JPWO2017221683A1 - Substrate processing method, readable computer storage medium, and substrate processing system - Google Patents

Abstract

The substrate processing method is a substrate processing method in which a substrate is processed using a block copolymer containing a hydrophilic polymer and a hydrophobic polymer, and a prewetting liquid containing a solvent for the coating solution of the block copolymer is supplied to the substrate. A pre-wet liquid film forming step for forming a liquid film of the pre-wet liquid, and then a block copolymer coating liquid is supplied to the substrate, and the substrate is rotated to form a block copolymer thin film. And a copolymer thin film forming step. In the pre-wet liquid film forming step, the liquid film of the pre-wet liquid is formed in an annular shape concentric with the substrate.

Description

(Cross-reference of related applications)
This application claims priority based on Japanese Patent Application No. 2006-125967 for which it applied to Japan on June 24, 2016, and uses the content here.

  The present invention relates to a substrate processing method using a block copolymer comprising a hydrophilic (polar) polymer having hydrophilicity (polarity) and a hydrophobic (nonpolar) polymer having hydrophobicity (no polarity). The present invention relates to a readable computer storage medium and a substrate processing system.

  For example, in the manufacturing process of a semiconductor device, for example, a resist coating process for coating a resist solution on a semiconductor wafer (hereinafter referred to as “wafer”) to form a resist film, an exposure process for exposing a predetermined pattern on the resist film, A photolithography process for sequentially performing a development process for developing the exposed resist film is performed to form a predetermined resist pattern on the wafer. Then, using this resist pattern as a mask, an etching process is performed on the film to be processed on the wafer, and then a resist film removing process or the like is performed to form a predetermined pattern on the film to be processed.

  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, miniaturization of the resist pattern is promoted, and for example, the wavelength of exposure processing light in photolithography processing is being shortened. However, there are technical and cost limitations to shortening the wavelength of the exposure light source, and it is difficult to form a fine resist pattern on the order of several nanometers, for example, only by the method of advancing the wavelength of light. is there.

Therefore, a wafer processing method using a block copolymer composed of two types of block chains (polymers), hydrophilic and hydrophobic, has been proposed (Patent Document 1). In this method, first, a guide is formed on a wafer by using a resist pattern, for example. Thereafter, a block copolymer is applied onto the wafer, and the block copolymer is subjected to a heat treatment to be separated into a hydrophilic polymer and a hydrophobic polymer. Thereafter, the wafer is irradiated with ultraviolet rays to modify the polymer, and an organic solvent is supplied onto the wafer, whereby the hydrophilic polymer is selectively removed.
In addition, as a method of applying the block copolymer to the wafer, the block copolymer solution is supplied to the center of the surface of the rotating wafer and the block copolymer solution is diffused on the wafer by centrifugal force. A method of applying a coating solution of a block copolymer by a so-called spin coating method is used.

Japanese Unexamined Patent Publication No. 2013-232621

  By the way, since the block copolymer applied to the wafer is required to have a high quality, the coating solution for the block copolymer is extremely expensive. Therefore, the coating amount of the block copolymer coating solution is preferably small. However, if the coating amount is too small, it is difficult to spread the block copolymer coating solution to the edge of the wafer by the spin coating method. As a method for solving this problem, a method of applying a liquid for preserving liquid (pre-wet liquid) before applying the coating liquid of the block copolymer can be considered. Since the fluidity of the block copolymer coating liquid is improved by applying the pre-wet liquid, the coating liquid can be extended to the edge of the wafer even if the supply amount of the coating liquid is small.

  However, according to the present inventors, in the above-described method of applying the pre-wet liquid before application of the block copolymer application liquid, depending on the relationship between the solvent of the block copolymer application liquid and the pre-wet liquid, It was confirmed that the following problems occur. That is, when the prewetting liquid and the block copolymer coating liquid are discharged to the center of the wafer and the prewetting liquid is applied to the wafer by the spin coating method, the thickness of the block copolymer when the coating liquid is dried is as follows. It was confirmed that the thickness was locally reduced at the center of the wafer. In order to obtain a desired pattern of the film to be processed, the film thickness of the block copolymer needs to be uniform over the entire wafer, and the requirement for the uniformity of the film thickness of the block copolymer is resist, etc. Is very strict compared to

  The present invention has been made in view of such points, and even when the coating solution of the block copolymer is applied to a wafer by a spin coating method, even when the supply amount of the coating solution is reduced, it is uniform. The object is to obtain a block copolymer having a film thickness.

  In order to achieve the above object, one embodiment of the present invention is a substrate processing method for processing a substrate using a block copolymer containing a hydrophilic polymer and a hydrophobic polymer. A pre-wet liquid film forming step of supplying a pre-wet liquid containing a solvent of the coating liquid to the substrate and forming a liquid film of the pre-wet liquid; and after the pre-wet liquid film forming process, the block copolymer coating liquid A block copolymer thin film forming step in which the substrate is rotated to form a thin film of the block copolymer, and the pre-wet liquid film forming step includes: Including a concentric annular film forming step.

  According to the present invention, since the pre-wet liquid is supplied before the block copolymer coating liquid is supplied, the consumption of the block copolymer coating liquid can be suppressed. In addition, since the liquid film of the pre-wet liquid containing the solvent for the coating solution of the block copolymer is formed in an annular shape, it is possible to prevent the thin film of the block copolymer from being locally thinned at the center of the wafer, A block copolymer thin film having a uniform film thickness can be formed.

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

  According to still another aspect of the present invention, there is provided a substrate processing system for processing a substrate using a block copolymer containing a hydrophilic polymer and a hydrophobic polymer, wherein the block copolymer coating liquid is used. A block copolymer coating device for supplying and forming a thin film of the block copolymer, the block copolymer coating device applying a prewetting liquid containing a solvent of the block copolymer coating liquid to the substrate. A first nozzle for supplying and a second nozzle for supplying a coating solution of the block copolymer to the substrate, and supplying the prewetting liquid to the substrate from the first nozzle, An annular pre-wet liquid film concentric with the substrate is formed on the substrate, and the block copolymer coating liquid is formed from the second nozzle on the substrate after the pre-wet liquid film is formed. Supply Forming a thin film of the serial block copolymer.

  According to the present invention, when a coating solution of a block copolymer using a predetermined solvent is applied to a wafer by a spin coating method, even if the supply amount of the coating solution is reduced, a uniform film thickness can be obtained. A block copolymer can be obtained.

It is explanatory drawing of the plane which shows the outline of a structure of the substrate processing system concerning this Embodiment. It is explanatory drawing of the plane which shows the outline of a structure of a coating processing apparatus. It is explanatory drawing of the front which shows the outline of a structure of a coating processing apparatus. It is explanatory drawing of the back surface which shows the outline of a structure of a coating processing apparatus. It is explanatory drawing of the plane which shows the outline of a structure of an etching apparatus. It is a longitudinal cross-sectional view which shows the outline of a structure of a block copolymer coating apparatus. It is a cross-sectional view which shows the outline of a structure of a block copolymer coating apparatus. It is explanatory drawing which shows a mode that the coating film of a block copolymer is formed on a wafer with a block copolymer coating apparatus. It is explanatory drawing which shows typically the mode of the thin film of a block copolymer. It is explanatory drawing which shows the mode of the thin film of the block copolymer before drying in a wafer center part. It is the flowchart explaining the main processes of wafer processing. It is a flowchart explaining the block copolymer thin film formation process. It is a figure which shows the film thickness distribution of the block copolymer thin film of Example 1 and Comparative Example 1. It is a figure which shows the film thickness distribution of the block copolymer thin film of Example 2 and Comparative Example 2.

  Embodiments of the present invention will be described below. FIG. 1 is an explanatory diagram of a plane showing an outline of a configuration of a substrate processing system 1 that performs a substrate processing method according to the present embodiment. In the present specification and drawings, elements having substantially the same functional configuration are denoted by the same reference numerals, and redundant description is omitted.

  The substrate processing system 1 includes a coating processing apparatus 2 that performs liquid processing such as photolithography processing on a wafer as a substrate, and an etching processing apparatus 3 that performs etching processing on the wafer.

  FIG. 2 is an explanatory diagram of a plane of the coating treatment apparatus 2, and FIGS. 3 and 4 are a front view and a rear view, respectively, schematically showing the outline of the internal configuration of the substrate processing system 1. The coating processing apparatus 2 in the present embodiment performs liquid processing such as coating processing and development processing.

  As shown in FIG. 2, the coating processing apparatus 2 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 that perform 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. 2, 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. 2), and the second side is provided on the back side of the processing station 11 (X direction positive direction side in FIG. 2). Block G2 is provided. Further, a third block G3 is provided on the cassette station 10 side (Y direction negative direction side in FIG. 2) of the processing station 11, and the interface station 13 side (Y direction positive direction side in FIG. 2) of the processing station 11 is provided. Is provided with a fourth block G4.

  For example, the first block G1 includes a plurality of liquid processing apparatuses, for example, a developing apparatus 30 that develops a resist formed on the wafer W to form a resist pattern, as shown in FIG. A neutral layer forming device 31 for forming a neutral layer by applying a neutral agent to the substrate, a cleaning device 32 for cleaning the wafer W by applying an organic solvent on the wafer W after forming the neutral layer, and on the wafer W A block copolymer coating device 33 for coating the block copolymer is stacked in order from the bottom.

  For example, the developing device 30, the neutral layer forming device 31, the cleaning device 32, and the block copolymer coating device 33 are arranged side by side in the horizontal direction. The number and arrangement of these liquid processing apparatuses can be arbitrarily selected.

  In these liquid processing apparatuses, for example, spin coating for applying a predetermined coating liquid onto the wafer W 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. The configuration of these liquid processing apparatuses will be described later.

  In addition, the block copolymer contained in the coating liquid applied on the wafer W by the block copolymer coating device 33 is the first polymer (the first polymer and the second monomer are linearly polymerized). A polymer (copolymer) having a polymer of a first monomer) and a second polymer (polymer of a second monomer). As the first polymer, a hydrophilic polymer having hydrophilicity (polarity) is used, and as the second polymer, a hydrophobic polymer having hydrophobicity (nonpolarity) is used. In the present embodiment, for example, polymethyl methacrylate (PMMA) is used as the hydrophilic polymer, and for example, polystyrene (PS) is used as the hydrophobic polymer, that is, for example, polystyrene (PS) -polymethyl methacrylate (PMMA). A block copolymer (PS-b-PMMA) is used. The ratio of the molecular weight of the hydrophilic polymer in the block copolymer is about 20% to 40%, and the ratio of the molecular weight of the hydrophobic polymer in the block copolymer is about 80% to 60%. The block copolymer coating solution (hereinafter referred to as BCP coating solution) is a solution obtained by making a block copolymer of these hydrophilic polymer and hydrophobic polymer into a solution with a solvent. When PS-b-PMMA is used as the block copolymer, propylene glycol monomethyl ether acetate (PGMEA) can be used as the solvent.

In this embodiment, a single solvent is used as the solvent for the BCP coating solution. In the BCP coating solution, the ratio of the solute, that is, the block copolymer to the solvent is less than 10%.
Further, as will be described later, the block copolymer coating device 33 forms a liquid film of the pre-wet liquid on the wafer W, and then discharges the BCP coating liquid onto the wafer to form a block copolymer thin film. To do.

  Further, the neutral layer formed on the wafer W by the neutral layer forming apparatus 31 is a layer having an intermediate affinity for the hydrophilic polymer and the hydrophobic polymer, and includes the hydrophilic polymer and the hydrophobic polymer. A random copolymer, a graft copolymer, or an alternating copolymer is used. In the present embodiment, for example, a random copolymer (PS-r-PMMA), a graft copolymer (PS-g-PMMA), or an alternating copolymer of polymethyl methacrylate and polystyrene is used as the neutral layer. . In the following, the term “neutral” means having an intermediate affinity for the hydrophilic polymer and the hydrophobic polymer.

  For example, in the second block G2, as shown in FIG. 4, an ultraviolet irradiating device 40 for modifying the wafer W by irradiating it with ultraviolet rays, and a heat treating device 41, 42 for performing a heat treatment of the wafer W are arranged in the vertical and horizontal directions. Is provided. The ultraviolet irradiation device 40 includes a mounting table on which the wafer W is mounted, and an ultraviolet irradiation unit that irradiates the wafer W on the mounting table with ultraviolet rays.

  The heat treatment apparatuses 41 and 42 have a hot plate for placing and heating the wafer W and a cooling plate for placing and cooling the wafer W, and can perform both heat treatment and cooling treatment. The heat treatment apparatus 41 is used for heat treatment before and after forming the neutral layer. The heat treatment device 42 is a polymer separation device that performs heat treatment of the wafer W coated with the block copolymer by the block copolymer coating device 33 and phase-separates the block copolymer into a hydrophilic polymer and a hydrophobic polymer. Function. Although the number and arrangement of the ultraviolet irradiation device 40 and the heat treatment devices 41 and 42 can be arbitrarily selected, it is preferable to arrange the wafer W so that the transfer time of the wafer W in the processing station 11 is the shortest.

  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. 2, 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 transport device 80 is movable linearly in the Y direction, for example. The shuttle transfer device 80 moves in the Y direction while supporting the wafer W, and can transfer the wafer W between the transfer device 52 of the third block G3 and the transfer device 62 of the fourth block G4.

  As shown in FIG. 2, a wafer transfer device 90 is provided next to the third block G3 on the positive side in the X direction. The wafer transfer device 90 has a transfer arm that is movable in the X direction, the θ direction, and the vertical direction, for example. The wafer transfer device 90 moves 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 91 and a delivery device 92. The wafer transfer device 91 has a transfer arm that is movable in the Y direction, the θ direction, and the vertical direction, for example. For example, the wafer transfer device 91 can transfer the wafer W between each transfer device, the transfer device 92, and the exposure device 12 in the fourth block G4 by supporting the wafer W on the transfer arm.

  As shown in FIG. 5, the etching processing apparatus 3 performs an etching process on the wafer W, a cassette station 100 that carries the wafer W into and out of the etching processing apparatus 3, a common transport unit 101 that transports the wafer W, and the like. Etching devices 102 and 103 as polymer removing devices for selectively removing either hydrophilic polymer or hydrophobic polymer, and etching devices 104 and 105 for etching a film to be processed on the wafer W into a predetermined pattern. doing.

  The cassette station 100 has a transfer chamber 111 in which a wafer transfer mechanism 110 for transferring the wafer W is provided. The wafer transfer mechanism 110 has two transfer arms 110a and 110b that hold the wafer W substantially horizontally, and is configured to transfer the wafer W while holding the wafer W by either of the transfer arms 110a and 110b. . A cassette mounting table 112 on which a cassette C capable of accommodating a plurality of wafers W arranged side by side is mounted on the side of the transfer chamber 111. In the illustrated example, a plurality of, for example, three cassettes C can be mounted on the cassette mounting table 112.

  The transfer chamber 111 and the common transfer unit 101 are connected to each other via two load lock devices 113a and 113b that can be evacuated.

  The common transfer unit 101 includes, for example, a transfer chamber chamber 114 having a sealable structure formed so as to have a substantially polygonal shape (in the illustrated example, a hexagonal shape) when viewed from above. In the transfer chamber 114, a wafer transfer mechanism 115 that transfers the wafer W is provided. The wafer transfer mechanism 115 has two transfer arms 115a and 115b that hold the wafer W substantially horizontally, and is configured to transfer the wafer W while holding it by either of the transfer arms 115a and 115b. .

  Etching devices 102 to 105 and load lock devices 113 b and 113 a are arranged outside the transfer chamber chamber 114 so as to surround the periphery of the transfer chamber chamber 114. The etching devices 102 to 105 and the load lock devices 113b and 113a are arranged, for example, so as to be arranged in this order in the clockwise direction when viewed from above, and to face the six side surfaces of the transfer chamber 114, respectively. ing.

  As the etching apparatuses 102 to 105, for example, an RIE (Reactive Ion Etching) apparatus is used, for example. That is, in the etching apparatuses 102 to 105, dry etching for etching the hydrophobic polymer or the film to be processed is performed by a reactive gas (etching gas), ions, or radicals.

  The substrate processing system 1 is provided with a control unit 300 as shown in FIG. The control unit 300 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 driving systems such as the above-described various processing apparatuses and transfer apparatuses to realize wafer processing in the substrate processing system 1. The program is recorded on a computer-readable storage medium such as a computer-readable hard disk (HD), flexible disk (FD), compact disk (CD), magnetic optical desk (MO), or memory card. Or installed in the control unit 300 from the storage medium.

  Next, the configuration of the above-described block copolymer coating device 33 will be described. The block copolymer coating device 33 has a processing container 120 as shown in FIG. A loading / unloading port (not shown) for the wafer W is formed on the side surface of the processing container 120.

  In the processing container 120, a spin chuck 121 is provided as a substrate holding unit that holds the wafer W and rotates it around the vertical axis. The spin chuck 121 can be rotated at a predetermined speed by a chuck driving unit 122 such as a motor.

  Around the spin chuck 121, there is provided a cup 123 that receives and collects the liquid scattered or dropped from the wafer W. A lower surface of the cup 123 is connected to a discharge pipe 124 that discharges the collected liquid and an exhaust pipe 125 that exhausts the atmosphere in the cup 123.

  As shown in FIG. 7, a rail 126 extending along the Y direction (left and right direction in FIG. 7) is formed on the X direction negative direction (downward direction in FIG. 7) side of the cup 123. The rail 126 is formed, for example, from the outside of the cup 123 in the Y direction negative direction (left direction in FIG. 7) to the outside in the Y direction positive direction (right direction in FIG. 7). A nozzle arm 127 is attached to the rail 126.

  The nozzle arm 127 is movable on the rail 126 by a nozzle driving unit 128 shown in FIG. As a result, the nozzle arm 127 can move from the standby unit 129 installed on the outer side of the cup 123 on the positive side in the Y direction to above the center of the wafer W in the cup 123, and further on the surface of the wafer W It can move in the radial direction of W. The nozzle arm 127 can be moved up and down by the nozzle drive unit 128, and the height of the nozzle arm 127 can be adjusted.

  As shown in FIG. 6, the nozzle arm 127 is provided with a first nozzle 130 for supplying a pre-wet liquid and a second nozzle 131 for supplying a BCP coating liquid.

  The first nozzle 130 is connected to a pre-wet liquid supply unit 133 via, for example, a pipe 132. The pre-wet liquid supply unit 133 includes a pre-wet liquid supply source, a pump, a valve, and the like, and is configured to discharge the pre-wet liquid from the tip of the first nozzle 130. Similarly to the first nozzle 130, the second nozzle 131 is also connected to the BCP coating liquid supply unit 135 via the pipe 134, and can discharge the BCP coating liquid from the second nozzle 131. The pre-wet liquid in the present embodiment is a liquid having a good compatibility with the solvent of the BCP coating liquid, and includes, for example, a solvent having the same component as the solvent of the BCP coating liquid. More specifically, as described above, in this embodiment, a single solvent is used as the solvent of the BCP coating solution. However, when the block copolymer is PS-b-PMMA and the single solvent is PGMEA, As the pre-wet liquid, a mixed solution of PGMEA and propylene glycol monomethyl ether (PGME) (for example, the mixing ratio is 7: 3) can be used.

  Then, the coating method of the BCP coating liquid using the above-mentioned block copolymer coating apparatus 33 is demonstrated using FIGS. 8-10. FIG. 8 is a view for explaining pre-wet liquid and BCP coating liquid discharge positions in the block copolymer coating apparatus 33. 9 and 10 are schematic views showing the state of the film formed by the block copolymer coating device 33 at the center of the wafer.

  The prewetting liquid L1 is discharged from the first nozzle 130 of the block copolymer coating apparatus 33 at the center of the wafer W as shown in FIG. It is assumed that the wafer W is rotated while discharging L1, and the liquid film F1 of the pre-wet liquid L1 is formed on the entire surface of the wafer W as shown in FIG. Thereafter, while discharging the BCP coating liquid L2 from the second nozzle 131 of the block copolymer coating apparatus 33 to the center of the wafer W, the wafer W is rotated to form a block copolymer (coating liquid) thin film. When the thin film is dried, a block copolymer thin film F3 as shown in FIG. 9A is obtained. The thin film F3 in FIG. 9A is thin at the center C of the wafer W.

  According to the present inventors, as described above, the phenomenon that the thin film of the block copolymer after drying is locally thinned in the central portion was obtained by using a BCP coating solution containing a plurality of solvents instead of a single solvent. In some cases, when a pre-wet liquid having a poor compatibility with the single solvent is used for the BCP coating liquid of a single solvent, it is not observed.

As described above, the reason why the block copolymer thin film after drying is locally thinned in the central portion can be considered as follows.
That is, the pre-wet liquid has good compatibility with the solvent of the BCP coating liquid, and specifically includes a solvent having the same component as the solvent of the BCP coating liquid. Therefore, the pre-wet liquid has a high solubility of the block copolymer, similar to the solvent of the BCP coating liquid. When this pre-wet liquid discharge position is set at the center of the wafer, the centrifugal force does not act on the pre-wet liquid at the center of the wafer. Therefore, as shown in FIG. In the liquid film F5 of the BCP coating liquid (and the mixed liquid of the pre-wet liquid), the amount of the pre-wet liquid locally increases in the wafer center portion C as compared with other portions. That is, the ratio of the solvent (component) having a high solubility of the block copolymer is high in the wafer center C. Therefore, since the dissolution of the block copolymer is promoted in the wafer center portion C in the drying process as compared with other portions, the thickness of the block copolymer after drying in the wafer center portion C is locally reduced. It is considered a thing.

Therefore, in the present embodiment, the block copolymer coating device 33 first forms a liquid film of the pre-wet liquid in an annular shape concentric with the wafer W. Specifically, the discharge position of the pre-wet liquid L1 from the first nozzle 130 of the block copolymer coating apparatus 33 is arranged at a predetermined position on the outer peripheral portion of the wafer W as shown in FIG. In a state where the pre-wet liquid L1 is discharged from the first nozzle 130, the wafer W is rotated once to form an annular liquid film of the pre-wet liquid L1.
Thereafter, the wafer W is rotated, and the liquid film F2 of the pre-wet liquid L1 is spread to the outer periphery of the wafer W as shown in FIG. Then, the wafer W is rotated in a state where the BCP coating solution is discharged from the second nozzle 131 of the block copolymer coating device 33 to the center of the wafer W, thereby forming a thin film of the BCP coating solution. In this case, since the pre-wet liquid does not exist in the central portion, as shown in FIG. 10B, there is a portion where the proportion of the solvent having a high solubility of the block copolymer is locally large even in the central portion C of the wafer. do not do. Therefore, when the liquid film of the BCP coating solution is dried, a block copolymer thin film F4 having a uniform film thickness is obtained as shown in FIG. 9B.

  Next, wafer processing performed using the substrate processing system 1 will be described. FIG. 11 is a flowchart showing an example of main steps of such wafer processing.

  First, a cassette C storing a plurality of wafers W is carried into the cassette station 10 of the substrate processing system 1 and placed on a predetermined cassette placement plate 21. Thereafter, the wafers W in the cassette C are sequentially taken out by the wafer transfer device 23 and transferred to the transfer device 53 of the processing station 11. Note that a resist film is formed in advance on the wafer W to be processed by the substrate processing system 1, and the resist film is subjected to exposure processing in a predetermined pattern.

  Next, the wafer W is transferred to the developing device 30 by the wafer transfer device 70. In the developing device 30, a developing solution is supplied to the wafer W, and the resist is developed into a predetermined pattern. After the development is completed, the wafer W is transferred to the heat treatment apparatus 41 by the wafer transfer apparatus 70 and subjected to a post-bake process. In this way, a predetermined resist pattern is formed on the wafer W (step S1 in FIG. 11). In the present embodiment, the resist pattern is a so-called line-and-space resist pattern having a straight line portion and a straight space portion in plan view. The width of the space part is set so that hydrophilic polymer and hydrophobic polymer are alternately arranged in the odd number layer in the space part.

  Next, the wafer W is transferred to the neutral layer forming device 31 by the wafer transfer device 70. In the neutral layer forming apparatus 31, a neutral agent is applied on the wafer W to form a neutral layer (step S2 in FIG. 11). Thereafter, the wafer W is transferred to the heat treatment apparatus 41, heated, temperature-controlled, and then returned to the delivery apparatus 53.

  Thereafter, the wafer W is transferred to the cleaning device 32 by the wafer transfer device 70. In the cleaning device 32, an organic solvent is supplied onto the wafer W after the neutral layer is formed, and foreign matters on the resist pattern and the neutral layer are washed away.

  Thereafter, the wafer W is transferred to the block copolymer coating device 33 by the wafer transfer device 70. In the block copolymer coating device 33, a thin film of the block copolymer is formed on the neutral layer of the wafer W (step S3 in FIG. 11).

  FIG. 12 is a flowchart showing an example of a block copolymer thin film forming process in the block copolymer coating apparatus 33. It is assumed that the wafer W has a diameter of 300 mm.

  The wafer W carried into the block copolymer coating device 33 is first held by the spin chuck 121. Subsequently, the first nozzle 130 is moved up to a position 55 mm away from the center of the wafer W by the nozzle arm 127. Next, while discharging the pre-wet liquid from the first nozzle 130, the chuck driving unit 122 is controlled to rotate the wafer W at 10 rpm for 6 seconds. Thereby, an annular pre-wet liquid film concentric with the wafer W is formed on the wafer W (step S11 in FIG. 12).

  Thereafter, the discharge of the pre-wet liquid from the first nozzle 130 is stopped. The second nozzle 131 is moved by the nozzle arm 127 so as to be positioned above the center of the wafer. During this movement, the wafer W is rotated at a low speed of 30 rpm for 1 second, and then the wafer W is rotated at 1000 rpm for 0.1 second. Thereby, the liquid film of the pre-wet liquid can be spread to the outer peripheral portion of the wafer W (step S12 in FIG. 12, pre-wet liquid diffusion process). The rotation at 30 rpm for one second is performed so that the pre-wet liquid diffusion process is performed during the movement of the second nozzle 131, but the pre-wet liquid film does not spread toward the wafer center before the start of the diffusion process. It is to make it. Further, by spreading the pre-wet liquid film to the outer peripheral portion of the wafer W before the application of the BCP coating liquid, a dry patch (part where the BCP coating liquid is not supplied) is generated during the subsequent application of the BCP coating liquid. Can be prevented.

After the movement of the second nozzle 131 and the end of the pre-wet liquid diffusion process, the BCP coating liquid is supplied from the second nozzle 131 located above the center of the wafer, and the wafer W is rotated at 2500 rpm for 1 second. Thereafter, the wafer W is rotated at 100 rpm while the supply of the BCP coating solution is maintained in order to flatten the liquid film of the BCP coating solution. Then, after the supply of the BCP coating solution is stopped, the wafer W is rotated at 1500 rpm for 15 seconds. As a result, the BCP coating liquid is dried, and a block copolymer thin film having a desired and uniform thickness is formed on the wafer (step S13 in FIG. 12).
Here, “drying” does not mean that all the solvent in the block copolymer thin film (the solvent in the BCP coating solution and the pre-wet liquid) is volatilized, but the ratio of the solvent in the block copolymer thin film is the block copolymer. It means that the solvent in the block copolymer thin film is volatilized until it becomes suitable for phase separation of the polymer.

  The position of the first nozzle 130 for forming the annular pre-wet liquid film is not limited to the position above the position 55 mm away from the center of the wafer W, but the pre-wet discharged from the first nozzle 130. It is a position where the liquid does not spread to the center of the wafer and may be a position where a processing-saving liquid effect can be obtained. For example, in the case of a wafer W having a diameter of 300 mm, the horizontal distance from the center of the wafer W to the first nozzle 130 may be 5 to 60 mm. Further, in the case of a wafer W having a diameter of 450 mm, the horizontal distance from the center of the wafer W to the first nozzle 130 may be 7.5 to 90 mm. That is, the distance from the center of the wafer W to the first nozzle when discharging the pre-wet liquid is preferably larger than 3.3% of the radius of the wafer W and smaller than 40% of the radius.

Further, the film thickness of the block copolymer thin film formed by the block copolymer coating device 33 is preferably thinner considering the time required for phase separation of the block copolymer and the miniaturization of the pattern, for example, about 20 to Although it is 60 nm, the film thickness is not limited to this, and is 100 nm or less, preferably 80 nm or less.
The viscosity of the BCP coating solution is, for example, about 1 to 2 cP (centipoise), and is preferably 3 cP or less.

  In the block copolymer thin film forming step, after the block copolymer thin film is dried and the film thickness is adjusted in step S13, the outer periphery of the wafer W is washed with a rinse liquid using an EBR (Edge Bead Remover) nozzle. Also good. The cleaning may be performed on both the front and back surfaces of the wafer W, or may be performed on either one.

Returning to the description of FIG.
The wafer W on which the block copolymer thin film is formed is transferred to the heat treatment apparatus 42 by the wafer transfer apparatus 70. In the heat treatment apparatus 42, heat treatment at a predetermined temperature is performed on the wafer W. At this time, for example, nitrogen gas is supplied to make the inside of the heat treatment apparatus 42 into a low oxygen atmosphere, and the heat treatment is performed in the nitrogen gas atmosphere. Then, the block copolymer on the wafer W is phase-separated into a hydrophilic polymer and a hydrophobic polymer (step S4 in FIG. 11).

  Here, as described above, in the block copolymer, the ratio of the molecular weight of the hydrophilic polymer is 40% to 60%, and the ratio of the molecular weight of the hydrophobic polymer is 60% to 40%. Then, in step S4, the hydrophilic polymer and the hydrophobic polymer are phase-separated into a lamellar structure. Further, since the width of the space portion of the resist pattern is formed to a predetermined width, an odd number of hydrophilic polymers and hydrophobic polymers are alternately arranged in the space portion of the resist pattern.

  Thereafter, the wafer W is transferred to the delivery device 50 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.

  When a predetermined process is performed on the wafer W in the coating processing apparatus 2, the cassette C storing the wafer W is unloaded from the coating processing apparatus 2 and loaded into the etching processing apparatus 3.

  Next, the wafer W taken out from the cassette C is transferred to the etching apparatus 102. In the etching apparatus 102, the hydrophilic polymer is selectively removed by the etching process, and a predetermined pattern of the hydrophobic polymer is formed (step S5 in FIG. 11).

  Thereafter, the wafer W is accommodated in the cassette C and unloaded from the etching processing apparatus 3.

  According to the above embodiment, since the pre-wet liquid is applied before the BCP coating liquid is applied, the consumption amount of the BCP coating liquid can be suppressed. It does not occur. Further, by forming the liquid film of the pre-wet liquid in an annular shape concentric with the wafer W, the ratio of the solvent in the block copolymer thin film at the center of the wafer can be suppressed, so that the block film having a uniform film thickness can be obtained. A polymer thin film can be obtained.

In the above embodiment, the pre-wet liquid is applied in advance when the thin film of the block copolymer is formed, but the annular shape of the same pre-wet liquid is also formed when the neutral layer is formed. A pre-wet liquid may be applied in advance so that a liquid film is formed. When the compatibility of the solvent used for the coating liquid for forming the neutral layer and the pre-wetting liquid for the neutral layer is good, when the pre-wetting liquid for the neutral layer is discharged to the center of the wafer, the block copolymer thin film and Similarly, this is because the film thickness of the neutral layer at the center of the wafer is locally reduced.
For example, when a solution of PS-r-PMMA or PS-g-PMMA containing PGMEA as a single solvent is used as a neutral layer coating solution, a solution containing PGMEA as a neutral layer pre-wet solution may be used. it can. The method for supplying and diffusing the pre-wet liquid for the neutral layer and the method for forming the neutral layer using the coating liquid for the neutral layer after application of the pre-wet liquid are the same as those for the block copolymer described above. The method can be adopted.
The neutral layer may not be formed when an antireflection film is formed on the wafer W.

  In the above embodiment, the so-called dry etching process is performed in the etching processing apparatus 3 to selectively remove the hydrophilic polymer. However, the hydrophilic polymer may be removed by a wet etching process. In such a case, in step S5, the wafer is first transferred to the ultraviolet irradiation device 40 instead of the etching processing device 3. Then, by irradiating the wafer W with ultraviolet rays having a wavelength of 200 nm or less, for example, 172 nm, the bonding chain of polyethyl methacrylate, which is a hydrophilic polymer, is cut, and polystyrene, which is a hydrophobic polymer, is crosslinked. Thereafter, the wafer W is transferred to a solution supply device (not shown) provided in the coating processing apparatus 2 or the like, and for example, isopropyl alcohol is supplied to the wafer W in the solution supply device. Thereby, the hydrophilic polymer in which the bond chain is cleaved by ultraviolet irradiation is removed.

  Further, in the above embodiment, a resist film is formed in advance on the wafer W, and the resist film has been subjected to an exposure process in a predetermined pattern. Exposure processing using the exposure apparatus 12 may be performed.

In Examples 1 and 2, a block copolymer thin film was formed on a wafer having a flat surface on which a resist pattern or the like was not formed in accordance with the procedure described in the flowchart of FIG.
In Comparative Examples 1 and 2, in the procedure of Examples 1 and 2, only the prewetting condition was changed, and a thin film of a block copolymer was formed on a wafer on which no resist pattern was formed. In Examples 1 and 2, the pre-wet liquid was supplied from a position 55 mm away from the center of the wafer to form an annular shape, but in Comparative Examples 1 and 2, the rotation of the wafer was stopped, The pre-wet liquid was discharged for 2 seconds at the center of the wafer, and then the wafer was rotated at 1000 rpm for 0.1 second to spread the pre-wet liquid over the entire wafer.

  In Example 1 and Comparative Example 1, PME-842 manufactured by Merch was used as a coating solution for PS-b-PMMA using PGMEA as a single solvent. In Example 2 and Comparative Example 2, BP-D032C manufactured by Tokyo Ohka Kogyo Co., Ltd. was used as the coating solution. In Examples 1 and 2 and Comparative Examples 1 and 2, OK73 manufactured by Tokyo Ohka Kogyo Co., Ltd. (7: 3 mixed solution of PGMEA and PGME) was used as the prewetting liquid.

  FIG.12 and FIG.13 is a figure which shows distribution of the film thickness of the block copolymer in an Example and a comparative example. 12 and 13, the horizontal axis represents the distance from the wafer center, and the vertical axis represents the thickness. The film thickness was measured by the method of ~.

As is apparent from FIG. 12, in Comparative Example 1, the thickness of the block copolymer is locally thin at the center of the wafer.
On the other hand, in Example 1, as shown in FIG. 12, the film thickness of the block copolymer is uniform even at the center of the wafer.
In Comparative Example 1, the film thickness of the block copolymer is reduced from the wafer center to the outer periphery. In Example 1, the film thickness of the block copolymer is uniform over the entire wafer. Further, even if the supply amount of the BCP coating liquid is the same as described above, the chemical saving liquid can be expected because the film thickness of the outer peripheral portion of Example 1 is larger.
Comparative Example 2 and Example 2 are the same as Comparative Example 1 and Example 2. That is, the effect of the present invention can be obtained regardless of the type of BCP coating solution.

  In the above embodiment, the block copolymer on the wafer W is phase-separated into a hydrophilic polymer having a lamellar structure and a hydrophobic polymer. However, the substrate processing system 1 of the present invention converts the block copolymer into a hydrophilic structure having a cylinder structure. The present invention can also be applied to the case of phase separation into a conductive polymer and a hydrophobic polymer.

  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 changes or modifications can be conceived within the scope of the idea described in the claims, and these are naturally within 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 a substrate is treated with a block copolymer including, for example, a hydrophilic polymer having hydrophilicity and a hydrophobic polymer having hydrophobicity.

DESCRIPTION OF SYMBOLS 1 ... Substrate processing system 2 ... Coating processing apparatus 33 ... Block copolymer coating apparatus 120 ... Processing container 121 ... Spin chuck 122 ... Chuck drive part 123 ... Cup 124 ... Discharge pipe 125 ... Exhaust pipe 126 ... Rail 127 ... Nozzle arm 128 ... Nozzle driving unit 129 ... Standby unit 130 ... First nozzle 131 ... Second nozzle 133 ... Pre-wet liquid supply unit 135 ... BCP coating solution supply unit

Claims (17)

A substrate processing method for processing a substrate using a block copolymer containing a hydrophilic polymer and a hydrophobic polymer,
A pre-wet liquid film forming step of supplying a pre-wet liquid containing a solvent of the coating solution of the block copolymer to the substrate and forming a liquid film of the pre-wet liquid; and
After the pre-wet liquid film forming step, a block copolymer thin film forming step of supplying the block copolymer coating liquid to the substrate, rotating the substrate, and forming a thin film of the block copolymer; Have
The pre-wet liquid film forming step includes an annular film forming step of forming a liquid film of the pre-wet liquid in an annular shape concentric with the substrate. The substrate processing method according to claim 1,
In the annular film forming step, the nozzle for supplying the pre-wet liquid is disposed at a predetermined position on the outer peripheral portion of the substrate, and the substrate is rotated once while the pre-wet liquid is supplied from the nozzle, A liquid film of the pre-wet liquid is formed in the annular shape. The substrate processing method according to claim 2,
The distance from the center of the substrate to the nozzle is greater than 3.3% of the radius of the substrate and less than 40% of the radius. The substrate processing method according to claim 2,
In the pre-wet liquid film forming step, the substrate is rotated at a rotational speed faster than the rotational speed of the substrate in the annular film forming step, and the liquid film of the pre-wet liquid formed in the annular shape is arranged in the outer peripheral direction of the substrate. It includes a pre-wet liquid film diffusion step that spreads. The substrate processing method according to claim 1,
A drying step of drying the block copolymer thin film. The substrate processing method according to claim 1,
In the block copolymer thin film forming step, the block copolymer coating solution is supplied to the center of the substrate. The substrate processing method according to claim 1,
The thickness of the block copolymer thin film is 100 nm or less. The substrate processing method according to claim 1,
The viscosity of the coating solution of the block copolymer is 3 cP or less. A substrate processing method for processing a substrate using a block copolymer including a hydrophilic polymer and a hydrophobic polymer is executed on a computer of a control unit that controls the substrate processing system so that the substrate processing system executes the substrate processing method. A readable computer storage medium storing a program to be executed,
The substrate processing method includes:
A pre-wet liquid film forming step of supplying a pre-wet liquid containing a solvent of the coating solution of the block copolymer to the substrate and forming a liquid film of the pre-wet liquid; and
After the pre-wet liquid film forming step, a block copolymer thin film forming step of supplying the block copolymer coating liquid to the substrate, rotating the substrate, and forming a thin film of the block copolymer; Have
The pre-wet liquid film forming step is a readable computer storage medium including an annular film forming step of forming a liquid film of the pre-wet liquid in an annular shape concentric with the substrate. A substrate processing system for processing a substrate using a block copolymer containing a hydrophilic polymer and a hydrophobic polymer,
A block copolymer coating device for supplying the block copolymer coating solution and forming a thin film of the block copolymer;
The block copolymer coating device is:
A first nozzle for supplying a prewetting liquid containing a solvent for the coating solution of the block copolymer to the substrate;
A second nozzle for supplying the block copolymer coating solution to the substrate,
Supplying the pre-wet liquid to the substrate from the first nozzle, and forming a liquid film of the annular pre-wet liquid concentric with the substrate on the substrate;
Supplying the coating solution of the block copolymer from the second nozzle to the substrate after forming the liquid film of the pre-wet liquid, rotating the substrate, and forming a thin film of the block copolymer; Substrate processing system. The substrate processing system according to claim 10, wherein
In the block copolymer coating apparatus, the first nozzle is arranged at a predetermined position on the outer peripheral portion of the substrate, and the substrate is rotated once while the pre-wet liquid is supplied from the first nozzle. An annular pre-wet liquid film is formed. The substrate processing system according to claim 11, wherein
The distance from the center of the substrate to the first nozzle is greater than 3.3% of the radius of the substrate and less than 40% of the radius. The substrate processing system according to claim 11, wherein
The block copolymer coating device is:
The substrate is rotated at a rotational speed faster than the rotational speed of the substrate when the annular pre-wet liquid film is formed, and the annular pre-wet liquid film is spread in the outer peripheral direction of the substrate. The substrate processing system according to claim 10, wherein
The block copolymer coating device rotates the substrate and dries the thin film of the block copolymer. The substrate processing system according to claim 10, wherein
The block copolymer coating apparatus supplies the block copolymer coating liquid from the second nozzle to the center of the substrate. The substrate processing system according to claim 10, wherein
The thickness of the block copolymer thin film is 100 nm or less. The substrate processing system according to claim 10, wherein
The viscosity of the coating solution of the block copolymer is 3 cP or less.

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