Structure and method for improving high voltage breakdown reliability of a microelectronic device
A method and structure suitable for, e.g., improving high voltage breakdown reliability of a microelectronic device such as a capacitor usable for galvanic isolation of two circuits. A first dielectric layer has a first dielectric constant located over a semiconductor substrate. A metal structure located over the first dielectric layer has a side surface. A second dielectric layer having a second different dielectric constant is located adjacent the metal structure. A dielectric structure located between the side surface of the metal structure and the second dielectric layer has the first dielectric constant.
1. An electronic device, comprising:
a first dielectric layer having a first dielectric constant located over a semiconductor substrate;
a metal structure located over the first dielectric layer, the metal structure having a side surface;
a second dielectric layer having a second different dielectric constant located adjacent the metal structure; and
a dielectric structure having the first dielectric constant located between the side surface of the metal structure and the second dielectric layer.
2. The electronic device as recited in claim 1 , wherein the first dielectric layer and the dielectric structure comprise silicon nitride.
3. The electronic device as recited in claim 1 , wherein the second dielectric layer comprises silicon dioxide.
4. The electronic device as recited in claim 1 , wherein the second dielectric layer extends through an opening in the first dielectric layer to a third dielectric layer having the second dielectric constant.
5. The electronic device as recited in claim 4 , wherein the second dielectric layer extends through an opening in a fourth dielectric layer located between the first and third dielectric layers, the first, third and fourth dielectric layers having different chemical compositions.
6. The electronic device as recited in claim 1 , wherein the metal structure comprises a first capacitor plate that is coupled via the first dielectric layer to a second capacitor plate.
7. The electronic device as recited in claim 1 , wherein the first dielectric constant is greater than 6 and the second dielectric constant is less than 4.
8. The electronic device as recited in claim 1 , wherein the first dielectric layer has a first thickness where the first dielectric layer touches the metal structure and has a second smaller thickness where the first dielectric layer touches the second dielectric layer.
9. The electronic device as recited in claim 8 , wherein the first dielectric layer has a sloped portion between the first thickness and the second thickness, and the dielectric structure forms a continuous interface with the sidewall and the sloped portion.
10. A method of forming an electronic device, comprising:
forming a first dielectric layer having a first dielectric constant over a semiconductor substrate;
forming a metal structure over the first dielectric layer, the metal structure having a side surface;
forming a second dielectric layer having a second different dielectric constant adjacent the metal structure; and
forming a dielectric structure having the first dielectric constant between the side surface of the metal structure and the second dielectric layer.
11. The method as recited in claim 10 , wherein the first dielectric layer and the dielectric structure comprise silicon nitride.
12. The method as recited in claim 10 , wherein the second dielectric layer comprises silicon dioxide.
13. The method as recited in claim 10 , wherein the second dielectric layer extends through an opening in the first dielectric layer to a third dielectric layer having the second dielectric constant.
14. The method as recited in claim 13 , wherein the second dielectric layer extends through an opening in a fourth dielectric layer located between the first and third dielectric layers, the first, third and fourth dielectric layers having different chemical compositions.
15. The method as recited in claim 10 , wherein the metal structure comprises a first capacitor plate that is coupled via the first dielectric layer to a second capacitor plate.
16. The method as recited in claim 10 , wherein the first dielectric constant is about 7 and the second dielectric constant is about 4.
17. The method as recited in claim 10 , wherein the first dielectric layer has a first thickness where the first dielectric layer touches the metal structure and has a second smaller thickness where the first dielectric layer touches the second dielectric layer.
18. The method as recited in claim 17 , wherein the first dielectric layer has a sloped portion between the first thickness and the second thickness, and the dielectric structure forms a continuous interface with the sidewall and the sloped portion.