Method of laser irradiation, laser irradiation apparatus, and method of manufacturing a semiconductor device
First Claim
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1. A method of manufacturing a semiconductor device comprising:
- emitting a laser beam having a first cross section perpendicular to a propagation direction of the laser beam;
expanding the laser beam along a first direction to increase the cross section of the laser beam along the first direction;
regulating an optical path length of the expanded laser beam along the first direction using a concave lens;
condensing the laser beam along a second direction orthogonal to the first direction; and
crystallizing a semiconductor film comprising amorphous silicon by irradiating the semiconductor film with the laser beam while relatively moving the surface with respect to the laser beam along a third direction orthogonal to the first direction wherein the laser beam has a second cross section on the surface, the second cross section being larger than the first cross section along the first direction and shorter than the first direction along the third direction;
patterning the crystallized semiconductor film into a plurality of semiconductor lavers, each including a region to become a channel forming region of a thin film transistor.
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Abstract
If an optical path length of an optical system is reduced and a length of a laser light on an irradiation surface is increased, there occurs curvature of field which is a phenomenon that a convergent position deviates depending on an incident angle or incident position of a laser light with respect to a lens. To avoid this phenomenon, an optical element having a negative power such as a concave lens or a concave cylindrical lens is inserted to regulate the optical path length of the laser light and a convergent position is made coincident with a irradiation surface to form an image on the irradiation surface.
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Citations
40 Claims
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1. A method of manufacturing a semiconductor device comprising:
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emitting a laser beam having a first cross section perpendicular to a propagation direction of the laser beam; expanding the laser beam along a first direction to increase the cross section of the laser beam along the first direction; regulating an optical path length of the expanded laser beam along the first direction using a concave lens; condensing the laser beam along a second direction orthogonal to the first direction; and crystallizing a semiconductor film comprising amorphous silicon by irradiating the semiconductor film with the laser beam while relatively moving the surface with respect to the laser beam along a third direction orthogonal to the first direction wherein the laser beam has a second cross section on the surface, the second cross section being larger than the first cross section along the first direction and shorter than the first direction along the third direction; patterning the crystallized semiconductor film into a plurality of semiconductor lavers, each including a region to become a channel forming region of a thin film transistor. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8)
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9. A method of manufacturing a semiconductor device comprising:
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emitting a laser beam having a first cross section perpendicular to a propagation direction of the laser beam; expanding the laser beam along a first direction by dividing the laser beam into a plurality of laser beams and superposing the plurality of laser beams along the first direction whereby a uniformity of the laser beam is homogenized along the first direction; regulating an optical path length of the expanded laser beam along the first direction using a concave lens; condensing the laser beam along a second direction orthogonal to the first direction; and crystallizing a semiconductor film comprising amorphous silicon by irradiating the semiconductor film with the laser beam while relatively moving the surface with respect to the laser beam in a third direction orthogonal to the first direction wherein the laser beam has a second cross section on the surface, the second cross section being larger than the first cross section along the first direction and shorter than the first direction along the third direction; patterning the crystallized semiconductor film into a plurality of semiconductor layers, each including a region to become a channel forming region of a thin film transistor. - View Dependent Claims (10, 11, 12, 13, 14, 15, 16)
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17. A method of manufacturing a semiconductor device comprising:
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emitting a laser beam having a first cross section perpendicular to a propagation direction of the laser beam; expanding the laser beam along a first direction by dividing the laser beam into a plurality of laser beams using a cylindrical lens array and superposing the plurality of laser beams along the first direction using a cylindrical lens whereby a uniformity of the laser beam is homogenized along the first direction; regulating an optical path length of the expanded laser beam along the first direction using a concave lens; condensing the laser beam along a second direction orthogonal to the first direction; and crystallizing a semiconductor film comprising amorphous silicon by irradiating the semiconductor film with the laser beam while relatively moving the surface with respect to the laser beam along a third direction orthogonal to the first direction wherein the laser beam has a second cross section on the surface, the second cross section being larger than the first cross section along the first direction and shorter than the first direction along the third direction; patterning the crystallized semiconductor film into a plurality of semiconductor layers. each including a region to become a channel forming region of a thin film transistor. - View Dependent Claims (18, 19, 20, 21, 22, 23, 24)
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25. A method of manufacturing a semiconductor device comprising:
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emitting a laser beam having a first cross section perpendicular to a propagation direction of the laser beam; expanding the laser beam along a first direction by dividing the laser beam into a plurality of laser beams and superposing the plurality of laser beams along the first direction whereby a uniformity of the laser beam is homogenized along the first direction; regulating an optical path length of the expanded laser beam along the first direction using a concave lens; dividing the laser beam along a second direction orthogonal to the first direction into a plurality of laser beams and superposing the plurality of laser beams along the second direction whereby a uniformity of the laser beam along the second direction is homogenized; and condensing the laser beam along the second direction after the uniformity of the laser beam is homogenized; crystallizing a semiconductor film comprising amorphous silicon by irradiating the semiconductor film with the laser beam while relatively moving the surface with respect to the laser beam along a third direction orthogonal to the first direction wherein the laser beam has a second cross section on the surface, the second cross section being larger than the first cross section along the first direction and shorter than the first direction along the third direction patterning the crystallized semiconductor film into a plurality of semiconductor layers, each including a region to become a channel forming region of a thin film transistor. - View Dependent Claims (26, 27, 28, 29, 30, 31, 32)
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33. A method of manufacturing a semiconductor device comprising:
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emitting a laser beam having a first cross section perpendicular to a propagation direction of the laser beam; expanding the laser beam along a first direction by dividing the laser beam into a plurality of laser beams using a first cylindrical lens array and superposing the plurality of laser beams along the first direction using a first cylindrical lens whereby a uniformity of the laser beam is homogenized along the first direction; regulating an optical path length of the expanded laser beam along the first direction using a concave lens; dividing the laser beam along a second direction orthogonal to the first direction into a plurality of laser beams using a second cylindrical lens array and superposing the plurality of laser beams along the second direction using a second cylindrical lens whereby a uniformity of the laser beam along the second direction is homogenized; condensing the laser beam along a second direction orthogonal to the first direction; and crystallizing a semiconductor film comprising amorphous silicon by irradiating the semiconductor film with the laser beam while relatively moving the surface with respect to the laser beam along a third direction orthogonal to the first direction wherein the laser beam has a second cross section on the surface, the second cross section being larger than the first cross section along the first direction and shorter than the first direction along the third direction; patterning the crystallized semiconductor film into a plurality of semiconductor layers, each including a region to become a channel forming region of a thin film transistor. - View Dependent Claims (34, 35, 36, 37, 38, 39, 40)
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Specification