JP2004072103A - Crystallization equipment, crystallization method, thin film transistor, and display device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide crystallization equipment capable of forming a crystallized semiconductor film of a large particle diameter by realizing sufficient lateral growth from a crystal nucleus. <P>SOLUTION: The crystallization equipment includes a phase shift mask and an illumination system for illuminating the phase shift mask. The phase shift mask includes a phase shifter by which the light from the illumination system is changed into the light having a light intensity distribution of an inverse peak pattern having the lowest light intensity in a corresponding area to the phase shifter. The crystallization equipment further includes an optical member for generating a light intensity distribution of a concave pattern having the light intensity lowest in the area corresponding to the phase shifter in the phase shift mask and increases toward a surrounding area thereof onto a predetermined plane; and an imaging optical system for setting an optically conjugate relation between the semiconductor film surface or the conjugation surface thereof and the predetermined surface. <P>COPYRIGHT: (C)2004,JPO

Description

The present invention relates to a crystallization apparatus and a crystallization method for irradiating an uncrystallized semiconductor film with energy light such as laser light to generate a crystallized semiconductor film. In particular, the present invention relates to a crystallization apparatus and a crystallization method for generating a crystallized semiconductor film by irradiating an uncrystallized semiconductor film with laser light whose phase has been modulated using a phase shift mask.

2. Description of the Related Art Conventionally, for example, a thin-film transistor (TFT) used for a switching element for controlling a voltage applied to a pixel of a liquid crystal display (LCD) is made of amorphous silicon (Amorphous). -Silicon, poly-silicon, and mono-silicon.

Polycrystalline silicon has higher electron or hole mobility than amorphous silicon. Therefore, when a transistor is formed using polycrystalline silicon, the switching speed is higher than that when amorphous silicon is used, so that the display response is faster and the design margin of other components can be reduced. is there. In the case where peripheral circuits such as a driver circuit and a DAC for converting a digital signal to an analog signal which are formed outside of the display body are formed in the display area, the use of polycrystalline silicon makes these peripheral circuits faster. Can work.

Polycrystalline silicon is made up of a collection of crystallized crystal grains, but has lower mobility of electrons or holes than single-crystal silicon. Further, in a small transistor formed using polycrystalline silicon, variation in the number of crystal grain boundaries in a channel portion poses a problem. Therefore, recently, in order to improve the mobility of electrons or holes and to reduce the variation in the number of crystal grain boundaries in the channel portion (active portion) of each TFT, a crystallization method for generating crystal grains having a larger grain size has been proposed. Many have been proposed.

Conventionally, as this kind of crystallization method, a phase control ELA (Excimer @ Laser @ Annealing) in which a polycrystalline semiconductor film or an amorphous semiconductor film is irradiated with an excimer laser beam through a phase shift mask to generate a crystallized semiconductor film. )"It has been known. The details of the phase control ELA are described in, for example, Masayoshi Matsumura “Surface Science” Vol. 21, No. 5, pp. 278-287, 2000 and JP-A-2000-306859 ([0030] to [0034], FIGS. 8 to 11).

In the phase control ELA, a light intensity distribution of a reverse peak pattern (a light intensity distribution in which the light intensity sharply increases as the distance from the position where the light intensity becomes minimum) is generated by a phase shift mask, and the light intensity of the reverse peak pattern is generated. An uncrystallized semiconductor film such as a polycrystalline semiconductor film or an amorphous semiconductor film is irradiated with a light beam having a periodic distribution. As a result, in the irradiated uncrystallized semiconductor film, a melting region is generated according to the light intensity distribution, and a crystal nucleus is formed in a portion that does not melt or a portion that solidifies first corresponding to a position where the light intensity is minimum. Then, the crystal grows laterally from the crystal nucleus toward the periphery (lateral growth), thereby generating large-sized crystal grains (single crystal).
JP-A-2000-306859 Matsumura Masayoshi "Surface Science" Vol. 21, No. 5, pp. 278-287, 2000

As described above, in the related art, the semiconductor film is irradiated with a light beam having a light intensity distribution of a reverse peak pattern, and a crystal nucleus is formed at a portion corresponding to a position where the light intensity is minimum in the light intensity distribution. Therefore, it is possible to control the position where crystal nuclei are formed.

However, it is impossible for the phase shift mask to control the light intensity distribution in an intermediate portion between two adjacent opposite peak portions.

Actually, in the prior art, the light intensity distribution in the middle portion generally has an irregular undulation (a wave-like distribution in which the light intensity repeatedly increases and decreases). In this case, in the crystallization process, the lateral growth started from the crystal nucleus toward the periphery is stopped at a portion where the light intensity decreases in the middle portion, and there is a disadvantage that the growth of a large crystal is hindered. Further, even if a substantially uniform light intensity distribution is obtained in the intermediate portion, lateral growth stops at an arbitrary position in the uniform light intensity distribution, and the disadvantage that the growth of a large crystal is hindered. is there.

The present invention has been made in view of the aforementioned problems, and a crystallization apparatus, a crystallization method, and a crystallization method capable of generating a crystallized semiconductor film having a large grain size by achieving sufficient lateral growth from a crystal nucleus. It is an object to provide a thin film transistor and a display device.

According to a first aspect of the present invention, there is provided an illumination system for illuminating a phase shift mask, wherein the light of an inverse peak pattern having the smallest light intensity in a region corresponding to a phase shift portion of the phase shift mask is provided. In a crystallization apparatus that irradiates a polycrystalline semiconductor film or an amorphous semiconductor film with light having an intensity distribution to generate a crystallized semiconductor film, a region corresponding to the phase shift unit based on light from the illumination system An optical member for forming a light intensity distribution of a concave pattern in which the light intensity is the smallest and the light intensity increases toward the periphery thereof on a predetermined surface, and the surface of the polycrystalline semiconductor film or the amorphous semiconductor film or A crystallization apparatus comprising a storage optical system for setting an optically conjugate relationship between the conjugate plane and the predetermined plane.

According to a preferred aspect of the first invention, the optical member is a transmission type amplitude modulation mask having a transmittance distribution according to a light intensity distribution of a concave pattern to be formed on the predetermined surface. It is preferable that the transmission type amplitude modulation mask has a light transmission portion having a constant thickness and a light absorption portion having a thickness distribution according to a light intensity distribution of a concave pattern to be formed on the predetermined surface. Further, it is preferable that the light absorbing portion has a sine-wave shaped surface as a whole. Further, it is preferable that the entire sinusoidal surface is formed in a continuous curved shape or a stepped shape.

According to a preferred aspect of the first invention, the optical member is an aperture-type amplitude modulation mask having an aperture ratio distribution according to a light intensity distribution of a concave pattern to be formed on the predetermined surface. It is preferable that the aperture type amplitude modulation mask has a large number of minute transmission regions or a large number of minute light shielding regions, or both. In addition, it is preferable that the size of the minute transmission region and the minute light shielding region is set to be substantially smaller than the resolution of the imaging optical system. Further, it is preferable that the imaging optical system is a reduction type optical system.

Further, according to a preferred aspect of the first invention, the optical member is provided on the predetermined surface so as to correspond to a region where a light beam is diverged and illuminated corresponding to the phase shift unit and a periphery of the phase shift unit. The light converging / diverging element generates a region where the light flux is converged and illuminated. It is preferable that the converging / diverging element has a diverging / refracting surface for diverging the light beam and a converging / refracting surface for condensing the light beam. Further, it is preferable that the divergent refraction surface and the converging refraction surface form a sinusoidal refraction surface as a whole. Further, it is preferable that the refraction surface having the overall sinusoidal shape is formed in a continuous curved shape or a step shape.

Further, according to a preferred aspect of the first invention, the optical member is a light intensity distribution forming element for forming a predetermined light intensity distribution having a larger light intensity at the periphery of the pupil plane of the illumination system or in the vicinity thereof than at the center. And a wavefront splitting element for wavefront splitting the light beam supplied from the illumination system into a plurality of light beams and condensing each of the wavefront split light beams on a region corresponding to the phase shift unit on the predetermined surface. ing. It is preferable that the wavefront splitting element has a plurality of optical elements having a light collecting function. Further, the predetermined light intensity distribution may have a circular central region having a relatively small light intensity and an annular peripheral region having a relatively large light intensity formed so as to surround the central region. preferable. Further, the predetermined light intensity distribution includes a central region having a relatively small light intensity elongated in a predetermined direction and a peripheral region having a relatively large light intensity formed to surround or sandwich the central region. It is preferred to have. Further, it is preferable that the light intensity distribution forming element includes a transmission filter having a predetermined light transmittance distribution disposed on or near the illumination pupil plane.

According to a preferred aspect of the first invention, a phase shift surface of the phase shift mask is formed on a surface opposite to the illumination system side. Further, the light intensity distribution applied to the polycrystalline semiconductor film or the amorphous semiconductor film includes a reverse peak pattern region where the light intensity is the smallest in a region corresponding to the phase shift portion of the phase shift mask, and the reverse peak pattern. It is preferable to have a concave pattern region in which light intensity increases from the pattern region toward the periphery, and to have an inflection point whose inclination decreases toward the periphery between the reverse peak pattern region and the concave pattern region.

According to a preferred aspect of the first invention, the polycrystalline semiconductor film or the amorphous semiconductor film and the phase shift mask are arranged substantially parallel to and close to each other. Alternatively, the apparatus further includes a second imaging optical system disposed in an optical path between the polycrystalline semiconductor film or the amorphous semiconductor film and the phase shift mask, wherein the polycrystalline semiconductor film or the amorphous semiconductor The surface of the film is set at a predetermined distance along the optical axis from a plane optically conjugate with the phase shift mask via the second imaging optical system. Alternatively, the apparatus further includes a second imaging optical system disposed in an optical path between the polycrystalline semiconductor film or the amorphous semiconductor film and the phase shift mask, wherein the polycrystalline semiconductor film or the amorphous semiconductor The surface of the film is set to a surface optically conjugate with the phase shift mask via the second imaging optical system, and the image-side numerical aperture of the second imaging optical system is a light having the reverse peak pattern. It is set to a required value for generating the intensity distribution.

According to the second aspect of the present invention, the phase shift mask is illuminated, and light having an inverse peak pattern light intensity distribution having the smallest light intensity in a region corresponding to the phase shift portion of the phase shift mask is irradiated with the polycrystalline semiconductor film or non-light. In the crystallization method of irradiating the crystalline semiconductor film to generate a crystallized semiconductor film, based on light from the illumination system, the light intensity is smallest in a region corresponding to the phase shift portion and toward the periphery thereof. A light intensity distribution of a concave pattern in which light intensity increases is formed on a predetermined surface, and the surface of the polycrystalline semiconductor film or the amorphous semiconductor film or a conjugate plane thereof and the predetermined surface are optically formed via an imaging optical system. The present invention provides a crystallization method characterized by setting a symmetrical relationship.

According to a preferred aspect of the second invention, the polycrystalline semiconductor film or the amorphous semiconductor film and the phase shift mask are arranged substantially parallel to and close to each other. Alternatively, a second imaging optical system is arranged in an optical path between the polycrystalline semiconductor film or the amorphous semiconductor film and the phase shift mask, and a surface of the polycrystalline semiconductor film or the amorphous semiconductor film is Is set at a predetermined distance from the plane optically conjugate with the phase shift mask along the optical axis of the second imaging optical system. Alternatively, a second imaging optical system is disposed in an optical path between the polycrystalline semiconductor film or the amorphous semiconductor film and the phase shift mask, and the image-side numerical aperture of the second imaging optical system is It is set to a required value for generating a light intensity distribution of a reverse peak pattern, and the polycrystalline semiconductor film or the amorphous is formed on a plane optically conjugate with the phase shift mask via the second imaging optical system. The surface of the high quality semiconductor film.

According to a third aspect of the present invention, there is provided a thin film transistor manufactured by the above-described crystallization method.

According to a fourth aspect of the present invention, there is provided a display device including the above-described thin film transistor.

According to the present invention, for example, the light intensity distribution of the two-step reverse peak pattern is formed on the semiconductor film of the substrate to be processed by the cooperation of the amplitude modulation mask or the phase modulation mask and the phase shift mask. Is realized, and a crystallized semiconductor film having a large grain size can be produced.

An embodiment of the present invention will be described with reference to the accompanying drawings.

FIG. 1 is a diagram schematically showing a configuration of a crystallization apparatus according to the first embodiment of the present invention. As shown in FIG. 1, the crystallization apparatus according to the first embodiment includes an illumination optical system 2 that illuminates a predetermined region of a substrate 6 to be processed, and a light source between the substrate 6 and the illumination optical system 2. , A phase shifter or phase shift mask 4 located on an optical path between the transmission type amplitude modulation mask 1 and the substrate 6 to be processed, and a transmission type amplitude modulation mask 1 A first imaging optical system 3 disposed on an optical path between the phase shift mask 4 and the second imaging optical system 5 disposed on an optical path between the phase shift mask 4 and the substrate 6 to be processed; And The illumination optical system 2 emits illumination light to the transmission type amplitude modulation mask 1.

The surface of the substrate 6 to be processed is positioned via the first imaging optical system 3 and the second imaging optical system 5 so as to have an optically conjugate relationship with the emission surface of the transmission type amplitude modulation mask 1. ing. The surface of the substrate 6 to be processed is shifted from the optically conjugate surface (the image surface of the second imaging optical system 5) to the phase shift surface 411 (the lower surface in FIG. 1) of the phase shift mask 4 from the optical axis. Along along. The first imaging optical system 3 and the second imaging optical system 5 may be any of a refraction type optical system, a reflection type optical system, and a refraction / reflection type optical system.

In the first embodiment, the substrate 6 to be processed is obtained, for example, by forming a base film and an amorphous silicon film on a glass plate for a liquid crystal display by a chemical vapor deposition method. The substrate 6 to be processed is held at a predetermined position on the substrate stage 7 by a vacuum chuck, an electrostatic chuck, or the like.

FIG. 2 is a diagram schematically showing an internal configuration of the illumination optical system 2 of FIG. As shown in FIG. 2, the illumination optical system 2 includes a light source 2a composed of a KrF excimer laser for supplying a light beam having a wavelength of, for example, 248 nm, a beam expander 2b for expanding the laser light beam from the light source 2a, The optical system includes first and second fly-eye lenses 2c and 2e in which a plurality of convex lenses are arranged on a plane, and first and second condenser optical systems 2d and 2f. Note that another appropriate light source such as a XeCl excimer laser light source can be used as the light source 2a.

(2) As schematically shown in FIG. 2, the light beam emitted from the light source 2a is expanded through the beam expander 2b and enters the first fly-eye lens 2c. Since the light beam incident on the first fly-eye lens 2c is condensed by each convex lens of the first fly-eye lens 2c, a plurality of points are substantially formed on the rear focal plane of the first fly-eye lens 2c. A light source is formed. Light beams from the plurality of point light sources illuminate the incident surface of the second fly-eye lens 2e in a superimposed manner via the first condenser optical system 2d.

The light beams incident on the second fly-eye lens 2e from the plurality of point light sources are respectively condensed by the convex lens of the second fly-eye lens 2e. More point light sources are formed than the rear focal plane of one fly-eye lens 2c. Light beams from a plurality of point light sources formed on the rear focal plane of the second fly-eye lens 2e further enter the second condenser optical system 2f.

The first fly-eye lens 2c and the first condenser optical system 2d constitute a first homogenizer, and make the incident angle on the transmission type amplitude modulation mask 1 uniform. Similarly, the second fly-eye lens 2e and the second condenser optical system 2f constitute a second homogenizer, and make the in-plane position on the transmission type amplitude modulation mask 1 uniform. Therefore, a light beam having a substantially uniform light intensity distribution is emitted from the illumination optical system 2 in a superimposed manner. Thus, the illumination optical system 2 emits a light beam having a uniform light intensity distribution. This light beam illuminates the incident surface of the transmission type amplitude modulation mask 1.

FIG. 3 is a diagram illustrating the configuration and operation of the transmission type amplitude modulation mask 1 according to the first embodiment. FIG. 4 is a diagram showing a manufacturing process of the transmission type amplitude modulation mask 1 according to the first embodiment. FIGS. 3 and 4 show only the basic unit portion of the transmission type amplitude modulation mask 1 for clarity of the drawings, but the transmission type amplitude modulation mask 1 actually has the basic unit portion of the transmittance distribution. They are arranged one-dimensionally along the direction (x direction).

As shown in FIG. 3A, the transmission type amplitude modulation mask 1 has a parallel plate-shaped light transmission portion 1a having a constant thickness, and a light absorption portion having a thickness which changes to a sine wave shape as a whole. 1b, and the light transmitting portion 1a and the light absorbing portion 1b are formed integrally, for example. The light absorbing material (light shielding material) forming the light absorbing portion 1b is, for example, a material used for a halftone type phase shift mask, that is, MoSi, MoSiON, ZrSiO, a-Carbon, SiN / TiN, TiSiN, Cr, or the like. It is. The transmission type amplitude modulation mask 1 modulates the light intensity of the laser light beam having a uniform light intensity distribution from the illumination optical system 2 as shown in FIG.

Next, an example of a manufacturing process of the transmission type amplitude modulation mask 1 will be described with reference to FIG. First, as shown in FIG. 4A, a light absorbing film 1e, for example, ZrSiO is uniformly formed on a light transmitting portion 1a made of quartz glass, and then a resist 1f is applied to the surface of the light absorbing film 1e. . Next, electron beam drawing and development processing are performed while continuously changing the dose amount to form a resist film 1g having a continuous sinusoidal curved surface shape as shown in FIG. 4B. Next, by using the resist film 1g as a mask, the light absorbing film 1e is etched by using a dry etching technique to form a light absorbing portion 1b having a continuous curved surface as shown in FIG. The transmission type amplitude modulation mask 1 as shown is formed. In the manufacturing process of the mask 1, for example, by forming and patterning the light absorbing film 1e a plurality of times, a light absorbing portion 1b having a step-shaped surface (eg, a surface approximated by an 8-level step) is provided. The transmission type amplitude modulation mask 1 may be formed. The transmission type amplitude modulation mask emits transmitted light having a sinusoidal light intensity distribution.

FIG. 5A is a view schematically showing a configuration example of a basic unit portion of the phase shift mask 4. As shown in FIG. 5A, the basic unit portion of the phase shift mask 4 has, for example, a phase shift surface including four rectangular first to fourth regions 4 a to 4 d having different thicknesses, respectively. The first region 4a and the third region 4c and the second region 4b and the fourth region 4d are provided diagonally, respectively. The two diagonally located rectangular regions 4a-4c and 4b-4d provide a phase difference of π between the transmitted light beams, for example. That is, the phase shift mask 4 has a step-like shape in which the first to fourth regions 4a to 4d are sequentially thicker. The steps in each of the regions 4a to 4d may be formed by etching or by deposition.

As a specific example, for example, when the phase shift mask 4 is formed of quartz glass having a refractive index of 1.5 with respect to a light beam having a wavelength of 248 nm, the distance between the first region 4a and the second region 4b Has a step of 124 nm, a step of 248 nm is provided between the first region 4a and the third region 4c, and a step of 372 nm is provided between the first region 4a and the fourth region 4d. ing. The vicinity of the intersection of the four phase shift lines, which are the boundaries between the regions 4a to 4d, is a phase shift unit 4e. The center 1 d of the convex portion below the light absorbing portion 1 b in the transmission type amplitude modulation mask 1 is positioned so as to correspond to the phase shift portion 4 e of the phase shift mask 4.

In FIG. 5A, the phase shift surface which is the surface having the phase shift portion 4e is shown as being formed on the upper surface of the phase shift mask 4 for clarity of the drawing. The phase shift surface 4 is formed on the surface on the side of the second imaging optical system 5 (the side opposite to the illumination optical system 2 side, that is, the lower side in FIG. 1 on the emission side).

FIG. 5B is a top view showing another example of the phase shift mask 4 in which four basic unit portions of FIG. 5A are arranged on a plane. The phase shift mask 4 shown in FIG. 5B is configured by arranging a plurality of basic unit portions two-dimensionally, that is, in a 2 × 2 matrix.

The phase shift mask 4 according to the first embodiment has four regions 4a to 4d having different thicknesses. For example, as shown in FIG. 5C, two different thicknesses that give a phase difference of π to a transmitted light beam are provided. May be provided. When the phase shift mask 4 has two regions, these two regions are alternately and one-dimensionally arranged along one axis, and the phase shift portion is located at the boundary between the two types of regions. I have.

Note that the phase shift mask is not limited to the described one, and a two-dimensional pattern can also be used.

(4) The light beam emitted from the illumination optical system 2 and having a substantially uniform light intensity distribution passes through the transmission type amplitude modulation mask 1 and undergoes the amplitude modulation of the light intensity. As shown in FIG. 3, the light beam emitted from the emission surface 1c of the transmission type amplitude modulation mask 1 has the lowest light intensity at a position corresponding to the center of the convex portion of the light absorbing portion 1b, and the light intensity decreases as the distance from the center increases. The light intensity distribution is such that the light intensity is highest and the light intensity is highest at a position corresponding to the center of the concave portion of the light absorbing portion 1b, that is, the light intensity distribution has a concave pattern on the upper side. It is preferable that the transmission type amplitude modulation mask 1 is set so that the width dimension of the light intensity distribution of the concave pattern on the upper side is equal to the width of the liquid crystal pixel.

(4) The light beam having been subjected to light intensity modulation emitted from the transmission type amplitude modulation mask 1 illuminates the phase shift mask 4 via the first imaging optical system 3. The light beam transmitted through the phase shift mask 4 is applied to the processing target substrate 6 via the second imaging optical system 5.

FIG. 6 is a partially enlarged cross-sectional view for explaining the basic operation of the phase shift mask 4 in the first embodiment. Hereinafter, the basic operation of the phase shift mask 4 when the transmission type amplitude modulation mask 1 is not interposed on the optical path between the illumination optical system 2 and the phase shift mask 4, that is, when a substantially uniform light beam is incident will be described. I do.

In the phase shift mask 4, since the phase difference between two adjacent regions is set to π / 2, the light intensity decreases at the position corresponding to the phase shift line 412 but does not become zero. On the other hand, since the integral value of the complex transmittance in the circular area centered on the intersection of the phase shift line 412 is set to be 0, the light intensity is almost 0 at this intersection, that is, at the position corresponding to the phase shift unit 4e. become.

Accordingly, the light intensity distribution of the light beam transmitted through the phase shift mask 4 having a plurality of basic unit portions corresponds to each phase shift portion 4e of the phase shift mask 4 on the processing target substrate 6, as shown in FIG. At this point, the light intensity has a minimum peak value, for example, approximately 0, and has a light intensity distribution of a reverse peak pattern in which the light intensity sharply increases as the distance from the phase shift unit 4e increases. That is, the position where the light intensity distribution of the periodic reverse peak pattern becomes minimum is determined by the phase shift unit 4e. Note that the light intensity distribution of the periodic reverse peak pattern has substantially the same profile in both the xz plane and the yz plane. Further, the width dimension of the light intensity distribution of the reverse peak pattern changes in proportion to the square of the distance between the phase shift mask 4 and the substrate 6 (that is, the defocus amount).

As described above, when the semiconductor film is irradiated with a light beam having only the light intensity distribution of the inverse peak pattern as shown in FIG. 6, the crystal nucleus is located at the intermediate portion between the inverse peak patterns. Lateral growth that started toward is stopped. The crystallization apparatus according to the first embodiment includes a transmission type amplitude modulation mask 1 on an optical path between the illumination optical system 2 and the phase shift mask 4 in order to realize sufficient lateral growth from a crystal nucleus. And a first imaging optical system 3.

FIGS. 7A and 7B are diagrams showing light intensity distributions of light beams transmitted through the transmission type amplitude modulation mask 1 and the phase shift mask 4 obtained on the substrate 6 to be processed. In the first embodiment, as described above, the transmission type amplitude modulation mask 1 amplitude-modulates a light beam having a uniform light intensity distribution, and forms an upwardly concave light pattern as shown in FIG. It has a function of converting into a light beam having an intensity distribution periodically. On the other hand, the phase shift mask 4 has a function of converting a light beam having a uniform light intensity distribution into a light beam having a light intensity distribution of a reverse peak pattern as shown in FIG. 6 periodically.

Since the crystallization apparatus according to the first embodiment has the transmission type amplitude modulation mask 1 and the phase shift mask 4, the light beam that has reached the substrate 6 to be processed receives the transmission type amplitude modulation mask 1 and the phase shift mask. 4 and both are affected. Therefore, the light beam irradiated on the semiconductor film of the substrate 6 to be processed is represented by the product of the light intensity distribution of the inverse peak pattern distributed at the same period and the light intensity distribution of the concave pattern above in FIG. 7A. The light intensity distribution of a two-stage reverse peak pattern as shown in FIG. In the light intensity distribution of the periodic two-stage inverted peak pattern, the light intensity is almost 0 at a point corresponding to the phase shift unit 4e and is away from this point so as to correspond to the light intensity distribution of the inverted peak pattern described above. , The light intensity increases radially and reaches a predetermined value. That is, the position where the light intensity distribution of the periodic two-stage reverse peak pattern becomes the minimum is determined by the position of the phase shift unit 4e.

In the first embodiment, the light intensity distribution of the periodic two-step reverse peak pattern is the above-described light intensity distribution of the concave pattern and the periodic light intensity distribution of the yz direction. Corresponding to the light intensity distribution of the concave pattern, as shown in FIG. 8, the intermediate portion between adjacent reverse peak pattern portions is uniform in the y direction and almost monotonous only along the x direction. Has increased. In addition, the light intensity distribution of the two-step reverse peak pattern has an inflection point at which the slope decreases between the reverse peak pattern portion and the concave pattern portion above.

When the light beam having the light intensity distribution of the two-step reverse peak pattern is applied to the substrate 6 to be processed, the light intensity is minimized, that is, almost zero (the point corresponding to the phase shift part 4e). Crystal nuclei are formed in the portions. More specifically, a crystal nucleus is generated at a position with a large inclination in the light intensity distribution of the reverse peak pattern. Polycrystal is generated at the center of the reverse peak pattern portion, and then the crystal outside the nucleus grows as a crystal. The position where the crystal grows is generally a position with a large inclination.

Next, lateral growth is started from the crystal nucleus along the x direction where the light intensity gradient (that is, the temperature gradient) is large. In the light intensity distribution of the two-step reverse peak pattern, since there is substantially no portion where the light intensity decreases in the middle part, the lateral growth reaches the peak from the crystal nucleus without stopping halfway, realizing a large crystal growth can do. In particular, in the first embodiment, since there is an inflection point where the inclination decreases between the inverse peak pattern portion and the concave pattern portion above, the light beam having the light intensity distribution of the two-stage inverse peak pattern is processed. When the semiconductor film of the substrate 6 is irradiated, it is crystallized in a wide area extending from the center to the width of the light intensity distribution of the two-step reverse peak pattern. In addition, a single crystal can be grown for each pixel by setting the width of the light intensity distribution of the two-step reverse peak pattern equal to the pixel pitch of the liquid crystal, for example. That is, a switching transistor including a thin film transistor can be formed in a single crystal or a region formed in each pixel.

As described above, in the first embodiment, sufficient lateral growth from crystal nuclei can be realized, and a crystallized semiconductor film having a large grain size can be generated. Since the crystal generated by the crystallization apparatus according to the first embodiment has a large grain size, the crystal has high electron or hole mobility in the lateral growth direction (x direction). Therefore, by arranging the source and drain of the transistor in the direction of lateral growth, a transistor with excellent characteristics can be manufactured.

In the first embodiment, the second imaging optical system 5 located between the phase shift mask 4 and the processing target substrate 6 requires very high resolution and imaging performance. The first imaging optical system 3 located between the mold amplitude modulation mask 1 and the phase shift mask 4 does not require so high resolution and imaging performance. In other words, the light beam formed on the surface of the processing target substrate 6 by the action of the transmission type amplitude modulation mask 1 and having the light intensity distribution of the concave pattern is formed by the first imaging optical system 3 and the second imaging optical system. The light beam having a light intensity distribution of an inverse peak pattern formed on the surface of the substrate 6 to be processed by the action of the phase shift mask 4 is not so sensitive to the resolution of the second imaging optical system 5. Is very sensitive to the resolution.

Therefore, in the first embodiment, it is preferable that the phase shift surface of the phase shift mask 4 is formed on the second imaging optical system 5 side. In such a configuration, since the first imaging optical system 3 includes the glass substrate portion of the phase shift mask 4, the imaging performance is likely to be reduced due to the aberration, but the second imaging Since the optical system 5 does not include the glass substrate portion of the phase shift mask 4, high resolution and high imaging performance can be secured without being affected by the aberration.

FIG. 9 is a diagram schematically showing a crystallization apparatus according to a first modification of the first embodiment. The first modification of the first embodiment has a configuration similar to that of the first embodiment. However, a crystallization apparatus according to the first modification is different from the first embodiment in that an aperture-type amplitude modulation mask is used instead of the transmission-type amplitude modulation mask 1. 11 is basically different from the first embodiment. FIG. 10 is a top view of the aperture type amplitude modulation mask 11 and a diagram for explaining the operation of the aperture type amplitude modulation mask 11. Hereinafter, the first modified example will be described focusing on the difference from the first embodiment. In FIG. 9, the illustration of the internal configuration of the illumination optical system 2 is omitted for clarity of the drawing.

The aperture type amplitude modulation mask 11 according to the first modification of the first embodiment is formed of a light transmitting member having a constant thickness, and the surface of the light transmitting member (for example, the first imaging optical system 3). As shown in FIG. 10, a large number of minute transmission areas and a large number of minute light-shielding areas are distributed in a pattern in which the central part is shielded and the transmittance increases toward both ends, as shown in FIG. ing. Specifically, the aperture-type amplitude modulation mask 11 is formed by, for example, spattering a minute light-shielding region made of chrome having a square shape with a side length of s on a quartz glass substrate and then patterning it.

Although FIG. 10 shows only the basic unit of the aperture-type amplitude modulation mask 11 for clarity of the drawing, the aperture-type amplitude modulation mask 11 actually has the basic unit in the direction of the aperture ratio distribution. It has a one-dimensionally repeated arrangement along (x direction). Further, in FIG. 10, the pattern of the aperture ratio distribution is configured as a combination of square elements of a fixed size, but is not limited to this. For example, an arbitrary pattern such as a combination of rectangles whose length and width change may be used. Further, the aperture type amplitude modulation mask 11 does not have a light transmitting member, and may be, for example, only a metal plate provided with an opening.

The distribution of the minute transmission region and the minute light shielding region in the basic unit portion of the aperture type amplitude modulation mask 11, that is, the pattern forming the aperture ratio distribution has the smallest aperture ratio at the center of the basic unit portion and is separated from the center of the basic unit portion. Is set so that the aperture ratio increases in accordance with the following equation. Further, the portion having the smallest aperture ratio distribution in the basic unit portion of the aperture type amplitude modulation mask 11 is positioned so as to correspond to the phase shift portion 4e in the basic unit portion of the phase shift mask 4. Therefore, the aperture type amplitude modulation mask 11 amplitude-modulates a light beam having a substantially uniform light intensity distribution, and has the lowest light intensity in a region corresponding to the phase shift unit 4e, and the light intensity decreases as the distance from this region increases. It has a function of converting the light beam into a light beam having a light intensity distribution of a concave pattern in addition to the height.

In the first modification, the exit surface of the aperture type amplitude modulation mask 11 (the surface on which the light beam has the light intensity distribution of the concave pattern on the top) is formed by the first imaging optical system 3 and the second imaging optical system 5. Are arranged so as to be optically conjugated with the surface of the substrate 6 to be processed. Therefore, in a state where the phase shift mask 4 is not interposed, the light beam irradiated on the surface of the processing target substrate 6 is applied to the region corresponding to the phase shift portion 4e as in the case of the emission surface of the aperture type amplitude modulation mask 11. The light intensity is the lowest, the light intensity increases as the distance from the region increases, and the light intensity distribution has a concave pattern.

The light intensity distribution of the concave pattern above has a substantially curved profile as shown in FIG. 10 in the xz plane, but the profile in the yz plane is uniform. Further, it is preferable that the width dimension of the light intensity distribution of the upper concave pattern is set to be equal to the pixel pitch of the liquid crystal.

Since the crystallization apparatus according to the first modification includes the aperture type amplitude modulation mask 11 and the phase shift mask 4, the light beam reaching the substrate 6 to be processed emits the aperture type amplitude modulation mask 11 and the phase shift mask 4. And both are affected. Therefore, similarly to the first embodiment, the light beam irradiated on the semiconductor film of the substrate 6 to be processed has the light intensity distribution of the reverse peak pattern distributed at the same period and the light intensity distribution of the concave pattern above. The light intensity distribution of a two-stage reverse peak pattern as shown in FIG. In the light intensity distribution of the periodic two-stage reverse peak pattern, the light intensity is almost 0 in the region corresponding to the phase shift unit 4e and corresponds to the light intensity distribution of the reverse peak pattern described above. , The light intensity suddenly increases radially and reaches a predetermined value. That is, the position where the light intensity distribution of the periodic two-stage reverse peak pattern becomes the minimum is determined by the position of the phase shift unit 4e.

In the first modified example, similarly to the first embodiment, the light beam having the light intensity distribution of the two-step reverse peak pattern is formed by the action of both the aperture type amplitude modulation mask 11 and the phase shift mask 4. Is irradiated on the semiconductor film, the lateral growth reaches a peak from the crystal nucleus without stopping halfway, and a crystallized semiconductor film having a large grain size can be generated.

In the first modified example, the aperture ratio distribution of the aperture-type amplitude modulation mask 11 changes not discretely but discretely (in a stepwise manner). When the light is irradiated onto the semiconductor film of the substrate 6 to be processed, minute unevenness is likely to occur in the light intensity distribution of the concave pattern on the light beam. However, even if fine unevenness occurs in the light intensity distribution of the concave pattern on the top, when the light intensity distribution is converted into a temperature distribution, the fine unevenness of the light intensity distribution is averaged, and the fine unevenness of the temperature distribution is obtained. , The influence of minute unevenness can be neglected.

The following conditions are set so that the resolution of the first imaging optical system 3 becomes larger (lower) than the unit size s of the aperture in order to substantially suppress the occurrence of minute unevenness in the light intensity distribution of the concave pattern on the upper side. It is preferable to satisfy the expression (1).

s <1.22 × λ / NA1 (1)
Here, λ is the center wavelength of the light beam emitted from the illumination optical system 2, and NA 1 is the numerical aperture on the emission side of the first imaging optical system 3. That is, the value on the right side of the inequality sign in the conditional expression (1) indicates the resolution R1 of the first imaging optical system 3.

Therefore, in the first modification, even if the aperture ratio distribution in the aperture type amplitude modulation mask 11 changes discretely (stepwise), the resolution of the first imaging optical system 3 is set to a certain low level. As shown in FIG. 10, it is possible to irradiate the semiconductor film of the substrate 6 with a light beam that changes smoothly and has a light intensity distribution of a concave pattern. Alternatively, in order to substantially suppress the occurrence of minute unevenness in the light intensity distribution of the concave pattern formed on the semiconductor film of the substrate 6 to be processed, the first imaging optical system 3 intentionally has an appropriate aberration. May be given. When chromium is easily deteriorated by the laser light applied to the aperture type amplitude modulation mask 11, the illuminance of the applied laser light can be improved by configuring the first imaging optical system 3 as a reduction type optical system. Is preferably reduced relatively.

FIG. 11 is a diagram schematically showing a crystallization apparatus according to a second modification of the first embodiment. The second modification of the first embodiment has a configuration similar to that of the first embodiment, but the crystallization apparatus according to the second modification is a phase modulation mask instead of the transmission type amplitude modulation mask 1. This is basically different from the first embodiment in that a light converging / diverging element 12 is provided. FIG. 12 is a side view showing the light converging / diverging element 12 and a diagram for explaining the operation of the light converging / diverging element 12. Hereinafter, the second modified example will be described focusing on the difference from the first embodiment. In FIG. 11, the illustration of the internal configuration of the illumination optical system 2 is omitted for the sake of clarity.

As shown in FIG. 12, the basic unit portion of the light converging / diverging element 12 has two convex portions protruding toward the light beam emission side and a concave portion sandwiched between these convex portions. Means that the refracting surface 12a has a substantially sinusoidal shape as a whole. The two convex portions are converging / refracting surfaces 12c for converging the light beam incident on the converging / diverging element 12, and the concave portions are diverging / refracting surfaces 12b for diverging the light beam. With the converging / refracting surface 12c and the diverging / refracting surface 12b, the basic unit portion of the converging / diverging element 12 has a one-dimensional refracting function along the x direction.

Of the sinusoidal refraction surfaces 12a of the converging / diverging element 12, the center of the diverging / refracting surface 12b corresponds to the phase shift portion 4e of the basic unit portion of the phase shift mask 4, and the center of the converging / refracting surface 12c. The converging / diverging element 12 and the phase shift mask 4 are positioned such that the portion (ie, the most protruding center line) corresponds to each center line of the first to fourth regions parallel to the y direction. I have.

Although FIG. 12 shows only the basic unit of the converging / diverging element 12 for clarity of the drawing, the converging / diverging element 12 actually has a direction in which the basic unit has a refraction function (x direction). ) Along the one-dimensionally repeated form.

Of the light beams having a uniform light intensity distribution incident on the basic unit portion of the converging / diverging element 12, the light beam transmitted through the diverging / refracting surface 12b undergoes diverging action, and the light transmitted through the converging / refracting surface 12c. The beam is subjected to a light condensing action, and reaches a predetermined surface 12 d slightly spaced from the exit surface of the light converging / diverging element 12 toward the first imaging optical system 3. As shown in FIG. 12, the light beam transmitted through the condensing and diverging element 12 has the lowest light intensity at each phase shift section 4e and increases with distance from the phase shift section 4e, as shown in FIG. Has a light intensity distribution of a concave pattern periodically. Specifically, the light intensity distribution of the concave pattern on the upper side has the lowest light intensity at the position corresponding to the center of the divergent refraction surface 12b, and has the highest light intensity at the position corresponding to the center of the converging / refraction surface 12c.

The light intensity distribution of the concave pattern above has a curved profile as shown in FIG. 12 in the xz plane, but the profile in the yz plane is uniform. Further, it is preferable that the width dimension of the light intensity distribution of the upper concave pattern is set to be equal to the pixel pitch of the liquid crystal.

In the second modified example, the refraction surface of the light-converging / diverging element 12 has a one-dimensional refraction function, but is not limited thereto, and has a two-dimensional refraction function along two orthogonal directions. It may be. In this case, the light intensity distribution of the concave pattern formed on the substrate 6 to be processed by the operation of the light converging / diverging element 12 has the same profile of the concave pattern on two orthogonal planes.

The predetermined surface 12 d is disposed so as to be optically conjugate with the surface of the substrate 6 via the first imaging optical system 3 and the second imaging optical system 5. Therefore, when the phase shift mask 4 is not interposed, the light beam having a uniform light intensity distribution from the illumination optical system 2 is converted by the condensing and diverging element 12 which is a phase modulation mask, and the light intensity of the concave pattern The surface of the processing target substrate 6 is irradiated with a light beam having a distribution.

Since the crystallization apparatus according to the second modification includes the converging / diverging element 12 and the phase shift mask 4, the light beam reaching the substrate 6 to be processed is It has both effects. Therefore, the light beam irradiated on the semiconductor film of the substrate 6 to be processed is represented by the product of the light intensity distribution of the inverse peak pattern distributed at the same period and the light intensity distribution of the concave pattern above in FIG. 7A. The light intensity distribution of a two-stage reverse peak pattern as shown in FIG. In the light intensity distribution of the periodic two-stage inverted peak pattern, the light intensity is almost 0 at a point corresponding to the phase shift unit 4e and is away from this point so as to correspond to the light intensity distribution of the inverted peak pattern described above. Accordingly, the light intensity suddenly increases in a parabolic manner and reaches a predetermined value. That is, the position where the light intensity distribution of the periodic two-stage reverse peak pattern becomes the minimum is determined by the position of the phase shift unit 4e.

In the second modified example as well, as in the first embodiment, the light beam having the light intensity distribution of the two-step reverse peak pattern is generated on the substrate 6 by the action of both the condensing and diverging element 12 and the phase shift mask 4. Since irradiation is performed on the semiconductor film, lateral growth reaches a peak from the crystal nucleus without stopping halfway, and a crystallized semiconductor film having a large grain size can be generated.

In order to manufacture the light converging / diverging element 12, for example, a resist is applied to the surface of a quartz glass substrate, and electron beam writing and development are performed while continuously changing the dose, so that a resist film having a continuous curved surface shape is formed. Generate Thereafter, the condensing / diverging element 12 having a continuous curved refraction surface is formed by using a dry etching technique. In the above-described manufacturing process, for example, the condensing and diverging element 12 having the step-shaped refraction surface may be formed by repeating the formation and patterning of the resist film a plurality of times.

FIG. 13A is a diagram showing the light converging / diverging element 12 having a step-shaped refraction surface. FIG. 13B is a diagram showing a simulation result regarding the light intensity distribution of the concave pattern on the light beam obtained on the phase shift mask 4. As shown in FIG. 13A and FIG. 13B, when the converging / diverging element 12 has a step-shaped refracting surface (for example, a refracting surface approximated by an 8-level step), the light converging / diverging element 12 has a predetermined surface 12 d on the emission side. The light intensity distribution of the light beam does not change smoothly. However, in the second modification, by setting the resolution of the first imaging optical system 3 to a certain low level, even if the refraction surface of the converging / diverging element 12 is approximated by a step, the refraction surface smoothly changes as shown in FIG. 13C. In addition, a light beam having a light intensity distribution of a concave pattern can be irradiated onto the semiconductor film of the substrate 6 to be processed.

The light converging / diverging element 12 is not limited to a continuous curved surface or a multi-stage approximation thereof, and may be configured as a “kinoform” in which a range of 0 to 2π is turned back as a phase difference. Further, the converging / diverging function may be realized by the refractive index distribution of the optical material without providing the converging / diverging element 12 with a refractive surface. In this case, a conventional technique such as a photopolymer whose refractive index is modulated by light intensity or ion exchange of glass can be used. Moreover, a hologram or a diffractive optical element may be used to realize a light conversion action equivalent to that of the converging / diverging element 12.

FIG. 14 is a diagram schematically showing a crystallization apparatus according to a third modification of the first embodiment. FIG. 15 is a diagram schematically showing the illumination optical system 2 of FIG. The third modification of the first embodiment has a configuration similar to that of the first embodiment, but the crystallization apparatus according to the third modification uses a microlens array 13 instead of the transmission type amplitude modulation mask 1. The first embodiment is basically different from the first embodiment in that a transmission filter 14 which is a light intensity distribution forming element is provided on the illumination pupil plane of the illumination optical system 2 or in the vicinity thereof. Hereinafter, the third modified example will be described focusing on the difference from the first embodiment.

で は As shown in FIG. 14, in the third modification, the microlens array 13 is arranged at the position of the transmission type amplitude modulation mask 1 in the first embodiment. Further, as shown in FIG. 15, in the illumination optical system 2, a transmission filter 14 is disposed on the rear focal plane of the second fly-eye lens 2e (that is, the illumination pupil plane) or in the vicinity thereof.

FIG. 16 is a diagram schematically showing a configuration of the transmission filter 14 arranged at or near the illumination pupil plane. The transmission filter 14 has, for example, a circular central region 14a having a transmittance of 50%, and an annular peripheral region 14b formed so as to surround the central region 14a and having a transmittance of approximately 100%. That is, in or near the illumination pupil plane, the light intensity of the light beam transmitted through the central region 14a is relatively low, and the light intensity of the light beam transmitted through the peripheral region 14b is relatively high. Therefore, the illumination optical system 2 emits a light beam that is uniform but has a lower light intensity distribution at the center than at the periphery.

The center region 14a of the transmission filter 14 is formed by, for example, forming a chromium film (or a ZrSiO film or the like) having a thickness corresponding to the transmittance by a sputtering method and then patterning the film by etching or the like. In the case of this configuration, chrome as a light shielding material reflects some light and absorbs some light.

The central region 14a of the transmission filter 14 is obtained by, for example, forming a chromium film (or a ZrSiO film or the like) having a thickness corresponding to the transmittance by a sputtering method and then patterning the film by etching or the like. Chromium as a light shielding material reflects some light and absorbs some light. The central region 14a can also be obtained by forming and patterning a multilayer film designed to partially reflect light of the used wavelength.

(4) When a multilayer film is used as a reflective material, there is an advantage that heat is not generated due to absorption of unnecessary light, but it is necessary to consider that reflected light does not become stray light and cause flare. In addition, it is necessary to adjust the type and thickness of the light shielding material and the reflective material so that a phase difference does not substantially occur between the central region 14a and the peripheral region 14b. In the third modification, the central region 14a has a circular shape, but may have another shape such as a triangle or a rectangle.

FIG. 17 is a diagram schematically showing a basic unit portion of the microlens array 13. Referring to FIG. 17, a microlens element (optical element) 13a, which is a basic unit portion of the microlens array 13, has a refraction surface 13b such as a spherical surface that protrudes toward the first imaging optical system 3 and has a secondary curved surface. Have. Due to the refraction surface 13b, the micro lens element 13a of the micro lens array 13 has a two-dimensional light collecting function along the x direction and the y direction. The center of the refraction surface 13b of each microlens element 13a is positioned so as to correspond to the phase shift portion 4e of the basic unit of the phase shift mask 4. 17 shows only the basic unit portion of the microlens array 13 for clarity of the drawing, but the microlens elements 13a of the microlens array 13 are two-dimensionally (vertically and horizontally and densely). Are located.

The light beam incident on the microlens element 13a of the microlens array 13 is condensed through the refraction surface 13b, and is spotted on the focal plane of the microlens element 13a (that is, the rear focal plane of the microlens array 13). A light beam is formed. As described above, the microlens array 13 is arranged on the optical path between the illumination optical system 2 and the phase shift mask 4, and splits the light beam incident from the illumination optical system 2 into a plurality of light beams, A wavefront splitting element for condensing each split light beam to the corresponding phase shift unit 4e or its vicinity is configured. In the third modification, the rear focal plane 13 c of the microlens array 13 is optically conjugate with the surface of the substrate 6 via the first imaging optical system 3 and the second imaging optical system 5. They are arranged in a relationship.

FIG. 18 is a diagram illustrating the light intensity distribution of the light beam on the rear focal plane 13c by the action of both the transmission filter 14 and the microlens array 13. As shown in FIG. 18, the light beam transmitted through the microlens array 13 via the transmission filter has a small number of light beams incident vertically and a relatively large number of light beams incident obliquely. Therefore, on the rear focal plane 13c, the light beam has the smallest light intensity at each phase shift portion 4e, the light intensity increases as the distance from the phase shift portion 4e increases, and the light beam has a concave pattern light intensity distribution. Specifically, the light intensity distribution of the concave pattern on the upper side has the lowest light intensity at a position corresponding to the center of the refraction surface 13b and the highest light intensity at positions corresponding to both ends of the refraction surface 13b.

Note that the light intensity distribution of the concave pattern above has a similar profile in both the xz plane and the yz plane. Further, it is preferable that the width dimension of the light intensity distribution of the upper concave pattern is set to be equal to the pixel pitch of the liquid crystal.

FIG. 19 is a diagram showing a light intensity distribution obtained on the substrate to be processed by the cooperation of the transmission filter 14, the microlens array 13, and the phase shift mask 4. As described above, the transmission filter 14 converts a light beam having a uniform light intensity distribution into a light beam having the light intensity which is the smallest at the center, increases with distance from the center, and has a light intensity distribution of a concave pattern. It has the function of converting to a beam. The microlens array 13 has a function of converting an incident light beam into a spot-like light beam that is applied only to a predetermined area. Further, the phase shift mask 4 has a function of converting a light beam having a uniform light intensity distribution into a light having a light intensity distribution having a reverse peak pattern as shown in FIG. 7B. Have.

{Circle around (2)} As described above, the rear focal plane 13c of the microlens array 13 as the phase modulation mask and the surface of the processing target substrate 6 are arranged so as to have an optically conjugate relationship. Therefore, in a state where the phase shift mask 4 is not interposed, when a light beam having a uniform light intensity distribution passes through the microlens array 13, the light having a light intensity distribution of a concave pattern is formed on the surface of the substrate 6 to be processed. The beam is irradiated.

(4) Since the crystallization apparatus according to the third modification includes the transmission filter 14, the microlens array 13, and the phase shift mask 4, the light beam reaching the substrate 6 to be processed is subjected to three actions of these members. Therefore, the light beam reaching the semiconductor film of the substrate 6 to be processed is converted into a spot-shaped light beam illuminating only a predetermined area, and the light intensity distribution of the reverse peak pattern distributed at the same period is obtained. The light intensity distribution of the two-stage reverse peak pattern as shown in FIG. In the light intensity distribution of the two-stage reverse peak pattern, the light intensity is almost 0 at a point corresponding to the phase shift unit 4e so as to correspond to the light intensity distribution of the reverse peak pattern described above. The light intensity increases in a parabolic manner and reaches a predetermined value. That is, the position where the light intensity distribution of the two-stage reverse peak pattern becomes the minimum is determined by the position of the phase shift unit 4e.

In each modified example of the first embodiment, the light intensity distribution of the two-step reverse peak pattern is the above-described light intensity distribution of the concave pattern and the light intensity distribution of the concave pattern in the yz direction. The intermediate portion between the adjacent inverse peak pattern portions increases almost monotonically along the x direction and the y direction, as shown in FIG. In addition, the light intensity distribution of the two-step reverse peak pattern has an inflection point at which the slope decreases between the reverse peak pattern portion and the concave pattern portion above.

As in the first embodiment, when the light beam having the light intensity distribution of the two-step reverse peak pattern is irradiated on the substrate 6 in each of the modified examples, the point where the light intensity becomes minimum, that is, almost zero Crystal nuclei are formed at portions corresponding to points (points corresponding to the phase shift portion 4e). More specifically, a crystal nucleus is generated at a position with a large inclination in the light intensity distribution of the reverse peak pattern. Polycrystal is generated at the center of the reverse peak pattern portion, and then the crystal outside the nucleus grows as a crystal. The position where the crystal grows is generally a position with a large inclination.

Next, lateral growth is started from the crystal nucleus along the x direction where the light intensity gradient (that is, the temperature gradient) is large. In the light intensity distribution of the two-step reverse peak pattern, since there is substantially no portion where the light intensity decreases in the middle part, the lateral growth reaches the peak from the crystal nucleus without stopping halfway, realizing a large crystal growth can do. In particular, in the first embodiment, since there is an inflection point where the inclination decreases between the inverse peak pattern portion and the concave pattern portion above, the light beam having the light intensity distribution of the two-stage inverse peak pattern is processed. When the semiconductor film of the substrate 6 is irradiated, it is crystallized in a wide area extending from the center to the width of the light intensity distribution of the two-step reverse peak pattern. Therefore, by making the width dimension of the light intensity distribution of the two-step reverse peak pattern equal to the pixel pitch of the liquid crystal, a single crystal can be generated for each pixel.

As described above, in each modification of the first embodiment, it is possible to realize sufficient lateral growth from crystal nuclei and generate a crystallized semiconductor film having a large grain size. Since the crystal generated by the crystallization apparatus according to the first embodiment has a large grain size, the crystal has high electron mobility in the lateral growth direction (x direction). Therefore, by arranging the source and drain of the transistor in the direction of lateral growth, a transistor with excellent characteristics can be manufactured.

In the third modification, light incident on the microlens array 13 is wavefront-divided by a large number of microlens elements 13a, and the light beam condensed via each microlens element 13a is formed into a spot. Therefore, most of the light supplied from the illumination optical system 2 can contribute to crystallization of only a desired transistor region, and crystallization with good light efficiency can be realized.

In the third modification, the refraction surface 13b of the microlens element 13a of the microlens array 13 has a spherical shape, but may have a shape having different curvatures in the x direction and the y direction. If the curvatures of the refraction surface 13b in the x direction and the y direction are different, the spot-shaped light beam region becomes elliptical. Since the major axis and the minor axis of the elliptical shape correspond to the width dimension of the light intensity distribution of the two-step reverse peak pattern in the x direction and the y direction, when the spot-like light beam region is formed in the elliptical shape. , The gradient of the light intensity in the reverse peak pattern portion differs between the x direction and the y direction. Therefore, by setting the curvature of the refraction surface 13b, the degree of lateral growth can be changed along each direction.

In the third modification, a microlens array 13 as a wavefront splitting element has a plurality of optical elements (microlens elements) 13a arranged two-dimensionally, and each optical element 13a has a quadratic curved surface. Has a two-dimensional light condensing function via the refracting surface 13b. However, without being limited to this, for example, a micro cylindrical lens array 13 ′ as shown in FIG. 21 may be used. The micro cylindrical lens array 13 'has a plurality of optical elements 13'a arranged one-dimensionally in a predetermined direction, and each optical element 13'a is one-dimensionally collected in a predetermined direction. It has a refractive surface 13'b having an optical function. In this case, it is desirable to use a transmission filter 15 as shown in FIG. 22 in accordance with the use of the micro cylindrical lens array 13 '.

The transmission filter 15 includes, for example, an elongated rectangular central region 15a having a transmittance of 50%, and a pair of semicircular peripheral regions 15b having a transmittance of approximately 100% and sandwiching the central region 15a. And The longitudinal direction of the central region 15a of the transmission filter 15 and the longitudinal direction of each minute cylindrical lens element 13'a of the micro cylindrical lens array 13 'are set to correspond optically. The central region 15a is defined by substantially parallel strings, but is not limited thereto, and may have another shape.

The light beam incident on the micro cylindrical lens array 13 ′ is wavefront divided by a large number of minute cylindrical lens elements 13 ′ a, and the light beam condensed via each minute cylindrical lens element A slit-shaped (linear) light beam surrounding the transistor region is formed.

Therefore, the light intensity distribution of the slit-like light beam irradiated on the substrate 6 to be processed has a profile of a two-step reverse peak pattern as shown in FIG. Along with a uniform profile. In other words, the light beam transmitted through the micro cylindrical lens array 13 'and the transmission filter 15 and applied to the substrate 6 to be processed has a light intensity distribution as shown in FIG.

When the substrate 6 is irradiated with a light beam having a light intensity distribution of a two-stage reverse peak pattern as shown in FIG. 23, a crystal nucleus is formed at a point where the light intensity is minimized, that is, at a point substantially zero, Next, lateral growth is started from this crystal nucleus along a direction having a light intensity gradient (lateral direction in FIG. 22). In the light intensity distribution of the two-stage reverse peak pattern as shown in FIG. 23, since there is substantially no portion where the light intensity decreases in the middle part, the lateral growth reaches the peak without stopping halfway from the crystal nucleus, Large crystal growth can be realized.

In the third modification, the refracting surfaces of the microlens array 13 and the microcylindrical lens array 13 'may be formed into a continuous curved surface or may be formed into a step. In addition, without being limited to a continuous curved surface or a multi-stage approximation thereof, the divided wavefront element can be configured as a “kinoform” in which a range of 0 to 2π is turned back as a phase difference. Further, the function may be realized by the refractive index distribution of the optical material without providing a refraction surface to the divided wavefront element. In this case, a conventional technique such as a photopolymer whose refractive index is modulated by light intensity or ion exchange of glass can be used. Alternatively, a split wavefront element may be realized using a hologram or a diffractive optical element.

In the first embodiment and each of the modifications, the second imaging optical system 5 is interposed on the optics between the phase shift mask 4 and the substrate 6 to be processed. Since the distance from the image optical system 5 is relatively large, the phase shift mask 4 is not contaminated due to the ablation of the substrate 6 to be processed. Therefore, good crystallization can be realized without being affected by ablation in the substrate 6 to be processed.

Further, in the first embodiment and each of the modifications, since the distance between the substrate 6 and the second imaging optical system 5 is relatively large, the substrate 6 and the second imaging optical system 5 are secured. It is easy to adjust the positional relationship between the substrate 6 to be processed and the second imaging optical system 5 by introducing detection light for position detection into the optical path between the substrate and the second imaging optical system 5.

FIG. 24 is a diagram schematically showing a crystallization apparatus according to the second embodiment of the present invention. The second embodiment has a configuration similar to that of the first embodiment. However, in the second embodiment, the second imaging optical system 5 is placed on the optical path between the phase shift mask 4 and the substrate 6 to be processed. Is basically different from the first embodiment in that Hereinafter, the second embodiment will be described by focusing on the differences from the first embodiment. In FIG. 21, the illustration of the internal configuration of the illumination optical system 2 is omitted for clarity of the drawing.

As shown in FIG. 24, in the second embodiment, the phase shift mask 4 and the substrate 6 to be processed are arranged in parallel and close to each other (for example, several μm to several hundred μm). Further, the surface of the processing target substrate 6 is disposed so as to be optically conjugate with the emission surface of the transmission type amplitude modulation mask 1 via the first imaging optical system 3. When the transmission type amplitude modulation mask 1 is not interposed, the phase shift mask 4 converts a light beam having a uniform light intensity distribution into an inverse light having the smallest light intensity in a region corresponding to the phase shift portion 4e as shown in FIG. 7A. It has a function of converting a light beam having a light intensity distribution of a peak pattern. The width dimension of the light intensity distribution of the reverse peak pattern changes in proportion to the half power of the distance between the phase shift mask 4 and the substrate 6 (that is, the defocus amount).

In the second embodiment, as in the first embodiment, the light beam having the light intensity distribution of the two-step reverse peak pattern is formed by the action of both the transmission type amplitude modulation mask 1 and the phase shift mask 4. Since irradiation is performed on the semiconductor film of No. 6, lateral growth reaches the peak from the crystal nucleus without stopping halfway, and a crystallized semiconductor film having a large grain size can be generated. Note that, instead of the transmission type amplitude modulation mask 1, an aperture type amplitude modulation mask 11, a light converging / diverging element 12, and a micro lens array 13 and a transmission filter 14 are used as modified examples of the second embodiment. be able to.

FIG. 25 is a view schematically showing a crystallization apparatus according to the third embodiment of the present invention. The third embodiment has a configuration similar to that of the first embodiment. However, in the third embodiment, the phase shift surface of the phase shift mask 4 and the surface of the processing target substrate 6 correspond to the second imaging optics. This is basically different from the first embodiment in that they are arranged so as to have an optically conjugate relationship via the system 5. Hereinafter, the third embodiment will be described by focusing on the differences from the first embodiment. In FIG. 25, the illustration of the internal configuration of the illumination optical system 2 is omitted for clarity of the drawing.

As shown in FIG. 25, the phase shift surface of the phase shift mask 4 and the surface of the substrate to be processed 6 are arranged in an optically conjugate relationship via the second imaging optical system 5. The surface of the substrate 6 to be processed is optically conjugate with the exit surface of the transmission type amplitude modulation mask 1 via the first imaging optical system 3 and the second imaging optical system 5. Are located.

The imaging optical system 5 according to the third embodiment has an aperture stop 5a, which is arranged on the pupil plane of the imaging optical system 5. The aperture stop 5a has a plurality of aperture stops having different sizes of apertures (light transmitting portions), and the plurality of aperture stops are configured to be convertible with respect to an optical path. Alternatively, the aperture stop 5a may have an iris stop capable of continuously changing the size of the opening. The size of the aperture of the aperture stop 5a (that is, the image-side numerical aperture of the imaging optical system 5) is such that a periodic two-step reverse peak pattern light intensity distribution is generated on the semiconductor film of the substrate 6 to be processed. Is set to It is preferable that the width dimension of the light intensity distribution of the two-stage reverse peak pattern is set to be equal to the pixel pitch of the liquid crystal.

幅 The width dimension of the light intensity distribution of the reverse peak pattern formed on the semiconductor film of the substrate 6 to be processed by the operation of the phase shift mask 4 is substantially equal to the resolution R2 of the second imaging optical system 5. The resolution R2 of the second imaging optical system 5 is defined by R2 = kλ / NA2, where λ is the wavelength of the used light and NA2 is the image-side numerical aperture of the second imaging optical system 5. Here, the constant k is a value close to 1 depending on the specification of the illumination optical system 2 for illuminating the phase shift mask 4, the degree of coherence of the light beam supplied from the light source, and the definition of the resolution. As described above, in the third embodiment, when the image-side numerical aperture NA of the second imaging optical system 5 is reduced and the resolution of the second imaging optical system 5 is reduced, the light intensity distribution of the inverse peak pattern is reduced. The width dimension increases.

In other words, the inverse peak pattern portion of the light intensity distribution of the light beam converted on the phase shift plane has a narrow width on the phase shift plane and has a suitable width on a plane separated from the phase shift plane to some extent. . In the third embodiment, since the light intensity distribution on the phase shift surface is transferred to the semiconductor film of the processing target substrate 6 at a low resolution by the second imaging optical system 5, the light beam irradiated on the processing target substrate 6 is used. The reverse peak pattern portion of the light intensity distribution has a suitable width dimension on the semiconductor film of the substrate 6 to be processed.

Further, in the third embodiment, the second imaging optical system 5 is interposed on the optics between the phase shift mask 4 and the substrate 6 to be processed, and the substrate 6 and the second imaging optical system 5 are interposed. Is kept relatively large, so that the phase shift mask 4 is not contaminated due to ablation of the substrate 6 to be processed. Therefore, good crystallization can be realized without being affected by ablation in the substrate 6 to be processed.

Further, in the third embodiment, since the distance between the processing target substrate 6 and the second imaging optical system 5 is relatively large, the distance between the processing target substrate 6 and the second imaging optical system 5 is large. It is easy to introduce detection light for position detection onto the optical path and adjust the positional relationship between the processing target substrate 6 and the second imaging optical system 5.

In each of the above embodiments, the phase shift mask 4 is composed of four rectangular regions corresponding to phases of 0, π / 2, π, and 3π / 2, but is not limited thereto. Various modifications of the phase shift mask 4 are possible. For example, it is also possible to use a phase shift mask 4 having an intersection (phase shift portion) composed of three or more phase shift lines and having an integral value of the complex transmittance of a circular area centered on this intersection substantially zero. Good. Further, as shown in FIG. 26, a circular step corresponding to the phase shift portion is provided, and the phase difference between the transmitted light at the circular step and the transmitted light around the circular step is set to π. Alternatively, a phase shift mask 4 may be used.

The light intensity distribution can be calculated at the design stage, but it is desirable to observe and confirm the actual light intensity distribution on the surface to be processed (surface to be exposed). For this purpose, the surface to be processed may be enlarged by an optical system and input by an image pickup device such as a CCD. When the used light is ultraviolet light, the optical system is restricted, so that a fluorescent plate may be provided on the surface to be processed to convert the light into visible light.

FIG. 27 shows a step of manufacturing an electronic device using the crystallization apparatus of each embodiment. As shown in FIG. 27A, a base film 21 (for example, a 50 nm-thick SiN film and a 100 nm-thick SiO2 laminated film) is formed on an insulating substrate 20 (for example, alkali glass, quartz glass, plastic, polyimide, or the like). And the like, and an amorphous semiconductor film 22 (for example, Si, Gc, SiGe or the like having a thickness of about 50 nm to 200 nm) are formed by a chemical vapor deposition method, a sputtering method, or the like, thereby forming the substrate 6 to be processed. Prepare

(4) A part or all of the surface of the formed amorphous semiconductor film 22 is irradiated with a laser beam 23 (for example, a KrF excimer laser beam, a XeCl excimer laser beam, or the like) using the above-described crystallization apparatus. Since the crystallization apparatus according to each embodiment of the present invention irradiates a light beam having a light intensity distribution of a two-step reverse peak pattern, as shown in FIG. A polycrystalline semiconductor film or a single-crystallized semiconductor film 24 having a crystal with a larger grain size than the generated polycrystalline semiconductor film is generated.

When the amorphous semiconductor film 22 has a relatively large surface and one irradiation by the crystallization device irradiates only a part of the surface, crystallization of the entire surface of the amorphous semiconductor film 22 is performed as follows. This is performed by moving the crystallization apparatus and the amorphous semiconductor film 22 in two directions which are relatively perpendicular to each other.

For example, the crystallizer can be moved in two directions orthogonal to the amorphous semiconductor film 22, and the surface of the amorphous semiconductor film 22 may be irradiated with a light beam while moving the crystallizer. . Alternatively, the substrate to be processed provided with the amorphous semiconductor film 22 is mounted on a stage movable in two orthogonal directions, and by moving this stage with respect to a fixed crystallization apparatus, The surface of the amorphous semiconductor film 22 may be irradiated with a light beam. Alternatively, in a crystallization apparatus supported by an arm that can move in only one direction, a processing target substrate provided with the amorphous semiconductor film 22 is moved in a direction perpendicular to the crystallization apparatus. Alternatively, the surface of the amorphous semiconductor film 22 may be irradiated with a light beam by moving the crystallization apparatus and the substrate to be processed in two directions that are relatively perpendicular to each other.

Next, as shown in FIG. 27C, the polycrystalline semiconductor film or the single-crystallized semiconductor film 24 is processed into an island-shaped semiconductor film 25 using a photolithography technique, and a gate insulating film 26 having a thickness of 20 nm to A 100 nm SiO2 film is formed by using a chemical vapor deposition method, a sputtering method, or the like. Further, as shown in FIG. 27D, a gate electrode 27 (for example, silicide or MoW) is formed, and impurity ions 28 (phosphorus and P-channel transistors in the case of an N-channel transistor) are formed using the gate electrode 27 as a mask. In this case, boron is implanted. After that, annealing is performed in a nitrogen atmosphere (for example, at 450 ° C. for one hour) to activate the impurities.

Next, as shown in FIG. 27E, an interlayer insulating film 29 is formed, a contact hole is formed, and a source electrode 33 and a drain electrode 34 connected to the source 31 and the drain 32 connected by the channel 30 are formed. At this time, the channel 30 is formed in accordance with the position of the large-grain crystal of the polycrystalline semiconductor film or the single-crystallized semiconductor film 24 generated in the steps shown in FIGS. 27A and 27B.

Through the above steps, a polycrystalline transistor or a single-crystallized semiconductor transistor can be formed. The thin film transistor manufactured in this manner can be applied to a driving circuit of a display device such as a liquid crystal display or an EL (electroluminescence) display, and an integrated circuit such as a memory (SRAM or DRAM) or a CPU.

It is a figure showing roughly composition of a crystallization device concerning a 1st embodiment of the present invention. FIG. 2 is a diagram schematically illustrating an internal configuration of the illumination optical system in FIG. 1. FIG. 3 is a diagram illustrating a configuration and an operation of the transmission type amplitude modulation mask according to the first embodiment. FIG. 6 is a diagram illustrating a manufacturing process of the transmission type amplitude modulation mask according to the first embodiment. FIG. 2 is a perspective view showing a configuration of a basic unit portion of a phase shift mask. FIG. 5B is a top view showing the arrangement of the basic unit of the phase shift mask shown in FIG. 5A. It is a figure which shows the structure of another basic unit part of a phase shift mask perspectively. FIG. 3 is a diagram illustrating a basic operation of the phase shift mask according to the first embodiment. FIG. 4 is a diagram illustrating a light intensity distribution of a light beam transmitted through a transmission type amplitude modulation mask and a phase shift mask, which is obtained on a substrate to be processed in an xz plane. FIG. 3 is a diagram showing a light intensity distribution of a light beam transmitted through a transmission type amplitude modulation mask and a phase shift mask, which is obtained on a substrate to be processed in a yz plane. FIG. 7B is a diagram three-dimensionally showing the light intensity distribution shown in FIGS. 7A and 7B. It is a figure which shows schematically the crystallization apparatus which concerns on the 1st modification of 1st Embodiment. FIG. 3 is a top view of the aperture-type amplitude modulation mask and a diagram illustrating the operation of the aperture-type amplitude modulation mask. It is a figure which shows schematically the crystallization apparatus which concerns on the 2nd modification of 1st Embodiment. FIG. 3 is a side view showing the light-collecting / diverging element and a diagram for explaining the operation of the light-diverging element. It is a figure which shows the condensing and diverging element which has a step-shaped refraction surface. FIG. 9 is a diagram illustrating a simulation result regarding a light intensity distribution of a concave pattern on a light beam obtained on a phase shift mask. Light intensity distribution when the resolution of the first imaging optical system is set to a certain low level It is a figure which shows schematically the crystallization apparatus which concerns on the 3rd modification of 1st Embodiment. FIG. 15 is a diagram schematically illustrating the illumination optical system of FIG. 14. FIG. 4 is a diagram schematically illustrating a configuration of a transmission filter arranged on an illumination pupil plane or in the vicinity thereof. It is a figure which shows the basic unit part of a micro lens array roughly. FIG. 4 is a diagram illustrating a light intensity distribution of a light beam on a rear focal plane by the action of both a transmission filter and a microlens array. FIG. 4 is a diagram illustrating a light intensity distribution obtained on a substrate to be processed by a cooperative action of a transmission filter, a microlens array, and a phase shift mask. FIG. 20 is a diagram three-dimensionally showing the light intensity distribution shown in FIG. 19. It is a figure showing the micro cylindrical lens array concerning the 3rd modification. It is a figure showing a modification transmission filter concerning a 3rd modification. FIG. 14 is a diagram illustrating a light intensity distribution of a light beam transmitted through a transmission filter and a micro cylindrical lens array according to a third modification. It is a figure showing roughly the crystallization device concerning a 2nd embodiment of the present invention. It is a figure showing roughly the crystallization device concerning a 3rd embodiment of the present invention. FIG. 9 is a diagram illustrating a modification of the phase shift mask. 4 shows a step of manufacturing an electronic device using the crystallization apparatus of each embodiment.

Explanation of reference numerals

DESCRIPTION OF SYMBOLS 1 ... Transmission type | mold amplitude modulation mask, 2 ... Illumination optical system, 2a ... Light source, 2b ... Beam expander, 2c, 2e ... Fly-eye lens, 2d, 2f ... Condenser optical system, 3 ... 1st imaging optical system, 4 ... Phase shift mask, 5 ... Second imaging optical system, 6 ... Substrate to be processed, 7 ... Substrate stage, 11 ... Aperture type amplitude modulation mask, 12 ... Condensing and diverging element, 13 ... Micro lens array, 14, 15 ... Transmission filter.

Claims (29)

An illumination system for illuminating a phase shift mask, wherein light having a light intensity distribution of a reverse peak pattern having the smallest light intensity in a region corresponding to a phase shift portion of the phase shift mask is polycrystalline semiconductor film or amorphous semiconductor film. In a crystallization apparatus that generates a crystallized semiconductor film by irradiating
Optics for forming a light intensity distribution of a concave pattern in which the light intensity is the smallest in the region corresponding to the phase shift portion and the light intensity increases toward the periphery thereof on a predetermined surface based on the light from the illumination system. Components,
A crystal comprising an imaging optical system for setting a surface of the polycrystalline semiconductor film or the amorphous semiconductor film or a conjugate plane thereof and the predetermined plane in an optically conjugate relationship. Device. The crystallization apparatus according to claim 1, wherein the optical member is a transmission type amplitude modulation mask having a transmittance distribution according to a light intensity distribution of a concave pattern to be formed on the predetermined surface. The transmission type amplitude modulation mask has a light transmission portion having a constant thickness and a light absorption portion having a thickness distribution according to a light intensity distribution of a concave pattern to be formed on the predetermined surface. The crystallization apparatus according to claim 2, wherein 4. The crystallization apparatus according to claim 3, wherein the light absorbing section has a sinusoidal surface as a whole. 5. The crystallization apparatus according to claim 4, wherein the generally sinusoidal surface is formed in a continuous curved shape or a step shape. The crystallization apparatus according to claim 1, wherein the optical member is an aperture-type amplitude modulation mask having an aperture ratio distribution according to a light intensity distribution of a concave pattern to be formed on the predetermined surface. The crystallization apparatus according to claim 6, wherein the aperture type amplitude modulation mask has a large number of minute transmission regions or a large number of minute light shielding regions, or a therapy therefor. The crystallization apparatus according to claim 7, wherein the size of the minute transmission region and the minute light shielding region is set to be substantially smaller than the resolution of the imaging optical system. 9. The crystallization apparatus according to claim 7, wherein the imaging optical system is a reduction type optical system. The optical member includes, on the predetermined surface, a region where a light beam is diverged and illuminated corresponding to the phase shift unit and a region where a light beam is collected and illuminated corresponding to the periphery of the phase shift unit. The crystallization apparatus according to claim 1, wherein the crystallization apparatus is a light converging / diverging element that is generated. The crystallization apparatus according to claim 10, wherein the condensing / diverging element has a diverging / refracting surface for diverging the light beam and a converging / refracting surface for condensing the light beam. The crystallization apparatus according to claim 11, wherein the divergent refraction surface and the converging refraction surface form a sinusoidal refraction surface as a whole. 13. The crystallization apparatus according to claim 12, wherein the generally sinusoidal refraction surface is formed in a continuous curved shape or a step shape. The optical member includes a light intensity distribution forming element for forming a predetermined light intensity distribution having a higher light intensity at the periphery than at the center in or near the pupil plane of the illumination system, and a plurality of light beams supplied from the illumination system. 2. A wavefront splitting device for splitting a wavefront into a plurality of light beams, and condensing each of the wavefront-divided light beams on a region corresponding to the phase shift unit on the predetermined surface. Crystallization equipment. 15. The crystallization apparatus according to claim 14, wherein the wavefront splitting element has a plurality of optical elements having a light collecting function. The predetermined light intensity distribution has a circular central region having a relatively small light intensity, and an annular peripheral region having a relatively large light intensity formed so as to surround the central region. The crystallization apparatus according to claim 14 or 15, wherein the crystallization apparatus is used. The predetermined light intensity distribution has a central region having a relatively small light intensity elongated in a predetermined direction and a peripheral region having a relatively large light intensity formed to surround or sandwich the central region. The crystallization apparatus according to claim 14 or 15, wherein: 15. The crystallization apparatus according to claim 14, wherein the light intensity distribution forming element has a transmission filter having a predetermined light transmittance distribution disposed at or near the illumination pupil plane. The crystallization apparatus according to claim 1, wherein a phase shift surface of the phase shift mask is formed on a surface opposite to the illumination system side. The light intensity distribution applied to the polycrystalline semiconductor film or the amorphous semiconductor film includes a reverse peak pattern region having the smallest light intensity in a region corresponding to a phase shift portion of the phase shift mask, and the reverse peak pattern region. A concave pattern region in which the light intensity increases from to the periphery, and an inflection point having a slope decreasing toward the periphery between the reverse peak pattern region and the concave pattern region. Item 2. A crystallization apparatus according to Item 1. The crystallization apparatus according to claim 1, wherein the polycrystalline semiconductor film or the amorphous semiconductor film and the phase shift mask are arranged substantially in parallel and close to each other. A second imaging optical system disposed in an optical path between the polycrystalline semiconductor film or the amorphous semiconductor film and the phase shift mask;
The surface of the polycrystalline semiconductor film or the amorphous semiconductor film is set at a predetermined distance along the optical axis from a plane optically conjugate with the phase shift mask via the second imaging optical system. The crystallization apparatus according to claim 1, wherein: A second imaging optical system disposed in an optical path between the polycrystalline semiconductor film or the amorphous semiconductor film and the phase shift mask;
The surface of the polycrystalline semiconductor film or the amorphous semiconductor film is set to a plane optically conjugate with the phase shift mask via the second imaging optical system,
The crystallization apparatus according to claim 1, wherein an image-side numerical aperture of the second imaging optical system is set to a required value for generating a light intensity distribution of the reverse peak pattern. Illuminating the phase shift mask, and irradiating the polycrystalline semiconductor film or the amorphous semiconductor film with light having a light intensity distribution of a reverse peak pattern having the smallest light intensity in a region corresponding to the phase shift portion of the phase shift mask. In a crystallization method for producing a crystallized semiconductor film,
Based on the light from the illumination system, a light intensity distribution of a concave pattern in which the light intensity is the smallest and the light intensity increases toward the periphery in a region corresponding to the phase shift portion is formed on a predetermined surface,
A crystallization method comprising: setting an optically conjugate relationship between a surface of the polycrystalline semiconductor film or the amorphous semiconductor film or a conjugate plane thereof and the predetermined plane via an imaging optical system. 25. The crystallization method according to claim 24, wherein the polycrystalline semiconductor film or the amorphous semiconductor film and the phase shift mask are arranged substantially in parallel and close to each other. Disposing a second imaging optical system in an optical path between the polycrystalline semiconductor film or the amorphous semiconductor film and the phase shift mask;
A surface of the polycrystalline semiconductor film or the amorphous semiconductor film is set at a predetermined distance from a plane optically conjugate with the phase shift mask along an optical axis of the second imaging optical system. The crystallization method according to claim 24, wherein Disposing a second imaging optical system in an optical path between the polycrystalline semiconductor film or the amorphous semiconductor film and the phase shift mask;
Setting the image-side numerical aperture of the second imaging optical system to a required value for generating the light intensity distribution of the inverse peak pattern;
25. The surface according to claim 24, wherein a surface of the polycrystalline semiconductor film or the amorphous semiconductor film is set on a plane optically conjugate with the phase shift mask via the second imaging optical system. Crystallization method. A thin film transistor produced by the crystallization method according to claim 24. A display device comprising the thin film transistor according to claim 28.

Images