Pulsed plasma (dc/rf) deposition of high quality c films for patterning

Abstract

Embodiments of the present disclosure relate to methods for depositing an amorphous carbon layer onto a substrate, including over previously formed layers on the substrate, using a plasma-enhanced chemical vapor deposition (PECVD) process, in particular, the methods described herein utilize a combination of RF AC power and pulsed DC power to create a plasma which deposits an amorphous carbon layerwith a high ratio of sp3 (diamond-like) carbon to sp2 (graphite-like) carbon. The methods also provide for lower processing pressures, lower processing temperatures, and higher processing powers, each of which, alone or in combination, may further increase the relative fraction of sp3 carbon in the deposited amorphous carbon layer. As a result of the higher sp3 carbon fraction, the methods described herein provide amorphous carbon layers having improved density, rigidity, etch selectivity, and film stress as compared to amorphous carbon layers deposited by conventional methods.

Description

Background technique [0001] field [0002] Embodiments of the present disclosure relate to methods for depositing an amorphous carbon layer on a substrate using a plasma enhanced chemical vapor deposition (PECVD) process, including depositing over a previously formed layer on the substrate. [0003] Description of related fields [0004] Carbon hardmasks formed from amorphous carbon are used as etch masks in semiconductor device fabrication to form high aspect ratio openings (eg, aspect ratios of 2:1 or greater) in the surface of a substrate or in a surface layer of its material. Typically, the processing issues associated with forming high aspect ratio openings, including clogging, hole shape distortion, pattern distortion, top critical dimension blow up, line bowing, and profile warping, are undesirable for conventionally deposited carbon dies. result of the material properties. For example, carbon hard mold materials are known to have either or both lower material densit...

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Problems solved by technology

Furthermore, as the critical dimension (CD) shrinks and the size of the high aspect ratio openings increases, the thickness of the conventionally deposited carbon dies used to form the high aspect ratio openings also increases.

Unfortunately, a hardmask with lower transparency due to one or both of low optical K and increased thickness can cause misalignment in subsequent photolithographic processes

Additionally, processes with low etch selectivity between the die material and the underlying substrate material often rely on relatively thick dies, which increases processing time and cost

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