Carbon-Silicon Patterning Stack for Semiconductor Lithography
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Solution Overview
Problem
As semiconductor devices continue to shrink and pitch dimensions decrease, existing patterning methods struggle to achieve high-quality, high-density patterns with improved line width roughness (LWR) and local critical dimension uniformity (LCDU), particularly in back-end-of-the-line (BEOL) features, due to limitations in traditional optical masks and photolithography equipment.
Innovation Solution
The method involves a multi-layer patterning stack comprising a carbon-containing layer and a silicon-containing layer, deposited using techniques like CVD, ALD, or PVD, which are then patterned using lithography and etched to form masking elements that enable precise patterning of underlying layers, improving LWR and LCDU through enhanced material properties such as hardness and etch selectivity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If traditional optical masks and photolithography equipment are used, then the fabrication process is simpler and equipment cost is lower, but the pitch between elements cannot be sufficiently reduced and pattern fidelity deteriorates
Solution Approach 1:
The patterning process is divided into multiple sequential steps including depositing a carbon-containing layer, depositing a silicon-containing layer, patterning with lithography, and selective etching. This segmentation allows each step to be optimized independently, achieving sub-lithography pitch dimensions that would be impossible with a single traditional photolithography step.
Solution Approach 2:
The invention transitions from planar 2D patterning to 3D multi-layer structuring by depositing alternating carbon and silicon layers vertically stacked. This vertical dimensionality enables pitch reduction beyond the lateral resolution limits of traditional optical lithography equipment.
2Productivity
If pitch dimensions are reduced to increase device density, then more circuits can be integrated, but line width roughness increases and critical dimension uniformity deteriorates
Solution Approach 1:
The invention changes the material parameters by using carbon-containing layers with high etch selectivity relative to silicon-containing layers. This parameter change enables precise control of pattern dimensions during etching, maintaining critical dimension uniformity even at reduced pitch dimensions and increased device density.
Solution Approach 2:
The patent employs composite multi-layer structures alternating carbon-containing layers and silicon-containing layers. The carbon layers provide etch selectivity and pattern definition, while silicon layers provide structural stability. This composite approach simultaneously achieves high device density and maintains low line width roughness with uniform critical dimensions.
3Manufacturing precision
If multi-layer patterning stacks with carbon-containing layers are used, then pattern fidelity and critical dimension accuracy improve, but the number of deposition and etching steps increases
Solution Approach 1:
The carbon-containing layers serve multiple functions: they provide etch selectivity, define pattern boundaries, and act as masks for underlying layers. This self-service capability of the carbon layers reduces the need for additional dedicated mask layers, partially offsetting the increased complexity from multiple deposition and etching steps.
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
This approach allows for the creation of semiconductor devices with improved pattern fidelity and reduced line-edge roughness, enabling the production of smaller, more complex circuits with increased pattern density and critical dimension accuracy beyond the limitations of traditional lithography.
Implementation Method 1
depositing a carbon-containing layer over a target layer with a deposition process that provides for precursors delivered toward a surface and chemically modifying the precursors to obtain the carbon-containing layer on the surface
Implementation Method 2
depositing a carbon-containing layer over a target layer with a deposition process that provides for precursors delivered toward a surface and chemically modifying the precursors to obtain the carbon-containing layer on the surface
Implementation Method 3
depositing a carbon-containing layer over a target layer with a deposition process that provides for precursors delivered toward a surface and chemically modifying the precursors to obtain the carbon-containing layer on the surface
Data Source
AI summary
In one exemplary aspect, the present disclosure is directed to a method for lithography patterning. The method includes providing a substrate and forming a target layer over the substrate. A patterning layer is formed by depositing a first layer having an organic composition having a composition including at least 50 atomic percentage carbon; depositing a second layer including silicon; and depositing a photosensitive layer on the second layer. In some implementations, the first layer is deposited by ALD, CVD, or PVD processes.