Hewlett-packard Company

Kevin Venor

Joseph Pernyeszi

Michael D Walters

An opaque shield is provided for integrated circuits and comprises reflective particles of titanium dioxide and light-absorbing particles of carbon black suspended in polyimide. The reflective particles increase the effective path length of light traversing the carrier so that a much lower concentration of carbon black is required to render the shield opaque. The concentration of carbon black can be low enough so that its conductivity does not impair operation of the integrated circuit. In addition to shielding the integrated circuit from light, the shield also protects the integrated circuit from contamination. A fluid precursor material is formed by mixing titanium dioxide and carbon black particles into a polyamic acid solution. This solution is diluted, filtered and vacuum distilled to yield a suspension free of over-sized particles. The resulting suspension can be applied and patterned using conventional semiconductor processing techniques. As a result, an integrated circuit can be completely or selectively shielded as desired.

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Ft. Collins, CO, United States of America

Kevin Venor