MEMS pressure sensor built using the beol metal layers of a solid-state semiconductor process
A MEMS pressure sensor is provided having a membrane made with one of plurality of metal layers. A lid is positioned above the membrane and connected to a plurality of cavity walls at distal ends of the membrane. The lid includes an array of holes positioned on a region of the lid. A fixed metal electrode is positioned below the lid.
1 . A MEMS pressure sensor comprising:
a membrane made with one of plurality of metal layers;
a lid positioned above the membrane and connected to a plurality of cavity walls at distal ends of the membrane, wherein the lid includes an array of holes positioned on a region of the lid; and
a fixed metal electrode positioned below the lid;
wherein a set of metal layers of the plurality metal layers are configured to be a pedestal;
wherein the cavity walls are formed using at least one via structure; and
wherein the at least one via structure comprises a double ring via.
2 . The MEMS pressure sensor of claim 1 , wherein the lid is formed using a metal layer from the plurality of metal layers different from the membrane, and the membrane is formed using a first metal layer under the lid.
3 . The MEMS pressure sensor of claim 1 , wherein the membrane and the lid comprises a circular shape.
4 . The MEMS pressure sensor of claim 3 , wherein at least one of the lid and membrane comprises a diameter of about 25 μm, 50 μm, 75 μm, or 100 μm.
5 . The MEMS pressure sensor of claim 1 , wherein the metal layers are formed using the backend-of-the-line metal layers of a solid-state semiconductor process.
6 . The MEMS pressure sensor of claim 1 , wherein the array of holes protects the membrane from contaminants.
7 . The MEMS pressure sensor of claim 1 , wherein the lid comprises a second array of holes positioned on a second region on the lid different from the region defined by the array of holes.
8 . The MEMS pressure sensor of claim 7 , wherein the second region of the lid is positioned away from the membrane.
9 . The MEMS pressure sensor of claim 7 , wherein the membrane comprises a third array of holes that align with the first array of holes of the lid.
10 . The MEMS pressure sensor of claim 1 , wherein the pedestal reduces a capacitance gap at the center of the membrane.
11 . The MEMS pressure sensor of claim 10 , wherein the membrane is deflected from its central position when pressure is applied.
12 . The MEMS pressure sensor of claim 11 , wherein the membrane is connected to a lid through a via connected at a distal end of the membrane.
13 . The MEMS pressure sensor of claim 10 , wherein the membrane is integrally connected to a wing-shaped portion of one of the plurality of metal layers.
14 . The MEMS pressure sensor of claim 1 , wherein the set of metal layers are wing-shaped.
15 . A MEMS pressure sensor comprising:
a metal layer made from one of a plurality of metal layers; and
a pedestal, positioned below the metal layer, made from a set of different metal layers of the plurality of metal layers, wherein the pedestal reduces a capacitance gap at the center of the metal layer;
wherein the metal layer is deflected from its central position when pressure is applied; and
wherein the plurality of metal layers comprise of metal layers M1-M6, where the metal layer M6 is top most metal layer and the metal layer M5 is second most top metal layer, and wherein the pedestal is made with metal layers M1-M4 and a plurality of via structures V1-V3.