Micro-electro-mechanical system package and fabrication method thereof
A micro-electro-mechanical system (MEMS) package includes a wafer with an interconnect layer disposed thereon. A first device substrate including a first MEMS device and a second device substrate including a second MEMS device are laterally spaced apart from each other and disposed on the wafer. A first and a second bond seal rings are disposed below the first and the second device substrates, respectively, and both bonded to the interconnect layer. A first handle substrate includes a first cavity having a first pressure, and is bonded to the first device substrate. A second handle substrates includes a second cavity having a second pressure different from the first pressure, and is bonded to the second device substrate. A hole is disposed in the second bond seal ring for pressure adjustment in the second cavity.
1 . A micro-electro-mechanical system (MEMS) package, comprising:
a wafer;
an interconnect layer, disposed on the wafer;
a first device substrate comprising a first MEMS device and disposed on the wafer;
a second device substrate comprising a second MEMS device, laterally spaced apart from the first device substrate and disposed on the wafer;
a first bond seal ring, disposed below the first device substrate and bonded to the interconnect layer;
a second bond seal ring, disposed below the second device substrate and bonded to the interconnect layer;
a first handle substrate, including a first cavity and bonded to the first device substrate;
a second handle substrate, including a second cavity and bonded to the second device substrate;
a hole, disposed in the second bond seal ring and vertically passing through the second bond seal ring; and
a dielectric film, disposed on the interconnect layer and adjacent to the first bond seal ring and the second bond seal ring,
wherein the first cavity has a first pressure, and the second cavity has a second pressure different from the first pressure.
2 . The MEMS package of claim 1 , wherein the hole further laterally passes through the second bond seal ring and is connected to the second cavity, and a portion of the hole is filled with the dielectric film.
3 . The MEMS package of claim 1 , wherein a height of the hole is the same as a thickness of the second bond seal ring, and a width of the hole is between 1 micrometer (μm) and 100 μm.
4 . The MEMS package of claim 1 , wherein the first MEMS device comprises a gyroscope, the second MEMS device comprises an accelerometer, and the second pressure is greater than the first pressure.
5 . The MEMS package of claim 1 , further comprising an anti-stiction coating layer conformally disposed on the second device substrate.
6 . The MEMS package of claim 1 , further comprising a first bonding layer disposed between the first device substrate and the first handle substrate, and a second bonding layer disposed between the second device substrate and the second handle substrate.
7 . The MEMS package of claim 6 , wherein the hole is extended to further vertically pass through the second device substrate.
8 . The MEMS package of claim 7 , further comprising a vent hole disposed in the second bonding layer, laterally extended between the second device substrate and the second handle substrate, and connected to the second cavity and the hole.
9 . The MEMS package of claim 8 , wherein the second device substrate and the second handle substrate construct a step structure and the vent hole is located in the step structure.
10 . The MEMS package of claim 9 , further comprising a sealing layer filled in a portion of the vent hole and on the step structure, wherein the sealing layer is in direct contact with the second device substrate.
11 . The MEMS package of claim 1 , wherein the dielectric film is in direct contact with a bottom surface of the second device substrate and a top surface of the interconnect layer.