A method of soldering includes providing a substrate having a first metal joining surface, providing a semiconductor die having a second metal joining surface, providing a solder preform having a first interface surface and a second interface surface, arranging the solder preform between the substrate and the semiconductor die such that the first interface surface faces the first metal joining surface and such that the second interface surface faces the second metal joining surface, and performing a mechanical pressure-free diffusion soldering process that forms a soldered joint between the substrate and the semiconductor die by melting the solder preform and forming intermetallic phases in the solder. One or both of the first interface surface and the second interface surface has a varying surface profile that creates voids between the solder preform and one or both of the substrate and the semiconductor die before the melting of the solder preform.

Some implementations of the disclosure relate to a lead-free solder paste with mixed solder powders that is particularly suitable for high temperature soldering applications involving multiple board-level reflow operations. In one implementation, the solder paste consists of 10 wt % to 90 wt % of a first solder alloy powder, the first solder alloy powder consisting of an SnSbCuAg solder alloy that has a wt % ratio of Sn:Sb of 0.75 to 1.1; 10 wt % to 90 wt % of a second solder alloy powder, the second solder alloy powder consisting of an Sn solder alloy including at least 80 wt % of Sn; and a remainder of flux.

The present disclosure relates to a microelectronics package with significantly reduced delamination/cracking at solder joints, and a process for making the same. The disclosed microelectronics package includes a carrier, a solder joint region over the carrier, a top intermetallic (IMC) layer over the solder joint region, and a device die over the top IMC layer. Herein, the device die includes a substrate, an active device over the substrate, a top barrier layer underneath the substrate, and a backside metal layer vertically between the top IMC layer and the top barrier layer. The backside metal layer is formed of gold (Au) with a thickness at least 0.5 μm. The top IMC layer comprises gold nickel tin (AuNiSn) or gold platinum tin (AuPtSn), and the solder joint region comprises an Au-rich gold-tin (Au.sub.5Sn) and gold-tin (AuSn) eutectic mixture.

A semiconductor package includes a power semi conductor chip comprising SiC, a leadframe part including Cu, wherein the power semiconductor chip is arranged on the leadframe part, and a solder joint electrically and mechanically coupling the power semiconductor chip to the leadframe part, wherein the solder joint includes at least one intermetallic phase.

A display panel and method of manufacture are described. In an embodiment, a display substrate includes a pixel area and a non-pixel area. An array of subpixels and corresponding array of bottom electrodes are in the pixel area. An array of micro LED devices are bonded to the array of bottom electrodes. One or more top electrode layers are formed in electrical contact with the array of micro LED devices. In one embodiment a redundant pair of micro LED devices are bonded to the array of bottom electrodes. In one embodiment, the array of micro LED devices are imaged to detect irregularities.

A semiconductor device and method is disclosed. In one embodiment, the semiconductor device comprises a semiconductor die comprising a first surface and a second surface opposite to the first surface, a first metallization layer disposed on the first surface of the semiconductor die, a first solder layer disposed on the first metallization layer, wherein the first solder layer contains the compound Sn/Sb, and a first contact member comprising a Cu-based base body and a Ni-based layer disposed on a main surface of the Cu-based base body, wherein the first contact member is connected with the Ni-based layer to the first solder layer.

A batch soldering method includes providing a first passive device, arranging the first passive device on a first metal region of a substrate with a region of first solder material between the first passive device and the substrate, providing a semiconductor die, arranging the semiconductor die on a second metal region of the substrate with a region of second solder material between the semiconductor die and the substrate, and performing a common soldering step that simultaneously forms a first soldered joint from the region of first solder material and forms a second soldered joint from the region of second solder material. The common soldering step is performed at a soldering temperature such that one or more intermetallic phases form within the second soldered joint, each of the one or more intermetallic phases having a melting point above the second solder material and the soldering temperature.

A semiconductor device includes a semiconductor die with a metallization layer including a first metal with a comparatively high melting point, a die carrier including a second metal with a comparatively high melting point, a first intermetallic compound arranged between the semiconductor die and the die carrier and including the first metal and a third metal with a comparatively low melting point, a second intermetallic compound arranged between the first intermetallic compound and the die carrier and including the second metal and the third metal, and precipitates of a third intermetallic compound arranged between the first intermetallic compound and the second intermetallic compound and including the third metal and a fourth metal with a comparatively high melting point.

Disclosed herein are lids for integrated circuit (IC) packages with solder thermal interface materials (STIMs), as well as related methods and devices. For example, in some embodiments, an IC package may include a STIM between a die of the IC package and a lid of the IC package. The lid of the IC package may include nickel, the IC package may include an intermetallic compound (IMC) between the STIM and the nickel, and the lid may include an intermediate material between the nickel and the IMC.

Disclosed herein are lids for integrated circuit (IC) packages with solder thermal interface materials (STIMs), as well as related methods and devices. For example, in some embodiments, an IC package may include a STIM between a die of the IC package and a lid of the IC package. The lid of the IC package may include nickel, the IC package may include an intermetallic compound (IMC) between the STIM and the nickel, and the lid may include an intermediate material between the nickel and the IMC.