Abstract:
An interconnection structure and methods for making and detaching the same are presented for column and ball grid array (CGA and BGA) structures by using a transient solder paste on the electronic module side of the interconnection that includes fine metal powder additives to increase the melting point of the solder bond. The metal powder additives change the composition of the solder bond such that the transient melting solder composition does not completely melt at temperatures below +230° C. and detach from the electronic module during subsequent ref lows. A Pb—Sn eutectic with a lower melting point is used on the opposite end of the interconnection structure. In the first method a transient melting solder paste is applied to the I/O pad of an electronic module by means of a screening mask. Interconnect structures are then bonded to the I/O pad. In a second method, solder preforms in a composition of the transient melting solder paste are wetted onto electronic module I/O pads and interconnect columns or balls are then bonded. Detachment of an electronic module from a circuit card can then be performed by heating the circuit card assembly to a temperature above the eutectic solder melting point, but below the transient solder joint melting point.
Abstract:
A heated and pressed printed wiring board is made by filling via holes formed in layers of insulating film of the wiring board with an interlayer conducting material. The insulating film is stacked with conductor patterns, and each conductor pattern closes a via hole. The interlayer conducting material forms a solid conducting material in the via holes after a heating a pressing procedure. The solid conducting material includes two types of conducting materials. The first type of conducting material includes a metal, and the second type of conductive material includes an alloy formed by the metal and conductor metal of the conductor patterns. The conductor patterns are electrically connected reliably without relying on mere mechanical contact.
Abstract:
A liquid crystal device and a manufacturing method thereof are described. The device comprises a liquid crystal panel and an auxiliary panel formed with an IC circuit for supplying driving signals to the liquid crystal device. The auxiliary substrate is separately provided with the circuit and the function thereof is tested in advance of the assembling with the liquid crystal panel. By this procedure, the yield is substantially improved.
Abstract:
A compressible interposer comprising an interposer sheet having a plurality of apertures filled with a dielectric material having a substantially uniform suspension of conductive particles therein forming a plurality of conductive sites. Preferably, the number of conductive sites on the interposer are greater in number than the number of contact pads on the electronic components such that precise alignment of the interposer between the electronic components is not required. The apertures of the interposer sheet confine the conductive particles within the dielectric material such that during compression of the interposer between the electronic components, z-axis conductive pathways are formed without shorting in the x and y directions. Preferably, the interposer sheet comprises polyimide. Preferably, the dielectric material comprises polyimide-siloxane. Preferably, the conductive particles have a diameter of about 2 to about 20 &mgr;m and comprise of a material selected from the group consisting of copper, gold, silver, nickel, palladium, platinum, and alloys thereof. The particles may also be coated with an additional conductive material such as solder having a lower melting temperature. Most preferably, the conductive particles comprise solder coated copper particles. The conductive particles are present in an amount of about 30 to about 90 wt. % of the total weight of the conductive particles and the dielectric material.
Abstract:
An inventive method for electrical and thermal electronic component attachment is disclosed. The combination of transient liquid phase sintering (TLPS) and a permanent adhesive flux binder provides the advantages of both conventional soldering technology and conductive adhesives. This hybrid approach delivers electrical and thermal conduction through sintered metal joints and mechanical properties based on a tailorable polymer matrix. These transient liquid phase sintering conductive adhesives can utilize conventional dispensing, placement, and processing equipment. During the reflow process, metal powders in the composition undergo interparticle sintering as well as alloying to the contact pads. This process produces a strong mechanical, thermal, and electrical interconnect which ensures good conductivity that is also resistant to humidity and temperature cycling.
Abstract:
In an anisotropic conductive film, ultraresilient alloy particles, playing the role of conductive particles, are dispersed in a resin. With this configuration, the ACF reduces line defects to occur on a liquid crystal display panel and attributable thereto to one-tenth.
Abstract:
Substrates for printed circuit boards and the like, in the form of a substrate base layer and at least one adherent layer fixedly attached thereto. The adherent layer preferably comprises a thermoplastic material having a glass transition temperature in the range of about 180.degree. and about 245.degree. C., or a thermosetting material capable of B-stage curing. The preparation of the novel substrates and printed circuits using the substrates and conductive traces formed with electrically-conductive ink compositions is also described.
Abstract:
A method of making a planar, subsurface electronic circuit having at least one electronic circuit component assembled therewith is disclosed. First, three dimensional, essentially square channels interspersed with lands are formed within a dielectric material on a substrate. The channels are then filled in one pass with a curable polymeric material containing a conductive metal filler so that the upper surfaces of the circuit trace formed by this conductive material are at essentially the same level as the upper surface of the lands. Circuit components are place to engage the conductive material. The curable material is then cured after placing the electronic component(s).
Abstract:
A conductive adhesive (120) for electrically and mechanically bonding circuit terminals (105) includes a polymer (121) having a predetermined curing temperature range, a first conductive particulate material (125) suspendable in the polymer (121) for providing substantially uniform conductivity throughout the conductive adhesive (120), and a second conductive particulate material (130) suspendable in the polymer (121) for metallurgically bonding together particles of the first particulate material (125). The first conductive particulate material (125) provides substantially uniform conductivity throughout the conductive adhesive (120) and includes metallic particles having a melting point above the curing temperature of the polymer. The second conductive particulate material (130) welds together particles of the first particulate material (125) and includes metallic particles having a melting point within the curing temperature range of the polymer (121).
Abstract:
Electrically conductive adhesive compositions and methods for the preparation and use thereof, in which a solder powder, a chemically protected cross-linking agent with fluxing properties and a reactive monomer or polymer are the principal components. Depending upon the intended end use, the compositions comprise three or more of the following: a relatively high melting metal powder; solder powder; the active cross-linking agent which also serves as a fluxing agent; a resin; and a reactive monomer or polymer. The compositions are useful as improved conductive adhesives, such as for attaching electrical components to electrical circuits: the compositions comprising metal powder are ideally suited for creating the conductive paths on printed circuits. The compositions for forming conductive paths may first be applied to a substrate in the desired pattern of an electrical circuit, and then heated to cure it. During heating, the action of the cross-linking agent and optional reactive monomer or polymer within the mixture fluxes the metals, enabling sintering to occur between the metal powder and the solder powder.