JP3878577B2 - Manufacturing method of semiconductor device - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention provides a semiconductor device for processing a resin film pattern using OH radicals and / or O radicals generated by photoexcitation. On the way Related.
[0002]
[Prior art]
In recent years, in the microfabrication technology, it is required to form a device pattern with a very small dimension of less than 50 nm, while processing with very high accuracy is required. In the photolithography used for these processes, KrF → ArF → F ₂ As the wavelength of excimer laser used for exposure is shortened, miniaturization is being promoted. However, even if pattern formation is performed using these excimer lasers, it is not sufficient for the demand for miniaturization, and a size larger than the target is formed by photolithography, and dry etching and UV light irradiation are performed. However, a slimming process for thinning the resist pattern by a dry process such as ashing with ozone (Patent Document 1) is performed.
[0003]
The slimming treatment includes a method using radical molecules / atoms such as OH radicals and O radicals. The problem of this slimming process will be described with reference to FIG.
[0004]
As shown in FIG. 15A, the substrate 101 on which the resist pattern 102 is formed is placed in an atmosphere containing pure water or hydrogen peroxide vapor. Next, the substrate to be processed 101 is irradiated with light, and radical molecules / atoms are generated by photoexcitation. When the resist pattern 102 is reacted with radical molecules / atoms, a reaction product 103 having a large number of alcoholic OH groups in the skeleton of the reaction product is generated. For this reason, a softening point becomes low and fluidity | liquidity becomes high. The substrate is heated by the light applied to the substrate. As shown in FIG. 15B, the reaction product 103 having high fluidity flows due to heat. As a result, as shown in FIG. 15C, the cross-sectional shape of the resist pattern 102 does not become rectangular. Further, the film thickness of the resist pattern 102 is greatly reduced.
[0005]
Moreover, the following problems occur when radical molecules / atoms formed by photoexcitation are used for the modification (oxidation) treatment of the resin insulating film. When the resin film has a pattern, the reaction product flows, so that the modification (oxidation) treatment of the resin film cannot be performed uniformly. In addition, when processing is performed on the resin film formed on the entire surface of the wafer, there is a problem that the resin film flows and uniform processing cannot be performed.
[0006]
[Patent Document 1]
JP 2001-85407 A
[0007]
[Problems to be solved by the invention]
As described above, when a radical molecule / atom such as OH radical or O radical generated by photoexcitation is reacted with a resin film, there is a problem that the reaction product flows and uniform processing cannot be performed. .
[0008]
Further, in the slimming process using radical molecules / atoms such as OH radicals and O radicals generated by photoexcitation, there is a problem that the cross-sectional shape of the pattern does not become rectangular. There is also a problem that the film thickness becomes thin.
[0011]
The purpose of the present invention is to An object of the present invention is to provide a method of manufacturing a semiconductor device capable of suppressing a reduction in the thickness of a resin film when a radical molecule / atom such as OH radical or O radical reacts with a resin film by photoexcitation.
[0012]
[Means for Solving the Problems]
The present invention is configured as follows to achieve the above object.
[0015]
A method of manufacturing a semiconductor device according to an example of the present invention includes a step of forming a resin film pattern on a main surface of a substrate to be processed, Making the main surface of the substrate to be processed face downward; Irradiating the main surface of the substrate to be treated with an atmosphere containing molecules that generate OH radicals and / or O radicals by irradiation with ultraviolet light; and irradiating the main surface of the substrate to be processed with the ultraviolet light. A step of generating OH radicals and / or O radicals from the molecules by the ultraviolet light, and reacting the generated OH radicals and / or O radicals with the resin film to generate a reaction product. To reduce the pattern dimension of the resin film And the resin film upon irradiation with the ultraviolet light Decomposition The method includes a step of heating the substrate to be processed so that the reaction product evaporates at a temperature lower than a temperature, and a step of removing the reaction product after the irradiation with the ultraviolet light.
[0017]
DETAILED DESCRIPTION OF THE INVENTION
Embodiments of the present invention will be described below with reference to the drawings.
[0018]
(First embodiment)
A semiconductor device manufacturing method and a substrate processing apparatus according to a first embodiment of the present invention will be described with reference to FIGS. FIG. 1 is a flowchart showing a method for manufacturing a semiconductor device according to the first embodiment of the present invention. FIG. 2 is a cross-sectional view showing a method for manufacturing a semiconductor device according to the first embodiment of the present invention.
[0019]
First, as shown in FIG. 2A, a 100 nm isolated resist pattern (resin film pattern) 102 is formed on the substrate 101 to be processed (step S101). Note that the substrate to be processed 101 is a wafer in the process of manufacturing a semiconductor device. More specifically, the substrate to be processed 101 is etched using the resist pattern 102 as a mask to form a gate electrode pattern of a MOS transistor.
[0020]
A process for forming the resist pattern 102 will be described below. An antireflection film (film thickness: 50 nm) and a chemically amplified resist (film thickness: 300 nm) are coated on the substrate 101 to be processed, and a gate processing pattern is subjected to reduced projection exposure through an exposure reticle using an ArF excimer laser. The substrate is heat-treated at 120 ° C. for 90 seconds, and then an alkali developer is supplied for 60 seconds to develop the resist film. After a predetermined time has passed, pure water is supplied to stop the reaction and wash it.
[0021]
The wafer 100 having the substrate to be processed 101 and the resist pattern 102 is transferred to the substrate processing apparatus 200 shown in FIG. 3 (step S102). FIG. 3 is a diagram showing the configuration of the substrate processing apparatus according to the first embodiment of the present invention. As shown in FIG. 3, the substrate processing apparatus 200 is provided with a substrate holding unit 202 that holds a target substrate 101 in a chamber 201. The substrate holding means 202 has a cooling function using a Peltier element (or a water cooling function may be used) in order to adjust the temperature of the wafer 100. An irradiation unit 210 is provided. The irradiation unit 210 irradiates the main surface of the wafer 100 with light of 172 nm absorbed by water. The irradiation unit 210 can scan the main surface of the wafer 100 by the moving unit 203.
[0022]
A cleaning liquid supply unit 204 that supplies a cleaning liquid (pure water) to the substrate to be processed is provided in the chamber 201 so as to face the main surface of the wafer 100. Further, a drier 205 that dries the main surface of the wafer 100 is provided facing the main surface of the wafer 100. The cleaning liquid supply unit 204 and the dryer 205 can scan the main surface of the wafer 100 by the moving unit 206.
[0023]
Nitrogen (N ₂ ) Gas, oxygen (O ₂ ) A gas supply device 220 for introducing gas is connected to the chamber 201. In the gas supply device 220, MFCs (mass flow controllers) 221 a to 221 c include a bubbler 222. An exhaust unit 230 that exhausts the inside of the chamber 201 is connected to the chamber via a pipe. Moreover, the MFC control part 223 which controls the flow volume of MFC221a-221c, respectively is provided.
[0024]
The configuration of the irradiation unit 210 will be described with reference to FIG. FIG. 4 is a diagram showing the configuration of the irradiation unit of the substrate processing apparatus shown in FIG. 4A is a front view of the irradiation unit, and FIG. 4B is a cross-sectional view of the irradiation unit. FIG. 4A is a view seen from the scanning direction, and FIG. 4B is a cross-sectional view in a direction orthogonal to the scanning direction.
[0025]
As shown in FIGS. 4A and 4B, a plurality of lamps 212 are arranged in the lamp house 211 along a direction orthogonal to the scanning direction. As the lamp 212, an excimer lamp that emits light having a wavelength of 172 nm was used. A quartz glass (transparent plate) 213 is installed on the side of the lamp house 211 facing the wafer. Power is input to the lamp 212 from the power input unit 215. The power input unit 215 can supply power to each lamp 212 independently and adjust the illuminance of each lamp 212.
[0026]
A reflector 216 is provided in the lamp house 211 in order to irradiate the wafer side with light emitted from the lamp 212 efficiently. In addition, a diffusion plate 217 for reducing unevenness in illuminance is installed between the lamp 212 and the quartz glass 213.
[0027]
A plurality of lamps 212 are used as the lamps in order to increase the illuminance uniformity by adjusting the input power to each lamp. If the lamps are not divided, it is not necessary to use divided lamps. .
[0028]
Next, processing using the substrate processing apparatus shown in FIG. 3 will be described. The wafer 100 is transferred and held by a substrate holding unit 202 of the apparatus 200 from a carrier station (not shown) by a substrate transfer system. After the substrate 100 is mounted on the substrate holding means 202, the atmosphere in the chamber is replaced by the gas supply unit 220 and the exhaust unit 230. Here, the MFC control unit 223 controls the MFCs 221a and 221b to replace the inside of the chamber 201 with an atmosphere of nitrogen and oxygen. The oxygen concentration was set to 1%.
[0029]
Next, the surface of the resist pattern 102 is hydrophilized to increase the contact angle of the resist pattern with water (step S103). Here, the reason why the hydrophilic treatment was performed is that the contact angle of the resist pattern 102 with respect to pure water is 50 °, and it is difficult to form a water adsorption film later. When the hydrophilicity of the resist pattern is high, this hydrophilic treatment is not necessary.
[0030]
The hydrophilic treatment will be described. In the mixed atmosphere of nitrogen and oxygen as described above, the entire surface of the substrate to be processed is irradiated with light of 172 nm from the irradiation unit 210. Ozone is generated from oxygen by irradiation with 172 nm light. The generated ozone and the resist pattern 101 react to make the surface of the resist pattern 102 hydrophilic. After performing the hydrophilic treatment for a predetermined time, the light irradiation from the irradiation unit 210 is stopped.
[0031]
Next, nitrogen gas having a humidity of 80% is supplied from the gas supplier 220 into the chamber 201. The humidity of the mixed gas obtained by mixing the nitrogen gas that has passed through the bubbler 222 in which pure water is stored and the pure nitrogen gas will be described with reference to a humidity meter (not shown). The MFC controller 223 controls the MFCs 221b and 221c according to the measured humidity to change the mixing ratio of the two nitrogen gases. As shown in FIG. 2B, a water adsorption film 112 is formed on the surface of the resist pattern 102 by the water vapor 111 (step S104). At this time, the thickness of the water adsorption film 112 was about several μm.
[0032]
Next, as shown in FIG. 2C, in a state where the adsorption film 112 is formed on the surface of the resist pattern 102, the irradiation unit 210 irradiates the light 120 of 172 nm to perform a slimming process on the resist pattern 102 (step). S105). FIG. 5 is a characteristic diagram showing the wavelength dependence of the water absorption coefficient. As shown in FIG. 5, water has a large absorption coefficient for light of 172 nm. Therefore, radical molecules / atoms 113 of OH radicals and O radicals are generated by photoexcitation from the adsorption film 112 and the water vapor 111 by irradiation with light 172 nm. The radical molecule / atom 113 and the resist pattern 102 react to form a reaction product 103, and the resist pattern 102 is thinned.
[0033]
The irradiation of the light 120 from the irradiation unit 210 was performed by scanning the irradiation unit 210 from one end to the other end on the main surface of the wafer 100 with the lamp 212 turned on as shown in FIG. In the present embodiment, the scanning speed of the irradiation unit 210 is adjusted so that the time during which the light 120 is irradiated (slimming processing time) is 10 seconds.
[0034]
In this embodiment, the output of the lamp 212 is 100 mW / cm. ² The distance between the quartz glass 213 and the substrate to be processed was 20 mm. At this time, the substrate was cooled through the substrate holding unit 202 so that the wafer 100 was 50 ° C. or lower. At this time, the humidity of the atmosphere supplied between the quartz glass and the substrate to be processed is adjusted to be always 80%. The humidity control is intended to prevent drying of the adsorbed water on the resist film surface and to supply moisture to the resist film surface during slimming. The reaction product 103 has an alcoholic property (having an alcoholic OH group), tends to cause a fluid phenomenon due to a low melting point. The wafer 100 is cooled by the substrate holding means 202 so that the reaction product 103 does not flow.
[0035]
After completion of the predetermined slimming process, as shown in FIG. 2D, the cleaning liquid supply unit 204 is scanned over the wafer 100 to supply pure water and clean the wafer 100 (step S106). Further, the drier 205 is scanned on the wafer 100 to remove water droplets remaining on the surface of the wafer 100 (adsorbed water is held on the resist film surface).
[0036]
The slimming rate (speed at which the resist pattern is thinned) obtained by these series of operations was 2 nm / s, and the slimming amount was 20 nm. By these series of treatments, the resist pattern for gate processing which was 100 nm immediately after development was thinned to 80 nm.
[0037]
Further, Step S104 to Step S106 were repeated (Step S105 was 10 seconds), and the resist pattern 102 was thinned to 60 nm. The reason why the processes from Steps S104 to S107 were performed in two steps is that the light of 172 nm used for irradiation attenuates in the reaction product 103, so that no reaction occurs on the surface of the resist pattern 102. In addition, since the reactivity of OH radicals is high, most radicals react on the surface of the resist pattern 102.
[0038]
Since the device using the gate formed by processing the resist pattern 102 formed as described above as a mask can be processed very finely than the gate size used without performing this processing, it can obtain excellent responsiveness. did it.
[0039]
According to the present embodiment, the resist pattern can be thinned efficiently, and a device created using this technology can also obtain excellent responsiveness compared to that produced by the conventional technology.
[0040]
In this embodiment, an excimer lamp light source that irradiates the entire surface of the substrate with light of 172 nm is used for irradiation of light absorbed by water, but the present invention is not limited to this. The light source may be irradiated in a slit shape or a spot shape. It may be changed as needed depending on the required processing uniformity and processing time. In either case, it is necessary to cool the substrate to be processed in the irradiation region. In addition to the excimer lamp, a low pressure mercury lamp or the like may be used as the light source.
[0041]
The film to be processed (resist pattern) is not limited to the above composition. As the resist used in this embodiment, a chemically amplified resist having reactivity with ArF is used, but the resist is not limited to this, and other alicyclic resins (acrylic, coma, hybrid resins) are used. But the same effect was obtained. In addition, any alcoholic OH group can be applied as long as an alcoholic OH group is generated by addition reaction of OH radicals generated by ultraviolet light irradiation. Also effective for resins with aromatic compounds, I-line with novolac resin, G-ray resist, KrF resist composed of resin with polyvinylphenol skeleton, electron beam exposure resist, soft X-ray (EVU) The effect was also confirmed for the resist for exposure. When a resin having an aromatic compound is used, a higher slimming rate can be obtained by using alkaline water such as a TMAH (tetramethylammonium oxide) solution or a KOH solution.
[0042]
If supercritical carbonated water is used for drying, good processing without pattern collapse is possible. The substrate to be processed is transferred to the high-pressure chamber, and the pure water on the main surface of the substrate to be processed after the slimming process is first replaced with alcohol in which carbonic acid is soluble. Furthermore, this alcohol is converted into liquid CO ₂ Replace with. Liquid CO ₂ The drying from the state is 35 ° C., 10 Mpa, and CO in the supercritical state ₂ After changing the state, gradually reduce the chamber pressure to reduce the CO ₂ Vaporize and remove.
[0043]
In this embodiment, when the cleaning is performed with pure water, hydrogen peroxide solution or alcohol after the slimming treatment, the unevenness caused by the condensation of the swelling layer generated during the wet treatment may be seen on the resist pattern surface. . In such a case, the resist pattern surface may be finally irradiated with light of 172 nm in an oxygen or ozone atmosphere. The swelling layer is a so-called reaction intermediate product, and can be selectively peeled off by performing the above-described treatment. As a result, a pattern surface with less unevenness can be formed, and the reliability of the device can be further enhanced.
[0044]
Next, the operation of the present invention will be described. When water is irradiated with light having a wavelength of 200 nm or less, OH radicals and O radicals are generated. OH radicals and O radicals have very strong oxidizing properties, and organic resists are oxidatively decomposed. Therefore, in the state where a liquid film of water is formed on the substrate to be processed, the resist is decomposed by irradiating light and causing OH radicals and O radicals to act on the resist, thereby reducing the remaining dimension of the resist pattern (slimming). Occurs. In addition, since the reaction amount can be controlled by setting the irradiation amount, irradiation time, and water thickness to appropriate values, the slimming amount can be controlled. In addition, since the uniform oxidative decomposition reaction occurs slowly, the line edge roughness can be reduced. In this embodiment, water is used as the radical source, but the same effect can be obtained with hydrogen peroxide. When hydrogen peroxide water is used, light with a wavelength of 300 nm or less is preferably irradiated. It is also effective to use oxygen water or ozone water instead of water as these radical sources.
[0045]
In this embodiment, 172 nm light is used to make the resist pattern surface hydrophilic, but the present invention is not limited to this. Also, ozone (O _Three The same effect of hydrophilization can be obtained even if ozone water in which) is dissolved is supplied to the resist film surface. Since ozone water also has a function of removing particles after development, it may be hydrophilized in advance by using ozone water in the development rinsing step. Alternatively, the substrate to be processed may be placed in an atmosphere containing oxygen or ozone, and photo-excited to generate O radicals, and slimming treatment may be performed. FIG. 7 shows the wavelength dependence of the absorption coefficients of oxygen and ozone. In the case of ozone water, it is preferable to perform the slimming treatment by selecting a wavelength having a high absorption coefficient for both ozone and water from the characteristic diagrams shown in FIGS. In an atmosphere containing ozone or oxygen, a slimming process is performed by selecting a wavelength having a high absorption coefficient from the characteristic diagram shown in FIG.
[0046]
In this embodiment, an example of a resist pattern is shown as a pattern to be slimmed, but the application of this method is not limited to this.
[0047]
The pattern is not limited to this as long as the pattern size is reduced by water activated by light irradiation. It can also be used for slimming treatment of a resin-based insulating film. Further, it can be used for oxidation / modification treatment of the surface of a resin film such as an insulating film. Further, since the silicon nitride film pattern is also reduced in size, the pattern can be formed by this method. Of course, it can also be used when an oxide film is formed on the surface.
[0048]
It can also be used for resist film removal (regeneration) when a defect occurs in the resist pattern. In this case, the processing time is preferably set under the condition that the resist pattern disappears in the width direction. When a large pattern exists, the reaction product may be removed and the above process may be repeated.
[0049]
(Second Embodiment)
In the present embodiment, a slimming process is performed using a substrate processing apparatus different from that of the first embodiment. FIG. 8 is a diagram showing a schematic configuration of a substrate processing apparatus according to the second embodiment of the present invention. 8, parts that are the same as those shown in FIG. 3 are given the same reference numerals, and detailed descriptions thereof are omitted.
[0050]
As shown in FIG. 8, the wafer 100 is held on the lower surface of the substrate holding means 202, and the main surface of the wafer 100 (resist pattern forming surface) faces downward. The quartz glass 213 of the irradiation unit 210 is directed upward. The lamp 212 uses excimer lamp light that emits 222 nm light absorbed by water. In the bubbler 222, not pure water but hydrogen peroxide solution having a concentration of 5% is stored.
[0051]
The substrate processing of this embodiment will be described with reference to FIGS. FIG. 9 is a cross-sectional view showing a substrate processing method according to the second embodiment of the present invention.
[0052]
First, similarly to the first embodiment, the resist pattern 102 shown in FIG. 1A is formed (S101). Next, the substrate is transferred into the substrate processing apparatus shown in FIG. 8 (step S102). The main surface of the wafer 100 faces downward.
[0053]
Next, a mixed gas of hydrogen peroxide water vapor and nitrogen gas is supplied from the gas supply device 220 into the chamber 201. The humidity of the mixed gas is set to 80%. As shown in FIG. 9A, the hydrogen peroxide solution adsorption film 132 is formed on the surface of the resist pattern 102 by the hydrogen peroxide solution 131 (step S104).
[0054]
In this state, as shown in FIG. 10, the irradiation unit 210 is scanned on the main surface of the wafer 100 while irradiating the main surface of the wafer 100 with 222 nm light. The output of the lamp 212 is 50 mW / cm ² The scanning speed of the irradiation unit 210 was set to 2 mm / sec, and the distance between the quartz glass 213 and the wafer 100 was set to 1 mm. The scanning speed is 2 mm / sec, and the shape of the light irradiated from the irradiation unit 210 on the main surface of the wafer 100 is 40 mm in the scanning direction. Therefore, the time (slimming treatment time) during which the resist pattern is irradiated with light is 20 seconds. The temperature of the wafer 100 was adjusted to 100 ° C. by the substrate holding unit 202. FIG. 11 shows the wavelength dependence of the absorption coefficient of the hydrogen peroxide solution. As shown in FIG. 11, the absorption coefficient of hydrogen peroxide water has a large absorption coefficient with respect to a wavelength of 222 nm. Therefore, by irradiation with 222 nm light, OH radicals and O radicals are generated from the hydrogen peroxide solution by photoexcitation.
[0055]
As shown in FIG. 9B, irradiation with light 140 generates active radical molecules / atoms 113 from the vapor 131 and the adsorption film 132. The radical molecule / atom 113 and the resist pattern surface 102 react to reduce the width of the resist pattern 102. A reaction product 103 is formed by the reaction.
[0056]
The reaction product 103 causes a flow phenomenon because the temperature of the wafer 100 is set to 100 ° C. The reaction product 103 that has flowed moves to the tip of the pattern 102. The reaction product has a small surface tension and does not agglomerate even when it moves to the tip and becomes a wiggle. Since the tip of the resist pattern 102 is protected by the wiggly reaction product 103, etching in the thickness direction is suppressed.
[0057]
After the slimming, the surface of the resist pattern 102 is washed with water to dissolve the flaky reaction product, and a desired pattern can be obtained as shown in FIG.
[0058]
At this time, the slimming rate (speed at which the resist pattern narrows) was 3 nm / s, and the slimming amount was 60 nm. By these series of treatments, the resist pattern for gate processing which was 100 nm immediately after development can be thinned to 40 nm.
[0059]
Since the resist pattern obtained by the above-described method is anisotropically etched in the width direction during slimming, a film thickness that can sufficiently withstand the subsequent etching process can be ensured.
[0060]
The device using the gate created by processing the resist pattern created in this way as a mask could be processed to be much finer than the gate dimensions used without performing this treatment, so it was possible to obtain excellent responsiveness. .
[0061]
According to the present embodiment, the resist pattern can be efficiently narrowed, and a device created using this technique can obtain superior responsiveness as compared with that produced by the conventional technique.
[0062]
Although a chemically amplified resist having reactivity with ArF is used as the resist used in this embodiment, the present invention is not limited to this, and other resists such as alicyclic resins (acrylic, coma, and hybrid resins) are used. The same effect was obtained. In addition, any alcoholic OH group can be applied as long as an alcoholic OH group is generated by addition reaction of OH radicals generated by ultraviolet light irradiation. Also effective for resins with aromatic compounds, I-line with novolac resin, G-ray resist, KrF resist composed of resin with polyvinylphenol skeleton, electron beam exposure resist, soft X-ray (EVU) The effect was also confirmed for the resist for exposure. When a resin having an aromatic compound is used, a higher slimming rate can be obtained by using alkaline water such as a TMAH (tetramethylammonium oxide) solution or a KOH solution.
[0063]
In this embodiment, hydrogen peroxide water is used as a substance that generates OH radicals, but the present invention is not limited to this, and the same effect can be obtained even when pure water is used and irradiated with light of 200 nm or less. Further, the concentration is not limited to this, and a slimming effect was confirmed in a concentration range from 1 ppm to 30%. The substrate temperature is preferably adjusted in the range of 30 to 50 ° C. when hydrogen peroxide is used, and in the range of 30 to 90 ° C. when pure water is used.
[0064]
In the case of this embodiment, the substrate to be processed can be heated to a state where the resist pattern does not flow after slimming to vaporize and remove the reaction product. Further, even during the slimming treatment, the introduced gas may be heated to raise the temperature of the resist surface to vaporize a part of the resist while forming a tsura.
[0065]
Of course, removal by washing with water is also possible. For drying when washing with water, if supercritical carbonated water is used, good processing without pattern collapse is possible. The substrate to be processed is transferred to the high-pressure chamber, and the pure water on the main surface of the substrate to be processed after the slimming process is first replaced with alcohol in which carbonic acid is soluble. Furthermore, this alcohol is converted into liquid CO ₂ Replace with. Liquid CO ₂ The drying from the state is 35 ° C., 10 Mpa, and CO in the supercritical state ₂ After changing the state, gradually reduce the chamber pressure to reduce the CO ₂ Vaporize and remove.
[0066]
In this embodiment, when cleaning with pure water, hydrogen peroxide solution or alcohol is performed after slimming, unevenness caused by condensation of the swelling layer generated during the wet treatment may be noticeable on the resist pattern surface. . In such a case, the resist pattern surface may be finally irradiated with light of 172 nm in an oxygen or ozone atmosphere. The swelling layer is a so-called reaction intermediate product, and can be selectively peeled off by performing the above-described treatment. As a result, a pattern surface with less unevenness can be formed, and the reliability of the device can be further enhanced.
[0067]
The pattern is not limited to this as long as the pattern size is reduced by water activated by light irradiation. It can also be used for slimming treatment of a resin-based insulating film. Further, since the silicon nitride film pattern is also reduced in size, the pattern can be formed by this method.
[0068]
In this embodiment, an example of a resist pattern is shown as a pattern to be slimmed, but the application of the present invention is not limited to this. It can also be used for resist film removal (regeneration) when a defect occurs in the resist pattern. In this case, the processing time is preferably set under the condition that the resist pattern disappears in the width direction. When a large pattern exists, the reaction product may be removed and the above process may be repeated.
[0069]
(Third embodiment)
First, the structure of the substrate processing apparatus used for the slimming process of this embodiment is demonstrated with reference to FIG. In addition, the same code | symbol is attached | subjected to the site | part same as FIG. 3, and detailed description is abbreviate | omitted. The configuration of the gas supply unit 220 is the same as the gas introduction unit of the apparatus shown in FIG.
[0070]
A holder 242 for holding the wafer 100 with its main surface facing downward is provided in the chamber 201. The holder 242 holds the wafer 100 by, for example, a vacuum chuck. The holder 242 has a temperature adjustment function for adjusting the temperature of the wafer 100. An irradiation unit 250 is provided to face the main surface of the wafer 100. The irradiation unit 250 emits light of 251 nm and 172 nm in the lamp house. ₂ An excimer lamp 252, a quartz glass 253, a reflector 256, and a diffusion plate 257 are provided.
[0071]
Next, a slimming process using the apparatus shown in FIG. 12 will be described.
First, similarly to the first embodiment, the resist pattern 102 shown in FIG. 1A is formed (S101).
[0072]
The antireflection film is formed by a spin coating method. Heating is performed at 300 ° C. for 120 seconds to volatilize the solvent, and an antireflection film having a thickness of 100 nm is formed. Here, an organic material is used as the antireflection film. A resist film is formed by a spin coating method. Heating is performed at 130 ° C. for 60 seconds to volatilize the solvent, thereby forming a resist film having a thickness of 200 nm. The resist film is a chemically amplified positive resist for ArF light (wavelength 193 nm). Next, an ArF excimer laser is used to perform reduction projection exposure of the gate processing pattern via the exposure reticle. The substrate is heat treated and conveyed to a developing device. In the developing device, a developing solution is supplied onto the substrate to be processed, and after developing for 30 seconds, pure water is supplied while rotating the substrate to be processed, the reaction is stopped and washed, and the substrate to be processed is dried by spin drying. . By performing these processes, an isolated remaining pattern of 100 nm is formed on the substrate to be processed.
[0073]
Next, the wafer is transferred into the substrate processing apparatus shown in FIG. The main surface of the wafer 100 faces downward.
Next, the substrate to be processed that has been developed is transferred into the chamber by a transfer robot, and a resist pattern for gate is slimmed by light irradiation.
[0074]
Nitrogen gas containing pure water having a temperature of 23 ° C. and a humidity of 70% is supplied from the gas supplier 220. To adjust the humidity of nitrogen gas, a portion of the nitrogen gas is passed through a bubbler in which pure water heated to a temperature higher than that of the nitrogen gas to be introduced is passed, and moisture is mixed with pure nitrogen and the bubbler. This was done by adjusting the temperature to 23 ° C.
[0075]
Next, the wafer 100 that is irradiated with light from the irradiation unit 250 is irradiated with light to perform a slimming process. The output of the lamp 252 is 50 mW / cm ² The irradiation time was 30 seconds and the distance between the quartz glass 253 and the wafer 100 was 5 mm. At this time, the vacuum pump was controlled by a valve so that the pressure in the chamber was 19998.3 Pa (150 mmHg).
[0076]
The slimming process of this embodiment will be described with reference to FIG. FIG. 13 is a cross-sectional view showing a method of manufacturing a semiconductor device according to the third embodiment of the present invention.
First, as shown in FIG. 13A, the vapor in the chamber 201 is irradiated with light to generate radical molecules / atoms 113 such as OH radicals and O radicals. The radical molecules / atoms 113 and the resist pattern 102 react to form a reaction product 103 on the resist pattern surface, and the line width of the resist pattern 102 is reduced. The reaction product 103 is warmed by the radiant heat of the light 140, and a flow phenomenon occurs. As shown in FIG. 13B, the reaction product 103 near the tip of the resist pattern 102 moves to the tip of the resist pattern 102 due to fluidization, and the reaction at the tip of the resist pattern 102 is suppressed. Further, the fluidized reaction product 103 evaporates, and the resist pattern surface is exposed on the side surface of the resist pattern 102.
[0077]
Lamp irradiation, irradiation time, irradiation conditions such as the distance between the quartz glass and the substrate to be processed, and temperature control of the holder so that the surface temperature of the resist and the antireflection film is less than the thermal decomposition temperature during UV irradiation. Control the function.
[0078]
Irradiation with an excimer lamp while removing reaction products promotes the reaction between the unreacted resist surface and OH radicals or O radicals.
[0079]
Next, the substrate is transported to a cleaning unit by a transport robot, rinse liquid (for example, pure water) is supplied from a rinse nozzle disposed above the substrate to be processed, and the substrate is cleaned for 30 seconds while rotating, so that the pattern surface layer is slightly The remaining reaction product was dissolved, and a desired pattern could be obtained. Through these series of treatments, a 100 nm gate processing resist pattern could be thinned to 60.5 nm (FIG. 13C). At this time, the film thickness of the resist is almost 197 nm, and the film thickness is hardly changed and is anisotropically etched in the width direction at the time of slimming, so that a film thickness that can sufficiently withstand the subsequent etching process can be secured. .
[0080]
The device using the gate created by processing the resist pattern created as described above as a mask could be processed much finer than the gate dimensions used without performing this process, so it was possible to obtain excellent responsiveness. It was.
[0081]
It is also effective for slimming to perform a series of these processes from the excimer lamp irradiation process to the cleaning process under reduced pressure. In addition, when performing a plurality of times, it is effective to measure the dimension of the resist pattern after each series of processes. By measuring the resist pattern dimensions, the reaction amount can be known. Depending on the reaction amount, the irradiation amount of the light irradiation unit, the irradiation time, the distance between the quartz glass and the substrate to be processed, and the irradiation conditions such as the humidity and oxygen concentration in the chamber are controlled to achieve the desired reaction amount. do it.
[0082]
In this embodiment, the pressure in the chamber was set at 19998.3 Pa (150 mmHg). However, the pressure is not limited to this, and the humidity and oxygen concentration are sufficient to generate OH radicals and O radicals sufficient to narrow the resist pattern. Just do it.
[0083]
In this embodiment, in this embodiment, a part of nitrogen gas is passed through a bubbler, and moisture is mixed with pure nitrogen and the bubbler and then introduced into the chamber. However, the atmosphere in the chamber is not limited to this. A gas obtained by mixing ozone gas or hydrogen peroxide gas into the atmosphere may be introduced into the chamber.
[0084]
Hydrogen peroxide gas can generate OH radicals and O radicals. In particular, hydrogen peroxide gas can generate bimolecular OH radicals from one molecule. On the other hand, ozone also generates O radicals, so that a slimming reaction is possible.
[0085]
The wavelength of the excimer lamp may be any wavelength as long as OH radicals and / or O radicals are generated. Further, the lamp output, the irradiation time, and the distance from the window material to the sample are only described here, and may be set to any values as long as it can be confirmed that a reaction occurs. The window material is CaF ₂ But it ’s okay.
[0086]
In this embodiment, the slimming process is performed with the resist pattern forming surface facing downward. However, the resist pattern forming surface may be directed upward. The pattern is not limited to this as long as the pattern size is reduced by water activated by light irradiation. It can also be used for slimming treatment of a resin-based insulating film. Further, since the silicon nitride film pattern is also reduced in size, the pattern can be formed by this method.
[0087]
(Fourth embodiment)
In the present embodiment, as in the first to third embodiments, an example in which a resist pattern is slimmed by irradiating an excimer lamp after the resist pattern is formed will be described.
[0088]
A resist pattern is formed under the same conditions as in the third embodiment.
[0089]
Next, the substrate to be processed is transferred into the chamber 201 of the substrate processing apparatus shown in FIG. 12 by the transfer robot. The wafer 100 is held with the main surface (resist pattern forming surface) facing down.
[0090]
The following procedure will be described with reference to FIG. FIG. 14 is a cross-sectional view showing a manufacturing process of a semiconductor device according to the fourth embodiment of the present invention.
[0091]
Next, nitrogen gas containing pure water having a temperature of 23 ° C. and a humidity of 70% is supplied from the gas supply means. Humidity adjustment with nitrogen gas was performed by passing a part of the nitrogen gas through a bubbler in which pure water heated to a temperature higher than the temperature of the nitrogen gas to be introduced was stored, and mixing the vapor into the pure nitrogen gas with the bubbler. . Note that the pressure of the chamber 201 is set to atmospheric pressure. The temperature of the substrate to be processed is adjusted to 0 ° C. As shown in FIG. 14A, the introduced moisture is condensed on the surface of the resist pattern 102 due to the temperature difference, and a water adsorption film 132 is formed on the surface of the resist pattern.
[0092]
Light 140 is irradiated from the irradiation unit 250 to generate active OH radicals and O radicals, and a resist pattern is slimmed by the generated radicals. In this embodiment, Xe with a wavelength of 172 nm ₂ Excimer lamp light was irradiated. Lamp output 50mW / cm ² The irradiation time was 20 seconds and the distance between the quartz glass and the substrate to be processed was 5 mm.
[0093]
At the time of excimer lamp irradiation, OH radicals or O radicals are generated from the water adsorption film 132, and the reaction between the resist pattern and the radicals proceeds. On the other hand, since the temperature of the pattern surface rises due to the reaction heat due to light irradiation, the fluidity of the reaction product 103 increases and becomes a wiggle (FIG. 14B). Since the tip of the resist pattern 102 is protected by the wiggly reaction product 103, etching in the thickness direction is suppressed.
[0094]
Next, light irradiation is temporarily stopped, and the pressure in the chamber is reduced to 19998.3 Pa (150 mmHg) while the wafer 100 is heated to 50 ° C. As shown in FIG. 14C, by heating the substrate to be processed 101 under a reduced pressure, the icicle-like reaction product 103 is evaporated and an unreacted resist appears on the surface of the resist pattern 102. At this time, the processing time is adjusted so that the reaction product 103 at the tip of the resist pattern 102 is not removed.
[0095]
The reaction product 103 is removed by repeating a series of processes of the cooling process of the substrate 101 to be processed → the irradiation process of the excimer lamp → the process of heating the substrate to be processed under reduced pressure, and the unreacted resist surface and OH radicals or Reaction with O radicals can be promoted. The surface temperature of the resist rises due to the radiation of the excimer lamp. The lamp output, the irradiation time, the distance between the quartz glass and the substrate to be processed, etc. so that the surface temperature is lower than the thermal decomposition temperature of the resist and the antireflection film. Control the irradiation conditions.
[0096]
Next, the substrate is transported to a cleaning unit by a transport robot, rinse liquid (for example, pure water) is supplied from a rinse nozzle disposed above the substrate to be processed, and the substrate is cleaned for 30 seconds while rotating, so that the pattern surface layer is slightly The remaining reaction product 103 was dissolved and a desired pattern was obtained (FIG. 14 (d)). Through this series of treatments, the size of the 100 nm gate processing resist pattern could be reduced to 50 nm. At this time, the film thickness of the resist is 197.5 nm and there is almost no variation of the film thickness, and since the anisotropic etching is performed in the width direction during slimming, the film thickness that can sufficiently withstand the subsequent etching process is obtained. It can be secured.
[0097]
The device using the gate created by processing the resist pattern created as described above as a mask could be processed much finer than the gate dimensions used without performing this process, so it was possible to obtain excellent responsiveness. It was.
[0098]
In this embodiment, water molecules are adsorbed on the resist surface by cooling the substrate to be processed, and reaction products are removed from the resist pattern surface by heating the substrate to be processed under reduced pressure. The method for promoting the reaction between the radical and the resist pattern surface layer is not limited to this. With the temperature of the substrate to be processed kept constant, the pressure in the chamber is increased to adsorb water molecules on the resist pattern surface, and after irradiation with an excimer lamp, this time the chamber is decompressed to reduce OH radicals or The reaction product generated by the O radical can be vaporized, and the resist pattern can be processed finely by controlling the pressure in the chamber before and after the irradiation with the excimer lamp.
[0099]
The wavelength of the excimer lamp may be any wavelength as long as OH radicals and / or O radicals are generated. Further, the lamp output, the irradiation time, and the distance from the window material to the sample are only described here, and may be set to any values as long as it can be confirmed that a reaction occurs. The window material is CaF ₂ But it ’s okay.
[0100]
It is also effective for slimming to perform a series of processes from the cooling process to the cleaning process of the substrate to be processed a plurality of times. In addition, when it is performed a plurality of times, it is effective to measure the dimension of the resist pattern after each series of processing as in the first embodiment.
[0101]
Further, in this embodiment, a part of nitrogen gas is passed through a bubbler and water vapor is mixed with pure nitrogen and the bubbler and then introduced into the chamber. However, the atmosphere in the chamber is not limited to this, as in the first embodiment. Alternatively, a gas obtained by mixing ozone gas or hydrogen peroxide gas into the atmosphere may be introduced into the chamber.
[0102]
The present invention is not limited to the above-described embodiments, and various modifications can be made without departing from the scope of the invention at the stage of implementation. Further, the above embodiments include inventions at various stages, and various inventions can be extracted by appropriately combining a plurality of disclosed constituent elements. For example, even if some constituent requirements are deleted from all the constituent requirements shown in the embodiment, the problem described in the column of the problem to be solved by the invention can be solved, and the effect described in the column of the effect of the invention Can be obtained as an invention.
[0103]
【The invention's effect】
As described above, according to the present invention, the pattern of the resin film can be thinned by cooling the substrate to be processed to a temperature at which the generated reaction product does not flow. Further, by reacting OH radicals and / or O radicals with the resin film with the surface on which the resin film is formed facing down, the resin film pattern can be reduced, and the resin film thickness can be reduced. Can be suppressed. In addition, when the ultraviolet light is irradiated, the reaction product evaporates in the environment around the substrate to be processed, and the resin film pattern is thinned by setting the temperature of the resin film below the decomposition temperature. be able to.
[Brief description of the drawings]
FIG. 1 is a flowchart showing a processing procedure of a pattern forming method according to a first embodiment.
FIG. 2 is a cross-sectional view showing the method for manufacturing the semiconductor device according to the first embodiment.
FIG. 3 is a diagram showing a configuration of a substrate processing apparatus according to the first embodiment.
4 is a diagram showing a configuration of an irradiation unit of the substrate processing apparatus shown in FIG. 3;
FIG. 5 is a characteristic diagram showing the wavelength dependence of the absorption coefficient of water.
FIG. 6 is a diagram showing a movement state of an irradiation unit of a substrate processing apparatus during a slimming process.
FIG. 7 is a characteristic diagram showing the wavelength dependence of oxygen and ozone.
FIG. 8 is a diagram showing a schematic configuration of a substrate processing apparatus according to a second embodiment.
FIG. 9 is a cross-sectional view showing a method for manufacturing a semiconductor device according to a second embodiment.
FIG. 10 is a diagram illustrating a moving state of an irradiation unit of the substrate processing apparatus during a slimming process.
FIG. 11 is a characteristic diagram showing the wavelength dependence of the absorption coefficient of hydrogen peroxide water.
FIG. 12 is a diagram showing a configuration of a substrate processing apparatus according to a third embodiment.
FIG. 13 is a cross-sectional view showing a method for manufacturing a semiconductor device according to a third embodiment.
FIG. 14 is a cross-sectional view showing a method for manufacturing a semiconductor device according to a fourth embodiment.
FIG. 15 is a diagram used for explaining the problems of slimming treatment using radical molecules and atoms generated by photoexcitation.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 100 ... Wafer, 101 ... Substrate to be processed, 102 ... Resist pattern, 103 ... Reaction product, 111 ... Water vapor, 112 ... Adsorption film, 113 ... OH radical, 113 ... Radical molecule, 120 ... Light, 131 ... Steam, 132 ... Adsorption film

Claims (10)

Forming a resin film pattern on the main surface of the substrate to be processed;
Making the main surface of the substrate to be processed face downward;
Contacting the main surface of the substrate to be treated with an atmosphere containing molecules that are irradiated with ultraviolet light to generate OH radicals and / or O radicals;
Irradiating the ultraviolet light to the main surface of the substrate to be processed;
Generating OH radicals and / or O radicals from the molecules by the ultraviolet light;
Reacting the generated OH radical and / or O radical with the resin film to generate a reaction product, thereby reducing the pattern dimension of the resin film ;
Heating the substrate to be processed so that the reaction product evaporates at a temperature lower than the decomposition temperature of the resin film upon irradiation with the ultraviolet light;
After irradiation of the ultraviolet light, a method of manufacturing a semiconductor device which comprises a step of removing the reaction product. Wherein during the heating of the substrate, a manufacturing method of a semiconductor device according to claim 1, wherein the target substrate is characterized in that it is placed under a pressure less than atmospheric pressure. Method for producing a molecule, oxygen and a semiconductor device according to claim 1, wherein the the one of ozone which has been selected more than one. After removal of the reaction products, the manufacturing method of a semiconductor device according to claim 1, wherein the etching the substrate to be processed the resin film as a mask. 2. The method of manufacturing a semiconductor device according to claim 1 , wherein after the reaction product is removed, the main surface of the substrate to be processed is irradiated with ultraviolet light or an electron beam. The removal of the reaction product includes a step of supplying a solution that dissolves the reaction product to the main surface of the substrate to be processed, and a step of removing the solution from the main surface of the substrate to be processed. A method for manufacturing a semiconductor device according to claim 1 . The method of manufacturing a semiconductor device according to claim 6 , wherein the solution is water or hydrogen peroxide water. The method for manufacturing a semiconductor device according to claim 6 , further comprising a step of drying the main surface of the substrate to be processed after the removal of the solution. The removal of reaction products, the manufacturing method of a semiconductor device according to claim 1, wherein said reaction product is characterized in that carried out by heating the target substrate to a temperature to vaporize. The method for manufacturing a semiconductor device according to claim 9 , wherein a heating temperature of the substrate to be processed is lower than a thermal decomposition temperature of the resin film.

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