| Method of making printed circuit board with varying depth conductive holes adapted for receiving pinned electrical components -> Monitor Keywords |
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Method of making printed circuit board with varying depth conductive holes adapted for receiving pinned electrical componentsRelated Patent Categories: Semiconductor Device Manufacturing: Process, Coating With Electrically Or Thermally Conductive Material, To Form Ohmic Contact To Semiconductive Material, Contacting Multiple Semiconductive Regions (i.e., Interconnects), Multiple Metal Levels, Separated By Insulating Layer (i.e., Multiple Level Metallization)Method of making printed circuit board with varying depth conductive holes adapted for receiving pinned electrical components description/claimsThe Patent Description & Claims data below is from USPTO Patent Application 20060121722, Method of making printed circuit board with varying depth conductive holes adapted for receiving pinned electrical components. Brief Patent Description - Full Patent Description - Patent Application Claims
CROSS REFERENCE TO CO-PENDING APPLICATION [0001] In application Ser. No. 10/737,974, filed Dec. 18, 2003 and entitled "METHOD OF PROVIDING PRINTED CIRCUIT BOARD WITH CONDUCTIVE HOLES AND BOARD RESULTING THEREFROM" (Inventors: J. Larnerd et al), there is defined a method of making a printed circuit board in which conductive thru-holes are formed within two dielectric layers of the board's structure so as to connect designated conductive layers. One hole connects two adjacent conductive layers and the other also connects two adjacent conductive layers, including one of the conductive layers connected by the other hole. It is also possible to connect all three conductive layers using one or more holes. The resulting holes may be filled, e.g., with metal plating, or conductive or non-conductive paste. In the case of the latter, it is also possible to provide a top covering conductive layer over the paste, e.g., to serve as a pad or the like on the board's external surface. Application Ser. No. 10/737,974 is assigned to the same Assignee as the present invention. [0002] This application is a continuation-in-part application of Ser. No. 10/737,974. [0003] In Ser. No. 10/955,741, filed Sep. 30, 2004 and entitled "HIGH SPEED CIRCUITIZED SUBSTRATE WITH REDUCED THRU-HOLE STUB, METHOD FOR FABRICATION AND INFORMATION HANDLING SYSTEM UTILIZING SAME" (Inventors: B. Chan et al), there is defined a circuitized substrate including a plurality of conductive and dielectric layers and also a plurality of conductive thru-holes therein for passing high speed signals, e.g., from one component to another mounted on the substrate. The substrate utilizes a signal routing pattern which uses the maximum length of each of the thru-holes wherever possible to thereby substantially eliminate signal loss (noise) due to thru-hole "stub" resonance. [0004] In application Ser. No. 10/811,817, filed Mar. 30, 2004 and entitled "HIGH SPEED CIRCUIT BOARD AND METHOD FOR FABRICATION" (Inventors: B. Chan et al), there is defined a multilayered PCB including two multilayered portions, one of these able to electrically connect electronic components mounted on the PCB to assure high frequency connections there-between. The PCB further includes a conventional PCB portion to reduce costs while assuring a structure having a satisfactory overall thickness for use in the PCB field. Coupling is also possible to the internal portion from these components. [0005] All of the above applications are assigned to the same Assignee as the present invention. TECHNICAL FIELD [0006] This invention relates to printed circuit (or wiring) boards and particularly to multilayered printed circuit boards having a plurality of conductive holes therein. Even more particularly, the invention relates to such boards which are adapted for having one or more electrical connectors positioned thereon and electrically coupled thereto. BACKGROUND OF THE INVENTION [0007] As indicated from the following listing of patents, there are different methods of making multilayered printed circuit boards (hereinafter also referred to as PCBs) known today. In the manufacture of some printed circuit boards, for example, it has become commonplace to produce printed circuitry on both sides of a planar rigid or flexible insulating substrate. In addition, such boards also typically include several parallel and planar, alternating inner layers of insulating substrate material and conductive metal. The exposed outer sides of the laminated structure are typically provided with circuit patterns, and the metal inner layers typically contain circuit patterns, except in the case of internal power or ground planes which are usually substantially solid, albeit also containing clearance openings or other openings if desired. [0008] In multilayered printed circuit boards such as these, it is necessary to provide conductive interconnections between the various conductive layers or sides of the board. This is commonly achieved by providing metallized conductive holes in the board which communicate with the sides and layers requiring electrical interconnection. For some applications, it is desired that electrical connection be made with almost if not all of the conductive layers. In such a case, conductive holes are also typically provided through the entire thickness of the board. For these, as well as other applications, it is often desired to also provide electrical connection between the circuitry on one face of the board and one or more of the inner circuit layers. In those cases, holes referred to as "blind vias", passing only part way through the board, are provided. In still another case, such multilayered boards often require internal holes referred to simply as "vias" which are located entirely within the board's structure and covered by external layering, including both dielectric and conductive. Such internal "vias" are typically formed within a sub-part structure (sub-composite) of the final board and then combined with other layers (including other sub-composites) during final lamination of the board. For purposes of this application, the term "thru-hole" is meant to include conductive holes that pass entirely through the board (also referred to in the printed circuit field as plated thru holes or PTHs), "blind vias" which extend from an external surface of the board into a specified conductive layer of the board, as well as an "internal via" which is internal "captured" by the board's outer layers. [0009] To provide the desired circuit pattern on the board, the art has developed a variety of manufacturing sequences, many of which fall into the broad categories of "subtractive" or "additive" techniques. Common to subtractive processes is the need to etch away (or subtract) metal to expose substrate surface in areas where no circuitry is desired. Additive processes, on the other hand, begin with exposed substrate surfaces (or thin commoning metallization layers for additive electroplate) and build up thereon of metallization in desired areas, the desired areas being those not masked by a previously-applied pattern of plating resist material (e.g., called photo-resist in the printed circuit board field). [0010] Typically, thru-holes are drilled (including mechanically or more recently using lasers) or punched into or through the board at desired locations. Drilling or punching provides newly-exposed surfaces including via barrel surfaces and via peripheral entry surfaces. The dielectric substrate, comprising a top surface, a bottom surface, and at least one exposed via hole surface, consisting partly or entirely of insulating material, is then metallized, generally by utilization of electro-less metal depositing techniques, albeit other deposition processes are also known in the field. [0011] In the manufacture of circuitized printed circuit boards, a dielectric sheet material is typically employed as the base component for the substrate. This base component is usually comprised of an organic material, such as fiberglass-reinforced epoxy resin (also referred to in the field as, simply, "FR4"), polytetrafluoroethylene (e.g., Teflon, a trademark of E.I. duPont deNemours & Company), Driclad dielectric material (Driclad being a trademark of Endicott Interconnect Technologies, Inc.), etc. Since the dielectric substrate is nonconductive, in order to plate on the substrate, the substrate is typically "seeded" and plating then occurs. Such processing is known in the field and further description is not believed necessary, except to add that known metals used for plating the dielectric barrel to form the thru holes include copper, nickel and gold. [0012] Examples of methods of making boards, including providing same with such thru holes, are shown and described in the following U.S. Letters Patents: TABLE-US-00001 6,015,520 Method For Filling Holes in Printed Wiring Boards 6,073,344 Laser Segmentation of Plated Through-Hole Sidewalls To Form Multiple Conductors 6,188,027 Protection of a Plated Through Hole From Chemical Attack 6,281,446 Multi-Layered Circuit Board And Method of Manufacturing The Same 6,349,871 Process For Reworking Circuit Boards 6,493,861 Interconnected Series of Plated Through Hole Vias and Method of Fabrication Therefore 6,495,772 High Performance Dense Wire For Printed Circuit Board 6,518,516 Multilayered Laminate 6,626,196 Arrangement and Method For Degassing Small-High Aspect Ratio Drilled Holes Prior To Wet Chemical Processing 6,628,531 Multi-Layer and User-Configurable Micro-Printed Circuit Board 6,630,630 Multilayer Printed Wiring Board and Its Manufacturing Method 6,630,743 Copper Plated PTH Barrels and Methods For Fabricating 6,631,558 Blind Via Laser Drilling System 6,631,838 Method For Fabricating Printed Circuit Board 6,638,690 Method For Producing Multi-Layer Circuits 6,638,858 Hole Metal-Filling Method 6,809,269 Circuitized Substrate Assembly And Method Of Making Same 6,832,436 Conductive Substructures Of A Multilayered Laminate 6,872,894 Information Handling System Utilizing Circuitized Substrate [0013] The present invention is able to produce a printed circuit board which is capable of having high speed signals pass through the signal conductors thereof, another highly desirable feature required of many of today's newer boards. By the term "high speed" is of course also meant to mean high frequency. Further description is provided below. [0014] The present invention represents a new and unique method of forming conductive thru holes in a printed circuit board in comparison to those above and other processes known in the art. It is believed that such a method, and the board resulting there-from, will represent a significant advancement in the art. DESCRIPTION OF THE INVENTION [0015] It is, therefore, a primary object of the present invention to enhance the printed circuit board art by providing a new and unique method of producing such boards. [0016] It is another object of the invention to provide such a process and resulting board in which several conductive thru holes are formed to interconnect various conductive layers of the board in a new and expeditious manner. [0017] It is still another object of the invention to provide such a process which can be implemented using conventional printed circuit board technologies and thus performed with little or no increased cost over conventional techniques. [0018] According to one aspect of the invention, there is provided a method of making a multilayered printed circuit board (PCB), the method comprising providing a first sub-composite including at least one dielectric layer and at least one opening therein having first and second opposing open end portions and extending substantially through the at least one dielectric layer, positioning a cover on the first opposing open end portion of the at least one opening, aligning the first sub-composite having the at least one opening therein having the cover on the first opposing open end portion with a second sub-composite including at least one dielectric layer such that the cover faces the second sub-composite, positioning a layer of heat-deformable dielectric material between the first and second sub-composites, and bonding the first and second sub-composites and layer dielectric material together using heat and/or pressure sufficient to deform the layer of heat-deformable material, the cover on the at least one opening preventing the dielectric material of the layer of heat-deformable dielectric material from entering the opening. BRIEF DESCRIPTION OF THE DRAWINGS [0019] FIGS. 1-5 illustrate the steps of making a PCB according to one aspect of the invention, each of these FIGS being an elevational view, in section; Continue reading about Method of making printed circuit board with varying depth conductive holes adapted for receiving pinned electrical components... Full patent description for Method of making printed circuit board with varying depth conductive holes adapted for receiving pinned electrical components Brief Patent Description - Full Patent Description - Patent Application Claims Click on the above for other options relating to this Method of making printed circuit board with varying depth conductive holes adapted for receiving pinned electrical components patent application. ###  How KEYWORD MONITOR works... a FREE service from FreshPatents1. Sign up (takes 30 seconds). 2. Fill in the keywords to be monitored. 3. Each week you receive an email with patent applications related to your keywords. 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