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Method for Controlling Polyimide/Metal Interfacial Zone for Chemical And Structural Integrity

IP.com Disclosure Number: IPCOM000041170D
Original Publication Date: 1987-Nov-01
Included in the Prior Art Database: 2005-Feb-02
Document File: 1 page(s) / 11K

Publishing Venue

IBM

Related People

Anschel, M: AUTHOR [+3]

Abstract

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.

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Method for Controlling Polyimide/Metal Interfacial Zone for Chemical And Structural Integrity

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. Controlling the PI/Cu interfacial zone for chemical and structural integrity can be accomplished in the following chemical leveling procedure.

Substrates are immersed in sodium or potassium hydroxide solution (N20%) for thirty seconds to one minute followed by two DI water rinses. This immersion is performed immediately prior to the Bright Dip solution step and M-2 evaporation

The controlled formation of interfacial carboxylic in polyamic acid form is seen below.

Disclosed anonymously.

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