| 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 cover 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 12, a crystal vibrator 5, a cover 3 and a semiconductor element 6. 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 11a containing 3 to 12 wt.% phosphorus and 5 to 20 wt.% gold is coated on a region of the metallic frame 12 to which at least the cove 3 is welded, and a 2nd nickel plating layer 11b containing 5 to 20 wt.% gold is coated on a region of the wiring layer 2 which is connected at least with an external electric circuit.
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