Abstract: A method for forming routing conductors and solder bumps on a microelectronic substrate includes the steps of forming an under bump metallurgy layer on the substrate and forming a solder structure on the under bump metallurgy layer where the solder structure includes an elongate portion and an enlarged width portion. The portions of the under bump metallurgy layer not covered by the solder structure can be selectively removed using the solder structure as a mask. In addition, the solder is caused to flow from the elongate portion of the solder structure to the enlarged width solder portion thereby forming a raised solder bump. This step is preferably performed by heating the solder structure above its liquidus temperature allowing surface tension induced internal pressures to affect the flow. Various solder structures are also disclosed.

Abstract: A controlled-shaped solder reservoir provides additional solder to a bump in the step for increasing the volume of solder forming the solder bump. The controlled shaped reservoirs can be shaped and sized to provide predetermined amounts of solder to the solder bump. Thus, the height of the resulting solder bump can be predetermined. The solder reservoirs can be shaped to take a minimum amount of space, such as by at least partially wrapping around the solder bump. Consequently, the solder bumps may have increased height without adding to the space requirements of the solder bump, or without increasing the fabrication cost. In addition, due to the finite time required for solder flow, a means of sequencing events during soldering is provided.

Abstract: A controlled-shaped solder reservoir provides additional solder to a bump in the flow step for increasing the volume of solder forming the solder bump. The controlled shaped reservoirs can be shaped and sized to provide predetermined amounts of solder to the solder bump. Thus, the height of the resulting solder bump can be predetermined. The solder reservoirs can be shaped to take a minimum amount of space, such as by at least partially wrapping around the solder bump. Consequently, the solder bumps may have increased height without adding to the space requirements of the solder bump, or without increasing the fabrication cost. In addition, due to the finite time required for solder flow, a means of sequencing events during soldering is provided.

Abstract: A flip-ship structure having a semiconductor substrate including an electronic device formed thereon, a contact pad on said semiconductor substrate electrically connected to said electronic device, a passivation layer on said semiconductor substrate and on said contact pad wherein said passivation layer defines a contact hole therein exposing a portion of said contact pad, an under-bump metallurgy structure on said passivation layer electrically contacting said portion of said contact pad that is exposed; and a solder structure on said under-bump metallurgy structure opposite said semiconductor substrate, said solder structure including an elongate portion on said elongate portion of said metallurgy structure opposite said contact pad and an enlarged width portion on said enlarged width portion of said metallurgy structure opposite said passivation layer.