Inhibiting propagation of surface cracks in a MEMS device
AssigneeNXP USA, Inc.
InventorChad S. Dawson
Life of this patent
Estimating the term…
Abstract
A microelectromechanical systems (MEMS) device includes a structural layer having a top surface. The top surface includes surface regions that are generally parallel to one another but are offset relative to one another such that a stress concentration location is formed between them. Laterally propagating shallow surface cracks have a tendency to form in the structural layer, especially near the joints between the surface regions. A method entails fabricating the MEMS device and forming trenchesin the top surface of the structural layer of the MEMS device. The trenches act as a crack inhibition feature to largely prevent the formation of deep cracks in structural layer which might otherwise result in MEMS device failure.
Claims20
A microelectromechanical systems (MEMS) device comprising:
- a structural layer having a surface, said surface including a first surface region and a second surface region adjacent to said first surface region, said first surface region lying in a first plane that is offset from a second plane of said second surface region, said second plane being substantially parallel to said first plane, and said surface including a longitudinal joint between said first and second surface regions;
- and
- at least one trench formed in said surface of said structural layer extending across said longitudinal joint.
A microelectromechanical systems (MEMS) device comprising:
- a structural layer having a surface, said surface including a first surface region and a second surface region adjacent to said first surface region, said first surface region lying in a first plane that is offset from a second plane of said second surface region, said second plane being substantially parallel to said first plane;
- and
- a plurality of trenches formed in said surface of said structural layer extending across a longitudinal joint between said first and second surface regions, wherein each trench of said plurality of trenches exhibits a length and a width, said length being greater than said width, said length being oriented approximately perpendicular to said longitudinal joint, and said trenches extend into each of said first and second surface regions.
A microelectromechanical systems (MEMS) device comprising:
- a polysilicon structural layer having a surface, said surface including a first surface region and a second surface region adjacent to said first surface region, said first surface region lying in a first plane that is offset from a second plane of said second surface region, said second plane being substantially parallel to said first plane;
- and
- a plurality of trenches formed in said surface of said polysilicon structural layer across a longitudinal joint between said first and second surface regions, each of said trenches of said plurality of trenches extending into said first and second surface regions by a depth.
Dependencies are inferred from the claim text.