Method of manufacture for semiconductor accelerometer
AssigneeNissan Motor Co., Ltd.
InventorKoichi Murakami
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Abstract
An improved method of manufacturing a semiconductor accelerometer having a cantilevered beam is shown. In the fabricating process a semiconductor substrate is divided into p-type regions and n-type regions. The substrate is immersed into an electrochemical solution with a cathode and a suitable voltage is applied. Certain portions of the substate are protected from the etching by the voltage such that the semiconductor substrate is etched to form the cantilevered beam.
Claims9
A method of manufacture for a semiconductor accelerometer with a cantilevered beam comprising:
- a step of providing an upper semiconductor layer of a first conductivity type on a semiconductor substrate of a second conductivity type opposite to the first conductivity type:
- a step of providing an electrode in ohmic contact with the upper layer;
- a step of forming a patterned region of the second conductivity type encompassing the external shape of a region to be the cantilevered beam in the upper layer;
- a step of forming a strain detecting means on the substrate;
- a step of providing a mask on the lower surface of the semiconductor substrate;
- a step of immersing the substrate with a cathode into etching solution in a condition that a voltage is applied between the electrode and the cathode to carry out an electrochemical etching such that the semiconductor substrate is etched to form the cantilevered beam.
A method for manufacturing a semiconductor accelerometer comprising the steps of:
- forming a semiconductor layer of a first conductivity type on the surface of a semiconductor substrate of a second conductivity type;
- forming in the semiconductor layer a pattern region of the second conductivity type contacting the semiconductor substrate, said pattern region being patterned so as to define the outlines of a cantilever beam composed of the semiconductor layer and a weight composed of the semiconductor substrate connected to one end of the cantilever beam;
- forming a pattern mask on the back surface of the semiconductor substrate;
- etching by an alkali etching solution the semiconductor substrate and said pattern region from the back surface of the semiconductor substrate using said pattern mask as an etching mask;
- and
- applying voltage to the semiconductor layer such that the semiconductor layer is not etched with respect to a cathode electrode immersed in the alkali etching solution during said etching, said pattern mask being patterned so as to etch said pattern region, a semiconductor substrate portion below the pattern region and a semiconductor substrate portion below the cantilever beam.
Dependencies are inferred from the claim text.