Surface acoustic wave apparatus and manufacturing method therefor
AssigneeMurata Manufacturing Co., Ltd.
InventorsKenji Nishiyama, Takeshi Nakao, Michio Kadota
Life of this patent
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Abstract
In a manufacturing method for a SAW apparatus a first insulating layer is formed on the entire surface of a piezoelectric LiTaO3 substrate. By using a resist pattern used for forming an IDT electrode, the first insulating layer in which the IDT electrode is to be formed is removed. An electrode film made of a metal having a density higher than Al or an alloy primarily including such a metal is disposed in the area in which the first insulating layer is removed so as to form the IDT electrode. The resist pattern remaining on the first insulating layer is removed. A second insulating layer is formed to cover the first insulating layer and the IDT electrode.
Claims61
A surface acoustic wave apparatus comprising:
- a piezoelectric substrate including at least one of LiTaO3 and LiNbO3 and having an electromechanical coupling coefficient that is about 15% or greater;
- at least one electrode provided on the piezoelectric substrate and including at least one of a metal having a density higher than Al, an alloy including a metal having a density higher than Al, and a laminated film including a metal having a density higher than Al or an alloy including a metal having a density higher than Al;
- a first insulating layer provided on the piezoelectric substrate in an area other than an area in which said at least one electrode is provided and having a thickness which substantially equals a thickness of said at least one electrode;
- and
- a second insulating layer disposed on the piezoelectric substrate to cover said at least one electrode and said first insulating layer;
- wherein the density of said at least one electrode is about 1.5 times or greater than the density of said first insulating layer.
A surface acoustic wave apparatus comprising:
- a piezoelectric substrate;
- at least one electrode provided on the piezoelectric substrate and including one of a metal and an alloy;
- a protective metal film provided on said at least one electrode and including a metal or an alloy having higher erosion-resistant characteristics than the metal or the alloy of the at least one electrode;
- a first insulating layer provided on the piezoelectric substrate in an area other than an area in which said at least one electrode is provided and having a thickness substantially equal to a total thickness of said at least one electrode and said protective metal film;
- and
- a second insulating layer arranged to cover said protective metal film and said first insulating layer.
A manufacturing method for a surface acoustic wave apparatus, comprising the steps of:
- preparing a piezoelectric substrate;
- forming a first insulating layer on the entirety of one surface of the piezoelectric substrate;
- removing, by using a resist pattern for forming an electrode pattern including at least one electrode, at least a portion of the first insulating layer in an area in which said at least one electrode is to be formed, and;
- maintaining a laminated structure of the first insulating layer and the resist pattern in an area other than the area in which said at least one electrode is to be formed;
- forming said at least one electrode by forming an electrode film including at least one of a metal having a density higher than Al and an alloy including a metal having a density higher than Al in an area of the portion of the first insulating layer which was removed and which has a thickness substantially equal to a thickness of the first insulating layer;
- removing the resist pattern on the first insulating layer;
- and
- forming a second insulating layer to cover the first insulating layer and said at least one electrode.
A manufacturing method for a surface acoustic wave apparatus, comprising the steps of:
- preparing a piezoelectric substrate;
- forming a first insulating layer on the entirety of one surface of the piezoelectric substrate;
- removing, by using a resist pattern for forming at least one electrode, a portion of the first insulating layer in an area in which said at least one electrode is to be formed;
- maintaining a laminated structure of the first insulating layer and the resist pattern in an area other than the area in which said at least one electrode is to be formed;
- forming said at least one electrode by forming a metal or an alloy in the area of the portion of the first insulating layer which was removed;
- forming, after the formation of said at least one electrode, a protective metal film made of a metal or an alloy having higher erosion-resistant characteristics than the metal or the alloy of said at least one electrode on the entire surface of said at least one electrode such that a thickness of the protective metal film is substantially equal to a thickness of the first insulating layer;
- removing the resist pattern on the first insulating layer and the protective metal film laminated on the resist pattern;
- and
- forming a second insulating layer to cover the protective metal film formed on said at least one electrode and the first insulating layer.
A manufacturing method for a surface acoustic wave apparatus, comprising the steps of:
- preparing a piezoelectric substrate;
- forming an electrode on the piezoelectric substrate;
- forming an insulating layer to cover the electrode;
- and
- planarizing a difference of the height of the insulating layer between a portion where the electrode is present and a portion where the electrode is not present.
Dependencies are inferred from the claim text.