Semiconductor devices and methods of forming thereof

摘要

In accordance with an embodiment of the present invention, a method of forming a semiconductor device includes forming a sacrificial layer over a first surface of a workpiece having the first surface and an opposite second surface. A membrane is formed over the sacrificial layer. A through hole is etched through the workpiece from the second surface to expose a surface of the sacrificial layer. At least a portion of the sacrificial layer is removed from the second surface to form a cavity under the membrane. The cavity is aligned with the membrane.

主权项

1. A method of forming a semiconductor device, the method comprising:
forming a sacrificial layer in and over a first surface of a workpiece having the first surface and an opposite second surface by a local oxidation process, the sacrificial layer extending into the workpiece; forming a membrane over the sacrificial layer; forming a through hole through the workpiece from the second surface to expose a surface of the sacrificial layer; and removing at least a portion of the sacrificial layer from the second surface to form a cavity under the membrane, wherein the removing of at least the portion of the sacrificial layer removes all of the sacrificial layer extending into the workpiece, wherein the cavity is aligned with the membrane.