A semiconductor structure includes a substrate; a pad disposed over the substrate; a passivation disposed over the substrate and exposing a portion of the pad; and a bump disposed over the portion of the pad. The bump includes a buffering member disposed over the portion of the pad; and a conductive layer surrounding the buffering member and electrically connected to the pad.

A semiconductor structure includes a substrate; a pad disposed over the substrate; a passivation disposed over the substrate and exposing a portion of the pad; and a bump disposed over the portion of the pad. The bump includes a buffering member disposed over the portion of the pad; and a conductive layer surrounding the buffering member and electrically connected to the pad.

A bump electrode is formed on an electrode pad using a Cu core ball in which a core material is covered with solder plating, and a board which has bump electrodes such as semiconductor chip or printed circuit board mounts such a bump electrode. Flux is coated on a substrate and the bump electrodes are then mounted on the electrode pad. In a step of heating the electrode pad and the Cu core ball to melt the solder plating, a heating rate of the substrate is set to have not less than 0.01 C./sec and less than 0.3.

An embodiment bump on trace (BOT) structure includes a contact element supported by an integrated circuit, an under bump metallurgy (UBM) feature electrically coupled to the contact element, a metal ladder bump mounted on the under bump metallurgy feature, the metal ladder bump having a first tapering profile, and a substrate trace mounted on a substrate, the substrate trace having a second tapering profile and coupled to the metal ladder bump through direct metal-to-metal bonding. An embodiment chip-to-chip structure may be fabricated in a similar fashion.

A bump structure includes a contact element formed on a substrate and a passivation layer overlying the substrate. The passivation layer includes a passivation opening exposing the contact element. The bump structure also includes a polyimide layer overlying the passivation layer and an under bump metallurgy (UBM) feature electrically coupled to the contact element. The polyimide layer has a polyimide opening exposing the contact element, and the under bump metallurgy feature has a UBM width. The bump structure further includes a copper pillar on the under bump metallurgy feature. A distal end of the copper pillar has a pillar width, and the UBM width is greater than the pillar width.

Representative implementations of devices and techniques provide interconnect structures and components for coupling various carriers, printed circuit board (PCB) components, integrated circuit (IC) dice, and the like, using tall and/or fine pitch physical connections. Multiple layers of conductive structures or materials are arranged to form the interconnect structures and components. Nonwettable barriers may be used with one or more of the layers to form a shape, including a pitch of one or more of the layers.

Process for manufacturing electronic components with wettable flanks from a substrate covered by connection terminals and in which chips are formed, the process comprising the following steps: a) solder connection pads to the connection terminals, b) coat the connection pads with a layer of insulating resin, c) thin the insulating resin layer until it reaches the core of the connection pads, d) form cavities by removing part of the connection pads and part of the insulating resin layer, so as to make part of the flanks of the components accessible, e) deposit a layer of conductive material on the flanks of the components and on the connection pads, f) separate the chips.