Structure, physical quantity sensor, inertial sensor, and method for manufacturing structure

A manufacturing method for manufacturing a structure of a quartz crystal substrate having a slit penetrating both main surfaces of the quartz crystal substrate and having one closed end in a longitudinal direction of the slit, which is a first direction along the main surfaces, the method comprising:

• a mask forming step of forming a mask on the quartz crystal substrate;
• and
• an etching step of forming the slit in the quartz crystal substrate by etching the quartz crystal substrate using the mask, wherein
• the mask having a shape covering an intersection point where a first straight line and a second straight line intersect each other is used in the etching step, in a plan view of the quartz crystal substrate, the first straight line corresponding to a first end surface being part of the closed end formed at an end portion of the slit and extending along a first crystal plane of the quartz crystal substrate, and the second straight line corresponding to a second end surface being part of the closed end formed at the end portion of the slit and extending along a second crystal plane of the quartz crystal substrate,
• the mask forming step including processing the shape of the mask based on a predicted intersection point of the first straight line and the second straight line, and
• the etching step includes forming the slit so that, as an inner wall of the slit, a first side surface and a second side surface extend along the first direction, the first end surface is continuous with the first side surface and has a different orientation from the first side surface, and the second end surface is continuous with the second side surface and has a different orientation from the second side surface.

A physical quantity sensor comprising:

• a structure of a quartz crystal substrate having a slit;
• and
• an oscillator supported by the structure,
• wherein the structure comprises:
• a base portion;
• a movable portion movable with respect to the base portion;
• a groove-shaped constricted portion coupling the base portion and the movable portion;
• and
• as an inner wall of the slit,
• a first side surface extending along a first direction which is a longitudinal direction of the slit;
• a second side surface extending along the first direction;
• a first end surface continuous with the first side surface and extending along a first crystal plane of the quartz crystal substrate;
• and
• a second end surface continuous with the second side surface and extending along a second crystal plane of the quartz crystal substrate,
• wherein in a plan view of the quartz crystal substrate, an intersection point where a first straight line corresponding to the first end surface and a second straight line corresponding to the second end surface intersect each other is located inside the quartz crystal substrate, and
• the oscillator is coupled to the base portion and the movable portion across the constricted portion.