Residual material detection in backdrilled stubs
AssigneeInternational Business Machines Corporation
InventorsGerald K. Bartley, Darryl J. Becker, Matthew S. Doyle, Philip R. Germann, Mark O. Maxson
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Abstract
A stub of a via formed in a printed circuit board is backdrilled to a predetermined depth. A capacitance probe is positioned within the via. Then the capacitance probe is used to obtain a test capacitance measurement. The test capacitance measurement is compared to a predetermined baseline capacitance measurement. Residual conductive plating material in the backdrilled stub causes the test capacitance measurement to exceed the predetermined baseline capacitance measurement. An indication is made that the predetermined baseline capacitance measurement has been exceeded.
Claims10
A method for measuring and assessing the adequacy of a backdrilling operation, the method comprising:
- backdrilling a stub of a via formed in a printed circuit board to a predetermined depth;
- positioning a capacitance probe within the via;
- subsequent to the backdrilling to the predetermined depth and the positioning the capacitance probe, using the capacitance probe to obtain a test capacitance measurement;
- comparing the test capacitance measurement to a predetermined baseline capacitance measurement, residual conductive plating material in the backdrilled stub causing the test capacitance measurement to exceed the predetermined baseline capacitance measurement;
- and
- indicating that the test capacitance measurement exceeds the predetermined baseline capacitance measurement.
Dependencies are inferred from the claim text.