Method of patterning resist for printed wiring board

A process for patterning a photoprocessable layer for a substrate, comprising

• preparing a digital representation of a desired pattern,
• laminating together a layer of photoprocessable material sensitive to directed energy in a first spectrum with a layer of unexposed, undeveloped photographic imaging film sensitive to directed energy in a second spectrum to form a composite,
• applying said composite with the film layer on top to a substrate,
• selectively exposing said film layer with an automatic photoplotter controlled by said digital representation emitting a low energy beam of radiation of substantially longer wavelength than UV so that the film is activated without affecting the underlying layer of photoprocessable material,
• developing the film on the substrate,
• exposing the photoprocessable layer to energy in said first spectrum distributed substantially uniformly over the substrate through the image developed in said film layer as an in situ mask,
• peeling said film off of said substrate, and
• processing said photoprocessable layer,
• whereby low energy plotting can be used to create high resolution inspectable onboard masks.

A method of making a printed wiring board, comprising

• designing a conductor pattern using a CAD system which generates a corresponding digital representation,
• preparing a multilayer composite including an electrically nonconductive substrate covered by an upper layer of photoprocessable material sensitive to high energy UV radiation but insensitive to low energy radiation of substantially longer wavelength than UV, with at least a partial layer of electrically conductive metal between said substrate and said photoprocessable layer,
• laminating a peelable, unexposed, undeveloped photographic imaging strip base film sensitive to low energy radiation of substantially longer wavelength than UV over the photoprocessable layer,
• selectively exposing said film on the substrate with an automatic photoplotter controlled by said digital representation emitting a low energy beam of radiation of substantially longer wavelength than UV so that the film is activated without affecting the underlying layer of photoprocessable material,
• developing the film on the substrate,
• exposing the photoprocessable layer to high energy UV radiation distributed substantially uniformly over the substrate through the image developed in said film as an in situ mask,
• peeling the film off of said substrate, and
• processing said photoprocessable layer by removing portions corresponding to said conductor pattern to define openings therein exposing corresponding portions of said conductive metal layer on said substrate.

A method of making a printed wiring board, comprising

• designing a conductor pattern using a CAD system which generates a corresponding digital representation,
• forming a multilayer composite including a layer of photoprocessable material sensitive to high energy UV radiation but insensitive to low energy radiation of substantially longer wavelength than UV and an adjacent layer of peelable, unexposed, undeveloped photographic imaging strip base film sensitive to low energy radiation of substantially longer wavelength than UV,
• laminating said composite with the film on top to the surface of an electrically nonconductive substrate, with at least a partial layer of electrically conductive metal between said substrate and said photoprocessable layer,
• selectively exposing said film layer with an automatic photoplotter controlled by said digital representation emitting a low energy beam of radiation of substantially longer wavelength than UV so that the film is activated without affecting the underlying layer of photoprocessable material,
• developing the film on the substrate,
• exposing the photoprocessable layer to high energy UV radiation in said first spectrum distributed substantially uniformly over the substrate through the image developed in said film as an in situ mask,
• peeling said film off of said substrate, and
• processing said photoprocessable layer to selectively remove portions corresponding to said conductor pattern to define openings in said photoprocessable layer which expose corresponding portions of the underlying metal layer on said substrate.

A method of making a printed wiring board, comprising

• designing a conductor pattern using a CAD system which generates a corresponding digital representation,
• preparing a multilayer composite including an electrically conductive metal clad nonconductive substrate covered by a UV polymerizable resist layer substantially insensitive to low energy radiation of substantially longer wavelength than UV, covered by a peelable, strip base, unexposed, undeveloped photographic film sensitive to low energy radiation of substantially longer wavelength than UV,
• selectively exposing said film on said composite with an automatic photoplotter controlled by said digital representation emitting a low energy beam of radiation of substantially longer wavelength than UV so that the film is activated without affecting the underlying UV resist layer,
• developing the film on the substrate,
• exposing the UV resist layer to a high energy UV flood lamp through the image developed in said film as an in situ mask to polymerize corresponding portions of said UV resist layer,
• peeling said film off of said substrate,
• removing the unpolymerized portions of said resist layer to define openings through said resist layer exposing corresponding portions of said metal cladding on said substrate,
• removing the exposed metal cladding, and
• removing the remaining polymerized portions of said resist layer to expose the desired conductor pattern.

A method of making a printed wiring board, comprising

• designing a conductor pattern using a CAD system which generates a corresponding digital representation,
• preparing a multilayer composite including an electrically conductive metal foil clad nonconductive substrate covered by a UV sensitive resist layer covered by a peelable, unexposed, undeveloped photographic imaging, strip base film sensitive to low energy radiation of substantially longer wavelength than UV,
• selectively exposing said film on said composite with an automatic photoplotter controlled by said digital representation emitting a low power beam of radiation of substantially longer wavelength than UV so that the film is activated without affecting the underlying UV resist layer,
• developing the film on the substrate,
• exposing the UV resist layer to a UV flood lamp through the image developed in the film to polymerized corresponding portions of said UV resist,
• peeling said film off of said substrate,
• removing the unpolymerized portions of said resist layer to define openings therethrough to expose corresponding portions of said foil cladding,
• electroplating metal onto said exposed portions of said metal cladding thereby substantially filling the openings in said resist layer,
• removing the remaining polymerized portions of said resist layer, and
• removing the remainder of the exposed foil cladding thus leaving the plated conductor pattern.

A method of making a printed wiring board, comprising

• designing a conductor pattern using a CAD system which generates a corresponding digital representation,
• preparing a multilayer composite including an electrically nonconductive substrate under a patterned electrically conductive foil layer corresponding to said conductor pattern, covered by a UV sensitive photoprocessable layer, covered in turn by a peelable, unexposed, undeveloped photographic imaging, strip base film sensitive to low energy radiation of substantially longer wavelength than UV,
• selectively exposing said film on said composite with an automatic photoplotter controlled by said digital representation emitting a low energy beam of radiation of substantially longer wavelength than UV so that the film is activated without affecting the underlying layer of photoprocessable material,
• developing the film on the substrate,
• exposing the photoprocessable layer to a UV flood lamp through the image developed in said film as an in situ mask to polmerize corresponding portions of said photoprocessable layer,
• peeling said film off of said substrate,
• removing the unpolymerized portions of said photoprocessable layer to define channels therein exposing said patterned foil, and
• filling said channels with metal to complete said conductor pattern.

A method of making a printed wiring board, comprising

• designing a conductor pattern using a CAD system which generates a corresponding digital representation,
• preparing a multilayer composite including an electrically nonconductive substrate under a conductor pattern of electrically conductive metal covered with a UV sensitive permanent dry film layer covered by a peelable, unexposed, undeveloped photographic imaging strip base film sensitive to radiation of substantially longer wavelength than UV,
• selectively exposing said photographic film on said composite with an automatic photoplotter controlled by said digital representation emitting a low energy beam of radiation of substantially longer wavelength than UV so that the photographic film is activated without affecting the underlying layer of permanent dry film,
• developing the photographic film on the substrate,
• exposing the permanent dry film layer to a UV flood lamp through the image developed in said photographic film as an in situ mask to polymerized corresponding portions of said permanent dry film,
• peeling said photographic film off of said substrate,
• removing the unpolymerized portions of said permanent dry film to define openings therethrough exposing corresponding portions of said conductor pattern,
• whereby electrical connections can be made to said conductor pattern through the openings in said permanent dry film.