JP6177958B2 - Pattern forming method, pattern forming apparatus, and computer-readable storage medium - Google Patents

Description

  The present invention relates to a self-organizing (DSA) lithography technique, a pattern forming method using the technique, a pattern forming apparatus, and a computer-readable storage medium storing a computer program that causes the pattern forming apparatus to perform the pattern forming method.

  In recent years, practical application of self-organized lithography technology using the property that block copolymers are arranged in a self-organized manner has been studied (for example, Patent Documents 1 and 2 and Non-Patent Document 1). In the self-organized lithography technique, first, a solution of a block copolymer including, for example, an A polymer chain and a B polymer chain is applied to a substrate. Next, when the substrate is heated, the A polymer chain and the B polymer chain, which are in solid solution at random, are phase-separated to form regularly arranged A polymer regions and B polymer regions. Next, when either the A polymer region or the B polymer region is removed and the block copolymer is patterned, a mask having a predetermined pattern is formed.

JP 2005-29779 A JP 2007-125699 A

K. W. Guarini, et al. , “Optimization of Diblock Copolymer Thin Film Self Assembly”, Advanced Materials, 2002, 14, no. 18, September 16, pp. 1290-1294. (P. 1290, ll. 31-51)

  As such a block copolymer, for example, a block copolymer (poly (styrene-) in which the A polymer chain is polystyrene (polystyrene: PS) and the B polymer chain is polymethyl methacrylate (poly (methacrylate): PMMA). (block-methyl methacrylate): PS-b-PMMA) is known (Patent Document 1, etc.). As described above, when PS-b-PMMA is applied onto a wafer and the wafer is heated, the phase-separated PS region and PMMA region are regularly arranged. Here, for example, when forming a pattern by removing the PMMA region, the solubility of the PMMA region is high, that is, the solubility of the PMMA region is high, that is, the solubility of the PMMA region is low. Etc. are preferably used. This is because when the solubility ratio is small, the PS region in the pattern formed with the organic solvent becomes thin, and the mask may disappear when the underlying layer is etched using the pattern as an etching mask.

However, since PS and PMMA are organic substances, there is no organic solvent having a large solubility ratio.
Therefore, in Patent Document 1, for example, the block copolymer applied on the substrate is irradiated with an energy beam such as an electron beam, γ-ray, or X-ray, and the irradiated block copolymer is converted into an aqueous solvent or A method of rinsing with an organic solvent has been studied. When the phase-separated PS-b-PMMA is irradiated with energy rays, the main chain of PMMA is cut and easily dissolved in an organic solvent, so that the solubility ratio can be increased. However, it is desirable to increase the solubility ratio between the A polymer region and the B polymer region as much as possible. However, it is difficult to say that a sufficient solubility ratio is achieved.

  In light of the above circumstances, the present invention provides a pattern forming method, a pattern forming apparatus, and a pattern forming method capable of improving the solubility ratio of an A polymer region and a B polymer region in an organic solvent in a block copolymer. A computer-readable storage medium storing a computer program that implements the above is provided.

According to the first aspect of the present invention, a step of forming a block copolymer film containing at least two kinds of polymers on a substrate, a step of heating the block copolymer film, and the heated block a step of irradiating the ultraviolet light peak wavelength to the film of the copolymer is 200nm or less, and a step of supplying organic solvent to the membrane of said block copolymer wherein the ultraviolet light is irradiated see contains, The pattern forming method is provided in which the step of irradiating the ultraviolet light is performed under an atmosphere of an inert gas .

According to the second aspect of the present invention, a coating liquid containing a block copolymer is supplied to a substrate, and a film forming unit that forms a film of the block copolymer on the substrate, and the block is formed by the film forming unit. A heating unit that heats the substrate on which the copolymer film is formed, an ultraviolet light irradiation unit that irradiates the heated block copolymer film with ultraviolet light having a peak wavelength of 200 nm or less, and A liquid treatment unit that supplies an organic solvent to the block copolymer film irradiated with ultraviolet light, and the ultraviolet light irradiation unit includes an inert gas supply unit that supplies an inert gas therein. A pattern forming apparatus is provided that irradiates the ultraviolet light under an inert gas atmosphere .

  Another aspect of the present invention is a computer-readable storage medium that stores a computer program that causes a pattern forming apparatus to perform the pattern forming method described above.

  According to this invention, the solubility ratio with respect to the organic solvent of the A polymer area | region and B polymer area | region in a block copolymer can be improved rather than before.

It is a figure explaining the pattern formation method by the 1st Embodiment of this invention. It is a figure explaining the example applied when the pattern formation method by the 1st Embodiment of this invention forms a hole in a board | substrate. It is an upper surface image by the scanning electron microscope (SEM) which shows the hole formed according to the pattern formation method by the 1st Embodiment of this invention. It is a cross-sectional image by SEM which shows the hole formed according to the pattern formation method by the 1st Embodiment of this invention. It is a perspective view which shows the pattern formation apparatus by the 2nd Embodiment of this invention. It is a top view which shows the pattern formation apparatus of FIG. It is another perspective view which shows the pattern formation apparatus of FIG. It is a schematic diagram which shows the liquid processing unit of the pattern formation apparatus of FIG. It is a schematic diagram which shows the ultraviolet light irradiation unit of the pattern formation apparatus of FIG. It is the graph which showed the absorption coefficient with respect to the wavelength of the ultraviolet light of PS, PMMA, and PS-b-PMMA.

  Hereinafter, non-limiting exemplary embodiments of the present invention will be described with reference to the accompanying drawings. In the accompanying drawings, the same or corresponding parts or members are denoted by the same or corresponding reference numerals, and redundant description is omitted.

(First embodiment)
A pattern forming method according to a first embodiment of the present invention will be described with reference to FIG. First, a solution (also referred to as a coating solution) in which a polystyrene (PS) -polymethyl methacrylate (PMMA) block copolymer (hereinafter referred to as PS-b-PMMA) is dissolved in an organic solvent is prepared. The organic solvent is not particularly limited as long as it is highly compatible with PS and PMMA constituting PS-b-PMMA, and may be, for example, toluene, propylene glycol monomethyl ether acetate (PGMEA), or the like.

  Next, when a coating solution is applied onto a semiconductor wafer (hereinafter simply referred to as a wafer) W as a substrate, for example, by spin coating, a PS-b-PMMA film 21 is formed as shown in FIG. The In this film 21, as schematically shown in the inset in FIG. 1A, the PS polymer and the PMMA polymer are randomly mixed with each other.

  Next, as shown in FIG. 1B, when the wafer W on which the PS-b-PMMA film 21 is formed is heated to a predetermined temperature by, for example, a hot plate HP, phase separation occurs in the PS-b-PMMA. Due to this phase separation, as shown in the inset in FIG. 1B, the PS regions DS and the PMMA regions DM are alternately arranged. Here, since the width of the PS region DS is determined by an integer multiple of the molecular length of PS, and the width of the PMMA region DM is determined by an integer multiple of the molecular length of PMMA, the PS region DS in the PS-b-PMMA film 21 is determined. And the PMMA area DM is repeatedly arranged at a predetermined pitch (the width of the PS area DS + the width of the PMMA area DM). Further, since the width of the PS region DS is determined by the number of polymerization of PS molecules and the width of the PMMA region DM is determined by the number of polymerization of PMMA molecules, a desired pattern can be determined by adjusting the number of polymerization. Note that it is preferable to form a guide pattern on the surface of the wafer W in order to arrange the PS region DS and PMMA region DM of PS-b-PMMA in a predetermined pattern.

  After the heating, as shown schematically in FIG. 1C, a rare gas such as argon (Ar) or helium (He) or nitrogen gas is applied to the PS-b-PMMA film 21 on the wafer W. For example, the light source L irradiates ultraviolet light under an inert gas atmosphere such as. Although ultraviolet light will not be specifically limited if it has the wavelength component which belongs to an ultraviolet light area | region, For example, it is preferable to have a wavelength component of 200 nm or less. Further, it is more preferable that the ultraviolet light includes a wavelength component of 185 nm or less that can be absorbed by PMMA. When using ultraviolet light having a wavelength component of 200 nm or less, an Xe excimer lamp that emits ultraviolet light having a wavelength of 172 nm can be suitably used as the light source L.

  When the PS-b-PMMA film 21 is irradiated with ultraviolet light, a cross-linking reaction occurs in PS, so that PS hardly dissolves in an organic solvent, whereas in PMMA, the main chain is cut, so PMMA is organic. It is thought that it becomes easy to dissolve in a solvent. When ultraviolet light having a wavelength of 172 nm is used, the irradiation intensity (dose amount) is preferably about 180 mJ or less. When the PS-b-PMMA film 21 is irradiated with ultraviolet light having a wavelength of 172 nm with a dose amount greater than 180 mJ, when the organic solvent is supplied to the PS-b-PMMA film 21 later, the organic solvent enters the PS region DS. This is because the penetration becomes easy, and as a result, the PS region DS swells and the PMMA region DM is hardly removed. Furthermore, when the dose amount of ultraviolet light is larger than 180 mJ, the PMMA region DM may be denatured and solidified, and may be difficult to dissolve in an organic solvent.

  Note that the oxygen concentration in the atmosphere around the wafer W is lowered by the inert gas. Specifically, as described later, the oxygen concentration in the inert gas atmosphere is, for example, 400 ppm or less.

  Next, as shown in FIG. 1D, the organic solvent OS is supplied to the PS-b-PMMA film 21. The organic solvent OS dissolves the PMMA region DM in the film 21 and the PS region DS remains on the surface of the wafer W. Here, as the organic solvent OS, for example, isopropyl alcohol (IPA) can be preferably used.

  When the surface of the wafer W is dried after a predetermined time has elapsed, a pattern based on the PS region DS is obtained on the surface of the wafer W as shown in FIG.

  Next, an example in which the pattern forming method according to the embodiment of the present invention is applied to the case where holes (corresponding to contact holes or via holes) are formed in a substrate (for example, a silicon wafer) will be described with reference to FIG. In the following description, irradiation of ultraviolet light onto a PS-b-PMMA film is sometimes referred to as exposure, and dissolution of the PMMA region with an organic solvent is sometimes referred to as development. 2A to FIG. 2D are top views, and FIG. 2A to FIG. 2D are II corresponding to FIG. 2A to FIG. 2D. It is sectional drawing along a line.

First, a photoresist layer PL is formed on the surface of the wafer W, and a plurality of holes H are formed in the photoresist layer PL as shown in FIGS. 2A and 2A. Two holes H are shown). The hole H can be formed by a conventional photolithography technique. The inner diameter of the hole H may be about 90 nm, for example.
Next, for example, toluene is used as a solvent, and PS-b-PMMA is dissolved in this solvent to prepare a coating solution. The solid component concentration of PS-b-PMMA in the coating solution may be, for example, 2% by volume. A coating liquid is applied onto the photoresist layer PL and the wafer W by a spin coater, for example, to form a PS-b-PMMA film 21. Here, as shown in FIGS. 2B and 2B, the hole H is filled with a film 21 of PS-b-PMMA. At this time, PS and PMMA are randomly mixed with each other.

When the wafer W on which the PS-b-PMMA film 21 is formed is heated on a hot plate at a temperature of about 150 ° C. to about 250 ° C. for about 30 seconds to about 10 minutes, PS and PMMA are phase-separated. As a result, as shown in FIGS. 2C and 2C, a PS region DS having a cylindrical shape is arranged along the inner wall of the hole H, and a PMMA region DM having a columnar shape is formed at the center of the PS region DS. Be placed.
After cooling the wafer W to about room temperature, the PS-b-PMMA film 21 is irradiated with ultraviolet light (wavelength 172 nm), for example, for about 10 seconds to about 60 seconds (exposure) using an Xe excimer lamp in an inert gas atmosphere. To do.
After the exposure, for example, in a liquid processing unit described later, an organic solvent (for example, IPA) is dropped on the wafer W on which the PS-b-PMMA film 21 is formed, and IPA is deposited on the film 21. For example, after about 3 minutes from about 30 seconds, the IPA is dried by rotating the wafer W. Thereby, as shown in FIGS. 2D and 2D, a hole h defined by the PS region DS is formed. The hole h has an inner diameter smaller than the inner diameter (90 nm) of the hole H formed in the photoresist layer PL. The inner diameter of the hole h can be adjusted by the mixing ratio of PS and PMMA of PS-b-PMMA, and is about 30 nm in this example. When the underlying wafer W is etched using the PS-b-PMMA film 21 having such a hole h as a mask, a hole having an inner diameter substantially equal to the inner diameter of the hole h is formed in the wafer W. As described above, according to the pattern forming method of the present embodiment, it is possible to obtain a hole h having an inner diameter smaller than a limit dimension (for example, about 60 nm) that can be realized by a conventional photolithography technique.

  Next, the results of forming holes h (FIGS. 2D and 2D) according to the above-described method as Example 1 and observing them with a scanning electron microscope (SEM) will be described. In this example, nitrogen gas was used to generate an inert gas atmosphere when the PS-b-PMMA film on the wafer was exposed to ultraviolet light (wavelength 172 nm). Moreover, the oxygen concentration in nitrogen gas atmosphere was adjusted with 6 ppm, 150 ppm, and 400 ppm. As a comparative example, an experiment was also conducted in the case where the PS-b-PMMA film 21 was exposed to ultraviolet light (wavelength: 172 nm) in an air atmosphere. These results (SEM images) are shown in FIG.

  As shown in FIGS. 3A to 3C, when the PS-b-PMMA film is exposed to ultraviolet light in an inert gas atmosphere, a hole h in the PS region is opened. On the other hand, as shown in FIG. 3 (d), when the film of PS-b-PMMA is exposed to ultraviolet light in an air atmosphere, the holes are compared with the holes shown in FIGS. 3 (a) to 3 (c). (Note that the magnification of the SEM image in FIG. 3 (d) is larger than the magnification of the SEM images in FIGS. 3 (a) to 3 (c)), and no holes are formed. Is occasionally seen. Under an atmosphere containing a high concentration of oxygen (the oxygen concentration in the air is about 20%), the PS-b-PMMA film is excessively oxidized and altered by ultraviolet light, so that the PMMA region is dissolved in IPA. It is thought that it becomes difficult to put out. Further, referring to FIG. 3D, since the surface (the surface of the PS region) is rough, it is considered that the PS region is also excessively oxidized and deteriorated.

  On the other hand, since excessive oxidation of PMMA is suppressed in an inert gas atmosphere, it is considered that alteration of the PS-b-PMMA film is prevented. In particular, referring to FIGS. 3 (a) to 3 (c), if the oxygen concentration in the inert gas atmosphere is about 400 ppm or less, it is estimated that neither PS nor PMMA is altered by ultraviolet light. . From the above results, the effect of exposing the PS-b-PMMA film with ultraviolet light in an inert gas atmosphere is understood.

  Next, the results of examining the film thickness change in the PMMA area before and after development will be described. FIG. 4 is an SEM image showing a cross section of a hole formed according to the above-described method. FIG. 4 is a cross-sectional image obtained by cutting the wafer W, the photoresist layer PL, and the PS region along the line II in FIG. 2D and observing with a SEM from a direction perpendicular to the cut surface. However, the PS region in the hole H is removed, and the hole H is visible instead of the hole h.

  FIG. 4A shows a cross-sectional image before development by IPA, and the thickness of the PS region DS on the photoresist layer PL is about 15 nm. FIG. 4B shows a cross-sectional image after development. Also in FIG. 4B, the thickness of the PS region DS on the photoresist layer PL is about 15 nm. That is, the PS region DS is hardly dissolved in IPA. Considering that the PMMA region is almost completely dissolved by development, the solubility ratio (PMMA solubility / PS solubility) becomes almost infinite.

  For comparison, FIG. 4C shows a result of developing a PS-b-PMMA film with oxygen plasma by a reactive ion etching (RIE) apparatus. As shown in FIG. 4C, the thickness of the PS region DS remaining on the photoresist layer PL is about 10 nm. According to this result, the etching rate ratio (PMMA etching rate / PS etching rate) by RIE oxygen plasma is about 7. From these results, it can be said that the pattern forming method according to the present embodiment has a significant effect on the development by RIE.

(Second Embodiment)
Next, referring to FIG. 5 to FIG. 9, the pattern forming apparatus according to the second embodiment of the present invention suitable for performing the pattern forming method (including the hole forming method) according to the first embodiment. Will be described. FIG. 5 is a schematic perspective view showing the pattern forming apparatus 10 according to the present embodiment, and FIG. 6 is a schematic top view showing the pattern forming apparatus 10. 5 and 6, the pattern forming apparatus 10 includes a cassette station S1, a processing station S2, and an interface station S3.

In the cassette station S1, a cassette stage 24 and a transfer arm 22 (FIG. 6) are provided. On the cassette stage 24, a plurality (four in the illustrated example) of cassettes C that can accommodate a plurality of (for example, 25) wafers W are placed. In the following description, the direction in which the cassettes C are arranged is referred to as the X direction for the sake of convenience, and the direction orthogonal thereto is referred to as the Y direction.
Since the transfer arm 22 transfers the wafer W between the cassette C on the cassette stage 24 and the processing station S2, the transfer arm 22 can move up and down, can move in the X direction, can expand and contract in the Y direction, and can rotate about the vertical axis. It is configured.

  The processing station S2 is coupled to the cassette station S1 on the + Y direction side. In the processing station S2, two coating units 32 are arranged along the Y direction, and above these, the liquid processing unit 31 and the ultraviolet light irradiation unit 40 are arranged in this order in the Y direction (FIG. 5). . Referring to FIG. 6, the shelf unit R1 is disposed on the + X direction side with respect to the coating unit 32 and the liquid processing unit 31, and the shelf unit R2 is disposed on the + X direction side with respect to the coating unit 32 and the ultraviolet light irradiation unit 40. Has been placed. In the shelf units R1 and R2, processing units corresponding to processing performed on the wafer are stacked as will be described later.

  A main transport mechanism MA (FIG. 6) is provided almost at the center of the processing station S 2, and the main transport mechanism MA has an arm 71. The arm 71 can move up and down and move in the X and Y directions in order to carry the wafer W in and out of the coating unit 32, the liquid processing unit 31, the ultraviolet light irradiation unit 40, and the processing units of the shelf units R1 and R2. It is possible to rotate around the vertical axis.

As shown in FIG. 7, the shelf unit R1 includes a heating unit 61 for heating the wafer W, a cooling unit 62 for cooling the wafer W, a hydrophobizing unit 63 for hydrophobizing the wafer surface, and a wafer W temporarily. A pass unit 64 having a stage placed on the substrate and an alignment unit 65 for aligning the wafer W are arranged in the vertical direction. In the shelf unit R2, a plurality of CHP units 66 for heating and then cooling the wafer W, a pass unit 67 having a stage on which the wafer W is temporarily placed, and the like are arranged in the vertical direction. Note that the types and arrangement of the units in the shelf units R1 and R2 are not limited to those shown in FIG. 7, and may be variously changed.

  Next, the liquid processing unit 31 will be described with reference to FIG. The liquid processing unit 31 includes a housing 31C, and the spin chuck 2 that rotatably holds the wafer W in the housing 31C and the surface of the wafer W held by the spin chuck 2 are movable. The chemical solution supply nozzle 5 for supplying (discharging) the organic solvent to the wafer W and the outer periphery of the wafer W held by the spin chuck 2 are surrounded by the chemical solution supply nozzle 5 and supplied to the surface of the wafer W. And a cup 6 that receives the organic solvent scattered by the rotation. A loading / unloading port (not shown) for the wafer W is provided on one side wall of the housing 31C, and the loading / unloading port can be opened and closed by a shutter (not shown).

  For example, the cup 6 is formed in a cylindrical shape whose bottom surface is closed and whose top surface is open. An exhaust port 6 a and a drain port 6 b are provided at the bottom of the cup 6. An exhaust pipe 16 connected to an exhaust device (not shown) such as an exhaust pump is connected to the exhaust port 6a. Further, for example, a discharge pipe 17 connected to a factory drain (not shown) is connected to the drain 6b, and the organic solvent recovered by the cup 6 is discharged to the outside of the liquid processing unit 31.

  For example, a servo motor 12 is connected to the spin chuck 2. The servo motor 12 rotates the spin chuck 2 and the wafer W held by the spin chuck 2 at a predetermined rotation speed.

  Further, for example, three support pins 14 for supporting the wafer W and moving up and down are provided so as to surround the spin chuck 2 (two support pins 14 are shown in FIG. 8). The support pin 14 can be moved up and down through a through hole (not shown) formed in the bottom of the cup 6 by a lifting drive mechanism 15 such as a cylinder. The support pins 14 can be projected to a position higher than the upper surface of the spin chuck 2 by the lift drive mechanism 15, and the wafer W can be transferred to the spin chuck 2.

As shown in FIG. 8, the chemical solution supply nozzle 5 is supported by a rotation / lifting arm 25 that is disposed outside the cup 6 and is connected to a moving mechanism 20 having a horizontal rotation and a lifting function. By the moving mechanism 20, the chemical solution supply nozzle 5 can be moved between an outer position of the cup 6 (position indicated by a dotted line) and a position above the center of the wafer W (position indicated by a solid line). The chemical solution supply nozzle 5 is connected to a chemical solution supply source 39 for storing an organic solvent via a chemical solution supply pipe 39C, and can supply the organic solvent supplied from the chemical solution supply source 39 to the wafer W. it can. In the present embodiment, the branch pipe 39B is connected to the chemical liquid supply pipe 39C, and the branch pipe 39B is connected to the additive supply source 39A. In the additive supply source 39A, for example, a hydrophobizing agent (described later) such as a silylating agent is stored, and the hydrophobizing agent is applied to the organic solvent supplied from the chemical solution supply source 39 by switching a valve (not shown). Can be added.
Needless to say, the chemical solution supply pipe 39C and the branch pipe 39B may be provided with a flow rate regulator for adjusting the flow rates of the organic solvent and the hydrophobizing agent.

A rinse liquid discharge nozzle 8 for supplying a rinse liquid toward the wafer W held by the spin chuck 2 is provided outside the cup 6. The rinse liquid discharge nozzle 8 is provided with a standby portion 8a. The rinse liquid discharge nozzle 8 can be moved between the upper center of the wafer W and the standby unit 8a by a moving mechanism and a rotation / lifting arm (not shown) as in the case of the chemical liquid supply nozzle 5. The rinsing liquid discharge nozzle 8 is connected to a rinsing liquid supply source (not shown) installed outside the liquid processing unit 31 via a rinsing liquid supply pipe (not shown), thereby rinsing liquid supply source. The rinsing liquid supplied from the wafer W can be supplied to the wafer W.

  The coating unit 32 (FIG. 5) has the same configuration as the liquid processing unit 31. However, the chemical solution supply source 39 stores, for example, a solution (coating solution) obtained by dissolving PS-b-PMMA in an organic solvent, and PS-b-PMMA is supplied from the chemical solution supply nozzle 5. A duplicate description of the coating unit 32 is omitted.

  5 and 6, the interface station S3 is coupled to the + Y direction side of the processing station S2, and the exposure apparatus 200 is coupled to the + Y direction side of the interface station S3. The exposure apparatus 200 can be used to form the hole H of the photoresist layer PL in the formation of the hole h described with reference to FIG.

  Further, a transport mechanism 76 (FIG. 6) is disposed at the interface station S3. The transfer mechanism 76 can move up and down, move in the X direction, and expand and contract in the Y direction to load and unload the wafer W between the pass unit 67 (FIG. 7) of the shelf unit R2 in the processing station S2 and the exposure apparatus 200. It is possible to rotate around the vertical axis.

  Further, as shown in FIG. 6, the pattern forming apparatus 10 is provided with a control unit 100 for controlling the operation of the entire apparatus. The control unit 100 includes a processor formed by a CPU (Central Processing Unit), an MPU (Micro Processing Unit), etc., and a process controller 100a for controlling each component or member of the pattern forming apparatus 10, a user interface unit 100b, A storage unit 100c is provided.

  The user interface unit 100 b includes a keyboard that allows a process manager to input commands to manage the pattern forming apparatus 10, a display that displays an operation status of the pattern forming apparatus 10, and the like.

  The storage unit 100c stores a recipe that stores a control program (software), processing condition data, and the like for realizing various processes executed by the pattern forming apparatus 10 under the control of the process controller 100a. If necessary, an arbitrary recipe is called from the storage unit 100c according to an instruction from the user interface unit 100b and is executed by the process controller 100a, so that the pattern forming apparatus 10 can perform a desired process under the control of the process controller 100a. The function is executed to perform a desired process. That is, for example, the program controls the computer so that the pattern forming apparatus 10 functions as a unit that executes a pattern forming method described later. The program (and recipe such as processing condition data) is stored in a computer-readable program recording medium 100d (for example, a hard disk, a compact disk, a magneto-optical disk, a memory card, a flexible disk, etc.). It is installed in the storage unit 100c through an input / output (I / O) device (not shown). Or you may install in the memory | storage part 100c from another apparatuses, such as a server apparatus, for example via a dedicated line.

  Next, the ultraviolet light irradiation unit 40 will be described with reference to FIG. As shown in FIG. 9, the ultraviolet light irradiation unit 40 includes a wafer chamber 51 in which the wafer W is accommodated, and a light source chamber 52 that irradiates the wafer W accommodated in the wafer chamber 51 with ultraviolet light. Yes.

  The wafer chamber 51 includes a housing 53, a transmission window 54 that is provided on the ceiling of the housing 53 and can transmit ultraviolet light, and a susceptor 57 on which the wafer W is placed. The transmission window 54 is made of, for example, quartz glass.

  The susceptor 57 has a disk shape and has a heater 68 inside. The heater 68 is connected to a temperature regulator 69, whereby the temperature of the susceptor 57 is adjusted to a predetermined temperature. A plurality of (for example, three) support pins 58 that support the wafer W are provided on the upper surface of the susceptor 57. The susceptor 57 has a diameter equal to or slightly larger than that of the wafer W, and is preferably formed of a thermal conductivity having a high thermal conductivity, such as silicon carbide (SiC) or aluminum.

  The plurality of support pins 58 have a function of suppressing excessive heating of the wafer W and promoting cooling of the heated wafer W. For this reason, it is desirable that the support pins 58 be formed of a material having a high thermal conductivity of, for example, 100 W / (m · k) or more, for example, silicon carbide (SiC). In order to promote heat conduction from the wafer W to the susceptor 57, the number of support pins 58 is not limited to three, and a larger number of support pins 58 may be provided.

  Further, as shown in FIG. 9, a cooling water flow channel 55 a is formed inside the base plate 55. Then, cooling water is supplied from the cooling water supply device 70 to the flowing water passage 55a, and the entire base plate 55 is cooled to a predetermined temperature. Moreover, it is preferable that the support | pillar 56 provided on the baseplate 55 and supporting the susceptor 57 is formed, for example with aluminum.

The wafer chamber 51 is moved up and down through the base plate 55 and the susceptor 57 to support the wafer W from below when the wafer W is loaded and unloaded, and the lift pins 59 are moved up and down. A lifting mechanism 60 is provided.
In addition, a wafer W loading / unloading port (not shown) is formed on one side wall of the casing 53, and the wafer W is loaded into the wafer chamber 51 by the arm 71 of the main transfer mechanism MA through the wafer 53. It is carried out from 51. A shutter (not shown) is provided at the loading / unloading port, and the loading / unloading port is opened and closed by the shutter. It is preferable that the shutter can close the loading / unloading port in an airtight manner.

  Further, an inert gas introduction port 51 </ b> A is provided on the side wall of the housing 53, and an inert gas exhaust port 51 </ b> B is provided on the bottom of the housing 53. An inert gas supply source 81 in which an inert gas is stored (filled) is connected to the inert gas introduction port 51A, and the inert gas supply source 81 passes through the inert gas introduction port 51A to the inside of the wafer chamber 51. Active gas is supplied.

  On the other hand, the light source chamber 52 disposed above the wafer chamber 51 includes a light source L that irradiates the wafer W in the wafer chamber 51 with ultraviolet light, and a power source 72 that supplies power to the light source L. The light source L is accommodated in the housing 73. An irradiation window 74 is provided at the bottom of the housing 73 in order to transmit the ultraviolet light emitted from the light source L to the wafer chamber 51. The irradiation window 74 is made of, for example, quartz glass. Ultraviolet light from the light source L is emitted toward the wafer chamber 51 through the irradiation window 74, and ultraviolet light that has passed through the transmission window 54 of the wafer chamber 51 is irradiated onto the wafer W.

In the ultraviolet light irradiation unit 40 configured as described above, the PS-b-PMMA film formed on the wafer W by the coating unit 32 is heated and exposed as follows. That is, the wafer W on which the PS-b-PMMA film is formed is loaded into the wafer chamber 51 by the arm 71 of the main transfer mechanism MA, received by the lift pins 59, and placed on the support pins 58 on the susceptor 57.
After the arm 71 of the main transfer mechanism MA is withdrawn from the wafer chamber 51, the shutter is closed and the inside of the wafer chamber 51 is isolated from the external environment. When an inert gas such as nitrogen gas is supplied from the inert gas supply source 81 into the wafer chamber 51 for a predetermined time, the air remaining in the wafer chamber 51 is purged. As a result, the inside of the wafer chamber 51 becomes an inert gas atmosphere.

  While the inside of the wafer chamber 51 is purged with an inert gas, the wafer W supported by the support pins 58 is heated to a predetermined temperature by the heater 68 of the susceptor 57. When the supply of power to the heater 68 is stopped after a predetermined time has elapsed, the heat of the wafer W is transmitted to the base plate 55 through the support pins 58 and the susceptor 57, and the wafer W is cooled to, for example, about room temperature (about 23 ° C.). .

  After the wafer W reaches about room temperature, power is supplied from the power source 72 to the light source L, and ultraviolet light is emitted from the light source L. The ultraviolet light is irradiated on the surface of the wafer W under an inert gas atmosphere through the irradiation window 74 of the light source chamber 52 and the transmission window 54 of the wafer chamber 51. Since the dose required for the exposure of the PS-b-PMMA film is determined by “illuminance × irradiation time”, it is preferable to determine the irradiation time according to the illuminance of ultraviolet light through, for example, a preliminary experiment.

After the ultraviolet irradiation for a predetermined time, the wafer W is unloaded from the ultraviolet light irradiation unit 40 by a procedure reverse to that for loading the wafer W. Thereafter, the wafer W is transferred to the liquid processing unit 31 where the PS-b-PMMA film is developed with an organic solvent (for example, IPA). That is, the PMMA region is melted and a pattern constituted by the PS region is obtained.
According to the pattern forming apparatus 10 according to the second embodiment, the pattern forming method according to the first embodiment can be suitably implemented. That is, the effects and advantages exhibited by the pattern forming method according to the first embodiment are also exhibited by the pattern forming apparatus 10 according to the second embodiment.

  As described above, according to the pattern forming method and the pattern forming apparatus according to the embodiment of the present invention, PS-b-PMMA block copolymer in which phase separation occurs due to heating and PS regions and PMMA regions are regularly arranged. This film is exposed to ultraviolet light in an inert gas atmosphere and developed with an organic solvent, whereby a fine pattern of PS regions can be formed. And since it exposes in inert gas atmosphere, the excessive reaction of PMMA and oxygen by ultraviolet light can be suppressed. For this reason, alteration of PMMA can be suppressed, and therefore, a decrease in solubility of PMMA in an organic solvent can be prevented. As a result, the solubility of PMMA in IPA can be made higher than the solubility of PS, and the solubility ratio can be improved. In addition, since exposure with ultraviolet light is performed in an inert gas atmosphere, an excessive reaction between PS and oxygen due to ultraviolet light can be suppressed, and PS alteration can also be suppressed. For this reason, the solubility ratio can be further improved.

  The present invention has been described above with reference to the preferred embodiments of the present invention. However, the present invention is not limited to the above-described embodiments, and is within the scope of the gist of the present invention described in the claims. Various modifications and changes can be made.

  Although an example of forming holes in the first embodiment has been described, the pattern forming method according to the embodiment of the present invention can also be applied to the formation of a line and space pattern. In this case, for example, the line may fall due to the surface tension of the IPA when the substrate is dried after forming the line composed of the PS region by development with an organic solvent such as IPA. In order to prevent this, it is preferable to reduce the surface tension by adding a hydrophobizing agent such as a silylating agent to IPA. Examples of silylating agents that can be added to IPA include trimethylsilyldimethylamine (TMSDMA), dimethylsilyldimethylamine (DMSDMA), trimethylsilyldiethylamine (TMSDEA), hexamethylzinelazan (HMDS), and trimethylzinelazan (TMDS). In the case of adding a hydrophobizing agent to the organic solvent, the hydrophobizing agent may be added to the organic solvent from the additive supply source 39A of the coating unit 32 in the second embodiment through the branch pipe 39B, or to the chemical solution supply source 39. An organic solvent to which a hydrophobizing agent is added may be stored in advance.

  Further, after developing with an organic solvent such as IPA, the organic solvent may be rinsed with a liquid having a smaller surface tension. Examples of such a liquid include alcohols such as methyl alcohol and ethyl alcohol. Such a liquid can be supplied to the wafer W from the rinse liquid discharge nozzle 8 of the liquid processing unit 31 of FIG.

  In the above-described embodiment, PS-b-PMMA is exemplified as the block copolymer. However, the block copolymer is not limited thereto. For example, polybutadiene-polydimethylsiloxane, polybutadiene-4-vinylpyridine, polybutadiene-methyl methacrylate. , Polybutadiene-poly-t-butyl methacrylate, polybutadiene-t-butyl acrylate, poly-t-butyl methacrylate-poly-4-vinyl pyridine, polyethylene-polymethyl methacrylate, poly-t-butyl methacrylate-poly-2-vinyl pyridine , Polyethylene-poly-2-vinylpyridine, polyethylene-poly-4-vinylpyridine, polyisoprene-poly-2-vinylpyridine, polymethyl methacrylate-polystyrene, poly-t-butyl methacrylate -Polystyrene, polymethylacrylate-polystyrene, polybutadiene-polystyrene, polyisoprene-polystyrene, polystyrene-poly-2-vinylpyridine, polystyrene-poly-4-vinylpyridine, polystyrene-polydimethylsiloxane, polystyrene-poly-N, N- Examples include dimethylacrylamide, polybutadiene-sodium polyacrylate, polybutadiene-polyethylene oxide, poly-t-butyl methacrylate-polyethylene oxide, polystyrene-polyacrylic acid, and polystyrene-polymethacrylic acid.

  The organic solvent for developing the PS-b-PMMA film is not limited to IPA, and for example, methyl alcohol, ethyl alcohol, acetone, xylene, or the like can be used. In addition, when using a block copolymer with a photoresist like the case of the example which forms the above-mentioned hole, it is preferable to use IPA as an organic solvent. This is because the photoresist is difficult to dissolve in IPA.

  Further, when the PS-b-PMMA film is developed with an organic solvent, the temperature of the organic solvent may be increased according to the organic solvent used. In the case of IPA, for example, it is preferable to raise the temperature to, for example, 40 ° C. to 60 ° C. By increasing the temperature, the solubility of the PMMA region in the organic solvent can be increased.

  In the above-described embodiment, the Xe excimer lamp that emits ultraviolet light having a wavelength of 172 nm is exemplified as the ultraviolet light source L. For example, a low-pressure ultraviolet lamp (low-pressure mercury lamp) that emits ultraviolet light having strong peaks at wavelengths of 185 nm and 254 nm Alternatively, a KrCl excimer lamp that emits single wavelength light having a wavelength of 222 nm may be used. For example, the light source L may be constituted by a lamp having a relatively broad emission spectrum from the far ultraviolet region to the vacuum ultraviolet region and a wavelength cut filter that shields a wavelength longer than, for example, about 230 nm.

  However, the wavelength of ultraviolet light used in the present invention is most preferably 172 nm. FIG. 10 is a graph showing the absorption coefficient of PS, PMMA, and PS-b-PMMA with respect to the wavelength of ultraviolet light. According to the graph, at 193 nm, the PS-b-PMMA as a whole has a high absorption coefficient. It can be seen that However, at 193 nm, the absorption coefficient of PMMA itself is extremely low. Therefore, in fact, at 193 nm, the progress of the main chain cleavage reaction in PMMA is slow, and as a result, processing takes time.

In this respect, at 172 nm, both PS and PMMA show relatively high absorption coefficients, and both the crosslinking reaction in PS and the main chain separation reaction in PMMA proceed relatively quickly. Therefore, the processing time is shortened compared with the case of 193 nm. According to the graph, a relatively high absorption coefficient is obtained for both PS and PMMA even at wavelengths shorter than 172 nm. However, when the wavelength is shortened, the ultraviolet light irradiation atmosphere requires a lower oxygen concentration. For example, at 160 nm, a substantially vacuum state is required. On the other hand, 172 nm ultraviolet light is sufficient even under an inert gas atmosphere such as nitrogen gas as described above. In addition, by using an Xe gas-filled lamp as the light source, a single-wavelength lamp can be obtained and energy efficiency is good, unlike a mercury lamp.
Therefore, in view of these points, the wavelength of the ultraviolet light used in the present invention is most preferably 172 nm.

  Further, the irradiation time of ultraviolet light can be appropriately adjusted according to the block copolymer used, the thickness of the block copolymer, the intensity of the ultraviolet light used, and the like.

  In the second embodiment, the pattern forming apparatus 10 in which the liquid processing unit 31 and the ultraviolet light irradiation unit 40 are incorporated has been described. However, the liquid processing unit 31 and the ultraviolet light irradiation unit 40 are different from each other in the pattern forming apparatus 10. It may be provided separately from the pattern forming apparatus 10 without being incorporated into the pattern forming apparatus 10. In other embodiments, the liquid processing unit 31 and the ultraviolet light irradiation unit 40 may be integrally configured. Further, the pattern forming apparatus according to another embodiment may be configured by combining the liquid processing unit 31, the coating unit 32, and the ultraviolet light irradiation unit 40. The susceptor 57 of the ultraviolet light irradiation unit 40 includes a heater 68, and the block copolymer film is heated in the ultraviolet light irradiation unit 40. A heating unit for heating the block copolymer film is provided. You may provide separately from the ultraviolet light irradiation unit 40 instead of in the ultraviolet light irradiation unit 40. FIG.

DESCRIPTION OF SYMBOLS 21 ... Film PL ... Photoresist layer S1 ... Cassette station S2 ... Processing station S3 ... Interface station 31 ... Liquid processing unit 5 ... Chemical supply nozzle 32 ... Coating unit 39 ... Chemical solution supply source 39A ... Additive supply source 40 ... Ultraviolet light irradiation unit 51 ... Wafer chamber 52 ... Light source chamber 57 ... Susceptor 58 ... Support pin 68 ... Heater 81 ... Inert gas supply source OS ... Organic solvent DS ... PS region DM ... PMMA region W ... Wafer L ... Light source

Claims (13)

Forming a block copolymer film comprising at least two polymers on a substrate;
Heating the block copolymer film;
Irradiating the heated block copolymer film with ultraviolet light having a peak wavelength of 200 nm or less;
Supplying an organic solvent to the block copolymer film irradiated with the ultraviolet light;
Only including,
The step of irradiating the ultraviolet light is a pattern forming method performed in an atmosphere of an inert gas . The block copolymer is polystyrene-polymethyl methacrylate, polybutadiene-polydimethylsiloxane, polybutadiene-4-vinylpyridine, polyethylene-poly-2-vinylpyridine, polyisoprene-poly-2-vinylpyridine, polybutadiene-polystyrene, polyisoprene. 2. Polystyrene, polystyrene-poly-2-vinylpyridine, polystyrene-polydimethylsiloxane, polystyrene-poly-N, N-dimethylacrylamide, polybutadiene-sodium polyacrylate, or polybutadiene-polyethylene oxide. Pattern forming method. The pattern formation method of Claim 1 or 2 whose oxygen concentration in the said inert gas is 400 ppm or less. The pattern formation method as described in any one of Claim 1 to 3 with which a hydrophobizing agent is added to the said organic solvent. The pattern formation method as described in any one of Claim 1 to 4 whose said organic solvent is isopropyl alcohol. Prior membranes the block copolymer to form the substrate, the substrate, further forming a photoresist layer having a recess comprising, according to any one of claims 1 5 pattern Forming method. Supplying a coating liquid containing a block copolymer to the substrate, and forming a film of the block copolymer on the substrate;
A heating unit that heats the substrate on which the block copolymer film is formed by the film forming unit;
An ultraviolet light irradiation unit for irradiating the heated block copolymer film with ultraviolet light having a peak wavelength of 200 nm or less;
A liquid treatment unit for supplying an organic solvent to the block copolymer film irradiated with the ultraviolet light;
Equipped with a,
The pattern forming apparatus , wherein the ultraviolet light irradiation unit includes an inert gas supply unit that supplies an inert gas therein, and irradiates the ultraviolet light in an inert gas atmosphere . The block copolymer is polystyrene-polymethyl methacrylate, polybutadiene-polydimethylsiloxane, polybutadiene-4-vinylpyridine, polyethylene-poly-2-vinylpyridine, polyisoprene-poly-2-vinylpyridine, polybutadiene-polystyrene, polyisoprene. - polystyrene, polystyrene - poly-2-vinylpyridine, polystyrene - polydimethylsiloxane, polystyrene - poly -N, N-dimethyl acrylamide, polybutadiene - sodium polyacrylate or polybutadiene - polyethylene oxide, according to claim 7 Pattern forming device. Wherein the heating unit is provided in the ultraviolet light irradiation portion, the pattern forming apparatus according to claim 7 or 8. The pattern forming apparatus according to claim 7 , wherein the inert gas supply unit stores an inert gas having an oxygen concentration of 400 ppm or less. The first source of the organic solvent is stored are provided, the pattern forming apparatus according to any one of claims 7 to 10 to the liquid processing section. The liquid processing unit is provided with a second supply source in which the hydrophobizing agent is stored,
The pattern forming apparatus according to claim 11 , wherein the second supply source and the first supply source are connected by a predetermined pipe. A computer-readable storage medium storing a computer program for controlling the pattern forming apparatus to cause the pattern forming apparatus according to claim 7 to execute the pattern forming method according to any one of claims 1 to 6 .