Browse Prior Art Database

Module Leak Fixture

IP.com Disclosure Number: IPCOM000046624D
Original Publication Date: 1983-Aug-01
Included in the Prior Art Database: 2005-Feb-07
Document File: 2 page(s) / 58K

Publishing Venue

IBM

Related People

Horvath, J: AUTHOR [+3]

Abstract

A testing fixture is provided for leak testing of hermetically sealed electronic modules. Hermetically sealed electronic modules are required to undergo leak testing by the use of a tracer gas, such as helium. The tracer gas is forced into the module under pressure, and the module is then placed in a helium detector to determine the presence of and the nature of any leak present. With some modules the external porosity of the cooling fins can absorb helium which, during the detection part of the test, gives the appearance of the leak known as the virtual leak. The present apparatus and method eliminate this problem. The module test fixture shown in Fig. 1 avoids testing errors due to the outgassing of the trace gas due to external porosity of the cooling fins.

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Module Leak Fixture

A testing fixture is provided for leak testing of hermetically sealed electronic modules. Hermetically sealed electronic modules are required to undergo leak testing by the use of a tracer gas, such as helium. The tracer gas is forced into the module under pressure, and the module is then placed in a helium detector to determine the presence of and the nature of any leak present. With some modules the external porosity of the cooling fins can absorb helium which, during the detection part of the test, gives the appearance of the leak known as the virtual leak. The present apparatus and method eliminate this problem. The module test fixture shown in Fig. 1 avoids testing errors due to the outgassing of the trace gas due to external porosity of the cooling fins. The test fixture consists of a mounting plate 10 on which module 12 is placed during leak testing.

An 0-ring frame 14 is secured to mounting plate 10 by clamps 16. A frame to plate 0-ring 18 and a frame to cap 0-ring seal 20 hold the vacuum applied to chamber 22. Successful operation of the fixture requires a hermetic seal at the contact surfaces of both 0-rings.

Under these conditions helium emanating from a non-hermetic module seal joint would enter the leak detection chamber 22 and indicate a leak. An alternate technique for avoiding erroneous results resulting from porosity of the cooling fins is shown in Fig. 2. In this fixture the seal joint of module 12 is subjected to helium unde...