JP6231450B2 - Substrate processing method, program, computer storage medium, and substrate processing system - Google Patents

Description

  The present invention relates to a substrate processing method, a program, a computer storage medium, and a substrate processing system for processing a substrate on which a resist film is formed.

  For example, in a photolithography process in a semiconductor device manufacturing process, for example, a resist coating process is performed on a surface of a semiconductor wafer (hereinafter referred to as “wafer”) to form a resist film by applying a resist solution onto the film to be processed. An exposure process for exposing a predetermined pattern, a heating process (post-exposure baking) for promoting a chemical reaction in the resist film after the exposure, a development process for developing the exposed resist film, and the like are sequentially performed on the wafer. A pattern is formed.

  Incidentally, in recent years, in order to further increase the integration of semiconductor devices, it is required to make the pattern of the film to be processed finer. For this reason, the miniaturization of the resist pattern is being promoted, and a resist (chemically amplified resist) containing, for example, a photoacid generator is used as a resist corresponding to the miniaturization. (Patent Document 1).

JP 2012-165000 A

  In the chemically amplified resist as described above, the acid is generated by photolysis of the photoacid generator at the location exposed by the exposure process. Then, by performing post-exposure baking (hereinafter referred to as “PEB treatment”) after exposure, the resist is deprotected by the acid generated in the exposed portion.

  However, the acid generated in the exposed portion not only causes a deprotection reaction by PEB treatment, but also diffuses to the unexposed portion by thermal energy. If the acid diffuses to the unexposed area, the unexposed area may not be completely removed due to the influence of the diffused acid during the development process, and the line width of the resist pattern formed after the development may not be a desired dimension. . In particular, in recent years when the resist pattern has been miniaturized, the dimensional change due to the acid in the unexposed portion cannot be ignored.

  In addition, if the wafer is exposed to a heated atmosphere for some reason after post-exposure baking and before development processing, the diffusion of acid in the unexposed area may further progress, leading to further deterioration in pattern dimensions. There is also.

  The present invention has been made in view of this point, and an object of the present invention is to appropriately perform development processing by deactivating acid in a resist before development processing and form a resist pattern with a desired size. .

To achieve the above object, the present invention provides a substrate processing method for processing a substrate, wherein a resist film forming step for forming a resist film on the substrate and an exposure step for exposing a pattern to the resist film on the substrate are performed. A PEB treatment step of heating the substrate after the exposure step and deprotecting the resist film with an acid in the resist film; and an alkaline gas or an alkali for the resist film on the substrate after the PEB treatment step Supplying at least one of the mists of the solution and deactivating the acid in the resist film; and supplying a developer to the substrate after the acid deactivation process, and developing the resist film It further includes a development processing step to be performed, and a modification processing step for modifying the resist film after the acid deactivation step and before the development processing step .

  According to the present invention, the acid in the resist film is deactivated by the acid deactivation process that is performed after the PEB treatment process and before the development treatment process. There is no acid that is. Therefore, a development process can be performed without being affected by an acid, thereby forming a resist pattern having a desired dimension. In addition, even if the wafer is exposed to a heated atmosphere after acid deactivation and before development processing, there is no acid already in the resist, which may cause deterioration in pattern dimensions due to the progress of acid diffusion. Absent.

  In the modification treatment, the resist film may be reacted with a silicon-containing compound to silylate the resist film.

  After the PEB treatment step and before the acid deactivation step, the resist film after the PEB treatment step is irradiated with ultraviolet rays having a wavelength of 193 nm or 248 nm to deactivate the photoacid generator in the resist film. You may further have an ultraviolet irradiation process.

  The resist film may be an EUV resist film.

  According to another aspect of the present invention, there is provided a program that operates on a computer of a control unit that controls the substrate processing apparatus so that the substrate processing method is executed by the substrate processing apparatus.

  According to another aspect of the present invention, a readable computer storage medium storing the program is provided.

Furthermore, the present invention according to another aspect is a substrate processing system for processing a substrate, wherein exposure is performed by a resist coating apparatus that coats a resist film on the substrate and an exposure apparatus provided outside the substrate processing system. A resist substrate by heating a broken substrate and deprotecting the resist film with an acid in the resist film, and supplying at least one of an alkaline gas or a mist of an alkaline solution to the resist film An acid deactivation treatment device for deactivating the acid in the substrate; a development treatment device for supplying a developer onto the substrate to develop the resist film; and an acid deactivation treatment for deactivating the acid in the resist film. And a modification processing apparatus for performing a modification process on the resist film before the development process .
According to another aspect, there is provided a substrate processing system for processing a substrate, wherein exposure is performed by a resist coating apparatus that applies a resist film on the substrate and an exposure apparatus provided outside the substrate processing system. A substrate is heated, and a PEB processing apparatus for deprotecting the resist film with an acid in the resist film, and at least one of an alkaline gas or an alkali solution mist is supplied to the resist film to An acid deactivation treatment device for deactivating the acid, a development treatment device for supplying a developer onto the substrate to develop the resist film, and after heating in the PEB treatment device, the acid deactivation Before the acid deactivation treatment for deactivating the acid in the resist film in the processing apparatus, the resist film is irradiated with ultraviolet rays having a wavelength of 193 nm or 248 nm in the resist film. Deactivate the photoacid generator, and having an ultraviolet irradiation apparatus, the substrate processing system can be proposed.

  According to the present invention, the resist in the resist can be formed with desired dimensions by appropriately performing the development process by deactivating the acid in the resist before the development process.

It is a top view which shows the outline of a structure of the substrate processing system concerning this Embodiment. It is a side view which shows the outline of a structure of the substrate processing system concerning this Embodiment. It is a side view which shows the outline of a structure of the substrate processing system concerning this Embodiment. It is a longitudinal cross-sectional view which shows the outline of a structure of an acid deactivation processing apparatus. It is the flowchart explaining the main processes of wafer processing. It is explanatory drawing of the longitudinal cross-section which shows the state which the acid generate | occur | produced in the exposure part of the resist film. It is explanatory drawing of the longitudinal cross-section which shows the state which the acid of the exposed part of the resist film diffused to the unexposed part by heat processing. It is explanatory drawing of the longitudinal cross-section which shows a mode that the resist pattern was formed on the wafer. It is explanatory drawing of the longitudinal cross-section which shows a mode that the exposure part of a resist film expand | swells by silylation. It is explanatory drawing of the longitudinal cross-section which shows the mode of the resist pattern formed by performing positive type development to the resist film after silylation. It is a side view which shows the outline of a structure of the substrate processing system concerning other embodiment.

  Embodiments of the present invention will be described below. FIG. 1 is an explanatory diagram showing an outline of the configuration of a substrate processing system 1 that performs the substrate processing method according to the present embodiment. 2 and 3 are side views showing an outline of the internal configuration of the substrate processing system 1. In the present embodiment, the substrate processing system 1 is a coating and developing processing system that performs a photolithography process on the wafer W. By performing a modification process on the wafer W after the PEB process and before the developing process. A case where the wafer W is exposed to a heating atmosphere will be described as an example.

  As shown in FIG. 1, the substrate processing system 1 includes a cassette station 10 in which a cassette C containing a plurality of wafers W is loaded and unloaded, and a processing station 11 having a plurality of various processing apparatuses for performing predetermined processing on the wafers W. And an interface station 13 that transfers the wafer W to and from the exposure apparatus 12 adjacent to the processing station 11 is integrally connected.

  The cassette station 10 is provided with a cassette mounting table 20. The cassette mounting table 20 is provided with a plurality of cassette mounting plates 21 on which the cassette C is mounted when the cassette C is carried into and out of the substrate processing system 1.

  As shown in FIG. 1, the cassette station 10 is provided with a wafer transfer device 23 that is movable on a transfer path 22 that extends in the X direction. The wafer transfer device 23 is also movable in the vertical direction and the vertical axis direction (θ direction), and includes a cassette C on each cassette mounting plate 21 and a delivery device for a third block G3 of the processing station 11 described later. The wafer W can be transferred between the two.

  The processing station 11 is provided with a plurality of, for example, four blocks G1, G2, G3, and G4 having various devices. For example, the first block G1 is provided on the front side of the processing station 11 (X direction negative direction side in FIG. 1), and the second block is provided on the back side of the processing station 11 (X direction positive direction side in FIG. 1). Block G2 is provided. A third block G3 is provided on the cassette station 10 side (Y direction negative direction side in FIG. 1) of the processing station 11, and the interface station 13 side (Y direction positive direction side in FIG. 1) of the processing station 11 is provided. Is provided with a fourth block G4.

  For example, in the first block G1, as shown in FIG. 2, a plurality of liquid processing apparatuses, for example, a development processing apparatus 30 that develops the wafer W, an antireflection film (hereinafter referred to as “lower antireflection”) under the resist film of the wafer W. A lower antireflection film forming device 31 for forming a film), a resist coating device 32 for applying a resist solution to the wafer W to form a resist film, and an antireflection film (hereinafter referred to as “upper reflection” on the resist film of the wafer W). An upper antireflection film forming device 33 for forming an “antireflection film” is arranged in this order from the bottom.

  The development processing device 30, the lower antireflection film forming device 31, the resist coating device 32, and the upper antireflection film forming device 33 of the first block G1 have a plurality of cups F that accommodate the wafer W during processing in the horizontal direction. A plurality of wafers W can be processed in parallel. In these liquid processing apparatuses, spin coating in which a predetermined coating liquid is applied on the wafer W in the cup F is performed. In spin coating, for example, a coating liquid is discharged onto the wafer W from a coating nozzle, and the wafer W is rotated to diffuse the coating liquid to the surface of the wafer W.

  As shown in FIG. 3, the second block G2 includes a heat treatment apparatus 40 that heats and cools the wafer W, a hydrophobic treatment apparatus 41 that supplies the wafer W with a HMDS gas to perform a hydrophobic treatment, and a wafer W Peripheral exposure device 42 that exposes the outer peripheral portion, ultraviolet irradiation device 43 that irradiates the wafer W with ultraviolet rays, and acid in the resist film by supplying at least one of an alkaline gas or an alkali solution mist to the wafer W An acid deactivation processing device 44 for deactivating and a modification processing device 45 for modifying the resist film are provided side by side in the vertical direction and the horizontal direction. In addition, the number and arrangement | positioning of each apparatus 40-45 can be selected arbitrarily. The configuration of the acid deactivation processing device 44 will be described later. In the present embodiment, a case where the modification process performed by the modification processing apparatus 45 is silylation of a resist film will be described as an example.

  For example, in the third block G3, a plurality of delivery devices 50, 51, 52, 53, 54, 55, and 56 are provided in order from the bottom. The fourth block G4 is provided with a plurality of delivery devices 60, 61, 62 in order from the bottom.

  As shown in FIG. 1, a wafer transfer region D is formed in a region surrounded by the first block G1 to the fourth block G4. In the wafer transfer region D, for example, a plurality of wafer transfer devices 70 having transfer arms that are movable in the Y direction, the X direction, the θ direction, and the vertical direction are arranged. The wafer transfer device 70 moves in the wafer transfer area D and transfers the wafer W to a predetermined device in the surrounding first block G1, second block G2, third block G3, and fourth block G4. it can.

  Further, in the wafer transfer region D, a shuttle transfer device 80 that transfers the wafer W linearly between the third block G3 and the fourth block G4 is provided. The shuttle transfer device 80 is linearly movable, for example, in the Y direction in FIG. 3, and transfers the wafer W between the transfer device 52 of the third block G3 and the transfer device 62 of the fourth block G4. it can.

  As shown in FIG. 1, a wafer transfer apparatus 100 is provided next to the third block G3 on the positive side in the X direction. The wafer transfer apparatus 100 has a transfer arm that is movable in the X direction, the θ direction, and the vertical direction, for example. The wafer transfer device 100 can move up and down while supporting the wafer W, and can transfer the wafer W to each delivery device in the third block G3.

  The interface station 13 is provided with a wafer transfer device 110 and a delivery device 111. The wafer transfer device 110 has a transfer arm that is movable in the Y direction, the θ direction, and the vertical direction, for example. The wafer transfer device 110 can transfer the wafer W between each transfer device, the transfer device 111, and the exposure device 12 in the fourth block G4, for example, by supporting the wafer W on a transfer arm.

  Next, the structure of the acid deactivation processing apparatus 44 mentioned above is demonstrated. FIG. 4 is a longitudinal sectional view showing an outline of the configuration of the acid deactivation processing apparatus 44.

  The acid deactivation processing apparatus 44 has a bottomed, substantially U-shaped processing container 120 whose top is open, and a lid 121 that covers the opening of the processing container 120. A mounting table 122 on which the wafer W is mounted is provided on the upper bottom of the processing container 120. A heater 123 for heating the wafer W is provided inside the mounting table 112.

  The lid body 121 includes a horizontal top plate 130 and a side plate 131 that extends vertically downward from the outer peripheral edge of the top plate 130. A lower end portion 131 a of the side plate 131 faces the upper end portion 120 a of the processing container 120. Thereby, a processing space S is formed between the processing container 120 and the lid 121.

  The lid 121 includes an elevating mechanism 124 that moves the lid 121 up and down relatively with respect to the processing container 120. The lifting mechanism 124 may be provided on the processing container 120 side as long as the lid 121 and the processing container 120 can be moved up and down relative to each other. Further, the elevation mechanism 124 positions the lid 121 in the height direction with respect to the processing container 120 so that a predetermined gap G is formed between the lower end 131a of the side plate 131 and the upper end 120a of the processing container 120. Has been adjusted. In the present embodiment, the predetermined gap G is set to about 3 mm to 10 mm, for example.

  A gas supply unit 132 that supplies a processing gas to the wafer W from above the wafer W is provided at the center of the lower surface of the lid 121. As shown in FIG. 4, the gas supply unit 132 has a substantially truncated cone shape in which the vertical cross-sectional shape is formed in a trapezoidal shape having a narrow bottom bottom side. A gas flow path 133 formed in the lid 121 communicates with the gas supply unit 132.

  As shown in FIG. 4, a gas supply pipe 135 is connected to the gas flow path 133. At the opposite end of the gas flow path 133 in the gas supply pipe 135, an HMDS gas supply source 140 that supplies HMDS gas as an alkaline gas and a nitrogen gas supply source 141 that supplies, for example, nitrogen gas as a purge gas, respectively. It is connected. Valve bodies 142 and 143 having an opening / closing function and a flow rate adjusting function are provided on the gas flow path 133 on the downstream side of the HMDS gas supply source 140 and on the downstream side of the nitrogen gas supply source 141, respectively. As a result, the gas supplied to the wafer W can be switched alternately between the HMDS gas and the nitrogen gas. The gas supply unit 132 may supply an alkaline solution mist instead of the alkaline gas. In the present embodiment, for example, HMDS mist may be supplied instead of the HMDS gas. In addition, as the alkaline gas, any one of vaporized liquid phase at normal temperature such as the HMDS gas of the present embodiment, or one in gaseous phase such as ammonia gas may be used.

  A central exhaust part 150 is formed on the lower surface of the lid 121 and outside the gas supply part 132. The central exhaust unit 150 is configured by a plurality of exhaust holes 151 concentrically formed in the gas supply unit 132, for example, on the outside of the gas supply unit 132 at a position facing the central portion of the wafer W.

  A central exhaust passage 152 communicating with each exhaust hole 151 is formed inside the lid 121. A central exhaust pipe 153 is connected to the central exhaust path 152. The central exhaust pipe 153 is connected to an exhaust device 155 such as a vacuum pump via an exhaust mother pipe 154 provided in common to the central exhaust pipe 153 and an outer peripheral exhaust pipe 163 described later. Thereby, the atmosphere in the processing space S can be exhausted from the central exhaust part 150. The exhaust mother pipe 154 is provided with a valve body 156 having an opening / closing function.

  In addition, an outer peripheral exhaust portion 160 that exhausts the atmosphere in the processing space S from outside the wafer W on the mounting table 122 is formed at the lower end 131 a of the side plate 131 of the lid 121. The outer peripheral exhaust part 160 is configured by a plurality of exhaust holes 161 provided, for example, in a ring shape along the circumferential direction of the lower end part 131 a of the lid 121. Each exhaust hole 161 communicates with an outer peripheral exhaust passage 162 formed inside the lid 121.

  The outer peripheral exhaust passage 162 is connected to the exhaust mother pipe 154 via the outer peripheral exhaust pipe 163. The end of the outer exhaust pipe 163 on the exhaust main pipe 154 side is connected between a valve body 156 provided in the central exhaust pipe 153 and the exhaust device 155. The outer exhaust pipe 163 is provided with a flow restriction mechanism 164 that restricts the flow rate of the fluid flowing through the outer exhaust pipe 163. The flow restriction mechanism 164 is configured such that when the valve body 156 of the central exhaust pipe 153 is opened, the flow rate of the fluid flowing through the outer exhaust pipe 163 is the same as or less than the flow rate of the fluid flowing through the central exhaust pipe 153. ing. For example, an orifice or the like can be used as the flow restricting mechanism 164, but the flow restricting mechanism 164 only needs to have a function of restricting the flow rate as a minimum function. A valve element such as a needle valve having a function may be used instead of the orifice.

  Note that the hydrophobizing apparatus 41 has the same configuration as the acid deactivation apparatus 44. Further, in the modification processing apparatus 45 in the present embodiment, the gas supplied from the gas supply unit 132 is a low molecular compound containing silicon for silylation of the resist film, TMSDMA (N-trimethylsilyldimethylamine). Except for being gas, it has the same configuration as the acid deactivation processing apparatus 44.

  The substrate processing system 1 is provided with a control unit 200 as shown in FIG. The control unit 200 is a computer, for example, and has a program storage unit (not shown). The program storage unit stores a program for controlling the processing of the wafer W in the substrate processing system 1. The program storage unit also stores a program for controlling the operation of drive systems such as the above-described various apparatuses and transport apparatuses to realize the coating and developing process in the substrate processing system 1. The program is recorded on a computer-readable storage medium H such as a computer-readable hard disk (HD), a flexible disk (FD), a compact disk (CD), a magnetic optical desk (MO), or a memory card. May have been installed in the control unit 200 from the storage medium H.

  Next, wafer processing performed using the substrate processing system 1 configured as described above will be described. FIG. 5 is a flowchart showing an example of main steps of such wafer processing. In the present embodiment, the modification process performed in the modification apparatus 45 is silylation of the resist film as described above.

  First, a cassette C storing a plurality of wafers W is carried into the cassette station 10 of the substrate processing system 1, and each wafer W in the cassette C is sequentially transferred to the transfer device 53 of the processing station 11 by the wafer transfer device 23. .

  Next, the wafer W is transferred to the heat treatment apparatus 40 of the second block G2 by the wafer transfer apparatus 70 and subjected to temperature adjustment processing. Thereafter, the wafer W is transferred by the wafer transfer device 71 to, for example, the lower antireflection film forming device 31 of the first block G1, and a lower antireflection film is formed on the wafer W. Thereafter, the wafer W is transferred to the heat treatment apparatus 40 of the second block G2, and heat treatment is performed.

  Thereafter, the wafer W is transferred by the wafer transfer apparatus 70 to the hydrophobic treatment apparatus 41 of the second block G2. In the hydrophobic treatment apparatus 41, HMDS gas is supplied in a state where the wafer W is heated at, for example, about 90 ° C., and the hydrophobic treatment is performed. Next, the wafer W is transferred to the resist coating device 32 of the first block G1 by the wafer transfer device 70, and a resist film is formed on the wafer W (step S1 in FIG. 5). Thereafter, the wafer W is transferred to the heat treatment apparatus 40 and pre-baked. In this embodiment, for example, a negative EUV resist is used as the resist.

  Next, the wafer W is transferred to the upper antireflection film forming apparatus 33 of the first block G1, and an upper antireflection film is formed on the wafer W. Thereafter, the wafer W is transferred to the heat treatment apparatus 40 of the second block G2, and heat treatment is performed.

  Next, the wafer W is transferred to the upper antireflection film forming apparatus 33 by the wafer transfer apparatus 70, and an upper antireflection film is formed on the wafer W. Thereafter, the wafer W is transferred to the heat treatment apparatus 40 by the wafer transfer apparatus 70, heated, and temperature-adjusted. Thereafter, the wafer W is transferred to the peripheral exposure device 42 and subjected to peripheral exposure processing.

  Thereafter, the wafer W is transferred to the exposure apparatus 12 and subjected to exposure processing with a predetermined pattern (step S2 in FIG. 5).

  Next, the wafer W is transferred to the heat treatment apparatus 40 by the wafer transfer apparatus 70, and heated at, for example, about 95 ° C. and subjected to PEB processing (step S3 in FIG. 5). Thereby, for example, as shown in FIG. 6, the exposed portion 301 of the resist film 300 is deprotected by the acid 302 generated in the exposed portion 301 of the resist film 300. In the present embodiment, the heat treatment apparatus 40 functions as the PEB processing apparatus of the present invention. Thereafter, the wafer W is transferred to the acid deactivation processing apparatus 44 by the wafer transfer apparatus 70.

  In the acid deactivation processing apparatus 44, first, the wafer W is mounted on the mounting table 122 in a state where the lid 121 is raised to a predetermined position by the lifting mechanism 124.

  Next, the lid 121 is lowered to a position where a predetermined gap G is formed between the lower end 131 a of the lid 121 and the upper end 120 a of the processing container 120, thereby forming the processing space S.

  Next, the wafer W is heated by the heater 123 to a temperature lower than the temperature of the PEB process, in this embodiment, for example, 50 ° C., and then the valve body 142 is opened at a predetermined opening degree. Approximately 1% of HMDS gas is supplied into the processing space S at a predetermined flow rate. Further, the exhaust device 155 is activated together with the supply of the HMDS gas, and the HMDS gas is exhausted from the outer peripheral exhaust unit 160 at a predetermined flow rate. At this time, the valve body 156 of the exhaust mother pipe 154 is closed, and the exhaust in the processing space S is performed only from the outer peripheral exhaust part 160. As a result, the HMDS gas supplied from above the center of the wafer W flows so as to diffuse uniformly over the wafer W toward the outer peripheral edge of the wafer W. As a result, the HMDS gas penetrates into the resist film 300 on the wafer W, and the acid 302 generated in the exposure unit 301 is neutralized and deactivated (step S4 in FIG. 5).

  After supplying the HMDS gas for a predetermined time to deactivate the acid 302 in the resist film 300, the valve body 142 is closed and the supply of the HMDS gas is stopped. Then, the valve body 143 is opened at a predetermined opening, nitrogen gas is supplied from the gas supply unit 132 at a predetermined flow rate, and the HMDS gas remaining in the processing space S is purged for 10 seconds, for example. Further, the valve body 156 is opened together with the supply of the nitrogen gas, and the processing space S is exhausted from the central exhaust unit 150. Thereby, the HMDS gas in the processing container 120 is purged.

  After the purging in the processing container 120 is completed, the valve bodies 143 and 156 are closed and the exhaust device 155 is stopped. Next, the lid is raised to a predetermined height by the elevating mechanism 124, and the wafer W that has been subjected to the acid deactivation process is carried out of the processing container 120.

  Thereafter, the wafer W is transferred to the modification processing apparatus 45 by the wafer transfer apparatus 70. In the modification processing apparatus 45, the silylation of the resist film 300 is performed. In the modification processing apparatus 45, the TMSDMA gas is supplied to the resist film 300 after the wafer W is heated at a temperature equal to or higher than the silylation temperature and equal to or lower than the melting temperature of the resist film 300, for example, 130 ° C. in this embodiment. Thereby, a silanol group is added to the carboxyl group of the exposed portion 301, and the exposed portion 301 of the resist film 300 is silylated (step S5 in FIG. 5). The procedure for supplying the TMSDMA gas in the reformer 45 is the same as the procedure for supplying the HMDS gas in the acid deactivation processor 44.

  Here, in the case where the acid in the resist film is not deactivated before the development process, in the resist film 300 after the PEB process, as shown in FIG. The unexposed portion 303 is diffused by energy. In addition, when the reforming process with heat treatment, for example, is performed in a state where the acid 302 is not deactivated as described above, the acid 302 is further diffused by the heat energy in the reforming process and is originally deprotected. The deprotection proceeds even in the unexposed portion 303 that should not be. In this respect, in this embodiment, since the acid 302 in the resist film 300 has already been deactivated by the acid deactivation processing device 44, the reforming processing device 45 is heated at a temperature equal to or higher than the PEB processing temperature. However, the acid 302 does not diffuse into the resist film 300 and the unexposed portion 303 is not deprotected. In other words, the deprotected region in the resist film 300 does not change after the PEB process.

  Thereafter, the wafer W is transferred to the development processing apparatus 30 by the wafer transfer apparatus 70, and, for example, butyl acetate is supplied onto the wafer W to perform a negative development process (step S6 in FIG. 5). 8, the unexposed portion 303 is removed to form a predetermined resist pattern 310. At this time, the acid 302 that is a variation factor of the line width of the resist pattern 310 does not exist in the resist film 300. The development process can be performed without being affected by the acid 302. Further, the acid 302 is deactivated immediately after the PEB process, so that the deprotected region in the resist film 300 changes after the acid deactivation process. Therefore, the resist pattern 310 having a desired line width can be formed even when the wafer W is subjected to a modification process such as silylation that is exposed to a heated atmosphere. Rukoto can.

  Further, since the exposed portion 301 is cured by the silylation of the exposed portion 301 and becomes less soluble in butyl acetate, the butyl acetate between the exposed portion 301 and the unexposed portion 303 at the time of negative development. The dissolution contrast with respect to is improved. As a result, the line edge roughness (LER) and in-plane uniformity (CDU) of the resist pattern 310 are improved, and the resist pattern 310 with higher accuracy can be obtained.

  After the development is completed, the wafer W is transferred to the heat treatment apparatus 40 by the wafer transfer apparatus 70 and subjected to a post-bake process. Thereafter, the wafer W is transferred to the delivery device 50 of the third block G3 by the wafer transfer device 70, and then transferred to the cassette C of the predetermined cassette mounting plate 21 by the wafer transfer device 23 of the cassette station 10. Thus, a series of photolithography steps is completed.

  According to the above embodiment, HMDS gas is supplied as an alkaline gas to the wafer W after the PEB processing (step S3 in FIG. 5) by the acid deactivation processing apparatus 44, and the acid 302 in the resist film 300 is neutralized. 5 (step S4 in FIG. 5), the acid 302, which is a variation factor of the line width of the resist pattern 310, does not exist at the time of the development process, so that the development is not affected by the acid 302. Processing can be performed. Therefore, the line width of the resist pattern 310 can be made desired. In addition, since the deprotected region in the resist film 300 does not change after the acid deactivation step, the desired line width can be obtained even if a heat treatment such as silylation is performed before the development processing. The resist pattern 310 can be obtained.

  Further, by performing silylation of the resist film 300 before development processing, the dissolution contrast of the exposed portion 301 and the unexposed portion 303 of the resist film 300 with respect to butyl acetate is improved, so that the line edge roughness (LER) of the resist pattern 310 is improved. In-plane uniformity (CDU) is improved, and a resist pattern 310 with higher accuracy can be obtained.

  Further, when the conventional resist pattern 310 is silylated, the resist pattern 310 is silylated after the resist pattern 310 is formed by a development process in order to prevent the acid 302 from diffusing due to the heat treatment associated with the silylation. It was. However, in that case, there is a problem that a so-called pattern collapse occurs in which the resist pattern 310 collapses due to a stress on the resist pattern 310 accompanying the heat treatment. In this regard, when silylation is performed on the resist film 300 before development processing as in the present embodiment, the exposed portion 301 is not yet exposed to the unexposed portion 303 that becomes the resist pattern 310 after development processing at the time of silylation. There is no space where the unexposed portion 303 collapses even when stresses associated with heat treatment or the like during silylation act. Therefore, the problem of pattern collapse, which has been a problem when performing silylation after development processing, can be solved.

  In the above embodiment, silylation is performed as a resist modification process after the PEB process and before the development process. However, the modification process is not necessarily performed, and after the acid deactivation process step. Even when the development process is performed immediately, the effect of the present invention that the line width of the resist pattern 310 can be made desired by performing the development process without being affected by the acid 302 can naturally be obtained. it can.

  In the above embodiment, the acid is deactivated after the PEB treatment, and the resist film 300 is developed by negative development after silylation of the resist film. However, positive development may be performed in the development treatment. As described above, when the exposure unit 301 is silylated, the exposure unit 301 is cured. At this time, for example, as shown in FIG. 9, the exposure unit 301 expands so as to push the unexposed unit 303. Therefore, as shown in FIG. 10, for example, the unexposed portion 303 remaining as the resist pattern 320 after the positive development is pressed by the exposed portion 301 so that the surface unevenness is leveled. As a result, it is possible to obtain the same effect as when a so-called smoothing process is performed on the resist pattern 320 after the development process. When performing positive development, for example, in the development processing in step S6 shown in FIG. 5, an alkaline solution such as TMAH (tetramethylammonium hydroxide) is supplied instead of butyl acetate.

  In the above embodiment, the case where a negative type EUV resist is used as the resist has been described as an example. However, a positive type EUV resist may be used as the resist. When using a positive type resist, a positive type mask is used in the exposure process, and, for example, TMAH, which is an alkaline solution, is used in the development process, as in the case of using a negative type EUV resist. is there. Note that negative development may be used for the positive resist in the same manner as in the case of using positive development for the negative resist described above.

  In the above embodiment, the acid deactivation processing apparatus 44 supplies the HMDS gas while the wafer W is heated at, for example, 50 ° C., but the heating temperature of the wafer W is limited to the contents of the present embodiment. For example, the present inventors have confirmed that the acid 302 in the resist film 300 can be deactivated even at about room temperature (23 ° C.). Therefore, the temperature of the wafer W in the acid deactivation processing apparatus 44 may be a temperature at which the acid 302 in the resist film 300 can be deactivated by the HMDS gas. On the other hand, from the viewpoint of the throughput of the wafer W processing, the neutralization of the acid is promoted as the temperature of the wafer W is higher. However, when heated to a temperature higher than that during the PEB processing, the diffusion of the acid 302 in the resist film 300, In addition, since the deprotection reaction associated therewith proceeds, the upper limit temperature of the wafer heating in the acid deactivation step is preferably a temperature that is, for example, about 30 ° C. lower than the PEB processing temperature.

  In the above embodiment, the silylation of the resist film 300 is performed by the modification processing apparatus 45. However, the content of the modification process is not limited to the content of the present embodiment, and the silylation is performed. In addition, for example, the resist pattern 320 may be infiltrated with a metal-containing liquid, and then the wafer W may be subjected to a heat treatment so that the resist pattern 320 is cured (hardened). Of course, a treatment without heat treatment may be performed.

  In the hardening of the resist pattern 320, after performing the above-described steps S1 to S4 to deactivate the acid 302 in the resist film 300, a liquid metal-containing liquid is supplied onto the resist film 300. As the metal-containing liquid, for example, a solution in which a metal is dissolved in alcohol is used, and as the alcohol, for example, IPA (isopropyl alcohol), ethanol, butanol, MIBC (methyl isobutyl carbinol), or the like is used. As the metal, for example, Zr (zirconium), Ti (titanium), W (tungsten) or the like is used. This metal has a minute diameter, for example, a nanoparticle having a diameter of 5 nm or less.

  When the metal-containing liquid is applied onto the resist film 300, the alcohol in the metal-containing liquid is targeted to the functional group having good affinity, such as an OH group in the exposed part 301 of the resist film 300, in the exposed part 301. enter in. As the alcohol enters the exposure unit 301, the metal also enters the exposure unit 301 using the alcohol as an entry path. Then, the metal binds to the OH group in the exposed portion 301 and infiltrates into the exposed portion 301. At this time, metal does not enter the unexposed portion 303, and metal is deposited on the surface of the unexposed portion 303. Thereafter, a cleaning liquid is supplied onto the wafer W to remove the metal deposited on the unexposed portion 303, and then the wafer W is heat-treated with the heat treatment apparatus 40. As a result, the exposed portion 301 is hardened, and then a development process (step S6) is performed to form a cured resist pattern 320 on the wafer W.

  Such metal-containing liquid and cleaning liquid are supplied by spin coating. Therefore, when hardening the resist pattern 320 with a metal-containing liquid after the acid deactivation step (step S4), for example, as shown in FIG. A coating treatment apparatus 400 may be provided as a liquid treatment apparatus that supplies a cleaning liquid.

  Note that in the modification process performed after the PEB process and before the development process, such as silylation, as described above, the acid 302 in the resist film 300 is already deactivated. However, the photoacid generator remains in the resist film 300 even after acid deactivation, and the photoacid generator is heated by heating. The acid 302 may be generated by decomposition.

  Therefore, after the PEB treatment, for example, an ultraviolet irradiation process for irradiating the resist film 300 with ultraviolet rays to deactivate the photoacid generator in the resist film 300 may be performed. In carrying out the ultraviolet irradiation process, for example, after the PEB treatment, the wafer W is transferred to the ultraviolet irradiation device 43 before the acid deactivation treatment. In the ultraviolet irradiation device 43, the wafer W is irradiated with, for example, ultraviolet rays having a wavelength of 193 nm or 248 nm. As a result, the photoacid generator in the resist film 300 is deactivated, and even when the wafer W is heated in the subsequent modification process, the acid 302 is generated from the photoacid generator, or the resist film is generated by the generated acid 302. 300 is not deprotected. Therefore, a stable reforming process can be performed. The wavelength of the ultraviolet rays to be irradiated is not limited to 193 nm or 248 nm, and other ultraviolet rays can be used as appropriate. However, in the case of ultraviolet rays having a wavelength shorter than 193 nm, for example, 172 nm, the energy is high. Since the bond of the protective group in the resist film 300 may be cut too much after that, the wavelength of the ultraviolet light is preferably 193 nm or more.

  In the above embodiment, the hydrophobization of the wafer W is performed by the hydrophobization processing apparatus 41 and the deactivation process of the acid 302 in the resist film 300 is performed by the acid deactivation processing apparatus 44. The apparatus 41 and the acid deactivation processing apparatus 44 have the same configuration, and only the heating temperature of the wafer W during the hydrophobization process is different from the heating temperature of the wafer W during the acid deactivation process. Therefore, the substrate processing system 1 is provided with at least one of the hydrophobic treatment device 41 and the acid deactivation treatment device 44, and setting of the heater 123 that heats the wafer W during the hydrophobic treatment and the acid deactivation treatment. You may make it change and use temperature.

  The preferred embodiments of the present invention have been described above with reference to the accompanying drawings, but the present invention is not limited to such examples. It is obvious for those skilled in the art that various modifications or modifications can be conceived within the scope of the idea described in the claims, and these naturally belong to the technical scope of the present invention. It is understood. The present invention is not limited to this example and can take various forms. The present invention can also be applied to a case where the substrate is another substrate such as an FPD (flat panel display) other than a wafer or a mask reticle for a photomask.

  The present invention is useful when forming a resist pattern on a substrate.

DESCRIPTION OF SYMBOLS 1 Substrate processing system 30 Development processing apparatus 31 Lower antireflection film forming apparatus 32 Resist coating apparatus 33 Upper antireflection film forming apparatus 40 Heat treatment apparatus 41 Hydrophobic processing apparatus 42 Peripheral exposure apparatus 43 Ultraviolet irradiation apparatus 44 Acid deactivation processing apparatus 45 Modification Quality processing apparatus 300 Resist film 301 Exposed part 302 Acid 303 Unexposed part 310 Resist pattern 320 Resist pattern W Wafer

Claims (8)

A substrate processing method for processing a substrate, comprising:
A resist film forming step of forming a resist film on the substrate;
An exposure process for exposing the pattern to the resist film on the substrate;
A PEB treatment step of heating the substrate after the exposure step and deprotecting the resist film with an acid in the resist film;
An acid deactivation step of deactivating the acid in the resist film by supplying at least one of an alkaline gas or an alkali solution mist to the resist film on the substrate after the PEB treatment step;
A development processing step of supplying a developer to the substrate after the acid deactivation step and performing a development processing of the resist film, and
A substrate processing method, further comprising a modification treatment step of modifying the resist film after the acid deactivation step and before the development treatment step . 2. The substrate processing method according to claim 1 , wherein, in the modification treatment, the resist film is reacted with a silicon-containing compound to silylate the resist film. A substrate processing method for processing a substrate, comprising:
A resist film forming step of forming a resist film on the substrate;
An exposure process for exposing the pattern to the resist film on the substrate;
A PEB treatment step of heating the substrate after the exposure step and deprotecting the resist film with an acid in the resist film;
An acid deactivation step of deactivating the acid in the resist film by supplying at least one of an alkaline gas or an alkali solution mist to the resist film on the substrate after the PEB treatment step;
A development processing step of supplying a developer to the substrate after the acid deactivation step and performing a development processing of the resist film, and
After the PEB treatment step and before the acid deactivation step, the resist film after the PEB treatment step is irradiated with ultraviolet rays having a wavelength of 193 nm or 248 nm to deactivate the photoacid generator in the resist film. The substrate processing method further comprising an ultraviolet irradiation step . The resist film is characterized by a film of an EUV resist, a substrate processing method according to any one of claims 1-3. A program that operates on a computer of a control unit that controls the substrate processing system so that the substrate processing method according to any one of claims 1 to 4 is executed by the substrate processing system. A readable computer storage medium storing the program according to claim 5 . A substrate processing system for processing a substrate,
A resist coating apparatus for coating a resist film on a substrate;
A PEB processing apparatus that heats a substrate exposed by an exposure apparatus provided outside the substrate processing system and deprotects the resist film with an acid in the resist film;
An acid deactivation treatment apparatus for deactivating the acid in the resist film by supplying at least one of an alkaline gas or a mist of an alkaline solution to the resist film;
A development processing apparatus for developing the resist film by supplying a developer onto the substrate;
A modification processing apparatus for performing a modification process on the resist film after the acid deactivation process for deactivating the acid in the resist film and before the development process;
A substrate processing system comprising: A substrate processing system for processing a substrate,
A resist coating apparatus for coating a resist film on a substrate;
A PEB processing apparatus that heats a substrate exposed by an exposure apparatus provided outside the substrate processing system and deprotects the resist film with an acid in the resist film;
An acid deactivation treatment apparatus for deactivating the acid in the resist film by supplying at least one of an alkaline gas or a mist of an alkaline solution to the resist film;
A development processing apparatus for developing the resist film by supplying a developer onto the substrate;
Ultraviolet rays having a wavelength of 193 nm or 248 nm with respect to the resist film after heating in the PEB processing apparatus and before acid deactivation treatment for deactivating the acid in the resist film in the acid deactivation processing apparatus An ultraviolet irradiation device that deactivates the photoacid generator in the resist film by irradiating
A substrate processing system comprising:

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