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Metal Foil Preparative Method

IP.com Disclosure Number: IPCOM000049858D
Original Publication Date: 1982-Aug-01
Included in the Prior Art Database: 2005-Feb-09
Document File: 2 page(s) / 20K

Publishing Venue

IBM

Related People

Block, ML: AUTHOR [+2]

Abstract

The use of very thin foils (e.g., less than 1000 Angstroms) is increasing. However, there is no completely satisfactory technique for forming large size thin films of uniform thickness. One typical use for thin films is in masks for X-ray lithography which requires thin films, in some instances only 500 Angstroms thick.

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Metal Foil Preparative Method

The use of very thin foils (e.g., less than 1000 Angstroms) is increasing. However, there is no completely satisfactory technique for forming large size thin films of uniform thickness. One typical use for thin films is in masks for X-ray lithography which requires thin films, in some instances only 500 Angstroms thick.

Accordingly, a technique utilizing selective etching of one layer from a composite material is disclosed. Basically, a very thin layer of the desired end material is applied, such as by electroplating, onto a thicker base layer, and then the thicker base layer is removed, e.g., by electrochemical etching, leaving a thin film of the desired material.

One example of the use of this technique is to form a very thin foil of chromium. A very satisfactory technique starts with a thick ceramic material as a base, shown in the figure, on which is deposited a thin layer of chromium (about 1,000 Angstroms) which is an adhesion promoter. On top of the chromium layer is deposited a relatively thick layer of copper (about 10,000 Angstroms to 20,000 Angstroms). On top of the copper another layer of chromium is deposited, this top layer being of the desired foil thickness. This structure is shown in the figure. This top layer of chromium will be very thin and very uniform and can be of the order of about 500 Angstroms. The ceramic with the chromium layer deposited acts as a sturdy bace, and the copper can be readily dissolved select...