Microlens integration

US6953925B2 · kind B2 · utility

Assignee

• STMICROELECTRONICS, INC. · US

Inventors

• Ming Fang · Plainsboro, US
• Fuchao Wang · Plano, US
• Hai Ding · Phoenix, US

Key dates

• Filing date: Apr 28, 2003
• Grant date: Oct 11, 2005
• Expiry date: Nov 26, 2023

Classification

• Technology area (CPC H): Electricity
• CPC primary: H10F77/413

Abstract

A microlens of an inorganic material having a relatively high index of refraction is formed with a convex lower surface for refracting light from above through an underlying spacer layer to converge on a photodiode therebelow. The microlens and photodiode may be replicated in an array of such elements along with color filters and CMOS circuit elements on a semiconductor chip to provide an image sensor. The spacer layer, which has a relatively low refractive index, is subjected to a selective isotropic etch through an opening in an etch mask to define a concave surface that forms an interface with the convex lower surface of the microlens upon subsequent conformal deposition of the material of the microlens.