Structure and method of making sealed capped chips
A method of making a plurality of sealed assemblies is provided which includes a) assembling a first element to a second element so that a bottom surface of the first element faces downwardly toward a front surface of the second element and a top surface of the first element faces upwardly away from the second element; and (b) forming ring seals surrounding regions of the front surface of the second element by introducing flowable material between the first element and the second element from the top surface of the first element through openings in the first element. A chip is provided which includes: (a) a body defining a front surface and one or more circuit elements on or within the body; (b) one or more bond pads exposed at the front surface in a bond pad region; and (c) a metallic ring exposed at the front surface, the ring substantially surrounding the bond pad region. Sealed chip assemblies are formed by sealing an array of the chips, e.g., in wafer form, to a cap element.
1. A capped chip, comprising:
a chip having a front surface, one or more devices at said front surface, and a first annular solder-wettable metallization enclosing said one or more devices;
a cap member having a top surface, a bottom surface opposite said top surface, one or more through holes extending between said top and bottom surfaces and a second annular solder-wettable metallization at said bottom surface in registration with said one or more through holes and said first annular solder-wettable metallization; and
a sealing medium including a fusible material bonded to said first and second solder-wettable metallizations.
2. The capped chip as claimed in claim 1 , wherein said sealing medium includes at least one material selected from the group consisting of solder, eutectic composition, and tin.
3. The capped chip as claimed in claim 2 , wherein said one or more through holes is sized to permit a flow of said sealing medium from said one or more through holes onto said first and second annular solder-wettable metallizations.
4. The capped chip as claimed in claim 3 , wherein said one or more through holes is tapered to become smaller in a direction from said top surface of said cap member towards said bottom surface.
5. The capped chip as claimed in claim 3 , wherein said chip further includes a plurality of bond pads exposed at said front surface enclosed by said first annular solder-wettable metallization, and a plurality of metallic interconnects extending from said bond pads at least partially through said cap member.