Semiconductor Interconnects with Nested Sidewall Films for Contact Dimension Control
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Solution Overview
Problem
The challenge in semiconductor manufacturing is forming contact patterns with dimensions different from interconnect patterns while maintaining the fine dimensions achieved through sidewall transfer techniques, which is difficult due to the limitations of lithography resolution and the complexity of achieving varying dimensions in the manufacturing process.
Innovation Solution
The semiconductor device employs a method where interconnects are formed using a pattern of the (n+1)th sidewall film matching the nth sidewall film, allowing for a sacrificial layer to be used as a mask, enabling the formation of interconnects with dimensions smaller than lithography limits and contacts with larger dimensions, thereby simplifying the manufacturing process and improving reliability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If sidewall transfer technique is used to form fine interconnect patterns, then interconnect dimension is reduced below lithography limit, but contact pattern dimension cannot be differentiated from interconnect dimension
Solution Approach 1:
The patent applies local quality by forming a second sidewall film only in the drawing area where contacts are needed, while maintaining the first sidewall film structure in the element formation area. This allows the contact patterns to have larger dimensions than the interconnect patterns by having different sidewall film configurations in different regions of the semiconductor device.
2Ease of manufacture
If contact pattern dimension is made larger than interconnect dimension, then contact fabrication becomes easier, but manufacturing process complexity increases
Solution Approach 1:
The patent implements the nested doll principle by forming the second sidewall film on top of and surrounding the first sidewall film structure. The second sidewall film is deposited conformally over the existing first sidewall film, creating a nested configuration where the larger-dimension contact patterns are formed by adding another layer rather than creating an entirely separate structure.
3Manufacturing precision
If multiple sidewall transfer processes are repeated to reduce dimension to one fourth of lithography limit, then interconnect dimension is sufficiently reduced, but process complexity and difficulty increase
Solution Approach 1:
The patent applies segmentation by dividing the sidewall film formation into two distinct stages: a first sidewall film formation process that establishes the fine interconnect pattern dimensions, and a second sidewall film formation process that creates the larger contact pattern dimensions. This segmentation allows each process to be optimized independently, reducing the overall complexity compared to repeating the same process multiple times.
Data Source
AI summary
According to one embodiment, a semiconductor device includes interconnects extending from a element formation area to the drawing area, and connected with semiconductor elements in the element formation area and connected with contacts in the drawing area. The interconnects are formed based on a pattern of a (n+1)th second sidewall film matching a pattern of a nth (where n is an integer of 1 or more) first sidewall film on a lateral surface of a sacrificial layer. A first dimension matching an interconnect width of the interconnects and an interconnects interval in the element formation area is (k1/2n)×(λ/NA) or less when an exposure wavelength of an exposure device is λ, a numerical aperture of a lens of the exposure device is NA and a process parameter is k1. A second dimension matching an interconnect interval in the drawing area is greater than the first dimension.