Telefonaktiebolaget Lm Ericsson (Publ)

Infineon Technologies Wireless Solutions Sweden Ab

Lars-Anders Olofsson

Bengt Ahl

Christer Olsson

Birger Karlsson

Sven-Erik Bjorksell

A method of providing thermal vias in a printed circuit board that includes one or more layers of board material is disclosed. The vias provide for conducting heat from components mounted on the board. One or more holes () are provided in a printed circuit board that may include several metal layers. A metal ball () is inserted into each hole and subjected to pressure such as to deform said ball, and tightly fixating the resultant slug against the wall () of said hole. The deformed ball or slug fixed in the hole, which may have a metallised inner surface, functions to conduct heat and/or electricity between a metallised topside () and bottom side () of the printed circuit board and also between intermediate metallised layers in the case of a multi-layer board.

Method and arrangement for providing Vias in printed circuit boards

The present invention relates to a copper ball insertion machine, for integrating metal inserts in via holes provided through a printed circuit board (PCB), comprising a motor driven X-Y table () with the PCB on top. The X-Y table () is adjustable to position a selected via hole in a predetermined location aligned with a closable outlet opening () of a movable container () for metal inserts. The container is by means of a clamping cylinder () displaceable for clamping the part of the PCB adjacent said via hole against the working surface () of said X-Y table. By means of a pivoting cylinder () the container is rotatable for feeding one metal insert through the outlet opening () into said via hole. A stamp () is drivable by a hammer cylinder () for compressing said metal insert to shape and deform it into a tight fit with the via hole.

Copper ball insertion machine

A method and apparatus for trimming a discrete surface-mounted component or a component integrated in a substrate including providing a trimmable structure mounted on the surface of a substrate for each component to be trimmed. In an exemplary embodiment, the component to be trimmed is a capacitor. In another exemplary embodiment, the trimmable structure is one electrode of a trimmable capacitor whose other electrode is integrated in the substrate, and the trimmable capacitor is connected in parallel with a surface mounted capacitor to be trimmed.

Arrangement for enabling trimming on a substrate and a method of producing a substrate that enables trimming

The present invention relates to a power transistor module for radio frequency applications, particularly for use in an amplifier stage in a radio base station or a ground transmitter for TV or radio, wherein said power transistor module comprises a support, a power transistor chip arranged thereon, outer electrical connections projecting from the module, and inner electrical connections connected between said transistor chip and said outer connections, where at least one of said outer electrical connections is comprised of a first conductor pattern arranged on a flexible foil. The invention further comprises a power amplifier comprising said power transistor module, a method for fabrication of a power amplifier, wherein said module is electrically connected to a circuit board mounted at a heat sink and is mounted at said heat sink, and finally a power amplifier manufactured according to the method.

Power transistor module, power amplifier and methods in the fabrication thereof

The present invention relates to a power transistor module for radio frequency applications, particularly for use in an amplifier stage in a radio base station or in a ground transmitter for TV or radio, wherein said power transistor module comprises a support plate, a power transistor chip arranged thereon, outer electrical connections projecting from the module for external connection and inner electrical connections connected between said transistor chip and said outer connections, at least one of said inner electrical connections comprising a first conductor pattern arranged on a flexible foil. The invention further comprises a power amplifier comprising said module, a method in the fabrication of said module, a method in the fabrication of a power amplifier, where said module is electrically connected to a circuit board mounted at a heat sink and to be mounted at said heat sink, and finally to a power amplifier manufactured according to the method.

Power transistor module, power amplifier and method in the fabrication thereof

The present invention relates to a capsule ( ) for at least one high power transistor chip ( ) for high frequencies, comprising an electrically and thermally conductive flange ( ), at least two electrically insulating substrates ( ), and at least two electrical connections ( ), and a cover member, where the high power transistor chip ( ) is arranged on the flange ( ). The high power transistor chip ( ) and the electrically insulating substrates ( ) are arranged on the flange ( ). The electrical connections ( ) are arranged on electrically insulating substrates ( ) and the electrically insulating substrates ( ) are connected to the flange ( ) and open and separate from the high power transistor chip ( ).

Capsule for at least one high power transistor chip for high frequencies

The present invention relates to a method of soldering a semiconductor chip to a substrate, such as to a capsule in an RF-power transistor, for instance. The semiconductor chip is provided with an adhesion layer consisting of a first material composition. A solderable layer consisting of a second material composition is disposed on this adhesion layer. An antioxidation layer consisting of a third material composition is disposed on said solderable layer. The antioxidation layer is coated with a layer of gold-tin solder. The chip is placed on a solderable capsule surface, via said gold-tin solder. The capsule and chip are exposed to an inert environment to which a reducing gas is delivered and the capsule and chip are subjected to a pressure substantially beneath atmospheric pressure whilst the gold-tin solder is heated to a temperature above its melting point. The gas pressure is increased whilst the gold-tin solder is molten and the temperature is lowered when a predetermined gas pressure is exceeded, so that the gold-tin solder will solidify.

Soldering of a semiconductor chip to a substrate

The present invention relates to a protective shield (1) of EMC-type, for e.g. electrical components (40) on a circuit board (30). The protective shield (1) comprises a frame (10) with associated lid (20), where said frame (10) at the end facing towards the circuit board (30) comprises a flange (12). The frame is arranged to be fastened to the circuit board (30) by means of gluing, welding or soldering. The frame (10) is intended to surround at least one component (40) so that electrical contact is formed between said circuit board (30) and said frame (10) and between said frame (10) and said lid (20).

Protective shield for electrical components

An electric protective circuit includes an electric fuse and an electric resistance loop connected in series with the fuse, the fuse and loop being mounted on a substrate. The fuse includes a solder that is connected as a resistance in a current series circuit between connection terminals and that melts at elevated temperatures caused by heating of the substrate. The solder is surrounded by a material that protects the solder against oxidation by the surrounding air and completely covers the solder, enabling the solder to contract onto the connecting terminals when it melts and break the current path. The material is temperature-stable in a solid state of normal fuse operating temperatures and includes one or a combination of waxes, resins, thermoplastics, and synthetic fluxes. The material is applied in a region or area surrounding the solder that is delimited by barrier walls that prevent the material from running away from the region. The resistance loop includes current-conducting paths that are mutually connected with bridging elements whose electrical resistance is much lower than the electrical resistance of the current-conducting paths. The resistance loop includes trimming elements for adjusting the resistance of the resistance loop.

Growing community of inventors

Järfälla, Sweden

Lars-Anders Olofsson