Semiconductor device, layout design method thereof, and layout design device using the same

1. A semiconductor device having a multilayer structure, each layer comprising:

a dummy pattern for ensuring a flatness thereof;

a pad area in which a bonding pad is formed;

an input-output circuit area in which an input-output circuit is formed, the input-output circuit area being adjacent to the pad area in plan view; and

a dummy pattern confined area for forbidding an arrangement of the dummy pattern in every layer included in the semiconductor device, the dummy pattern confined area being provided between the pad area and the input-output circuit area in plan view.

2. The semiconductor device according to claim 1 , wherein:

the dummy pattern confined area is provided between the pad area and the input-output circuit area adjacent thereto, only if a distance therebetween is equal to or less than a defined value set in advance; and

the defined value is set to produce a distance which allows ensuring the flatness.

3. The semiconductor device according to claim 1 , wherein:

the dummy pattern serves as a dummy wiring;

the bonding pad and the input-output circuit constitute a circuit having a multilayer pad structure, every layer thereof, being lower than the bonding pad, including a conductor arranged on the entire surface of the pad area in plan view; and

the dummy pattern confined area is provided, in plan view, to the pad area, to the input-output circuit area, and to a power separation circuit area in which a power separation circuit for separating a power system is formed.

4. The semiconductor device according to claim 1 , wherein:

the dummy pattern serves as a dummy wiring;

the bonding pad and the input-output circuit constitute a circuit having a structure in which the bonding pad is formed only on the top layer of a multilayer wiring, a wiring formed in the pad area in plan view, the wiring being included in each lower layer under the bonding pad; and

the dummy pattern confined area is provided, in plan view, to the input-output circuit area, to a power separation circuit area in which a power separation circuit for separating a power system is formed, and to an area having a predetermined width set in advance, the area being peripheral to the pad area.

5. The semiconductor device according to claim 1 , wherein:

the dummy pattern serves as a dummy activation area formed in a moiety of shallow trench isolation structure; and

the dummy pattern confined area is provided, in plan view, also to the power separation circuit area in which the power separation circuit for separating the power system is formed.

6. A method for designing a layout of a semiconductor device having a multilayer structure provided with a dummy pattern for ensuring a flatness, the method comprising:

providing a dummy pattern confined area for forbidding an arrangement of the dummy pattern to every layer in the semiconductor device, the dummy pattern confined area being provided to at least, in plan view, between a pad area and an input-output circuit area, the pad area including a bonding pad formed therein, and the input-output circuit area being adjacent to the pad area and including an input-output circuit formed therein.

7. A layout design device for designing a layout of a semiconductor device, comprising:

input means for inputting device information including placement position information of each unit constituting a semiconductor device which has a multilayer structure provided with a dummy pattern for ensuring flatness, a layout design being carried out separately for each layer constituting the semiconductor device;

search means for searching, in each layer, a presence of an area which fulfills a configuration condition of a dummy pattern confined area, the configuration condition set in advance, and the searching being based on the device information input by the input means;

confined area configuration means for setting, in each layer, the dummy pattern confined area, if an area which fulfills the configuration condition is found by the search means, the dummy pattern confined area being set in an area which corresponds to the area found; and

dummy pattern arranging means for arranging a dummy pattern in an area excluding an area in which the dummy pattern confined area is set by the confined area configuration means;

the configuration condition of the dummy pattern confined area being a condition to include, in top view, at least an area between a pad area and an input-output circuit area, the pad area including a bonding pad formed therein, and the input-output circuit area being adjacent to the pad area and including an input-output circuit formed therein.