摘要:
A high-strength Pb-free solder alloy, based on the Sn--Ag--Zn system, is disclosed. The Pb-free solder alloy contains, in weight percent, 0.2-0.6% Zn, 1-6% Ag, one or both 0.2-0.6% In and 0.2-0.6% Bi, and the balance Sn. The addition of Zn significantly improves the mechanical strength and creep resistance of e.g., Sn--3.5% Ag eutectic solder while maintaining substantially the same level of ductility. The increase in strength is as much as 48% over that of the Sn--3.5% Ag alloy. This strengthening from the Zn additions is attributed to a uniform solidification structure and a substantial refinement of the precipitates in the alloy. Essentially all of the added Zn resides in the more corrosion-resistant, Ag-based, intermetallic precipitates, leaving the Sn-rich matrix primarily free of Zn in solid solution.
摘要:
A novel and advantageous cathode structure for a field emission display apparatus is disclosed. A given pixel comprises a multiplicity of spaced apart emitter bodies on a support. A given emitter body comprises diamond and/or rare earth boride, and has a relatively sharp geometrical feature that facilitates electron emission from the emitter body. By way of example, the emitter body comprises diamond bodies grown on a support, or it comprises a pre-existing diamond particle that was placed on the support. Such emitter bodies generally can be provided easily and at low cost, and typically have naturally occurring sharp geometrical features such as points and edges. We have also discovered that appropriately grown rare earth boride films of thickness 30 nm or less may substantially improve electron emission from emitter bodies, and some preferred embodiments of the invention comprise a cathode structure that comprises a thin layer of, e.g., LaB.sub.6 on the emitter bodies. Methods of making cathodes according to the invention are also disclosed.
摘要:
In accordance with the invention, an electronic device having one or more contact pads is placed in contact with a carrier sheet bearing an array of transferable solder particles. Heat is applied to adhere the solder to the contact pads, and solder is selectively transferred onto the contact pads. In a preferred embodiment the solder-carrying medium comprises elastomeric material and the solder particles comprise solder-coated magnetic particles. Application of a magnetic field while the elastomer is curing produces a regular array of solder coated particles. Using this method, devices having smaller than conventional contact structures can be readily interconnected.
摘要:
The present invention provides a position-sensing system which employs sensors incorporating magnetoresistive materials. The position of a magnetic information input member is determined through the resistance change of the magnetoresistive sensor in response to the magnetic field from the magnetic information input member. Exemplary magnetoresistive materials are lanthanum manganites having high magnetoresistive ratios. Two-dimensional position sensing systems for graphics tablets are also described.
摘要:
According to the present invention, an article of manufacture is provided having at least one region which includes a lead-free solder composition. The lead-free solder composition comprises an alloy of at least 50 wt. % tin and 7-30 wt. % zinc. An effective amount of silver is added to increase the ductility of the resultant alloy at least 25% over the ductility of the binary eutectic tin-zinc alloy. In a further embodiment, the present invention provides alloys useful in articles comprising lead-free solder compositions. The alloys include at least (8.0+y) wt. % zinc, 0.25 y to 0.5 y wt. % silver and at least 50 wt. % tin where y is from 0.2 to 22.
摘要:
A method for producing a circuit board having an integrated electronic component comprising providing a circuit board substrate having a first substrate surface and a second substrate surface, securing an integrated electronic component to the first substrate surface, and disposing a first dielectric layer on the first substrate surface and over the first integrated electronic component. The method additionally includes disposing a metallic layer on the first dielectric layer to produce an integrated electronic component assembly, producing in the integrated electronic component assembly at least one via having a metal lining in contact with the metallic layer, and disposing a second dielectric layer over the via and over the metallic layer. At least one metal-lined opening is formed in the second dielectric layer and in the first dielectric layer to expose at least part of the integrated electronic component, and to couple the metal lining of the opening to the first integrated electronic component to produce a circuit board having at least one integrated electronic component. A multi-layer printed circuit board having at least one prefabricated, integrated electronic component.
摘要:
Multilayer circuit lamination methods and circuit layer structures are disclosed which enable one to manufacture high-density multichip module boards and the like at lower cost, with higher yield, with higher signal densities, and with fewer processing steps.
摘要:
Structures, methods and materials for making multilayer circuit substrates are disclosed. The structures include bumped structures or microencapsulated conductive particles suitable for use in a lamination process to make a multilayer printed circuit substrate.
摘要:
Bumped semiconductor substrates and methods for forming bumped semiconductor substrates are disclosed. The bumped semiconductor substrates have a polymeric layer, which can serve as a passivation layer for chips derived from the semiconductor substrate.
摘要:
A method for deplating defective capacitors comprising forming a plurality of capacitors on a semiconductor substrate, forming a plurality of metal contacts on the plurality of capacitors, and depositing a layer of photoresist on the semiconductor substrate. The photoresist layer is patterned so that the plurality of metal contacts are exposed, which are then contacted with an electrically conductive solution. The metal contacts, which are disposed over defective capacitors, are subsequently deplated. A method for forming a multi-chip module comprising forming a thin-film polymeric interconnect structure having a pair of sides, one of which is disposed on a silicon substrate having active or passive devices and the other of which has a computer chip mounted thereon. A multi-chip module formed by the method.