Pressure sensor chip, pressure sensor, and manufacturing method thereof

A method of manufacturing a pressure sensor chip, the method comprising:

• joining a first layer to a base, the first layer including a first cavity patterned therein;
• joining a second layer to a surface of the first layer opposite to the base;
• joining a third layer to a surface of the second layer opposite to the first layer, the third layer including a second cavity patterned therein, the third layer being joined in such a manner that a first diaphragm is formed in the second layer between the first cavity and the second cavity;
• and
• joining a fourth layer to a surface of the third layer opposite to the second layer, the fourth layer including a third cavity patterned therein, the fourth layer being joined in such a manner that:
• a first end of the third cavity is in communication with outside;
• a second end of the third cavity is in communication with the second cavity;
• and
• a second diaphragm is formed in the fourth layer between the second cavity and a space in communication with the outside.

A method of manufacturing a pressure sensor, the method comprising:

• joining a first layer to a base, the first layer including a first cavity patterned therein;
• joining a second layer to a surface of the first layer opposite to the base;
• joining a third layer to a surface of the second layer opposite to the first layer, the third layer including a second cavity patterned therein, the third layer being joined in such a manner that a first diaphragm is formed in the second layer between the first cavity and the second cavity;
• joining a fourth layer to a surface of the third layer opposite to the second layer, the fourth layer including a third cavity patterned therein, the fourth layer being joined in such a manner that the third cavity is in communication with the second cavity;
• and
• forming a covering portion so as to cover the base, the first layer, the second layer, the third layer, and the first layer, the covering portion including a fourth cavity and a fifth cavity, the covering portion being formed in such a manner that:
• the fourth cavity exposes the third cavity to outside;
• the fifth cavity exposes to outside a surface of the fourth layer opposite to the third layer;
• and
• a second diaphragm is formed in the fourth layer between the second cavity and the fifth cavity.