Hermetic seal and controlled impedance RF connections for a liquid metal micro switch
First Claim
1. An electronic assembly comprising:
- a substrate having a first surface;
a layer of dielectric material having first and second surfaces whose shapes generally match that of a mounting footprint of a device to be mounted on the substrate, the first surface of the layer of dielectric material adhering to the first surface of the substrate at a location thereof where the device is to be mounted;
a LIMMS device mounted on the substrate and having a mounting surface adhering to the second surface of the layer of dielectric material; and
a fillet of hermetic sealing material disposed against both a perimeter of the mounting surface of the LIMMS device and a region of the second surface of the dielectric layer proximate the perimeter of the mounting surface of the LIMMS device.
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Accused Products
Abstract
One or more LIMMS devices on a substrate, possibly having same-surface signal conductors, are hermetically sealed by either: (a) Enclosing each entire LIMMS device beneath a common or respective outer cover that is separate from the LIMMS device(s) and impervious to contaminants; or (b) Fabricating each LIMMS device such that its individual cover block (which is already a component of the LIMMS and is not a separate outer cover) can be hermetically sealed against the substrate. Each case must limit the effects of the hermetic seal upon impedances. In case (a) the substrate is covered with a layer of dielectric material matching the ribbon-like footprint of the perimeter of the separate outer cover. In case (b), the entire (solid) footprint of the LIMMS cover block on the substrate receives a layer of dielectric material, which may itself then be covered, save for near its perimeter, with suitable adhesive. In case (a) the outer cover may be soldered to the perimeter footprint. In case (b) the cover block may be soldered to dielectric layer. In another embodiment for cases (a) and (b) glass frit is used in place of solder. Disturbances to signal line impedance may be compensated by changes in signal conductor width. The layer of suitable dielectric material may be a thin sheet or gasket of previously patterned ceramic material, or it may be formed by the application of a thick film paste. Suitable thick film dielectric materials deposited as a paste and subsequently cured include the KQ 150 and KQ 115 thick film dielectrics from Heraeus and the 4141 A/D thick film compositions from DuPont.
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Citations
18 Claims
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1. An electronic assembly comprising:
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a substrate having a first surface;
a layer of dielectric material having first and second surfaces whose shapes generally match that of a mounting footprint of a device to be mounted on the substrate, the first surface of the layer of dielectric material adhering to the first surface of the substrate at a location thereof where the device is to be mounted;
a LIMMS device mounted on the substrate and having a mounting surface adhering to the second surface of the layer of dielectric material; and
a fillet of hermetic sealing material disposed against both a perimeter of the mounting surface of the LIMMS device and a region of the second surface of the dielectric layer proximate the perimeter of the mounting surface of the LIMMS device. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10)
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11. An electronic assembly comprising:
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a substrate having a first surface;
a LIMMS device mounted on the substrate;
an outer cover having a recess therein for enclosing the LIMMS device and also having a mounting perimeter surface;
a ribbon of dielectric material having first and second surfaces whose shapes generally match that of the mounting perimeter surface of the outer cover, the first surface of the ribbon dielectric material adhering to the first surface of the substrate at a location thereof that both surrounds the LIMMS device and that encompasses where the outer cover is to enclose the LIMMS device;
a fillet of hermetic sealing material disposed against both the mounting perimeter surface of the outer cover and a region of the second surface of the ribbon of dielectric material proximate the mounting perimeter surface of the outer cover. - View Dependent Claims (12, 13, 14, 15, 16, 17, 18)
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Specification