Browse Prior Art Database

Nodule Removal Tool

IP.com Disclosure Number: IPCOM000086415D
Original Publication Date: 1976-Sep-01
Included in the Prior Art Database: 2005-Mar-03
Document File: 2 page(s) / 43K

Publishing Venue

IBM

Related People

Skobern, JR: AUTHOR

Abstract

In many electronic packaging systems, the package requires the evaporation of metal layers separated by an insulation layer on a suitable substrate. Often the evaporated metal layer contains small nodules that protrude from the planar surface, which nodules, if of sufficient height, can penetrate the insulative dielectric layer that would normally separate and isolate the metallized surfaces. This causes electrical shorting between the layers.

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Nodule Removal Tool

In many electronic packaging systems, the package requires the evaporation of metal layers separated by an insulation layer on a suitable substrate. Often the evaporated metal layer contains small nodules that protrude from the planar surface, which nodules, if of sufficient height, can penetrate the insulative dielectric layer that would normally separate and isolate the metallized surfaces. This causes electrical shorting between the layers.

A technique for removing these nodules from the planar surface utilizes the system shown in Fig. 1. The substrate 11 has the metallized surface 13 deposited thereon. A commoning ring 15 is placed over the metallized surface 13 and in contact therewith, and the commoning ring 15 is connected to the ground terminal of a power supply 17. A metal plate 19 is connected to the voltage terminal of the power supply 17. The metal plate 19 is adapted to be placed in contact with the nodule on the metallized surface, as shown in Fig. 2. The nodule 21 thus accumulates a high-charge density when voltage is applied by the power supply. Also, there is a very high current density through the nodule, since it is the only conduction point between the plate 19 and the metallized surface 13. This results in a vaporization of the small nodule as shown in Fig. 3, where a depression 23 exists in the surface of the metallized surface 13 where the nodule 21 previously existed.

Once the nodule 21 is removed, the vaporization ceas...