Method for making flexible circuits
AssigneeMinnesota Mining and Manufacturing Company
InventorsThomas P. Klun, Thach G. Truong
Life of this patent
Estimating the term…
Abstract
A process for making flexible circuits wherein the etching of a polymeric film is accomplished by dissolving portions thereof with concentrated aqueous base using an aqueous processible crosslinked photoresist as a mask, comprising the steps of laminating the resist on a polymeric film, exposing a pattern into the resist, developing the resist with a dilute aqueous solution until desired image is obtained, etching portions of the polymeric film not covered by the crosslinked resist with a concentrated base at a temperature of from about 50.degree. C. to about 120.degree. C., and then stripping the resist off the polymeric film.
Claims16
A process for etching a fully cured or substantially fully cured polymeric film which comprises contacting said polymeric film with a concentrated base at a temperature of from about 50.degree. C. to about 120.degree. C., wherein portions of said polymeric film are protected with a mask comprising a crosslinked negative aqueous processible photoresist, said photoresist exhibiting substantially no swelling or delamination from said polymeric film during said etching.
A process for making a flexible printed circuit wherein etching of a polymeric film is accomplished by dissolving portions thereof with concentrated aqueous base, using a crosslinked negative aqueous processible photoresist as a mask, comprising the steps of
- a) laminating said resist on a flexible substrate comprising a layer of polymeric film and a thin layer of copper,
- b) exposing at least a portion of said resist thereby crosslinking said exposed portions,
- c) developing said resist with a dilute aqueous solution until desired patterns are obtained,
- d) plating circuitry atop said thin copper layer to desired thickness,
- e) etching portions of said polymeric film not covered by the crosslinked resist with a concentrated base at a temperature of from about 70.degree. C. to about 120.degree. C.,
- f) stripping said resist off said polymeric film with dilute basic solution, and
- g) etching said thin copper layer to obtain circuitry.
A process for making a flexible circuit wherein etching of a polymeric film is accomplished by dissolving portions thereof with concentrated aqueous base using a crosslinked negative aqueous processible photoresist as a mask, comprising the steps of
- a) laminating said resist at a flexible substrate which consists of a layer of polymeric film and a thick layer of copper,
- b) exposing at least a portion of said resist thereby crosslinking said exposed portions thereof,
- c) developing said resist with a dilute aqueous solution until desired patterns are obtained,
- d) etching said thick copper layer to obtain circuitry, thus exposing areas of said polymeric film,
- e) laminating an additional layer of photoresist over said copper layer, and flood exposing said resist, to crosslink said resist in order to protect exposed areas of polymeric film from etching,
- f) etching portions of said polymeric film not covered by the crosslinked resist with a concentrated base at a temperature of from about 70.degree. C. to about 120.degree. C., and
- g) stripping said resist with dilute basic solution.
Dependencies are inferred from the claim text.