Patterning a thick film paste in surface features
AssigneeE. I. Du Pont de Nemours and Company
InventorLap-Tal Andrew Cheng
Life of this patent
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Abstract
This invention relates to a method for the fabrication of electrical and electronic devices using a photoresist deposited in pre-existing through holes in a device structure and a thick film paste, and to the devices made by such method. The method allows thick film paste deposits in the corners of the holes. This invention also relates to devices made with thick film pastes that are patterned using a diffusion layer made from residual photoresist deposits in a hole.
Claims18
A method of depositing a thick-film paste in a through hole having a side wall, comprising
- (a) providing a stack of layers that comprises a base layer and an external layer disposed on the surface of the base layer, or on the surface of one or more layers intermediate between the external layer and the base layer, wherein the external layer comprises a plurality of through holes that pass through the external layer and any intermediate layers to expose the surface of the base layer;
- (b) coating the external layer with photoresist material to provide a layer of photoresist material across the external layer and in the through holes;
- (c) solidifying the photoresist material;
- (d) flood irradiating the photoresist material to convert to a soluble form (i) the solidified photoresist material on the external layer, and (ii) the solidified photoresist material down to a selected depth of the layer of photoresist material in the through holes;
- (e) developing the photoresist material to remove the solidified photoresist material (i) from the external layer, and (ii) from within the through holes down to the selected depth of the layer, wherein removal of photoresist material from within the through holes exposes the surface of the base layer;
- (f) coating the external layer with a thick-film paste comprising a solvent to provide a layer of thick-film paste across the external layer and in the through holes;
- (g) solubilizing the photoresist material with the solvent in the locations in the through holes at which the thick-film paste contacts the photoresist material;
- and
- (h) developing the thick-film paste to remove it from all locations except those in which the thick-film paste has contacted the photoresist material.
An electron emitting apparatus comprising (a) a substrate;
- (b) a first conductive layer disposed on the substrate;
- (c) a dielectric layer disposed on the first conductive layer;
- (d) a second conductive layer disposed on the dielectric layer;
- (e) a plurality of through holes, each having a side wall(s), that pass through the second conductive layer and the dielectric layer to expose the surface of the first conductive layer;
- and (f) an electron emitting material disposed at the junction of the side wall(s) of a through hole and the surface of the first conductive layer.
An electronic device comprising a multi-layer stack of layers, and a patterned deposit on exposed portion(s) of a surface of a layer thereof of a mixture of a photoresist material and a thick film paste material.
Dependencies are inferred from the claim text.