Semiconductor device assembly interconnection pillars and associated methods

A semiconductor device assembly, comprising:

• a first semiconductor die;
• a second semiconductor die;
• and
• an interconnection structure directly electrically coupling the first and the second semiconductor dies, the interconnection structure including:
• a first interconnection structure portion formed on the first semiconductor die, the first interconnection structure portion having:
• a first conductive pillar with a first bonding surface,
• a first annular barrier layer surrounding a sidewall of the first conductive pillar, and
• a first annular solder layer surrounding an outer surface of the first annular barrier layer;
• and
• a second interconnection structure portion at the second semiconductor die, the second interconnection structure portion having a second conductive pillar with a second bonding surface coupled to the first bonding surface.

A method of manufacturing a semiconductor device assembly, the method comprising:

• forming a first interconnection structure portion on a first semiconductor die, the forming the first interconnection structure portion including:
• forming a first conductive pillar extending from the first semiconductor die and extending to a height above the first semiconductor die,
• forming a first annular barrier layer surrounding a first sidewall of the first conductive pillar, and
• forming a first annular solder layer surrounding the first annular barrier layer such that the first annular solder layer extends to the height;
• forming a second interconnection structure portion on a second semiconductor die, the forming the second interconnection structure portion including forming a second conductive pillar extending from the second semiconductor die;
• aligning the first semiconductor die and the second semiconductor die with a bonding surface of the first conductive pillar opposing a bonding surface of the second conductive pillar;
• and
• coupling the first semiconductor die and the second semiconductor die together by reflowing a portion of the first annular solder layer around a second sidewall of the second conductive pillar.