Semiconductor device and a method of producing the same

A semiconductor device comprising:

• a semiconductor substrate including a first semiconductor layer having a first conductivity and a second semiconductor layer having a second conductivity on said first semiconductor layer, said first semiconductor layer partially having a hollow portion in a first surface opposite to said second semiconductor layer, a surface of said second semiconductor layer opposite to said first semiconductor layer having first and second areas, said first area defined by a thin portion of said semiconductor substrate provided by said hollow portion, said second area being outside said first area;
• an integrated circuit portion at said second area;
• an impurity diffusion layer with said first conductivity piercing said second semiconductor layer from said surface of said second semiconductor layer to a second surface of said first semiconductor layer contacting said second semiconductor layer, having a width with respect to said surface of said second semiconductor layer, and sectioning said second semiconductor layer into a plurality of isolated blocks on said first semiconductor layer;
• a wire on said surface of said second semiconductor layer, insulated from said second semiconductor layer except at a first end which is connected to said surface of said second semiconductor layer at said first area, said wire extending to an edge of said semiconductor substrate to have a second opposite end thereof, said wire being useable for electrochemical etching said first semiconductor layer to form said hollow portion and said thin portion, wherein said impurity diffusion layer is C-shaped and substantially surrounds said thin portion, said wire extends to the inside of said C-shaped impurity diffusion layer through an opening of said C-shaped impurity diffusion layer, and said first end is connected to said second semiconductor layer at said inside of said C-shaped impurity diffusion layer, wherein said impurity diffusion layer further extends from both ends of said C-shaped portion to a peripheral of said semiconductor substrate in parallel as first and second portions, respectively, and further extend along edges of said semiconductor substrate to have an outer C-shape around said C-shaped impurity diffusion layer, said wire extends from said first end in a space between said first and second portions, and wherein said wire does not cross said impurity diffusion layer except at an inner area of said surface of second semiconductor layer.

A semiconductor device comprising:

• a semiconductor substrate including a first semiconductor layer having a first conductivity and a second semiconductor layer having a second conductivity on said first semiconductor layer, said first semiconductor layer partially having a hollow portion in a first surface opposite to said second semiconductor layer, a surface of said second semiconductor layer opposite to said first semiconductor layer having first and second areas, said first area defined by a thin portion of said semiconductor substrate provided by said hollow portion, said second area being outside said first area;
• an integrated circuit portion at said second area;
• an impurity diffusion layer with said first conductivity piercing said second semiconductor layer from said surface of said second semiconductor layer to a second surface of said first semiconductor layer contacting said second semiconductor layer, having a width with respect to said surface of said second semiconductor layer, and sectioning said second semiconductor layer into a plurality of isolated blocks on said first semiconductor layer;
• a wire on said surface of said second semiconductor layer, insulated from said second semiconductor layer except at a first end which is connected to said surface of said second semiconductor layer at said first area, said wire extending to an edge of said semiconductor substrate to have a second opposite end thereof, said wire being useable for electrochemical etching said first semiconductor layer to form said hollow portion and said thin portion, wherein said wire does not cross said impurity diffusion layer except at said second opposite end, wherein said impurity diffusion layer is C-shaped and substantially surrounds said thin portion, said wire extends to the inside of said C-shaped impurity diffusion layer through an opening of said C-shaped impurity diffusion layer, and said first end is connected to said second semiconductor layer at said inside of said C-shaped impurity diffusion layer, and wherein said impurity diffusion layer further extends from both ends of said C-shaped portion to a peripheral of said semiconductor substrate in parallel as first and second portions, respectively, and further extend along edges of said semiconductor substrate to have an outer C-shape around said C-shape impurity diffusion layer, said wire extends from said first end in a space between said first and second portions.