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Sacrificial Electrode for Field-Assist Bonding

IP.com Disclosure Number: IPCOM000049044D
Original Publication Date: 1982-Apr-01
Included in the Prior Art Database: 2005-Feb-09
Document File: 2 page(s) / 21K

Publishing Venue

IBM

Related People

Kurth, RH: AUTHOR

Abstract

This method of field-assist bonding with a "sacrificial electrode" eliminates pits and sodium deposits from bonded glass parts.

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Sacrificial Electrode for Field-Assist Bonding

This method of field-assist bonding with a "sacrificial electrode" eliminates pits and sodium deposits from bonded glass parts.

An electrode 10, a battery 12. and another electrode 14 are used in field- assist bonding, for example, for joining material 16, such as silicon, to a glass substrate 18. Were the glass substrate 18 in contact with the electrode 10 (the element 20 absent), sodium would be driven to the surface of the glass substrate 18 where it would contact the electrode 10. When the glass substrate cools after bonding the sodium on the suface, it reacts with air and attracts water vapor and carbon dioxide. This forms sodium hydroxide and sodium carbonate as well as leaving an undesirable pitted surface. For most applications the deposits must be removed from the glass before using in any critical application.

A glass member 20 is therefore interposed between the electrode 10 and the glass substrate 18. This technique drives the sodium to the "sacrificial electrode" which is discarded when the bonding is completed. The cost of fabrication is no greater than that involving removal of the deposits, and the glass substrate is free of pits as well.

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