Dismiss
InnovationQ will be updated on Sunday, Oct. 22, from 10am ET - noon. You may experience brief service interruptions during that time.
Browse Prior Art Database

Encapsulating Hybrid Circuits

IP.com Disclosure Number: IPCOM000094984D
Original Publication Date: 1965-Aug-01
Included in the Prior Art Database: 2005-Mar-06
Document File: 1 page(s) / 12K

Publishing Venue

IBM

Related People

Kaper, RG: AUTHOR [+2]

Abstract

The encapsulation method is for applying and confining a dielectric gel to the flat surface of a substrate, having no confinement structure on the edges, and curing the gel.

This text was extracted from a PDF file.
This is the abbreviated version, containing approximately 88% of the total text.

Page 1 of 1

Encapsulating Hybrid Circuits

The encapsulation method is for applying and confining a dielectric gel to the flat surface of a substrate, having no confinement structure on the edges, and curing the gel.

The encapsulation method provides preheating the substrate to a temperature of approximately 150 degrees C., +/-25 degrees C. Subsequently, the required amount of dielectric silicon gel and catalyst are applied directly to the top surface of the substrate. A typical commercially available dielectric silicon gel, sold under the trademark SYLGARD* No. 51, has a viscosity at 25 degrees C. of 600 centistokes when uncured. In practice, the gel is normally combined with a suitable catalyst and heated to effect curing. Heat from the substrate is transferred to the gel which causes the curing reaction to immediately begin. This causes the viscosity to increase as the gel rolls out toward the edges of the substrate.

With a substrate measuring .456 x .456 inches, 0.04 gram of a mixture of silicon gel and catalyst is applied centrally to the heated substrate. With the substrate heated to 150 degrees C., the viscosity of the mixture changes upon application to allow the formation of a coating. This extends to the edges and all four corners but does not form over the edges. The resultant coating, excluding the peripheral edges, has an average thickness of 35 mils and varies generally by only +/-5 mils. The coating provides excellent protection for electrical components mounte...