摘要:
The present invention is a method to eliminate the influence of clamp dimensional changes on the displacement measurement during the measurement of the coefficient of thermal expansion (CTE) of samples in tension. In a first embodiment clamp dimensional changes can be eliminated by making clamps from a material with near zero CTEs. In another embodiment clamp dimensional changes can be reduced by minimizing the CTE of the clamp material. Finally clamp dimensional changes are taken into account. This is achieved directly by subtracting a prerecorded baseline from the measurements; or by determining the CTE measurement for various sample lengths and obtaining the slope of a straight line through the points on a MD (measured displacement)/DT (temperature range of displacement measurement) versus sample length plot. The slope is the corrected CTE. Clamp dimensional changes can also be taken into account indirectly by obtaining a clamp displacement contribution (CDC) factor which allows to correct measured displacements to result the correct CTE.
摘要:
Polyimide is etched by contacting the polyimide with an aqueous solution of a metal hydroxide followed by contact with an acid followed by contact with an aqueous solution of a metal hydroxide. Etching of chemically cured polyimide can be enhanced by employing a presoaking in hot water. Also, partially etched chemically cured polyimide is removed with a concentrated acid solution.In preparing a metal coated polyimide structure for subsequent gold plating, two flash etching steps with the polyimide etch between are employed after developing the photoresist.
摘要:
A preassembly semiconductor device comprises substrate soldering structures extending toward chip soldering structures for forming solder connections with the chip soldering structures, i.e., the chip and the substrate are in preassembly positions relative to one another. The height of the substrate soldering structures is greater than the height of the chip soldering structures. A pre-applied underfill is contiguous with the substrate and is sufficiently thick so as to extend substantially no further than the full height of the substrate soldering structures. In another embodiment the height of the chip soldering structures is greater than the height of the substrate soldering structures and the pre-applied underfill is contiguous with the semiconductor chip and sufficiently thick so as to extend substantially no further than the full height of the chip soldering structures. A process comprises manufacturing semiconductor assemblies from these devices by soldering the semiconductor chip and the substrate to one another.
摘要:
Solder bumps of uniform height are provided on a substrate through the use of injection molded solder. Copper pillars or ball limiting metallurgy are formed over I/O pads within the channels of a patterned layer of photoresist. Solder is injected over the pillars or BLM, filling the channels. The solder, which does not contain flux, is allowed to solidify. It forms a plurality of solder structures (bumps) of equal heights. Solder injection and solidification are preferably carried out in a nitrogen environment or a forming gas environment. Molten solder can be injected in channels formed in round wafers without spillage using a carrier assembly that accommodates such wafers and a fill head.
摘要:
A process comprises forming a first electrical interconnect structure on a surface of a singulated semiconductor chip having an alignment pattern, which is scanned and stored in a scanning device prior to application of a curable underfill coating to the surface of the singulated semiconductor chip. A curable underfill coating is applied to the surface of the singulated semiconductor chip to produce a coated semiconductor chip. The scanned and stored alignment pattern is delivered to an alignment and joining device positioned adjacent to and operatively associated with a substrate having a second electrical interconnect structure alignable to make electrical contact with the first electrical interconnect structure. The coated semiconductor chip is placed in the alignment and joining device so that when the scanned and stored alignment pattern is activated the alignment and joining device positions the coated semiconductor chip so that the first electrical interconnect structure is aligned to make electrical contact with the second electrical interconnect structure. The alignment and joining device is activated to join the coated semiconductor chip to the substrate.
摘要:
A method for measuring the fracture and fatigue crack growth behavior of a material includes heating at least one sample having a first end and a second end and a pre-applied crack between the first end and the second end; heating a fixture having a lower coefficient of thermal expansion than said at least one sample; attaching the first end and the second end of the at least one sample to the fixture; cooling the at least one sample and fixture; recording the temperature at which propagation of the pre-applied crack through the width of the at least one sample occurs as the critical fracture temperature; for a plurality of samples, each sample having a different ratio of pre-applied crack length to sample width, determining the critical fracture temperature as a function of said ratio; and ranking materials by the critical fracture temperature.
摘要:
A single-mode optical waveguide with a core, surrounded by a cladding consisting of an inner soft layer and an outer harder layer is described. The outer layer has a grating structure on its inner surface, whose spatial frequency is the same as that of the guided mode. The thickness of the inner cladding is sufficient to keep the grating outside the mode field in undeformed regions of the waveguide, so that normally no out-coupling of the light results. Connections are made by crossing two such waveguides at an angle and pressing them together. This results in deformation of the two waveguides such that the gratings are brought into proximity with the cores. Light is coupled out of one waveguide and into the other in the deformed region, resulting in a self-aligning optical connection. The out-coupled light propagates normal to the waveguide axis, so errors in the crossing angle cause little change in efficiency. Because the cladding system is sufficiently resilient to recover after deformation, the connection is remakeable.
摘要:
A method of manufacturing a thermal paste, in which the method includes feeding the thermal paste into a chamber of an extruder; mixing the thermal paste at elevated temperatures; de-airing the thermal paste; and extruding the thermal paste out of the chamber through a die as a pre-form or into a cartridge, such that air channels and pseudo-grain boundaries are prevented from forming in the thermal paste.
摘要:
A semiconductor wafer and the process for aligning wafer level underfill material coated chips with a substrate via alignment marks made visible through laser dicing.
摘要:
A reversible thermal thickening grease for microelectronic packages, in which the grease contains filler particles; at least one polymer; and a binder; in which the filler particles are dispersed within the binder, in which one or more segments of the at least one polymer may be attached to the filler particles prior to dispersion in the binder, and in which the polymer collapses at temperatures below a Theta temperature and swells at temperatures above a Theta temperature. During the operation of a microelectronic package, grease pump-out and air proliferation are minimized with use of the reversible thermal thickening grease, while grease fluidity is retained under repetitive thermal stresses.