Abstract: A method of encapsulating microelectronic devices. A jet of gas is directed to an area of the device which is to remain free from encapsulating material. Polymerizable encapsulating material is then applied to the device. The material flows around the region upon which the jet impinges. The material is then cured.

Abstract: A microelectronic semiconductor element 12 is mounted on to a header 13, and integrally combined with one or more metallic sensing electrodes 20, 21 by encapsulation in a chemically and electrically inert material 19, to provide a miniature sensor assembly suitable for the detection and measurement of oxygen and other substances.Gold or gold alloy semiconductor-device bonding wires are suitable as the metallic sensing electrodes and permit low-cost, mass-production capability. The basic assembly can be engineered in various forms for different biomedical applications and is readily modified, by the addition of appropriate electro-active films to the device surface, into a sensor for a variety of chemical and biochemical substances, including enzyme substrates.

Abstract: The invention provides a chemical-responsive field-effect transducer operating in depletion-mode, or enhancement/depletion-mode, comprising: a semiconductor material having a pair of adjacent diffusion regions (1,2) of a certain doping polarity located at the surface and separated by a channel (3) of the same doping polarity, said channel being created by diffusion, ion-implantation, epitaxial growth, or creation of a surface inversion layer by controlled processing techniques or other means. The diffusion regions and channel region are supported by an insulating substrate (4) or semiconductor substrate of opposite polarity. Electrical insulator (6) and/or ion-barrier material (7) overlies the aforementioned channel region. An electroactive material (10) overlies said insulator and/or ion-barrier, such that the electroactive material will interact with substances to which it is exposed and control the charge-carrier density in the aforementioned channel.

Abstract: A selective chemosensitive microelectronic transducer is provided for the detection and measurement of chemical properties, by engineering a field-effect transistor such that source 6 and drain 7 regions are connected to bonding pads 2 and 4, and the semiconductor bulk connected to pad 1. The metal gate 8 is extended laterally to a remote area 9, and also to bonding pad 3 via a narrow metallization track 5 designed to support only a limited, predetermined electrical current in the manner of a fusible link. External electrical access to the device is achieved with wirebonding 14, and the device is selectively sealed with an inert, impervious encapsulation material 10 such that only gate area 9 remains exposed. Electroactive materials are deposited over the offset-gate area 9, or electrodeposited using connection through 8, 5 and 3. Subsequently, link 5 is open-circuited by pulsed electrical overload, creating a floating chemosensitive gate.