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Interconnection element for bga housings and method for producing the sameRelated Patent Categories: Electrical Connectors, Preformed Panel Circuit Arrangement, E.g., Pcb, Icm, Dip, Chip, Wafer, Etc., With Provision To Conduct Electricity From Panel Circuit To Another Panel Circuit, Conductor Is Compressible And To Be Sandwiched Between Panel CircuitsInterconnection element for bga housings and method for producing the same description/claimsThe Patent Description & Claims data below is from USPTO Patent Application 20070123066, Interconnection element for bga housings and method for producing the same. Brief Patent Description - Full Patent Description - Patent Application Claims
[0001] This application is a divisional of patent application serial number 10/944,684, entitled "Interconnection Element for BGA Housings and Method for Producing the Same," filed on Sep. 17, 2004, which claims priority to German Patent Application 103 43 255.8, which was filed Sep. 17, 2003, both of which are incorporated herein by reference. TECHNICAL FIELD [0002] The invention relates to an interconnection element for BGA housings and comparable housings having an interposer substrate. BACKGROUND [0003] In accordance with the customary prior art for FPBGA housings (FPBGA: Fine Pitch Ball Grid Array), caBGA housings (caBGA: Chip Array Ball Grid Array) or TFBGA housings (TFBGA: Thin Fine Pitch Ball Grid Array Package), the packages are provided with an interposer substrate, for example made of a bismaleimide triazine resin. The BGA housings are characterized by the fact that component terminals are applied on their underside area in the form of solder balls. [0004] The solder balls are applied by means of a so-called ball placement. During this method, the solder balls are introduced into a flux in the envisaged contact locations in the form of a ball grid array situated on the interposer. In its conventional form, this ball placement is very complicated and very demanding in terms of process engineering. [0005] The conventional ball placement for an FPBGA package construction is characterized by the fact that firstly a water-soluble, rosin-containing flux is applied to the interposer substrate. This flux has the task of breaking up the oxide layers on the conductive tracks on the interposer substrate and on the solder balls and of making the surfaces wettable. The solder balls placed into the flux are subsequently held at the introduction location by adhesion forces. [0006] In the subsequent reflow soldering process in a soldering furnace, the solder balls are then fused onto the interposer substrate in a multizone cycle at temperatures of 110.degree. C. to 225.degree. C. In this case, the soldering temperature is dependent on the solder materials used. [0007] In order that the flux residues are removed again after the fusing operation, the interposer is subsequently cleaned, preferably by means of spray washing. [0008] The solder balls mounted on the interposer in this way then have to take up in part considerable shear forces after the mounting of the BGA assembly on a printed circuit board, which arise as a result of the thermally governed different coefficients of expansion of the materials involved. [0009] DE 198 33 131 A1 describes a method for the contact-connection of electronic components on flexible substrates, in which semiconductor chips provided with FBGA contact terminals are pressed in a force-locking or positively-locking manner onto the flexible substrate provided with a corresponding contact structure. Utilizing the elasticity of the flexible substrate for contact production ensures that a reliable contact-connection is affected even when the microballs have small size deviations. [0010] What is disadvantageous in this case is that, on the one hand, the placement of the semiconductor chips has to be effected with high accuracy for lack of floating effects and that, on the other hand, quite large-area contacts with elevated contact resistance arise. [0011] Finally, WO 97/00598 (U.S. Pat. No. 6,321,443) describes a connection substrate comprising a dielectric, in the case of which a real connection structures are provided on both sides. Metallized vias as the connection elements are connected to one another. However, this connection element is not suitable for the contact-connection of BGA housings. SUMMARY OF THE INVENTION [0012] In one aspect, the invention provides an interconnect element for BGA housings that can be produced cost-effectively and can take up thermally governed forces (shear forces) without any problems, and also of specifying a method for producing the same. [0013] In the preferred embodiment, the interconnection element comprises the interposer substrate and a multiplicity of connection elements which are formed in hollow-cylindrical or rod-shaped fashion and are fixedly connected to the interposer substrate, in a manner penetrating through the latter, and also the rewiring. [0014] The interconnection element according to embodiments of the invention can be produced simply, on the one hand, and, on the other hand, enables a substantially simplified mounting technology compared with the solder balls used heretofore. Thus, the interposer substrate not only functions for receiving the rewiring and as a chip-carrying element, but also serves for forming and receiving the new hollow-cylindrical or pin-shaped connection elements that completely replace the solder balls used heretofore. [0015] A further advantage of embodiments of the invention is to be seen in the fact that it is possible to completely prefabricate the interposer substrate with the rewiring and the connection elements embedded in it. [0016] In order that the FBGA package completed by means of chip mounting, wire bonding and molding can be mounted on a printed circuit board, a development of the invention provides for the connection elements to at least partly project from the surface of the interposer substrate. The connection elements may comprise copper or gold and have a diameter of approximately 25 .mu.m. [0017] For the case where the connection elements comprise copper, it is advantageous if they have a surface refinement, e.g., made of nickel and/or gold. [0018] In another aspect, the invention provides a method, which is characterized by the fact that firstly microvias formed in the pitch of ball grid array contact terminals are introduced into an interposer substrate. An electrically conductive material is subsequently introduced into the microvias in a manner forming the connection elements. At the same time, an electrical connection to rewiring of the interposer substrate being produced. A part of the material of the interposer substrate is then removed areally, so that the connection elements protrude from the surface of the interposer substrate. [0019] A further advantage of embodiments of the invention is to be seen in the fact that the electrical connection between the rewiring and the connection elements can be produced in a manner completely free of solder, in contrast to the conventional FBGA technology. At the same time, this also results in a gain in reliability. [0020] In this case, the areal removal (thinning) of the material of the interposer substrate may be effected before or after the chip mounting/molding. It is particularly advantageous if the thinning of the interposer substrate is performed after the chip bonding or before the mounting of the FBGA package on a printed circuit board, because damage to the connection elements during the handling of the package is then virtually precluded. [0021] A development of the invention provides for the microvias to be completely filled with an electrically conductive material, in a manner forming the connection elements. Continue reading about Interconnection element for bga housings and method for producing the same... Full patent description for Interconnection element for bga housings and method for producing the same Brief Patent Description - Full Patent Description - Patent Application Claims Click on the above for other options relating to this Interconnection element for bga housings and method for producing the same 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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