| 摘要 |
<p>PROBLEM TO BE SOLVED: To improve sealing reliability and obtain structure excellent in productivity, by making the surface of a trench which is adjacent to a package center, vertical to a base surface, and making the angle between the surface distant from the package center and the base surface obtuse, concerning the sectional form of a trench formed in the base. SOLUTION: A case fixing trench 8 is formed in a base 6, and the edge of the case 5 is fitted in the trench. As to the sectional form of the trench, the surface of the trench which is adjacent to a package center is vertical to the base surface, and the angle between the surface distant from the package center and the base surface is obtuse. The trench is formed in a closed loop type on the base surface. The tip of the edge of the case 5 has the same form as the case fixing trench 8. The case 5 is bonded to the base 6 by using adhesive agent 7. Thereby the internal surface of the case comes closely into contact with the vertical surface of the trench, on account of contaction of the case, and sealing reliability is improved.</p> |
