Patent ID: 9257338
Filing Date: 2016-02-09
CPC Classification: H01L

Claim Text:
1. A method of fabricating a stacked assembly, comprising steps of: providing a first substrate and a second substrate, each having a cylindrical trench with an extensional part surrounding the cylindrical trench; forming a barrier layer and a seed layer on the surfaces of the first and second substrates, so that the barrier layer and the seed layer are confirmally formed on sidewalls and bottoms of the cylindrical trenches and the extensional parts; forming a first conductor layer on the seed layer of the first substrate, so that the first conductor layer under-fills the cylindrical trench and the extensional part of the first substrate, with a recess formed in the first conductor layer in the cylindrical trench; removing, from top to bottom, a part of the first conductor layer, the barrier layer and the seed layer until a top surface of the first substrate is exposed, so that the recess remains in the first conductor layer in the cylindrical trench; forming a second conductor layer on the seed layer of the second substrate, so that the second conductor layer over-fills the cylindrical trench and the extensional part of the second substrate, with a protrusion formed on the second conductor layer in the cylindrical trench; etching to remove a part of the second conductor layer as well as the barrier layer and the seed layer exceeding a top surface of the second substrate, so that the protrusion remains on the second conductor layer in the cylindrical trench; forming a solder layer on the first and second substrates, so that the solder layer is formed in the recess of the first substrate and on the protrusion of the second substrate; and stacking the first substrate on the second substrate, with the recess corresponded with the protrusion.