Fine line thick film resistors by photolithography

Abstract

The present invention is directed to a thick film patterned resistor on a substrate and to a method of forming it. The method involves providing a substrate with opposed surfaces, where one surface is coated with a layer of a resistor composition. A photoresist is applied over the layer of the resistor composition, and a desired pattern in the photoresist is formed, where the pattern leaves certain regions of the resistor composition layer uncovered by the photoresist. The resistor composition layer which is uncovered by the photoresist is etched under conditions effective to leave a mass of loosely bound resistor particles at regions of the resistor composition which are not covered by photoresist. The mass of resistor particles is then removed from the substrate to produce a thick film patterned resistor on the substrate.

1 . A thick film patterned resistor produced by the method comprising: 
 providing a substrate with opposed surfaces, wherein one surface is coated with a layer of a resistor composition;    applying a photoresist over the layer of the resistor composition;    forming a desired pattern in the photoresist, wherein the pattern leaves certain regions of the resistor composition layer uncovered by the photoresist;    etching the resistor composition layer which is uncovered by the photoresist under conditions effective to leave a mass of bound resistor particles at regions of the resistor composition layer which are not covered by photoresist; and    removing the mass of unbound resistor particles from the substrate to produce a thick film patterned resistor on the substrate.    
   
   
       2 . The thick film patterned resistor of  claim 1 , wherein the method further comprises removing residual photoresist after said removing the mass of unbound resistor particles from the substrate.  
   
   
       3 . The thick film patterned resistor of  claim 1 , wherein the thick film patterned resistor has resistor lines having a width of 0.0005 to 0.020 inches.  
   
   
       4 . The thick film patterned resistor of  claim 1 , wherein the thick film patterned resistor has resistor lines with a serpentine configuration.  
   
   
       5 . A thick film patterned resistor on a substrate comprising: 
 a substrate and    a resistor composition, comprising a binder and etchant insoluble particles, which has been sintered and then patterned.    
   
   
       6 . The thick film patterned resistor according to  claim 5 , wherein the substrate is selected from the group consisting of alumina, beryllium oxide, aluminum nitride, sapphire, magnesium titanate, barium titanate, neodymium titanate, zirconium tin titanate, zirconia toughened alumina, yttria partially stabilized zirconia, boron nitride, diamond, silicon, and silicon coated with insulating material.  
   
   
       7 . The thick film patterned resistor according to  claim 5 , wherein the binder is selected from the group consisting of aluminum, barium, bismuth trioxide, boroaluminosilicate glass, boron, calcium oxide, copper, fused silica (amorphous), gadolinium, glass frit, lead, lead compounds, leaded glass frit, manganese compounds, potassium, ruthenium, silica (amorphous), sodium, TiO 2 , vanadium, zinc, zirconium, and zirconium silicate.  
   
   
       8 . The thick film patterned resistor according to  claim 5 , wherein the etchant insoluble particles are selected from the group consisting of oxides or oxide compounds of indium, thallium, ruthenium, palladium, tungsten, osmium, iridium, and rhodium as well as gold, silver, platinum, and palladium, either in elemental form or in compounds.  
   
   
       9 . The thick film patterned resistor according to  claim 5 , wherein the layer of the resistor composition has a thickness of 0.0001 to 0.0015 inches.  
   
   
       10 . The thick film patterned resistor according to  claim 5 , wherein the thick film patterned resistor is formed from resistor lines having a width of 0.0001 to 0.0015 inches.  
   
   
       11 . The thick film patterned resistor according to  claim 5 , wherein the thick film patterned resistor has resistor lines with a serpentine configuration.  
   
   
       12 . A thick film patterned resistor on a substrate, wherein the resistor comprises resistor lines having a width of 0.0001 to 0.0015 inches.