Devices including, methods using, and compositions of reflowable getters
Methods for protecting circuit device materials, optoelectronic devices, and caps using a reflowable getter are described. The methods, devices and caps provide advantages because they enable modification of the shape and activity of the getter after sealing of the device. Some embodiments of the invention provide a solid composition comprising a reactive material and a phase changing material. The combination of the reactive material and phase changing material is placed in the cavity of an electronic device. After sealing the device by conventional means (epoxy seal for example), the device is subjected to thermal or electromagnetic energy so that the phase changing material becomes liquid, and consequently: exposes the reactive material to the atmosphere of the cavity, distributes the getter more equally within the cavity, and provides enhanced protection of sensitive parts of the device by flowing onto and covering these parts, with a thin layer of material.
1. A cap comprising a getter, the cap further comprising:
a reactive material disposed on a cap surface; and
an inert material that covers more than approximately fifty percent of the reactive material,
wherein the inert material is adapted to flow in response to application of energy to the inert material,
wherein the cap comprises an interior surface having a recessed portion;
wherein the inert material covers less than the entire recessed portion; and
wherein a cavity is positioned between the inert material and at least one sidewall of the recessed portion.
2. The cap of claim 1 , wherein:
the inert material covers at least some of the recessed portion; and
the inert material is adapted to melt in response to the application of energy.
3. A device, comprising:
a cap comprising a recessed portion; and
a getter comprising an inert material and a reactive material,
wherein the inert material is adapted to respond to energy input by undergoing at least one of a phase change and a morphological change;
wherein the getter is at least partially arranged in the recessed portion; and
wherein the inert material and the reactive material form two separate layers of the getter.
4. The device of claim 3 , wherein the phase change comprises melting.
5. The device of claim 3 , wherein the recessed portion comprises an interior surface, and wherein between 25% and 90% of the interior surface is covered by the reactive material.
6. The device of claim 3 , wherein the recessed portion comprises a pre-reflow cavity which is free of the getter.
7. The device of claim 3 , wherein the reactive material is formed as a layer having a thickness in a range from 0.1 micrometers to 10 micrometers.
8. The device of claim 3 , wherein:
the recessed portion comprises an interior surface;
the inert material completely covers portions of a surface of the reactive material that are not covered by the cap; and
the inert material covers a portion of the interior surface.
9. The device of claim 3 , wherein:
the reactive material comprises particles of a reactive metal or an alkaline metal oxide; and
sizes of the particles are in a range from about 0.1 micrometers to about 200 micrometers.
10. The device of claim 9 , wherein the sizes of the particles are in a range from about 0.3 micrometers to about 50 micrometers.
11. The device of claim 3 , wherein:
the getter comprises a blend of the reactive material and the inert material; and
a weight fraction of the reactive material in the blend is in a range from 10% to 90%.
12. The device of claim 3 , wherein the cap comprises a glass material.