JP2010251802A - Semiconductor manufacturing apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To make the shape of a resist pattern, obtained by immersion lithography, excellent. <P>SOLUTION: A semiconductor manufacturing apparatus includes a movable stage 31 for holding a wafer 20, an exposure section 30 for carrying out pattern exposure in a state wherein liquid is arranged between a resist film formed on the wafer 20 and an exposure lens 32, a liquid supply section 33 for supplying the liquid 25 onto the resist film, and a liquid discharge section 34 for discharging the liquid 25 arranged on the resist film through the resist film. Further, the semiconductor manufacturing apparatus includes a temperature control section 60 configured to control the temperature of the movable stage 31 to be lower than the temperature of the liquid 25. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a semiconductor manufacturing apparatus used in a semiconductor device manufacturing process or the like.

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, a KrF excimer laser, an ArF excimer laser, or the like, and the use of an F ₂ laser having a shorter wavelength is also being studied. However, since many problems still remain in the exposure apparatus and the resist material, the time for practical application of photolithography using exposure light having a shorter wavelength is still ahead.

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

  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 (where n> 1), and therefore the NA of the exposure apparatus. Since the value of (numerical aperture) is 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. 6 (a) to 6 (d).

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

Poly ((tertiary butyl = norbornene-5-methylenecarboxylate) (50mol%)-(maleic anhydride) (50mol%)) (base polymer) ………………………………………… ……… 2g
Triphenylsulfonium nonaflate (acid generator) …………………… 0.06g
Triethanolamine (quencher) ………………………………… 0.002g
Propylene glycol monomethyl ether acetate (solvent) ……………… 20g
Next, as shown in FIG. 6A, 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. 6B, a liquid (water) 3 having a temperature of room temperature, for example, about 23 ° C. is disposed between the resist film 2 and the projection lens 5 so that the NA is 0.68. Pattern exposure is performed by irradiating the resist film 2 with exposure light 4 made of an ArF excimer laser through a mask.

  Next, as shown in FIG. 6C, the resist film 2 subjected to pattern exposure is heated for 60 seconds at a temperature of 105 ° C. by a hot plate, and then tetramethylammonium having a concentration of 0.26N. When development is performed with a hydroxide developer, a resist pattern 2 a having a line width of 0.09 μm, which is formed of an unexposed portion of the resist film 2, is obtained as shown in FIG.

M. Switkes and M. Rothschild, "Immersion lithography at 157 nm", J. Vac. Sci. Technol., Vol. B19, P. 2353 (2001)

  However, as shown in FIG. 6 (d), the pattern shape of the resist pattern 2a obtained by the pattern forming method using the conventional immersion lithography is poor.

  The inventors of the present application have conducted various studies on the cause of the defective shape of the resist pattern obtained by immersion lithography, and as a result, the liquid 3 for immersion and the projection lens 5 are evaporated by evaporation during exposure. A gap was formed between the two and the refractive index of the liquid 3 fluctuated by this gap, and a predetermined resolution could not be obtained.

  Therefore, the resist pattern shape becomes defective due to the exposure performed through the immersion liquid in which a part of the liquid is evaporated, and when etching is performed using the resist pattern having a defective shape, the pattern obtained in the film to be etched This also causes a problem that the productivity and yield in the manufacturing process of the semiconductor device are reduced.

  In view of the above-described conventional problems, an object of the present invention is to improve the shape of a resist pattern obtained by immersion lithography.

  In order to achieve the above object, according to the present invention, a pattern forming method using immersion lithography uses a liquid having a composition that does not easily evaporate into an immersion liquid, or evaporates the immersion liquid during exposure. The configuration is arranged in an environment that is difficult to perform. In addition, the semiconductor manufacturing apparatus is configured to perform pattern exposure in an environment in which liquid for immersion is difficult to evaporate during exposure.

  Specifically, the first pattern forming method according to the present invention includes a step of forming a resist film on a substrate, and a liquid containing an unsaturated fatty acid on the resist film. The method includes a step of performing pattern exposure by selectively irradiating exposure light and a step of developing the resist film on which pattern exposure has been performed to form a resist pattern.

  According to the first pattern forming method, since the liquid containing the unsaturated fatty acid is used as the liquid for immersion, the liquid for immersion becomes difficult to evaporate due to the added unsaturated fatty acid. As a result, the liquid for immersion is prevented from anomalies in refractive index due to the voids generated by evaporation during exposure, so that a predetermined refractive index (exposure characteristics) is maintained in the liquid during exposure. The shape of the resist pattern can be improved.

  The present inventors have found that unsaturated fatty acids have a high moisturizing action due to their high lipids. This moisturizing action is due to a function derived from a double bond or triple bond between carbons of an unsaturated fatty acid and a function derived from a carboxylic acid group. The double bond or triple bond between carbons is in a state in which electrons are concentrated particularly between carbon atoms in a molecule connected by a single bond. Moreover, since the double bond of carbon and oxygen which a carboxylic acid group has is a double bond between oxygen whose electronegativity is higher than carbon, an electron is more than in the case of a double bond between carbons. Since it attracts a lot, it is in a highly ionic state. As a result, an interaction is likely to occur even with a molecule or substituent having a low ionicity, and particularly an interaction with a hydroxyl group contained in the immersion liquid is easily caused. As a result, the unsaturated fatty acid exhibits a high moisturizing action and can suppress evaporation of the liquid for immersion.

  The unsaturated fatty acid preferably has a structure in which a double bond or triple bond between carbons and a carbonyl group derived from a carboxylic acid group occupy relatively close positions. In the case of having a structure indicating a close position, as shown in [Chemical Formula 1] below, it becomes possible to share abundant electrons between the bonds of each other, so that a more ionic state is obtained. Since it is stabilized, the moisturizing effect is enhanced.

本発明に係る第２のパターン形成方法は、基板の上にレジスト膜を形成する工程と、レジスト膜の上に液体を配した状態で、レジスト膜に対して露光光を選択的に照射することによりパターン露光を行なう工程と、パターン露光が行なわれたレジスト膜に対して現像を行なってレジストパターンを形成する工程とを備え、パターン露光を行なう工程において、露光雰囲気の温度は液体の温度よりも低いことを特徴とする。

The second pattern forming method according to the present invention includes a step of forming a resist film on a substrate, and selectively irradiating the resist film with exposure light in a state where a liquid is disposed on the resist film. And a step of developing the resist film subjected to pattern exposure to form a resist pattern, wherein the exposure atmosphere temperature is higher than the liquid temperature. It is characterized by being low.

  According to the second pattern forming method, since the exposure atmosphere temperature is lower than the liquid temperature in the pattern exposure step, the saturated vapor pressure (maximum vapor pressure) of the exposure atmosphere is reduced. Becomes difficult to evaporate. As a result, a refractive index abnormality caused by evaporation of the immersion liquid during exposure is prevented and a predetermined refractive index is maintained, so that the resist pattern shape by immersion lithography can be improved. .

  According to a third pattern forming method of the present invention, a resist film is formed on a substrate, and exposure light is selected for the resist film in a state where a liquid is disposed on the resist film and the substrate is cooled. And a step of performing pattern exposure by irradiating the pattern and a step of developing the resist film on which pattern exposure has been performed to form a resist pattern.

  According to the third pattern forming method, since the liquid is disposed on the resist film and the pattern exposure is performed in a state where the substrate is cooled, the cooled liquid is difficult to evaporate. This prevents an abnormality in the refractive index due to evaporation of the immersion liquid during exposure, and maintains a predetermined refractive index in the immersion liquid during exposure. The shape of the resist pattern can be improved.

In the first pattern formation method, oleic acid (CH ₃ — (CH ₂ ) ₇ —CH═CH— (CH ₂ ) ₇ —COOH) can be used as the unsaturated fatty acid.

  In this case, olive oil, safflower oil, sunflower oil or canola oil can be used as oleic acid. Here, the range of 0.01 wt% or more and 5 wt% or less can be applied as the amount of unsaturated fatty acid added to the liquid, but it is not necessarily limited to this concentration range.

  In the second pattern forming method, the temperature of the exposure atmosphere is preferably higher than 0 ° C. and lower than 23 ° C.

  In the third pattern forming method, the temperature of the cooled substrate is preferably lower than the exposure atmosphere.

  In this case, the temperature of the exposure atmosphere is preferably higher than 0 ° C. and lower than 23 ° C.

  In the first to third pattern forming methods, water or perfluoropolyether can be used as the immersion liquid.

Further, in the first to third pattern forming methods, an additive can be added to the immersion liquid. For example, when cesium sulfate (CsSO ₄ ) or ethyl alcohol (C ₂ H ₅ OH) is used as an additive for increasing the refractive index of the liquid, the additive added to the liquid evaporates or volatilizes. The present invention is extremely effective because there is a risk that the exposure characteristics will be adversely affected as a change in refractive index.

  A first conductor manufacturing apparatus according to the present invention includes an exposure unit that performs liquid pattern exposure by arranging a liquid between a resist film and an exposure lens, a liquid supply unit that supplies liquid onto the resist film, and a resist film. A liquid discharging unit for discharging the liquid disposed on the resist film from above the resist film, a temperature measuring unit for measuring the temperature of the liquid and the atmospheric temperature of the exposure unit, an air conditioning unit for adjusting the atmospheric temperature, and a temperature measuring unit And a temperature control unit that controls the air conditioning unit so that the atmospheric temperature is lower than the temperature of the liquid based on the temperature of the liquid and the atmospheric temperature measured by the above.

  According to the first semiconductor manufacturing apparatus, the air conditioning unit that adjusts the ambient temperature, and the air conditioning unit is configured so that the ambient temperature is lower than the liquid temperature based on the liquid temperature and the ambient temperature measured by the temperature measuring unit. Since the saturated vapor pressure in the exposure atmosphere is reduced because the temperature control unit is controlled, it is difficult for the liquid for immersion to evaporate. As a result, abnormalities in the refractive index due to evaporation of the immersion liquid during exposure are prevented, and the predetermined refractive index is maintained in the liquid, so that the resist pattern shape by immersion lithography is improved. can do.

  In the first semiconductor manufacturing apparatus, it is preferable that the exposure unit and the air conditioning unit are provided inside one chamber.

  A second conductor manufacturing apparatus according to the present invention includes a wafer holding unit that holds a wafer, an exposure unit that performs pattern exposure by placing a liquid between a resist film formed on the wafer and an exposure lens, and a resist A liquid supply unit that supplies liquid onto the film, a liquid discharge unit that discharges the liquid disposed on the resist film from above the resist film, and a temperature measurement that measures the temperature of the liquid and the temperature of the wafer holding unit And a cooling unit for cooling the wafer holding unit.

  According to the second semiconductor manufacturing apparatus, since the cooling unit for cooling the wafer holding unit is provided, the immersion liquid is cooled through the wafer holding unit cooled by the cooling unit. Becomes difficult to evaporate. As a result, an abnormality in the refractive index caused by evaporation of the immersion liquid during exposure can be prevented. As a result, the immersion liquid during exposure can maintain a predetermined refractive index. The shape of the pattern can be improved.

  The second semiconductor manufacturing apparatus preferably further includes a temperature control unit that controls the temperature of the cooling unit based on the temperature of the liquid measured by the temperature measuring unit and the temperature of the wafer holding unit.

  In the first or second semiconductor manufacturing apparatus, water or perfluoropolyether can be used as the immersion liquid.

In the first to third pattern forming methods or the first to second semiconductor manufacturing apparatuses, the exposure light source includes KrF excimer laser light, Xe ₂ laser light, ArF excimer laser light, F ₂ laser light, and KrAr laser. Light or Ar ₂ laser light can be used.

  According to the semiconductor manufacturing apparatus and the pattern forming method according to the present invention, it is possible to suppress the evaporation of the immersion liquid disposed on the resist film and to prevent an abnormal exposure due to the evaporation of the liquid. A resist pattern can be obtained.

(A)-(d) is sectional drawing which shows each process of the pattern formation method which concerns on the 1st Embodiment of this invention. It is typical sectional drawing which shows the principal part of the semiconductor manufacturing apparatus which concerns on the 2nd Embodiment of this invention. (A)-(d) is sectional drawing which shows each process of the pattern formation method which concerns on the 2nd Embodiment of this invention. It is typical sectional drawing which shows the principal part of the semiconductor manufacturing apparatus which concerns on the 3rd Embodiment of this invention. (A)-(d) is sectional drawing which shows each process of the pattern formation method which concerns on the 3rd Embodiment of this invention. (A)-(d) is sectional drawing which shows each process of the conventional pattern formation method.

(First embodiment)
A pattern forming method according to a first embodiment of the present invention will be described with reference to FIGS. 1 (a) to 1 (d).

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

Poly ((tertiary butyl = norbornene-5-methylenecarboxylate) (50mol%)-(maleic anhydride) (50mol%)) (base polymer) ………………………………………… ……… 2g
Triphenylsulfonium nonaflate (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 on the wafer 101 to form a resist film 102 having a thickness of 0.35 μm.

  Next, as shown in FIG. 1B, a liquid 103 to which sunflower oil containing oleic acid, which is an unsaturated fatty acid, is added at a concentration of 1 wt% is disposed between the resist film 102 and the projection lens 105. In this state, pattern exposure is performed by irradiating the resist film 102 with exposure light 104 made of an ArF excimer laser having a numerical aperture NA of 0.68 through a mask (not shown). Here, the temperature of the liquid 103 is room temperature, for example, about 23 ° C.

  Next, as shown in FIG. 1C, the resist film 102 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 ammonium hydroxide developer, as shown in FIG. 1 (d), a resist pattern 102a having a line width of 0.09 μm and having a good shape is formed of the unexposed portion of the resist film 102. can get.

  Thus, according to the pattern formation method according to the first embodiment, sunflower oil containing oleic acid, which is an unsaturated fatty acid, is added to the liquid 103 for immersion. Since 103 becomes difficult to evaporate, no gap is generated in the liquid 103 disposed between the resist film 102 and the projection lens 105. As a result, an abnormality in refractive index due to voids does not occur in the liquid 103, so that the liquid 103 can maintain predetermined exposure characteristics, and as a result, the resist pattern shape by immersion lithography can be improved. Can do.

In addition to sunflower oil, olive oil, safflower oil, canola oil, etc. can be used for oleic acid which is an unsaturated fatty acid. Here, the amount of unsaturated fatty acid added to the liquid 103 may be 0.01 wt% or more and 5 wt% or less, but is not necessarily limited to this concentration range.
(Second Embodiment)
Hereinafter, a semiconductor manufacturing apparatus and a pattern forming method using the same according to a second embodiment of the present invention will be described with reference to the drawings.

  FIG. 2 schematically shows a configuration of a main part of a semiconductor manufacturing apparatus according to the second embodiment of the present invention. As shown in FIG. 2, the semiconductor manufacturing apparatus 10 </ b> A according to the second embodiment includes an exposure unit 30 that exposes a predetermined design pattern on the resist film inside the chamber 11, and air conditioning that adjusts the temperature in the chamber 11. For example, a temperature monitor 50 that measures the temperature of the immersion liquid and the temperature of the exposure atmosphere of the exposure unit 40 is provided.

  Outside the chamber 11, a temperature control unit 60 that controls the air conditioning unit 40 based on the temperature of the exposure unit 30 sent from the temperature monitor 50, that is, the temperature of the atmosphere in the chamber 11 and the temperature of the liquid 25 for immersion. Is provided.

  The exposure unit 30 includes a movable stage 31 that holds the wafer 20 on which a resist film (not shown) is formed on the upper surface, and a projection lens (exposure lens) 32 that is positioned above the wafer 20 held on the movable stage 31. A liquid supply unit 33 that supplies the immersion liquid 25 between the resist film and the projection lens 32, and a liquid discharge unit 34 that discharges the liquid 25 from above the resist film after exposure. In FIG. 2, an illumination optical system including a light source for exposure light and a mask (reticle) having a desired design pattern, which are normally disposed above the projection lens 32, are omitted.

  The temperature monitor 50 includes a first measurement point 51 that measures the temperature of the exposure atmosphere in the exposure unit 30 and a second measurement point 52 that measures the temperature of the liquid 25 disposed between the wafer 20 and the projection lens 32. And the temperature data measured are transmitted to the temperature control unit 60.

  Based on the received temperature data, the temperature control unit 60 determines that the temperature of the exposure atmosphere from the first measurement point 51 (the temperature in the chamber 11) is that of the liquid 25 for immersion from the second measurement point 52. When the temperature is higher than the temperature, the operation state of the air conditioning unit 40 is controlled so that the temperature in the chamber 11 is lower than the temperature of the liquid 25.

  Thus, according to the semiconductor manufacturing apparatus 10A according to the second embodiment, the temperature of the exposure atmosphere in the chamber 11 can be controlled to be lower than the temperature of the immersion liquid 25 during exposure. In addition, it is preferable that the atmospheric temperature at this time is higher than 0 degreeC, and is 23 degrees C or less.

  Therefore, if the temperature of the exposure atmosphere is lower than the temperature of the liquid 25, the saturated vapor pressure of the liquid 25 decreases and the liquid 25 can be cooled indirectly, so that the liquid 25 is prevented from evaporating during exposure. In other words, no gap is generated in the liquid 25 disposed between the wafer 20 and the projection lens 32. As a result, the liquid 25 does not have an abnormality in the refractive index due to the gap, and the predetermined exposure characteristics can be maintained with respect to the liquid 25 for immersion.

  Moreover, since the air conditioning unit 40 and the temperature monitor 50 adjust the temperature in the chamber 11 in conjunction with each other via the temperature control unit 60, it is possible to prevent the temperature of the immersion liquid 25 from fluctuating greatly during the exposure process. it can. As a result, the refractive index variation due to the temperature change in the liquid 25 can also be suppressed, so that variations in exposure accuracy that occur between a plurality of shots can be reduced. Here, the exposure shot is that the main surface of the wafer 20 is usually divided into a plurality of exposure areas, and exposure light is sequentially irradiated to each of the divided exposure areas. Exposure of exposure light to one exposure region at this time is called one shot.

  In the second embodiment, the second measurement point 52 is set to the immersion liquid 25 disposed between the resist film and the projection lens 32, but the temperature in the vicinity of the liquid 25, that is, The ambient temperature of the liquid 25 may be measured.

  Similarly to the first embodiment, when an unsaturated fatty acid made of oleic acid or the like is added to the liquid 25, the evaporation of the liquid 25 can be further suppressed.

(Pattern formation method)
Hereinafter, a pattern forming method using the exposure apparatus configured as described above will be described with reference to FIGS. 3 (a) to 3 (d).

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

Poly ((tertiary butyl = norbornene-5-methylenecarboxylate) (50mol%)-(maleic anhydride) (50mol%)) (base polymer) ………………………………………… ……… 2g
Triphenylsulfonium nonaflate (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 wafer 20 to form a resist film 21 having a thickness of 0.35 μm.

  Next, the wafer 20 on which the resist film 21 is formed is held on the movable stage 31 of the exposure unit 30 in the semiconductor manufacturing apparatus 10A shown in FIG. 2, and then the temperature is 23 as shown in FIG. A liquid 25 having a room temperature of about 0 ° C. is disposed between the resist film 21 and the projection lens 32. At this time, based on the temperature data of the liquid 25 from the second measurement point 52, the temperature control unit 60 shown in FIG. 2 has the temperature of the exposure atmosphere, that is, the temperature data from the first measurement point 51 becomes 15 ° C. Thus, the air conditioning unit 40 is controlled. In this state, pattern exposure is performed by irradiating the resist film 21 with exposure light 35 made of an ArF excimer laser having a numerical aperture NA of 0.68 through a mask (not shown).

  Next, as shown in FIG. 3C, the resist film 21 that has been subjected to pattern exposure is heated on a hot plate at a temperature of 105 ° C. for 60 seconds, and then has a concentration of 2.38 wt% tetramethyl. When development is performed with an ammonium hydroxide developer, as shown in FIG. 3D, a resist pattern 21a having a line width of 0.09 .mu.m and having a good shape is formed from the unexposed portion of the resist film 21. can get.

  As described above, according to the pattern forming method according to the second embodiment, the temperature in the chamber 11, that is, the temperature of the exposure atmosphere is set lower than the temperature of the immersion liquid 25 during exposure. Since it is difficult to evaporate, no gap is generated in the liquid 25 disposed between the resist film 21 and the projection lens 32. As a result, the liquid 25 is free from abnormal refractive index due to voids and the like, so that the liquid 25 can maintain predetermined exposure characteristics, and the shape of the resist pattern 21a obtained by immersion lithography can be improved. it can.

(Third embodiment)
Hereinafter, a semiconductor manufacturing apparatus and a pattern forming method using the same according to a third embodiment of the present invention will be described with reference to the drawings.

  FIG. 4 schematically shows a configuration of a main part of a semiconductor manufacturing apparatus according to the third embodiment of the present invention. In FIG. 4, the same components as those shown in FIG. As shown in FIG. 4, in the semiconductor manufacturing apparatus 10 </ b> B according to the third embodiment, a cooling unit 36 that can cool the movable stage 31 is provided below the movable stage 31 in the exposure unit 30 in the chamber 11. It is characterized by.

  The temperature monitor 50 measures the temperature of the liquid 25 disposed between the first measurement point 53 for measuring the temperature of the liquid 25 in the liquid supply unit 33 of the exposure unit 30 and the projection lens 32. The temperature is measured with respect to the two measurement points 54, and the measured temperature data is transmitted to the temperature control unit 60.

  The temperature control unit 60 according to the third embodiment is provided in the chamber 11, and the temperature of the liquid 25 in the liquid supply unit 33 sent from the temperature monitor 50 and the liquid 25 arranged on the wafer 20. Based on the temperature, the temperature of the cooling unit 36 is controlled. The temperature control unit 60 may be installed inside the chamber 11 or may be installed outside.

  Based on the received temperature data, the temperature control unit 60 has the temperature of the liquid 25 for immersion from the second measurement point 54 higher than the temperature of the liquid 25 before being supplied from the first measurement point 53. In this case, the cooling unit 36 is cooled so that the temperature of the liquid 25 disposed on the wafer 20 is equal to or lower than the temperature of the liquid 25 before supply. Accordingly, the liquid 25 disposed on the wafer 20 is indirectly cooled via the movable stage 31 by the cooled cooling unit 36.

  As a specific configuration example of the cooling unit 8, at least one refrigerant pipe capable of circulating the refrigerant is disposed below the movable stage 31. Thus, by circulating the coolant below the movable stage 31, the liquid 25 can be indirectly cooled through the movable stage 31, the wafer 20, and the resist film.

  Thus, according to the semiconductor manufacturing apparatus 10B according to the third embodiment, during exposure, the immersion liquid 25 disposed on the wafer 20 receives light energy from the exposure light and liquid from the liquid supply unit 33. A temperature rise caused by receiving kinetic energy when moving to the discharge unit 34 can be suppressed.

  Therefore, since the temperature of the immersion liquid 25 disposed on the wafer 20 can be controlled as appropriate, evaporation of the liquid 25 disposed on the wafer 20 during exposure can be suppressed. Moreover, since the temperature monitor 50 and the cooling unit 36 adjust the temperature of the liquid 25 in conjunction with each other via the temperature control unit 60, the temperature of the liquid 25 can be prevented from greatly fluctuating during the exposure process. As a result, the refractive index variation due to the temperature change in the liquid 25 can also be suppressed, so that variations in exposure accuracy that occur between a plurality of shots can be reduced.

  In the third embodiment, the second measurement point 54 is set to the liquid 25 for immersion disposed between the resist film and the projection lens 32. However, the temperature in the vicinity of the liquid 25, that is, the liquid 25 ambient temperatures may be measured.

  Similarly to the first embodiment, when an unsaturated fatty acid made of oleic acid or the like is added to the liquid 25, the evaporation of the liquid 25 can be further suppressed.

  Further, the chamber 11 is not necessarily required in the semiconductor manufacturing apparatus 10B according to the third embodiment.

(Pattern formation method)
Hereinafter, a pattern forming method using the exposure apparatus configured as described above will be described with reference to FIGS. 5 (a) to 5 (d).

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

Poly ((tertiary butyl = norbornene-5-methylenecarboxylate) (50mol%)-(maleic anhydride) (50mol%)) (base polymer) ………………………………………… ……… 2g
Triphenylsulfonium nonaflate (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 onto the wafer 20 to form a resist film 21 having a thickness of 0.35 μm.

  Next, the wafer 20 on which the resist film 21 is formed is held on the movable stage 31 of the exposure unit 30 in the semiconductor manufacturing apparatus 10B shown in FIG. 4, and then the temperature is 23 from the liquid supply unit 33 shown in FIG. A liquid 25 having a room temperature of about 0 ° C. is disposed between the resist film 21 and the projection lens 32 as shown in FIG. At this time, the temperature control unit 60 shown in FIG. 4 has a temperature of the movable stage 31 of 13 ° C. with respect to the cooling unit 36 based on the temperature data of the liquid 25 on the resist film 21 sent from the second measurement point 54. Control to be. In this state, pattern exposure is performed by irradiating the resist film 21 with exposure light 35 made of an ArF excimer laser having a numerical aperture NA of 0.68 through a mask (not shown).

  Next, as shown in FIG. 5C, the resist film 21 that has been subjected to pattern exposure is heated on a hot plate at a temperature of 105 ° C. for 60 seconds, and then a tetramethyl having a concentration of 2.38 wt%. When development is performed with an ammonium hydroxide developer, as shown in FIG. 5D, a resist pattern 21a having a line width of 0.09 .mu.m and having a good shape is formed of the unexposed portion of the resist film 21. can get.

  As described above, according to the pattern forming method according to the third embodiment, the temperature of the movable stage 31 is set lower than the temperature of the liquid 25 for immersion at the time of exposure. No gap is generated in the liquid 25 disposed between the resist film 21 and the projection lens 32. As a result, the liquid 25 does not cause an abnormality in the refractive index due to the air gaps, so that predetermined exposure characteristics are maintained in the liquid 25, and the shape of the resist pattern 21a obtained by immersion lithography is improved. be able to.

  In the first to third embodiments, water is used as the liquid for immersion, but perfluoropolyether can be used in addition to water.

In the first to third embodiments, the light source for pattern exposure is not limited to ArF excimer laser light, but KrF excimer laser light, F ₂ laser light, Xe ₂ laser light, Ar ₂ laser light, or ArKr laser light. Can be used.

  In the first to third embodiments, the resist film to be exposed for pattern exposure is not limited to a positive type resist, but may be a negative type resist, or a chemically amplified resist. It goes without saying that it cannot be done.

  Since the semiconductor manufacturing apparatus according to the present invention can prevent the immersion liquid disposed on the resist film from evaporating during the exposure, the resist pattern having a good shape can be prevented due to evaporation. And is useful for forming fine patterns used in semiconductor device manufacturing processes and the like.

10A Semiconductor manufacturing apparatus 10B Semiconductor manufacturing apparatus 11 Chamber 20 Wafer (substrate)
21 resist film 21a resist pattern 25 liquid 30 exposure unit 31 movable stage 32 projection lens (exposure lens)
33 Liquid supply unit 34 Liquid discharge unit 35 Exposure light 36 Cooling unit 40 Air conditioning unit 50 Temperature monitor 51 First measurement point 52 Second measurement point 53 First measurement point 54 Second measurement point 60 Temperature control unit 101 Wafer 102 resist film 102a resist pattern 103 liquid (unsaturated fatty acid added)
104 Exposure light 105 Projection lens (exposure lens)

Claims (8)

A wafer holder for holding the wafer;
An exposure unit that performs pattern exposure by disposing a liquid between a resist film formed on the wafer and an exposure lens;
A liquid supply unit for supplying the liquid onto the resist film;
A liquid discharger for discharging the liquid disposed on the resist film from above the resist film;
A semiconductor manufacturing apparatus comprising: a temperature control unit that controls the temperature of the wafer holding unit to be lower than the temperature of the liquid. A temperature measuring unit for measuring the temperature of the liquid and the temperature of the wafer holding unit;
The semiconductor manufacturing method according to claim 1, wherein the temperature control unit controls the temperature of the wafer holding unit based on the temperature of the liquid measured by the temperature measuring unit and the temperature of the wafer holding unit. apparatus. A wafer holder for holding the wafer;
An exposure unit that performs pattern exposure by disposing a liquid between a resist film formed on the wafer and an exposure lens;
A liquid supply unit for supplying the liquid onto the resist film;
A liquid discharger for discharging the liquid disposed on the resist film from above the resist film;
A semiconductor manufacturing apparatus, comprising: a temperature control unit that controls the temperature of the wafer holding unit to be lower than a temperature in the vicinity of the liquid. A temperature measuring unit for measuring a temperature in the vicinity of the liquid and a temperature of the wafer holding unit;
The temperature control unit controls the temperature of the wafer holding unit based on the temperature in the vicinity of the liquid measured by the temperature measuring unit and the temperature of the wafer holding unit. Semiconductor manufacturing equipment.   The semiconductor manufacturing apparatus according to claim 1, wherein the liquid is water or perfluoropolyether. The light source of the exposure unit is KrF excimer laser light, Xe ₂ laser light, ArF excimer laser light, F ₂ laser light, KrAr laser light, or Ar ₂ laser light. Semiconductor manufacturing equipment.   The semiconductor manufacturing apparatus according to claim 1, wherein the wafer holding unit is a movable stage. The wafer holding part has a cooling part,
The semiconductor manufacturing apparatus according to claim 1, wherein the temperature control unit controls the temperature of the wafer holding unit by controlling the temperature of the cooling unit.

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