Browse Prior Art Database

Electroplating With Pulsed Direct Current

IP.com Disclosure Number: IPCOM000079730D
Original Publication Date: 1973-Aug-01
Included in the Prior Art Database: 2005-Feb-26
Document File: 2 page(s) / 36K

Publishing Venue

IBM

Related People

Barr, ER: AUTHOR [+3]

Abstract

Electrodeposited miniature circuit components can be unacceptable for some uses if they are not uniform in thickness, flat in contour and/or free of internal stress. Miniature circuit components which exhibit thickness uniformity, uniform contour and low stress are provided by electroplating, using pulsed direct current.

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Electroplating With Pulsed Direct Current

Electrodeposited miniature circuit components can be unacceptable for some uses if they are not uniform in thickness, flat in contour and/or free of internal stress. Miniature circuit components which exhibit thickness uniformity, uniform contour and low stress are provided by electroplating, using pulsed direct current.

Fig. 1A shows a representative pulsed current form, and Fig. 1B shows the thickness and contour of a series of elements simultaneously deposited from a common bath, on a common substrate using the current of Fig. 1A. Fig. 2A shows a prior art direct current form, while Fig. 2B shows the nonuniform thickness and contour of a series of elements simultaneously deposited from a common bath, on a common substrate using the current of Fig. 2A. For reference, the plating thickness in Fig. 1B is approximately 200 microinches, while the scale in Fig. 2B is approximately the same as that of Fig. 1B. The improvement of thickness and contour uniformity in the deposits of Fig. 1B over those in Fig. 2B, is due to the use of pulsed direct current.

This technique effectively provides superior thickness and contour uniformity in a plating thickness range, of at least about 100 to about 500 microinches. Separation between adjacent conductors may be as little as 200 microinches. The duty cycle of the pulsed current is in the range of about 40-60%, with a 50% duty cycle preferred. A pulse rate of as little as 5-10 cycles per...