Spacer Patterning for Mixed Critical Dimensions at Constant Pitch
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Solution Overview
Problem
Current Self-Aligned Double Patterning (SADP) techniques in microelectronics cannot produce patterns with different critical dimensions while maintaining the same pitch between patterns, leading to irregularities and restrictive spacer merging requirements.
Innovation Solution
A method involving the formation of sacrificial patterns with different critical dimensions in separate regions, followed by conformal deposition and anisotropic etching of structural layers to create spacers, allowing for the formation of patterns with varying critical dimensions while maintaining identical pitch through the use of Atomic Layer Deposition (ALD) techniques.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If SADP technique is used to form patterns, then pattern density is doubled, but all patterns have the same critical dimension which prevents formation of patterns with different critical dimensions
Solution Approach 1:
The substrate is divided into multiple regions, each with sacrificial patterns of different critical dimensions. This segmentation allows different regions to have different pattern densities and critical dimensions simultaneously, resolving the contradiction between uniformity and versatility.
Solution Approach 2:
Different regions of the substrate are assigned different local qualities - specifically, different sacrificial pattern critical dimensions tailored to the desired final pattern requirements. This enables each region to be optimized independently for its specific function while maintaining overall process integration.
2Adaptability or versatility
If sacrificial patterns with different critical dimensions are formed in different regions, then patterns with different critical dimensions can be achieved, but the pitch between patterns becomes inconsistent
Solution Approach 1:
Sacrificial patterns of different critical dimensions are formed in advance in different regions, with their positions and dimensions precisely predetermined. This preliminary action establishes the foundation for achieving both variable critical dimensions and consistent pitch in the final pattern, as the spacer deposition process inherently maintains uniform pitch based on the sacrificial pattern geometry.
3Productivity
If structural spacers are merged to achieve pattern density doubling, then SADP region is formed, but perfect control of space between mandrels is required which is restrictive
Solution Approach 1:
The spacer formation process is made self-aligning through conformal deposition on sacrificial patterns. The spacer width is automatically determined by the deposition thickness and the sacrificial pattern geometry, eliminating the need for precise manual control of spacing between mandrels. The process self-regulates to maintain consistent pitch and achieve the desired pattern density.
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
Enables the formation of patterns with precise critical dimension differences, ensuring consistent pitch between groups, improving pattern regularity and reducing the need for precise spacer control, thus addressing the limitations of existing SADP methods.
Implementation Method 1
conformally depositing a structural layer made of a material called 'spacer' on the substrate and the sacrificial patterns
Implementation Method 2
the use of Atomic Layer Deposition (ALD) techniques
Implementation Method 3
anisotropically etching the structural layer, so as to keep only its vertical parts, disposed on the flanks of the sacrificial patterns
Data Source
AI summary
A method for forming a first and a second group of patterns on a surface of a substrate, the first group of patterns being located in a first region of the surface of the substrate and the second group of patterns being located in a second region of the surface of the substrate, the method including forming a first sacrificial pattern and a second sacrificial pattern on the substrate, the first sacrificial pattern being located in the first region and having a first critical dimension, the second sacrificial pattern being located in the second region and having a second critical dimension strictly smaller than the first critical dimension; forming first spacers in the first region, on flanks of the first sacrificial pattern, and in the second region, on flanks of the second sacrificial pattern; forming a second spacer on a flank of each first spacer located in the second region.