Semiconductor device including semiconductor thin film, which is subjected to heat treatment to have alignment mark, crystallizing method for the semiconductor thin film, and crystallizing apparatus for the semiconductor thin film

Abstract

Exact alignment of a recrystallized region, which is to be formed in an amorphous or polycrystalline film, is facilitated. An alignment mark is formed, which is usable in a step of forming an electronic device, such as a thin-film transistor, in the recrystallized region. In addition, in a step of obtaining a large-grain-sized crystal-phase semiconductor from a semiconductor film, a mark structure that is usable as an alignment mark in a subsequent step is formed on the semiconductor film in the same exposure step. Thus, the invention includes a light intensity modulation structure that modulates light and forms a light intensity distribution for crystallization, and a mark forming structure that modulates light and forms a light intensity distribution including a pattern with a predetermined shape, and also forms a mark indicative of a predetermined position on a crystallized region.

1 . A semiconductor film formation substrate comprising a support substrate and a semiconductor film formed on a surface of the support substrate, wherein the semiconductor film includes: 
 an alignment mark part that is formed by first laser irradiation at a predetermined position; and    a recrystallized region with a large grain size, which is formed by second laser irradiation.    
   
   
       2 . The semiconductor film formation substrate according to  claim 1 , further comprising an undercoat layer that is formed of an insulating material between the support substrate and the semiconductor film.  
   
   
       3 . The semiconductor film formation substrate according to  claim 1 , further comprising a protection film that is formed of an insulating material on a surface of the semiconductor film.  
   
   
       4 . The semiconductor film formation substrate according to  claim 2 , further comprising a protection film that is formed of an insulating material on a surface of the semiconductor film.  
   
   
       5 . A light modulation element comprising: 
 a first light intensity modulation structure that modulates light and forms a light intensity distribution for crystallization; and    a second light intensity modulation structure that is formed integral with, or separately from, the first light intensity modulation structure, modulates light and forms a light intensity distribution for formation of an alignment mark that is indicative of a predetermined position on a crystallized region.    
   
   
       6 . The light modulation element according to  claim 5 , wherein the second light intensity modulation structure includes a pattern that is capable of lowering a light intensity to an arbitrary value, compared to a light intensity for crystallization.  
   
   
       7 . The light modulation element according to  claim 5 , wherein the second light intensity modulation structure is a structure that varies a light intensity at a time of image focusing.  
   
   
       8 . The light modulation element according to  claim 7 , wherein the structure that varies a light intensity at a time of image focusing selectively varies a phase modulation value.  
   
   
       9 . The light modulation element according to  claim 8 , wherein the structure that varies a light intensity at a time of image focusing varies an area that is capable of transmitting light.  
   
   
       10 . The light modulation element according to  claim 6 , wherein the second light intensity modulation structure varies a light transmission amount of a pattern that is capable of transmitting light.  
   
   
       11 . The light modulation element according to  claim 7 , wherein the second light intensity modulation structure varies a light transmission amount of a pattern that is capable of transmitting light.  
   
   
       12 . The light modulation element according to  claim 9 , wherein the second light intensity modulation structure selectively varies a thickness or a distance, by which light is transmitted.  
   
   
       13 . The light modulation element according to  claim 9 , wherein the second light intensity modulation structure varies a ratio between an area of a part with a first phase modulation value and an area of a part with a second phase modulation value.  
   
   
       14 . The light modulation element according to  claim 5 , wherein the second light intensity modulation structure is configured such that an area of a light transmissive region per unit area or an area of a region with a different phase per unit area is determined by a mesh-like or dot-like pattern.  
   
   
       15 . A light modulation element comprising two or more kinds of light intensity modulation regions that modulate light and form a predetermined light intensity distribution, 
 wherein at least one of the two or more kinds of light intensity modulation regions is composed of two kinds of basic patterns, a first basic pattern of the two kinds of basic patterns comprising a set of a light-blocking region and a light-transmissive region, and a second basic pattern of the two kinds of basic patterns comprising only a light-blocking region, or a set of a light-blocking region, whose ratio in area is greater than the light-blocking region of the first basic pattern, and a light-transmissive region, or    at least one of the two or more kinds of light intensity modulation regions includes a first basic pattern, which comprises a set of two or more kinds of phase modulation regions with different phase modulation values, and a second basic pattern, which comprises only a region with a single phase value, or a set of two or more kinds of phase modulation regions with different phase values, which have a ratio in area different from a ratio in area in the first basic pattern.    
   
   
       16 . An apparatus including a thin-film transistor formed in an amorphous or polycrystalline semiconductor film lying on a substrate that has a surface formed of an insulating material, the apparatus comprising, at least, an alignment mark including a region that is formed by subjecting the amorphous or polycrystalline semiconductor film to thermal metamorphism such that said region has optical characteristics in a reflective state, which are different from optical characteristics of the amorphous or polycrystalline semiconductor film, and a thin-film transistor provided in a region that is formed by partly single-crystallizing the amorphous or polycrystalline semiconductor film.