Sensor package with cavity created using sacrificial material
An integrated circuit package includes a semiconductor die having a first surface and a second surface. The first surface is attached to a top surface of a die attach pad, and the second surface has a sensing area thereon. A mold compound covers or encapsulates at least a portion of the die attach pad and the semiconductor die. A channel is formed in a top portion of the mold compound. The channel extends from a first side of the mold compound to a second side of the mold compound. A cavity is formed between the channel and the sensing area so that the sensing area is exposed to the environment.
1 . An integrated circuit package, comprising:
a die attach pad (DAP) having a top surface;
a semiconductor die having a first surface and a second surface, the first surface attached to the top surface of the DAP, the second surface having a sensing area thereon;
a mold compound covering at least a portion of the DAP and the semiconductor die;
a channel formed in a top portion of the mold compound, the channel including at least two side walls extending from a first side of the mold compound to a second side of the mold compound, the first side and the second side along a periphery of the package, the at least two side walls exposed to an environment exterior to the integrated circuit package; and
a cavity formed between the channel and the sensing area so that the sensing area is exposed to the environment.
2 . The integrated circuit package of claim 1 , wherein the cavity is formed within the mold compound.
3 . The integrated circuit package of claim 1 , wherein the cavity is formed by dissolving a sacrificial material after the channel has been created by sawing the mold compound.
4 . The integrated circuit package of claim 3 , wherein a size of the cavity is determined by a method used to apply the sacrificial material.
5 . The integrated circuit package of claim 1 , further comprising:
one or more bond pads on the second surface of the semiconductor die; and
the one or more bond pads each electrically coupled to a lead segment by a bonding wire.
6 . The integrated circuit package of claim 1 , wherein the sensing area is a gas sensor.
7 . The integrated circuit package of claim 1 , wherein the sensing area is a humidity sensor.
8 . The integrated circuit package of claim 1 , wherein the channel has a first depth in the top portion of the mold compound, and wherein the cavity has a second depth between the channel and the sensing area.
9 . A sensor package, comprising:
a sensor attach area on a lead frame;
a sensor device having a first surface and a second surface, the first surface attached to the sensor attach area, the second surface having a sensing area thereon;
a mold compound covering at least a portion of the lead frame and the sensor device;
a channel formed in a top portion of the mold compound, the channel including at least two side walls extending across a width of the mold compound, the at least two side walls extend between two opposite side surfaces along a periphery of the package, the at least two side walls exposed to an environment exterior to the sensor package; and
a cavity formed between the channel and the sensing area so that the sensing area is exposed to the environment.
10 . The sensor package of claim 9 , wherein the cavity is formed within the mold compound.
11 . The sensor package of claim 9 , wherein the cavity is formed by dissolving a sacrificial material after the channel has been created by sawing the mold compound.
12 . The sensor package of claim 9 , wherein an application method for the sacrificial material determines a size of the cavity.
13 . The sensor package of claim 9 , further comprising:
one or more bond pads on the second surface of the sensor device; and
the one or more bond pads each electrically coupled to a lead segment by a bonding wire.
14 . The sensor package of claim 9 , wherein the sensing area is a gas sensor.
15 . The sensor package of claim 9 , wherein the sensing area is a humidity sensor.
16 . The sensor package of claim 9 , wherein the channel has a different cross-sectional shape than that of the cavity.
17 . An integrated circuit (IC) package, comprising:
a semiconductor die including a sensor attached to a die attach pad (DAP) and electrically connected to a lead of the IC package;
a mold compound covering at least a portion of the DAP, the lead, and the semiconductor die;
a first cavity extending from a plane along a top surface of the mold compound, the first cavity extending between a plane along a first side surface of the mold compound and a plane along a second side surface of the mold compound, the first side surface and the second side surface along a periphery of the package, the first cavity exposed to an exterior environment of the IC package; and
a second cavity between the first cavity and the semiconductor die, the second cavity exposed to the environment.
18 . The sensor package of claim 17 , wherein the semiconductor die is electrically connected to the lead via a bonding wire.
19 . The sensor package of claim 17 , wherein the first cavity has a cross-sectional shape different than that of the second cavity.
20 . The sensor package of claim 17 , wherein the sensor is one of a gas sensor and a humidity sensor.