A method for forming a package structure includes forming an under bump metallization (UBM) layer over a metal pad and forming a photoresist layer over the UBM layer. The method further includes patterning the photoresist layer to form an opening in the photoresist layer. The method also includes forming a first bump structure over the first portion of the UBM layer. The first bump structure includes a first barrier layer over a first pillar layer. The method includes placing a second bump structure over the first bump structure. The second bump structure includes a second barrier layer over a second pillar layer. The method further includes reflowing the first bump structure and the second bump structure to form a solder joint between a first inter intermetallic compound (IMC) and a second IMC.

An SiC semiconductor device includes an SiC semiconductor layer including an SiC monocrystal and having a first main surface as an element forming surface, a second main surface at a side opposite to the first main surface, and a plurality of side surfaces connecting the first main surface and the second main surface, and a plurality of modified lines formed one layer each at the respective side surfaces of the SiC semiconductor layer and each extending in a band shape along a tangential direction to the first main surface of the SiC semiconductor layer and modified to be of a property differing from the SiC monocrystal.

An SiC semiconductor device includes an SiC semiconductor layer including an SiC monocrystal and having a first main surface as an element forming surface, a second main surface at a side opposite to the first main surface, and a plurality of side surfaces connecting the first main surface and the second main surface, and a plurality of modified lines formed one layer each at the respective side surfaces of the SiC semiconductor layer and each extending in a band shape along a tangential direction to the first main surface of the SiC semiconductor layer and modified to be of a property differing from the SiC monocrystal.

A method of joining a semiconductor die to a substrate includes: applying a solder preform to a metal region of the semiconductor die or to a metal region of the substrate, the solder preform having a maximum thickness of 30 μm and a lower melting point than both metal regions; forming a soldered joint between the metal region of the semiconductor die and the metal region of the substrate via a diffusion soldering process and without applying pressure directly to the die; and setting a soldering temperature of the diffusion soldering process so that the solder preform melts and fully reacts with the metal region of the semiconductor die and the metal region of the substrate to form one or more intermetallic phases throughout the entire soldered joint, each intermetallic phase having a melting point above the melting point of the preform and the soldering temperature.

A method of joining a semiconductor die to a substrate includes: applying a solder preform to a metal region of the semiconductor die or to a metal region of the substrate, the solder preform having a maximum thickness of 30 μm and a lower melting point than both metal regions; forming a soldered joint between the metal region of the semiconductor die and the metal region of the substrate via a diffusion soldering process and without applying pressure directly to the die; and setting a soldering temperature of the diffusion soldering process so that the solder preform melts and fully reacts with the metal region of the semiconductor die and the metal region of the substrate to form one or more intermetallic phases throughout the entire soldered joint, each intermetallic phase having a melting point above the melting point of the preform and the soldering temperature.

A method includes forming a solder layer on a surface of one or more chips. A lid is positioned over the solder layer on each of the one or more chips. Heat and pressure are applied to melt the solder layer and attach each lid to a corresponding solder layer. The solder layer has a thermal conductivity of ≥50 W/mK.

A method includes forming a solder layer on a surface of one or more chips. A lid is positioned over the solder layer on each of the one or more chips. Heat and pressure are applied to melt the solder layer and attach each lid to a corresponding solder layer. The solder layer has a thermal conductivity of ≥50 W/mK.

Provided is a highly reliable semiconductor device capable of reducing stress generated in a semiconductor element even when a highly elastic joining material such as a Pb-free material is used in a power semiconductor having a double-sided mounting structure. The semiconductor device includes a semiconductor element including a gate electrode only on one surface, an upper electrode connected to the surface of the semiconductor element on which the gate electrode is provided, and a lower electrode connected to a surface opposite to the surface of the semiconductor element on which the gate electrode is provided. A connection end portion of the upper electrode with the surface of the semiconductor element on which the gate electrode is provided is located inside an end portion of the surface of the semiconductor element on which the gate electrode is provided, and a connection end portion of the lower electrode with the opposite surface of the semiconductor element is located inside an end portion of the opposite surface of the semiconductor element.

Provided is a highly reliable semiconductor device capable of reducing stress generated in a semiconductor element even when a highly elastic joining material such as a Pb-free material is used in a power semiconductor having a double-sided mounting structure. The semiconductor device includes a semiconductor element including a gate electrode only on one surface, an upper electrode connected to the surface of the semiconductor element on which the gate electrode is provided, and a lower electrode connected to a surface opposite to the surface of the semiconductor element on which the gate electrode is provided. A connection end portion of the upper electrode with the surface of the semiconductor element on which the gate electrode is provided is located inside an end portion of the surface of the semiconductor element on which the gate electrode is provided, and a connection end portion of the lower electrode with the opposite surface of the semiconductor element is located inside an end portion of the opposite surface of the semiconductor element.

Described herein is a composition including copper ions, an acid, and at least one polyaminoamide including, a group of formula L1

[A-B-A′-Z].sub.n[Y—Z].sub.m  (L1)

where

B is a diacid fragment of formula L2

##STR00001##

A, A′ are amine fragments independently selected from the group consisting of formula L3a

##STR00002## and formula L3b

##STR00003##

Y is a co-monomer fragment;
Z is a coupling fragment of formula L4

##STR00004##

n is an integer of from 1 to 400; and
m is 0 or an integer of from 1 to 400.