A cryogenic under bump metallization (UBM) stack includes an adhesion and barrier layer and a conductive pillar on the adhesion and barrier layer. The conductive pillar functions as a solder wetting layer of the UBM stack and has a thickness. An indium superconducting solder bump is on the conductive pillar. The thickness of the conductive pillar is sufficient to prevent intermetallic regions, which form in the conductive pillar at room temperature due to interdiffusion, from extending through the entire thickness of the conductive pillar to maintain the structural integrity of the UBM stack. The indium (In) solder bump may be formed through electroplating, with the conductive pillar being copper (Cu) and the adhesion and barrier layer being titanium tungsten (TiW) and a thin seed layer of copper (Cu), or a layer of titanium (Ti). The UBM stack eliminates the need for magnetic materials such as nickel (Ni) in the stack, making the stack suitable for cryogenic applications.

A light emitting display device includes a pixel circuit unit, a data distribution unit, a plurality of signal generating units, a unit light emitting diode, and a dummy opening. The pixel circuit unit is configured to generate an output current. The data distribution unit is configured to apply a data voltage to the pixel circuit unit through a data line. The plurality of signal generating units are respectively configured to apply a scan signal and a light emission control signal to the pixel circuit unit through a plurality of signal lines. The unit light emitting diode is configured to receive the output current of the pixel circuit unit and is attached to the pixel circuit unit. The dummy opening is formed in the region where the pixel circuit unit, the data distribution unit, and a plurality of signal generating units are not positioned.

A method for fabricating a semiconductor structure is provided. The method includes: providing a semiconductor chip comprising an active surface; forming a conductive bump over the active surface of the semiconductor chip; and coupling the conductive bump to a substrate. The conductive bump includes a plurality of bump segments including a first group of bump segments and a second group of bump segments. Each bump segment has a same segment thickness in a direction orthogonal to the active surface of the semiconductor chip, and each bump segment has a volume defined by a multiplication of the same segment thickness with an average cross-sectional area of the bump segment in a plane parallel to the active surface of the semiconductor chip. A ratio of a total volume of the first group of bump segments to a total volume of the second group of bump segments is between 0.03 and 0.8.

A semiconductor package including a first semiconductor chip, a second semiconductor chip disposed on the first semiconductor chip, and a third semiconductor chip disposed on the second semiconductor chip. A first pad is disposed on a top surface of the second semiconductor chip, and includes a first portion and a second portion protruding in a vertical direction from the first portion. A width of the first portion in a first horizontal direction is greater than a width of the second portion in the first horizontal direction. A second pad is disposed on a bottom surface of the third semiconductor chip facing the top surface of the second semiconductor chip, and a solder ball is disposed as surrounding a sidewall of the second portion of the first pad between the first pad and the second pad.

In a semiconductor device, a semiconductor element includes a semiconductor substrate, a surface electrode and a protective film. The semiconductor substrate has an active region and an outer peripheral region. The surface electrode includes a base electrode disposed on a front surface of the semiconductor substrate and a connection electrode disposed on the base electrode. The protective film covers a peripheral end portion of the base electrode and an outer peripheral edge of the connection electrode. The protective film has an opening to expose the connection electrode so as to enable a solder connection. A boundary between the outer peripheral edge of the connection electrode and the protective film is located at a position corresponding to the outer peripheral region in a plan view.

A method includes forming a first substrate including a first dielectric layer and a first metal pad, forming a second substrate including a second dielectric layer and a second metal pad, and bonding the first dielectric layer to the second dielectric layer, and the first metal pad to the second metal pad. One or both of the first and second substrates is formed by forming a first insulating layer, forming an opening in the layer, forming a barrier on an inner surface of the opening, forming a metal pad material on the barrier, polishing the metal pad material to expose a portion of the barrier and to form a gap, expanding the gap, forming a second insulating layer to fill the opening and the gap, and polishing the insulating layers such that a top surface of the metal pad is substantially planar with an upper surface of the polished layer.

Semiconductor dies including ultra-thin wafer backmetal systems, microelectronic devices containing such semiconductor dies, and associated fabrication methods are disclosed. In one embodiment, a method for processing a device wafer includes obtaining a device wafer having a wafer frontside and a wafer backside opposite the wafer frontside. A wafer-level gold-based ohmic bond layer, which has a first average grain size and which is predominately composed of gold, by weight, is sputter deposited onto the wafer backside. An electroplating process is utilized to deposit a wafer-level silicon ingress-resistant plated layer over the wafer-level Au-based ohmic bond layer, while imparting the plated layer with a second average grain size exceeding the first average grain size. The device wafer is singulated to separate the device wafer into a plurality of semiconductor die each having a die frontside, an Au-based ohmic bond layer, and a silicon ingress-resistant plated layer.

Semiconductor dies including ultra-thin wafer backmetal systems, microelectronic devices containing such semiconductor dies, and associated fabrication methods are disclosed. In one embodiment, a method for processing a device wafer includes obtaining a device wafer having a wafer frontside and a wafer backside opposite the wafer frontside. A wafer-level gold-based ohmic bond layer, which has a first average grain size and which is predominately composed of gold, by weight, is sputter deposited onto the wafer backside. An electroplating process is utilized to deposit a wafer-level silicon ingress-resistant plated layer over the wafer-level Au-based ohmic bond layer, while imparting the plated layer with a second average grain size exceeding the first average grain size. The device wafer is singulated to separate the device wafer into a plurality of semiconductor die each having a die frontside, an Au-based ohmic bond layer, and a silicon ingress-resistant plated layer.

A silver nano-twinned thin film structure and a method for forming the same are provided. A silver nano-twinned thin film structure, including: a substrate; an adhesive-lattice-buffer layer over the substrate; and a silver nano-twinned thin film over the adhesive-lattice-buffer layer, wherein the silver nano-twinned thin film comprises parallel-arranged twin boundaries, and a cross-section of the silver nano-twinned thin film reveals that 50% or more of all twin boundaries are parallel-arranged twin boundaries, wherein the parallel-arranged twin boundaries include Σ3 and Σ9 boundaries, wherein the Σ3 and Σ9 boundaries include 95% or more crystal orientation.

A silver nano-twinned thin film structure and a method for forming the same are provided. A silver nano-twinned thin film structure, including: a substrate; an adhesive-lattice-buffer layer over the substrate; and a silver nano-twinned thin film over the adhesive-lattice-buffer layer, wherein the silver nano-twinned thin film comprises parallel-arranged twin boundaries, and a cross-section of the silver nano-twinned thin film reveals that 50% or more of all twin boundaries are parallel-arranged twin boundaries, wherein the parallel-arranged twin boundaries include Σ3 and Σ9 boundaries, wherein the Σ3 and Σ9 boundaries include 95% or more crystal orientation.