Skyworks Solutions, Inc.

Silicon Laboratories Inc.

Thomas C Fowler

Dan Bernard Kasha

Russell Croman

Stefan N Mastovich

Jerome T Wenske

Ahsanul Islam

An isolation capacitor structure reduces the likelihood of breakdown in the passivation layers by physically re-shaping or dividing the top plate of the isolation capacitor into two segments. In that way, the electric field is driven down and away from the passivation surfaces. One embodiment utilizes a series capacitor formed by the top metal plate of the capacitor and an additional 'top hat' plate above the top metal plate that redirects the fields into the main isolation capacitor. Vias may be included between the top hat plate and the top metal plate. Another approach reshapes the top plate to have an integrated top hat structure and achieves similar results of directing charge down and away from the passivation layer surface breakdown paths.

Top hat structure for isolation capacitors

An integrated circuit has an isolation capacitor structure that reduces the risk of breakdown from high electric fields at the edge of the top metal plate of the capacitor. The capacitor structure includes a bottom metal plate above a substrate. A first dielectric layer of a first dielectric material is formed between the bottom metal plate and the top metal plate. The capacitor structure also includes a thin narrow ring formed of a second dielectric material located under a portion of the top metal plate. The second dielectric material has a higher dielectric constant than the first dielectric material. The thin narrow ring follows the shape of the edge of the top metal plate with a portion of the ring underneath the top metal plate and a portion outside the edge of the top metal plate to thereby be located at a place of the maximum electric field.

High dielectric constant material at locations of high fields

An integrated circuit includes a capacitor with a bottom conductive plate and a top conductive plate. A passivation layer is disposed above the top conductive plate. An intermetal dielectric layer is disposed between the bottom conductive plate and the top conductive plate and is formed of a first dielectric material. Shield layers are disposed between the top conductive plate and above the intermetal dielectric layer and extend horizontally to at least past guard rings. The shield layers include a dielectric layer formed of dielectric material having a dielectric constant greater than the material of the intermetal dielectric layer. The shield layers include horizontally offset trenches to stop horizontal flow of current in the shield layers. The offset ensures there is no vertical path from the passivation layer to lower/ground potentials through the shield layers.

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Georgetown, TX, United States of America

Thomas C Fowler