Hermetically sealed micro-device package with window

A micro-device module including:

• a package base;
• a micro-device mounted on the package base;
• and
• a cover assembly welded to the package base so as to encapsulate the micro-device in a hermetically sealed cavity formed therebetween, the cover assembly including
• a weldable frame having a continuous sidewall defining a frame aperture therethrough, the sidewall including a frame seal-ring area circumscribing the frame aperture, the frame seal-ring area having a metallic surface;
• a sheet of a transparent material having a window portion defined thereupon, the window portion having finished top and bottom surfaces, the sheet being hermetically bonded to the frame by preparing a sheet seal-ring area on the sheet, the sheet seal-ring area circumscribing the window portion, metallizing the prepared sheet seal-ring area of the sheet, positioning the frame against the sheet such that at least a portion of the frame seal-ring area and at least a portion of the sheet seal-ring area contact one another along a continuous junction region that circumscribes the window portion, and heating the junction region until a metal-to-metal joint is formed between the frame and sheet all along the junction region, whereby a hermetic seal circumscribing the window portion is formed.