Endicott Interconnect Technologies, Inc.

International Business Machines Corporation

Norman A Card

John Joseph Konrad

Richard Allen Day

Timothy Leroy Wells

James D Herard

Der-jin Woan

James M Ergler

Paul R Kasperek

Richard S McKinley

John M Lauffer

David John Russell

Thomas R Miller

Roy H Magnuson

William John Rudik

Ashwinkumar C Bhatt

Michael Wozniak

Donald Herman Glatzel

Stephen Joseph Fuerniss

Jeffrey McKeveny

Robert Douglas Edwards

Lawrence Robert Blumberg

Jose A Rios

Robert J Harendza

Tonya L Mosher

Charles Buchter

Susan Pitely

A method of forming a buried resistor within a cavity for use in electronic packages using two glass impregnated dielectric layers, one with a clearance hole, the second with a resistor core, the clearance hole being placed over the resistor core and the assembly fusion bonded. The space remaining around the resistor core is filled with a soldermask material and the assembly is coated with metal. Thru-holes are drilled, cleaned, and plated and then the metal coating is etched and partially removed. The soldermask is then removed and a layer of gold plating is applied to the exposed metal surfaces. The use of glass impregnated dielectric layers and fusion bonding eliminates the fluorinated ethylene propylene resin (FEP) bleed problem associated with previous buried resistor cavity assemblies.

Method of cavity forming on a buried resistor layer using a fusion bonding process

A method of making a circuitized substrate in which the substrate includes circuit elements having exposed surfaces defined by two thin layers of permanent photoimaged solder mask material which are applied through fine mesh screens. The use of two thin layers assures effective coverage of the material to precisely expose the desired surfaces in high-density circuit patterns. A circuitized substrate assembly and an information handling system adapted for having one or more such assemblies therein are also provided.

Circuitized substrate assembly

A method of making a circuitized substrate in which conductors are formed in such a manner that selected ones of the conductors include solder while others do not and are thus adapted for receiving a different form of connection (e.g., wire-bond) than the solder covered conductors. In one embodiment, the solder may be applied in molten form by immersing the substrate within a bath of the solder while in another the solder may be deposited using a screening procedure.

Method of making circuitized substrate with selected conductors having solder thereon

A method of making a circuitized substrate assembly in which two or more subassemblies are aligned and bonded together. The bonding, preferably using lamination, results in effective electrical connections being formed between respective pairs of conductors of the subassemblies in such a manner that the metallurgies of the conductors, and those of an interim metallic solder paste, are effectively mixed and the flowable interim dielectric used between the mating subassemblies is forced to flow to engage and surround the conductor coupling, without adversely affecting the electrical connection formed.

Method of making circuitized substrate with solder paste connections

A method and apparatus for depositing conductive paste in openings of a circuitized substrate such as a multilayered printed circuit board to produce effective conductive thru-holes capable of being electrically coupled to selected conductive layers of the substrate. The invention comprises using vacuum to draw from the underside of the substrate while substantially simultaneously applying the paste onto the substrate's opposing surface. One example of means for accomplishing such paste application is a squeegee, and in one embodiment, two such squeegees may be used. A porous member is used to engage the substrate's undersurface during the vacuum draw, this member being positioned atop a base vacuum member through which the vacuum is drawn.

Method and apparatus for depositing conductive paste in circuitized substrate openings

A method of plating a circuit pattern on a substrate to produce a circuitized substrate (e.g., a printed circuit board) in which a dual step metallurgy application process is used in combination with a dual step photo-resist removal process. Thru-holes are also possible, albeit not required.

Plating method for circuitized substrates

Through-holes in a substrate are masked during plating of the substrate by substantially filling the through-holes with a liquid material, followed by applying a photoimageable material to an external surface of the substrate, forming a predetermined pattern in the photoimageable material, circuitizing the predetermined pattern and then removing both the photoimageable material and the liquid material from the through-holes.

Method for masking a hole in a substrate during plating

A method and apparatus is described for reworking a printed circuit board having plugged vias and plated through holes. The printed circuit board, supported by a movable local support, is heated from only the bottom side by a heating device near the area on the PCB that contains the plated through hole or holes to be reworked. The heating device is removed when the solder in the plugged PTH is completely melted. At that time, blast air is turned on to remove and blow off the excess solder in the PTH. The compressed air is more effective in displacing the molten solder than is vacuuming, and has less chance of damaging the PCB than do conventional reworking methods, due to the non-contact nature of the invention.

Process for reworking circuit boards

Machine and process for reworking circuit boards

An improved photoimagable cationically polymerizable epoxy based coating material is provided. The material includes an epoxy resin system consisting essentially of between about 10% and about 80% by weight of a polyol resin which is a condensation product of epichlorohydrin and bisphenol A having a molecular weight of between about 40,000 and 130,000; between about 20% and about 90% by weight of an epoxidized octafunctional bisphenol A formaldehyde novolak resin having a molecular weight of 4,000 to 10,000; and if flame retardancy is required between about 35% and 50% by weight of an epoxidized glycidyl ether of tetrabromo bisphenol A having a softening point of between about 60 C. and about 110 C. and a molecular weight of between about 600 and 2,500. To this resin system is added about 0.1 to about 15 parts by weight per 100 parts of resin of a cationic photoinitiator capable of initiating polymerization of said epoxidized resin system upon exposure to actinic radiation; the system being further characterized by having an absorbance of light in the 330 to 700 nm region of less than 0.1 for a 2.0 mil thick film, and an effective amount of thixatropic agent. Optionally a photosensitizer such as perylene and its derivatives or anthracene and its derivatives may be added.

Composition for photo imaging

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Lockwood, NY, United States of America

Norman A Card