Method of forming semiconductor thin film and semiconductor thin film inspection apparatus

Abstract

A method of forming a semiconductor thin film includes the steps of: forming an amorphous semiconductor thin film on a substrate; forming a crystalline semiconductor thin film partially in each element region by applying laser light to the amorphous semiconductor thin film to selectively perform a heating process on the amorphous semiconductor thin film, thereby crystallizing the amorphous semiconductor thin film in a region irradiated with the laser light; and inspecting the crystallinity degree of the crystalline semiconductor thin film. The step of inspecting includes the steps of determining a contrast between the luminance of a crystallized region and the luminance of a non-crystallized region by applying light to the crystalline semiconductor thin film and the amorphous semiconductor thin film, and performing screening of the crystalline semiconductor thin film on the basis of the determined contrast.

1 . A method of forming a semiconductor thin film comprising the steps of:
 forming a non-crystalline film over a substrate; and   forming a crystalline semiconductor film in each element region by applying laser light to the non-crystalline film, thereby crystallizing the non-crystalline film in a region irradiated with the laser light.   
     
     
         2 . The method of  claim 1  comprising inspecting the crystallinity degree of the crystalline semiconductor film, the step of inspecting including:
 determining a contrast between the luminance of a crystallized film and the luminance of a non-crystalline film by applying light to the crystalline semiconductor film and the non-crystalline film, and 
 screening of the crystalline film on the basis of the determined contrast. 
 
     
     
         3 . The method of forming a semiconductor thin film according to  claim 2 , wherein in the step of performing screening, screening of the crystalline semiconductor thin film is performed through the use of a correlation between the determined contrast, irradiation intensity of light in the step of determining the contrast, and electrical characteristics obtained in the crystalline semiconductor thin film. 
     
     
         4 . The method of forming a semiconductor thin film according to  claim 3 , wherein screening of the crystalline semiconductor thin film is performed through the use of γ characteristics with a γ value=1 between the irradiation intensity and the contrast. 
     
     
         5 . The method of forming a semiconductor thin film according to  claim 3 , wherein γ characteristics between the irradiation intensity and the contrast are corrected so as to have a γ value=1, and then screening of the crystalline semiconductor thin film is performed through the use of the corrected γ characteristics. 
     
     
         6 . The method of forming a semiconductor thin film according to  claim 2 , wherein in the step of determining the contrast, a picked-up image of the crystalline semiconductor thin film and the amorphous semiconductor thin film is obtained on the basis of applied light, and then the contrast is determined on the basis of the picked-up image. 
     
     
         7 . The method of forming a semiconductor thin film according to  claim 6 , wherein a transmission image of the crystalline semiconductor thin film and the amorphous semiconductor thin film is obtained on the basis of transmitted light of the applied light, and then the contrast is determined on the basis of the transmission image. 
     
     
         8 . The method of forming a semiconductor thin film according to  claim 6 , wherein a reflection image of the crystalline semiconductor thin film and the amorphous semiconductor thin film is obtained on the basis of reflected light of the applied light, and then the contrast is determined on the basis of the reflection image. 
     
     
         9 . The method of forming a semiconductor thin film according to  claim 6 , wherein:
 a reference level measurement region for obtaining a reference image with respect to the picked-up image and a zero level measurement region for obtaining a zero level image corresponding to an offset component when obtaining the picked-up image and the reference image are arranged in predetermined positions on the substrate or a stage where the substrate is mounted;   in the step of determining the contrast, correction is performed on a luminance distribution of the obtained picked-up image through the use of the following expression, and then the contrast is determined; and   this relationship (luminance distribution of picked-up image after correction)={(luminance distribution of picked-up image before correction−luminance distribution of zero level image)/(luminance distribution of reference image−luminance distribution of zero level image)}×{average value of (luminance distribution of reference image−luminance distribution of zero level image)} exists.   
     
     
         10 . The method of forming a semiconductor thin film according to  claim 2 , wherein in the step of determining the contrast, spectrophotometric measurement is performed on the basis of light applied to a microscopic region to determine the contrast. 
     
     
         11 . The method of forming a semiconductor thin film according to  claim 2 , wherein in the step of determining the contrast, applied light is divided into a plurality of beams, and the luminance of the crystallized region and the luminance of the non-crystallized region are differentially amplified, and then the contrast is determined. 
     
     
         12 . The method of forming a semiconductor thin film according to  claim 2 , wherein in the step of determining the contrast, white light is used as applied light. 
     
     
         13 . The method of forming a semiconductor thin film according to  claim 1 , wherein in the step of determining the contrast, green light is used as applied light. 
     
     
         14 . The method of forming a semiconductor thin film according to  claim 2 , wherein in the step of determining the contrast, light with a shorter wavelength than that of blue light is used as applied light. 
     
     
         15 . The method of forming a semiconductor thin film according to  claim 1 , wherein in the step of forming the crystalline semiconductor thin film, the laser light is applied to a light-absorbing layer, thereby a heating process is performed indirectly on the non-crystalline film. 
     
     
         16 . The method of forming a semiconductor thin film according to  claim 1 , wherein in the step of forming the crystalline semiconductor thin film, the laser light is applied through the use of a laser diode light source. 
     
     
         17 . The method of forming a semiconductor thin film according to  claim 1 , wherein the crystalline semiconductor thin film is a film used to form a TFT (a thin film transistor). 
     
     
         18 . The method of forming a semiconductor thin film according to  claim 1 , wherein the crystalline semiconductor thin film and the non-crystalline film are Si (silicon) thin films. 
     
     
         19 . The method of forming a semiconductor thin film according to  claim 18 , wherein the crystalline semiconductor thin film is a polycrystalline Si thin film or a microcrystalline Si thin film. 
     
     
         20 . A semiconductor thin film inspection apparatus that is a crystallinity degree inspection apparatus used to form a crystalline semiconductor thin film, the crystalline semiconductor thin film being formed partially in each element region by applying laser light to a non-crystalline film on a substrate to selectively perform a heating process on the non-crystalline film, thereby crystallizing the amorphous semiconductor thin film in a region irradiated with the laser light, the semiconductor thin film inspection apparatus comprising:
 a stage on which the substrate is mounted, the substrate including the crystalline semiconductor thin film formed thereon;   a light source that applies light to the crystalline semiconductor thin film and the non-crystalline film;   a derivation section that determines a contrast between the luminance of a crystallized region and the luminance of a non-crystallized region on the basis of light emitted from the light source; and   a screening section that performs screening of the crystalline semiconductor thin film on the basis of the contrast determined by the derivation section.   
     
     
         21 . The semiconductor thin film inspection apparatus according to  claim 20 , further comprising:
 a control section that performs control for relatively displacing the light source and an optical system of the derivation section with respect to the substrate mounted on the stage.