Semiconductor Fin Spacing via Dummy Buffer Masks
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Solution Overview
Problem
As semiconductor devices require increasing integration density, existing manufacturing methods face challenges in precisely forming active and dummy fins with sufficient spacing to prevent etching errors and maintain reliability, particularly in achieving uniform fin shapes and reducing loading and leaning phenomena.
Innovation Solution
A method involving the formation of hard mask patterns, etch stop patterns, spacer patterns, and block mask patterns on a substrate to etch active and dummy fins with specific spacing, ensuring that dummy fins are etched without affecting active fins, and a device isolation film is deposited to prevent contact with active fin upper portions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If design rules are reduced to increase integration density, then productivity and integration density are improved, but manufacturing precision and reliability deteriorate due to difficulty in precisely forming fins with sufficient spacing
Solution Approach 1:
The patent introduces dummy fins as intermediary structures between active fins. These dummy fins act as buffer elements that prevent direct interaction between adjacent active fins during etching processes, thereby maintaining manufacturing precision while enabling reduced design rules and higher integration density.
Solution Approach 2:
The patent segments the fin structure into active fins and dummy fins with different spacing requirements. By dividing the overall fin array into functional segments (active regions and dummy regions), the design can maintain precise spacing for active fins while using tighter spacing for dummy fins, thus improving integration density without sacrificing manufacturing precision for critical structures.
2Productivity
If spacing between fins is reduced to increase integration density, then productivity is improved, but reliability worsens due to etching errors and loading/leaning phenomena
Solution Approach 1:
Dummy fins serve as intermediary buffer structures that absorb etching variability and prevent loading/leaning effects from propagating between active fins. By placing dummy fins between active fins, the design maintains reliable active fin formation even when overall spacing is reduced for higher integration density.
Solution Approach 2:
The patent employs dummy fins as pre-positioned cushioning elements that protect active fins from etching errors and mechanical stresses. These dummy structures are formed beforehand to create a protective buffer zone, preventing reliability issues before they can affect active device operation.
3Manufacturing precision
If multiple patterning processes are used to form fins with precise spacing, then manufacturing precision is improved, but device complexity and process steps increase
Solution Approach 1:
The patent merges the formation of active fins and dummy fins into a single etching process using a unified mask pattern. By combining what would traditionally require separate patterning steps into one simultaneous operation, the design achieves precise spacing for both fin types while reducing overall process complexity and the number of manufacturing 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 enhances the reliability of semiconductor devices by ensuring precise fin formation, reducing etching errors, and maintaining uniform characteristics across active fins, thereby improving integration density and product reliability.
Implementation Method 1
forming spacer patterns covering sidewalls of the etch stop patterns
Implementation Method 2
etching the substrate using the hard mask patterns and the spacer pattern as etch masks
Implementation Method 3
depositing a device isolation film on the substrate
Data Source
AI summary
A method including forming hard mask patterns on a substrate; forming etch stop patterns surrounding the hard mask patterns; forming spacer patterns covering sidewalls of the etch stop patterns; removing the etch stop patterns; etching the substrate to form active and dummy fins; forming a block mask pattern layer surrounding the active and dummy fins and forming mask etch patterns on a top surface of the block mask pattern layer; etching the block mask pattern layer to form block mask patterns surrounding the active fins; etching the dummy fins; removing the block mask patterns surrounding the active fins; and depositing a device isolation film on the substrate such that the device isolation film is not in contact with the upper portions of the active fins, wherein a spacing distance between the active fin and the dummy fin is greater than an active fin spacing distance between the active fins.