JP2004241581A - Alignment method, alignment equipment, exposure equipment, and method for manufacturing semiconductor device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an alignment method and an alignment equipment which increase strength of an image in which the alignment mark of a wafer is picturized and can increase alignment precision, exposure equipment using the alignment method and the alignment equipment; and to provide a method for manufacturing a semiconductor device. <P>SOLUTION: The resist film of a wafer 22 and a mask 14 are held with a prescribed distance. Radiation of light LT<SB>1</SB>which has wavelength excluding region in which the resist film is exposed and performs plane polarization like p-polarized light is performed to an alignment mark for the wafer of the wafer through the mask from a direction which is slanted to the main surface of the wafer. Radiation is also performed to an alignment mark for the mask. Reflected light in the wafer and a reflected light (return light LT<SB>R</SB>) in the mask are received. Deviation of the alignment mark for the mask to the alignment mark of the wafer is detected, and alignment is performed by adjusting the position of the mask with respect to the wafer in accordance with the detected deviation. <P>COPYRIGHT: (C)2004,JPO&NCIPI

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to an alignment method and an alignment apparatus for a mask used in a lithography process of manufacturing a semiconductor device, an exposure apparatus using the same, and a method for manufacturing a semiconductor device.
[0002]
[Prior art]
As a next-generation exposure technology that replaces photolithography, transfer-type exposure methods, such as electron beam proximity lithography and 1: 1 X-ray lithography, have been developed in which a mask is brought close to the wafer to be exposed using electron beams or X-rays. ing.
A mask used in these lithography is composed of a 0.5 μm-thick Si film, a SiC film, or a thin film such as diamond.
[0003]
In the above-mentioned next-generation exposure technology, for example, an alignment device that measures and positions the relative position between a mask and a wafer to be exposed in real time is used (see Patent Documents 1 to 3).
The above-described alignment apparatus is, for example, an alignment optical system using long-wavelength light that does not expose a resist film formed on a wafer to be exposed, and a measurement light (illumination) is applied to an alignment mark written on a mask and a wafer. Irradiates light, and detects the light scattered and returned by each alignment mark to form an image on an image sensor, performs image processing, measures the position of the alignment mark, and detects a positional shift between the mask and the wafer. .
The position of the mask with respect to the wafer is adjusted and adjusted so as to correct the misalignment between the mask and the wafer obtained as described above.
[0004]
In order to prevent the alignment optical system from interfering with the exposure electron beam (EB), the exposure X-ray, those optical systems, a mask, a mask stage, a wafer stage, etc., the alignment optical system emits measurement light (illumination light). It is installed so as to be obliquely incident on the surface of the wafer.
[0005]
In the above alignment apparatus, the illumination light incident on the wafer is transmitted through the mask and reaches the wafer, and the scattered light returning from the wafer is also transmitted through the mask.
[0006]
[Patent Document 1]
Japanese Patent No. 2955668
[Patent Document 2]
Japanese Patent No. 3048904
[Patent Document 3]
Japanese Patent No. 3235782
[0007]
[Problems to be solved by the invention]
However, in the alignment apparatus having the above-described alignment optical system, the illumination light incident on the wafer is transmitted through the mask and reaches the wafer, and the illumination light incident on the mask is exposed on the upper surface of the thin film forming the mask. Since the light is repeatedly reflected on the lower surface and attenuated by multi-wave interference that interferes with each other, the intensity of the illumination light actually incident on the wafer decreases.
In addition, the illumination light that has reached the alignment mark on the wafer is scattered at the alignment mark, and even on the optical axis detected as return light, the presence of the mask causes repeated reflection on the lower surface and the upper surface of the thin film constituting the mask. The light is attenuated due to multi-wave interference, and the intensity of light actually detected as return light decreases.
[0008]
As described above, the intensity of the image of the alignment mark of the wafer is smaller than that of the image of the alignment mark of the mask, and the detection error of the alignment mark of the wafer is relatively large.
For this reason, the alignment accuracy is reduced.
[0009]
SUMMARY OF THE INVENTION The present invention has been made in view of the above-described problems. Accordingly, the present invention relates to a transfer type exposure method such as electron beam proximity lithography or 1: 1 X-ray lithography, and particularly to the intensity of an image obtained by imaging an alignment mark on a wafer. It is an object of the present invention to provide an alignment method and an alignment apparatus capable of enhancing alignment accuracy and alignment accuracy, and an exposure apparatus and a semiconductor device manufacturing method using the same.
[0010]
[Means for Solving the Problems]
In order to achieve the above object, a mask alignment method according to the present invention is characterized in that a wafer alignment mark is formed, and a resist film is formed on a wafer on which a resist film is formed on a surface on which the wafer alignment mark is formed. An alignment method for aligning a mask on which a mask alignment mark is formed at a predetermined distance that is equal-size exposure, wherein the step of holding the resist film of the wafer and the mask at the predetermined distance, A linearly polarized light having a wavelength in a region excluding a region where the resist film is exposed is irradiated from a direction oblique to the surface of the wafer to the wafer alignment mark of the wafer through the mask. Irradiating the mask alignment mark of the mask with the light; Receiving the reflected light from the mask and the reflected light from the mask; detecting, from the received reflected light, a displacement of the mask alignment mark of the mask with respect to the alignment mark of the wafer; Adjusting the position of the mask with respect to the wafer to perform alignment.
[0011]
In the mask alignment method of the present invention described above, the resist film on the wafer and the mask are held at a predetermined distance.
Next, a linearly polarized light having a wavelength in a region excluding a region where the resist film is exposed is irradiated to the wafer alignment mark of the wafer through a mask from a direction oblique to the surface of the wafer. Irradiation is performed on the mask alignment mark of the mask.
Next, light reflected by the wafer and light reflected by the mask are received, and a deviation of the mask alignment mark of the mask with respect to the alignment mark of the wafer is detected from the received reflected light.
Next, the position of the mask with respect to the wafer is adjusted and adjusted according to the displacement detected above.
[0012]
In order to achieve the above object, the mask alignment apparatus according to the present invention includes a wafer alignment mark formed on a wafer, and a resist film formed on a surface on which the wafer alignment mark is formed. On the other hand, there is provided an alignment apparatus for aligning a mask on which a mask alignment mark is formed at a predetermined distance for equal magnification exposure, and a holding unit for holding the resist film of the wafer and the mask at the predetermined distance. A light source that emits light having a wavelength in a region excluding a region where the resist film is exposed, a light receiving unit that receives light reflected by the wafer and light reflected by the mask, and From the diagonal direction, the light from the light source is directed to the wafer alignment mark of the wafer through the mask. An optical system that couples the reflected light of the light on the wafer and the reflected light of the mask to the light receiving unit, and irradiates the light onto the alignment mark for mask of the mask, and the received reflected light. A detection unit that detects a shift of the mask alignment mark of the mask with respect to the alignment mark of the wafer, and a position adjustment unit that adjusts the position of the mask with respect to the wafer by the holding unit according to the shift. And at least the light at the time of irradiating the wafer and the mask is linearly polarized light.
[0013]
In the mask alignment apparatus of the present invention, the holding unit holds the resist film on the wafer and the mask at a predetermined distance, and the light source emits light having a wavelength in a region excluding a region where the resist film is exposed.
This light is linearly polarized at least at the time when it is applied to the wafer and the mask, and is directed to the wafer alignment mark of the wafer through the mask from a direction oblique to the surface of the wafer by the optical system. The light is irradiated onto the mask alignment mark of the mask, and the reflected light on the wafer and the reflected light on the mask are coupled to a light receiving unit by an optical system and received.
The detection unit detects the displacement of the mask alignment mark of the mask with respect to the alignment mark of the wafer from the received reflected light, and the position adjustment unit determines the position of the mask with respect to the wafer by the holding unit according to the displacement obtained above. Adjusted.
[0014]
In order to achieve the above object, an exposure apparatus according to the present invention is configured such that a wafer alignment mark is formed, and a resist film is formed on a wafer on which a resist film is formed on a surface on which the wafer alignment mark is formed. An exposure apparatus that includes an alignment unit that aligns a mask on which a mask alignment mark is formed with a predetermined distance that is equal-size exposure, and performs exposure with a predetermined exposure beam. A holding unit that holds the resist film and the mask at the predetermined distance, a light source that emits light having a wavelength in a region other than a region where the resist film is exposed, a reflection of the light on the wafer and a reflection of the light on the mask A light receiving unit for receiving light, and light from the light source passing through the mask from a direction oblique to the surface of the wafer. Irradiating the wafer alignment mark of the wafer with the mask alignment mark of the mask to couple the light reflected by the wafer and the light reflected by the mask to the light receiving portion. An optical system, a detection unit that detects a shift of the mask alignment mark of the mask with respect to the alignment mark of the wafer from the received reflected light, and the mask for the wafer by the holding unit according to the shift. And a position adjustment unit for adjusting the position of the light, and at least the light at the time of irradiation on the wafer and the mask is linearly polarized light.
[0015]
The exposure apparatus of the present invention includes the alignment apparatus of the present invention as an alignment unit for aligning a wafer alignment mark of a wafer and a mask alignment mark of a mask, and performs exposure with a predetermined exposure beam. It is.
[0016]
In order to achieve the above object, a method of manufacturing a semiconductor device according to the present invention includes a method of manufacturing a semiconductor device, comprising: forming a wafer alignment mark on a wafer having a resist film formed on a surface on which the wafer alignment mark is formed; What is claimed is: 1. A method for manufacturing a semiconductor device, comprising: performing pattern exposure using a mask on which an alignment mark and a predetermined pattern are formed, wherein the resist film on the wafer and the mask are held at a predetermined distance for equal exposure. And linearly polarized light having a wavelength in a region excluding a region where the resist film is exposed to light, from a direction oblique to the surface of the wafer, through the mask to the wafer alignment mark of the wafer. Irradiating the wafer with respect to a mask alignment mark of the mask; and irradiating the wafer with the light. Receiving the reflected light and the reflected light from the mask; detecting, from the received reflected light, a displacement of the mask alignment mark of the mask with respect to the alignment mark of the wafer; Adjusting the position of the mask with respect to the wafer to align the mask, and irradiating the wafer with an exposure beam that exposes the resist film to the wafer via the aligned mask. .
[0017]
In the method of manufacturing a semiconductor device according to the present invention described above, the resist film and the mask on the wafer are held at a predetermined distance for equal-size exposure.
Next, a linearly polarized light having a wavelength in a region excluding a region where the resist film is exposed is irradiated to the wafer alignment mark of the wafer through a mask from a direction oblique to the surface of the wafer. Irradiation is performed on the mask alignment mark of the mask.
Next, the light reflected by the wafer and the light reflected by the mask are received, and the displacement of the mask alignment mark of the mask with respect to the alignment mark of the wafer is detected from the received reflected light.
Next, the position of the mask with respect to the wafer is adjusted and aligned according to the displacement.
Next, the wafer is exposed to an exposure beam through which the resist film is exposed through the aligned mask.
[0018]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, an embodiment of a mask alignment method and a mask alignment apparatus according to the present embodiment and an exposure apparatus including the above-described alignment apparatus will be described with reference to the drawings.
[0019]
First embodiment
FIG. 1 is a schematic configuration diagram of an alignment apparatus according to the present embodiment.
In the alignment apparatus of the present embodiment, in order to perform exposure in a transfer type exposure method such as electron beam proximity lithography or equal-size X-ray lithography, a wafer alignment mark is formed, and a resist is formed on a surface on which the wafer alignment mark is formed. Observe the alignment mark for the wafer and the alignment mark for the mask by the epi-illumination system with respect to the resist film of the wafer 22 on which the film is formed. 14 is to be positioned.
When applied to LEEPL (Low Energy Electron-Beam Proximity Projection Lithography), the mask is a stencil mask in which a through hole is formed in a region where a 0.5 μm-thick membrane is subjected to pattern exposure.
[0020]
The alignment apparatus of the present embodiment includes a holder (not shown) for the wafer 22 and the mask 14, a light source 30, a condenser lens 31, a polarizing plate 32, a beam splitter 33, a pupil 34 of an objective lens, an objective lens 35, and an imaging lens 36. , A CCD image sensor 37 and a computer 38.
[0021]
The holding unit (not shown) holds the mask 14 at a distance of about 50 μm with respect to the resist film of the normal wafer 22 so as to perform equal-size exposure, and a mechanism (not shown) moves the mask 14 relative to the wafer. Position can be adjusted.
[0022]
The light source 30 is, for example, an Hg lamp or a Xe lamp, and the illumination light LT is a natural light having a wavelength in a region excluding a region where the resist film formed on the wafer 22 is exposed.₀  Is emitted.
[0023]
Illumination light LT from light source 30₀  Is condensed by the condenser lens 31 and is linearly polarized by the polarizing plate 32, and in particular, p-polarized illumination light LT is applied to the surface of the wafer 22._I  It is said.
Illumination light LT of p polarization_I  Is bent at the spectral plane of the beam splitter 33, passes through the pupil 34 of the objective lens, and is formed by the objective lens 35 on the wafer alignment mark of the wafer 22 from the oblique direction with respect to the surface of the wafer via the mask 14. Irradiation is performed on the mask alignment mark of the mask 14.
The reflected light at the wafer and the reflected light at the mask are the return light LT_R  The beam passes through an objective lens 35, a pupil 34 of the objective lens, and a beam splitter 33, is coupled to a CCD image pickup device 37 serving as a light receiving unit by an imaging lens 36, and a wafer alignment mark of the wafer 22 and a mask Fourteen mask alignment marks are imaged.
[0024]
Image data picked up by the CCD image sensor 37 is subjected to image processing in a detection unit, the positions of the wafer alignment mark of the wafer 22 and the mask alignment mark of the mask 14 are measured, and the positional deviation between the mask and the wafer is detected. Is done.
Further, the position of the mask with respect to the wafer is adjusted and aligned by the position adjustment unit that controls the position of the holding unit (not shown) so as to correct the misalignment between the mask and the wafer obtained as described above. .
The above detection unit and position adjustment unit are realized on the computer 38.
[0025]
As described above, a light source that emits natural light is used as the light source 30 that emits light, and the polarizing plate 32 is included as an optical system that irradiates the light to the wafer alignment mark of the wafer 22 and the mask alignment mark of the mask. By using the optical system, at least the light at the time of irradiating the wafer 22 and the mask 14 is linearly polarized light, especially p-polarized light with respect to the surface of the wafer 22.
[0026]
The thin film (membrane) constituting the mask is made of a thin film of Si, SiC, diamond, or the like. Since the optical system is inclined and the illumination light is obliquely incident on the wafer, the illumination light changes depending on the polarization direction.
A simulation was performed in consideration of the fact that the illumination light from the objective lens and the scattered light at the alignment mark were spherical waves, and it was found that the transmittance of p-polarized light was higher than that of s-polarized light.
This result will be described in an example described later.
[0027]
According to the alignment apparatus according to the present embodiment, by using p-polarized light for the surface of the wafer 22 as the illumination light, it is possible to increase the transmittance of the mask as compared with the case where conventional natural light is used. The intensity of the illuminating light that reaches can be increased relative to the mask illuminating light, and the intensity of the light detected as the return light can be increased. Accuracy can be improved.
[0028]
Next, an alignment method according to the present embodiment will be described.
First, as shown in FIG. 2A, a silicon thin film (membrane) 12 is formed on a substrate 10 via a silicon oxide film 11, the substrate 10 and the silicon oxide film 11 in the thin film region are removed, and a mask blank is formed. Form. The substrate portion remaining in the region except the thin film region serves as a beam 13 to support the thin film 12.
[0029]
Next, a resist film (not shown) is formed on the thin film 12 of the mask blank, and pattern exposure is performed by, for example, direct X-ray exposure. At this time, the mask alignment mark is also exposed at the same time.
The resist film is developed and etched using the resist film as a mask to form a mask alignment mark 12a and a pattern 12b on the thin film 12, and the resist film is removed.
As described above, the mask 14 which is a stencil mask for LEEPL as shown in FIG. 2B is formed.
[0030]
On the other hand, pattern processing is performed on the surface of the silicon substrate 20 to form a wafer alignment mark 20a, and a resist film 21 is formed thereon.
As described above, the wafer 22 which is the wafer to be exposed as shown in FIG. 2C is formed.
[0031]
Next, the resist film 21 of the wafer 22 and the mask 14 are held at a predetermined distance, and the illumination light LT having a wavelength of a region excluding a region where the resist film is exposed, and being linearly polarized light, particularly p-polarized light._I  Is irradiated to the wafer alignment mark 20a of the wafer 22 via the mask 14 from the direction oblique to the surface of the wafer 22, and to the mask alignment mark 12a of the mask 14.
Next, the reflected light LT on the wafer 22_R  And the reflected light from the mask 14, and the deviation of the mask alignment mark of the mask from the wafer alignment mark is detected from the received reflected light.
Next, the position of the mask 14 with respect to the wafer 22 is adjusted and aligned according to the deviation obtained above.
[0032]
When exposure is performed subsequent to the above-described alignment, the wafer 22 is exposed to an exposure beam such as an electron beam EB that exposes a resist film to the wafer 22 via the mask 14 positioned as described above. .
[0033]
According to the alignment method according to the present embodiment, p-polarized light is used for the surface of the wafer 22 as the illumination light, and the intensity of the illumination light reaching the wafer is more relative to the mask illumination light than conventional natural light. In addition, the intensity of light detected as return light can be increased, the detection error of the alignment mark on the wafer becomes smaller than that of natural light illumination, and the alignment accuracy can be improved.
[0034]
(Example)
Considering that the illumination light from the objective lens and the scattered light from the alignment mark are spherical waves, a 0.5 μm Si film is assumed as the thin film constituting the mask, and the light is focused by the objective lens with a numerical aperture of 0.35. In this case, the wavelength dependence of the transmittance of the thin film was simulated separately for p-polarized light and s-polarized light.
The results are shown in FIGS. 4 (a) and 4 (b). These correspond to p-polarized light and s-polarized light, respectively.
As described above, in each of the drawings, the reflected light on the front and back surfaces of the thin film of the mask interferes with each other, so that the transmittance of the thin film periodically changes depending on the wavelength, and also changes depending on the polarization direction. It was found that the transmittance was higher than that of polarized light.
[0035]
Second embodiment
The present embodiment is substantially the same alignment method and alignment apparatus as the first embodiment, but differs greatly in that a semiconductor laser that emits linearly polarized light is used as a light source.
[0036]
FIG. 5 is a schematic configuration diagram of the alignment apparatus according to the present embodiment.
The alignment apparatus according to the present embodiment includes a holding unit (not shown) for the wafer 22 and the mask 14, a light source (semiconductor laser) 40, a polarization plane holding fiber 41, a fiber emitting unit 42, a condenser lens 43, a half-wave plate 44, It has a beam splitter 45, an objective lens pupil 46, an objective lens 47, an imaging lens 48, a CCD image sensor 49, and a computer 50.
[0037]
The holding unit (not shown) holds the mask 14 at a distance of about 50 μm with respect to the resist film of the wafer 22 so as to achieve the same-size exposure, and a mechanism (not shown) moves the mask 14 relative to the wafer. Position can be adjusted.
[0038]
The light source (semiconductor laser) 40 is illumination light LT that is linearly polarized light having a wavelength in a region other than a region where the resist film formed on the wafer 22 is exposed.₀  Is emitted.
[0039]
Illumination light LT from light source 40_I  Is transmitted while maintaining linearly polarized light by the polarization maintaining fiber 41, emitted from the fiber emitting section 42, condensed by the condenser lens 43, and the polarization direction is adjusted by rotating the half-wave plate 44.
Further, the illumination light LT_I  Is bent on the spectral surface of the beam splitter 45, passes through the pupil 46 of the objective lens, and is applied to the wafer alignment mark of the wafer 22 via the mask 14 from the oblique direction with respect to the surface of the wafer by the objective lens 47. Irradiation is performed on the mask alignment mark of the mask 14.
Here, the illumination light LT_I  The half-wave plate 44 is adjusted so that the polarization direction becomes p-polarized with respect to the surface of the wafer 22.
The reflected light at the wafer and the reflected light at the mask are the return light LT_R  The beam passes through an objective lens 47, a pupil 46 of the objective lens, and a beam splitter 45, is coupled to a CCD image pickup device 49 as a light receiving unit by an image forming lens 48, and has a wafer alignment mark and a mask of the wafer 22. Fourteen mask alignment marks are imaged.
[0040]
Image data picked up by the CCD image sensor 49 is subjected to image processing in a detection unit, the positions of the wafer alignment mark of the wafer 22 and the mask alignment mark of the mask 14 are measured, and the positional deviation between the mask and the wafer is detected. Is done.
Further, the position of the mask with respect to the wafer is adjusted and aligned by the position adjustment unit that controls the position of the holding unit (not shown) so as to correct the misalignment between the mask and the wafer obtained as described above. .
The detection unit and the position adjustment unit described above are implemented on the computer 50.
[0041]
According to the alignment apparatus according to the present embodiment, as in the first embodiment, by using p-polarized light for the surface of the wafer 22 as the illumination light, the transmittance of the mask is increased as compared with the case where conventional natural light is used. Therefore, the intensity of the illumination light reaching the wafer can be increased relative to the mask illumination light, and the intensity of the light detected as the return light can be increased. Is relatively small, and alignment accuracy can be improved.
[0042]
Third embodiment
This embodiment is an exposure apparatus provided with the alignment devices according to the first and second embodiments.
FIG. 6 is a schematic view of an exposure apparatus used for LEEPL.
This exposure apparatus has an electron gun 60, an aperture 61, a condenser lens 62, a pair of main deflectors (63, 64), and a pair of fine adjustment deflectors (65, 66).
[0043]
The diameter of the electron beam EB emitted from the electron gun 60 is limited by an aperture 61 and is converted into a parallel beam by a condenser lens 62.
The main deflectors (63, 64) deflect the electron beam EB so that the electron beam EB is perpendicularly incident on the mask 14 while being parallel.
The electron beam EB is incident on the stencil mask 14 in either the raster or vector scanning mode. In either case, the main deflector (63, 64) is used to deflect the electron beam EB. The fine adjustment deflectors (65, 66) further finely adjust the electron beam EB deflected by the main deflectors (63, 64).
The electron beam EB transmitted through the stencil mask 47 is irradiated on a resist film for electron beam exposure formed on the wafer 22, and is subjected to pattern exposure.
[0044]
Here, the exposure apparatus according to the present embodiment includes an alignment device 70.
The alignment device 70 has the same configuration as the alignment devices according to the first and second embodiments.
That is, the linearly polarized illumination light LT has a wavelength in a region excluding a region where the resist film is exposed._I  Is irradiated to the wafer alignment mark of the wafer 22 via the mask 14 and to the mask alignment mark of the mask 14 from a direction oblique to the surface of the wafer 22.
Further, the reflected light on the wafer 22 and the reflected light on the mask 14 are received, and from the received reflected light, a shift of the mask alignment mark of the mask 14 with respect to the alignment mark of the wafer 22 is detected. The position of the mask 14 with respect to the wafer 22 is adjusted and aligned.
The exposure apparatus of this embodiment can perform exposure after the position of the mask 14 with respect to the wafer 22 is adjusted with high precision as described above.
[0045]
The alignment method, alignment apparatus, and exposure apparatus of the present invention are not limited to the above embodiments.
For example, in the present embodiment, the stencil mask alignment method has been described. However, the present invention is applied to a mask alignment method for each next-generation exposure technology by applying a mask manufacturing process known from various papers and patents. it can.
Further, the alignment method and apparatus of the present invention can be applied as a method and apparatus for aligning a mask for pattern exposure in a method of manufacturing a semiconductor device having a step of performing pattern exposure on a wafer to be exposed.
In addition, various changes can be made without departing from the spirit of the present invention.
[0046]
【The invention's effect】
According to the alignment method of the present invention, linearly polarized light (particularly, p-polarized light) is used as the illumination light with respect to the surface of the wafer, and the intensity of the illumination light reaching the wafer is smaller than that of the conventional natural light with respect to the mask illumination light. The intensity of the light detected as return light can be relatively increased, and the detection error of the alignment mark on the wafer can be relatively reduced, so that the alignment accuracy can be improved.
[0047]
According to the alignment apparatus of the present invention, by using linearly polarized light (particularly, p-polarized light) as the illumination light with respect to the surface of the wafer, the transmittance of the mask can be increased as compared with the case where conventional natural light is used. The intensity of the illuminating light reaching the wafer can be relatively increased with respect to the mask illuminating light, and the intensity of the light detected as return light can be increased, so that the detection error of the alignment mark on the wafer becomes relatively small. The alignment accuracy can be improved.
[0048]
According to the exposure apparatus of the present invention, exposure can be performed after the position of the mask with respect to the wafer is adjusted with high accuracy by the alignment apparatus of the present invention.
[0049]
According to the method of manufacturing a semiconductor device of the present invention, the alignment device of the present invention can be used to manufacture a semiconductor device by exposing a mask position with respect to a wafer with high accuracy.
[Brief description of the drawings]
FIG. 1 is a schematic configuration diagram of an alignment device according to a first embodiment.
FIGS. 2A to 2C are cross-sectional views illustrating steps of an alignment method according to the first embodiment.
FIGS. 3A and 3B are cross-sectional views illustrating steps of an alignment method according to the first embodiment.
FIGS. 4A and 4B show the results of a transmittance simulation according to an example.
FIG. 5 is a schematic configuration diagram of an alignment device according to a second embodiment.
FIG. 6 is a schematic configuration diagram of an exposure apparatus according to a third embodiment.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 10 ... board | substrate, 11 ... silicon oxide film, 12 ... thin film (membrane), 13 ... beam, 14 ... mask, 20 ... silicon substrate, 21 ... resist film, 22 ... wafer, 30 ... light source, 31 ... condenser lens, 32 ... Polarizing plate, 33: beam splitter, 34: pupil of objective lens, 35: objective lens, 36: imaging lens, 37: CCD imaging device, 38: computer, 40: light source (semiconductor laser), 41: polarization plane maintaining fiber Reference numeral 42 denotes a fiber emission unit 43 reference numeral 43 denotes a condenser lens 44 denotes a half-wave plate 45 denotes a beam splitter 46 denotes a pupil of an objective lens 47 denotes an objective lens 48 denotes an imaging lens 49 denotes a CCD image pickup device 50 ... Computer, 60 ... Electron gun, 61 ... Aperture, 62 ... Condenser lens, 63,64 ... A pair of main deflectors, 65,66 ... A pair Fine adjustment deflector, 70 ... alignment apparatus, LT₀  ... Natural illumination light, LT_I  … Illumination light, LT_R  …reflected light.

Claims (10)

A wafer alignment mark is formed, and a mask alignment mark is formed at a predetermined distance for equal exposure to the resist film of a wafer having a resist film formed on a surface on which the wafer alignment mark is formed. An alignment method for positioning the mask,
Holding the resist film of the wafer and the mask at the predetermined distance,
The linearly polarized light having a wavelength in a region excluding a region where the resist film is exposed is irradiated from a direction oblique to the surface of the wafer through the mask to the wafer alignment mark of the wafer. Irradiating, and irradiating the mask alignment mark of the mask,
Receiving the reflected light of the light on the wafer and the reflected light of the mask,
Detecting a shift of the mask alignment mark of the mask with respect to the alignment mark of the wafer from the received reflected light;
Adjusting the position of the mask with respect to the wafer in accordance with the displacement to perform alignment. 2. The alignment method according to claim 1, wherein the linearly polarized light is p-polarized with respect to the surface of the wafer. Using a light source that emits natural light as a light source that emits the light,
2. The alignment method according to claim 1, wherein an optical system including a polarizing plate is used as an optical system that irradiates the light to the wafer alignment mark of the wafer and the mask alignment mark of the mask. The alignment method according to claim 1, wherein a laser that emits linearly polarized light is used as the light source that emits the light. A wafer alignment mark is formed, and a mask alignment mark is formed at a predetermined distance for equal exposure to the resist film of a wafer having a resist film formed on a surface on which the wafer alignment mark is formed. An alignment device for positioning the mask,
A holding unit for holding the resist film and the mask of the wafer at the predetermined distance,
A light source that emits light having a wavelength in a region excluding a region where the resist film is exposed,
A light receiving unit that receives the light reflected by the wafer and the light reflected by the mask,
From a direction oblique to the surface of the wafer, irradiate the light from the light source to the wafer alignment mark of the wafer through the mask, and irradiate the mask alignment mark of the mask, An optical system that couples the light reflected by the wafer and the light reflected by the mask to the light receiving unit,
From the received reflected light, a detection unit that detects a shift of the mask alignment mark of the mask with respect to the alignment mark of the wafer,
A position adjustment unit that adjusts the position of the mask with respect to the wafer by the holding unit according to the displacement,
An alignment apparatus wherein at least the light at the time of irradiating the wafer and the mask is linearly polarized. The alignment apparatus according to claim 5, wherein the linearly polarized light is p-polarized with respect to the surface of the wafer. The light source is a light source that emits natural light,
6. The alignment apparatus according to claim 5, wherein the optical system includes a polarizing plate until the light from the light source is applied to the wafer alignment mark of the wafer and the mask alignment mark of the mask. The alignment device according to claim 5, wherein the light source is a laser that emits linearly polarized light. A wafer alignment mark is formed, and a mask alignment mark is formed at a predetermined distance for equal exposure to the resist film of a wafer having a resist film formed on a surface on which the wafer alignment mark is formed. An exposure apparatus that includes an alignment unit that aligns the mask, and performs exposure with a predetermined exposure beam.
The alignment unit includes:
A holding unit for holding the resist film and the mask of the wafer at the predetermined distance,
A light source that emits light having a wavelength in a region excluding a region where the resist film is exposed,
A light receiving unit that receives the light reflected by the wafer and the light reflected by the mask,
From a direction oblique to the surface of the wafer, irradiate the light from the light source to the wafer alignment mark of the wafer through the mask, and irradiate the mask alignment mark of the mask, An optical system that couples the light reflected by the wafer and the light reflected by the mask to the light receiving unit,
From the received reflected light, a detection unit that detects a shift of the mask alignment mark of the mask with respect to the alignment mark of the wafer,
A position adjustment unit that adjusts the position of the mask with respect to the wafer by the holding unit according to the displacement,
An exposure apparatus wherein at least the light at the time of irradiating the wafer and the mask is linearly polarized. Pattern exposure using a mask on which a mask alignment mark and a predetermined pattern are formed on a wafer on which a wafer alignment mark is formed and a resist film is formed on a surface on which the wafer alignment mark is formed. A method for manufacturing a semiconductor device, comprising:
A step of holding the resist film and the mask of the wafer at a predetermined distance that is equal exposure,
The linearly polarized light having a wavelength in a region excluding a region where the resist film is exposed is irradiated from a direction oblique to the surface of the wafer through the mask to the wafer alignment mark of the wafer. Irradiating, and irradiating the mask alignment mark of the mask,
Receiving the reflected light of the light on the wafer and the reflected light of the mask,
Detecting a shift of the mask alignment mark of the mask with respect to the alignment mark of the wafer from the received reflected light;
Adjusting the position of the mask with respect to the wafer in accordance with the displacement to perform alignment;
Irradiating the wafer with an exposure beam that exposes the resist film to the wafer via the aligned mask.

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