# US 12,004,424 B2 · Flexible thermoelectric device

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- Number: US 12,004,424 B2
- Document ID: US12004424B2
- Status: Granted
- Kind: B2
- Application number: 17/779,623
- Filed: 2019-12-06
- Published: 2023-01-19
- Granted: 2024-06-04
- Earliest claimed: 2019-12-06
- Assignees: 3M Innovative Properties Company
- Applicants: 3M Innovative Properties Company
- Inventors: Ravi Palaniswamy; Antonny Flor; Sheldon B. Ruiz; Milind B. Sabade
- Web page: https://patentgrep.com/patent/US12004424B2

## CPC

- H10N 10/01: Manufacture or treatment
- H10N 10/13: characterised by the heat-exchanging means at the junction
- H10N 10/17: characterised by the structure or configuration of the cell or thermocouple forming the device
- H10N 10/852: comprising tellurium, selenium or sulfur
- H10N 10/855: comprising compounds containing boron, carbon, oxygen or nitrogen
- H10N 10/8556: {comprising compounds containing germanium or silicon}
- H10N 10/81: Structural details of the junction
- H10N: ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR

## Abstract

The present disclosure relates to a method of fabricating a thermoelectric device. The method includes disposing a metal layer on a dielectric layer to form a sub-assembly, forming patterned circuits on the metal layer, forming blind vias in the dielectric layer, fabricating first thermoelectric elements in a first series of blind vias, and fabricating second thermoelectric elements in a second series of blind vias to form thermoelectric units with the first thermoelectric elements and the patterned circuits. The sub-assembly is configured to be joined to an adjacent sub-assembly along a first direction, and the first and second thermoelectric elements of each thermoelectric unit are aligned in a second direction substantially perpendicular to the first direction. The present disclosure further relates to a thermoelectric device which includes a plurality of thermoelectric units forming a strip extending in a first direction.

## Claims

### Claim 1

A method of fabricating a thermoelectric device, the method comprising:
disposing a metal layer on a dielectric layer to form a sub-assembly;
forming patterned circuits on the metal layer;
forming a first and second series of blind vias in the dielectric layer;
fabricating first thermoelectric elements in the first series of blind vias; and
fabricating second thermoelectric elements in the second series of blind vias to form thermoelectric units comprising pairs of individual first thermoelectric elements and individual second thermoelectric elements electrically coupled via the patterned circuits,
wherein the sub-assembly is configured to be joined to an adjacent sub-assembly along a first direction, and wherein fabricating the first and second thermoelectric elements comprises aligning the first and second thermoelectric elements of each thermoelectric unit in a second direction substantially perpendicular to the first direction.

### Claim 2 (depends on 1)

The method as claimed in claim 1, wherein forming the patterned circuits comprises:
forming a first patterned photo-resist layer on the metal layer;
disposing a metal on the metal layer based on the first patterned photo-resist layer; and
removing the photo-resist layer and non-functional metal from the sub-assembly.

### Claim 3 (depends on 2)

The method as claimed in claim 2, wherein forming the first patterned photo-resist layer on the metal layer comprises:
providing a first photomask; and
aligning registration spots of the first photomask with corresponding registration holes of the metal layer.

### Claim 4 (depends on 1)

The method as claimed in claim 1, wherein forming the blind vias comprises:
forming a second patterned photo-resist layer on the dielectric layer; and
removing the dielectric layer.

### Claim 5 (depends on 4)

The method as claimed in claim 4, wherein forming the second patterned photo-resist layer on the dielectric layer comprises:
providing a second photomask; and
aligning registration spots of the second photomask with corresponding registration holes of the dielectric layer.

### Claim 6 (depends on 1)

The method as claimed in claim 1, further comprising joining multiple sub-assemblies to form an assembly extending in the first direction before forming the patterned circuits and blind vias.

### Claim 7 (depends on 6)

The method as claimed in claim 6, wherein joining the multiple sub-assemblies comprises aligning markers on an edge of one sub-assembly with corresponding markers on an adjoining edge of another sub-assembly.

### Claim 8 (depends on 6)

The method as claimed in claim 6, further comprising forming through vias in the dielectric layer at the step of forming the first and second series of blind vias to form a gap between the two adjacent sub-assemblies.

### Claim 9 (depends on 1)

The method as claimed in claim 1, wherein fabricating the first thermoelectric elements in the first series of blind vias and fabricating the second thermoelectric elements in the second series of blind vias comprises screen printing of the first and second thermoelectric elements.

### Claim 10 (depends on 1)

The method as claimed in claim 1, further comprising providing metal contacts to connect the thermoelectric units within the sub-assembly in series.

### Claim 11 (depends on 10)

The method as claimed in claim 10, wherein ends of adjacent sub-assemblies are connected in series in a serpentine arrangement.

### Claim 12 (depends on 1)

The method as claimed in claim 1, wherein the dielectric layer is made of a material selected from a group consisting of polyimide, polyesters, thermoplastic polyimide, polyamide, polyolefin film, liquid crystalline polymer film, and flexible FR4 based film.

### Claim 13 (depends on 1)

The method as claimed in claim 1, wherein the first thermoelectric element is made of a material selected from the group consisting of bismuth telluride, silicon germanium, calcium cobalt oxides based materials, sodium cobalt oxides based materials, and strontium titanium oxides based materials.

### Claim 14 (depends on 1)

The method as claimed in claim 1, wherein the second thermoelectric element is made of a material selected from the group consisting of antimony telluride, lead tellurides, and Mg2X (X=Si, Ge, and Sn) based materials.