Semiconductor device and semiconductor device manufacturing method with high-voltage isolation capacitor

1. A semiconductor device manufacturing method, comprising:

providing a high-voltage isolation capacitor region and a mixed-signal integrated circuit region on a substrate;

forming a bottom electrode on the high-voltage isolation capacitor region;

forming a bottom metal line on the mixed-signal integrated circuit region;

forming an inter-metal dielectric layer on the bottom electrode and the bottom metal line;

forming a top via in the inter-metal dielectric layer;

forming a low bandgap dielectric layer on the top via and the inter-metal dielectric layer;

patterning the low bandgap dielectric layer to form a patterned low bandgap dielectric layer;

depositing a thick metal film on the top via and the patterned low bandgap dielectric layer; and

patterning the thick metal film to form a top metal line on the high-voltage isolation capacitor region and form a top electrode on the mixed-signal integrated circuit region,

wherein the top metal line is connected to the top via, and wherein the patterned low bandgap dielectric layer is retained under the top electrode, and is absent under the top metal line.

2. The method of claim 1 , further comprising:

forming a hard mask layer on the thick metal film; and

patterning the hard mask layer to form a patterned hard mask layer on each of the top metal line and the top electrode.

3. The method of claim 1 , further comprising:

forming a passivation layer on, and in direct contact with, the patterned low bandgap dielectric layer, the top metal line and the top electrode.

4. The method of claim 1 , wherein the patterned low bandgap dielectric layer comprises:

a first portion overlapped with the top electrode and having a first thickness; and

a second portion outside the top electrode having a second thickness less than the first thickness.

5. The method of claim 1 ,

wherein the low bandgap dielectric layer comprises:

a first sub-low bandgap dielectric layer having a first thickness; and

a second sub-low bandgap dielectric layer having a second thickness which is greater than the first thickness.

6. The method of claim 5 , wherein the second sub-low bandgap dielectric layer comprises:

a first portion overlapped with the top electrode; and

a second portion outside the top electrode having a thickness that is less than a thickness of the first portion.

7. A semiconductor device manufacturing method, comprising:

forming a bottom electrode and a bottom metal line in a substrate;

forming an inter-metal dielectric layer on the bottom electrode and the bottom metal line;

forming an inter-metal line overlapping the bottom metal line;

forming a via connected to the inter-metal line;

depositing a low bandgap dielectric layer on the via and the inter-metal dielectric layer;

removing a portion of the low bandgap dielectric layer which overlaps the via to expose a top surface of the via, and retaining the low bandgap dielectric layer overlapped with the bottom electrode;

depositing a thick metal film on the exposed via and the low bandgap dielectric layer;

patterning the thick metal film to form a top metal line and form a top electrode,

wherein the top metal line is connected to the via, and wherein the low bandgap dielectric layer is retained under the top electrode, and is absent under the top metal line.

8. The method of claim 7 , further comprising:

forming a hard mask layer on each of the top metal line and the top electrode; and

forming a passivation layer on the hard mask layer,

wherein the passivation layer is in direct contact with the low bandgap dielectric layer, the top metal line and the top electrode.

9. The method of claim 7 , wherein the low bandgap dielectric layer comprises:

a first portion overlapped with the top electrode and having a first thickness; and

a second portion disposed outside the top electrode having a second thickness smaller than the first thickness.

10. The method of claim 7 , wherein the low bandgap dielectric layer comprises:

a first sub-low bandgap dielectric layer having a first thickness; and

a second sub-low bandgap dielectric layer having a second thickness that is greater than the first thickness.

11. The method of claim 10 , wherein the second sub-low bandgap dielectric layer comprises:

a first portion overlapped with the top electrode; and

a second portion disposed outside the top electrode having a thickness that is less than a thickness of the first portion.