Method for Controlling Polyimide/Metal Interfacial Zone for Chemical And Structural Integrity
Original Publication Date: 1987-Nov-01
Included in the Prior Art Database: 2005-Feb-02
In the manufacture of substrates using metallization on polyimide the formation of an interfacial carboxylic functionality zone is of prime importance for polyimide (PI) adhesion to metallization with good bond formation to prevent line lifting. Poor metal line adhesion is caused by uncontrolled oxidation during prior processing steps of PI, i.e., 1) alkaline potassium permanganate (chromium etchant), 2) ferric chloride (copper etchant), 3) oxygen asher (removes organic contamination in via) and 4) bright dip solution (oxide removal from copper in via). These four processing steps lead to some carboxylic acid functional group formation in PI but in an uncontrolled manner and by-product fashion because they are intended for other purposes.