ELASTIC BOUNDARY WAVE APPARATUS AND ITS MANUFACTURING METHOD

• Main Author: SHIMOE KAZUNOBU
• Format: Patent
• Language: English
• Published: 01.02.2007
• Subjects: BASIC ELECTRONIC CIRCUITRY; ELECTRICITY; IMPEDANCE NETWORKS, e.g. RESONANT CIRCUITS; RESONATORS

PROBLEM TO BE SOLVED: To provide an elastic boundary wave apparatus superior in reliability which enables the high density packaging by bonding bumps and keeps the characteristics hardly varying due to penetration of the water content, etc. SOLUTION: The elastic boundary wave apparatus 6 comprises IDTs 9 formed on a piezoelectric board 1A, an insulation film 7 laminated to cover the IDTs 9, a sound absorption film 8 laminated on the insulation film 7, and an UBM base layer 13 for forming an under-bump metal by electroplating. The UBM layer 13 extends to openings of the insulation film 7, and connected to a wiring 12 electrically connected to the IDTs 9 and to the UBM base layer 13 in the openings of the insulation film 7. The sound absorption film 8 has openings 8a formed to expose a part of the UBM base layer 13. The UBM base layer 13 is connected to a power feed line 14 at the boundary of the insulation film 7 and the sound absorption film 8, and a current is fed from the power feed line to form the UBM on the UBM base layer 13 by electroplating. COPYRIGHT: (C)2007,JPO&INPIT