Subassembly that includes a power semiconductor die and a heat sink having an exposed surface portion thereof

A method for forming a semiconductor assembly, comprising:

• forming a first patterned polymer layer on a first surface of a heat sink to define an exposed portion of the first surface, said exposed portion of the first surface extending radially inward along the heat sink surface from the first layer;
• forming a second patterned polymer layer on a radially outer portion of the first patterned polymer layer, said first and second layers defining a cell for accommodating a power semiconductor die;
• applying a solder material onto the exposed portion of the heat sink surface and in the cell;
• positioning a power semiconductor die within the cell on a radially inward portion of the first layer so that the die is thermally coupled to the heat sink by the solder material;
• forming a packaging patterned polymer layer on a second surface of the heat sink opposing the first surface and defining an interior surface portion of the heat sink;
• and
• forming a semiconductor package in which the heat sink, solder material and die are located such that the interior surface portion of the second surface of the heat sink is not enclosed by the semiconductor package.

A method for forming a semiconductor assembly, comprising:

• forming a first patterned polymer layer on a first surface of a heat sink to define an exposed portion of the first surface, said exposed portion of the first surface extending radially inward along the heat sink surface from the first layer;
• forming a second patterned polymer layer on a radially outer portion of the first patterned polymer layer, said first and second layers defining a cell for accommodating a power semiconductor die;
• applying a solder material onto the exposed portion of the heat sink surface and in the cell;
• positioning a power semiconductor die within the cell on a radially inward portion of the first layer so that the die is thermally coupled to the heat sink by the solder material;
• applying removable tape onto a second surface of the heat sink opposing the first surface and defining an interior surface portion of the heat sink;
• forming a semiconductor package in which the heat sink, solder material and die are located;
• and
• removing the removable tape from the second surface of the heat sink to thereby expose the interior surface portion of the heat sink.