Multilayer Spin-On Carbon Planarization for Uniform Semiconductor Etching
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Solution Overview
Problem
Current semiconductor manufacturing processes face challenges in achieving planarity and uniformity, particularly with the use of spin-on carbon coatings, which can lead to over-etching or under-etching issues due to topography biases in patterned features with narrow and wide gaps, resulting in defective devices.
Innovation Solution
A multilayer coating process involving two or three layers of spin-on carbon materials with crosslinking capabilities, combined with a solvent rinse operation, is applied to compensate for topography biases and achieve planarity and uniformity, using materials like 2-phenylphenol and photoacid generators to ensure even etch rates across different gap sizes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If a single layer of spin-on carbon coating is applied to patterned features, then the coating process is simple and fast, but thickness non-uniformity occurs due to topography biases in narrow and wide gap areas
Solution Approach 1:
The patent divides the coating system into multiple functional layers: a first spin-on carbon layer with crosslinking capability and a second spin-on carbon layer without crosslinking capability. This segmentation allows each layer to perform its specific function - the first layer provides structural integrity and controlled etch resistance, while the second layer fills topography variations - thereby achieving both productivity and thickness uniformity
Solution Approach 2:
The patent uses composite material structure by combining two different spin-on carbon materials with distinct properties. The first layer contains crosslinking agents that provide chemical stability and etch selectivity, while the second layer provides physical filling of gaps. This composite approach resolves the contradiction by leveraging the complementary strengths of different materials
2Device complexity
If spin-on carbon coating is used without crosslinking, then the process is simpler, but over-etching or under-etching occurs due to lack of etch rate control
Solution Approach 1:
The patent applies local quality by giving different chemical properties to different layers. The first layer contains crosslinking agents that react with etch chemicals to provide controlled etch resistance in areas requiring protection, while the second layer maintains simpler composition for areas needing different etch characteristics. This localized differentiation enables precise etch rate control without overly complicating the overall process
3Manufacturing precision
If multiple layers of spin-on carbon coating are applied, then planarity and uniformity are improved, but the process becomes more complex and time-consuming
Solution Approach 1:
The patent implements preliminary action by having the first spin-on carbon layer with crosslinking capability prepare the surface and establish a stable foundation before the second layer is applied. The crosslinking of the first layer creates a chemically stable base that prevents defects in the second layer, thereby achieving high planarity while limiting process complexity through staged preparation
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The multilayer coating process effectively compensates for thickness differences across patterned features, resulting in a uniform and planar surface, improving the reliability and productivity of semiconductor device manufacturing without incurring prohibitive costs or integration penalties.
Implementation Method 1
forming a first layer of a first planarizing material over a patterned surface of a substrate
Implementation Method 2
crosslinking a portion of the first planarizing material, forming a second layer of a second planarizing material over the first planarizing layer, crosslinking a portion of the second planarizing material
Implementation Method 3
removing a portion of the second planarizing material that is not crosslinked
Data Source
AI summary
A method of manufacturing a semiconductor device includes forming a first layer of a first planarizing material over a patterned surface of a substrate, forming a second layer of a second planarizing material over the first planarizing layer, crosslinking a portion of the first planarizing material and a portion of the second planarizing material, and removing a portion of the second planarizing material that is not crosslinked. In an embodiment, the method further includes forming a third layer of a third planarizing material over the second planarizing material after removing the portion of the second planarizing material that is not crosslinked. The third planarizing material can include a bottom anti-reflective coating or a spin-on carbon, and an acid or an acid generator. The first planarizing material can include a spin-on carbon, and an acid, a thermal acid generator or a photoacid generator.