Browse Prior Art Database

Control for Monitoring Etching

IP.com Disclosure Number: IPCOM000092829D
Original Publication Date: 1967-Mar-01
Included in the Prior Art Database: 2005-Mar-05
Document File: 2 page(s) / 62K

Publishing Venue

IBM

Related People

Tatusko, PA: AUTHOR

Abstract

In the manufacture of circuit tapes in a continuous web, an acid resisting image is printed on the copper side of the web. Acid is then sprayed on the copper and the unwanted copper is dissolved away. Three webs are etched at one time. One important specification of a circuit tape is line width which is critical as far as capacitance and noise are concerned.

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Control for Monitoring Etching

In the manufacture of circuit tapes in a continuous web, an acid resisting image is printed on the copper side of the web. Acid is then sprayed on the copper and the unwanted copper is dissolved away. Three webs are etched at one time. One important specification of a circuit tape is line width which is critical as far as capacitance and noise are concerned.

Three control patches are printed by the same setup as the acid resist image. The control patch consists of dots of different diameters such as 2, 4, 6 and 8 mils. Since it is desired to control line width, the etching operator can observe the side etching of the dots. If the printed pattern is too wide, the etching cycle can be controlled so that the .006" or .008" dots etch away. If the pattern is light, only the .002" or .004" dots are allowed to etch away. Therefore, the dot pattern can serve as an indicator to control etching over all webs so that a more uniform line width can be maintained.

The printing of control dots on the workpiece being etched to monitor the etching has the advantage that any variance in printing of the image to be etched is the same in the dots. This is because they are printed at the same time. Hence, a uniform control can be maintained even though the printing varies for different runs of tapes.

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