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.

The invention relates to a vertical compound semiconductor structure having a substrate with a first main surface and an opposite second main surface, a vertical channel opening extending completely through the substrate between the first main surface and the second main surface and a layer stack arranged within the vertical channel opening. The layer stack includes an electrically conductive layer arranged within the vertical channel opening and a compound semiconductor layer arranged within the vertical channel opening. The compound semiconductor layer includes a compound semiconductor layer arranged on the electrically conductive layer and connected galvanically to the electrically conductive layer. Further, the invention relates to a method for producing such a vertical compound semiconductor structure.

The invention relates to a vertical compound semiconductor structure having a substrate with a first main surface and an opposite second main surface, a vertical channel opening extending completely through the substrate between the first main surface and the second main surface and a layer stack arranged within the vertical channel opening. The layer stack includes an electrically conductive layer arranged within the vertical channel opening and a compound semiconductor layer arranged within the vertical channel opening. The compound semiconductor layer includes a compound semiconductor layer arranged on the electrically conductive layer and connected galvanically to the electrically conductive layer. Further, the invention relates to a method for producing such a vertical compound semiconductor structure.

The present disclosure provides a semiconductor structure, including providing a first chip, disposing a first copper layer having a first thickness over a first side of the first chip, and disposing a first solder having a second thickness over the first copper layer, wherein a ratio of the second thickness and the first thickness is in a range of from about 2 to about 3.5.

The present disclosure provides a semiconductor structure, including providing a first chip, disposing a first copper layer having a first thickness over a first side of the first chip, and disposing a first solder having a second thickness over the first copper layer, wherein a ratio of the second thickness and the first thickness is in a range of from about 2 to about 3.5.

An electronic device is provided in the present disclosure. The electronic device includes a substrate and a light emitting diode. The light emitting diode is bonded to the substrate through a solder alloy. The solder alloy includes tin and a metal element M, and the metal element M is one of the indium and bismuth. The atomic percentage of tin in the sum of tin and the metal element M ranges from 60% to 90% in the solder alloy.

A package structure is provided. The package structure includes a first bump structure formed over a substrate, a solder joint formed over the first bump structure and a second bump structure formed over the solder joint. The first bump structure includes a first pillar layer formed over the substrate and a first barrier layer formed over the first pillar layer. The first barrier layer has a first protruding portion which extends away from a sidewall surface of the first pillar layer, and a distance between the sidewall surface of the first pillar layer and a sidewall surface of the first barrier layer is in a range from about 0.5 m to about 3 m. The second bump structure includes a second barrier layer formed over the solder joint and a second pillar layer formed over the second barrier layer, wherein the second barrier layer has a second protruding portion which extends away from a sidewall surface of the second pillar layer.

A nanowire bonding interconnect for fine-pitch microelectronics is provided. Vertical nanowires created on conductive pads provide a debris-tolerant bonding layer for making direct metal bonds between opposing pads or vias. Nanowires may be grown from a nanoporous medium with a height between 200-1000 nanometers and a height-to-diameter aspect ratio that enables the nanowires to partially collapse against the opposing conductive pads, creating contact pressure for nanowires to direct-bond to opposing pads. Nanowires may have diameters less than 200 nanometers and spacing less than 1 m from each other to enable contact or direct-bonding between pads and vias with diameters under 5 m at very fine pitch. The nanowire bonding interconnects may be used with or without tinning, solders, or adhesives. A nanowire forming technique creates a nanoporous layer on conductive pads, creates nanowires within pores of the nanoporous layer, and removes at least part of the nanoporous layer to reveal a layer of nanowires less than 1 m in height for direct bonding.

The copper pillars have improved integrity such that they can readily withstand the harsh reflow conditions of post solder bump application without readily failing. The method of making the copper pillars having the improved integrity involves a two-step electroplating process of varying current densities.

A package structure and method for forming the same are provided. The package structure includes a first interconnect structure formed over a first substrate, and the first interconnect structure includes a first metal layer. The package structure further includes a second interconnect structure formed over a second substrate. The package structure includes a bonding structure between the first interconnect structure and the second interconnect structure. The bonding structure includes a first intermetallic compound (IMC) and a second intermetallic compound (IMC), a portion of the first IMC protrudes from the sidewall surfaces of the second IMC, and there could be a grain boundary between the first IMC and the second IMC.