International Business Machines Corporation

John F Rembetski

David L Harmon

Nancy T Pascoe

Michael L Kerbaugh

Son Van Nguyen

Michael D Armacost

Steven Alfred Grundon

John Edward Cronin

Pai-Hung Pan

Paul Christian Parries

Donald M Kenney

Howard Smith Landis

Rosemary A Previti-Kelly

Suryadevara Vijayakumar Babu

Carter W Kaanta

Brian J Machesney

Joseph G Hoffarth

Allan Robert Knoll

Walter E Mlynko

Kenneth D Mack

Disclosed is a process for depositing a conformal polymer coating on selected areas of a silicon substrate. The substrate is first exposed through a mask to a gaseous plasma so as to form a film of desired pattern, the plasma comprising a compound having strong electron donating characteristics. Then, the patterned film and the remaining substrate not covered by the film are exposed to the vapor of a monomer, which condenses and polymerizes on the exposed substrate surfaces, but not on the film. The film serves to inhibit substantial deposition of the coating, so as to provide a selective deposition, where the coating is formed only on those areas of the substrate where desired.

Selective deposition process

A method for forming high aspect ratio, deep trenches in a semiconductor substrate with a composite etch mask structure including a thermally grown oxide surface layer as a plasma etch mask.

Trench mask for forming deep trenches in a semiconductor substrate, and

A semiconductor fabrication process for forming borderless contacts (130, 170, 172) using a removable mandrel (110). The process involves depositing a mandrel on an underlying barrier layer (100) designed to protect underlying structures (40) formed on a substrate (24). The mandrel is made from a material that will etch at a faster rate than the barrier layer so as to permit the formation of openings in the mandrel to be stopped on the barrier layer without penetrating such layer. After depositing a contact (130) in a first opening (120) formed in the mandrel, a second opening (140) is formed and a second contact (170) is deposited therein. Thereafter, the mandrel is removed and replaced with a layer of solid dielectric material (180).

Method of forming borderless contacts using a removable mandrel

An improved mask and method of forming a deep and width trench in a substrate and the resulting structure is disclosed. A substrate material such as silicon has deposited thereon a first layer of sacrificial material as a first component of an etch mask, the sacrificial material being a material such as polysilicon that is either etched by or absorbs the same ions which reactively ion etch the substrate. A second layer of material, which resists reactive ion etching, such as silicon dioxide, is deposited over the first layer of material as a second component of the etch mask. The silicon dioxide is patterned in the form of the trench to be formed in the substrate. The layer polysilicon material is then reactive ion etched and the reactive ion etching continued to form a trench in the silicon substrate. The polysilicon acts as a sacrificial material being etched by any ions that are reflected from the silicon dioxide or are directed at an angle such that they strike the layer of polysilicon material. Thus, only those ions which are directed essentially normal to the underlying substrate perform the trench etching. This allows the trench to have essentially straight side walls and to be of essentially uniform width.

Reactive ion etching buffer mask

An improved mask and method of forming a deep and uniform width trench in a substrate and the resulting structure is disclosed. A substrate material such as silicon has deposited thereon a first layer of sacrificial material as a first component of an etch mask, the sacrificial material being a material such as polysilicon that is either etched by or absorbs the same ions which reactively ion etch the substrate. A second layer of material, which resists reactive ion etching, such as silicon dioxide, is deposited over the first layer of material as a second component of the etch mask. The silicon dioxide is patterned in the form of the trench to be formed in the substrate. The layer polysilicon material is then reactive ion etched and the reactive ion etching continued to form a trench in the silicon substrate. The polysilicon acts as a sacrificial material being etched by any ions that are reflected from the silicon dioxide or are directed at an angle such that they strike the layer of polysilicon material. Thus, only those ions which are directed essentially normal to the underlying substrate perform the trench etching. This allows the trench to have essentially straight side walls and to be of essentially uniform width.

A plasma etching process is disclosed wherein the substrate to be etched is first exposed to an etchant gas containing a volatile organohalide. When the etch rate is stabilized, the organohalide in the etchant gas is replaced by oxygen whereby the etch rate of the substrate is immediately increased to a substantially higher value. When the above is repeatedly done a substantially higher average etch rate is obtained.

Method of plasma etching a substrate with a gaseous organohalide compound

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Burlington, VT, United States of America

John F Rembetski