Abstract:
A wiring board has a wiring circuit which is reliable and which can be easily miniaturized, and used for the production of a highly integrated, lighter, thinner, shorter, smaller and low-cost semiconductor device. This wiring board can be sealed in a plastic package. The wiring board has a metal plate and a thin-film dielectric layer formed on the surface of the metal plate. A semiconductor device is mounted on the surface of the dielectric layer or the exposed surface of the metal plate. Film wirings are formed on the dielectric layer. Each film wiring is in the form of a laminate formed by laminating, by vapor phase deposition or by plating, a an aluminum conductive layer, an adhesive layer of chromium, titanium or a laminate thereof, a diffusion barrier layer of nickel, copper or a laminate thereof, and a corrosion-preventive and wire bonding layer of gold. Such wirings may alternatively be in the form of a laminate formed by laminating an adhesive layer of chromium, aluminum, titanium or a laminate comprising at least two of such materials, a copper conductive layer, and a gold layer, or in the form of a laminate formed by laminating an aluminum conductive layer, a barrier layer of nickel, and a gold layer. Since the film wirings can be miniaturized easily, the density of the wirings can be increased. Also, since the wirings are made of aluminum or copper, they are inexpensive.
Abstract:
A method of forming a transferable pattern or image of an inorganic film by coating an embossed substrate with an inorganic layer, that may comprise one or more films, over both recessed and raised surface portions, adhesively laminating a transfer substrate to the inorganic layer coating the raised surface portions of the embossed substrate and separating the embossed substrate and the transfer substrate. The adhesive is selected such that the bond between the transfer substrate and the inorganic film on the raised surface portions is greater than the bond between the inorganic layer on the raised surface portions and the embossed substrate.The embossed substrate resulting after removal of the inorganic layer coating the raised surface portions may be modified to include additional inorganic layers over the recessed surface portions by tinning or electroplating methods such that this thickened inorganic layer may also be transferred from the embossed substrate to a transfer substrate as set forth above.
Abstract:
A flexible circuit suitable for high density applications and having a long flexural life is disclosed. A thin film metallic ground plane deposited on a dielectric substrate electrically shields the conductor traces in the flexible circuit and eliminates cross-talk between conductor traces without reducing the flexibility or the flexural life of the flexible circuit.
Abstract:
The present invention provides an improved method for manufacturing circuit boards with high power, high density interconnects. Printed circuit board technology, integrated circuit technology, and heavy-build electroless plating are combined to produce multilayer circuit boards comprised of substrates with different interconnect densities. In the higher density substrates, thick metallized layers are built-up by combining additive and subtractive techniques. These thicker foils minimize DC voltage drop so that conductors can run for longer distances. The conductors are substantially more square than their thin film equivalents, thus providing better performance for high frequency signals. Power distribution capabilities are enhanced by the present invention, so that circuit boards fully populated with dense, high-speed, high-power integrated circuits can easily be supplied with their necessary power requirements.
Abstract:
A pattern is formed on a substrate by providing on the substrate a dielectric composition; defining a pattern in said dielectric; depositing metal and then micromachining the metal to provide the desired pattern on the substrate.
Abstract:
A multi-layer ceramic substrate assembly comprising a multi-layer ceramic substrate including a via-conductor and an interconnecting line and having a surface, a first soldering pad on the surface of the substrate and electrically connected to the via-conductor, a second soldering pad on the surface of the substrate adjacent to the first soldering pad, a connecting pattern on the surface of the substrate for electrically connecting the first and second soldering pads, the connecting pattern being made of an electric conductor wettable with a solder, and a solder dam formed on the connecting pattern between the first and second soldering pads, the solder dam being made of a metal or a metal alloy or compound not wettable with a solder. The electric conductivity of the connecting pattern is carried by a metal having a good electric conductivity and the solder dam is made of a metal or a metal alloy or compound not wettable with a solder, whereby the solder dam stops a flow of a solder through the dam or under the dam. A simple and reliable process for forming such a solder dam is also provided.
Abstract:
A method of preparing a substrate such as a semiconductor chip or ceramic thin film having vias for soldering to a substrate requires that a first metal that is resistive to solder bonding be deposited on the backside of the semiconductor device. The deposited metal is removed from the surface of the semiconductor device, leaving the vias of the semiconductor device having the first metal deposited through them. This technique is useful in any requirement requiring a solder or brazing barrier. This is, a photolithographic process in conjunction with a refractory or nonsolderable metal deposit is used to achieve an alloy or solder barrier.
Abstract:
A metal film (12) for providing internal electrodes (22) is formed on a back film (11) made of a material such as polyethylene terephthalate by a thin film forming method such as vapor deposition or sputtering. A ceramic green sheet (14) is prepared. Then the metal film (12) is transferred onto the green sheet from the back film (11). In order to form the metal film (12) to be transferred into prescribed patterns, the metal film (12) may be partially removed from the back film (11) to leave only specific parts which are correlative with the prescribed patterns. Alternatively, only specific parts, which are correlative with the prescribed patterns, of the back film (11) may be pressed against the ceramic green sheet (14). A plurality of such ceramic green sheets (14), onto which the parts of the metal films (120 are transferred, have been stacked with each other.
Abstract:
The formation of metal oxide contaminants on the surfaces of thin metal films by out-diffusion primarily through the grain boundaries thereof of metal from an underlayer is inhibited by conducting heat cycling of such layered metal structures in an ambient gas mixture composed of inert gas, such as nitrogen, containing a sufficient amount of active gas, such as, hydrogen, carbon monoxide, or the like, substantially to suppress such out-diffusion.
Abstract:
A carrier (10) is vapor-vacuum deposited with a vapor-vacuum deposited first metallic layer (14) of 10-90 nm in thickness. The carrier and vapor-vacuum deposited metal layers are selected of materials which, after vapor-vacuum depositing, adhere with less than about 3 pounds per linear inch of width, e.g., aluminum and copper or copper and copper. A second metallic layer (16) is electrolytically deposited to the vapor-vacuum deposited layer to increase the thickness of the first and second metal layers, taken together, to about 1-12 microns. The carrier and first and second metal layers are bonded under heat and pressure to a dielectric substrate (18). Thereafter, the carrier is peeled away leaving the vapor-vacuum deposited and electrolytically plated layers adhered to the dielectric substrate. Although the vapor-vacuum deposited layer and the electrolytically deposited layers may both be the same metal, such as copper which is preferred for circuit boards, the vapor-vacuum deposited layer may also be a relatively inactive metal, such as aluminum, chrome, zinc, or nickel, to protect the underlying electrolytically deposited metal layer from corrosion and staining.