Granted Patent B2

US 9,766,195 · App. 13/471,609 · Granted Sep 19, 2017

Abstract

Claims (23)

1. An integrated circuit comprising:

a substrate carrying a plurality of circuit elements;

a metallization stack interconnecting the circuit elements, the metallization stack comprising a patterned upper metallization layer comprising at least one sensor electrode portion and a bond pad portion, at least the at least one sensor electrode portion of the patterned upper metallization layer being covered by a moisture barrier film; and

a passivation stack covering the metallization stack including the moisture barrier film, the passivation stack comprising a first trench exposing the at least one sensor electrode portion and a second trench exposing the bond pad portion, the first trench being filled with a sensor active material,

wherein the integrated circuit is configured as a moisture sensor and the sensor active material is a moisture-sensitive material that has a dielectric constant as a function of its moisture content, and

wherein the sensor electrode portion comprises a pair of laterally separated electrodes which form interdigitated finger electrodes.

2. The integrated circuit of claim 1 , wherein the moisture barrier film comprises a Ta 2 O 5 film.

3. The integrated circuit of claim 2 , wherein the Ta 2 O 5 film is a chemical vapor deposited film.

4. The integrated circuit of claim 1 , wherein the patterned upper metallization layer comprises aluminum.

5. The integrated circuit of claim 1 , wherein the patterned upper metallization layer is covered by the moisture barrier film apart from the bond pad portion exposed by the second trench.

6. The integrated circuit of claim 1 , wherein the pair of electrodes of the at least one sensor electrode portion is laterally separated by the sensor active material.

7. A method of manufacturing an integrated circuit having a sensor, comprising:

providing a substrate carrying a plurality of circuit elements;

forming a metallization stack over the substrate interconnecting the circuit elements, the metallization stack comprising a patterned upper metallization layer comprising at least one sensor electrode portion and a bond pad portion;

forming a moisture barrier layer covering at least the at least one sensor electrode portion of the patterned upper metallization layer;

forming a passivation stack over the metallization stack including the moisture barrier film;

patterning the passivation stack to form a first trench exposing the at least one sensor electrode portion and a second trench exposing the bond pad portion; and

filling the first trench with a sensor active material,

wherein the integrated circuit is configured as a moisture sensor and the sensor active material is a moisture-sensitive material that has a dielectric constant as a function of its moisture content, and

wherein the sensor electrode portion comprises a pair of laterally separated electrodes which form interdigitated finger electrodes.

8. The method of claim 7 , wherein the step of patterning the passivation stack to form a first trench exposing the at least one sensor electrode portion and a second trench exposing the bond pad portion comprises simultaneously forming the first trench and the second trench.

9. The method of claim 7 , wherein the step of forming the moisture barrier layer comprises depositing a Ta 2 O 5 film.

10. The method of claim 9 , wherein the step of depositing the Ta 2 O 5 film comprises depositing the film by chemical vapor deposition.

Assignments (12)