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Photocell Controlled Etcher

IP.com Disclosure Number: IPCOM000093492D
Original Publication Date: 1967-Oct-01
Included in the Prior Art Database: 2005-Mar-06
Document File: 3 page(s) / 48K

Publishing Venue

IBM

Related People

Greene, KF: AUTHOR [+3]

Abstract

Copper can be etched from the surface of panel 2 having an epoxy glass substrate, on either a batch or continuous basis, by the use of photocell controlled equipment. Advantage is taken of the difference in the reflectance of light from epoxy glass and from copper to detect the removal of copper from the panel surface.

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Photocell Controlled Etcher

Copper can be etched from the surface of panel 2 having an epoxy glass substrate, on either a batch or continuous basis, by the use of photocell controlled equipment. Advantage is taken of the difference in the reflectance of light from epoxy glass and from copper to detect the removal of copper from the panel surface.

The photoelectric system can be one in which light from bulb 1 is reflected from the surface of panel 2 to photocell 3, so that a change in the output of photocell 3, due to the difference in reflectance between copper and epoxy glass, indicates the removal of the copper.

In another system, light from ultraviolet source 4 is reflected off panel 2 towards photocell 3. Ultraviolet filter 5 filters out any reflected ultraviolet light. In such application, copper, both new and partially etched, fluoresces very slightly so as to emit only a dull violet glow. In contrast, the epoxy glass fluoresces more strongly emitting strong white visible light. By blocking the ultraviolet light from the light source and sensing the difference in fluorescence between the copper and epoxy glass, an indication can be obtained from the photocell of the removal of the copper.

In another system, filter 6 is placed in the patch of light from source 1 to project polarized light onto panel 2. A second polarizing filter 7 is placed in front of the photocell. With such a system, the reflection from copper surface is affected by the angle of rotation of filter 7, while the reflection from a glass surface is not affected to the same extent. Thus, filter 7 can be rotated to optimize this difference between the reflectance of polarized light from the glass and copper as to activate or cause photocell 3 to provide an indication when the copper is removed.

In batch processing, panel 2 is oscillated or rotated between sprayers 8 that direct the etchant upon the surfaces to be etched. Photoelectric controllers PC, that include any of the described photo electric systems, are mounted for controlling the flow of etchant from

In batch processing, panel 2 is oscillated or rotated between sprayers 8 that direct the etchant upon the surfaces to be etched. Photoelectric controllers PC, that include any of the described photo electric systems, are mounted for controlling the flow of etchant from sprayers 8, so that, when...