Browse Prior Art Database

Prevention of Insulator Breakdown due to Metal Migration

IP.com Disclosure Number: IPCOM000093457D
Original Publication Date: 1967-Sep-01
Included in the Prior Art Database: 2005-Mar-06
Document File: 1 page(s) / 11K

Publishing Venue

IBM

Related People

Kaiser, HD: AUTHOR [+2]

Abstract

High-temperature heat treatment of borosilicate glass insulators prevents breakdown due to metal migration.

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Prevention of Insulator Breakdown due to Metal Migration

High-temperature heat treatment of borosilicate glass insulators prevents breakdown due to metal migration.

In many microelectronic structures a glass is deposited between a pair of metal conductors and then fired to form a solid insulating medium between them. Certain metals, especially silver, show a strong tendency to diffuse into the glass during firing. Then either under high humidity or intense electric field conditions or both, the generally positive metal ions migrate from the more positive, anodic conductor towards the cathodic or less positive conductor. As metal, or in some cases, conducting metal compounds, accumulate at the cathode, the deposit formed grows, reducing effective gap width. Such leads to decreased insulation resistance, increased leakage current, and increased rate of migration. The process continues until the gap is sufficiently narrowed leading to melting or burning of the insulator or complete dielectric breakdown.

However, where a borosilicate glass such as Corning 7052 glass, manufactured by Corning Class Works, is used as the insulating medium, no breakdown occurs when firing is above 850 degrees C. This is attributable to the fact that, at low temperatures, the silver is present in an elemental conductive state. When fired at the higher temperatures, the silver goes into solution with the glass thus rendering the silver nonconductive.

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