JP3907504B2 - Semiconductor device manufacturing method and semiconductor device manufacturing mold - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a method of manufacturing a semiconductor device and a mold for manufacturing a semiconductor device, and more particularly to a nanoimprint lithography technique for forming a resist pattern by pressing a patterned mold against a resist applied on a substrate. It is.
[0002]
[Prior art]
The basic principle of nanoimprint lithography technology is described, for example, in Document 1 below.
[0003]
Reference 1: SY Chou et al., “Nanoimprint lithography”, J. Vac. Sci. Technol. B 14 (6), Nov / Dec 1996, pp.4129-4133
FIG. 4 is a diagram showing the basic principle of the nanoimprint lithography technique disclosed in Document 1. Referring to FIG. 4A, first, a photoresist 102 is applied on the surface of the substrate 103. The substrate 103 is heated above the glass transition point temperature of the photoresist 102, and the mold 101 is pressed against the softened photoresist 102. A pattern made of unevenness is formed on the surface of the mold 101.
[0004]
With reference to FIG. 4B, the temperature of the substrate 103 is lowered below the glass transition temperature of the photoresist 102 while the mold 101 is pressed against the photoresist 102. Thereafter, the mold 101 is separated from the photoresist 102.
[0005]
At this time, the residue 102a of the photoresist 102 remains in the region compressed by the convex portion of the pattern of the mold 101. Therefore, the residue 102a is removed by, for example, ECR (Electron Cyclotron Resonance) etching.
[0006]
Referring to FIG. 4C, a desired resist pattern 102 can be obtained by the etching described above.
[0007]
In the nanoimprint lithography technique, a method different from the above is described in Document 2 below.
[0008]
Reference 2: T. Bailey et al., “Step and flash imprint lithography: Template surface treatment and defect analysis”, J. Vac. Sci. Technol. B 18 (6), Nov / Dec 2000, pp.3572-3577
FIG. 5 is a diagram showing a scheme of the nanoimprint lithography technique disclosed in the above-mentioned document 2. With reference to FIG. 5A, in this method, first, a liquid photocurable resin 204 is placed on an etching target layer 202 on a semiconductor substrate 203 and pressed by a quartz mold 201.
[0009]
Referring to FIG. 5B, UV (ultraviolet) light 205 is irradiated in a state where the photocurable resin 204 is pressed by the quartz mold 201. Since the quartz mold 201 is transparent to the UV light, the UV light 205 is irradiated to the photocurable resin 204 through the quartz mold 201. Thereby, the photocurable resin 204 is cured.
[0010]
Referring to FIG. 5C, thereafter, the mold 201 is pulled away from the photocurable resin 204, and a pattern is formed on the photocurable resin 204. The residue 204a remaining at the bottom of the pattern of the photocurable resin 204 and the etching target layer 202 are etched by plasma etching.
[0011]
With reference to FIG. 5D, a desired pattern is formed on the etching target layer 202 by the etching described above.
[0012]
In the method shown in FIG. 5, since it is not necessary to raise the substrate temperature to a high temperature by using the UV curable resin 204, there is an effect of suppressing the positional deviation of the pattern.
[0013]
[Problems to be solved by the invention]
Since the conventional nanoimprint lithography shown in FIG. 4 is a mechanical processing method for the photoresist 102, a residue 102a of the photoresist 102 is always generated in a region pressed by the mold 101. The residue 102a needs to be removed by a technique such as dry etching. However, this etching has a problem that the shape of the resist pattern 102 is deteriorated and the dimension controllability is deteriorated.
[0014]
Further, in the nanoimprint at room temperature by the combination of the transparent mold 201 and the photocurable resin 204 shown in FIG. 5, the pattern formed on the photocurable resin 204 contracts and becomes smaller than the pattern size on the mold 201. Dimensional controllability deteriorates. Further, as the pattern size becomes finer, it becomes difficult for light to enter between the patterns formed on the mold 201. This makes it difficult for the resin 204 to sufficiently absorb light energy, and there is a problem that a fine pattern cannot be formed.
[0015]
The present invention has been made to solve the above-described problems, and eliminates the etching process by eliminating the residue of the pattern obtained by pressing the mold. It is intended to make it possible to form.
[0016]
[Means for Solving the Problems]
The method for manufacturing a semiconductor device of the present invention includes the following steps. First, the pattern-formed mold is pressed against the photoresist. With the mold pressed against the photoresist, irradiation light is selectively irradiated to the photoresist through the mold. By developing the photoresist, the region not irradiated with the irradiation light of the photoresist is removed, and the photoresist is patterned. The mold includes a substrate having a pattern made of unevenness on the surface pressed against the photoresist, and a light-shielding film that blocks transmission of irradiation light on the front end surface of the unevenness.
[0017]
According to the method for manufacturing a semiconductor device of the present invention, a residue is not generated between patterns by developing after irradiating irradiation light with a photoresist pressed by a mold. For this reason, the etching for removing the residue is unnecessary, and it is possible to prevent the pattern shape deterioration and the dimensional controllability deterioration due to the etching.
[0018]
In addition, since a photoresist is used, pattern shrinkage does not occur as in the case of using a photocurable resin, and the dimensional controllability is good also in this respect.
[0020]
The mold also has a substrate having a pattern made of unevenness on the surface pressed against the photoresist, and a light-shielding film that blocks transmission of irradiation light on the front end surface of the unevenness. As a result, the negative photoresist portion compressed on the base convex portion is not irradiated with light, and therefore can be removed by development, and the generation of residues can be prevented.
[0021]
In the above method for manufacturing a semiconductor device, the substrate is transparent to the irradiation light.
As a result, it is possible to irradiate the photoresist with irradiation light in a state where the mold is pressed against the photoresist.
[0022]
In the above method for manufacturing a semiconductor device, the refractive indexes of the base and the photoresist with respect to the irradiation light are preferably equal.
[0023]
This eliminates the optical interface at the interface between the mold and the photoresist, so that the pattern can be easily formed even when the pattern size is equal to or smaller than the wavelength of the irradiation light. Therefore, formation of a fine pattern becomes easy.
[0024]
In the method for manufacturing a semiconductor device described above, preferably, the photoresist is pressed by the mold until the thickness of the photoresist compressed by the convex portion of the substrate becomes ¼ or less of the wavelength of the irradiation light.
[0025]
Thereby, the photoresist can absorb the energy of irradiation light to the interface with the substrate.
[0026]
In the semiconductor device manufacturing method, the irradiation light is preferably either UV light or excimer light.
[0027]
In this way, it is possible to easily form a fine pattern using UV light and excimer light.
[0028]
Preferably, in the above method for manufacturing a semiconductor device, the mold has a base having a laminated structure of a substrate and a pattern portion, both the substrate and the pattern portion are transparent to irradiation light, and the pattern The refractive index for the irradiated light of the part and the photoresist is equal.
[0029]
As described above, even in the laminated structure of the substrate and the pattern portion, the same effect as that of the single mold base can be obtained.
[0030]
In the method for manufacturing a semiconductor device described above, the step of pressing the mold against the photoresist is performed in a state where the solvent in the photoresist is released by pre-baking the photoresist and the photoresist is heated to the softening point.
[0031]
Thereby, a photoresist can be easily processed with a mold.
[0032]
The mold for manufacturing a semiconductor device of the present invention is a mold for manufacturing a semiconductor device that is pressed against a photoresist in order to form a pattern on the photoresist, and has a substrate having a pattern made of unevenness on the surface pressed against the photoresist, and the unevenness thereof. And a light-shielding film that blocks transmission of irradiation light.
[0033]
According to the mold for manufacturing a semiconductor device of the present invention, no residue is generated between patterns by developing after irradiating irradiation light with a photoresist pressed by a mold. For this reason, the etching for removing the residue is unnecessary, and it is possible to prevent the pattern shape deterioration and the dimensional controllability deterioration due to the etching.
[0034]
In addition, by using this mold for manufacturing a semiconductor device, a photoresist can be used in place of the photocurable resin, so that pattern shrinkage does not occur as in the case of using the photocurable resin.
[0035]
In the above mold for manufacturing a semiconductor device, the substrate is transparent to the irradiation light applied to the photoresist.
[0036]
As a result, it is possible to irradiate the photoresist with irradiation light in a state where the mold is pressed against the photoresist.
[0037]
In the above-mentioned mold for manufacturing a semiconductor device, the refractive index with respect to the irradiation light of the substrate is preferably equal to the refractive index with respect to the irradiation light of the photoresist.
[0038]
This eliminates the optical interface at the boundary surface between the mold and the photoresist, so that the pattern can be easily shaped even if the pattern size is equal to or smaller than the wavelength of the irradiation light. Therefore, formation of a fine pattern becomes easy.
[0039]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described with reference to the drawings.
[0040]
(Embodiment 1)
FIG. 1 is a flowchart showing a method of manufacturing a semiconductor device according to the first embodiment of the present invention in the order of steps. Referring to FIG. 1A, first, a mold 1 having a base 1a and a light shielding film 1b is prepared. The base 1a of the mold 1 has a fine pattern made of unevenness on the surface, and a light-shielding film 1b is formed on the entire front surface of the protrusion of the unevenness. The substrate 1a is made of a material transparent to the irradiation light 7, and is made of, for example, quartz. The light shielding film 1b is made of a material that blocks the transmission of the irradiation light 7, and is made of, for example, a chromium (Cr) thin film.
[0041]
Next, for example, a negative photoresist 2 is applied on the surface of the semiconductor substrate 3. The photoresist 2 is heated to the softening point of the photoresist 2 by releasing the solvent in the photoresist 2 by pre-baking.
[0042]
Referring to FIG. 1B, the mold 1 is pressed against the photoresist 2 in a state where the photoresist 2 is heated to the softening point. As a result, the photoresist 2 is deformed, and a pattern portion (convex portion) 2 b and a residue portion (concave portion) 2 c are formed in the photoresist 2. In a state where the mold 1 is pressed against the photoresist 2, the irradiation light 7 is irradiated onto the photoresist 2 from the mold 1 side. Since the mold 1 is made of a material transparent to the irradiation light 7, the irradiation light 7 is irradiated to the photoresist 2 through the mold 1. However, since the light shielding film 1 b is made of a material that does not transmit the irradiation light 7, the irradiation light 7 is not irradiated to the residue 2 c of the photoresist 2.
[0043]
Since the photoresist 2 is of a negative type, the photoresist 2 absorbs the energy of the irradiation light 7 in the pattern portion 2b irradiated with the irradiation light 7 to cause a crosslinking reaction and is insoluble in the resist developer. Become. On the other hand, since the irradiated light 7 is not irradiated on the residue portion 2c, the photoresist 2 does not absorb the energy of the irradiated light 7 and does not cause a crosslinking reaction, and therefore remains soluble in the resist developer. From this state, the mold 1 is separated from the photoresist 2.
[0044]
Referring to FIG. 1C, after the mold is separated, the photoresist 2 is developed with a resist developer. At this time, the pattern portion 2b of the photoresist 2 is insoluble in the resist developer, but the residue portion 2c is soluble, so that only the photoresist 2 in the residue portion 2c portion is removed by development. .
[0045]
Referring to FIG. 1D, the residue of the photoresist 2 located between the pattern portions 2b can be removed by the above development.
[0046]
In the present embodiment, the residue between the pattern portions 2 b of the photoresist 2 can be removed by developing after irradiating the irradiation light 7 while the photoresist 2 is pressed by the mold 1. For this reason, the etching for removing the residue is unnecessary, and it is possible to prevent the pattern shape deterioration and the dimensional controllability deterioration due to the etching.
[0047]
Further, since the photoresist 2 is used, the pattern shrinkage does not occur as in the case of using the photo-curing resin, and the dimension controllability is good also in this respect.
[0048]
(Embodiment 2)
FIG. 2 is a schematic cross-sectional view for illustrating the method for manufacturing the semiconductor device in the second embodiment of the present invention. Referring to FIG. 2, the present embodiment is different from the first embodiment in the material of base 1a of mold 1, the size of pattern of mold 1, and the degree of pressing of photoresist 2 by mold 1.
[0049]
The base body 1a is made of a material whose refractive index with respect to the irradiation light 7 of the base body 1a is the same as the refractive index with respect to the irradiation light 7 of the photoresist 2. The pattern of the mold 1 has a pattern size smaller than the wavelength of the irradiation light 7, for example, the same size as the thickness T of the resist residue portion (concave portion) 2 c in the region pressed by the mold 1. Further, the mold 1 presses the photoresist 2 until the thickness T of the resist residue portion 2c in the region pressed by the mold 1 becomes 1/4 or less of the wavelength of the irradiation light 7.
[0050]
Since the apparatus configuration and manufacturing process other than the above are substantially the same as those in the first embodiment, the same members are denoted by the same reference numerals, and the description thereof is omitted.
[0051]
In FIG. 2, a region 8 indicated by a one-dot chain line indicates a region where the irradiation light 7 can enter. Since the refractive index with respect to the irradiation light 7 of the substrate 1a of the mold 1 is equal to the refractive index with respect to the irradiation light 7 of the photoresist 2, the optical interface between the substrate 1a of the mold 1 and the photoresist 2 is eliminated. Thereby, the irradiation light 7 irradiates the whole area 8. As a result, since the negative photoresist 2 absorbs the energy of the irradiation light 7 only by the pattern portion 2b, it is possible to form a pattern without a residue by performing the development process.
[0052]
Also, this method is effective even when the pattern size to be formed is equal to or less than the wavelength of the irradiation light 7 because the optical interface is eliminated between the base 1a of the mold 1 and the photoresist 2.
[0053]
Further, by applying pressure until the thickness T of the resist residue portion 2c in the region pressed by the mold 1 is ¼ or less of the wavelength of the irradiation light 7, the pattern portion 2b of the photoresist 2 becomes the substrate 3 and the photoresist 2 The energy of the irradiation light 7 can be absorbed up to the interface.
[0054]
(Embodiment 3)
FIG. 3 is a schematic cross sectional view for illustrating the method for manufacturing the semiconductor device in the third embodiment of the present invention. Referring to FIG. 3, the present embodiment is different from the first embodiment in that the substrate constituting mold 1 has a laminated structure of substrate 1a ₁ and pattern portion 1a ₂ .
[0055]
By forming the pattern portion 1a _{2 on} the surface of the substrate 1a _1, a pattern made of unevenness is formed on the surface of the mold 1. The light shielding film 1b is formed on the tip the entire surface of the pattern portion 1a ₂ to block the transmission of irradiated light 7.
[0056]
Both the substrate 1 a ₁ and the pattern portion 1 a ₂ are made of a material that is transparent to the irradiation light 7. In particular, the pattern portion 1 a ₂ is made of a material whose refractive index with respect to the irradiation light 7 is substantially equal to the refractive index of the photoresist 2.
[0057]
In addition, since apparatus configurations and manufacturing methods other than this are almost the same as those of the first embodiment described above, the same members are denoted by the same reference numerals, and description thereof is omitted.
[0058]
In the present embodiment as well, as in the second embodiment described above, pressurization is performed until the thickness T of the residue portion 2c in the region pressed by the mold 1 is ¼ or less of the wavelength of the irradiation light 7. The pattern region portion (convex portion) 2 b can absorb the energy of the irradiation light 7 up to the interface between the substrate 3 and the photoresist 2.
[0059]
According to the present embodiment, the same effects as those of the first embodiment can be obtained, and it is not necessary to prepare the base body of the mold 1 integrally, so that the degree of freedom in design is increased.
[0060]
The embodiment disclosed this time should be considered as illustrative in all points and not restrictive. The scope of the present invention is defined by the terms of the claims, rather than the description above, and is intended to include any modifications within the scope and meaning equivalent to the terms of the claims.
[0061]
【The invention's effect】
As described above, according to the method for manufacturing a semiconductor device of the present invention, a residue is not generated between patterns by developing after irradiating irradiation light with a photoresist pressed by a mold. For this reason, the etching for removing the residue is unnecessary, and it is possible to prevent the pattern shape deterioration and the dimensional controllability deterioration due to the etching.
[0062]
In addition, since a photoresist is used, pattern shrinkage does not occur as in the case of using a photocurable resin, and the dimensional controllability is good also in this respect.
[0063]
In the semiconductor device manufacturing method described above, the mold has a base having a pattern made of unevenness on the surface pressed against the photoresist, and a light-shielding film that blocks transmission of irradiation light on the surface of the protrusion of the unevenness. . As a result, the negative photoresist portion compressed on the base convex portion is not irradiated with light, and therefore can be removed by development, and the generation of residues can be prevented.
[0064]
In the above method for manufacturing a semiconductor device, the substrate is transparent to the irradiation light. As a result, it is possible to irradiate the photoresist with irradiation light in a state where the mold is pressed against the photoresist.
[0065]
In the above method for manufacturing a semiconductor device, the refractive indexes of the base and the photoresist with respect to the irradiation light are preferably equal. This eliminates the optical interface at the interface between the mold and the photoresist, so that the pattern can be easily formed even when the pattern size is equal to or smaller than the wavelength of the irradiation light. Therefore, formation of a fine pattern becomes easy.
[0066]
In the method for manufacturing a semiconductor device described above, preferably, the photoresist is pressed by the mold until the thickness of the photoresist compressed by the convex portion of the substrate becomes ¼ or less of the wavelength of the irradiation light. Thereby, the photoresist can absorb the energy of irradiation light to the interface with the substrate.
[0067]
In the semiconductor device manufacturing method, the irradiation light is preferably either UV light or excimer light. In this way, it is possible to easily form a fine pattern using UV light and excimer light.
[0068]
Preferably, in the above method for manufacturing a semiconductor device, the mold has a base having a laminated structure of a substrate and a pattern portion, both the substrate and the pattern portion are transparent to irradiation light, and the pattern The refractive index for the irradiated light of the part and the photoresist is equal. As described above, even in the laminated structure of the substrate and the pattern portion, the same effect as that of the single mold base can be obtained.
[0069]
In the method for manufacturing a semiconductor device described above, the step of pressing the mold against the photoresist is performed in a state where the solvent in the photoresist is released by pre-baking the photoresist and the photoresist is heated to the softening point. Thereby, a photoresist can be easily processed with a mold.
[0070]
According to the mold for manufacturing a semiconductor device of the present invention, no residue is generated between patterns by developing after irradiating irradiation light with a photoresist pressed by a mold. For this reason, the etching for removing the residue is unnecessary, and it is possible to prevent the pattern shape deterioration and the dimensional controllability deterioration due to the etching.
[0071]
In addition, by using this mold for manufacturing a semiconductor device, a photoresist can be used in place of the photocurable resin, so that pattern shrinkage does not occur as in the case of using the photocurable resin.
[0072]
In the above mold for manufacturing a semiconductor device, the substrate is transparent to the irradiation light applied to the photoresist. As a result, it is possible to irradiate the photoresist with irradiation light in a state where the mold is pressed against the photoresist.
[0073]
In the above-mentioned mold for manufacturing a semiconductor device, the refractive index with respect to the irradiation light of the substrate is preferably equal to the refractive index with respect to the irradiation light of the photoresist. This eliminates the optical interface at the boundary surface between the mold and the photoresist, so that the pattern can be easily shaped even if the pattern size is equal to or smaller than the wavelength of the irradiation light. Therefore, formation of a fine pattern becomes easy.
[Brief description of the drawings]
FIG. 1 is a flowchart showing a method of manufacturing a semiconductor device according to a first embodiment of the present invention in the order of steps.
FIG. 2 is a schematic cross sectional view showing the method for manufacturing the semiconductor device in the second embodiment of the present invention.
FIG. 3 is a schematic cross sectional view showing the method for manufacturing the semiconductor device in the third embodiment of the present invention.
FIG. 4 is a basic principle diagram of the nanoimprint lithography technique disclosed in Document 1.
FIG. 5 is a diagram showing another method of the nanoimprint lithography technique disclosed in Document 2.
[Explanation of symbols]
1 mold, 1a substrate, 1a ₁ substrate, 1a ₂ pattern portion, 1b shielding film, 2 a photoresist, 2b protruding portion, 2c recess 3 semiconductor substrate, 7 irradiated light.

Claims (10)

Pressing the mold with the pattern against the photoresist;
Selectively irradiating the photoresist with irradiation light through the mold in a state where the mold is pressed against the photoresist;
Developing the photoresist to remove a region of the photoresist not irradiated with the irradiation light, and patterning the photoresist ,
The mold has a substrate having the pattern made of unevenness on a surface pressed against the photoresist, and a light shielding film that blocks transmission of the irradiation light on a front end surface of the unevenness. Method. The method of manufacturing a semiconductor device according to claim 1, wherein the base is transparent to the irradiation light. 3. The method of manufacturing a semiconductor device according to claim 1, wherein refractive indexes of the base and the photoresist with respect to the irradiation light are equal. To a thickness of the photoresist which has been compressed by the projecting portion of the substrate is less than 1/4 of the wavelength of the irradiated light, characterized in that pressed in the photoresist by the mold, according to claim 1 to 3 A method for manufacturing a semiconductor device according to any one of the above. Characterized in that said irradiation light is either UV light and excimer light, a method of manufacturing a semiconductor device according to any one of claims 1-4. The mold has a base having a laminated structure of a substrate and a pattern portion, both the substrate and the pattern portion are transparent to the irradiation light, and the pattern portion and the photoresist wherein the refractive index with respect to the irradiation light are equal, the method of manufacturing a semiconductor device according to any one of claims 1-5. The step of pressing the mold against the photoresist is performed by pre-baking the photoresist to release the solvent in the photoresist and heating the photoresist to a softening point. The manufacturing method of the semiconductor device in any one of Claims 1-6 . A mold for manufacturing a semiconductor device, which is pressed against the photoresist to form a pattern on the photoresist,
A substrate having a pattern of irregularities on the surface pressed against the photoresist;
A mold for manufacturing a semiconductor device, comprising: a light-shielding film that blocks transmission of the irradiation light on a front end surface of the convex portion of the irregularities. The mold for manufacturing a semiconductor device according to claim 8 , wherein the substrate is transparent to irradiation light applied to the photoresist. Characterized in that said refractive index with respect to the irradiation light is equal to the refractive index with respect to the irradiation light of the photoresist, molding for semiconductor device fabrication according to claim 8 or 9 of the base body.

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