Thick film circuits with conductive components formed using different conductive elements and related methods
View Patent ↗Disclosed herein are a variety of embodiments of thick film circuits with conductive components formed using different conductive elements and related methods for forming such circuits. One embodiment consistent with the present disclosure includes a multi-level thick film circuit formed on a substrate and having a first layer disposed on the substrate. The first layer may include a first conductive component formed using a first conductive element. The first conductive element may be a precious metal. The circuit may further include a second layer having a second conductive component. The second conductive component may be formed using a second conductive element. In one embodiment, the second conductive element may be a base metal. At least a portion of the first conductive element may directly contact at least a portion of the second conductive element such that the first layer is in electrical communication with the second layer.
1. A method of forming a multi-level thick film circuit, comprising:
forming a first layer disposed on a substrate, the first layer comprising a first conductive component formed of a first conductive element, the first conductive element comprising a precious metal;
firing the substrate and the first layer in a first atmosphere during a first firing process, the first atmosphere comprising oxygen;
forming a second layer comprising a second conductive component formed of a second conductive element, the second layer conductive element comprising a base metal; and
firing the substrate, the first layer, and the second layer in a second atmosphere during a second firing process, the second atmosphere comprising an inert atmosphere;
wherein the second layer is at least partially disposed directly on top of the first layer and the first layer is in electrical communication with the second layer.
2. The method of claim 1 , wherein the first conductive element comprises silver.
3. The method of claim 1 , wherein, wherein the second conductive element comprises copper.
4. The method of claim 1 , further comprising:
forming a dielectric layer to electrically separate a third conductive component from one of the first conductive component and the second conductive component.
5. The method of claim 1 , wherein the first firing process is performed at approximately 850° C.±20° C.
6. The method of claim 1 , wherein the second firing process is performed between approximately 600° C. and 700° C.±10° C.
7. The method of claim 1 , further comprising:
forming a plurality of additional layers; and
forming a plurality of dielectric layers configured to electrically separate at least a portion of the plurality of additional layers;
wherein each layer disposed below an uppermost dielectric layer is formed using the first conductive element and each layer disposed above the uppermost dielectric material is formed using the second conductive element.
8. The method of claim 1 , further comprising:
forming a plurality of additional layers comprising a plurality of conductive components; and
forming a plurality of dielectric layers configured to electrically separate at least one of the plurality of conductive components from at least one other of the plurality of conductive components;
wherein each conductive component disposed directly in contact with any of the plurality of dielectric layers is formed using the first conductive element.
9. The method of claim 1 , wherein forming the second layer comprises:
applying a thick film ink to the multi-level thick film circuit, the thick film ink comprising:
an organic portion; and
an inorganic portion dispersed in the organic portion defining a paste,
wherein the inorganic portion comprises metallic copper powder, cupric oxide, and elemental boron.
10. A method of forming a multi-level thick film circuit, comprising:
forming a first layer disposed on a substrate, the first layer comprising a first conductive component formed of a first conductive element, the first conductive element comprising a precious metal;
firing the substrate and the first layer in a first atmosphere at a first temperature during a first firing process;
forming a second layer comprising a second conductive component formed of a second conductive element, the second layer conductive element comprising a base metal; and
firing the substrate, the first layer, and the second layer in a second atmosphere at a second temperature during a second firing process, the first temperature being greater than the second temperature;
wherein the second layer is at least partially disposed directly on top of the first layer and the first layer is in electrical communication with the second layer.
11. The method of claim 10 , wherein the first atmosphere comprises oxygen.
12. The method of claim 10 , wherein the second atmosphere comprises an inert atmosphere.
13. The method of claim 10 , wherein the first firing process is performed at approximately 850° C.±20° C.
14. The method of claim 10 , wherein the second firing process is performed between approximately 600° C. and 700° C.±10° C.