Method for forming thermoelectric device from particulate raw materials

Abstract

This invention relates to the formation manufacturing method for constructing a thermoelectric device, by dispensing a slurry composed of thermoelectric solids in a carrier fluid across a substrate. The process uses a mold to confine the slurry, and heat and pressure to cure the thermoelectric slurry into a solid. The specific method of curing the thermoelectric material is outlined, employing a new method of condensing the particulate solids into dense thermoelectric elements.

1 . A method for fabricating a thermoelectric device, comprising: forming a plurality of thermoelectric elements by deposition of thermoelectric precursor material into a plurality of cavities in a mold for said elements. 
   
   
       2 . The method of  claim 1  wherein the thermoelectric precursor material is thermoelectric solid particles dispersed in a carrier fluid. 
   
   
       3 . The method of  claim 1  wherein the thermoelectric precursor material is thermoelectric solid particles. 
   
   
       4 . The method of  claim 1  wherein the thermoelectric precursor material is treated with elevated temperature to form thermoelectric elements. 
   
   
       5 . The method of  claim 1  wherein the thermoelectric precursor material is treated with elevated pressure to form thermoelectric elements. 
   
   
       6 . The method of  claim 5  wherein where the elevated pressure is applied by submerging the device in a liquid or gas, and subjecting the device to elevated isostatic pressure. 
   
   
       7 . The method of  claim 1  wherein the thermoelectric precursor material is treated with elevated temperature and pressure to form thermoelectric elements. 
   
   
       8 . The method of  claim 7  wherein the elevated pressure is applied by submerging the device in a liquid or gas, and subjecting the device to elevated isostatic pressure. 
   
   
       9 . The method of  claim 1  wherein deposition of thermoelectric precursor material into a plurality of cavities includes using a dispensing head to deposit the precursor material into the cavities. 
   
   
       10 . The method of  claim 1  wherein deposition of thermoelectric precursor material into a plurality of cavities includes using a electrophoresis or dielectrophoresis to deposit the precursor material into the cavities. 
   
   
       11 . The method of  claim 1  wherein deposition of thermoelectric precursor material into a plurality of cavities includes forming a first mold layer having a first plurality of cavities using a electrophoresis or dielectrophoresis to deposit a precursor material of a first polarity into the cavities, removing the first mold layer, forming a second mold layer having a second plurality of cavities and locations different from locations of the first plurality of cavities, using a electrophoresis or dielectrophoresis to deposit a precursor material of a second polarity into the cavities, wherein the second polarity is opposite to the first polarity. 
   
   
       12 . The method of  claim 1  wherein the thermoelectric precursor material includes particles of thermoelectric material between 1 nanometer and 100 microns in size. 
   
   
       13 . A method for manufacturing thermoelectric devices, comprising:
 a) forming a bottom substrate;   b) forming bottom electrical interconnections on the bottom substrate;   c) forming one or more mold layers on the bottom electrical interconnections and the bottom substrate, the mold layer including an array of open cavities;   d) filling a first portion of the open cavities in the array with a p-type thermoelectric slurry;   e) filing a second portion of the open cavities in the array with an n-type thermoelectric slurry;   f) forming a capping layer on top of the mold layer and the filled cavities;   g) densifying and curing the n-type and p-type thermoelectric slurries in the filled cavities to form thermoelectric elements;   h) removing the capping layer; and   i) forming top electrical interconnections on top of the thermoelectric elements.   
   
   
       14 . The method of  claim 13  further comprising: forming a top substrate on top of the top electrical interconnection. 
   
   
       15 . The method of  claim 13 , wherein b) comprises forming and patterning electrically conducting materials. 
   
   
       16 . The method of  claim 13 , wherein the open cavities are formed by mechanical impressions from a negative mold or by lithography. 
   
   
       17 . The method of  claim 13 , wherein the thermoelectric slurry is formed by mixing particles of solid thermoelectric material with a carrier fluid. 
   
   
       18 . The method of  claim 17 , wherein d) comprises dispensing the thermoelectric slurry with a dispensing head composed of multiple heads in parallel. 
   
   
       19 . The method of  claim 17 , wherein g) comprises: removing the carrier fluid by applying heat or reducing the ambient pressure; submerging the device in a liquid or gas, and subjecting the device to elevated isostatic pressure; and annealing the device at high temperature. 
   
   
       20 . The method of  claim 13  wherein d) comprises dispensing the p-type slurry into the portion of the open cavities with a first dispensing head. 
   
   
       21 . The method of  claim 20  wherein e) comprises dispensing the n-type slurry into the remaining open cavities with a second dispensing head. 
   
   
       22 . The method of  claim 13  wherein d) comprises depositing the p-type slurry into a plurality of cavities includes using a electrophoresis or dielectrophoresis. 
   
   
       23 . The method of  claim 13  wherein e) comprises depositing the n-type slurry into a plurality of cavities includes using a electrophoresis or dielectrophoresis. 
   
   
       24 . The method of  claim 13  wherein d) through f) comprise: forming a first mold layer having a first plurality of cavities, depositing a precursor material of a first polarity into the cavities using a electrophoresis or dielectrophoresis, removing the first mold layer, forming a second mold layer having a second plurality of cavities and locations different from locations of the first plurality of cavities, depositing a precursor material of a second polarity into the cavities using electrophoresis or dielectrophoresis, wherein the second polarity is opposite to the first polarity. 
   
   
       25 . The method of  claim 24  wherein the slurry includes particles of thermoelectric material between 1 nanometer and 100 microns in size.