Thick Film Layers and Methods relating thereto

Abstract

Thick film layers for a micro-fluid ejection head, micro-fluid ejection heads, and methods for making micro-fluid ejection head and thick film layers. One such thick film layer is derived from a difunctional epoxy component having a weight average molecular weight ranging from about 2500 to about 4000 Daltons, a photoacid generator, an aryl ketone solvent, and an adhesion enhancing component. One such thick film layer has a cross-link density upon curing that increases the dimensional stability of the thick film layer sufficient to provide flow features therein having substantially vertical walls.

1 - 12 . (canceled) 
   
   
       13 . A method for increasing the planarity of a surface of a thick film layer after photoimaging and developing flow features therein for a micro-fluid ejection head, the method comprising:
 applying a negative photoresist layer adjacent a device surface of a substrate, wherein the negative photoresist layer is derived from a multi-functional epoxy compound, a difunctional epoxy compound, a photoacid generator devoid of aryl sulfonium salts, an adhesion enhancer, and an aryl ketone solvent;   imaging flow features in the photoresist layer; and   developing the imaged photoresist layer to provide the plurality of flow features therein and the substantially planar thick film layer surface.   
   
   
       14 . The method of  claim 13 , wherein the photoacid generator comprises a diaryliodonium hexafluoroantimonate. 
   
   
       15 . The method of  claim 13 , wherein the negative photoresist layer includes substantially equal parts of the multi-functional epoxy compound and the difunctional epoxy compound. 
   
   
       16 . The method of  claim 13 , wherein photoresist layer is applied to the substrate by spin coating the photoresist layer onto the substrate. 
   
   
       17 . The method of  claim 13 , wherein the adhesion enhancer comprises gamma-glycidoxypropyltrimethoxysilane. 
   
   
       18 - 20 . (canceled)