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Automated Process for Testing the Airtightness of Encapsulated Modules

IP.com Disclosure Number: IPCOM000062500D
Original Publication Date: 1986-Dec-01
Included in the Prior Art Database: 2005-Mar-09
Document File: 2 page(s) / 40K

Publishing Venue

IBM

Related People

Michon, S: AUTHOR [+2]

Abstract

The conventional processes currently used for testing the airtightness of small sealed elements, such as the covers of encapsulated modules, generally call for two successive operations to reveal the possible presence of so-called fine leaks and gross leaks. The fine leaks are revealed by using mass spectography techniques during a first operation, whereas the gross leaks are revealed during a subsequent operation by immersing the module into a fluorocarbon bath and checking for any air bubbles emanating from the module cover. Such conventional operations are time consuming and, furthermore, make it impractical to automatize the test. The present process calls for holographic interferometry for testing the airtightness of the covers of encapsulated modules.

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Automated Process for Testing the Airtightness of Encapsulated Modules

The conventional processes currently used for testing the airtightness of small sealed elements, such as the covers of encapsulated modules, generally call for two successive operations to reveal the possible presence of so-called fine leaks and gross leaks. The fine leaks are revealed by using mass spectography techniques during a first operation, whereas the gross leaks are revealed during a subsequent operation by immersing the module into a fluorocarbon bath and checking for any air bubbles emanating from the module cover. Such conventional operations are time consuming and, furthermore, make it impractical to automatize the test. The present process calls for holographic interferometry for testing the airtightness of the covers of encapsulated modules. By using holographic interferometry, it becomes possible to check during a single operation whether fine or gross leaks are present and, furthermore, it becomes possible to automatize the test. The module, whose airtightness is to be tested, is transported by a conveyor 1 into a sealed chamber 2, wherein, with the chamber at atmospheric pressure, a first holographic picture of the module, generated by the beams of a laser 3 impinging upon the module, is recorded on the film of a holographic camera 4 associated with the chamber. Then, a negative pressure is applied to the chamber and, after a predetermined time delay, a second holographic pi...