Double-sided electrode structure and patterning process thereof
A patterning process for forming a double-sided electrode structure includes: providing a substrate having two opposite surfaces, wherein a first photo-sensitive layer and a second photo-sensitive layer are respectively formed on the opposite surfaces; forming a first metal nanowire layer on the first photo-sensitive layer and a second metal nanowire layer on the second photo-sensitive layer; and performing a double-sided lithography process. The lithography process includes: performing an exposure process to define a removing area and a remaining area on both of the first and the second photo-sensitive layers; and removing the first and second photo-sensitive layers and the first and second metal nanowire layers in the defined removing areas by a developer solution, thereby patterning the first and second metal nanowire layers.
1. A patterning method for forming a double-sided electrode structure, comprising:
providing a substrate, wherein the substrate has two opposite surfaces, and a first photo-sensitive layer and a second photo-sensitive layer are respectively formed on the opposite surfaces;
forming a first metal nanowire layer on the first photo-sensitive layer and a second metal nanowire layer on the second photo-sensitive layer, wherein the first metal nanowire layer and the second metal nanowire layer are made of a plurality of metal nanowires; and
performing a double-sided lithography process, comprising:
performing an exposure process to define a removing area and a remaining area on the first photo-sensitive layer and a removing area and a remaining area on the second photo-sensitive layer; and
removing the first and second photo-sensitive layers and the metal nanowires of the first and second metal nanowire layers in the defined removing areas by a developer solution, thereby patterning the first and second metal nanowire layers to form a first electrode and a second electrode on the opposite surfaces, respectively.
2. The patterning method according to claim 1 , wherein the first and second photo-sensitive layers are made of photoresist with substantially the same photo sensitivity.
3. The patterning method according to claim 2 , wherein the performing the exposure process comprises:
providing a first light source corresponding to the first photo-sensitive layer and a second light source corresponding to the second photo-sensitive layer, wherein a first light emitted from the first light source and a second light emitted from the second light source are substantially in the same wavelength range;
wherein the first photo-sensitive layer absorbs more than about 80% of a total energy of the first light emitted from the first light source, and the second photo-sensitive layer absorbs more than about 80% of a total energy of the second light emitted from the second light source.
4. The patterning method according to claim 2 , wherein the performing the exposure process comprises:
providing a first light source corresponding to the first photo-sensitive layer and a second light source corresponding to the second photo-sensitive layer, wherein a first light emitted from the first light source and a second light emitted from the second light source are substantially in the same wavelength range;
wherein the first and second photo-sensitive layers comprise about 0.1%-10% of a light absorption additive by weight.
5. The patterning method according to claim 4 , wherein a concentration of the light absorption additive is about 1%-3% by weight, a light transmittance of the first photo-sensitive layer with respect to the first light emitted from the first light source is less than about 30%, and a light transmittance of the second photo-sensitive layer with respect to the second light emitted from the second light source is less than about 30%.
6. The patterning method according to claim 1 , wherein the first and second photo-sensitive layers are made of photoresists with different photo sensitivities.
7. The patterning method according to claim 6 , wherein the performing the exposure process comprises:
providing a first light source corresponding to the first photo-sensitive layer and a second light source corresponding to the second photo-sensitive layer, wherein a first light emitted from the first light source and a second light emitted from the second light source are in different wavelength ranges.
8. The patterning method according to claim 1 , further comprising:
forming a protective layer; and
forming a peripheral circuit, wherein the peripheral circuit is electrically connected with the first electrode and the second electrode.
9. A double-sided electrode structure, comprising:
a substrate having opposite first and second surfaces; and
a first photo-sensitive layer and a first metal nanowire layer stacked on the first surface, and a second photo-sensitive layer and a second metal nanowire layer stacked on the second surface;
wherein a removing area and a remaining area are defined on the first photo-sensitive layer and a removing area and a remaining area are defined on the second photo-sensitive layer by an exposure process, the first photo-sensitive layer and the first metal nanowire layer in the removing area on the first photo-sensitive layer are removed to define a first electrode on the first surface, and the second photo-sensitive layer and the second metal nanowire layer in the removing area on the second photo-sensitive layer are removed to define a second electrode on the second surface.
10. The double-sided electrode structure according to claim 9 , wherein the first and second photo-sensitive layers are made of photoresists with the same photo sensitivity, the first photo-sensitive layer absorbs more than about 80% of a total energy of a first light emitted from a first light source, and the second photo-sensitive layer absorbs more than about 80% of a total energy of a second light emitted from a second light source.
11. The double-sided electrode structure according to claim 9 , wherein the first and second photo-sensitive layers are made of photoresists with the same photo sensitivity, and the first and second photo-sensitive layers comprise about 0.1%-10% of a light absorption additive by weight.
12. The double-sided electrode structure according to claim 11 , wherein a concentration of the light absorption additive is about 1%-3% by weight, a light transmittance of the first photo-sensitive layer with respect to a first light emitted from a first light source is less than about 30%, and a light transmittance of the second photo-sensitive layer with respect to a second light emitted from a second light source is less than about 30%.
13. The double-sided electrode structure according to claim 9 , wherein the first and second photo-sensitive layers are made of photoresists with different photo sensitivities.
14. The double-sided electrode structure according to claim 9 , wherein the first photo-sensitive layer and the first metal nanowire layer in the remaining area have the same pattern, and the second photo-sensitive layer and the second metal nanowire layer in the remaining area have the same pattern.
15. The double-sided electrode structure according to claim 9 , wherein the first electrode comprises a plurality of sensing electrodes extending along a first direction, the second electrode comprises a plurality of sensing electrodes extending along a second direction, and the sensing electrodes of the first and second electrodes are located in a display area.
16. The double-sided electrode structure according to claim 15 , further comprising a peripheral circuit disposed in a peripheral area, wherein the peripheral circuit is electrically connected with the sensing electrodes of the first and second electrodes.
17. The double-sided electrode structure according to claim 9 , further comprising a protective layer covering the first electrode and the second electrode.