Patent Application
20080246932
1. Field
An example of the present invention relates to an exposure apparatus, device manufacturing method, and exposure method and, particularly, to an exposure apparatus for manufacturing devices such as semiconductor devices, image pickup devices, liquid-crystal display devices, and thin-film magnetic heads by lithography.
2. Description of the Related Art
The photolithography step for manufacturing the semiconductor devices and others is carried out using an exposure apparatus for projecting a pattern image of a mask (or reticle) through a projection optical system onto a photosensitive substrate (wafer or glass plate coated with a photoresist, or the like) to effect exposure thereof. The ordinary exposure apparatus forms one type of pattern in one shot area (unit exposure region) on the photosensitive substrate.
In contrast to it, Japanese Patent Application Laid-open No. 2000-21748 proposes an exposure apparatus of a double exposure type of doubly printing two types of patterns in one shot area on the photosensitive substrate to form a synthetic pattern.
An example of the present invention shows an exposure apparatus of the double exposure type capable of doubly printing, for example, two types of patterns in one shot area on a photosensitive substrate to form a synthetic pattern, based on a relatively compact configuration.
For purposes of summarizing the invention, certain aspects, advantages, and novel features of the invention have been described herein. It is to be understood that not necessarily all such advantages may be achieved in accordance with any particular embodiment of the invention. Thus, the invention may be embodied or carried out in a manner that achieves or optimizes one advantage or group of advantages as taught herein without necessary achieving other advantages as may be taught or suggested herein.
A first embodiment of the present invention provides an exposure apparatus comprising:
a first illumination system which illuminates a first region elongated along a first direction, in a pattern region formed in a first mask;
a second illumination system which illuminates a second region elongated along the first direction, in a pattern region formed in a second mask located apart from the first mask along a second direction perpendicular to the first direction; and
a projection optical system which forms a pattern image of the first region and a pattern image of the second region in parallel along the second direction on a photosensitive substrate, or which forms the pattern image of the first region and the pattern image of the second region in accord with each other on the photosensitive substrate;
wherein an optical axis of an exit-side partial optical system of the first illumination system and an optical axis of an exit-side partial optical system of the second illumination system each are set along a plane parallel to the first direction.
A second embodiment of the present invention provides an exposure apparatus comprising:
a first illumination system which illuminates a first region elongated along a first direction, in a pattern region formed in a first mask;
a second illumination system which illuminates a second region elongated along the first direction, in a pattern region formed in a second mask located apart from the first mask along the first direction; and
a projection optical system which forms a pattern image of the first region and a pattern image of the second region in parallel along a second direction perpendicular to the first direction on a photosensitive substrate, or which forms the pattern image of the first region and the pattern image of the second region in accord with each other on the photosensitive substrate;
wherein an optical axis of an exit-side partial optical system of the first illumination system and an optical axis of an exit-side partial optical system of the second illumination system each are set along a plane parallel to the second direction.
A third embodiment of the present invention provides an exposure apparatus comprising:
a first illumination system which illuminates a first mask;
a second illumination system which illuminates a second mask located apart from the first mask along a first direction; and
a projection optical system which forms a pattern image of the first region and a pattern image of the second region in parallel on a photosensitive substrate, or which forms the pattern image of the first region and the pattern image of the second region in accord with each other on the photosensitive substrate;
wherein an exit-side partial optical system of the first illumination system and an exit-side partial optical system of the second illumination system are arranged next to each other and in parallel, and
wherein an optical axis of the exit-side partial optical system of the first illumination system and an optical axis of the exit-side partial optical system of the second illumination system each are set along a plane parallel to a second direction perpendicular to the first direction.
A fourth embodiment of the present invention provides a device manufacturing method comprising:
an exposure step of using the exposure apparatus of the first embodiment, the second embodiment, or the third embodiment to effect exposure of a pattern of the first mask and a pattern of the second mask on the photosensitive substrate; and
a development step of effecting development of the photosensitive substrate after the exposure step.
A fifth embodiment of the present invention provides an exposure method of using the exposure apparatus of the first embodiment, the second embodiment, or the third embodiment to effect exposure of a pattern of the first mask and a pattern of the second mask on the photosensitive substrate,
wherein, while moving the first mask, the second mask, and the photosensitive substrate along the second direction, scanning exposure of the pattern of the first mask and the pattern of the second mask is effected in a unit exposure region on the photosensitive substrate.
A sixth embodiment of the present invention provides an exposure method of using the exposure apparatus of the first embodiment, the second embodiment, or the third embodiment to effect exposure of a pattern of the first mask and a pattern of the second mask on the photosensitive substrate,
wherein, while moving the first mask, the second mask, and the photosensitive substrate along the second direction, scanning exposure of the pattern of the first mask is effected in one unit exposure region on the photosensitive substrate, and scanning exposure of the pattern of the second mask is effected in another unit exposure region located apart from said one unit exposure region along the second direction.
A seventh embodiment of the present invention provides an illumination apparatus comprising:
a first illumination system which illuminates a first region elongated along a first direction, in a pattern region formed in a first mask; and
a second illumination system which illuminates a second region elongated along the first direction, in a pattern region formed in a second mask located apart from the first mask along a second direction perpendicular to the first direction;
wherein an optical axis of an exit-side partial optical system of the first illumination system and an optical axis of an exit-side partial optical system of the second illumination system each are set along a plane parallel to the first direction, and
wherein the exit-side partial optical system of the first illumination system and the exit-side partial optical system of the second illumination system are arranged next to each other and in parallel.
An eighth embodiment of the present invention provides an illumination apparatus comprising:
a first illumination system which illuminates a first region elongated along a first direction, in a pattern region formed in a first mask; and
a second illumination system which illuminates a second region elongated along the first direction, in a pattern region formed in a second mask located apart from the first mask along the first direction;
wherein an optical axis of an exit-side partial optical system of the first illumination system and an optical axis of an exit-side partial optical system of the second illumination system each are set along a plane parallel to a second direction perpendicular to the first direction, and
wherein the exit-side partial optical system of the first illumination system and the exit-side partial optical system of the second illumination system are arranged next to each other and in parallel.
A ninth embodiment of the present invention provides a device manufacturing method comprising:
an exposure step of using the exposure apparatus of the seventh embodiment or the eighth embodiment to effect exposure of a pattern of the first mask and a pattern of the second mask on the photosensitive substrate; and
a development step of effecting development of the photosensitive substrate after the exposure step.
A general architecture that implements the various features of the invention will now be described with reference to the drawings. The drawings and the associated descriptions are provided to illustrate embodiments of the invention and not to limit the scope of the invention.
Embodiments of the present invention will be described on the basis of the accompanying drawings.
With reference to
The first illumination system ILa (second illumination system ILb) has a light source 1a (1b) for supplying exposure light (illumination light), a first optical system 2a (2b), a fly's eye lens (or micro fly's eye lens) 3a (3b), and a second optical system 4a (4b). The light source 1a (1b) applicable herein is, for example, an ArF excimer laser light source for supplying light having the wavelength of about 193 nm, or a KrF excimer laser light source for supplying light having the wavelength of about 248 nm.
A nearly parallel beam emitted from the light source 1a (1b) travels through the first optical system 2a (2b) to enter the fly's eye lens 3a (3b). The first optical system 2a (2b) has, for example, a beam transmitting system (not shown) having a well-known configuration, and a polarization state varying part (not shown). The beam transmitting system has functions of guiding the beam to the polarization state varying part while converting the incident beam into a beam having a cross section of an appropriate size and shape, and actively correcting positional variation and angular variation of the beam incident to the polarization state varying part.
The polarization state varying part has a function of varying a polarization state of the illumination light incident to the fly's eye lens 3a (3b). Specifically, the polarization state varying part is composed, for example, of the following components in order from the light source side: a half wave plate made of rock crystal, an angle-deviation prism of rock crystal or rock-crystal prism, and an angle-deviation prism of silica glass or silica prism. Each of the half wave plate, rock-crystal prism, and silica prism is arranged to be rotatable around the optical axis AXa (AXb). The rock-crystal prism has a depolarizing action and the silica prism has a function of correcting curvature of rays due to the angle-deviation action of the rock-crystal prism.
As the direction of the crystallographic axis of the half wave plate and the direction of the crystallographic axis of the rock-crystal prism are appropriately set, the polarization state varying part converts linearly polarized light coming from the beam transmitting system, into linearly polarized light having a different vibration direction, converts the incident linearly polarized light into unpolarized light, or directly outputs the incident linearly polarized light without conversion. After the polarization state is varied according to need by the polarization state varying part, the beam is then incident to the fly's eye lens 3a (3b). The polarization state varying part applicable herein is, for example, one of those disclosed in Published U.S. Pat. Applications No. 2006/0055834, No. 2006/0171138, and No. 2006/0170901.
The beam entering the fly's eye lens 3a (3b) is two-dimensionally split by a large number of small lens elements to form small light sources on rear focal planes of the respective small lens elements into which the beam is incident. In this way, a substantial surface illuminant consisting of a large number of small light sources is formed on the rear focal plane of the fly's eye lens 3a (3b). Beams from the fly's eye lens 3a (3b) are guided via the second optical system 4a (4b) to a first mask Ma (second mask Mb).
The second optical system 4a (4b) has, for example, a condenser optical system (not shown) having a well-known configuration, a mask blind (not shown), an imaging optical system (not shown), a path-folding reflector 4aa (4ba) as a folding member, and so on. In this case, the beams from the fly's eye lens 3a (3b) travel through the condenser optical system and thereafter illuminate the mask blind in a superimposed manner. An illumination field of a rectangular shape according to the shape of each small lens element forming the fly's eye lens 3a (3b) is formed on the mask blind as an illumination field stop.
After passing through a rectangular aperture (optically transparent part) of the mask blind, the beams then travel via the imaging optical system and path-folding reflector 4aa (4ba) to illuminate the first mask Ma (second mask Mb) in a superimposed manner. An aperture stop 5a (5b) for restricting the beams from the fly's eye lens 3a (3b) is located near the exit plane of the fly's eye lens 3a (3b). The aperture stop 5a (5b) has a function of varying the size and shape of a light intensity distribution near the exit plane of the fly's eye lens 3a (3b), i.e., on the illumination pupil (which will be referred to hereinafter as “pupil intensity distribution”). A configuration applicable herein as one for varying the size and shape of the pupil intensity distribution is, for example, one of those disclosed in Published U.S. Pat. Applications No. 2006/0055834, No. 2006/0171138, and No. 2006/0170901, and U.S. Pat. No. 5,530,518. The disclosures of the Published U.S. Pat. Applications No. 2006/0055834, No. 2006/0171138, and No. 2006/0170901, and U.S. Pat. No. 5,530,518 are incorporated herein by reference.
A beam transmitted by the first mask Ma and a beam transmitted by the second mask Mb travel, as shown in
In the present embodiment, as shown on the left side of
Namely, in a pattern region PAa of the first mask Ma, a pattern corresponding to the first illumination region IRa is illuminated in a polarization state set by the polarization state varying part in the first illumination system ILa and under an illumination condition defined by the size and shape of the pupil intensity distribution set by the aperture stop 5a. Furthermore, in a pattern region PAb of the second mask Mb located apart from the first mask Ma along the X-direction, a pattern corresponding to the second illumination region IR2 is illuminated in a polarization state set by the polarization state varying part in the second illumination system ILb and under an illumination condition defined by the size and shape of the pupil intensity distribution set by the aperture stop 5b. In this manner, the polarization state varying part and aperture stop 5a in the first illumination system ILa constitute a first setting part for setting the first illumination region IRa in the first illumination condition, and the polarization state varying part and aperture stop 5b in the second illumination system ILb constitute a second setting part for setting the second illumination region IRb in the second illumination condition. In addition, the polarization state varying parts and aperture stops 5a, 5b constitute an illumination condition varying part for varying the illumination conditions for illumination of the first illumination region IRa and the second illumination region IR2.
In this manner, as shown in
In the present embodiment, while the first mask Ma, the second mask Mb, and the wafer W are synchronously moved along the X-direction relative to the projection optical system PL, double scanning exposure of the pattern of the first mask Ma and the pattern of the second mask Mb is implemented in one shot area on the wafer W to form a synthetic pattern. The aforementioned double scanning exposure is repeated with two-dimensional step movement of the wafer W along the XY plane relative to the projection optical system PL, whereby synthetic patterns of the pattern of the first mask Ma and the pattern of the second mask Mb are sequentially formed in respective shot areas on the wafer W.
In the present embodiment, as described above, the rectangular illumination regions IRa and IRb elongated along the Y-direction are formed on the first mask Ma and on the second mask Mb located apart from each other along the X-direction, and the pattern image of the first illumination region IRa of the first mask Ma and the pattern image of the second illumination region IRb of the second mask Mb are formed in parallel along the X-direction on the wafer W. There are the two illumination systems ILa, ILb arranged in parallel and they have the optical axes AXa, AXb parallel to each other along the YZ plane parallel to the Y-direction (first direction), which is the longitudinal direction of the illumination regions IRa, IRb formed on the masks Ma, Mb, and perpendicular to the X-direction (second direction) and have the same configuration.
In this case, the effective reflection regions of the reflectors 4aa, 4ba for folding the optical path near the exit end of the illumination systems ILa, ILb tend to become larger, and this tends to lead to an increase in the size of the path-folding reflectors 4aa, 4ba; however, it becomes feasible to arrange the two illumination systems ILa, ILb in the compact form and in parallel with respect to the projection optical system PL and the masks Ma, Mb. As a result, the exposure apparatus of the present embodiment is able to form a synthetic pattern in one shot area on the wafer (photosensitive substrate) W by double printing of the two types of mask patterns therein, based on the relatively compact configuration.
In the above-described embodiment, the optical axes AXa, AXb of the two illumination systems ILa, ILb each are set along the plane (YZ plane) parallel to the longitudinal direction (Y-direction) of the rectangular illumination regions IRa, IRb formed on the first mask Ma and on the second mask Mb, and the first mask Ma and the second mask Mb are located apart from each other along the transverse direction (X-direction) of the illumination regions IRa, IRb. However, without having to be limited to this, it is also possible to adopt a modification example of such a layout, as shown in
In the modification example of the layout shown in
In the modification example of
In the aforementioned embodiment and the modification example of
In the modification example of
In the modification example of
In the foregoing embodiment and the modification example of
In the foregoing embodiment and the modification example of
In the foregoing embodiment and the modification example of
In the foregoing embodiment and the modification example of
The embodiment of
In each embodiment described above, the exit-side partial optical system of the first illumination system is the optical system (4a, 4aa) located downstream the fly's eye lens 3a as an optical integrator, or downstream the aperture stop 5a, and the exit-side partial optical system of the second illumination system is the optical system (4b, 4ab) located downstream the fly's eye lens 3b as an optical integrator, or downstream the aperture stop 5b. The exit-side partial optical systems of the first and second illumination systems are arranged in parallel and next to each other along the Y-direction perpendicular to the X-direction in which the first mask Ma and the second mask Mb are located apart from each other, and the optical axes (AXa, AXb) of the exit-side partial optical systems of the first and second illumination systems each are arranged along the plane (plane parallel to the YZ plane) parallel to the Y-direction perpendicular to the X-direction in which the first mask Ma and the second mask Mb are located apart from each other. By adopting this configuration, the first and second illumination systems can be intensively arranged in the compact form in spite of the double exposure apparatus configuration. Particularly, as the first illumination system and the second illumination system are arranged next to each other and in parallel, the configuration of the illumination systems in the double exposure apparatus can be made more compact.
The exposure apparatus of the foregoing embodiment can be used to manufacture micro devices (semiconductor devices, image pickup devices, liquid-crystal display devices, thin-film magnetic heads, etc.) by illuminating a mask (reticle) by the illumination optical apparatus (illumination step) and projecting a pattern to be transferred, formed in the mask, onto a photosensitive substrate through the projection optical system to effect exposure thereof (exposure step). An example of a technique of manufacturing semiconductor devices as micro devices by forming a predetermined circuit pattern in the wafer or the like as a photosensitive substrate by means of the exposure apparatus of the present embodiment will be described below with reference to the flowchart of
The first step 301 in
Subsequent steps include formation of circuit patterns in upper layers, and others, thereby manufacturing devices such as semiconductor devices. The above-described semiconductor device manufacturing method permits us to obtain semiconductor devices with extremely fine circuit patterns at high throughput. The steps 301 to 305 were arranged to perform the steps of depositing the metal on the wafer, applying the resist onto the metal film, and performing the exposure, development, and etching, but it is needless to mention that, prior to these steps, the method may include a process of first forming an oxide film of silicon on the wafer, then applying a resist onto the oxide film of silicon, and performing each of steps such as exposure, development, and etching.
The exposure apparatus of the present embodiment can also be used to manufacture a liquid-crystal display device as a micro device by forming predetermined patterns (circuit pattern, electrode pattern, etc.) on plates (glass substrates). An example of a technique in this case will be described below with reference to the flowchart of
The next color filter forming step 402 is to form a color filter in which a number of sets of three dots corresponding to R (Red), G (Green), and B (Blue) are arrayed in a matrix pattern, or in which sets of three stripe filters of R, G, and B are arrayed as a plurality of lines arranged in the horizontal scan line direction. After completion of the color filter forming step 402, a cell assembling step 403 is carried out. The cell assembling step 403 is to assemble a liquid crystal panel (liquid crystal cell), using the substrate with the predetermined pattern obtained in the pattern forming step 401, the color filter obtained in the color filter forming step 402, and so on.
In the cell assembly step 403, for example, a liquid crystal is poured into between the substrate with the predetermined pattern obtained in the pattern forming step 401 and the color filter obtained in the color filter forming step 402, to manufacture a liquid crystal panel (liquid crystal cell). The subsequent module assembly step 404 is to install each of components such as an electric circuit, a backlight, etc. for display operation of the assembled liquid crystal panel (liquid crystal cell) to complete the liquid-crystal display device. The above-described method of manufacturing the liquid-crystal display device permits us to obtain the liquid-crystal display device with an extremely fine circuit pattern at high throughput.
The above-described embodiment used the KrF excimer laser light source or the ArF excimer laser light source as the light source, but, without having to be limited to them, the present invention is also applicable to the exposure apparatus using any other appropriate light source, e.g., an F2 laser light source.
The invention is not limited to the foregoing embodiments but various changes and modifications of its components may be made without departing from the scope of the present invention. Also, the components disclosed in the embodiments may be assembled in any combination for embodying the present invention. For example, some of the components may be omitted from all components disclosed in the embodiments. Further, components in different embodiments may be appropriately combined.
| Number | Date | Country | Kind |
|---|---|---|---|
| P2006-112573 | Apr 2006 | JP | national |
This application is based upon and claims the benefit of priorities from Japanese Patent Application No. 2006-112573 filed on Apr. 14, 2006, and U.S. Provisional Application (the application number has not been assigned yet), filed on Jan. 29, 2007, the entire contents of which are incorporated herein by reference.
| Number | Date | Country | |
|---|---|---|---|
| 60897817 | Jan 2007 | US |
