Metal shield trenches and metal substrate contacts supported within the premetallization dielectric (PMD) layer of an integrated circuit using a middle end of line (MEOL) process

US10128295B2 · kind B2 · utility

Assignee

• STMicroelectronics (Crolles 2) SAS · FR

Inventors

• Sebastien Lagrasta · La Terrasse, FR
• Delia Ristoiu · Meylan, FR
• Jean-Pierre Oddou · Grenoble, FR
• Cécile Jenny · Chambéry, FR

Key dates

• Filing date: Jan 10, 2018
• Grant date: Nov 13, 2018
• Expiry date: Jan 10, 2038

Classification

• Technology area (CPC H): Electricity
• CPC primary: H10F39/813

Abstract

A semiconductor substrate includes a photodiode region, a charge storage region electrically coupled to the photodiode region and a capacitive deep trench isolation (CDTI) structure including a conductive region positioned between the photodiode region and the charge storage region. A contact etch stop layer overlies the semiconductor substrate and a premetallization dielectric layer overlies the contact etch stop layer. A first trench, filled with a metal material, extends through the premetallization dielectric layer and bottoms out at or in the contact etch stop layer. A second trench, also filled with the metal material, extends through the premetallization dielectric layer and the contact etch stop layer and bottoms out at or in the conductive region of the CDTI structure. The metal filled first trench forms an optical shield between the photodiode region and the charge storage region. The metal filled second trench forms a contact for biasing the CDTI structure.