Freescale Semiconductor,inc.

Cindy K Goldberg

Robert E Jones

Stanley Michael Filipiak

Terry Grant Sparks

Yeong-Jyh Tom Lii

Kathleen C Yu

John C Flake

Kirk J Strozewski

Yuri Solomentsev

Brad Smith

Bradley P Smith

To improve the mechanical strength of a wafer comprising a low-k dielectric layer, the low-k dielectric layer is formed so as to have certain regions of low dielectric constant and the remainder having a higher mechanical strength. The higher-strength regions may have a relatively-higher value of dielectric constant. Selective ultraviolet curing of a dielectric material can be performed so as to expel a porogen from the region(s) desired to have low dielectric constant. A photomask, hardmask, or opaque resist, patterned so as to define the region(s) to have lower dielectric constant, is used to shield the remainder of the dielectric material from the ultraviolet radiation. Alternatively, a layer of dielectric material can be blanket cured to lower its dielectric constant, then non-critical regions thereof can be selectively over-cured whereby to produce regions of increased mechanical strength.

Semiconductor wafer with low-K dielectric layer and process for fabrication thereof

Dummy features () are formed within an interlevel dielectric layer (). Passivation layers (and) are formed by electroless deposition to protect the underlying conductive regions (and) from being penetrated from the air gaps (). In addition, the passivation layers (and) overhang the underlying conductive regions (and), thereby defining dummy features (and) adjacent the conductive regions (and). The passivation layers (and) can be formed without additional patterning steps and help minimize misaligned vias from puncturing air gaps.

Method for forming a passivation layer for air gap formation

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Grenoble, France

Cindy K Goldberg