Motohisa Nishihara

A piezoresistive integrated pressure sensor

Abstract A silicon piezoresistive integrated pressure sensor (IPS) containing sensing, temperature compensation and amplification circuits has been developed for automotive and industrial applications, etc. The chip of the IPS is bonded on a silicon support 2 mm thick, using an electrostatic bonding technique for reducing unwanted thermal stress from the support and package. Temperature invariant and laser trimmable printed thick film resistors for adjusting temperature compensation and Transfer function scaling are formed on the ceramic plate around the IPS chip, which is then mounted in a modified TO-3 package as a three terminal device. Experimental results and simulations of span temperature compensation in the sensing element bridge and the fully assembled IPS are shown here to be in good agreement. The temperature dependence of the zero and non-linearity of the IPS are also described.

Method of producing semiconductor displacement transducer

A strain gauge is formed on one main surface of a semiconductor single crystal substrate while an insulating oxide film is formed on the other main surface of the substrate. A metal junction layer including several layers inclusive of eutectic alloy layers is formed on the surface of the insulating oxide film and the thus prepared structure is mounted on a metal strain generator. By heating this assembly to temperatures approximating to the eutectic point of the eutectic alloy layer, the semiconductor substrate and the metal strain generator are joined together.

Cantilever-type displacement sensor using diffused silicon strain gauges

Abstract Two kinds of alloys have been developed as cantilever and solder materials which are suitable for semiconductors. The cantilever material is an ironnickelcobalt ternary alloy that has a high elasticity with a tensile strenght of 1GPa, and a low thermal expansion coefficient 50 × 10 −7 /K. The material for the solder is goldcoppergermanium ternary eutectic alloy that has a tensile strength of 1.1 GPa. Two strain gauges were diffused in parallel on a silicon pellet, and the pellet was bonded by the alloy solder on each surface of the cantilever, taking into account linearity and temperature effect. It was confirmed that the linearity was less than ±0.1% and a zero-point shift was under ±0.1% after 10 7 repeated stresses. The temperature effect was less than ±05% over a range of 230 – 390K using a non-linear compensation.