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Printed circuit board using paste bump and manufacturing method thereofRelated Patent Categories: Electricity: Conductors And Insulators, Conduits, Cables Or Conductors, Preformed Panel Circuit Arrangement (e.g., Printed Circuit), With Particular Conductive Connection (e.g., Crossover), FeedthroughPrinted circuit board using paste bump and manufacturing method thereof description/claimsThe Patent Description & Claims data below is from USPTO Patent Application 20070107934, Printed circuit board using paste bump and manufacturing method thereof. Brief Patent Description - Full Patent Description - Patent Application Claims
CROSS-REFERENCE TO RELATED APPLICATIONS [0001] This application claims the benefit of Korean Patent Application No. 2005-0109850, filed with the Korean Intellectual Property Office on Nov. 16, 2005, and Korean Patent Application No. 2005-0109855 filed on Nov. 16, 2005, the disclosures of which are incorporated herein by reference in their entirety. BACKGROUND [0002] 1. Technical Field [0003] The present invention relates to a printed circuit board, and in particular, to a printed circuit board using paste bumps and a manufacturing method thereof. [0004] 2. Description of the Related Art [0005] The conventional multilayer printed circuit board is manufactured by forming inner layer circuits on the surface of a core board, such as a copper clad laminate (CCL), etc., through the application of an additive process or a subtractive process, etc., and by forming outer layer circuits through the stacking of insulation layers and metal layers in order, by the same method as for the inner layer circuits. [0006] During the manufacturing process of a multilayer printed circuit board, various via holes are formed, such as IVH's (interstitial via holes), BVH's (blind via holes), and PTH's (plated through holes), etc., for electrical connection between the circuit patterns of each layer and between a circuit pattern and an electronic element. Among these, the PTH's, which are formed penetrating the entire thickness in the cross section of a board, also function as heat-releasing holes, in addition to the function of electrical connection mentioned above. [0007] With developments in electronic components, there is a demand for technology which can improve the performance of HDI (high density interconnection) boards, to which the concepts of interlayer electrical connection and micro circuit wiring have been applied for higher density printed circuit boards. That is, to improve the performance of HDI boards, a technology is required which provides interlayer electrical connection and an adequate degree of freedom. [0008] The method of manufacturing a multilayer printed circuit board according to prior art includes first perforating via holes (e.g. IVR's, etc.) in a core board (e.g. a CCL, etc.) by mechanical drilling, etc., forming plating layers (e.g. by chemical copper plating and/or copper electroplating, etc.) on the surfaces of the core board and on the inner perimeters of the via holes, filling the inside spaces of the IVH's and polishing the surfaces, and then forming inner layer circuits on the surfaces of the core board by applying an additive or a subtractive process, etc., and inspecting the circuits. Next, a build-up process is performed by procedures of surface treatment and stacking RCC (resin coated copper), etc., and via holes are formed for interlayer electrical connection between circuit patterns by laser drilling, etc., after which outer layer circuits are formed on the surface of the stacked board and the circuits are inspected. To add more layers of circuit patterns, the process is repeated of surface treatment and stacking RCC, etc., forming via holes, plating the surfaces of the via holes, and afterwards forming outer layer circuits. Such a build-up process is repeated to form a desired number of circuit pattern layers. [0009] That is, metal layers are formed after stacking insulation material, or insulation material that has a metal layer formed on its surface (e.g. RCC, etc.) is stacked, on the surfaces of a core board, after which BVH's are processed by laser drilling, etc., for electrical connection between metal layers and inner layer circuits, PTH's which penetrate the entire cross section of the printed circuit board are perforated by mechanical drilling, etc., outer layer circuit layers are formed on the surfaces of the insulation material by the same method as for the inner layer circuits, and the inner perimeters of the PTH's are plated so that the PTH's function as heat-releasing holes. [0010] However, the conventional manufacturing process for multilayer printed circuit boards is unable to comply to requests for low costs according to lowering prices in the applied products (e.g. cell phones, etc.) and requests for reduced lead times for increased productivity, and thus there is a demand for a new manufacturing process that can resolve such problems. [0011] Also, the conventional method requires a plating process which is complicated, expensive, and time-consuming, and does not provide a sufficient heat-releasing effect through the PTH's. Also, when forming circuit patterns after forming the plating layer, the conventional method presents difficulties in forming micro circuits, caused by the increase in thickness of the circuit patterns due to the plating layer. [0012] Meanwhile, in order to simplify the complicated process of prior art and to manufacture a multilayer printed circuit quickly and inexpensively by a collective stacking procedure, the so-called "B2IT (buried bump interconnection technology)" has been commercialized, which allows a simple and convenient stacking process by printing paste on a copper foil 3 to form bumps 2' and stacking an insulation material 1 thereon to prefabricate a paste bump board, as illustrated in FIG. 1. [0013] Prior art related to the paste bump board includes an invention which uses a paste bump board having bumps made of conductive paste formed on a copper foil to allow simple and easy interconnection between the terminals of high-density electronic components. This invention, however, implements all-layer IVH's with only the paste bump board so that it has a weak structure. Also, there is a likelihood of short circuits occurring in a high-voltage, high-frequency environment, and there are paste bumps filled in the board's via holes so that the properties of heat release through PTH's have not been improved. SUMMARY [0014] The present invention aims to provide a printed circuit board and a manufacturing method thereof, with which a multilayer printed circuit board is formed by collectively stacking a core board having plated BVH's, a board having paste bumps printed on a core board, and a paste bump board, to implement a structurally stable all-layer IVH structure, improve the connection reliability by means of an increase in interlayer connection area, and reduce lead times. Another object of the present invention is to provide a printed circuit board using paste bumps and a manufacturing method thereof, for which paste bump boards are stacked on a core board and paste bumps are filled in heat-releasing holes, such that the heat-releasing effect is improved. [0015] One aspect of the present invention provides a method of manufacturing a printed circuit board using paste bumps, comprising: (a) perforating a core board to form at least one via hole, (b) filling the at least one via hole by fill-plating and forming a circuit pattern on at least one surface of the core board, (c) stacking a paste bump board on at least one surface of the core board, and (d) forming an outer layer circuit on a surface of the paste bump board. [0016] It may be preferable that the core board be a copper clad laminate (CCL), which has a copper foil layer stacked on its surface. In certain embodiments, the method may further include an operation of removing the copper foil layer in correspondence with a position where the at least one via hole is to be formed, before the operation (a) of perforating a core board to form at least one via hole. The method may also-further include an operation of reducing the thickness of the copper foil layer by half-etching, between the operation (a) of perforating a core board to form at least one via hole and the operation (b) of filling the at least one via hole by fill-plating and forming a circuit pattern on at least one surface of the core board. The via hole may preferably be a blind via hole (BVH). [0017] Preferably, the paste bump board may be formed by (e) printing at least one paste bump on a copper foil, (f) setting the at least one paste bump, and (g) stacking an insulation material on the copper foil such that the at least one paste bump penetrates the insulation material. [0018] A plating layer, formed by the fill-plating in the at least one via hole, may preferably comprise a dimple, with the at least one paste bump formed in correspondence with a position of the dimple. The strength of the paste bump may preferably be lower than that of the plating layer and greater than that of the insulation material. The paste bump may include silver paste. [0019] In certain embodiments, the method may further include an operation of pressing the paste bump board onto the core board, between the operation (c) of stacking a paste bump board on at least one surface of the core board and the operation (d) of forming an outer layer circuit on a surface of the paste bump board. [0020] Another aspect of the invention provides a method of manufacturing a printed circuit board using paste bumps by collectively stacking at least one first core board, at least one second core board, and at least one outer layer board, in which the first core board is formed by (a) forming at least one BVH (blind via hole) on one surface of a core member, and (b) filling the at least one BVH by fill-plating and forming a circuit pattern on at least one surface of the core member; the second core board is formed by (c) joining at least one core bump onto the other surface of the core member of the first core board in a position where the at least one BVH is formed, (d) setting the at least one core bump, and (e) stacking a core insulation material on the other surface of the core member such that the at least one core bump penetrates the core insulation material; while the outer layer board is formed by (f) joining at least one outer layer bump onto a copper foil, (g) setting the at least one outer layer bump, and (h) stacking an outer layer insulation material on the copper foil such that the at least one outer layer bump penetrates the outer layer insulation material. [0021] The core member may preferably be a copper clad laminate (CCL), which has a copper foil layer stacked on its surface. In certain embodiments, the method may further include an operation of removing the copper foil layer in correspondence with a position where the BVH is to be formed, before the operation (a) of forming at least one BVH on one surface of a core member. The method may also further include an operation of reducing the thickness of the copper foil layer by half-etching, between the operation (a) of forming at least one BVH on one surface of a core member and the operation (b) of filling the at least one BVH by fill-plating and forming a circuit pattern on at least one surface of the core member. Continue reading about Printed circuit board using paste bump and manufacturing method thereof... 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Start now! - Receive info on patent apps like Printed circuit board using paste bump and manufacturing method thereof or other areas of interest. ### Previous Patent Application: Internal conductor connection structure and multilayer substrate Next Patent Application: Method and apparatus for electrically connecting printed circuit boards or other panels Industry Class: Electricity: conductors and insulators ### FreshPatents.com Support Thank you for viewing the Printed circuit board using paste bump and manufacturing method thereof patent info. IP-related news and info Results in 0.1326 seconds Other interesting Feshpatents.com categories: Computers: Graphics , I/O , Processors , Dyn. Storage , Static Storage , Printers 174 |
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