JP4392431B2 - Barrier film forming material and pattern forming method using the same - Google Patents

Description

  The present invention relates to a barrier film forming material formed on a resist film and used in a semiconductor device manufacturing process and the like, and a pattern forming method using the same.

Along with the large integration of semiconductor integrated circuits and the downsizing of semiconductor elements, it is desired to accelerate the development of lithography technology. At present, as exposure light, pattern formation is performed by optical lithography using a mercury lamp, KrF excimer laser, ArF excimer laser, etc., and the use of an F ₂ laser having a shorter wavelength of 157 nm is also considered. However, since many problems still remain in the exposure apparatus and the resist material, the practical use of photolithography using exposure light with a shorter wavelength is still ahead.

Under such circumstances, an immersion lithography method has recently been proposed in order to further refine the pattern using conventional exposure light (see Non-Patent Document 1).

  According to this immersion lithography method, the area between the projection lens and the resist film on the wafer in the exposure apparatus is filled with a liquid having a refractive index of n, so the NA (numerical aperture) of the exposure apparatus. Since the value of n becomes n · NA, the resolution of the resist film is improved.

  Hereinafter, a pattern forming method using conventional immersion lithography will be described with reference to FIGS. 20 (a) to 20 (d).

  First, a positive chemically amplified resist material having the following composition is prepared.

Poly ((norbornene-5-methylene-t-butylcarboxylate) (50mol%)-(maleic anhydride) (50mol%)) (base polymer) ………………………………………… ……… 2g
Triphenylsulfonium triflate (acid generator) …………………… 0.06g
Triethanolamine (quencher) ………………………………… 0.002g
Propylene glycol monomethyl ether acetate (solvent) ……………… 20g
Next, as shown in FIG. 20A, the chemically amplified resist material is applied onto the substrate 1 to form a resist film 2 having a thickness of 0.35 μm.

  Next, as shown in FIG. 20B, an immersion liquid (water) 3 is arranged on the resist film 2, and the exposure light 4 made of an ArF excimer laser with NA of 0.68 is masked. The resist film 2 is irradiated through 5 to perform pattern exposure.

Next, as shown in FIG. 20C, the resist film 2 subjected to pattern exposure is heated for 60 seconds at a temperature of 105 ° C. with a hot plate, and then tetramethyl with a concentration of 2.38 wt%. When development is performed with an aqueous ammonium hydroxide solution (alkaline developer), as shown in FIG. 20 (d), a resist pattern 2a consisting of an unexposed portion of the resist film 2 and having a line width of 0.09 μm can be obtained.
M. Switkes and M. Rothschild, "Immersion lithography at 157 nm", J. Vac. Sci. Technol., Vol. B19, P. 2353 (2001)

  However, as shown in FIG. 20 (d), the pattern shape of the resist pattern 2a obtained by the conventional pattern forming method is poor.

  The inventors of the present application have obtained the following conclusions as a result of various investigations on the cause of the defective shape of the resist pattern obtained by immersion lithography. That is, a low molecular weight compound such as an acid generator or a quencher elutes from the resist film 2 in the liquid 3 disposed on the resist film 2 or the liquid 3 penetrates into the resist film 2. The desired performance cannot be obtained in the resist itself. For example, in the case shown in FIG. 20D, since the concentration of acid from the acid generator is reduced at the interface between the exposed area and the unexposed area in the resist film 2, the upper portion of the resist pattern 2a has a bowl-shaped defective pattern. It is thought that it became. Conversely, when the concentration of the quencher that deactivates the acid is lowered, the resulting resist pattern 2a has a defective shape in which the upper end is rounded.

  In any case, if etching is performed on the film to be processed using the resist pattern 2a having a defective shape, the shape of the pattern obtained from the film to be processed also becomes defective. There arises a problem that the performance and the yield are lowered.

  In view of the above-described conventional problems, the present invention is to prevent the influence of a liquid for immersion exposure technology used in immersion lithography on a resist film and to obtain a fine pattern having a good shape. Objective.

  Based on the results of the above-mentioned studies, the inventors of the present invention formed a barrier film on the resist film, so that the resist film and the liquid disposed on the resist film are not in direct contact with each other. It has been found that it is possible to prevent these components from eluting into the liquid and preventing the liquid from penetrating into the resist film.

  The present invention is made on the basis of the above knowledge, and forms a barrier film on the resist film that prevents the components in the resist film from eluting into the liquid or permeating the liquid into the resist film. By forming the film, the intended performance of the resist film is maintained. Specifically, this is realized by the following method.

  The barrier film forming material according to the present invention is for forming a barrier film between a resist film and a liquid when a liquid is disposed on the resist film made of a chemically amplified resist and the resist film is exposed. Targeting a barrier film forming material, the barrier film is characterized by preventing components in the resist film from eluting into the liquid or preventing the liquid from penetrating into the resist film.

  According to the barrier film forming material of the present invention, in immersion lithography in which a liquid is disposed on a resist film made of a chemically amplified resist and the resist film is exposed, the barrier film forming material is provided between the resist film and the liquid. The barrier film formed by using the resist film prevents the resist film from eluting into the liquid, for example, components such as an acid generator and a quencher, or penetrating the liquid into the resist film. The expected performance of the chemically amplified resist is maintained. As a result, a resist pattern having a good shape can be obtained.

  The present inventors have found that when a polymer having a sulfonamide structure is used as the material for forming the barrier film, the barrier film containing the polymer having the sulfonamide structure can prevent contact between the liquid and the resist film. Have gained.

  A polymer having a sulfonamide structure is soluble in a solution having a hydrogen ion index (pH) value greater than 7, and is hardly soluble in a neutral or acidic solution. Therefore, it is usually not soluble in a neutral or acidic liquid having a pH value of 7 or less, but is soluble in an alkaline aqueous solution that is a developer, and thus can be easily removed after exposure.

  The barrier film according to the present invention preferably contains a polymer having a sulfonamide structure.

  In this case, polyvinyl sulfonamide or a polyvinyl sulfonamide derivative can be used for the polymer. As the polyvinylsulfonamide derivative, polyvinylsulfone alkylamide, polyvinylsulfone fluorinated alkylamide, or polyvinylsulfone substituted alkylamide can be used.

  Moreover, a hydroxyl group, an alkoxy group, an oxo group, an amino group, or an alkylamino group can be used as the substituent in the polyvinylsulfone substituted alkylamide.

  A first pattern forming method using a material for forming a barrier film according to the present invention includes a step of forming a resist film made of a chemically amplified resist on a substrate, and a step of forming a barrier film on the resist film. The pattern exposure is performed by selectively irradiating the resist film with exposure light through the barrier film in a state where the liquid is disposed on the barrier film, and the pattern exposure is performed after the barrier film is removed. The resist film is developed to form a resist pattern from the resist film, and the barrier film has the components in the resist film elute into the liquid or the liquid penetrates into the resist film. It is characterized by preventing.

  According to the first pattern forming method, a resist film is subjected to pattern exposure through a barrier film in a state where a barrier film is formed on the resist film and a liquid is disposed on the formed barrier film. Since this barrier film prevents the components in the resist film from eluting into the liquid or the liquid from penetrating into the resist film, the resist film maintains the expected performance of the chemically amplified resist during exposure. . As a result, a resist pattern having a good shape can be obtained from the resist film. Here, the removal of the barrier film before development may be performed using an aqueous solution having a pH value at which the barrier film dissolves, and examples thereof include a developer or a diluted developer. The degree of dilution of the diluted developer is only required to be lower than that of a normal alkaline developer (2.38 wt% tetramethylammonium hydroxide). For example, a concentration of 0.001 wt% to 2 wt% can be used. However, the present invention is not limited to this concentration range.

  A second pattern forming method according to the present invention includes a step of forming a resist film made of a chemically amplified resist on a substrate, a step of forming a barrier film on the resist film, and a liquid on the barrier film. In this state, pattern exposure is performed by selectively irradiating the resist film with exposure light through the barrier film, and the resist film subjected to pattern exposure is developed to remove the barrier film. And a step of forming a resist pattern from the resist film, and the barrier film is characterized in that the components in the resist film are prevented from eluting into the liquid or the liquid is prevented from penetrating into the resist film.

  According to the second pattern forming method, similarly to the first pattern forming method, the barrier film is formed on the resist film, and the pattern exposure of the resist film is performed with the liquid disposed on the formed barrier film. To do. Since this barrier film prevents the components in the resist film from eluting into the liquid or the liquid from penetrating into the resist film, the resist film maintains the expected performance of the chemically amplified resist during exposure. As a result, a resist pattern having a good shape can be obtained from the resist film.

  By the way, the difference between the first pattern forming method and the second pattern forming method is that, in the first pattern forming method, the barrier film on the resist film is removed before development, while the second pattern forming method is different from the second pattern forming method. In this pattern forming method, the barrier film on the resist film is removed by a developing solution during development. In the case of the first pattern formation method, since the barrier film is removed before development, the development process proceeds as usual. Further, in the case of the second pattern forming method, since the barrier film is removed during development, the dissolution characteristics of the resist can be controlled, and as a result, the dissolution characteristics of the resist are improved. The control of dissolution characteristics will be described later.

  The first or second pattern forming method preferably further includes a step of performing a heat treatment on the formed barrier film before the step of performing pattern exposure. In this way, by heating the formed barrier film, the denseness of the barrier film is improved and the poor solubility in the liquid is increased. Note that if the density of the barrier film is excessively improved, it is difficult to dissolve and remove the barrier film, and thus it is necessary to heat in an appropriate temperature range. For example, an appropriate temperature range for heating is about 100 ° C. to 150 ° C. although it depends on the composition of the barrier film. However, the present invention is not limited to this temperature range.

  In the first or second pattern formation method, the barrier film preferably contains a polymer having a sulfonamide structure. Here, the specific composition of the polymer having a sulfonamide structure may be the compound shown in the barrier film forming material of the present invention.

  In the first or second pattern formation method, water or perfluoropolyether can be used as the liquid. The liquid may contain an additive such as a surfactant.

  In the first or second pattern formation method, an acidic solution can be used as the liquid for the immersion exposure technique. For example, the acidic solution includes an aqueous phosphoric acid solution or an aqueous cesium sulfate solution. However, the present invention is not limited to these acidic solutions.

In the first or second pattern forming method, KrF excimer laser light, ArF excimer laser light, F ₂ laser light, ArKr laser light, or Ar ₂ laser light can be used as the exposure light.

  According to the barrier film forming material or the pattern forming method using the same according to the present invention, by forming the barrier film using the barrier film forming material between the resist film and the liquid for immersion exposure technology, Since the influence of the immersion liquid on the resist film is prevented, a miniaturized pattern having a good shape can be obtained.

(First reference example)
A pattern forming method using a barrier film forming material according to a first reference example of the present invention will be described with reference to FIGS. 1 (a) to 1 (d), 2 (a), and 2 (b). .

  First, a positive chemically amplified resist material having the following composition is prepared.

Poly ((norbornene-5-methylene-t-butylcarboxylate) (50mol%)-(maleic anhydride) (50mol%)) (base polymer) ………………………………………… ……… 2g
Triphenylsulfonium triflate (acid generator) …………………… 0.06g
Triethanolamine (quencher) ………………………………… 0.002g
Propylene glycol monomethyl ether acetate (solvent) ……………… 20g
Next, as shown in FIG. 1A, the chemically amplified resist material is applied onto the substrate 101 to form a resist film 102 having a thickness of 0.35 μm.

  Next, as shown in FIG. 1B, a barrier film forming material having the following composition is formed on the resist film 102 by a spin coating method, for example, with a thickness of 0.06 μm and a pH value. Barrier films 103 having different solubility are formed.

Polyvinyl alcohol (alkali-soluble polymer) ... 1g
1,1-di (perfluoromethyl) -2-perfluoroethylethenyloxybenzyltrimethylammonium (fluorine surfactant) ……………………………………… 0.0003 g
Isobutyl alcohol (solvent) …………………………………………………… 20g
Next, as shown in FIG. 1C, an immersion liquid 104 made of water is disposed between the barrier film 103 and the projection lens 106 by, for example, a paddle (liquid accumulation) method, and NA is 0. The resist film 102 is irradiated with the exposure light 105 which is ArF excimer laser light of .68 and transmitted through a mask (not shown) through the barrier film 103 to perform pattern exposure.

  Next, as shown in FIG. 1D, the resist film 102 subjected to pattern exposure is heated with a hot plate at a temperature of 105 ° C. for 60 seconds (post-exposure baking).

  Next, as shown in FIG. 2A, for example, the barrier film 103 is removed with a tetramethylammonium hydroxide aqueous solution (alkaline diluted developer) having a concentration of 0.01 wt%, and then the baked resist film 102 is formed. On the other hand, when development is performed with a 2.38 wt% tetramethylammonium hydroxide aqueous solution (alkaline developer), as shown in FIG. A resist pattern 102a having a good shape with a line width can be obtained.

  As described above, according to the first reference example, the barrier film 103 containing the alkali-soluble polymer and the fluorosurfactant is formed on the resist film 102 before the pattern exposure shown in FIG. Therefore, the resist film 102 is not in direct contact with the liquid 104 for immersion. As a result, components in the resist film 102 such as an acid generator or quencher are eluted into the immersion liquid 104, or conversely, the immersion liquid 104 penetrates into the resist film 102. Therefore, the resist film 102 maintains the expected performance of the chemically amplified resist during exposure and subsequent post-exposure baking. As a result, the resist pattern 102a obtained from the resist film 102 does not deteriorate in shape.

(Second reference example)
Hereinafter, a pattern forming method using the barrier film forming material according to the second reference example of the present invention will be described with reference to FIGS. 3 (a) to 3 (d) and FIGS. 4 (a) to 4 (c). explain.

  First, a positive chemically amplified resist material having the following composition is prepared.

Poly ((norbornene-5-methylene-t-butylcarboxylate) (50mol%)-(maleic anhydride) (50mol%)) (base polymer) ………………………………………… ……… 2g
Triphenylsulfonium triflate (acid generator) …………………… 0.06g
Triethanolamine (quencher) ………………………………… 0.002g
Propylene glycol monomethyl ether acetate (solvent) ……………… 20g
Next, as shown in FIG. 3A, the chemically amplified resist material is applied onto the substrate 201 to form a resist film 202 having a thickness of 0.35 μm.

  Next, as shown in FIG. 3B, a thickness of 0.07 μm is formed on the resist film 202 from the barrier film forming material having the following composition by a spin coating method, for example, depending on the pH value. Barrier films 203 having different solubility are formed.

Polyvinyl pyrrolidone (alkali-soluble polymer) ... 1g
1,1-di (perfluoroisopropyl) -2-perfluoromethylethenyloxybenzyltrimethylammonium (fluorine surfactant) ………………………… 0.0005 g
n-Butyl alcohol (solvent) …………………………………………………… 20g
Next, as shown in FIG. 3C, the formed barrier film 203 is heated by a hot plate at a temperature of 120 ° C. for 90 seconds to improve the denseness of the barrier film 203.

  Next, as shown in FIG. 3D, an immersion liquid 204 made of water is disposed between the heat-treated barrier film 203 and the projection lens 206, for example, by a paddle (liquid accumulation) method. The resist film 202 is irradiated with the exposure light 205, which is ArF excimer laser light having an NA of 0.68 and transmitted through a mask (not shown), through the barrier film 203 to perform pattern exposure.

  Next, as shown in FIG. 4A, the resist film 202 that has been subjected to pattern exposure is heated by a hot plate at a temperature of 105 ° C. for 60 seconds (post exposure bake).

  Next, as shown in FIG. 4B, for example, the barrier film 203 is removed with a tetramethylammonium hydroxide aqueous solution (alkaline diluted developer) having a concentration of 0.005 wt%, and then the baked resist film 202 is formed. On the other hand, when the development is performed with a 2.38 wt% tetramethylammonium hydroxide aqueous solution (alkaline developer), as shown in FIG. A resist pattern 202a having a good shape with a line width can be obtained.

  As described above, according to the second reference example, the barrier film 203 containing the alkali-soluble polymer and the fluorosurfactant is formed on the resist film 202 before the pattern exposure shown in FIG. Therefore, the resist film 202 does not come into direct contact with the immersion liquid 204. As a result, components in the resist film 202 such as an acid generator or a quencher are eluted into the immersion liquid 204, or conversely, the immersion liquid 204 penetrates into the resist film 202. Therefore, the resist film 202 maintains the expected performance of the chemically amplified resist during exposure and subsequent post-exposure baking. As a result, the resist pattern 202a obtained from the resist film 202 does not deteriorate in shape.

  In addition, in the second reference example, as shown in FIG. 3C, the barrier film 203 is heated to improve its density before pattern exposure, thereby improving the density of the barrier film 203. The insolubility with respect to the liquid (water) 204 for immersion is increased. For this reason, it is possible to improve the function of the barrier film 203 itself as a barrier that prevents the acid generator and the like from being eluted from the resist film 202 into the immersion liquid 204.

(Third reference example)
Hereinafter, a pattern forming method using a barrier film forming material according to a third reference example of the present invention will be described with reference to FIGS. 5 (a) to 5 (d) and FIG.

  First, a positive chemically amplified resist material having the following composition is prepared.

Poly ((norbornene-5-methylene-t-butylcarboxylate) (50mol%)-(maleic anhydride) (50mol%)) (base polymer) ………………………………………… ……… 2g
Triphenylsulfonium triflate (acid generator) …………………… 0.06g
Triethanolamine (quencher) ………………………………… 0.002g
Propylene glycol monomethyl ether acetate (solvent) ……………… 20g
Next, as shown in FIG. 5A, the chemically amplified resist material is applied on the substrate 301 to form a resist film 302 having a thickness of 0.35 μm.

  Next, as shown in FIG. 5B, a barrier film forming material having the following composition is formed on the resist film 302 by a spin coating method, for example, with a thickness of 0.05 μm and a pH value. A barrier film 303 having different solubility is formed.

Polyacrylic acid (alkali-soluble polymer) ... 1g
1,1-di (perfluoromethyl) -2-perfluoroethylethenyl polyoxyethylene ether (fluorine surfactant) …………………………………………………… 0 .0006g
n-Butyl alcohol (solvent) …………………………………………………… 20g
Next, as shown in FIG. 5C, an immersion liquid 304 made of water is disposed between the barrier film 303 and the projection lens 306 by, for example, a paddle (liquid accumulation) method, and NA is 0. The resist film 302 is irradiated with the exposure light 305, which is ArF excimer laser light of .68, which has passed through a mask (not shown), through the barrier film 303 to perform pattern exposure.

  Next, as shown in FIG. 5D, the resist film 302 subjected to pattern exposure is heated with a hot plate at a temperature of 105 ° C. for 60 seconds (post-exposure baking).

  Next, when the barrier film 303 is removed from the baked resist film 302 with a 2.38 wt% tetramethylammonium hydroxide aqueous solution (alkaline developer) and further developed, as shown in FIG. Thus, a resist pattern 302a having an excellent shape with a line width of 0.09 μm, which is made of an unexposed portion of the resist film 302, can be obtained.

  As described above, according to the third reference example, the barrier film 303 containing the alkali-soluble polymer and the fluorosurfactant is formed on the resist film 302 before the pattern exposure shown in FIG. Therefore, the resist film 302 is not in direct contact with the immersion liquid 304. As a result, components in the resist film 302 such as an acid generator or quencher are eluted into the immersion liquid 304, or conversely, the immersion liquid 304 penetrates into the resist film 302. Therefore, the resist film 302 maintains the expected performance of the chemically amplified resist during exposure and subsequent post-exposure baking. As a result, the resist pattern 302a obtained from the resist film 302 does not deteriorate in shape.

  Incidentally, unlike the first and second reference examples, the pattern forming method according to the third reference example removes the barrier film 303 during development, that is, with an alkaline developer. In this way, the dissolution characteristics of the resist film 302 can be controlled. Hereinafter, control of dissolution characteristics will be described with reference to the drawings.

  In general, as shown in the graph A shown by the broken line in FIG. 7, in the graph in which the dissolution property of the resist by the developer is excellent, the dissolution rate rapidly increases when the exposure amount exceeds a certain threshold value. As the change in the dissolution rate with respect to the exposure amount becomes steeper, the difference in solubility between the exposed portion and the unexposed portion in the resist film 302 becomes larger. Can do. Accordingly, when the barrier film 303 is simultaneously removed during development as shown by the solid line B in the figure, the dissolution rate decreases as a whole while the barrier film 303 is removed. The amount of change in the portion surrounded by C can be reduced to approximate the flat graph A. As a result, when the dissolution characteristics of the actual resist are as shown in graph B, the dissolution rate when the exposure amount is small is relatively constant at a low dissolution rate even with a small exposure amount and a certain range. It can adjust so that it may become a melt | dissolution state. Accordingly, the difference in solubility between the exposed portion and the unexposed portion in the resist film 302 is substantially increased, so that a resist pattern having a good shape can be easily obtained.

(Fourth reference example)
Hereinafter, a pattern forming method using a barrier film forming material according to a fourth reference example of the present invention will be described with reference to FIGS. 8 (a) to 8 (d), 9 (a), and 9 (b). explain.

  First, a positive chemically amplified resist material having the following composition is prepared.

Poly ((norbornene-5-methylene-t-butylcarboxylate) (50mol%)-(maleic anhydride) (50mol%)) (base polymer) ………………………………………… ……… 2g
Triphenylsulfonium triflate (acid generator) …………………… 0.06g
Triethanolamine (quencher) ………………………………… 0.002g
Propylene glycol monomethyl ether acetate (solvent) ……………… 20g
Next, as shown in FIG. 8A, the chemically amplified resist material is applied on a substrate 401 to form a resist film 402 having a thickness of 0.35 μm.

  Next, as shown in FIG. 8B, a thickness of 0.04 μm is formed on the resist film 402 from the barrier film forming material having the following composition by a spin coating method, for example, depending on the pH value. Barrier films 403 having different solubility are formed.

Polyvinyl hexafluoroisopropyl alcohol (alkali-soluble polymer) ………………………………………………………………………………………………………… ... 1g
1,1-di (perfluoroisopropyl) -2-perfluoromethylethenyl polyoxyethylene ether (fluorine surfactant) …………………………………………… 0.0005 g
Isobutyl alcohol (solvent) …………………………………………………… 20g
Next, as shown in FIG. 8C, the formed barrier film 403 is heated with a hot plate at a temperature of 115 ° C. for 90 seconds to improve the denseness of the barrier film 403.

  Next, as shown in FIG. 8D, an immersion liquid 404 made of water is disposed between the heat-treated barrier film 403 and the projection lens 406 by, for example, a paddle (liquid accumulation) method. Pattern exposure is performed by irradiating the resist film 402 with exposure light 405 that is ArF excimer laser light having NA of 0.68 and transmitted through a mask (not shown).

  Next, as shown in FIG. 9A, the resist film 402 subjected to pattern exposure is heated with a hot plate at a temperature of 105 ° C. for 60 seconds (post-exposure baking).

  Next, when the barrier film 403 is removed and further developed with a 2.38 wt% tetramethylammonium hydroxide aqueous solution (alkaline developer) with respect to the baked resist film 402, FIG. 9B shows. As shown, a resist pattern 402a having a good shape with a line width of 0.09 [mu] m can be obtained.

  As described above, according to the fourth reference example, the barrier film 403 containing the alkali-soluble polymer and the fluorosurfactant is formed on the resist film 402 before the pattern exposure shown in FIG. Therefore, the resist film 402 is not in direct contact with the liquid 404 for immersion. As a result, components in the resist film 402 such as an acid generator or quencher are eluted into the immersion liquid 404, or conversely, the immersion liquid 404 permeates into the resist film 402. Therefore, the resist film 402 maintains the expected performance of the chemically amplified resist during exposure and subsequent post-exposure baking. As a result, the resist pattern 402a obtained from the resist film 402 does not deteriorate in shape.

  In addition, in the fourth reference example, as shown in FIG. 8C, the barrier film 403 formed is heated before pattern exposure to improve the denseness of the barrier film 403. The insolubility with respect to the liquid (water) 404 for immersion is increased. Therefore, it is possible to improve the function of the barrier film 403 itself that prevents elution of the acid generator or the like from the resist film 402 into the immersion liquid 404 as a barrier.

  Further, similarly to the third reference example, since the barrier film 403 is removed during development, that is, with an alkaline developer, the dissolution characteristics of the resist film 402 can be controlled.

(Fifth reference example)
Hereinafter, a pattern forming method using a barrier film forming material according to a fifth reference example of the present invention will be described with reference to FIGS. 10 (a) to 10 (d), FIG. 11 (a), and FIG. 11 (b). explain.

  First, a positive chemically amplified resist material having the following composition is prepared.

Poly (styrene hexafluoroisopropyl alcohol) (40mol%)-(α-trifluoromethyl-t-butyl acrylate) (60mol%)) ……………………………………………… 2g
Triphenylsulfonium triflate (acid generator) …………………… 0.06g
Triethanolamine (quencher) ………………………………… 0.003g
Propylene glycol monomethyl ether acetate (solvent) ……………… 20g
Next, as shown in FIG. 10A, the chemically amplified resist material is applied onto the substrate 501 to form a resist film 502 having a thickness of 0.15 μm.

  Next, as shown in FIG. 10B, a thickness of 0.03 μm and a pH value is applied from a barrier film forming material having the following composition on the resist film 502 by, for example, spin coating. Barrier films 503 having different solubility are formed.

Polyvinyl alcohol (alkali-soluble polymer) ... 1g
1,1-di (perfluoromethyl) -2-perfluoroethylethenyloxybenzyltrimethylammonium (fluorine surfactant) ……………………………………… 0.0003 g
Isoamyl alcohol (solvent) …………………………………………………… 20g
Next, as shown in FIG. 10C, an immersion liquid 504 made of perfluoropolyether is disposed between the barrier film 503 and the projection lens 506 by, for example, a paddle (liquid accumulation) method, Pattern exposure is performed by irradiating the resist film 502 with exposure light 505 that is F ₂ laser light having NA of 0.85 and transmitted through a mask (not shown) through the barrier film 503.

  Next, as shown in FIG. 10D, the resist film 502 subjected to pattern exposure is heated with a hot plate at a temperature of 110 ° C. for 60 seconds (post-exposure baking).

  Next, as shown in FIG. 11A, for example, the barrier film 503 is removed with a tetramethylammonium hydroxide aqueous solution (alkaline diluted developer) having a concentration of 0.01 wt%, and then the baked resist film 502 is formed. On the other hand, when the development is performed with a 2.38 wt% tetramethylammonium hydroxide aqueous solution (alkaline developer), as shown in FIG. A resist pattern 502a having a good shape with a line width can be obtained.

  As described above, according to the fifth reference example, the barrier film 503 containing the alkali-soluble polymer and the fluorosurfactant is formed on the resist film 502 before the pattern exposure shown in FIG. Therefore, the resist film 502 does not come into direct contact with the immersion liquid 504. As a result, components in the resist film 502 such as an acid generator or quencher are eluted into the immersion liquid 504, or conversely, the immersion liquid 504 penetrates into the resist film 502. Therefore, the resist film 502 maintains the expected performance of the chemically amplified resist during exposure and subsequent post-exposure baking. As a result, the resist pattern 502a obtained from the resist film 502 does not deteriorate in shape.

  Also in the fifth reference example, heat treatment for improving the denseness of the deposited barrier film 503 may be performed before pattern exposure.

  Further, as in the third and fourth reference examples, the barrier film 503 may be removed at the time of development instead of being removed before development.

  In each of the first to fifth reference examples, polyvinyl hexafluoroisopropyl alcohol, polyvinyl alcohol, polyvinyl pyrrolidone, polyacrylic acid, and polystyrene sulfonic acid were used as the alkali-soluble polymer constituting each barrier film. However, besides this, hydroxyethyl cellulose, polyisoprene sulfonic acid or pullulan can be used.

  Further, the fluorosurfactant added to each barrier film is not limited to the surfactant used in each of the first to fifth reference examples, and is an interface having a group containing a double bond, such as a perfluoroalkenyl group. An activator can be used.

(Sixth embodiment)
A pattern forming method using a barrier film forming material according to a sixth embodiment of the present invention will be described with reference to FIGS. 12 (a) to 12 (d), FIG. 13 (a), and FIG. 13 (b). .

  First, a positive chemically amplified resist material having the following composition is prepared.

Poly ((norbornene-5-methylene-t-butylcarboxylate) (50mol%)-(maleic anhydride) (50mol%)) (base polymer) ………………………………………… ……… 2g
Triphenylsulfonium triflate (acid generator) …………………… 0.06g
Triethanolamine (quencher) ………………………………… 0.002g
Propylene glycol monomethyl ether acetate (solvent) ……………… 20g
Next, as shown in FIG. 12A, the chemically amplified resist material is applied on a substrate 601 to form a resist film 602 having a thickness of 0.35 μm.

  Next, as shown in FIG. 12B, a thickness of 0.07 μm is formed on the resist film 602 from the barrier film forming material having the following composition by a spin coating method, for example, depending on the pH value. Barrier films 603 having different solubility are formed.

Polyvinylsulfonamide (Polymer) ……………………………………………… 1g
Isopropyl alcohol (solvent) ……………………………………………………… 20g
Next, as shown in FIG. 12C, an immersion liquid 604 made of water is disposed between the barrier film 603 and the projection lens 606 by, for example, a paddle (liquid accumulation) method, and NA is 0. The resist film 602 is irradiated with the exposure light 605 that is ArF excimer laser light of .68 and transmitted through a mask (not shown) to perform pattern exposure.

  Next, as shown in FIG. 12D, the resist film 602 that has been subjected to pattern exposure is heated by a hot plate at a temperature of 105 ° C. for 60 seconds (post-exposure baking).

  Next, as shown in FIG. 13A, for example, the barrier film 603 is removed with a tetramethylammonium hydroxide aqueous solution (alkaline diluted developer) having a concentration of 0.01 wt%, and then the baked resist film 602 is formed. On the other hand, when the development is performed with a 2.38 wt% tetramethylammonium hydroxide aqueous solution (alkaline developer), as shown in FIG. A resist pattern 602a having a good shape with a line width can be obtained.

  Thus, according to the sixth embodiment, before the pattern exposure shown in FIG. 12C, the barrier film 603 containing a polymer having a sulfonamide structure (polyvinylsulfonamide) is formed on the resist film 602. Since the film is formed, the resist film 102 is not in direct contact with the liquid 104 for immersion. As a result, components in the resist film 602 such as an acid generator or a quencher are eluted into the immersion liquid 604, or conversely, the immersion liquid 604 penetrates into the resist film 602. Therefore, the resist film 602 maintains the expected performance of the chemically amplified resist during exposure and subsequent post-exposure bake. As a result, the resist pattern 602a obtained from the resist film 602 does not deteriorate in shape.

(Seventh embodiment)
Hereinafter, a pattern forming method using a barrier film forming material according to the seventh embodiment of the present invention will be described with reference to FIGS. 14 (a) to 14 (d) and FIGS. 15 (a) to 15 (c). explain.

  First, a positive chemically amplified resist material having the following composition is prepared.

Poly ((norbornene-5-methylene-t-butylcarboxylate) (50mol%)-(maleic anhydride) (50mol%)) (base polymer) ………………………………………… ……… 2g
Triphenylsulfonium triflate (acid generator) …………………… 0.06g
Triethanolamine (quencher) ………………………………… 0.002g
Propylene glycol monomethyl ether acetate (solvent) ……………… 20g
Next, as shown in FIG. 14A, the chemically amplified resist material is applied on a substrate 701 to form a resist film 702 having a thickness of 0.35 μm.

  Next, as shown in FIG. 14B, a thickness of 0.06 μm is formed on the resist film 702 from the barrier film forming material having the following composition by a spin coating method, for example, depending on the pH value. Barrier films 703 having different solubility are formed.

Polyvinylsulfone-N-ethylamide (polymer) …………………… 1g
n-Butyl alcohol (solvent) …………………………………………………… 20g
Next, as shown in FIG. 14C, the formed barrier film 703 is heated by a hot plate at a temperature of 120 ° C. for 90 seconds to improve the denseness of the barrier film 703.

  Next, as shown in FIG. 14D, an immersion liquid 704 made of water is disposed between the heat-treated barrier film 703 and the projection lens 706 by, for example, a paddle (liquid accumulation) method. Pattern exposure is performed by irradiating the resist film 702 with exposure light 705 that is ArF excimer laser light having an NA of 0.68 and transmitted through a mask (not shown) through the barrier film 703.

  Next, as shown in FIG. 15A, the resist film 702 that has been subjected to pattern exposure is heated by a hot plate at a temperature of 105 ° C. for 60 seconds (post-exposure baking).

  Next, as shown in FIG. 15B, for example, the barrier film 703 is removed with a tetramethylammonium hydroxide aqueous solution (alkaline diluted developer) having a concentration of 0.005 wt%, and then the baked resist film 702 is formed. On the other hand, when the development is performed with a 2.38 wt% tetramethylammonium hydroxide aqueous solution (alkaline developer), as shown in FIG. A resist pattern 702a having a favorable line width can be obtained.

  Thus, according to the seventh embodiment, before the pattern exposure shown in FIG. 14D, a barrier containing a polymer (polyvinylsulfone-N-ethylamide) having a sulfonamide structure on the resist film 702 is provided. Since the film 703 is formed, the resist film 702 is not in direct contact with the immersion liquid 704. As a result, the components in the resist film 702, such as an acid generator or quencher, are eluted into the immersion liquid 704, or conversely, the immersion liquid 704 penetrates into the resist film 702. Therefore, the resist film 702 maintains the expected performance of the chemically amplified resist during exposure and subsequent post-exposure baking. As a result, the resist pattern 702a obtained from the resist film 702 does not deteriorate in shape.

  In addition, in the seventh embodiment, as shown in FIG. 14C, the barrier film 703 is heated to improve the denseness before pattern exposure, thereby improving the density of the barrier film 703. The insolubility of the liquid (water) 704 for immersion is increased. For this reason, the function of the barrier film 703 itself that prevents elution of the acid generator or the like from the resist film 702 into the immersion liquid 704 can be improved.

(Eighth embodiment)
A pattern forming method using the barrier film forming material according to the eighth embodiment of the present invention will be described below with reference to FIGS. 16 (a) to 16 (d) and FIG.

  First, a positive chemically amplified resist material having the following composition is prepared.

Poly ((norbornene-5-methylene-t-butylcarboxylate) (50mol%)-(maleic anhydride) (50mol%)) (base polymer) ………………………………………… ……… 2g
Triphenylsulfonium triflate (acid generator) …………………… 0.06g
Triethanolamine (quencher) ………………………………… 0.002g
Propylene glycol monomethyl ether acetate (solvent) ……………… 20g
Next, as shown in FIG. 16A, the chemically amplified resist material is applied on a substrate 801 to form a resist film 802 having a thickness of 0.35 μm.

  Next, as shown in FIG. 16B, a thickness of 0.07 μm is formed on the resist film 802 from the barrier film forming material having the following composition by, for example, spin coating, depending on the pH value. Barrier films 803 having different solubility are formed.

Polyvinylsulfone-N-chloromethylamide (polymer) …………………… 1g
Isopropyl alcohol (solvent) ……………………………………………………… 20g
Next, as shown in FIG. 16C, an immersion liquid 804 made of water is disposed between the barrier film 803 and the projection lens 806 by, for example, a paddle (liquid accumulation) method so that NA is 0. The resist film 802 is irradiated with the exposure light 805 which is ArF excimer laser light of .68 and transmitted through a mask (not shown) to perform pattern exposure.

  Next, as shown in FIG. 16D, the resist film 802 subjected to pattern exposure is heated with a hot plate at a temperature of 105 ° C. for 60 seconds (post-exposure baking).

  Next, when the barrier film 803 is removed from the baked resist film 802 with a 2.38 wt% tetramethylammonium hydroxide aqueous solution (alkaline developer) and further developed, as shown in FIG. Thus, a resist pattern 802a made of an unexposed portion of the resist film 802 and having a good shape with a line width of 0.09 μm can be obtained.

  Thus, according to the eighth embodiment, a polymer having a sulfonamide structure (polyvinylsulfone-N-chloromethylamide) is formed on the resist film 802 before the pattern exposure shown in FIG. Since the barrier film 803 is formed, the resist film 802 is not in direct contact with the immersion liquid 804. As a result, components in the resist film 802, such as an acid generator or quencher, are eluted into the immersion liquid 804, or conversely, the immersion liquid 804 penetrates into the resist film 802. Therefore, the resist film 802 maintains the expected performance of the chemically amplified resist during exposure and subsequent post-exposure baking. As a result, the resist pattern 802a obtained from the resist film 802 does not deteriorate in shape.

  Further, similarly to the third reference example, since the barrier film 803 is removed during development, that is, with an alkaline developer, the dissolution characteristics of the resist film 802 can be controlled.

(Ninth embodiment)
Hereinafter, a pattern forming method using a barrier film forming material according to the ninth embodiment of the present invention will be described with reference to FIGS. 18 (a) to 18 (d), 19 (a), and 19 (b). explain.

  First, a positive chemically amplified resist material having the following composition is prepared.

Poly ((norbornene-5-methylene-t-butylcarboxylate) (50mol%)-(maleic anhydride) (50mol%)) (base polymer) ………………………………………… ……… 2g
Triphenylsulfonium triflate (acid generator) …………………… 0.06g
Triethanolamine (quencher) ………………………………… 0.002g
Propylene glycol monomethyl ether acetate (solvent) ……………… 20g
Next, as shown in FIG. 18A, the chemically amplified resist material is applied on a substrate 901 to form a resist film 902 having a thickness of 0.35 μm.

  Next, as shown in FIG. 18B, a thickness of 0.08 μm is formed on the resist film 902 from the barrier film forming material having the following composition by a spin coating method, for example, depending on the pH value. Barrier films 903 having different solubility are formed.

Polyvinylsulfone-N-hydroxyethylamide (polymer) ……………… 1g
n-Amyl alcohol (solvent) …………………………………………………… 20g
Next, as shown in FIG. 18C, the formed barrier film 903 is heated by a hot plate at a temperature of 115 ° C. for 90 seconds to improve the denseness of the barrier film 903.

  Next, as shown in FIG. 18 (d), an immersion liquid 904 made of water is disposed between the heat-treated barrier film 903 and the projection lens 906, for example, by a paddle (liquid accumulation) method. Pattern exposure is performed by irradiating the resist film 902 with exposure light 905 that is ArF excimer laser light with NA of 0.68 and transmitted through a mask (not shown) through the barrier film 903.

  Next, as shown in FIG. 19A, the resist film 902 subjected to pattern exposure is heated with a hot plate at a temperature of 105 ° C. for 60 seconds (post-exposure baking).

  Next, when the barrier film 903 is removed from the baked resist film 902 with a 2.38 wt% tetramethylammonium hydroxide aqueous solution (alkaline developer) and further developed, the result shown in FIG. As shown, a resist pattern 902a having a good shape with a line width of 0.09 μm can be obtained.

  Thus, according to the ninth embodiment, a polymer having a sulfonamide structure (polyvinylsulfone-N-hydroxyethylamide) is formed on the resist film 402 before the pattern exposure shown in FIG. Since the barrier film 903 is formed, the resist film 902 is not in direct contact with the liquid 904 for immersion. As a result, components in the resist film 902, such as an acid generator or quencher, are eluted into the immersion liquid 904, or conversely, the immersion liquid 904 penetrates into the resist film 902. Therefore, the resist film 902 maintains the expected performance of the chemically amplified resist during exposure and subsequent post-exposure baking. As a result, the resist pattern 902a obtained from the resist film 902 does not deteriorate in shape.

  Further, similarly to the third reference example, since the barrier film 903 is removed during development, that is, with an alkaline developer, the dissolution characteristics of the resist film 902 can be controlled.

In each of the first to fourth reference examples and each of the sixth to ninth embodiments, ArF excimer laser light is used as exposure light, and in the fifth reference example, F ₂ laser light is used as exposure light. However, the present invention is not limited thereto, and KrF excimer laser light, ArKr laser light, or Ar ₂ laser light can be used as exposure light.

In each of the first to fifth reference examples and the sixth to ninth embodiments, for example, cesium sulfate (Cs ₂ SO ₄ ) or phosphoric acid (H ₃ PO ₄ ) is added to the immersion liquid. The refractive index of the immersion liquid may be increased. In this case, the concentration of cesium sulfate or phosphoric acid may be about 1 wt% to 10 wt%. However, the concentration is not necessarily limited to this.

  The film thickness of each barrier film is not limited to the film thickness of about 0.03 μm to 0.08 μm shown in each reference example and each embodiment, and the lower limit value is that the components in the resist film are used for immersion. The film thickness is such that it can be prevented from eluting into the liquid or the immersion liquid penetrating into the resist film, and the upper limit is a film that does not interfere with the transmission of exposure light and can be easily removed. It is thick. For example, the thickness is preferably 0.01 μm to 0.15 μm, and more preferably about 0.02 μm to 0.10 μm. However, it is not necessarily limited to this numerical range.

  In each reference example and each embodiment, the paddle method is used as a method of disposing the immersion liquid on the barrier film. However, the method is not limited to this, and for example, the entire substrate is immersed in the immersion liquid. A dip method or the like may be used.

  In each reference example and each embodiment, a positive chemically amplified resist is used for the resist film. However, the present invention can also be applied to a negative chemically amplified resist.

  The barrier film forming material and the pattern forming method using the same according to the present invention can prevent the influence of the liquid for the immersion exposure technique on the resist film, and can obtain a resist pattern having a good shape. This is useful as a method for forming a fine pattern used in a manufacturing process.

(A)-(d) is sectional drawing which shows each process of the pattern formation method using the material for barrier film formation concerning the 1st reference example of this invention. (A) And (b) is sectional drawing which shows each process of the pattern formation method using the barrier film formation material which concerns on the 1st reference example of this invention. (A)-(d) is sectional drawing which shows each process of the pattern formation method using the barrier film formation material which concerns on the 2nd reference example of this invention. (A)-(c) is sectional drawing which shows each process of the pattern formation method using the barrier film formation material which concerns on the 2nd reference example of this invention. (A)-(d) is sectional drawing which shows each process of the pattern formation method using the material for barrier film formation concerning the 3rd reference example of this invention. It is sectional drawing which shows each process of the pattern formation method using the barrier film formation material which concerns on the 3rd reference example of this invention. It is a graph explaining the control of the solubility of the resist in the pattern formation method using the barrier film formation material which concerns on the 3rd reference example of this invention. (A)-(d) is sectional drawing which shows each process of the pattern formation method using the barrier film formation material which concerns on the 4th reference example of this invention. (A) And (b) is sectional drawing which shows each process of the pattern formation method using the barrier film formation material which concerns on the 4th reference example of this invention. (A)-(d) is sectional drawing which shows each process of the pattern formation method using the material for barrier film formation concerning the 5th reference example of this invention. (A) And (b) is sectional drawing which shows each process of the pattern formation method using the material for barrier film formation concerning the 5th reference example of this invention. (A)-(d) is sectional drawing which shows each process of the pattern formation method using the barrier film formation material which concerns on the 6th Embodiment of this invention. (A) And (b) is sectional drawing which shows each process of the pattern formation method using the barrier film formation material which concerns on the 6th Embodiment of this invention. (A)-(d) is sectional drawing which shows each process of the pattern formation method using the barrier film formation material which concerns on the 7th Embodiment of this invention. (A)-(c) is sectional drawing which shows each process of the pattern formation method using the barrier film formation material which concerns on the 7th Embodiment of this invention. (A)-(d) is sectional drawing which shows each process of the pattern formation method using the barrier film formation material which concerns on the 8th Embodiment of this invention. It is sectional drawing which shows each process of the pattern formation method using the barrier film formation material which concerns on the 8th Embodiment of this invention. (A)-(d) is sectional drawing which shows each process of the pattern formation method using the barrier film formation material which concerns on the 9th Embodiment of this invention. (A) And (b) is sectional drawing which shows each process of the pattern formation method using the barrier film formation material which concerns on the 9th Embodiment of this invention. (A)-(d) is sectional drawing which shows each process of the pattern formation method by the conventional immersion lithography.

Explanation of symbols

101 Substrate 102 Resist Film 102a Resist Pattern 103 Barrier Film 104 Immersion Liquid 105 Exposure Light 106 Projection Lens 201 Substrate 202 Resist Film 202a Resist Pattern 203 Barrier Film 204 Immersion Liquid 205 Exposure Light 206 Projection Lens 301 Substrate 302 Resist Film 302a resist pattern 303 barrier film 304 immersion liquid 305 exposure light 306 projection lens 401 substrate 402 resist film 402a resist pattern 403 barrier film 404 immersion liquid 405 exposure light 406 projection lens 501 substrate 502 resist film 502a resist pattern 503 Barrier film 504 Liquid for immersion 505 Exposure light 506 Projection lens 601 Substrate 602 Resist film 602a Resist pattern 603 Barrier film 604 Liquid for immersion 605 Light 606 Projection lens 701 Substrate 702 Resist film 702a Resist pattern 703 Barrier film 704 Immersion liquid 705 Exposure light 706 Projection lens 801 Substrate 802 Resist film 802a Resist pattern 803 Barrier film 804 Immersion liquid 805 Exposure light 806 Projection Lens 901 Substrate 902 Resist film 902a Resist pattern 903 Barrier film 904 Liquid for immersion 905 Exposure light 906 Projection lens

Claims (10)

When exposing the resist film by arranging a liquid which is water or perfluoropolyether on a resist film made of a chemically amplified resist, a barrier film is formed between the resist film and the liquid. A barrier film forming material,
The said barrier film | membrane contains the polymer which has a sulfonamide structure, The material for barrier film formation characterized by the above-mentioned. The barrier film-forming material according to claim 1, wherein the polymer is polyvinylsulfonamide or a polyvinylsulfonamide derivative.   The barrier film-forming material according to claim 2, wherein the polyvinylsulfonamide derivative is polyvinylsulfone alkylamide, polyvinylsulfone fluorinated alkylamide, or polyvinylsulfone-substituted alkylamide.   The material for forming a barrier film according to claim 3, wherein the substituent in the polyvinylsulfone-substituted alkylamide is a hydroxyl group, an alkoxy group, an oxo group, an amino group, or an alkylamino group. Forming a resist film made of a chemically amplified resist on a substrate; forming a barrier film on the resist film;
A step of performing pattern exposure by selectively irradiating the resist film with exposure light through the barrier film in a state where a liquid that is water or perfluoropolyether is disposed on the barrier film;
Developing the resist film subjected to pattern exposure, and removing the barrier film and forming a resist pattern from the resist film,
The pattern forming method, wherein the barrier film includes a polymer having a sulfonamide structure. The pattern forming method according to claim 5, wherein the polymer is polyvinylsulfonamide or a polyvinylsulfonamide derivative.   The pattern forming method according to claim 6, wherein the polyvinylsulfonamide derivative is polyvinylsulfone alkylamide, polyvinylsulfone fluorinated alkylamide, or polyvinylsulfone-substituted alkylamide.   The pattern forming method according to claim 7, wherein the substituent in the polyvinylsulfone-substituted alkylamide is a hydroxyl group, an alkoxy group, an oxo group, an amino group, or an alkylamino group.   The pattern forming method according to claim 5, wherein phosphoric acid or cesium sulfate is added to the water. The pattern forming method according to claim 5, wherein the exposure light is KrF excimer laser light, ArF excimer laser light, F ₂ laser light, ArKr laser light, or Ar ₂ laser light.

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