System and process for detecting leaks in sealed articles
First Claim
1. A method of leak testing a hermetic electronic package of the type that has an internal chamber that is isolated from ambient conditions by a seal structure, comprising steps of:
- stimulating the hermetic electronic package with a non-linear modulated input of energy;
sensing a property of the hermetic electronic package that changes as a first function of the modulated input of energy and a second function of pressure conditions within said hermetically sealed internal chamber, said first and second functions being linearly independent; and
determining a leak rate of the hermetic electronic package based on the known modulated input of energy and the sensed property, said determination being performed in reliance on the linear independence of said first and second functions in such a manner that it is substantially independent of structural manufacturing variances of the hermetic electronic package that are unrelated to the integrity of the seal.
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Accused Products
Abstract
A system and method for leak testing a plurality of hermetic electronic packages of the type that have an internal chamber that is isolated from ambient conditions by a seal structure is advantageously designed to be able to calculate the leak rate of each individual device in a manner that is independent of structural manufacturing variances that typically exist within a sampling of such devices. The method preferably involves positioning a plurality of the hermetic electronic packages within a test area, and then stimulating the hermetic electronic packages with a modulated input of energy, such as by varying the ambient pressure about the devices. A property such as the physical position of one portion of a lid of each of the hermetic electronic packages is then sensed. The sensed property is one that is known to change as a first function of the modulated input of energy and also as a second function of pressure conditions within the hermetically sealed internal chamber. The first and second functions are linearly independent of each other. By comparing the stimulation of the devices to the sensed property and by discriminating using the two known functions a leak rate is determined for each individual device that is substantially independent of variances, such as differences in lid thickness that may exist between the different devices. Accordingly, an accurate determination of leak rate may be made with a minimum of calibration.
36 Citations
53 Claims
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1. A method of leak testing a hermetic electronic package of the type that has an internal chamber that is isolated from ambient conditions by a seal structure, comprising steps of:
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stimulating the hermetic electronic package with a non-linear modulated input of energy;
sensing a property of the hermetic electronic package that changes as a first function of the modulated input of energy and a second function of pressure conditions within said hermetically sealed internal chamber, said first and second functions being linearly independent; and
determining a leak rate of the hermetic electronic package based on the known modulated input of energy and the sensed property, said determination being performed in reliance on the linear independence of said first and second functions in such a manner that it is substantially independent of structural manufacturing variances of the hermetic electronic package that are unrelated to the integrity of the seal. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12)
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13. A method of leak testing a plurality of hermetic electronic packages of the type that have an internal chamber that is isolated from ambient conditions by a seal structure, comprising steps of:
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positioning a plurality of hermetic electronic packages within a test area;
stimulating the hermetic electronic packages with a non-linear modulated input of energy;
sensing a property of each of the hermetic electronic packages that changes as a first function of the modulated input of energy and a second function of pressure conditions within said hermetically sealed internal chamber, said first and second functions being linearly independent; and
determining a leak rate of each hermetic electronic package based on the known modulated input of energy and the sensed property, said determination being performed in reliance on the linear independence of said first and second functions in such a manner that it is substantially independent of structural manufacturing variances between the individual hermetic electronic packages that are unrelated to the integrity of the seal. - View Dependent Claims (14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24)
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25. An apparatus for leak testing a hermetic electronic package of the type that has an internal chamber that is isolated from ambient conditions air by a seal structure, comprising:
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energy input means for stimulating the hermetic electronic package with a non-linear modulated input of energy;
sensing means for sensing a property of the hermetic electronic package that changes as a first function of the modulated input of energy and a second function of pressure conditions within said hermetically sealed internal chamber, said first and second functions being linearly independent; and
determining means for determining a leak rate of the hermetic electronic package based on the known modulated input of energy and the sensed property, said determining means being constructed and arranged to make such a determination in reliance on the linear independence of said first and second functions in such a manner that it is substantially independent of structural manufacturing variances of the hermetic electronic package that are unrelated to the integrity of the seal. - View Dependent Claims (26, 27, 28, 29, 30, 31, 32, 33)
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34. An apparatus for leak testing a plurality of hermetic electronic packages of the type that have an internal chamber that is isolated from ambient conditions air by a seal structure, comprising:
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positioning means for positioning a plurality of hermetic electronic packages within a test area;
energy input means for stimulating the hermetic electronic packages with a non-linear modulated input of energy;
sensing means for sensing a property of each of the hermetic electronic packages that changes as a first function of the modulated input of energy and a second function of pressure conditions within said hermetically sealed internal chamber, said first and second functions being linearly independent; and
determining means for determining a leak rate of each hermetic electronic package based on the known modulated input of energy and the sensed property, said determination being performed in reliance on the linear independence of said first and second functions in such a manner that it is substantially independent of structural manufacturing variances between the individual hermetic electronic package that are unrelated to the integrity of the seal. - View Dependent Claims (35, 36, 37, 38, 39, 40, 41, 42)
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43. A method of leak testing a sealed article of the type that has an internal chamber that is isolated from ambient conditions by a seal structure, comprising steps of:
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stimulating the sealed article with a non-linear modulated input of energy;
sensing a property of the sealed article that changes as a first function of the modulated input of energy and a second function of pressure conditions within said sealed article, said first and second functions being linearly independent; and
determining a leak rate of the sealed article based on the known modulated input of energy and the sensed property, said determination being performed in reliance on the linear independence of said first and second functions in such a manner that it is substantially independent of structural manufacturing variances of the sealed article that are unrelated to the integrity of the seal. - View Dependent Claims (44, 45, 46, 47, 48, 49, 50, 51, 52, 53)
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Specification