Measurements of dimensional and electrical characteristics of printed boards made with IPC Multi-Purpose Test Pattern, B-25
Printed boards fabricated at four suppliers with Multi-Purpose Test Pattern B-25 are compared. Two suppliers used panel plating and two pattern plating in board fabrication. Bare as well as solder mask coated boards are compared. Average deviations of conductor widths from design widths ranged from -0.010 to -0.038 mm on phototools and -0.061 to 0.041 mm on boards. The deviations depended mainly on fabrication period and source. Copper thicknesses obtained from resistance measurements, ranging from 0.056 to 0.079 mm, were within 5 percent of those obtained from beta backscatter and cross section measurements. Breakdown voltages between conductor separations of 0.08 to 0.76 mm were roughly 70 percent of those for the Paschen curve for air in a quasi uniform electric field (spherical electrodes). Mean breakdown voltage V/sub BD/ in kV for conductor separation S in mm is expressed by the relationship, V/sub DB/ = 3.1 S/sup 0/./sup 63/, regardless of board source. Boards with solder mask coatings are approximately 40 percent higher in breakdown voltage. No breakdowns occurred at less than 500 volts under normal atmospheric conditions. The influence of close spacing of adjacent current carrying conductors on the current carrying capability of a conductor is shown to be appreciable for this conductor test pattern.
- Research Organization:
- Sandia Labs., Albuquerque, N.Mex. (USA)
- DOE Contract Number:
- EY-76-C-04-0789
- OSTI ID:
- 7076528
- Report Number(s):
- SAND-77-1837C; CONF-780604-1
- Resource Relation:
- Conference: 1. printed circuit world convention, London, UK, 5 Jun 1978; Other Information: Portions of document are illegible
- Country of Publication:
- United States
- Language:
- English
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