A method of forming a semiconductor package. Implementations include forming on a die backside an intermediate metal layer having multiple sublayers, each including a metal selected from the group consisting of titanium, nickel, copper, silver, and combinations thereof. A tin layer is deposited onto the intermediate metal layer and is then reflowed with a silver layer of a substrate to form an intermetallic layer having a melting temperature above 260 degrees Celsius and including an intermetallic consisting of silver and tin and/or an intermetallic consisting of copper and tin. Another method of forming a semiconductor package includes forming a bump on each of a plurality of exposed pads of a top side of a die, each exposed pad surrounded by a passivation layer, each bump including an intermediate metal layer as described above and a tin layer coupled to the intermediate metal layer is reflowed to form an intermetallic layer.

A process for forming a semiconductor package is disclosed. The process includes providing a first substrate including a first dielectric layer. The process includes overlaying a first surface of the first dielectric layer with a first bonding layer that includes aluminum. The process includes providing a second substrate including a second dielectric layer. The process includes overlaying a second surface of the second dielectric layer with a second bonding layer that includes alkoxy-siloxide. The process includes forming a third bonding layer by combining the first bonding layer and the second bonding layer so as to bond the first substrate to the second substrate.

A process for forming a semiconductor package is disclosed. The process includes providing a first substrate including a first dielectric layer. The process includes overlaying a first surface of the first dielectric layer with a first bonding layer that includes aluminum. The process includes providing a second substrate including a second dielectric layer. The process includes overlaying a second surface of the second dielectric layer with a second bonding layer that includes alkoxy-siloxide. The process includes forming a third bonding layer by combining the first bonding layer and the second bonding layer so as to bond the first substrate to the second substrate.

An integrated circuit (IC) die structure comprises a substrate material comprising silicon. Integrated circuitry is over a first side of the substrate material. A composite layer is in direct contact with a second side of the substrate material. The second side is opposite the first side. The composite layer comprises a first constituent material associated with a first linear coefficient of thermal expansion (CTE), and a first thermal conductivity exceeding that of the substrate. The composite layer also comprises a second constituent material associated with a second CTE that is lower than the first, and a second thermal conductivity exceeding that of the substrate.