JP2004241575A - Pattern forming method and equipment therefor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To form a resist pattern of nano metric size with high precision. <P>SOLUTION: In the pattern forming method, a first resist pattern is formed by performing exposure and development to a resist film and scanned with an electron beam, generated secondary electrons are detected, and a secondary electron image of the first resist pattern is acquired (step SA1). Next, on the basis of the secondary electron image and desired pattern dimension, an etching region as a region wherein the first resist pattern should be eliminated by etching is computed (step SA2). Then the etching region is irradiated with an electron beam while gas containing oxygen atoms is supplied to the surface of the first resist pattern, and a second resist pattern whose width is narrower than that of the first resist pattern is formed (step SA3). <P>COPYRIGHT: (C)2004,JPO&NCIPI

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a lithography technique used in a manufacturing process of a semiconductor integrated circuit device.
[0002]
[Prior art]
In recent years, as semiconductor integrated circuits have become more highly integrated, circuit patterns have become finer, and improvements in the resolution of photolithography have been demanded. In photolithography, the wavelength of an exposure light source has been shortened, and lithography using an ArF excimer laser having a wavelength of 193 nm has provided a resolution of about 100 nm, which is about half the wavelength.
[0003]
It is well known that high resolution can be obtained by using an electron beam exposure method, but the limit is to obtain a resolution of about 10 nm or more. This means that the electron beam can be narrowed down to a beam diameter of 1 nm or less, but since the resolution is determined by the molecular size of the resist, obtaining a resolution of over 10 nm is the limit.
[0004]
Recently, various slimming methods for narrowing the resist pattern after exposure and development have been proposed in order to further reduce the size of the resist pattern. For example, as shown in Patent Document 1, there is a method of narrowing a resist pattern by isotropic etching using ozone. Also, as shown in Patent Document 2, there is a method of narrowing a resist pattern by ashing with ozone while irradiating UV light. Patent Document 2 discloses a method of locally irradiating UV light to perform ashing.
[0005]
[Patent Document 1]
JP 2002-231608 A
[Patent Document 2]
JP 2001-85407 A
[Non-patent literature]
Introduction to ultra-fine processing, co-authored by Shizujiro Furukawa and Tanemasa Asano, pp. 164-171
[0006]
[Problems to be solved by the invention]
However, in such a pattern forming method, after forming a resist pattern by photolithography, the resist pattern is narrowed, but it has been difficult to obtain a resist pattern having a dimension of 10 nm or less with sub-nanometer accuracy.
[0007]
In a method of narrowing a resist pattern by isotropic etching using ozone, it is considered that the limit is to reduce a resist pattern formed by photolithography to 70% of its dimension. Further, if the etching is further performed, the shape of the resist pattern deteriorates, and a problem arises in that the accuracy of the shape of the resist pattern decreases.
[0008]
In the method of locally irradiating the resist pattern with UV light, the beam diameter of the UV light is limited to about half of the wavelength of the light source to be used. The limit is about 10 nm. In addition, since etching using ozone is performed, a portion that is not irradiated with UV light is slightly etched, so that the shape of the resist pattern slightly deteriorates.
[0009]
As described above, with the conventional resist pattern slimming method, it is difficult to form a nanometer-sized resist pattern, and it is necessary to form a resist pattern with high precision without causing deterioration in the shape of the resist pattern. Is difficult.
[0010]
An object of the present invention is to solve the above-mentioned problems at once, and an object of the present invention is to obtain a nanometer-sized resist pattern with high accuracy.
[0011]
[Means for Solving the Problems]
In order to achieve the above object, a pattern forming method according to the present invention includes a first step of exposing and developing a resist film to form a first resist pattern; And a second step of acquiring a secondary electron image of the first resist pattern by detecting the generated secondary electrons. The first step is performed based on the secondary electron image and a desired pattern size. A third step of calculating an etching area which is an area where the resist pattern is to be removed by etching, and irradiating the etching area with an electron beam while supplying a gas containing oxygen atoms to a surface of the first resist pattern. And forming a second resist pattern having a width smaller than that of the first resist pattern.
[0012]
According to the pattern forming method of the present invention, since the etching region is irradiated with the electron beam while supplying a gas containing oxygen atoms to the first resist pattern, the resist material is applied only to the electron beam irradiation portion in the first resist pattern. Oxidation and decomposition proceed to perform etching. Therefore, the first resist pattern can be slimmed to form a second resist pattern having a nanometer size. Further, since the etching area of the first resist pattern is obtained based on the secondary electron image of the first resist pattern and the desired pattern size, the shape of the first resist pattern is slimmed with high precision to obtain the second resist pattern. A resist pattern can be formed.
[0013]
In the pattern forming method of the present invention, the third step compares the data of the secondary electron image acquired in the first step with the design pattern data obtained based on the desired pattern size, and It is preferable to include a step of calculating a difference area between the data and the design pattern data as an etching area.
[0014]
By doing so, the accuracy of the etched region is improved, so that a highly accurate second resist pattern can be formed.
[0015]
In the pattern forming method of the present invention, it is preferable that the fourth step includes a step of irradiating the etching region with an electron beam shaped into a rectangular shape.
[0016]
By doing so, the speed of removing the etching region of the first resist pattern can be increased.
[0017]
In the pattern forming method of the present invention, in the fourth step, it is preferable that the electron beam focused in a spot shape is scanned over the etching region.
[0018]
By doing so, the dimensional accuracy when etching the first resist pattern is increased.
[0019]
In the pattern forming method of the present invention, it is preferable that the fourth step includes a step of scanning the electron beam focused in a spot shape in parallel with a side surface of the first resist pattern with respect to the etching region.
[0020]
By doing so, the roughness of the side wall of the second resist pattern can be reduced.
[0021]
A pattern forming apparatus according to the present invention includes a unit for emitting an electron beam, and a secondary electron generated by scanning an electron beam on a first resist pattern formed by exposing and developing a resist film. Means for acquiring a secondary electron image of the first resist pattern by detecting the first resist pattern, and etching the region where the first resist pattern should be removed by etching based on the secondary electron image and the desired pattern size. A third step of calculating an area, a means for supplying a gas containing oxygen atoms to the surface of the first resist pattern, and a third step having a width smaller than that of the first resist pattern by irradiating the etching area with an electron beam. Means for forming a second resist pattern.
[0022]
According to the pattern forming apparatus of the present invention, an electron beam is irradiated to an etching region while supplying a gas containing oxygen atoms to the first resist pattern. Oxidation and decomposition proceed to perform etching. Therefore, the first resist pattern can be slimmed to form a second resist pattern having a nanometer size. Further, since the etching area of the first resist pattern is obtained based on the secondary electron image of the first resist pattern and the desired pattern size, the shape of the first resist pattern is slimmed with high precision to obtain the second resist pattern. A resist pattern can be formed.
[0023]
In the pattern forming apparatus of the present invention, it is preferable that the means for supplying a gas containing oxygen atoms has a gas supply nozzle having an injection port at a position at a distance of 10 cm or less from the first resist pattern.
[0024]
This makes it possible to efficiently supply the first resist pattern with a gas containing oxygen necessary for accurately performing etching by oxidation and decomposition of the resist material without waste.
[0025]
BEST MODE FOR CARRYING OUT THE INVENTION
(1st Embodiment)
First, an outline of a pattern forming method according to a first embodiment of the present invention will be described with reference to FIG.
[0026]
As shown in step ST1, a chemically amplified resist is spin-coated on the semiconductor substrate to form a coating film. Then, as shown in step ST2, the coating film is pre-baked to have a thickness of about 100 nm. Is formed. Next, as shown in step ST3, pattern exposure is performed on the resist film by a reduced projection exposure method using an ArF excimer laser or the like, and then, as shown in step ST4, the pattern-exposed resist film is exposed. After baking. Next, as shown in step ST5, development using an alkaline developer is performed to form a first resist pattern. Next, as shown in step ST6, by slimming the first resist pattern using an electron beam, a second resist pattern having a smaller width than the first resist pattern is formed.
[0027]
Hereinafter, the pattern forming apparatus according to the first embodiment of the present invention used in step ST6 will be described.
[0028]
As shown in FIG. 2, the pattern forming apparatus includes a vacuum chamber 100, and a sample stage 102 that holds a semiconductor substrate 101 on which a first resist pattern is formed is provided at the bottom of the vacuum chamber 100. I have. An oxygen supply nozzle 105 for introducing oxygen gas supplied from an oxygen cylinder 103 to the surface of the first resist pattern via a flow path opening / closing valve 104 is provided below the vacuum chamber 100. Are provided in the vicinity of the first resist pattern. A diffusion pump 106 is provided below the vacuum chamber 100. The diffusion pump 106 reduces the pressure in the vacuum chamber 100 to a desired pressure.
[0029]
At the top of the vacuum chamber 100, an electron gun 107 for emitting an electron beam having a beam diameter of 1 nm or less is provided. A blanking system 108 for switching the electron beam emitted from the electron gun 107 and an electron beam emitted from the electron gun 107 are two-dimensionally scanned on the first resist pattern in the upper part of the vacuum chamber 100. And a deflecting system 109 for causing the light to flow. Further, below the vacuum chamber 100, a secondary electron detection system 110 for detecting secondary electrons generated from the first resist pattern is provided. The blanking system 108, the deflection system 109, and the secondary electron detection system 110 are controlled by a computer 112 via an interface 111.
[0030]
The electron beam emitted from the electron gun 107 is scanned on the first resist pattern by the deflection system 109, and secondary electrons generated from the first resist pattern are detected by the secondary electron detection system 110. The signal of the secondary electrons detected by the secondary electron detection system 110 is input to the computer 112, and the computer 112 processes the detection signal to obtain a secondary electron image of the first resist pattern (refer to FIG. Literature "Introduction to Ultrafine Processing, Shizujiro Furukawa and Tanemasa Asano, pp. 164 to 171). Thereafter, based on the position coordinates of the first resist pattern and the desired pattern dimensions, an etching region that is a region where the first resist pattern is to be removed by etching is calculated.
[0031]
Thereafter, while the oxygen supply nozzle 105 supplies oxygen gas to the surface of the first resist pattern, the deflection system 109 irradiates the etching region with an electron beam emitted from the electron gun 107, thereby forming the first resist pattern. A second resist pattern having a smaller width than that is formed. At this time, the distance between the injection port of the oxygen supply nozzle 105 and the first resist pattern formed on the semiconductor substrate 101 is 5 cm, and the oxygen supply nozzle 105 is thus positioned close to the first resist pattern. Since oxygen gas can be sufficiently supplied to the surface of the first resist pattern, the accuracy of removing the resist in the etching region can be improved. The distance between the oxygen supply nozzle 105 and the first resist pattern 11 is not limited to 5 cm, but may be any distance as long as the distance is 10 cm or less and the irradiation of the electron beam is not hindered. Absent. The term “irradiation of the electron beam to the etching region” is a concept including a case where the electron beam focused in a spot shape is irradiated while scanning the etching region.
[0032]
As described above, according to the first embodiment, the position coordinates of the first resist pattern formed by development are calculated by scanning the first resist pattern with an electron beam having a beam diameter of 1 nm or less. Therefore, the position accuracy of irradiating the electron beam while supplying the oxygen gas to the etching region calculated based on the position coordinates and the desired pattern size can be made 1 nm or less. Since the beam diameter of the electron beam for removing the resist in the etching region is also 1 nm or less, a second resist pattern having a size of 10 nm or less can be formed with a dimensional accuracy of 1 nm or less. Further, since the electron beam is irradiated while supplying the oxygen gas to the surface of the first resist pattern, only the resist portion irradiated with the electron beam can be removed, so that the shape of the resist pattern can be reduced and a high aspect ratio can be obtained. A resist pattern can be formed.
[0033]
In the present embodiment, the method of slimming the first resist pattern formed by performing pattern exposure and development on the resist film has been described. Then, slimming may be further performed by applying the present invention.
[0034]
Further, in the present embodiment, the case where the electron beam is irradiated while supplying the oxygen gas to the surface of the first resist pattern has been described, but any gas containing oxygen atoms may be used. That is, the gas containing oxygen atoms is not limited to oxygen gas, ₂ It is a concept including
[0035]
(Second embodiment)
Hereinafter, a second embodiment of the present invention will be described with reference to FIGS.
[0036]
FIG. 3 is a diagram for explaining the electron beam slimming step shown in step ST6 in FIG. 1 referred to in the first embodiment in detail.
[0037]
As shown in step SA1, the first resist pattern obtained by the development is scanned with an electron beam to obtain a secondary electron image of the first resist pattern.
[0038]
Next, as shown in step SA2, the position coordinates of the etching region which is the region to be etched in the secondary electron image of the first resist pattern is calculated so as to have a desired size pattern.
[0039]
Next, as shown in step SA3, by irradiating the etching region with an electron beam while supplying oxygen gas onto the first resist pattern, the second resist pattern is narrower than the first resist pattern. A resist pattern is formed.
[0040]
Hereinafter, the pattern forming method shown in FIG. 3 will be specifically described.
[0041]
A coating film is formed by spin-coating a chemically amplified resist on a semiconductor substrate, and the coating film is pre-baked at 120 ° C. for 60 seconds to form a resist film having a thickness of 100 nm. Next, after pattern exposure is performed on the resist film by a reduction projection exposure apparatus using an ArF excimer laser, the pattern-exposed resist film is baked after exposure at 120 ° C. for 60 seconds. Next, development using an alkaline developer is performed for 60 seconds to form a first resist pattern 11 including a pad portion 11a and a line portion 11b on the semiconductor substrate 201, as shown in FIG.
[0042]
Next, the semiconductor substrate 201 on which the first resist pattern 11 is formed is introduced onto the sample stage 102 in the vacuum chamber 100 of the pattern forming apparatus shown in FIG. By scanning the electron beam emitted from the electron gun 107 on the first resist pattern 11 by the deflection system 109, secondary electrons generated from the first resist pattern 11 are detected by the secondary electron detection system 110. Here, the acceleration voltage of the electron beam is 20 kV, the current is 100 pA, and the beam diameter is 1 nm. Next, the computer 112 acquires a secondary electron image of the first resist pattern 11 based on the detected secondary electrons. The computer 112 obtains the position coordinates of the first resist pattern 11 by further performing image processing on the acquired secondary electron image. As a result, as shown in FIG. 4A, it was calculated that the width of the line portion 11b of the first resist pattern 11 was 102 nm and the width of the pad portion a was 290 nm. Here, when the line portion 11b is reduced to a target width of 8 nm as a desired pattern size, an etching area 11c of the first resist pattern 11 is calculated as shown in FIG. Ask for.
[0043]
Next, while oxygen gas is supplied from the oxygen supply nozzle 105 onto the semiconductor substrate 201 on which the first resist pattern 11 is formed, the entire surface of the etching region 11c of the first resist pattern 11 is uniformly irradiated with the electron beam. As described above, the electron beam emitted from the electron gun 107 is two-dimensionally scanned by the deflection system 109. Here, the acceleration voltage of the electron beam is 20 kV, the current is 100 pA, the beam diameter is 1 nm, and the pressure of oxygen gas is 2 Pa. When the resist film in the etching region 11c is irradiated with the electron beam, the polymer on the surface of the irradiated portion is excited and oxidative decomposition occurs in which the polymer is decomposed by the supplied oxygen gas. That is, only the etching region 11c is etched. As a result, as shown in FIG. 4C, a second resist pattern 12 including a pad portion 12a and a line portion 12b narrower than the line portion 11b of the first resist pattern 11 is formed. You.
[0044]
In particular, as shown in FIG. 5, when removing the etching region 11c of the first resist pattern 11, the direction 11d in which the electron beam is scanned is a direction parallel to the side surface of the line portion 11b of the first resist pattern 11. To Thereby, the roughness of the side wall of the second resist pattern 12 formed after the etching can be reduced. When the scanning of the electron beam onto the etching region 11c is completed, the electron beam is turned off by the blanking system 108, and the introduction of oxygen gas from the oxygen cylinder 103 is stopped by the flow path opening / closing valve 104.
[0045]
As described above, after the first resist pattern 11 is slimmed by etching to form the second resist pattern 12, the electron beam is again scanned on the second resist pattern 12 to form the second resist pattern 12. A secondary electron image was obtained. As a result, it was confirmed that the line width of the second resist pattern 12 after slimming the first resist pattern 11 was 8.3 nm. On the other hand, since the portions not irradiated with the electron beam are not etched because they are not oxidized and decomposed by oxygen gas, the height of the resist in the line portion 12b of the second resist pattern 12 is equal to the film height of the first resist pattern 11. The thickness was kept at 100 nm.
[0046]
As described above, according to the first embodiment, the position coordinates of the first resist pattern formed by development are calculated by scanning the first resist pattern with an electron beam having a beam diameter of 1 nm or less. Therefore, the position accuracy of irradiating the electron beam while supplying the oxygen gas to the etching region calculated based on the position coordinates and the desired pattern size can be made 1 nm or less. Since the beam diameter of the electron beam for removing the resist in the etching region is also 1 nm or less, a second resist pattern having a size of 10 nm or less can be formed with a dimensional accuracy of 1 nm or less. Further, since the electron beam is irradiated while supplying the oxygen gas to the surface of the first resist pattern, only the resist portion irradiated with the electron beam can be removed, so that the shape of the resist pattern can be reduced and a high aspect ratio can be obtained. A resist pattern can be formed.
[0047]
Note that, in the present embodiment, the conditions are described in which the acceleration voltage of the electron beam is 20 kV and the current is 100 pA. However, the acceleration voltage and the current may be any conditions as long as the resolution of the electron beam does not deteriorate to 10 nm or more. Also, the pressure of the oxygen gas may be 1 mPa or more.
[0048]
In addition to the electron beam scanning method described with reference to FIG. 5, the electron beam irradiation method includes, as shown in FIG. 6, an electron beam shaped into a rectangular shape so as to include the etching region 11 c as shown in FIG. 6. Alternatively, one of the etching regions 11c may be etched by fixing and irradiating the irradiation position 11e with a rectangular electron beam. In this case, since the etching is performed by irradiating the etching area 11c with a rectangular electron beam, the processing speed of the etching can be increased. The rectangular electron beam can be shaped by inserting an aperture between the electron gun 107 and the blanking system 108.
[0049]
In the present embodiment, the method of slimming the first resist pattern formed by performing pattern exposure and development on the resist film has been described. Then, slimming may be further performed by applying the present invention.
[0050]
Further, in the present embodiment, the case where the electron beam is irradiated while supplying the oxygen gas to the surface of the first resist pattern has been described, but any gas containing oxygen atoms may be used. That is, the gas containing oxygen atoms is not limited to oxygen gas, ₂ It is a concept including
[0051]
In the present embodiment, the first resist pattern is formed by a reduction projection exposure apparatus using an ArF excimer laser. ₂ An exposure apparatus using a molecular laser, a KrF excimer laser, or an I-ray may be used. Further, pattern exposure using an electron beam may be performed instead of pattern exposure using light.
[0052]
Further, the conditions of the pre-bake for the coating film and the post-exposure bake or development for the pattern-exposed resist film are not limited to the conditions described in the present embodiment.
[0053]
(Third embodiment)
Hereinafter, a third embodiment of the present invention will be described with reference to FIGS.
[0054]
FIG. 7 is a diagram for explaining in detail the slimming step using an electron beam shown in step ST6 in FIG. 1 referred to in the first embodiment.
[0055]
As shown in step SB1, after pattern exposure is performed by a reduced projection exposure method using DUV light or the like, the first resist pattern obtained by development is scanned with an electron beam to form a secondary electron image of the first resist pattern. To get.
[0056]
Next, as shown in step SB2, a difference between the secondary electron image and the design pattern data is obtained by comparing the secondary electron image with design pattern data obtained based on a desired pattern size.
[0057]
Next, as shown in step SB3, an area where the data of the secondary electron image is larger than the design pattern data is set as an etching area to be removed by etching, and its position coordinates are calculated.
[0058]
Next, as shown in step SB4, by irradiating the etching region with an electron beam while supplying oxygen gas onto the first resist pattern, the second resist pattern is narrower than the first resist pattern. A resist pattern is formed.
[0059]
Hereinafter, the pattern forming method shown in FIG. 7 will be specifically described.
[0060]
A chemically amplified resist is spin-coated on a semiconductor substrate to form a coating film, and the coating film is prebaked at 120 ° C. for 60 seconds to form a resist film having a thickness of 70 nm. Next, F ₂ After pattern exposure is performed on the resist film by a reduction projection exposure apparatus using a molecular laser, the pattern-exposed resist film is baked after exposure at 120 ° C. for 60 seconds. Next, the resist film subjected to the post-exposure bake is subjected to development using an alkaline developer for 60 seconds, so that the pad portion 21a and the line portion are formed on the semiconductor substrate 301 as shown in FIG. A first resist pattern 21 of 22b is formed. Next, the semiconductor substrate 301 on which the first resist pattern 21 is formed is introduced onto the sample stage 102 in the vacuum chamber 100 of the pattern forming apparatus shown in FIG. By scanning the electron beam emitted from the electron gun 107 on the first resist pattern 21 by the deflection system 109, secondary electrons generated from the first resist pattern 21 are detected by the secondary electron detection system 110. Here, the acceleration voltage of the electron beam is 2 kV, the current is 100 pA, and the beam diameter is 0.5 nm. Next, the computer 112 acquires a secondary electron image of the first resist pattern 21 based on the detected secondary electrons. The computer 112 obtains the position coordinates of the first resist pattern 21 by further performing image processing of the acquired secondary electron image. As a result, as shown in FIG. 8A, the width of the line portion 21b of the first resist pattern 21 was 70 nm.
[0061]
On the other hand, as shown in FIG. 8B, the width of the line portion 22b of the design pattern data 22 obtained based on the desired pattern size is 5 nm. Therefore, when the difference between the data of the secondary electron image shown in FIG. 8A and the design pattern data shown in FIG. 8B is calculated, difference data 23 is obtained as shown in FIG. 8C. As shown in FIGS. 8A and 8B, since the area indicated by the data of the secondary electron image is larger than the area indicated by the design pattern data, the difference data 23 shown in FIG. And the position coordinates are calculated.
[0062]
Next, while an oxygen gas is supplied from the oxygen supply nozzle 105 onto the semiconductor substrate 301 on which the first resist pattern 21 is formed, the etching region of the first resist pattern 21 is uniformly irradiated with the electron beam. The electron beam emitted from the electron gun 107 is two-dimensionally scanned by the deflection system 109. Here, the acceleration voltage of the electron beam is 2 kV, the current is 100 pA, the beam diameter is 0.5 nm, and the pressure of the oxygen gas is 1 Pa. At this time, when the resist film in the etching region is irradiated with the electron beam, the polymer on the surface of the irradiated portion is excited and oxidative decomposition occurs in which the polymer is decomposed by the supplied oxygen gas. Is etched, ie, only the etched region. As a result, as shown in FIG. 9, a second resist pattern 24 including a pad portion 24a and a line portion 24b having a smaller width than the line portion 21b of the first resist pattern 21 is formed. When the scanning of the electron beam for all the etching regions is completed, the emission of the electron beam is turned off by the blanking system 108, and then the introduction of the oxygen gas is stopped.
[0063]
As described above, after the first resist pattern 21 is slimmed by etching to form the second resist pattern 24, a secondary electron image is obtained by scanning the second resist pattern 24 again with an electron beam. did. As a result, it was confirmed that the line width of the second resist pattern after slimming the first resist pattern 21 was 5 nm. On the other hand, since the portions not irradiated with the electron beam are not etched because they are not oxidized and decomposed by oxygen gas, the height of the resist in the line portions 24b of the second resist pattern 24 is equal to the film height of the first resist pattern 24. It remained at the thickness of 70 nm.
[0064]
As described above, according to the third embodiment, the position coordinates of the first resist pattern formed by development are calculated by scanning the first resist pattern with an electron beam having a beam diameter of 1 nm or less. Therefore, the position accuracy of irradiating the electron beam while supplying oxygen gas to the etching region calculated based on the position coordinates and the design pattern data can be made 1 nm or less. Since the beam diameter of the electron beam for removing the resist in the etching region is also 1 nm or less, a second resist pattern having a size of 10 nm or less can be formed with a dimensional accuracy of 1 nm or less. Further, since the electron beam is irradiated while supplying the oxygen gas to the surface of the first resist pattern, only the resist portion irradiated with the electron beam can be removed, so that the shape of the resist pattern can be reduced and a high aspect ratio can be obtained. A resist pattern can be formed. Further, since the etching region is calculated based on the difference between the data of the secondary electron image of the first resist pattern and the design pattern data, a pattern shape faithful to the design value can be obtained.
[0065]
In this embodiment, the condition that the acceleration voltage of the electron beam is 2 kV and the current is 100 pA is used. However, as long as the resolution of the electron beam does not deteriorate to 10 nm or more, any condition of the acceleration voltage and current may be used. I do not care. Further, the pressure of the oxygen gas may be any pressure as long as it is 1 mPa or more.
[0066]
Further, in the present embodiment, the irradiation of the etching area with the electron beam means that the electron beam focused in a spot shape is irradiated while scanning the etching area, and as described in the second embodiment, The concept includes a case where an electron beam shaped into a rectangle is irradiated on an etching region.
[0067]
In the present embodiment, the method of slimming the first resist pattern formed by performing pattern exposure and development on the resist film has been described. Then, slimming may be further performed by applying the present invention.
[0068]
Further, in the present embodiment, the case where the electron beam is irradiated while supplying the oxygen gas to the surface of the first resist pattern has been described, but any gas containing oxygen atoms may be used. That is, the gas containing oxygen atoms is not limited to oxygen gas, ₂ It is a concept including
[0069]
In the present embodiment, F ₂ In the case where pattern formation is performed by a reduction projection exposure apparatus using a molecular laser, ₂ An exposure apparatus using an ArF excimer laser, a KrF excimer laser, or an I-line other than the molecular laser may be used. Further, pattern exposure using an electron beam may be performed instead of pattern exposure using light.
[0070]
Further, the conditions of the pre-bake for the coating film and the post-exposure bake or development for the pattern-exposed resist film are not limited to the conditions described in the second embodiment.
[0071]
【The invention's effect】
As described above, according to the present invention, since the etching region is irradiated with an electron beam while supplying a gas containing oxygen atoms to the first resist pattern, the resist is only applied to the electron beam irradiation portion in the first resist pattern. Oxidation and decomposition of the material progress and etching is performed. Therefore, the first resist pattern can be slimmed to form a second resist pattern having a nanometer size. Further, since the etching area of the first resist pattern is obtained based on the secondary electron image of the first resist pattern and the desired pattern size, the shape of the first resist pattern is slimmed with high precision to obtain the second resist pattern. A resist pattern can be formed. In this way, a nanometer-sized pattern exceeding the resolution limit due to the diffraction limit of light or the molecular size of the resist can be formed with high precision.
[Brief description of the drawings]
FIG. 1 is a flowchart showing a pattern forming method according to a first embodiment of the present invention.
FIG. 2 is a sectional view showing a pattern forming apparatus according to the first embodiment of the present invention.
FIG. 3 is a view illustrating a pattern forming method according to a second embodiment of the present invention.
FIG. 4A is a plan view illustrating a secondary electron image of a first resist pattern according to a second embodiment of the present invention,
FIG. 4B is a plan view illustrating an etched region of the first resist pattern according to the second embodiment of the present invention,
FIG. 9C is a plan view illustrating a secondary electron image of a second resist pattern according to the second embodiment of the present invention.
FIG. 5 is a plan view illustrating a scanning direction of an electron beam according to a second embodiment of the present invention.
FIG. 6 is a plan view illustrating a method of irradiating a first resist pattern with a rectangular electron beam in a second embodiment of the present invention.
FIG. 7 is a flowchart showing a pattern forming method according to a third embodiment of the present invention.
FIG. 8A is a plan view showing a secondary electron image of a first resist pattern according to a third embodiment of the present invention,
(B) is a plan view showing design pattern data according to the third embodiment of the present invention,
(C) is a plan view showing difference data in the third embodiment of the present invention.
FIG. 9 is a plan view showing a secondary electron image of a second resist pattern according to a third embodiment of the present invention.
[Explanation of symbols]
100 vacuum chamber
101, 201, 301 semiconductor substrate
102 Sample stage
103 oxygen cylinder
104 Flow path open / close valve
105 oxygen supply nozzle
106 Diffusion pump
107 electron gun
108 Blanking system
109 Deflection system
110 Secondary electron detection system
111 interface
112 Computer
11, 21 First resist pattern
12, 24 Second resist pattern
11a, 12a, 21a, 22a, 24a Pad section
11b, 12b, 21b, 22b, 24b Line section
11c Etched area
11d Scanning direction of electron beam
11e Irradiation position
22 Design pattern data
23 Difference data

Claims (7)

A first step of exposing and developing the resist film to form a first resist pattern;
A second step of acquiring a secondary electron image of the first resist pattern by scanning the first resist pattern with an electron beam and detecting generated secondary electrons;
A third step of calculating an etching area that is an area where the first resist pattern is to be removed by etching, based on the secondary electron image and a desired pattern dimension;
Irradiating the etching region with an electron beam while supplying a gas containing oxygen atoms to the surface of the first resist pattern to form a second resist pattern narrower than the first resist pattern; 4. A pattern forming method, comprising: The third step compares the data of the secondary electron image acquired in the first step with design pattern data obtained based on the desired pattern dimension, and compares the data of the secondary electron image with the data of the secondary electron image. 2. The pattern forming method according to claim 1, further comprising a step of calculating a difference area from design pattern data as the etching area. The pattern forming method according to claim 1, wherein the fourth step includes a step of irradiating the etching region with the electron beam shaped into a rectangular shape. 2. The pattern forming method according to claim 1, wherein in the fourth step, the electron beam focused in a spot shape is scanned on the etching region. 5. The method according to claim 4, wherein the fourth step includes a step of scanning the electron beam focused in a spot shape on the etching region in parallel with a side surface of the first resist pattern. 6. Pattern formation method. Means for emitting an electron beam;
By scanning the first resist pattern formed by performing exposure and development on the resist film with the electron beam and detecting the secondary electrons generated, the secondary resist of the first resist pattern is formed. Means for acquiring an electronic image;
Means for calculating an etching area which is an area where the first resist pattern is to be removed by etching, based on the secondary electron image and a desired pattern size;
Means for supplying a gas containing oxygen atoms to the surface of the first resist pattern;
Means for irradiating the etching area with the electron beam to form a second resist pattern having a width smaller than that of the first resist pattern. 7. The gas supply nozzle according to claim 6, wherein the means for supplying the gas containing oxygen atoms has a gas supply nozzle having an injection port at a position at a distance of 10 cm or less from the first resist pattern. Pattern forming equipment.

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