Abstract: A method for the assembly of a semiconductor package that includes cleaning a surface of a chip and a surface of a heat removal device by reverse sputtering is given. The method includes sequentially coating the surface of the chip and the surface of the heat removal device with an adhesive layer, a barrier layer, and a protective layer over a target joining area. The chip and the heat removal device are placed into carrier fixtures and preheated to a target temperature. Then a metallic thermal interface material (TIM) preform is mechanically rolled onto the surface of the chip and the first and the second carrier fixtures are attached together such that the metallic TIM layer on the surface of the chip is joined to the coated surface of the heat removal device through a fluxless process. The method includes heating the joined carrier fixtures in a reflow oven.

Abstract: A method for the assembly of a semiconductor package that includes cleaning a surface of a chip and a surface of a heat removal device by reverse sputtering is given. The method includes sequentially coating the surface of the chip and the surface of the heat removal device with an adhesive layer, a barrier layer, and a protective layer over a target joining area. The chip and the heat removal device are placed into carrier fixtures and preheated to a target temperature. Then a metallic thermal interface material (TIM) preform is mechanically rolled onto the surface of the chip and the first and the second carrier fixtures are attached together such that the metallic TIM layer on the surface of the chip is joined to the coated surface of the heat removal device through a fluxless process. The method includes heating the joined carrier fixtures in a reflow oven.

Abstract: An optical membrane device and method for making such a device are described. This membrane is notable in that it comprises an optically curved surface. In some embodiments, this curved optical surface is optically concave and coated, for example, with a highly reflecting (HR) coating to create a curved mirror. In other embodiments, the optical surface is optically convex and coated with, preferably, an antireflective (AR) coating to function as a refractive or diffractive lens.

Abstract: An optical membrane device and method for making such a device are described. This membrane is notable in that it comprises an optically curved surface. In some embodiments, this curved optical surface is optically concave and coated, for example, with a highly reflecting (HR) coating to create a curved mirror. In other embodiments, the optical surface is optically convex and coated with, preferably, an antireflective (AR) coating to function as a refractive or diffractive lens.

Abstract: An optical membrane device and method for making such a device are described. This membrane is notable in that it comprises an optically curved surface. In some embodiments, this curved optical surface is optically concave and coated, for example, with a highly reflecting (HR) coating to create a curved mirror. In other embodiments, the optical surface is optically convex and coated with, preferably, an antireflective (AR) coating to function as a refractive or diffractive lens.

Abstract: A technique for creating alignment feature in mass transported substrates yields alignment features that can be located with high degrees of accuracy. Specifically, structures such as concave or convex lenses are created that yield a light pattern in transmission or reflection when the part of the substrate is imaged or a plane near the substrate is imaged. This light pattern is then used to align the substrate during subsequent lithography or packaging processes.

Abstract: An optical membrane device and method for making such a device are described. This membrane is notable in that it comprises an optically curved surface. In some embodiments, this curved optical surface is optically concave and coated, for example, with a highly reflecting (HR) coating to create a curved mirror. In other embodiments, the optical surface is optically convex and coated with, preferably, an antireflective (AR) coating to function as a refractive or diffractive lens.

Abstract: The method and apparatus of the invention create a dynamic Soret effect for propelling a target chemical constituent along a pathway. A moving temperature profile impressed upon the pathway produces consecutive alternating warmer and cooler zones along the path which transport components of a mixture down the path according to their respective diffusivities. In one embodiment, the invention provides a dynamic thermophoretic concentrator for separating a target chemical constituent from a mixture of components on the basis of diffusion coefficient by using alternate forward and backward motion of a temperature profile along the pathway, thereby accumulating an ultimate concentration of the target constituent greater than its initial concentration in the mixture.

Abstract: A technique for creating alignment feature in mass transported substrates yields alignment features that can be located with high degrees of accuracy. Specifically, structures such as concave or convex lenses are created that yield a light pattern in transmission or reflection when the part of the substrate is imaged or a plane near the substrate is imaged. This light pattern is then used to align the substrate during subsequent lithography or packaging processes.

Abstract: An apparatus and method for creating a supply of group V vapor required for various material processing applications such as crystal growth or the mass transport process, when applied to III-V materials (e.g., GaP) comprises a stable source of group V material (e.g., a GaP wafer), a process tube, and inner tube, a three-zone furnace incorporating a cold trap zone for the group III material, and a “loose” plug for the process tube. The phosphorus vapor is generated by using a source GaP wafer placed at a higher temperature than that of the main process wafer in the mass transport process. When high phosphorous vapor concentration is desired, other solid sources such as InP or red P can be used. To minimize vapor loss to the ambient, both wafers are enclosed in a quartz tube equipped with a quartz plug. However, the source wafer generates not only phosphorus but also gallium vapor. The latter interferes with mass transport and needs to be filtered out.

Abstract: A method of passively aligning optical receiving elements such as fibers to the active elements of a light generating chip includes the steps of forming two front and one side pedestal structures on the surface of a substrate body, defining a vertical sidewall of the chip to form a mating channel having an edge at a predetermined distance from the first active element, mounting the chip epi-side down on the substrate surface, and positioned the fibers in fiber-receiving channels so that a center line of each fiber is aligned to a center line of a respective active element. When mounted, the front face of the chip is abutting the contact surfaces of the two front pedestals, and the defined sidewall of the mating channel is abutting the contact surface of the side pedestal. The passive alignment procedure is also effective in aligning a single fiber to a single active element.

Abstract: A method of passively aligning optical receiving elements such as fibers to the active elements of a light generating chip includes the steps of forming two front and one side pedestal structures on the surface of a substrate body, defining a vertical sidewall of the chip to form a mating channel having an edge at a predetermined distance from the first active element, mounting the chip epi-side down on the substrate surface, and positioning the fibers in fiber-receiving channels to that a center line of each fiber is aligned to a center line of a respective active element. When mounted, the front face of the chip is abutting the contact surfaces of the two front pedestals, and the defined sidewall of the mating channel is abutting the contact surface of the side pedestal. The passive alignment procedure is also effective in aligning a single fiber to a single active element.

Abstract: Method of forming conductive members on a substrate of GaAs. Silicon is placed on the substrate surface in the desired pattern of the conductive members. The substrate is exposed to a gaseous atmosphere containing WF.sub.6. WF.sub.6 is reduced by the silicon causing tungsten to selectively deposit on the silicon but not on the exposed GaAs. The substrate is given a rapid thermal annealing treatment which causes the silicon-tungsten elements to form conductive members having a silicon rich layer at the bottom, an intermediate tungsten silicide layer, and a tungsten rich layer at the top. The conductive members form ohmic contacts with underlying heavily doped GaAs and rectifying Schottky barrier contacts with underlying lightly doped GaAs.