Signal processing device and image pickup apparatus using the same

A solid state image pickup apparatus comprising:

• pixels, each including a photoelectric conversion unit formed on a semiconductor substrate of a first conductivity type;
• holding capacitors for holding output signals from the pixels;
• transfer switches for transfeffing signals held in the holding capacitors to a common signal line;
• a horizontal scanning circuit for sequentially reading the output signals held in the holding capacitors to a horizontal common signal line;
• and
• a common read circuit for reading the output signals on the horizontal common signal line,
• wherein a transistor constituting the horizontal scanning circuit is disposed in a semiconductor substrate of the first conductivity type, and
• wherein the holding capacitors and the transfer switches are formed in a semiconductor layer that is disposed under the horizontal common signal line and that has a conductivity type opposite to the first conductivity type of the semiconductor substrate.

A solid state image pickup apparatus comprising:

• pixels, each including a photoelectric conversion unit formed on a semiconductor substrate of a first conductivity type;
• holding capacitors for holding output signals from the pixels;
• transfer switches for transfeffing signals held in the holding capacitors to a common signal line;
• a horizontal scanning circuit for sequentially reading the output signals held in the holding capacitors to a horizontal common signal line;
• and
• a common read circuit for reading the output signals on the horizontal common signal line,
• wherein a transistor constituting the horizontal scanning circuit is disposed in a semiconductor substrate of the first conductivity type, and
• wherein the holding capacitors and the transfer switches are formed in a semiconductor layer that is disposed under the horizontal common signal line and that has a conductivity type opposite to the first conductivity type of the semiconductor substrate.

A signal processing device comprising:

• a plurality of terminals connectable to a plurality of signal sources;
• and
• a read circuit for converting signals input from the plurality of terminals into serial signals and outputting the serial signals, the read circuit including:
• a holding capacitor connected to each of the plurality of terminals,
• a transfer switch for transfeffing a signal held in the holding capacitor to a common signal line, and
• a scanning circuit for driving the transfer switch,
• wherein a transistor constituting the scanning circuit is disposed in a semiconductor substrate of a first conductivity type, and
• wherein the holding capacitor and the transfer switch are formed in a semiconductor layer under the common signal line, in which the semiconductor layer has a conductivity type opposite to the first conductivity type of the semiconductor substrate, is connected to a ground, and shields the common signal line from a voltage change of the semiconductor substrate.