Differential pressure sensor chip, differential pressure transmitter, and method for manufacturing differential pressure sensor chip

A differential pressure sensor chip comprising:

• a first base portion including a first main surface, a second main surface opposite to the first main surface, and a first pressure introduction hole and a second pressure introduction hole that are each open on the first main surface and the second main surface;
• a semiconductor film formed on the second main surface of the first base portion;
• and
• a second base portion including a third main surface and a fourth main surface opposite to the third main surface, the third main surface being bonded to the semiconductor film,
• wherein the semiconductor film includes
• a first diaphragm configured to cover an end of the first pressure introduction hole,
• a second diaphragm configured to cover an end of the second pressure introduction hole,
• a first strain gauge provided for the first diaphragm and configured to detect a pressure of a fluid that is a measurement target, and
• a second strain gauge provided for the second diaphragm and configured to detect a pressure of the fluid that is the measurement target, and
• wherein the second base portion includes
• a first depression formed at a position on the third surface facing the first pressure introduction hole with the first diaphragm interposed therebetween and forming a first chamber together with the first diaphragm,
• a second depression formed at a position on the third surface facing the second pressure introduction hole with the second diaphragm interposed therebetween and forming a second chamber together with the second diaphragm,
• a first communication channel that makes the first chamber and the second chamber communicate to each other,
• a pressure-transmission-material introduction passage including a third depression formed on the fourth main surface and a second communication channel that makes the third depression and the first communication channel communicate to each other,
• a metal layer formed on a surface of the third depression,
• a pressure transmission material that fills the first chamber, the second chamber, the first communication channel, and the pressure-transmission-material introduction passage, and
• a sealing member that seals the third depression on the metal layer and that is formed of a metal.