Reflective liquid crystal display device

Abstract

A reflective liquid crystal display device has at least one anti-reflection layer made of a metallic film and a silicon oxynitride film that exhibits low reflectivity against light beams which may otherwise be incident into pixel switching transistors. At least one pair of pixel switching transistor and a capacitor are formed on a semiconductor substrate. The transistor and the capacitor are electrically isolated from each other. A first interlayer insulating layer is formed on the transistor and the capacitor. A wiring layer is formed on the first interlayer insulating layer. A second interlayer insulating layer is formed over the wiring layer. A light shielding layer is formed on the second interlayer insulating layer. A third interlayer insulating layer is formed over the light shielding layer. At least one pixel electrode is formed on the third interlayer insulating layer. A common electrode is formed over the pixel electrode. A light-transmissive substrate is formed on the common electrode. A liquid crystal layer is provided between the pixel electrode and the common electrode. An anti-reflection layer is formed on, at least, either the wiring layer or the light shielding layer. The anti-reflection layer is a double layer of a metallic film and a silicon oxynitride film that exhibits a refraction index different from a refraction index of the third interlayer insulating layer.

1 . A reflective liquid crystal display device comprising: 
 a semiconductor substrate;    at least one pair of pixel switching transistor and a capacitor formed on the semiconductor substrate and electrically isolated from each other;    a first interlayer insulating layer formed on the pixel switching transistor and the capacitor;    a wiring layer formed on the first interlayer insulating layer;    a second interlayer insulating layer formed over the wiring layer;    a light shielding layer formed on the second interlayer insulating layer, the light shielding layer being divided into a plurality of layer portions by gaps;    a third interlayer insulating layer formed over the light shielding layer;    at least one pixel electrode formed on the third interlayer insulating layer;    a common electrode formed over the pixel electrode;    a liquid crystal layer provided between the pixel electrode and the common electrode;    a light-transmissive substrate formed on the common electrode; and    at least one anti-reflection layer formed on the light shielding layer, the anti-reflection layer covering the gaps of the light shielding layer.    
   
   
       2 . The reflective liquid crystal display device according to  claim 1 , wherein the anti-reflection layer includes a film having Si.  
   
   
       3 . The reflective liquid crystal display device according to  claim 2 , wherein the film having Si is a silicon oxynitride film.  
   
   
       4 . The reflective liquid crystal display device according to  claim 3 , wherein the refraction index of the silicon oxynitride film is in the range from 1.7 to 1.9.  
   
   
       5 . The reflective liquid crystal display device according to  claim 3 , wherein a thickness of the silicon oxynitride film is in the range from 400 to 600 Å.  
   
   
       6 . A reflective liquid crystal display device comprising: 
 a semiconductor substrate;    at least one pair of pixel switching transistor and a capacitor formed on the semiconductor substrate and electrically isolated from each other;    a first interlayer insulating layer formed on the pixel switching transistor and the capacitor;    a wiring layer formed on the first interlayer insulating layer, the wiring layer being divided into a plurality of layer portions by gaps;    a second interlayer insulating layer formed over the wiring layer;    a light shielding layer formed on the second interlayer insulating layer;    a third interlayer insulating layer formed over the light shielding layer;    at least one pixel electrode formed on the third interlayer insulating layer;    a common electrode formed over the pixel electrode;    a liquid crystal layer provided between the pixel electrode and the common electrode;    a light-transmissive substrate formed on the common electrode; and    at least one anti-reflection layer formed on the wiring layer, the anti-reflection layer covering the gaps of the wiring layer.    
   
   
       7 . The reflective liquid crystal display device according to  claim 6 , wherein the anti-reflection layer includes a film having Si.  
   
   
       8 . The reflective liquid crystal display device according to  claim 7 , wherein the film having Si is a silicon oxynitride film.  
   
   
       9 . The reflective liquid crystal display device according to  claim 8 , wherein the refraction index of the silicon oxynitride film is in the range from 1.7 to 1.9.  
   
   
       10 . The reflective liquid crystal display device according to  claim 8 , wherein a thickness of the silicon oxynitride film is in the range from 400 to 600 Å.  
   
   
       11 . A reflective liquid crystal display device comprising: 
 a semiconductor substrate;    at least one pair of pixel switching transistor and a capacitor formed on the semiconductor substrate and electrically isolated from each other;    a first interlayer insulating layer formed on the pixel switching transistor and the capacitor;    a wiring layer formed on the first interlayer insulating layer, the wiring layer being divided into a plurality of layer portions by gaps;    a second interlayer insulating layer formed over the wiring layer;    a light shielding layer formed on the second interlayer insulating layer, the light shielding layer being divided into a plurality of layer portions by gaps;    a third interlayer insulating layer formed over the light shielding layer;    at least one pixel electrode formed on the third interlayer insulating layer;    a common electrode formed over the pixel electrode;    a liquid crystal layer provided between the pixel electrode and the common electrode;    a light-transmissive substrate formed on the common electrode;    a first anti-reflection layer formed on the wiring layer, the first anti-reflection layer covering the gaps of the wiring layer; and    a second anti-reflection layer formed on the light shielding layer, the second anti-reflection layer including Si and covering the gaps of the light shielding layer.    
   
   
       12 . The reflective liquid crystal display device according to  claim 11 , wherein each anti-reflection layer includes a film having Si.  
   
   
       13 . The reflective liquid crystal display device according to  claim 12 , wherein each film having Si is a silicon oxynitride film.  
   
   
       14 . The reflective liquid crystal display device according to  claim 13 , wherein the refraction index of the silicon oxynitride film is in the range from 1.7 to 1.9.  
   
   
       15 . The reflective liquid crystal display device according to  claim 13 , wherein a thickness of the silicon oxynitride film is in the range from 400 to 600 Å.