The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Feb. 21, 1989
Filed:
May. 01, 1987
Thomas E Kazior, Sudbury, MA (US);
Mark S Durschlag, Natick, MA (US);
Raytheon Company, Lexington, MA (US);
Abstract
A method of simultaneously forming recesses for via holes and tub structures in a substrate is provided in a common etching step by defining a mask pattern for the via hole as a single aperture and by defining a mask pattern for the tub structure as a plurality of thin slots. The slots are chosen to have a smaller cross-sectional dimension than the corresponding dimension for the single aperture. Etchant brought into contact with the substrate will etch the substrate at a slower rate in the slots than in the single apertur such that the via hole will etch completely through the substrate whereas, the tub structure will be etched only partially through the substrate. Conductive material is provided in the tub structure and via hole, and a layer of conductive material is disposed thereover, to provide a heat sink/ ground plane conductor. Electrical contact is provided between the frontside of the substrate and the heat sink/ground plane conductor through the via hole, whereas a low thermal impedance path is provided through the tube structure between a heat dissipating element supported on the frontside of the substrate and the heat sink/ground plane conductor.