C bond portion.

[0026] In this embodiment, the SiC film is a film in which the proportion of C atoms is higher than that of oxygen (O) atoms as atoms that bond with Si atoms in the Si-containing film formed on the wafer W. Since the atoms that bond with Si atoms in the Si-containing film formed on the wafer W have a high degree of influence on the properties required of the Si-containing film, the SiC film is formed of, for example, SiO x It is different from films that are expressed by a combination of Si and other elements, such as SiO x The characteristics of a film differ from those of a film that is a combination of Si and other elements, such as a film. The characteristics of a film vary, for example, in terms of the difference in etching resistance with respect to another film stacked above or below the film, or in terms of the reaction when irradiated with light, and can be said to be process factors that can affect the process results in the overall processing steps.

[0027] In this embodiment, the main structural portion of the SiC film, which has both Si atoms and C atoms, is an aggregate P of portions m in which Si atoms are bonded via C atoms, as shown in Fig. 5. Note that, if any portion that is unnecessary for the properties of the film remains in the SiC film, such as an additive contained in the SiC film material, the "main structural portion" does not include the unnecessary portion. More specifically, the main structural portion of the SiC film has the following structure. That is, the main structural portion has a structure in which a plurality of portions m in which Si atoms are bonded via C atoms, which originally existed independently of each other as shown in Fig. 6, are bonded by dehydration condensation as shown in Fig. 5. The portion m in which Si atoms are bonded via C atoms before dehydration condensation is, for example, polycarbosilane. In other words, the SiC film is formed by dehydration condensation of, for example, polycarbosilane in a coating film of the SiC film material. Furthermore, in the main structural portion of the SiC film, atoms bonded to Si atoms do not include O atoms, except for atoms forming siloxane bonds (Si-O-Si bonds), and include C atoms.

[0028] The resist coating unit 33 coats a chemically amplified resist liquid for EUV onto the SiC film formed on the wafer W, forming a coating film of the resist liquid. The coating film of the resist liquid becomes a resist film by heating in a heat treatment unit 40, which will be described later. In this example, the resist coating unit 33 and the heat treatment unit 40 constitute a "resist film forming section."

[0029] For example, three each of the developing processing units 30, the SoC film coating units 31, the SiC film coating units 32, and the resist coating units 33 are arranged in the horizontal direction. The number and arrangement of these developing processing units 30, the SoC film coating units 31, the SiC film coating units 32, and the resist coating units 33 can be selected arbitrarily. In addition, in the SoC film coating unit 31, the SiC film coating unit 32, and the resist coating unit 33, a coating film of an SoC film material, a coating film of an SiC film material, and a coating film of a chemically amplified resist liquid for EUV are formed on the wafer W by a spin coating method (also called a spin coating method).

[0030] As shown in FIG. 4, the second block G2 is provided with a heat treatment unit 40 and an irradiation unit 41.

[0031] The thermal processing unit 40 performs thermal processing on the wafer W, such as heating or cooling. The irradiation unit 41 irradiates ultraviolet light in a low-oxygen atmosphere with an oxygen concentration of 0.1% or less onto the coating film of the SiC film material formed on the wafer W. The irradiation of ultraviolet light by the irradiation unit 41 is performed before the formation of a resist film.

[0032] These heat treatment units 40 and irradiation units 41 are arranged vertically and horizontally, and the number and arrangement thereof can be selected arbitrarily.

[0033] For example, in the third block G3, a plurality of transfer units 50, 51, 52, 53, 54, 55, 56 are provided in this order from the bottom up, while in the fourth block G4, a plurality of transfer units 60, 61, 62 are provided in this order from the bottom up.

[0034] 2, a region surrounded by the first block G1 to the fourth block G4 forms a wafer transfer region D. In the wafer transfer region D, a wafer transfer unit 70 is disposed.

[0035] The wafer transfer unit 70 has a transfer arm 70a that is movable in, for example, the Y direction, the X direction, the θ direction, and the vertical direction. The wafer transfer unit 70 moves within the wafer transfer region D, and can transfer the wafer W between units in the surrounding first block G1, second block G2, third block G3, and fourth block G4. A plurality of wafer transfer units 70 are arranged vertically as shown in, for example, FIG. 4, and can transfer the wafer W between units of approximately the same height in each of the blocks G1 to G4.

[0036] In addition, in the wafer transfer region D, a shuttle transfer unit 80 is provided which linearly transfers the wafer W between the third block G3 and the fourth block G4.

[0037] The shuttle transfer unit 80 is linearly movable, for example, in the Y direction shown in FIG. 4. The shuttle transfer unit 80 moves in the Y direction while supporting the wafer W, and can transfer the wafer W between the transfer unit 52 of the third block G3 and the transfer unit 62 of the fourth block G4.

[0038] As shown in FIG. 2, a wafer transfer unit 90 is provided adjacent to the positive X-direction side of the third block G3. The wafer transfer unit 90 has a transfer arm 90a that is movable, for example, in the X direction, θ direction, and vertical direction. The wafer transfer unit 90 moves vertically while supporting the wafer W, and can transfer the wafer W to each transfer unit within the third block G3.

[0039] An interface station 13 is provided with a wafer transfer unit 100 and a transfer unit 101. The wafer transfer unit 100 has a transfer arm 100a that is movable, for example, in the Y direction, θ direction, and vertical direction. The wafer transfer unit 100 can support the wafer W on the transfer arm 100a, for example, and transfer the wafer W between each transfer unit within the fourth block G4, the transfer unit 101, and the exposure apparatus 12.

[0040] In the coating and developing apparatus 2, each of the above-described processing units and each transfer unit are controlled, for example, by a control device 4.

[0041] <Coating unit for SiC film> Subsequently, the configuration of the above-described coating unit 32 for SiC film will be described. FIGS. 7 and 8 are a longitudinal sectional view and a cross-sectional view, respectively, showing the outline of the configuration of the coating unit 32 for SiC film.

[0042] The coating unit 32 for SiC film has a processing container 120 whose interior can be closed as shown in FIG. 7. On the side surface of the processing container 120, a loading / unloading port 121 for the wafer W is formed as shown in FIG. 8, and an opening / closing shutter 122 is provided at the loading / unloading port 121.

[0043] 7, a spin chuck 130 that holds and rotates the wafer W is provided in the center of the processing vessel 120. The spin chuck 130 has a horizontal upper surface, and the upper surface is provided with, for example, a suction port (not shown) for sucking the wafer W. The wafer W can be sucked and held on the spin chuck 130 by suction from the suction port.

[0044] The spin chuck 130 is connected to a chuck driving mechanism 131 and can be rotated at a desired speed by the chuck driving mechanism 131. The chuck driving mechanism 131 has a rotation driving source (not shown) such as a motor that generates a driving force for rotating the spin chuck 130. The chuck driving mechanism 131 is also provided with an elevation driving source such as a cylinder, and the spin chuck 130 can move up and down.

[0045] A cup 132 is provided around the spin chuck 130 to receive and collect liquid scattered or dropped from the wafer W. A discharge pipe 133 for discharging the collected liquid and an exhaust pipe 134 for exhausting the atmosphere inside the cup 132 are connected to the bottom surface of the cup 132.

[0046] As shown in Fig. 8, a rail 140 extending along the Y direction (left and right direction in Fig. 8) is formed on the negative X direction side (downward in Fig. 8) of cup 132. Rail 140 is formed, for example, from the outside of cup 132 on the negative Y direction side (left direction in Fig. 8) to the outside of cup 132 on the positive Y direction side (right direction in Fig. 8). An arm 141 is attached to rail 140.

[0047] A coating nozzle 142 is supported on the arm 141 as shown in FIG. 7 and FIG. 8. The coating nozzle 142 discharges a SiC film material as a coating liquid. The arm 141 is movable on the rail 140 by a nozzle driving unit 143 shown in FIG. 8. This allows the coating nozzle 142 to move from a waiting unit 144 installed outside the cup 132 on the positive Y-direction side to above the center of the wafer W in the cup 132, and further move on the surface of the wafer W in the radial direction of the wafer W. The arm 141 is also movable up and down by the nozzle driving unit 143, and the height of the coating nozzle 142 can be adjusted. The coating nozzle 142 is connected to a supply unit (not shown) that supplies MSQ to the coating nozzle 142.

[0048] The configurations of the development processing unit 30, the SoC film coating unit 31 and the resist coating unit 33 are similar to the configuration of the SiC film coating unit 32, except that the type of processing liquid discharged from the coating nozzle 142 is different.

[0049] <Irradiation unit> Next, a description will be given of the configuration of the above-mentioned irradiation unit 41. Fig. 9 is a vertical sectional view showing an outline of the configuration of the irradiation unit 41.

[0050] The irradiation unit 41 has a processing container 150 whose interior can be sealed as shown in Fig. 9. A loading / unloading port 151 for a wafer W is formed on one side of the processing container 150 facing the wafer transfer region D, and an opening / closing shutter 152 is provided at the loading / unloading port 151.

[0051] A gas other than oxygen gas, such as N 2 A gas supply port 160 for supplying an inert gas such as a gas is formed, and a gas supply mechanism 162 is connected to the gas supply port 160 via a gas supply pipe 161. The gas supply mechanism 162 has, for example, a flow rate adjustment valve (not shown) for adjusting the flow rate of gas supplied into the processing vessel 150. By introducing a gas other than oxygen gas into the processing vessel 150 using such a gas supply mechanism, the inside of the processing vessel 150 can be made into a low-oxygen atmosphere with an oxygen concentration of 0.1 ppm or less.

[0052] For example, an exhaust port 163 for exhausting the atmosphere inside the processing vessel 150 is formed on the bottom surface of the processing vessel 150, and an exhaust mechanism 165 for exhausting the atmosphere inside the processing vessel 150 is connected to the exhaust port 163 via an exhaust pipe 164. The exhaust mechanism 165 includes an exhaust pump (not shown) and the like. By introducing a gas other than oxygen gas through the gas supply port 160 and exhausting it through the exhaust port 163, the atmosphere within the processing vessel 150 can be quickly replaced with a low-oxygen atmosphere of 0.1 ppm or less.

[0053] A cylindrical support 170 on which a wafer W is horizontally placed is provided inside the processing vessel 150. Lift pins 171 for transferring the wafer W are supported by a support member 172 and installed inside the support 170. The lift pins 171 are provided to pass through through holes 173 formed in an upper surface 170a of the support 170, and three lift pins 171, for example, are provided. A drive mechanism 174 for lifting and lowering the support member 172 to lift and lower the lift pins 171 is provided at a base end of the support member 172. The drive mechanism 174 has a drive source (not shown) such as a motor that generates a drive force for lifting and lowering the support member 172.

[0054] A light source 180, such as a deuterium lamp or an excimer lamp, is provided above the processing vessel 150 to irradiate the wafer W on the support 170 with ultraviolet light having a wavelength of, for example, 172 nm. The light source 180 can irradiate the entire surface of the wafer W with ultraviolet light. A window 181 that transmits ultraviolet light from the light source 180 is provided on a top plate of the processing vessel 150. The wavelength of the ultraviolet light is not limited to 172 nm, and is, for example, 150 nm to 250 nm.

[0055] <Wafer processing> Next, a description will be given of wafer processing performed using the wafer processing system 1 configured as above. FIG. 10 is a flow chart showing the main steps of an example of wafer processing. FIG. 11 is a schematic partial cross-sectional view showing the state of the wafer W after each step of the wafer processing. Note that, as shown in FIG. 11(A), the surface of the wafer W on which the above-mentioned wafer processing is performed has SiO 2 The membrane F1 is preformed.

[0056] In wafer processing using the wafer processing system 1, first, a cassette C storing a plurality of wafers W is carried into a cassette station 10 of the coating and developing treatment apparatus 2. Then, the wafers W in the cassette C are transferred to a treatment station 11, where the temperature is adjusted in a heat treatment unit 40.

[0057] (Step S1) 10 and 11(A), the Si0 2 An SoC film F2 is formed directly on the film F1.

[0058] Specifically, the wafer W is transferred to the SoC film coating unit 31, and the SoC film material is spin-coated on the surface of the wafer W, forming a SiO 2 A coating film of an SoC film material is formed so as to cover the film F1. Next, the wafer W is transferred to the heat treatment unit 40, where the coating film of the SoC film material is heated to form the SoC film F2. The thickness of the formed SoC film F2 is, for example, 50 to 100 nm.

[0059] (Step S2) Subsequently, a SiC film is formed directly on the SoC film F2 formed on the wafer W.

[0060] Specifically, the wafer W is transported to a SiC film coating unit 32, and a SiC film material containing, for example, polysilane carbon is spin-coated onto the surface of the wafer W, forming a coating film F3 of the SiC film material to cover the SoC film F2, as shown in FIG. 11(B). Next, the wafer W is transferred to the heat treatment unit 40, and the wafer W is heated, specifically, the coating film F3 of the SiC film material is heated in the air atmosphere. The heating temperature is, for example, 200° C. to 250° C. After heating, the wafer W is transferred to the irradiation unit 41. Then, in a low-oxygen atmosphere with an oxygen concentration of 0.1% or less, the coating film F3 of the SiC film material is irradiated with ultraviolet light. Specifically, in a low-oxygen atmosphere with an oxygen concentration of 0.1%, the entire upper surface of the coating film F3 of the SiC film material is irradiated with a predetermined dose of ultraviolet light. The reason for irradiating ultraviolet light in a low-oxygen atmosphere is that, in the absence of a low oxygen concentration, ozone is generated by ultraviolet light irradiation, and this ozone breaks the Si-C bond of the polycarbosilane. During the series of heating and ultraviolet light irradiation processes described above, a dehydration condensation reaction between polycarbosilanes in the SiC film material progresses, and finally, as shown in Figure 11 (C), a SiC film F4 is formed on the SoC film F2. The SiC film F4 has a thickness of, for example, 5 to 30 nm and a carbon content of 30 to 70%.

[0061] (Step S3) Thereafter, as shown in FIG. 11(D), a chemically amplified resist film F5 for EUV is formed directly on the SiC film formed on the wafer W.

[0062] Specifically, the wafer W is transported to the resist coating unit 33, and a chemically amplified resist liquid for EUV is spin-coated onto the surface of the wafer W, forming a coating film of the chemically amplified resist liquid for EUV so as to cover the SiC film F4. Next, the wafer W is transferred to the heat treatment unit 40 and pre-baked, and a chemically amplified resist film F5 for EUV is formed. The formed resist film F5 has a thickness of 30 to 100 nm.

[0063] By steps S1 to S3, the SoC film F2, the SiC film F4, and the resist film F5 are formed on the wafer W in this order from the bottom up (that is, without any other films being present between the films).

[0064] (Step S4) Next, the resist film F5 formed on the wafer W is exposed to light.

[0065] Specifically, the wafer W is transported to the exposure device 12 via the interface station 13, and an exposure process is performed using a mask M, as shown in FIG. 11(E), and the resist film on the wafer W is exposed to a desired pattern.

[0066] (Step S5) Then, the exposed resist film F5 formed on the wafer W is developed to form a resist pattern F6, as shown in FIG. 11(F).

[0067] Specifically, after exposure, the wafer W is transferred to the thermal processing unit 40 and subjected to post-exposure baking processing. Next, the wafer W is transferred to the development processing unit 30, where development processing is performed, and a resist pattern F6 is formed. After the pattern formation, the wafer W is transferred to the heat treatment unit 40, where post-baking processing is performed. Thereafter, the wafers W are sequentially accommodated in a cassette C and transported to the etching processing device 3.

[0068] (Step S6) Thereafter, dry etching is performed in the etching processing device 3.

[0069] Specifically, the SiC film F4 is dry-etched (first dry etching) using the resist pattern F6 as a mask. Next, the SiC film F4 to which the pattern has been transferred by the first dry etching is used as a mask to perform dry etching (second dry etching) on ​​the SoC film F2. Then, the SiO 2 The film F1 is subjected to dry etching (third dry etching). The first to third dry etchings are performed in different processing chambers.

[0070] With the above, the wafer processing using the wafer processing system 1 is completed.

[0071] <Effects> As described above, in this embodiment, a SiC film and an EUV chemically amplified resist film are formed in this order from below on an SoC film formed on a wafer W. In other words, in this embodiment, a SiC film is formed on an SoC film formed on a wafer W, and an EUV chemically amplified resist film is formed on the SiC film. Like the SoC film, the SiC film contains C atoms, but the C content is lower than that of the SoC film. The SiC film contains both Si atoms and C atoms, and the main structural portion of the SiC film is an aggregate P of portions m in which Si atoms are bonded via C atoms. More specifically, in the SiC film, the C atoms form carbosilane bonds (Si-C bonds). Therefore, the atomic arrangement structures of the SiC film and the SoC film are completely different, and the two are different substances. Therefore, the SiC film has a high etching selectivity relative to the SoC film. The etching selectivity of the SiC film relative to the SoC film is higher than that of the SO 2 The etching selectivity of the film is equal to or greater than that of SO 2 The etching selectivity of the resist pattern to the SiC film is higher than that of the SiC film. Also, for the same reason as above, the etching selectivity of the resist pattern to the SiC film is higher. Furthermore, the SiC film has high adhesion to the resist pattern, the reason for which will be described later. Therefore, a resist pattern formed by a chemically amplified resist film for EUV can be appropriately transferred to the SoC film. In this embodiment, the only film formed on the SoC film before the formation of the EUV resist film is the SiC film. 2 Compared with the case where the film is formed in the order of the membrane and the adhesion layer, this embodiment can achieve a higher throughput. That is, according to this embodiment, a resist pattern made of an EUV resist film can be appropriately transferred to an SoC film with high throughput.

[0072] In addition, in this embodiment, a SiC film is formed in the coating and developing apparatus 2, and then a chemically amplified resist film for EUV is formed. That is, in this embodiment, the time from the formation of the SiC film to the formation of the resist film is short. Therefore, it is possible to suppress the alteration of the SiC film before the formation of the resist film.

[0073] <Reasons for high adhesion of SiC film to resist pattern> The energy required for the resist pattern to fall when the developer is supplied to the surface of the resist pattern can be calculated as the adhesion work. The adhesion work can be expressed by the following mathematical formula. Adhesion work = γLR + γSL - γSR γLR: Difference in surface free energy between the developer and the resist film γSL: Difference in surface free energy between the developer and the underlayer film for the resist film formed on the wafer W γSR: Difference in surface free energy between the underlayer film and the resist film for the resist film formed on the wafer W

[0074] To prevent the resist pattern from falling, it is desirable to increase the adhesion work. Therefore, it is preferable that γSL is large and γSR is small. In this regard, as a result of intensive experiments and the like by the present inventors, in the case of a chemically amplified resist material for EUV lithography, when a carbon-based film is used as the underlayer film, it is possible to bring the surface free energy of the underlayer film closer to that of the resist material, that is, it is confirmed that γSR can be made small. In addition, it is also confirmed that a carbon-based film can secure a certain difference in surface free energy from the developer, that is, γSL can be made somewhat large.

[0075] And since the SiC film is a carbon-based film, γSL is large and γSR is small, so the adhesion work can be increased. Therefore, the SiC film can suppress the occurrence of falling of the resist pattern, in other words, the adhesion of the resist pattern is high.

[0076] <Evaluation test> 12 and 13 are diagrams showing an example of the results of evaluation of the collapse of a resist pattern when a SiC film is formed by the method according to the present embodiment. FIG. 12 and FIG. 13 show an example of a process window in which the exposure dose and the focus amount are changed when a pattern of a chemically amplified EUV resist film is formed at a predetermined height on a target substrate. FIG. 12 shows a case where a film formed between the SoC film and the EUV resist film of the target substrate, that is, an undercoat film, is a silicon-containing anti-reflective film (SiARC film), and FIG. 13 shows a case where the undercoat film is a SiC film. When forming a SiC film as the undercoat film, the oxygen concentration during ultraviolet irradiation of the coating film of the SiC film material was set to 400 ppm. The reason is as follows. That is, while the oxygen concentration during ultraviolet irradiation is preferably 0.1%, it was set to 400 ppm, which is about 1 / 2 of 0.1%, as a condition for increasing the reliability of processing on the entire surface by providing a sufficient margin on the oxygen concentration and not making the atmosphere stabilization time during low-oxygen processing too long. In addition, the formation, exposure, and development of the resist film were performed under the same conditions except for the type of film used as the base film for the EUV resist film, and the results were evaluated. Note that the thickness of the EUV resist film was set to 60 nm, about 20 nm thicker than the normally assumed thickness, in order to check the ease with which the pattern collapses. Also, the resist pattern was formed so that the pitch was about 20 nm.

[0077] Region R1 (region with white cells) shown in Figures 12 and 13 is a region where no damage was observed in the resist pattern. Region R2 is a region where pattern collapse was observed, and region R3 is a region where the pattern itself was crushed. As shown in Figures 12 and 13, when a SiARC film was formed, the pattern itself was crushed under the focus amount conditions of 0.08 μm and 0.12 μm, but when a SiC film was formed, collapse did not occur under a relatively wide range of exposure amount conditions. In this way, by forming a SiC film as the above-mentioned base film, it is possible to suppress collapse of the resist pattern.

[0078] In addition, during the above evaluation, the width of the pattern was also measured. According to the measurement results, the pattern became thinner as the exposure dose and the focus amount increased, and overall, the pattern tended to become more prone to collapse.

[0079] <Modification> Fig. 14 is a diagram showing the relationship between hole diameter and the number of shape defects of a pattern when a hole pattern is formed using a chemically amplified EUV resist film. Fig. 14 shows the above relationship when the ultraviolet light exposure dose during SiC film formation is 200 mJ and 500 mJ. As shown in the figure, the more UV light exposure during SiC film formation, the fewer the shape defects of the hole pattern, i.e., the higher the pattern adhesion. This tendency is particularly noticeable when the hole diameter is 24 μm or less.

[0080] 14, it can be seen that it is possible to reduce shape defects in hole patterns by increasing the amount of exposure to ultraviolet light. The same is true for line patterns, although not shown. The amount of exposure to ultraviolet light depends on the intensity and duration of ultraviolet light irradiation. Changing the intensity of ultraviolet light irradiation requires waiting time until the intensity of ultraviolet light stabilizes, so it is preferable to change the amount of exposure to ultraviolet light by changing the duration of ultraviolet light irradiation rather than the intensity of ultraviolet light irradiation. However, if the duration of ultraviolet light irradiation is increased, the time required for the entire process will be extended.

[0081] Therefore, the control device 4 may determine the irradiation time of ultraviolet rays and change the exposure amount of ultraviolet rays based on the conditions related to the defect and the wafer W to be processed.

[0082] Specifically, for example, the control device 4 may estimate the number of defects when ultraviolet rays are irradiated for the currently set irradiation time from the following correlation data stored in a storage unit (not shown), and if the estimated number of defects is greater than the target number of defects, it may determine to lengthen the irradiation time. The correlation data in this case is data indicating the correlation between the number of defects and processing conditions related to the wafer W to be processed, such as the target line width or hole diameter, the target film thickness, and the pattern type, when the currently set irradiation time is applied. The control device 4 may also estimate the pass / fail result of the product inspection when ultraviolet light is irradiated for the currently set irradiation time from the following correlation data stored in a storage unit (not shown), and if the estimated result is no, determine to extend the irradiation time. The correlation data in this case is data indicating the correlation between the above-mentioned processing conditions and the accumulated results of pass / fail of the product inspection when the currently set irradiation time is applied.

[0083] By determining the ultraviolet irradiation time as described above, it is possible to suppress defects while preventing an increase in the time required for the entire processing of the wafer W. This method is useful in the case of pattern dimensions in which the ultraviolet exposure amount has a large effect on the number of defects (for example, when the hole diameter is 24 μm or less).

[0084] In the above example, it is assumed that a film to be etched is formed in advance on the wafer W to be processed in the coating and developing treatment device 2. However, in the coating and developing treatment device 2, the film to be etched (e.g., spin-on SiO 2 A film) may be formed on the wafer W. In the above example, the SoC film is formed on the wafer W in the coating and developing treatment device 2. However, the SoC film may be formed on the wafer W outside the coating and developing treatment device 2.

[0085] In the above example, when forming the SiC film, the coating film of the SiC film material is heated and then irradiated with ultraviolet rays. However, heating may be performed after irradiation with ultraviolet rays. In the above example, the heating of the coating film of the SiC film material and the irradiation of ultraviolet light to the coating film of the SiC film material are performed in separate units, but they may be performed in one unit. In this case, heating and ultraviolet light irradiation may be performed simultaneously. Alternatively, the SiC film may be formed by simply heating the coating film of the SiC film material, without irradiating the coating film with ultraviolet rays, to promote the above-mentioned dehydration condensation.

[0086] In the above example, the EUV resist film is a chemically amplified type, but in the case where ultraviolet light is irradiated during the formation of the SiC film, which is the undercoat film, the EUV resist film may be a resist film containing a metal oxide, i.e., a metal-containing resist film. In the case of a metal-containing resist film, the adhesion between the SiC film and the resist pattern can be increased by irradiating the SiC film with ultraviolet light. One of the reasons for this is considered to be the following. That is, when ultraviolet light is irradiated, hydroxyl groups (OH groups) are generated on the surface of the SiC film, and the affinity of the EUV metal-containing resist to the SiC film increases due to these OH groups, and the line width of the part of the resist pattern that contacts the SiC film, i.e., the lower part of the pattern, becomes wider. As a result, it is considered that the adhesion between the SiC film and the resist pattern is increased. Note that the lower part of the resist pattern may be narrower than the upper part due to the influence of the development process, and in this case, it is preferable that the line width of the lower part of the pattern becomes wider as described above.

[0087] The embodiments disclosed herein should be considered as illustrative and not restrictive in all respects. The above-described embodiments may be omitted, substituted, or modified in various forms without departing from the scope and spirit of the appended claims. [Explanation of symbols]

[0088] 2 Coating and developing equipment 32 SiC film coating unit 33 Resist Coating Unit 40 Heat Treatment Unit 41 Irradiation unit F2 SoC membrane F4 SiC film F5 resist film W wafer

Claims

1. forming a silicon carbide film on a carbon film formed on a substrate; a resist film containing a metal oxide is formed directly on the silicon carbide film in a step subsequent to the step of forming the silicon carbide film, and a main structural portion in the silicon carbide film having silicon atoms and carbon atoms is an aggregate of portions in which silicon atoms are bonded to each other via carbon atoms.

2. 2. The substrate processing method according to claim 1, wherein the main structural portion has a structure in which a plurality of portions in which the silicon atoms are bonded via carbon atoms are bonded by dehydration condensation.

3. 3. The substrate processing method according to claim 1, wherein the atoms bonded to silicon atoms in the main structure portion do not include oxygen atoms, except for atoms constituting siloxane bonds, and include carbon atoms.

4. The substrate processing method according to any one of claims 1 to 3, wherein the step of forming the silicon carbide film comprises forming a film made of a silicon carbide film material on the carbon film, and then irradiating the film made of the silicon carbide film material with ultraviolet light in a low-oxygen atmosphere having an oxygen concentration of 0.1% or less, thereby forming the silicon carbide film.

5. 5. The substrate processing method according to claim 4, further comprising the steps of: forming a film made of said silicon carbide film material on said carbon film; heating said substrate; and then irradiating said ultraviolet light in said low-oxygen atmosphere.

6. 6. The substrate processing method according to claim 4, wherein the silicon carbide film material contains only polycarbosilane as a material containing a portion in which a silicon atom and a carbon atom are bonded.

7. 7. The substrate processing method according to claim 4, further comprising the step of determining an irradiation time of ultraviolet light to the film made of said silicon carbide film material based on conditions related to the substrate to be processed.

8. A program running on a computer of a control unit that controls a substrate processing apparatus so as to cause the substrate processing apparatus to perform the substrate processing method according to any one of claims 1 to 7.

9. a silicon carbide film forming unit that forms a silicon carbide film on a carbon film formed on a substrate; the silicon carbide film is a silicon carbide film formed by the silicon carbide film forming unit, and a resist film containing a metal oxide is formed directly on the silicon carbide film after the silicon carbide film is formed, and a main structural portion in the silicon carbide film having silicon atoms and carbon atoms is an aggregate of portions in which silicon atoms are bonded via carbon atoms.

10. The substrate processing apparatus according to claim 9 , wherein the main structural portion has a structure in which a plurality of portions in which the silicon atoms are bonded via carbon atoms are bonded by dehydration condensation.

11. 11. The substrate processing apparatus according to claim 9, wherein the atoms bonded to silicon atoms in the main structure portion do not include oxygen atoms, except for atoms forming siloxane bonds, and include carbon atoms.

12. a coating unit for forming a film made of a silicon carbide film material on the carbon film; 12. The substrate processing apparatus according to claim 9, further comprising: an irradiation unit that irradiates a film made of said silicon carbide film material with ultraviolet light in a low-oxygen atmosphere having an oxygen concentration of 0.1% or less to form said silicon carbide film.

13. a heating unit that heats the substrate after the silicon carbide film material is formed on the carbon film; The substrate processing apparatus according to claim 12 , wherein the irradiation unit irradiates the film made of the silicon carbide film material with ultraviolet light in the low-oxygen atmosphere after heating by the heating unit.

14. The substrate processing apparatus according to claim 12 or 13, wherein the silicon carbide film material contains only polycarbosilane as a material containing a portion in which a silicon atom and a carbon atom are bonded.

15. The substrate processing apparatus according to claim 12, wherein a time for irradiating the film made of said silicon carbide film material with ultraviolet light is determined based on conditions related to the substrate to be processed.

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