Stress sensor for in-situ measurement of package-induced stress in semiconductor devices
A stress sensor is disclosed herein. The stress sensor includes a plurality of carbon nanotubes in a substrate, and first and second contacts electrically connectable with the plurality of carbon nanotubes. Methods of making and using the stress sensor are also disclosed.
1. A stress sensor comprising:
a die having an opening formed in a semiconductor substrate of the die said semiconductor substrate having a top surface;
a plurality of carbon nanotubes having first ends opposite second ends disposed in the opening wherein said plurality of carbon nanotubes are embedded within said semiconductor substrate wherein said plurality of carbon nanotubes are aligned in a direction parallel to said top surface of said semiconductor substrate; and
first and second contacts electrically connectable with the first and second ends of the plurality of carbon nanotubes, respectively.
2. The stress sensor of claim 1 , wherein the opening comprises a trench having a length, and wherein each of the plurality of nanotubes are aligned in a direction corresponding to the length of the trench.
3. The stress sensor of claim 2 , wherein the first and second contacts are each at respective first and second ends of the trench.
4. The stress sensor of claim 1 , wherein the carbon nanotubes are single-walled carbon nanotubes.
5. The stress sensor of claim 1 , wherein the carbon nanotubes are selected from the group consisting of metallic-type, dielectric-type and semiconductor-type carbon nanotubes.
6. The stress sensor of claim 1 , wherein the semiconductor substrate comprises a silicon substrate.
7. The stress sensor of claim 1 , wherein the first and second contacts are plated copper or plated gold.
8. The stress sensor of claim 1 , further comprising a transistor formed in the substate wherein said opening in said semiconductor substrate is formed to a depth which is similar to a depth of the transistor formed in the substrate.
9. The stress sensor of claim 1 wherein said first ends and said second ends of said plurality of carbon nanotubes are embedded within said semiconductor substrate.
10. The stress sensor of claim 1 wherein said first and said second contacts have a portion within said semiconductor substrate which electrically connects to said first and said second ends of the plurality of carbon nanotubes, respectively.