Anodic bonding method and method of producing acceleration sensor

An anodic bonding method of bonding a laminated substrate having a first planner dimension, comprising the steps of:

• preparing an anodic bonding apparatus having a first electrode and a second electrode, said first electrode having a first surface, said second electrode having a second surface facing the first surface and having a second planner dimension greater than the first planner dimension, said second electrode being formed of a material containing carbon as a main component, said first surface including a first central area;
• a first substrate placing area for placing the laminated substrate and containing the first central area;
• and a first peripheral area surrounding the first substrate placing area, said second surface including a second central area corresponding to the first central area;
• a second substrate placing area corresponding to the first substrate placing area and surrounding the second central area;
• and a second peripheral area corresponding to the first peripheral area and surrounding the second substrate placing area, said second electrode further including a curved portion curved toward the first electrode so that a distance between the first central area and the second central area becomes smaller than a distance between the first peripheral area and the second peripheral area;
• placing the laminated substrate over the first central area and the first substrate placing area of the first electrode;
• a first contact step of contacting the second central area of the second electrode with the laminated substrate to form a contact area;
• a second contact step of contacting the second substrate placing area of the second electrode with the laminated substrate to enlarge the contact area with a stress applied by a fixing member disposed in the second peripheral area so that the second electrode is pressed against the laminated substrate until the second electrode becomes substantially flat;
• and
• a bonding step of applying a voltage to the first electrode and the second electrode to bond the laminated substrate,
• wherein, in the step of placing the laminated substrate, said laminated substrate is formed of a semiconductor substrate and a glass substrate directly contacting the semiconductor substrate;
• and a plurality of protective layers is placed over the first central area and the first substrate placing area of the first electrode.

A method of producing an acceleration sensor including a laminated substrate having a first planner dimension, comprising the steps of:

• preparing an anodic bonding apparatus having a first electrode and a second electrode, said first electrode having a first surface, said second electrode having a second surface facing the first surface and having a second planner dimension greater than the first planner dimension, said second electrode being formed of a material containing carbon as a main component, said first surface including a first central area;
• a first substrate placing area for placing the laminated substrate formed of an acceleration sensor substrate with an acceleration sensor element formed thereon and a glass substrate contacting with the acceleration sensor substrate, and containing the first central area;
• and a first peripheral area surrounding the first substrate placing area, said second surface including a second central area corresponding to the first central area;
• a second substrate placing area corresponding to the first substrate placing area and surrounding the second central area;
• and a second peripheral area corresponding to the first peripheral area and surrounding the second substrate placing area, said second electrode further including a curved portion curved toward the first electrode so that a distance between the first central area and the second central area becomes smaller than a distance between the first peripheral area and the second peripheral area;
• placing the laminated substrate on the first substrate placing area of the first electrode;
• a first contact step of contacting the second central area of the second electrode with the laminated substrate to form a contact area;
• a second contact step of contacting the second substrate placing area of the second electrode with the laminated substrate to enlarge the contact area with a stress applied by a fixing member disposed in the second peripheral area so that the second electrode is pressed against the laminated substrate until the second electrode becomes substantially flat;
• and
• a bonding step of applying a voltage to the first electrode and the second electrode to bond the acceleration sensor substrate and the glass substrate,
• wherein, in the step of placing the laminated substrate, said laminated substrate is formed of a semiconductor substrate and a glass substrate directly contacting the semiconductor substrate;
• and a plurality of protective layers is placed over the first central area and the first substrate placing area of the first electrode.