Hermetically sealed wafer packages

A hermetically sealed semiconductor wafer package, the package comprising:

• a first bond ring on a first wafer;
• a second bond ring on a second wafer, wherein a surface of the second bond ring faces a complementary surface of the first bond ring;
• first and second standoffs of a first material, having a first thickness, formed on the surface of the first bond ring;
• and
• a eutectic alloy formed between the first and second standoffs and the first and second bond rings from a second material and the first material to create a hermetic seal between the first and second wafers, the eutectic alloy formed by heating the first and second materials to a temperature above a reflow temperature of the second material.

A method of bonding together two semiconductor wafers, the method comprising:

• forming a first bond ring on a surface of a first wafer;
• forming a second bond ring on a surface of a second wafer, wherein a surface of the second bond ring faces a complementary surface of the first bond ring;
• forming first and second standoffs of a same first material, each having a same first thickness, on the first bond ring surface;
• forming a layer of a second material, having a second thickness, between the first and second standoffs on the surface of the first bond ring or the surface of the second bond ring;
• heating the first and second wafers to a temperature above a reflow temperature of the second material, causing the second material to reflow, and forming a eutectic alloy comprising the first and second materials and creating a hermetic seal between the first and second bond rings;
• and
• annealing the first and second materials, causing the first material to diffuse into the second material,
• wherein the first and second standoffs maintain a pre-specified distance between the first and second bond rings.