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Browse Prior Art Database

Fabricating Small Interconnection Structures

IP.com Disclosure Number: IPCOM000079764D
Original Publication Date: 1973-Sep-01
Included in the Prior Art Database: 2005-Feb-26
Document File: 2 page(s) / 37K

Publishing Venue

IBM

Related People

Juras, AJ: AUTHOR [+3]

Abstract

Patterns of via holes and grooves are cut into an organic plating mask material by thermal electron-beam machining. By subsequent plating, an interconnection structure is obtained for multilayer module fabrication.

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Fabricating Small Interconnection Structures

Patterns of via holes and grooves are cut into an organic plating mask material by thermal electron-beam machining. By subsequent plating, an interconnection structure is obtained for multilayer module fabrication.

A plating mask is formed; by metal deposition and photolithographic processes, a continuous chromium electrode film 1 (plating electrode) with copper/chromium/copper pad 2 is obtained on a glass layer 7. On this substrate, a 1/2 mil primer 3 is sprayed and a 3 mil polymethyl methacrylate layer 4 is laminated to it. This composite organic ensures good adhesion and ease of removal while being an effective plating mask. Other plating mask materials may be useful. However, a photosensitive property in the mask material is not required.

An electric contact 5 is made with the electrode 1 for monitoring the E-beam Cutting process by a beam sense (BS) signal. As the beam removes the organic, more beam electrons are stopped in the pad 2, causing the BS signal to rise until it corresponds to the full-beam current at the completion of the via hole. Then, by feedback, the BS signal turns the E-beam off. Should the E-beam miss the pad, most of the 75 KeV electrons will pass through the thin chromium electrode and the BS signal amplitude will be less.

The BS signal is used for: (1) Beam-off trigger which compensates for organic thickness variations, (2) "Via hole complete" test, and (3) "Via hole on pad" test.

An example...