| 摘要 |
PROBLEM TO BE SOLVED: To overcome problems of a conventional crystal device wherein a cover cannot be strongly joined with a substrate due to the difference of a linear thermal expansion coefficient between the substrate and the cove and cracks are produced on the substrate by a thermal shock when the cover is fitted onto the substrate. SOLUTION: The crystal device 7 of this invention comprises a substrate 1 having a wiring layer 2, a metallic frame 9, a crystal vibrator 5, and a cover 3. The linear thermal expansion coefficient of the substrate 1 is selected to be 14×10<-6> to 20×10<-6> / deg.C (40 to 400 deg.C), the rigidity of the cover 3 is selected to be 50 GPa or less. A first nickel plating layer 8a containing 9 to 12 wt.% phosphorous is coated on a region of the metallic frame 9 to which at least the cover 3 is welded, and a second nickel plating layer 8b containing 5 to 40 wt.% cobalt is coated on a region of the wiring layer 2 which is connected at least with a external electric circuit.
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