International Business Machines Corporation

Chon Cheong Lei

Peter Alfred Gruber

Krishna Gandhi Sachdev

Lannie R Bolde

James N Humenik

Glenn A Pomerantz

Umar M Ahmad

John Ulrich Knickerbocker

Peter Jeffrey Brofman

David Hirsch Danovitch

William F Beausoleil

Charles L Reynolds

Wai Mon Ma

Guy Paul Brouillette

James H Covell

Tak-kwong Ng

Horatio Quinones

Donald J Papae

Lawrence A Thomas

N James Tomassetti

Francis F Szenher

Michael Juergen Kessler

Jac Anders Burke

Donn Allan Lord

John J Ellison

Ellyn M Ingalls

Minkailu A Jalloh

Demian M Riccardi

Jorge L Rivera

Tim H Lee

Timothy W Donahue

An integrated circuit (IC) chip module includes at least one integrated circuit chip mounted upon a substrate, and a plurality of passive components mounted upon the substrate. A polymer based bib has at least one opening formed therein, the at least one opening configured to accommodate the at least one integrated circuit chip therein, and the bib further configured for attachment to one or more of the plurality of passive components. A protective cap is mounted over the at least one integrated circuit chip and attached to the substrate, wherein the bib is configured to retain thereon a thermally conductive paste initially applied to at least one of the integrated circuit chip and the protective cap.

Method and structure for selective thermal paste deposition and retention on integrated circuit chip modules

In a solder reflow type building of modular electrical apparatus involving integrated circuit and discrete components, fabrication operations are arranged to include the providing of a general type series of steps for each component element involving a reflow or joining step at the highest joining temperature, immediately followed by a solder flux cleaning step and immediately followed by a testing of the entire module constructed thus far. There is provided a further specific type operation for each different type of component element that includes the providing of a loop for the introduction of a replacement for any broken discrete component with joining being achieved with use of a lower fusion temperature solder, flux cleaning and testing at each joining followed by reinsertion into the module. There is further provided an operation at the encapsulation stage of the module building for introducing underfill between the component and supporting carrier.

Solder reflow type electrical apparatus packaging having integrated circuit and discrete components

A semi-aqueous solvent based method using non-aromatic, halogen-free organic solvent compositions for the effective removal of flux residue from electronic component surfaces after high temperature solder interconnections in the presence of rosin based flux compositions. Rosin flux residue can be removed using hydrophobic, essentially water insoluble, propylene glycol alkylether solvents in conjunction with a surfactant, preferably an ionic and/or a mixture of a non-ionic and an ionic surfactant in the first step, then a second step involving immersion with agitation in a hydrophobic solvent with no added surfactant. This is followed by a third step of hydrophilic solvent immersion with agitation/spray, rinsing off the hydrophilic solvent with water, and then a drying step.

Semi-aqueous solvent based method of cleaning rosin flux residue

A process of cleaning of objects that relate to semiconductor fabrication processes, such as, for example, conductive paste screening in the production of multilayer ceramic substrates and composite solder paste by stencil printing in electronic circuit assembly. Specifically, the process removes a metal/polymer composite paste from screening masks and associated paste making and processing equipment used in printing conductive metal pattern onto ceramic green sheet in the fabrication of semiconductor packaging substrates. The process also cleans solder paste residue from stencil printing equipment used in electronic module assembly surface mount technology for SMT discretes, solder column attachment, and BGA (Ball Grid Array) attachment on ceramic chip carrier or for screening solder paste onto printed circuit board. More particularly, paste residue is cleaned from metal, ceramic, and plastic substrates by a non-alkaline semi-aqueous cleaning method employing high boiling propylene glycol alkyl ether or mixtures of propylene glycol alkyl ether and propylene glycol solvents.

Semi-aqueous solvent cleaning of paste processing residue from substrates

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.

Method and apparatus for applying solder to an element on a substrate

A method of removing cured silicone polymer deposits from electronic components. The components are immersed in a preheated solution of a quaternary ammonium fluoride in a hydrophobic non-hydroxylic aprotic solvent with agitation. The components are then immersed in a preheated solvent consisting essentially of a hydrophobic aprotic solvent with agitation. This is followed by a rinse and spray of the components with a hydrophilic, essentially water soluble solvent, with agitation. The components are then immersed in a water bath and then rinsed with a pressurized spray of water and then dried with a N blow dry.

Method of removing silicone polymer deposits from electronic components

This invention provides a method for removing flux residue and similar other residues formed on the surfaces of micro electronic components during soldering operations using solder paste and fluxing agents in electronic module assembly component fabrication by a semi-aqueous solvent cleaning process using propylene glycol alkyl ether solvents, preferably the mono alkyl ethers, as replacements for xylene. The electronic components may contain plastic components, for example, a plastic grid array (PBGA) in addition to silicon device chip(s), C4 decaps and SMTs on a ceramic chip carrier with solder columns. Preferred solvents are dipropylene glycol mono methyl ether and tripropylene glycol mono methyl ether, which are both water soluble.

Cleaning method to remove flux residue in electronic assembly

Chips requiring high temperature reflow for attachment to a module substrate are attached first and then a eutectic water soluble solder paste and/or water soluble flux is dispensed on both the TSOP and the PBGA chip pads instead of using the paste screening techniques. The dispensing is done by injecting solder on the solder sites individually. Characteristics of the solder paste used is that it must be fluid enough to be injected onto the individual sites yet have enough body that it remains in place and does not run from site to site once dispensed. A paste capable of providing such characteristics is one having: a ) a very fine particle size in the range of 400 to 500 mesh and preferably between 400 and 450 mesh; b) a low viscosity (below 500 k centerpoise and preferably between 425 to 375 cps); and c) a solid content of 86% or lower and preferably between 84 and 80%. The chips to be joined to the module using low temperature module joining are then placed on the module substrate surface and then put in an oven for reflow to attach these chips to the surface. After the joining process, the modules are cleaned by spraying deionized water on them to remove any flux or solder residues and the modules are electrically tested to determine if the joining process has resulted in connection with the proper mechanical and electrical characteristics.

Assembly of multi-chip modules using eutectic solders

A system for testing every one of the signal inputs and outputs (I/O) of a fine pitch multi-chip semiconductor module utilizing a selective netlist, through the intermediary of presently available test equipment. More particularly, the system facilitates the testing of fine pitch multi-chip modules utilizing 1.0 mm ceramic column grid array (CCGA) technology in order to facilitate the use of increased system interconnect capabilities. Additionally, there is provided a method of employing a selective netlist in order to test fine pitch multi-chip semiconductor modules; especially such as, but not limited to 1.0 mm pitch ceramic column grid array (CCGA) modules by employing commercially available test equipment.

Selective netlist to test fine pitch multi-chip semiconductor

A method for joining a multiplicity of multi-alloy solder columns to an electronic substrate and the structure formed by such method are disclosed. In the method, a mold plate equipped with a multiplicity of cavities is first filled by an injection molded solder technique with a high temperature solder forming a multiplicity of solder columns. The mold plate is then sandwiched between an extraction plate and a transfer plate by utilizing a multiplicity of displacement means equipped in the extraction plate to displace the multiplicity of solder columns from the mold plate into a multiplicity of apertures equipped in the transfer plate. The multiplicity of cavities in the transfer plate each has a straight opening and a flared opening. The flared opening is then filled with a low temperature solder paste to encapsulate one end of the high temperature solder column. The low temperature solder paste is then reflown on top of a conductive pad on an electronic substrate at a temperature lower than the melting temperature of the high temperature solder to form a bond between the solder column and the conductive pad.

Low temperature solder column attach by injection molded solder and structure formed

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.

Plastic solder array using injection molded solder

A non-destructive method for identifying off-composition solder columns of for example, a ceramic column grid array. The method is performed at the ceramic module level prior to card assembly to avoid costly loss or rework post card assembly. The assembly of solder columns on a substrate is heated to a temperature below the melting temperature of pure-composition solder and above the temperature of attachment of a solder column to an organic board. Heating the assembly produces visually detectable changes characteristic of off-composition solder which are used for identifying which solder columns are composed of off-composition solder.

Growing community of inventors

Poughkeepsie, NY, United States of America

Chon Cheong Lei