摘要:
The present invention provides new methods for electroless plating of metal particularly gold and copper onto substrates, such as circuitized substrates, which reduces processing steps, reduces metal consumption, and reduces the scraping of parts due to contamination. The method employs a permanent plating resist. The method for electrolessly plating metal onto a substrate, including the following steps: providing: an uncured, photoimagable, dielectric permanent plating resist comprising: from about 10 to 80% of phenoxy polyol resin which is the condensation product of epichlorohydrin and bisphenol A, having a molecular weight of from about 40,000 to 130,000; from about 20 to 90% of an epoxidized multifunctional bisphenol A formaldehyde novolac resin having a molecular weight of from about 4,000 to 10,000; from 0 to 50% of a diglycidyl ether of bisphenol A having a molecular weight of from about 600 to 2,500; and from about 0.1 to 15 parts by weight of the total resin weight, a cationic photoinitiator; applying the permanent plating resist on the substrate; photopatterning the permanent plating resist to form apertures therein which expose areas of the substrate; and electrolessly plating metal onto the exposed areas of the substrate. The permanent plating resist is useful to protect the substrate areas including for example metallized features on the substrate, from the electroless deposition of metal during electroless plating; thus selective plating of metal is achieved. The permanent plating resist is not degraded by conventional gold or copper electroless baths. The invention also relates to circuitized structures produced by the methods of electroless plating.
摘要:
A circuit assembly that includes a circuitized substrate having a dielectric interior layer with a first surface and at least one hole therein. A filler material substantially fills the hole within the dielectric interior layer. A first wiring layer is positioned on the first surface of the dielectric interior layer, wherein the first wiring layer substantially covers the hole and assists in retaining the filler material within the hole in the dielectric interior layer. A first dielectric photoresist layer is positioned on the first wiring layer and on the first surface of the dielectric interior layer. The first dielectric photoresist layer also includes at least one hole therein. The filler material also substantially fills the hole within the first dielectric photoresist layer. A second wiring layer is positioned on the first dielectric photoresist layer and includes a plurality of conductive pads as part thereof. At least one external component can be electrically coupled to the conductive pads of the second wiring layer.
摘要:
A process for manufacturing circuit boards comprising providing a circuitized substrate having a dielectric surface, providing a peel apart structure including a metal layer and a peelable film, laminating the peel apart structure to the circuitized substrate with the metal layer positioned adjacent said dielectric surface, forming holes in the circuitized substrate through the peel apart structure, applying a filler material including an organic base to the peel apart structure, applying a sacrificial film onto the filler material, and applying sufficient heat and pressure to the sacrificial film to force the filler material into the holes to substantially fill the holes is provided.
摘要:
An information handling system is provided which comprises: a metal enclosure; at least one circuit assembly positioned within said metal enclosure, said circuit assembly including a circuitized substrate having at least one dielectric interior layer including a first surface and at least one hole therein; means for providing electrical power to said circuitized substrate within said metal enclosure; a filler material, wherein said filler material substantially fills said at least one hole within said at least one dielectric interior layer; a first wiring layer positioned on said first surface of said at least one dielectric interior layer, wherein said first wiring layer substantially covers said at least one hole having said filler material therein, said first wiring layer assisting in retaining said filler material within said at least one hole in said at least one dielectric interior layer; a first dielectric photoresist layer positioned on said first wiring layer and on said first surface of said at least one dielectric interior layer, wherein said first dielectric photoresist layer also includes at least one hole therein, said filler material also substantially filling said at least one hole within said first dielectric photoresist layer; a second wiring layer positioned on said first dielectric photoresist layer; wherein said second wiring layer includes a plurality of conductive pads as part thereof; and at least one external component electrically coupled to said conductive pads of said second wiring layer.
摘要:
Circuit boards are manufactured by forming a substrate with a dielectric surface, laminating a metal foil and a peelable film to the substrate, and forming holes in the substrate through the peelable film and foil. A filler material with an organic base may be filled with electroconductive particles or dielectric thermoconductive particles. The filler material is deposited onto a sacrificial carrier and the filler material is heated to at least partially cure it. The filler material is laminated onto the peelable film with sufficient heat and pressure to force the filler material to fill the holes. For thermoconductive filler the holes are filled sufficient for electrical connection through the holes. The peelable layer, sacrificial carrier and filler material remaining therebetween are peeled off the copper foil. The filler material is abraded to the level of the foil and is then copper plated. The copper is patterned to form a wiring layer. A permanent dielectric photoresist layer is formed over the wiring layer and via holes are formed through the photoimagable dielectric over pads and conductors of the wiring layer. Holes are formed through the substrate and the photoimagable dielectric, walls of the via holes, and walls of the through holes are copper plated. The copper plating on the photoimagable dielectric is patterned to form an exterior wiring layer which is covered by solder resist with windows over lands around the through holes and surface mount connection pads of the exterior wiring layer to form a high density circuitized substrate. Surface mount components and/or pin in hole components are attached to the circuitized substrate with solder joints between terminals of the components and the lands and/or connection pads to form a high density circuit board assembly. One or more of the circuit board assemblies are mounted in an enclosure with a power supply, CPU, RAM, and I/O means to form an improved information handling system with increased performance due to shorter signal flight times due to the high component density.
摘要:
Circuit boards are manufactured by forming a substrate with a dielectric surface, laminating a metal foil to the substrate, and forming holes in the substrate through the foil. A filler material with an organic base may be filled with electroconductive particles or dielectric thermoconductive particles. The filler material is deposited into the holes and is heated to at least partially cure it. The surface of the filler material is seeded and electrolessly plated to form a conductive coating on the metal foil and the filler material. The coating is then patterned to form a wiring layer. A second set of holes may be formed in the circuitized substrate after the hole filling step, which are also electrolessly plated.
摘要:
A modular structure for providing electrical interconnections achieves greatly increased wiring density by forming vias and wiring patterns by chemical (e.g. lithographic) processes rather than by mechanical processes such as punching of vias and screening patterns of conductive paste. A basic module is a power core comprising an apertured metallic foil with an insulator applied to surfaces thereof, extending through at least one aperture and exposing the metallic foil in at least one aperture. The foil in the power core provides stiffness to facilitate subsequent handling and electrical shielding between conductive layers as well as a potential power connection. Via connections of increased conductivity and robustness are formed by plating the interior of vias after lamination of a desired combination of power cores and signal cores. Vias remain unfilled until after lamination and are available to facilitate optical alignment of composite layers including signal cores, power cores and laminated combinations thereof.
摘要:
Circuit boards are manufactured by forming a substrate with a dielectric surface, laminating a metal foil and a peelable film to the substrate, and forming holes in the substrate through the peelable film and foil. A filler material with an organic base may be filled with electroconductive particles or dielectric thermoconductive particles. The filler material is laminated onto the peelable film with sufficient heat and pressure to force the filler material to fill the holes. For thermoconductive filler the holes are filled sufficient for electrical connection through the holes. The filler material is abraded to the level of the foil and is then copper plated. The copper is patterned to form a wiring layer. A permanent dielectric photoresist layer is formed over the wiring layer and via holes are formed through the photoimageable dielectric over pads and conductors of the wiring layer. Holes are formed through the substrate and the photoimageable dielectric, walls of the via holes, and walls of the through holes are copper plated. The copper plating on the photoimageable dielectric is patterned of form an exterior wiring layer. Components and/or pins are attached to the surface of the circuitized substrate with solder joints to form a high density circuit board assembly.
摘要:
A novel process for circuitizing a dielectric layer, particularly for adding wiring planes, which is employed in the fabrication of circuitized structures, that does not requiring drilling of vias, yet provides good adhesion of circuitization to dielectric layer. In its broadest sense the method comprises the following steps: a. providing: a substrate; a hydrophobic, uncured, photoimagable, dielectric film having a solvent content of from about 5 to 30%; metal foil; b. contacting the metal foil and the dielectric film so that a replicate image is formed in the dielectric film; c. disposing the dielectric film on the substrate either after step a or step b; d. etching the metal foil from the dielectric film after step c; e. after step d, photoimaging the dielectric film to form vias or through holes in the dielectric film; and then metallizing the film after step e, to provide circuitization atop the dielectric film. The invention also relates to the circuitized structures produce by the method.
摘要:
A metal carrier has a dielectric material with a thickness of less than 0.004 inch and electrical voltage insulation characteristics of at least 2500 volts formed on a surface. A donut configured land defines at least one via or opening for removing dielectric material selectively. Reflow solder is used to form electrical interconnections, and the vias provide thermal dissipation sufficient to conform to safety requirements.