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US 6,552,475 B2Granted
Surface acoustic wave device
AssigneeMurata Manufacturing Co., Ltd.
InventorsYoshitsugu Hori, Yuji Kimura, Kazunobu Shimoe, Shigeto Taga, Toshiyuki Fuyutsume
Life of this patent
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Abstract
A surface acoustic wave device includes a surface acoustic wave substrate having two IDT electrodes including wiring electrode portions made of aluminum disposed thereon. First, second and third metal films are laminated on each of the wiring electrode portions. The first metal film has superior bondability to aluminum, and the third metal film has superior bondability to bumps. In addition, the second metal film has an ability to suppress the diffusion of the metal defining the first metal film.
Claims21
A surface acoustic wave device comprising:
- a surface acoustic wave substrate;
- at least one interdigital electrode disposed on said surface acoustic wave substrate, said at least one interdigital electrode including a first comb-like electrode portion in which a plurality of electrode fingers are connected to each other at one end thereof, a second comb-like electrode portion in which a plurality of electrode fingers are connected to each other at one end thereof, and first and second wiring electrode portions which include lead electrodes which are electrically connected to the first and the second comb-like electrode portions, respectively, a plurality of bumps, and bonding pads which are connected to an external environment via the plurality of bumps, the electrode fingers of the first and the second comb-like electrode portions being interdigitated with each other, the first and the second comb-like electrode portions and the first and the second wiring electrode portions including an aluminum film;
- first, second and third metal films which are laminated on each of the first and second wiring electrode portions in the order of the first metal film, the second metal film, and the third metal film, the first metal film being more bondable to aluminum than the second metal film, the third metal film being more bondable to the plurality of bumps than the first metal film, and the second metal film having an ability to suppress the diffusion of metals defining the first metal film and the third metal film;
- and
- a reaction suppressing film which is disposed between the aluminum film and the first metal film for suppressing a reaction between the aluminum film and a laminate including the second metal film and the third metal film.
2 more elements
A surface acoustic wave device comprising:
- a surface acoustic wave substrate;
- at least two interdigital electrodes disposed on said surface acoustic wave substrate, each of said at least two interdigital electrodes including a first comb-like electrode portion in which a plurality of electrode fingers are connected to each other at one end thereof, a second comb-like electrode portion in which a plurality of electrode fingers are connected to each other at one end thereof, and first and second wiring electrode portions which include lead electrodes which are electrically connected to the first and the second comb-like electrode portions, respectively, a plurality of bumps made of Au, and bonding pads which are connected to an external environment via the plurality of bumps, the electrode fingers of the first and the second comb-like electrode portions being interdigitated with each other, the first and the second comb-like electrode portions and the first and the second wiring electrode portions being defined by an aluminum film;
- a laminate including first, second and third metal films disposed on each of the first and second wiring electrode portions, the first metal film being more bondable to aluminum than the second metal film, the third metal film being more bondable to the plurality of bumps than the first metal film, and the second metal film having an ability to suppress the diffusion of metals defining the first metal film and the third metal film;
- and
- a reaction suppressing film which is disposed between the aluminum film and the first metal film for suppressing a reaction between the aluminum film and a laminate including the second metal film and the third metal film.
2 more elements
A surface acoustic wave device comprising:
- a surface acoustic wave substrate;
- at least one interdigital electrode disposed on said surface acoustic wave substrate, said at least one interdigital electrode including a first comb-like electrode portion in which a plurality of electrode fingers are connected to each other at one end thereof, a second comb-like electrode portion in which a plurality of electrode fingers are connected to each other at one end thereof, and first and second wiring electrode portions which include lead electrodes which are electrically connected to the first and the second comb-like electrode portions, respectively, a plurality of bumps, and bonding pads which are connected to an external environment via the plurality of bumps, the electrode fingers of the first and the second comb-like electrode portions being interdigitated with each other, the first and the second comb-like electrode portions and the first and the second wiring electrode portions including an aluminum film;
- and
- first, second and third metal films which are laminated on each of the first and second wiring electrode portions in the order of the first metal film, the second metal film, and the third metal film, the first metal film being more bondable to aluminum than the second metal film, the third metal film being more bondable to the plurality of bumps than the first metal film, and the second metal film having an ability to suppress the diffusion of metals defining the first metal film and the third metal film;
- wherein
- the first metal film comprises at least one material selected from the group consisting of Ti, Cr and NiCr;
- the second metal film comprises at least one material selected from the group consisting of Pt, Pd and Ni;
- and
- the third metal film comprises at least one material selected from the group consisting of Ag and Au.
6 more elements
Dependencies are inferred from the claim text.