Method of manufacturing surface type acceleration sensor method of manufacturing
AssigneeKabushiki Kaisha Tokai Rika Denki Seisakusho
InventorsHitoshi Iwata, Makoto Murate
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Abstract
A surface type acceleration sensor includes a p-type single crystal silicon base plate, a cantilever functioning as a cantilever structure portion, and a plurality of strain gauges. The cantilever is disposed in a recess portion formed on the front face of the p-type single crystal silicon base plate so that the cantilever can be displaced in the upward and downward direction. The cantilever includes an epitaxial growth layer principally made of n-type single crystal silicon. The strain gauge is made of p-type silicon and formed on an upper face of the base end portion of the cantilever.
Claims2
A method of manufacturing a surface type acceleration sensor, said method comprising the steps of:
- forming a p-type silicon layer in a region on the front face side of the p-type single crystal silicon base plate by adding impurities;
- embedding the p-type silicon layer in an epitaxial growth layer when the epitaxial growth layer made of n-type single crystal silicon is formed on an upper face of the p-type single crystal silicon base plate;
- forming a p-type silicon layer for the formation of an opening portion on the epitaxial growth layer by adding impurities;
- forming a strain gauge made of p-type silicon on an upper face of the epitaxial growth layer;
- forming a passivation film for covering a wiring pattern after the formation of the wiring pattern connected to the strain gauge;
- changing each p-type silicon layer into a porous silicon layer when anode formation processing is conducted under the condition that an etching resist is formed on an upper face of the passivation film;
- and
- forming a cavity in a portion where the porous silicon layer is located when the porous silicon layer is removed by alkali etching.
A method of manufacturing a surface type acceleration sensor, said method comprising the steps of:
- forming a first p-type silicon layer in region on the front face side of the p-type single crystal silicon base plate by adding impurities;
- embedding the first p-type silicon layer in a first epitaxial growth layer when the first epitaxial growth layer made of n-type single crystal silicon is formed on an upper face of the p-type single crystal silicon base plate;
- forming a second p-type silicon layer in a region on the first epitaxial growth layer by adding impurities;
- embedding the second p-type silicon layer in a second epitaxial growth layer when the second epitaxial growth layer made of n-type single crystal silicon is formed on an upper face of the first epitaxial growth layer;
- forming partially a p-type silicon layer for the formation of an opening portion on an upper face of the embedded second p-type silicon layer when impurities are added;
- forming a strain gauge made of p-type silicon on an upper face of the epitaxial growth layer;
- forming a passivation film for covering a wiring pattern after the formation of the wiring pattern connected to the strain gauge;
- changing each p-type silicon layer into a porous silicon layer when anode formation processing is conducted under the condition that an etching resist is formed on an upper face of the passivation film;
- and
- forming a cavity in a portion where the porous silicon layer is located when the porous silicon layer is removed by alkali etching.
Dependencies are inferred from the claim text.