Semiconductor device and method of fabricating the same

Abstract

There is provided a high quality liquid crystal panel having a thickness with high accuracy, which is designed, without using a particulate spacer, within a free range in accordance with characteristics of a used liquid crystal and a driving method, and is also provided a method of fabricating the same. The shape of a spacer for keeping a substrate interval constant is made such that it is a columnar shape, a radius R of curvature is 2 μm or less, a height H is 0.5 μm to 10 μm, a diameter is 20 μm or less, and an angle α is 65° to 115°. By doing so, it is possible to prevent the lowering of an opening rate and the lowering of light leakage due to orientation disturbance.

1 . (canceled) 
     
     
         2 . A display device comprising:
 a first substrate;   a first semiconductor layer over the first substrate, the first semiconductor layer comprising a channel formation region;   a first pixel electrode electrically connected to the first semiconductor layer;   a second semiconductor layer over the first substrate, the second semiconductor layer comprising a channel formation region;   a second pixel electrode electrically connected to the second semiconductor layer;   a second substrate over the first pixel electrode and the second pixel electrode; and   a photolithographic spacer between the first substrate and the second substrate,   wherein the photolithographic spacer overlaps with the first semiconductor layer, and   wherein no photolithographic spacer overlaps with the second semiconductor layer.   
     
     
         3 . The display device according to  claim 2 , further comprising:
 a gate electrode under the first semiconductor layer;   an insulating layer between the gate electrode and the first semiconductor layer;   a wiring over and electrically connected to the first semiconductor layer; and   an interlayer insulating layer over the wiring,   wherein the photolithographic spacer overlaps with the gate electrode, the insulating layer, the wiring, and the interlayer insulating layer.   
     
     
         4 . The display device according to  claim 2 , wherein the photolithographic spacer has a cross-section in which a value obtained by dividing a width of a second substrate side end portion of the photolithographic spacer by a width of a center portion of the photolithographic spacer is larger than or equal to 0.8 and smaller than or equal to 3. 
     
     
         5 . The display device according to  claim 2 , further comprising:
 a third semiconductor layer over the first substrate, the third semiconductor layer comprising a channel formation region; and   a third pixel electrode electrically connected to the third semiconductor layer,   wherein no photolithographic spacer overlaps with the third semiconductor layer, and   wherein the third pixel electrode is adjacent to the first pixel electrode and the second pixel electrode.   
     
     
         6 . The display device according to  claim 2 , wherein a sectional shape of the photolithographic spacer is a quadrilateral or a polygon having sides more than four. 
     
     
         7 . The display device according to  claim 2 , further comprising:
 a liquid crystal layer over the first pixel electrode and the second pixel electrode.   
     
     
         8 . The display device according to  claim 2 , wherein the channel formation region of each of the first semiconductor layer and the second semiconductor layer comprises silicon. 
     
     
         9 . A display device comprising:
 a first substrate;   a first semiconductor layer over the first substrate, the first semiconductor layer comprising a channel formation region;   a first pixel electrode electrically connected to the first semiconductor layer;   a second semiconductor layer over the first substrate, the second semiconductor layer comprising a channel formation region;   a second pixel electrode electrically connected to the second semiconductor layer;   a second substrate over the first pixel electrode and the second pixel electrode; and   a plurality of photolithographic spacers between the first substrate and the second substrate,   wherein a photolithographic spacer of the plurality of photolithographic spacers overlaps with the first semiconductor layer,   wherein no photolithographic spacer overlaps with the second semiconductor layer, and   wherein the plurality of photolithographic spacers are disposed at a density of 10 to 200/mm 2 .   
     
     
         10 . The display device according to  claim 9 , further comprising:
 a gate electrode under the first semiconductor layer;   an insulating layer between the gate electrode and the first semiconductor layer;   a wiring over and electrically connected to the first semiconductor layer; and   an interlayer insulating layer over the wiring,   wherein the photolithographic spacer overlaps with the gate electrode, the insulating layer, the wiring, and the interlayer insulating layer.   
     
     
         11 . The display device according to  claim 9 , wherein the photolithographic spacer has a cross-section in which a value obtained by dividing a width of a second substrate side end portion of the photolithographic spacer by a width of a center portion of the photolithographic spacer is larger than or equal to 0.8 and smaller than or equal to 3. 
     
     
         12 . The display device according to  claim 9 , further comprising:
 a third semiconductor layer over the first substrate, the third semiconductor layer comprising a channel formation region; and   a third pixel electrode electrically connected to the third semiconductor layer,   wherein no photolithographic spacer overlaps with the third semiconductor layer, and   wherein the third pixel electrode is adjacent to the first pixel electrode and the second pixel electrode.   
     
     
         13 . The display device according to  claim 9 , wherein a sectional shape of the photolithographic spacer is a quadrilateral or a polygon having sides more than four. 
     
     
         14 . The display device according to  claim 9 , wherein each of the plurality of photolithographic spacers is disposed for every six pixels. 
     
     
         15 . The display device according to  claim 9 , further comprising:
 a liquid crystal layer over the first pixel electrode and the second pixel electrode.   
     
     
         16 . The display device according to  claim 9 , wherein the channel formation region of each of the first semiconductor layer and the second semiconductor layer comprises silicon. 
     
     
         17 . A display device comprising:
 a first substrate;   a first semiconductor layer over the first substrate, the first semiconductor layer comprising a channel formation region;   a first pixel electrode electrically connected to the first semiconductor layer;   a second semiconductor layer over the first substrate, the second semiconductor layer comprising a channel formation region;   a second pixel electrode electrically connected to the second semiconductor layer;   a third semiconductor layer over the first substrate, the third semiconductor layer comprising a channel formation region;   a third pixel electrode electrically connected to the third semiconductor layer;   a second substrate over the first pixel electrode, the second pixel electrode and the third pixel electrode;   a photolithographic spacer between the first substrate and the second substrate;   a liquid crystal layer over the first pixel electrode, the second pixel electrode and the third pixel electrode;   a gate electrode under the first semiconductor layer;   an insulating layer between the gate electrode and the first semiconductor layer;   a wiring over and electrically connected to the first semiconductor layer;   an interlayer insulating layer over the wiring,   wherein the photolithographic spacer overlaps with the gate electrode, the insulating layer, the wiring, and the interlayer insulating layer,   wherein the photolithographic spacer overlaps with the first semiconductor layer,   wherein no photolithographic spacer overlaps with the second semiconductor layer,   wherein no photolithographic spacer overlaps with the third semiconductor layer,   wherein the third pixel electrode is adjacent to the first pixel electrode and the second pixel electrode, and   wherein the photolithographic spacer has a cross-section in which a value obtained by dividing a width of a second substrate side end portion of the photolithographic spacer by a width of a center portion of the photolithographic spacer is larger than or equal to 0.8 and smaller than or equal to 3, and a width of a first substrate side end portion of the photolithographic spacer by the width of the center portion of the photolithographic spacer is larger than or equal to 1 and smaller than or equal to 2.5.   
     
     
         18 . The display device according to  claim 17 , wherein a sectional shape of the photolithographic spacer is a quadrilateral or a polygon having sides more than four. 
     
     
         19 . The display device according to  claim 17 , wherein the channel formation region of each of the first semiconductor layer, the second semiconductor layer and the third semiconductor layer comprises silicon.