Semiconductor device having improved RF characteristics and moisture resistance and method for manufacturing the same
A semiconductor device includes: a semiconductor substrate having a main surface; an electrode in a device region on the main surface; a metal wiring on the main surface and having a first end connected to the electrode; an electrode pad outside the device region and spaced from the metal wiring; an air gap between the main surface and an air gap forming film on the main surface, enveloping the first end of the metal wiring and the electrode, and having a first opening; a resin closing the first opening and covering a second end of the metal wiring; a liquid repellent film facing the air gap and increasing contact angle of the resin, when liquid, relative to contact angles on the semiconductor substrate and the air gap forming film; and a metal film connecting the metal wiring to the electrode pad through a second opening located in the resin.
1. A semiconductor device comprising:
a semiconductor substrate having a main surface;
an electrode in a device region of the semiconductor substrate, on the main surface of the semiconductor substrate;
a metal wiring on the main surface of the semiconductor substrate and having a first end connected to the electrode and a second end;
an electrode pad outside the device region on the main surface of the semiconductor substrate and spaced from the metal wiring;
an air gap forming film on the main surface of the semiconductor substrate;
an air gap between a part of the main surface of the semiconductor substrate and the air gap forming film, enveloping the first end of the metal wiring and the electrode, and having a first opening;
a resin closing the first opening and covering the second end of the metal wiring, without covering the electrode pad;
a liquid repellent film on an internal surface facing the air gap and increasing contact angle of the resin, when in a liquid state, relative to contact angles on the semiconductor substrate and the air gap forming film; and
a metal film connecting the metal wiring to the electrode pad through a second opening located in the resin, wherein the second end of the metal wiring does not jut out of the resin.
2. The semiconductor device according to claim 1 , wherein the metal film completely covers the area directly opposite the first opening.
3. The semiconductor device according to claim 1 , wherein the metal film is an air bridge.
4. A method for manufacturing a semiconductor device comprising:
forming an electrode in a device region on a main surface of a semiconductor substrate;
forming a metal wiring having a first end connected to the electrode on the main surface of the semiconductor substrate;
forming an electrode pad spaced from the metal wiring and outside the device region on the main surface of the semiconductor substrate;
forming an air gap forming film on the main surface of the semiconductor substrate so that an air gap enveloping the first end of the metal wiring and the electrode and having a first opening is located between a part of the main surface of the semiconductor substrate and the air gap forming film;
closing the first opening and covering a second end of the metal wiring with a resin in liquid form, and, thereafter, curing the resin;
before forming the resin, forming a liquid repellent film increasing contact angle of the resin, when in a liquid state, relative to contact angles on the semiconductor substrate and the air gap forming metal film, on an internal surface facing the air gap;
forming a second opening in the cured resin; and
forming a metal film connecting the second end of the metal wiring to the electrode pad through the second opening, wherein the second end of the metal wiring does not jut out of the resin.