Method and resulting structure using silver for lcos devices

Abstract

An LCOS device includes a semiconductor substrate and a plurality of MOS transistors that is formed on a portion of the semiconductor substrate. The LCOS device includes a first dielectric layer overlying the plurality of MOS transistors and a patterned metal layer overlying the first dielectric layer. The patterned metal layer exposes portions of the first dielectric layer that form borders surrounding the patterned metal layer, wherein the patterned metal layer includes a plurality of electrodes. The LCOS device further includes a second dielectric layer overlying the exposed portions of the first dielectric layer. In an embodiment, the patterned metal layer comprises a silver bearing material. Each of the plurality of electrodes has an upper surface having a surface roughness of less than 5 Angstrom and a surface reflectivity of greater than 97% for a light having a wavelength of 500 nanometers and greater.

1 . An LCOS device comprising:
 a semiconductor substrate;   a plurality of MOS transistor devices formed on a portion of the semiconductor substrate;   a first dielectric layer overlying the plurality of MOS transistors;   a patterned silver metal layer overlying the first dielectric layer and exposing portions of the first dielectric layer, the exposed portions forming borders surrounding one of a plurality of patterns of the patterned silver metal layer, the one of the plurality of patterns corresponding to a pixel element; and   a second dielectric layer overlying the patterned silver metal layer and the exposed portions of the first dielectric layer;   wherein the patterned silver metal layer forms a plurality of electrodes, each of the electrodes includes a polished upper surface corresponding to the pixel element.   
     
     
         2 . The LCOS device of  claim 1 , wherein the polished upper surface comprises a surface roughness of less than 5 Angstroms. 
     
     
         3 . The LCOS device of  claim 2 , wherein the polished upper surface comprises a surface reflectivity of greater than 97% for a visible light having a wavelength of 500 nanometers and greater. 
     
     
         4 . The LCOS device of  claim 2 , wherein the polished upper surface comprises a surface reflectivity of greater than 95% for a visible light having a wavelength of 450 nanometers and greater. 
     
     
         5 . The LCOS device of  claim 2 , wherein the polished upper surface comprises a surface reflectivity of greater than 89% for a visible light having a wavelength of 400 nanometers. 
     
     
         6 . The LCOS device of  claim 1 , wherein the first dielectric layer comprises a single layer or multiple layers. 
     
     
         7 . The LCOS device of  claim 1 , wherein the second dielectric layer comprises a single layer or multiple layers. 
     
     
         8 . The LCOS device of  claim 1 , wherein the exposed portions of the first dielectric layer form borders surrounding the plurality of electrodes. 
     
     
         9 . The LCOS device of  claim 1 , wherein each one of the plurality of MOS transistors comprises a contact region configured to electrically couple with each of the plurality of electrodes. 
     
     
         10 . The LCOS device of  claim 1  further comprising a protective layer overlying the patterned metal layer, the protective layer being configured to keep the patterned metal layer free from any oxidation. 
     
     
         11 . An LCOS device comprising:
 a semiconductor substrate;   a plurality of MOS transistor devices formed on a portion of the semiconductor substrate;   a first dielectric layer overlying the plurality of transistor devices;   a first metal layer overlying the first dielectric layer;   a second dielectric layer overlying the first metal layer; and   a plurality of pixel regions made substantially of silver bearing material overlying the second dielectric layer;   wherein the pixel regions have a thickness ranging from about 2000 Angstroms to about 4000 Angstrom.   
     
     
         12 . The LCOS device of  claim 11 , wherein the pixel regions are provided by an electroplating process. 
     
     
         13 . The LCOS device of  claim 11 , wherein the pixel regions are provided using a PVD or CVD process. 
     
     
         14 . The LCOS device of  claim 11 , wherein the pixel regions are provided using a dual damascene process. 
     
     
         15 . The LCOS device of  claim 11 , wherein each of the pixel regions comprises a surface reflectivity of greater than 97% for a visible light having a wavelength of 500 nanometers and greater. 
     
     
         16 . The LCOS device of  claim 11 , wherein each of the pixel regions is maintained in an inert environment. 
     
     
         17 . The LCOS device of claim  claim 11  further comprising a protective layer overlying the plurality of pixel regions to maintain the silver bearing material free from any oxidation. 
     
     
         18 . The LCOS device of claim  claim 11  further comprising a liquid crystal layer overlying the protective layer. 
     
     
         19 . The LCOS device of  claim 18  further comprising:
 a transparent electrode layer overlying the liquid crystal layer; and 
 a glass layer overlying the transparent electrode layer.