Thin-film capacitor
AssigneeTDK Corporation
InventorsDaiki Ishii, Kazuhiro Yoshikawa, Koichi Tsunoda, Mitsuhiro Tomikawa, Junki Nakamoto, Kenichi Yoshida
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Abstract
A thin-film capacitor satisfies a relationship of CTE1>CTE2>CTE3 regarding a linear expansion coefficient CTE1 of a base, a linear expansion coefficient CTE2 of a capacitance unit, and a linear expansion coefficient CTE3 of a barrier layer. The inventors have newly found that in a case in which such a relationship is satisfied, when a temperature falls from a deposition temperature, cracking occurring in the capacitance unit of the thin-film capacitor is prevented, and cracking occurring in the barrier layer is also prevented.
Claims6
A thin-film capacitor comprising:
- a base;
- a capacitance unit provided on a main surface of the base, a plurality of electrode layers and a plurality of dielectric layers are alternately laminated in the capacitance unit in a normal direction of the main surface;
- and
- a barrier layer made of an inorganic insulating material, covering a side surface of the capacitance unit and the main surface of the base continuously, and including a first layer in direct contact with the side surface of the capacitance unit,
- wherein when a linear expansion coefficient of the base is CTE1, a linear expansion coefficient of the capacitance unit is CTE2, and a linear expansion coefficient of the first layer of the barrier layer is CTE3, a relationship of CTE1>CTE2>CTE3 is satisfied, and
- the barrier layer is constituted of a plurality of layers, in two adjacent layers of the plurality of layers constituting the barrier layer, a linear expansion coefficient of an inner layer closer to the capacitance unit is higher than a linear expansion coefficient of an outer layer further away from the capacitance unit.
A thin-film capacitor comprising:
- a base;
- a capacitance unit provided on a main surface of the base, a plurality of electrode layers and a plurality of dielectric layers are alternately laminated in the capacitance unit in a normal direction of the main surface;
- and
- a barrier layer made of an inorganic insulating material, covering a side surface of the capacitance unit and the main surface of the base continuously, and including a first layer in direct contact with the side surface of the capacitance unit,
- wherein when a linear expansion coefficient of the base is CTE1, a linear expansion coefficient of the capacitance unit is CTE2, and a linear expansion coefficient of the first layer of the barrier layer is CTE3, a relationship of CTE1>CTE2>CTE3 is satisfied, and
- when the barrier layer is constituted of a plurality of layers, in two adjacent layers of the plurality of layers constituting the barrier layer, a linear expansion coefficient of an outer layer further away from the capacitance unit is CTE3′, and a linear expansion coefficient of an inner layer closer to the capacitance unit is CTE3″, both CTE3′/CTE1 and CTE3′/CTE2 are 0.3 or smaller, a thickness of the outer layer is smaller than half a thickness of the inner layer, and CTE3′/CTE3″ is larger than 0.3.
Dependencies are inferred from the claim text.