Abstract:
A method for forming solder bumps on an electronic structure including the steps of first providing a mold made by a sheet of a mold material having a thickness greater than that of the solder bumps to be formed, the mold material has sufficient optical transparency so as to allow the inspection of a solder material subsequently filled into the mold cavities that are formed in the mold material, and a coefficient of thermal expansion that is substantially similar to the substrate which the mold will be mated to, forming a multiplicity of mold cavities in the sheet of mold material, filling the multiplicity of mold cavities with a solder material, cooling the mold to a temperature that is sufficient to solidify the solder material in the multiplicity of mold cavities, positioning the mold intimately with the electronic structure such that the cavities facing the structure, and heating the mold and the structure together to a temperature sufficiently high such that the solder material transfers onto the electronic structure.
Abstract:
A method for forming solder bumps on an electronic structure including the steps of first providing a mold made by a sheet of a mold material having a thickness greater than that of the solder bumps to be formed, the mold material has sufficient optical transparency so as to allow the inspection of a solder material subsequently filled into the mold cavities that are formed in the mold material, and a coefficient of thermal expansion that is substantially similar to the substrate which the mold will be mated to, forming a multiplicity of mold cavities in the sheet of mold material, filling the multiplicity of mold cavities with a solder material, cooling the mold to a temperature that is sufficient to solidify the solder material in the multiplicity of mold cavities, positioning the mold intimately with the electronic structure such that the cavities facing the structure, and heating the mold and the structure together to a temperature sufficiently high such that the solder material transfers onto the electronic structure.
Abstract:
A solder decal is produced by a method wherein a decal strip having a plurality of anchor holes is aligned with a mold having a plurality of cells. Liquid solder is injected into the anchor holes and mold cells, and is then allowed to cool to solidify therein. The mold may be separated from the decal strip to form the solder decal containing solder beads each having a stem mechanically joined to the strip at respective ones of the anchor holes. Various forms of the solder decal are used for transferring the solder beads to a substrate or chip, or effecting temporary connections for conducting burn-in and testing, or accommodating thermal mismatch for example.
Abstract:
A microcavity structure is provided. The structure comprises a cavity layout that enables centering of reflowed solder at each of one or more interconnect locations and protrusion of the reflowed solder sufficiently from the cavity to facilitate wetting. Techniques are also provided for producing a microcavity structure, for using injection molded solder (IMS) for micro bumping, as well as for using injection molded solder (IMS) for three-dimensional (3D) packaging.
Abstract:
A process and tools for forming spherical metal balls is described incorporating molds, injection molded solder, a liquid or gaseous environment to reduce or remove metal oxides and an unconstrained reflow of metal in a heated liquid or gas and solidification of molten metal in a cooler liquid or gas.
Abstract:
There is provided a method for applying solder to an element on a surface of a substrate. The method comprises the steps of (a) placing a mold over the surface, where the mold includes a conduit that contains the solder, and (b) heating the solder to a molten state so that the solder flows from the conduit onto the element. The conduit enjoys two degrees of horizontal freedom with respect to the surface such that the conduit becomes substantially aligned with the element when the solder is in the molten state. There is also provided a system for applying solder to an element on a surface of a substrate.
Abstract:
A precise volume, precisely registerable carrier is provided for use with injection molding for producing integrated circuit bump contacts in the "flip chip" technology. A hemispherical cavity is produced by etching through and undercutting a registered opening into a transparent carrier. The hemispherical cavity has related specific volume and visible peripheral shape that permits simple optical quality control when the injection molding operation has filled the cavity and simple optical registration for fusing to the pads on the integrated circuit.
Abstract:
Disclosed is a solder injection mold apparatus and method for providing solder balls to a printed circuit board substrate using the solder injection mold apparatus in the plastic ball grid array (PBGA). The solder mold through holes are chamfered at entry and at exit ends to assist in receipt of molten solder and the formation and transfer of solder balls to lands on the substrate. A blind recess is provided in the second major surface of the mold, i.e. the side facing the substrate, in order to accommodate electronic components mounted thereon. Solder balls are delivered and metallurgically affixed to the lands in a process that requires only one reflow, leaving the through holes clean of solder and the mold ready for reuse. The material of which the substrate, mold and base plate are comprised is selected to be non-wettable by solder and mutually compatible with respect to CTE when exposed to temperatures of molten solder.
Abstract:
A method for forming alloy deposits at selected areas on a receiving substrate includes the steps of: providing an alloy carrier including at least a first decal including a first plurality of openings and a second decal including a second plurality of openings, the first and second decals being arranged such that each of the first plurality of openings is in alignment with a corresponding one of the second plurality of openings; filling the first and second plurality of openings with molten alloy; cooling the molten alloy to thereby form at least first and second plugs, the first plug having a first surface and a second surface substantially parallel to one another, the second plug having a third surface and a fourth surface substantially parallel to one another; removing at least one of the first and second decals to at least partially expose the first and second plugs; aligning the alloy carrier with the receiving substrate so that the first and second plugs correspond to the selected areas on the receiving substrate; and transferring the first plug to a first of the selected areas and the second plug to a second of the selected areas.
Abstract:
A method for forming alloy deposits at selected areas on a receiving substrate includes the steps of: providing an alloy carrier including at least a first decal including a first plurality of openings and a second decal including a second plurality of openings, the first and second decals being arranged such that each of the first plurality of openings is in alignment with a corresponding one of the second plurality of openings; filling the first and second plurality of openings with molten alloy; cooling the molten alloy to thereby form at least first and second plugs, the first plug having a first surface and a second surface substantially parallel to one another, the second plug having a third surface and a fourth surface substantially parallel to one another; removing at least one of the first and second decals to at least partially expose the first and second plugs; aligning the alloy carrier with the receiving substrate so that the first and second plugs correspond to the selected areas on the receiving substrate; and transferring the first plug to a first of the selected areas and the second plug to a second of the selected areas.