Flexible thin-film based thermoelectric device with sputter deposited layer of n-type and p-type thermoelectric legs

Abstract

A method includes sputter depositing pairs of N-type thermoelectric legs and P-type thermoelectric legs electrically in contact with one another on a flexible substrate having a dimensional thickness less than or equal to 25 μm. The method also includes forming a thermoelectric module with the sputter deposited pairs of the N-type thermoelectric legs and the P-type thermoelectric legs. Further, the method includes rendering the formed thermoelectric module flexible and less than or equal to 100 μm in dimensional thickness based on choices of fabrication processes with respect to layers of the formed thermoelectric module including the sputter deposited N-type thermoelectric legs and the P-type thermoelectric legs. The flexibility enables an array of thermoelectric modules, each of which is equivalent to the thermoelectric module formed on the flexible substrate, to be completely wrappable and bendable around a system element from which the array is configured to derive thermoelectric power.

What is claimed is: 
     
         1 . A method of a thin-film based thermoelectric module comprising:
 sputter depositing pairs of N-type thermoelectric legs and P-type thermoelectric legs electrically in contact with one another on a flexible substrate, the flexible substrate being one of: aluminum (Al) foil, a sheet of paper, teflon, plastic, a single-sided copper (Cu) clad laminate sheet, and a double-sided Cu clad laminate sheet, the flexible substrate having a dimensional thickness less than or equal to 25 μm;   forming the thin-film based thermoelectric module with the sputter deposited pairs of the N-type thermoelectric legs and the P-type thermoelectric legs; and   rendering the formed thin-film based thermoelectric module flexible and less than or equal to 100 μm in dimensional thickness based on choices of fabrication processes with respect to layers of the formed thin-film based thermoelectric module including the sputter deposited N-type thermoelectric legs and the P-type thermoelectric legs, the flexibility enabling an array of thin-film based thermoelectric modules, each of which is equivalent to the thin-film based thermoelectric module formed on the flexible substrate, to be completely wrappable and bendable around a system element from which the array of the thin-film based thermoelectric modules is configured to derive thermoelectric power, and a layer of the formed thin-film based thermoelectric module including the sputter deposited N-type thermoelectric legs and the P-type thermoelectric legs having a dimensional thickness less than or equal to 25 μm.   
     
     
         2 . The method of  claim 1 , comprising utilizing one of: a photomask and a hard mask with patterns corresponding to one of: the N-type thermoelectric legs and the P-type thermoelectric legs to aid the sputter deposition thereof. 
     
     
         3 . The method of  claim 1 , further comprising:
 printing and etching a design pattern of metal onto the flexible substrate to form electrically conductive pads, leads and terminals on the flexible substrate, the formed electrically conductive pads, the leads and the terminals having a dimensional thickness less than or equal to 18 μm;   additionally electrodepositing a seed metal layer comprising at least one of: Chromium (Cr), Nickel (Ni) and Gold (Au) directly on top of the formed electrically conductive pads, the leads and the terminals on the flexible substrate following the printing and etching thereof, the seed metal layer having a dimensional thickness less than or equal to 5 μm; and   sputter depositing the N-type thermoelectric legs and the P-type thermoelectric legs directly on top of the electrodeposited seed metal layer.   
     
     
         4 . The method of  claim 3 , further comprising sputter depositing a barrier metal layer comprising one of: Cr, Ni and Au on top of the sputter deposited pairs of the N-type thermoelectric legs and the P-type thermoelectric legs utilizing one of: another photomask and another hard mask to further aid metallization contact therewith, the barrier metal layer having a dimensional thickness less than or equal to 5 μm. 
     
     
         5 . The method of  claim 4 , further comprising depositing conductive interconnects on top of the sputter deposited barrier metal layer utilizing a hard mask to assist selective application thereof, the deposited conductive interconnects having a dimensional thickness less than or equal to 25 μm. 
     
     
         6 . The method of  claim 5 , further comprising depositing the conductive interconnects through screen printing conductive forms of ink on the sputter deposited barrier metal layer. 
     
     
         7 . The method of  claim 1 , further comprising encapsulating the formed thin-film based thermoelectric module with an elastomer to render the flexibility thereto, the elastomer encapsulation having a dimensional thickness less than or equal to 15 μm. 
     
     
         8 . The method of  claim 7 , comprising the elastomer being silicone, and wherein the method further comprises:
 loading the silicone with nano-size aluminum oxide (Al 2 O 3 ) powder to enhance thermal conductivity thereof to aid heat transfer across the formed thin-film based thermoelectric module.   
     
     
         9 . A method of a thin-film based thermoelectric module comprising:
 sputter depositing pairs of N-type thermoelectric legs and P-type thermoelectric legs electrically in contact with one another on a flexible substrate, the flexible substrate being one of: Al foil, a sheet of paper, teflon, plastic, a single-sided Cu clad laminate sheet, and a double-sided Cu clad laminate sheet, the flexible substrate having a dimensional thickness less than or equal to 25 μm;   forming the thin-film based thermoelectric module with the sputter deposited pairs of the N-type thermoelectric legs and the P-type thermoelectric legs;   rendering the formed thin-film based thermoelectric module flexible and less than or equal to 100 μm in dimensional thickness based on choices of fabrication processes with respect to layers of the formed thin-film based thermoelectric module including the sputter deposited N-type thermoelectric legs and the P-type thermoelectric legs, a layer of the formed thin-film based thermoelectric module including the sputter deposited N-type thermoelectric legs and the P-type thermoelectric legs having a dimensional thickness less than or equal to 25 μm; and   wrapping and bending an array of thin-film based thermoelectric modules, each of which is equivalent to the thin-film based thermoelectric module formed on the flexible substrate, completely around a system element from which the array of the thin-film based thermoelectric modules is configured to derive thermoelectric power in accordance with the flexibility thereof.   
     
     
         10 . The method of  claim 9 , comprising utilizing one of: a photomask and a hard mask with patterns corresponding to one of: the N-type thermoelectric legs and the P-type thermoelectric legs to aid the sputter deposition thereof. 
     
     
         11 . The method of  claim 9 , further comprising:
 printing and etching a design pattern of metal onto the flexible substrate to form electrically conductive pads, leads and terminals on the flexible substrate, the formed electrically conductive pads, the leads and the terminals having a dimensional thickness less than or equal to 18 μm;   additionally electrodepositing a seed metal layer comprising at least one of: Cr, Ni and Au directly on top of the formed electrically conductive pads, the leads and the terminals on the flexible substrate following the printing and etching thereof, the seed metal layer having a dimensional thickness less than or equal to 5 μm; and   sputter depositing the N-type thermoelectric legs and the P-type thermoelectric legs directly on top of the electrodeposited seed metal layer.   
     
     
         12 . The method of  claim 11 , further comprising sputter depositing a barrier metal layer comprising one of: Cr, Ni and Au on top of the sputter deposited pairs of the N-type thermoelectric legs and the P-type thermoelectric legs utilizing one of: another photomask and another hard mask to further aid metallization contact therewith, the barrier metal layer having a dimensional thickness less than or equal to 5 μm. 
     
     
         13 . The method of  claim 12 , further comprising depositing conductive interconnects on top of the sputter deposited barrier metal layer utilizing a hard mask to assist selective application thereof, the deposited conductive interconnects having a dimensional thickness less than or equal to 25 μm. 
     
     
         14 . The method of  claim 13 , further comprising depositing the conductive interconnects through screen printing conductive forms of ink on the sputter deposited barrier metal layer. 
     
     
         15 . The method of  claim 9 , further comprising encapsulating the formed thin-film based thermoelectric module with an elastomer to render the flexibility thereto, the elastomer encapsulation having a dimensional thickness less than or equal to 15 μm. 
     
     
         16 . A method of a thin-film based thermoelectric device comprising:
 sputter depositing pairs of N-type thermoelectric legs and P-type thermoelectric legs electrically in contact with one another on a flexible substrate, the flexible substrate being one of: Al foil, a sheet of paper, teflon, plastic, a single-sided Cu clad laminate sheet, and a double-sided Cu clad laminate sheet, the flexible substrate having a dimensional thickness less than or equal to 25 μm;   forming the thin-film based thermoelectric device out of an array of thermoelectric modules, each of which is less than or equal to 100 μm in dimensional thickness and formed with the sputter deposited pairs of the N-type thermoelectric legs and the P-type thermoelectric legs on the flexible substrate, a layer of the each thermoelectric module including the sputter deposited N-type thermoelectric legs and the P-type thermoelectric legs having a dimensional thickness less than or equal to 25 μm; and   rendering the formed thin-film based thermoelectric device flexible based on choices of fabrication processes with respect to layers of the each thermoelectric module including the sputter deposited N-type thermoelectric legs and the P-type thermoelectric legs, the flexibility enabling the formed thin-film based thermoelectric device to be completely wrappable and bendable around a system element from which the formed thin-film based thermoelectric device is configured to derive thermoelectric power.   
     
     
         17 . The method of  claim 16 , comprising utilizing one of: a photomask and a hard mask with patterns corresponding to one of: the N-type thermoelectric legs and the P-type thermoelectric legs to aid the sputter deposition thereof. 
     
     
         18 . The method of  claim 16 , further comprising:
 printing and etching a design pattern of metal onto the flexible substrate to form electrically conductive pads, leads and terminals on the flexible substrate, the formed electrically conductive pads, the leads and the terminals having a dimensional thickness less than or equal to 18 μm;   additionally electrodepositing a seed metal layer comprising at least one of: Cr, Ni and Au directly on top of the formed electrically conductive pads, the leads and the terminals on the flexible substrate following the printing and etching thereof, the seed metal layer having a dimensional thickness less than or equal to 5 μm; and   sputter depositing the N-type thermoelectric legs and the P-type thermoelectric legs directly on top of the electrodeposited seed metal layer.   
     
     
         19 . The method of  claim 18 , further comprising sputter depositing a barrier metal layer comprising one of: Cr, Ni and Au on top of the sputter deposited pairs of the N-type thermoelectric legs and the P-type thermoelectric legs utilizing one of: another photomask and another hard mask to further aid metallization contact therewith, the barrier metal layer having a dimensional thickness less than or equal to 5 μm. 
     
     
         20 . The method of  claim 19 , further comprising depositing conductive interconnects on top of the sputter deposited barrier metal layer utilizing a hard mask to assist selective application thereof, the deposited conductive interconnects having a dimensional thickness less than or equal to 25 μm. 
     
     
         21 . The method of  claim 16 , further comprising encapsulating the each thermoelectric module with an elastomer to render the flexibility thereto, the elastomer encapsulation having a dimensional thickness less than or equal to 15 μm.