Segmented Showerhead Layout for Uniform Dry Etching
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Solution Overview
Problem
Conventional semiconductor manufacturing processes suffer from poor etch rate uniformity and polymer residue formation on wafer edges, leading to defects and reduced yield in integrated circuits.
Innovation Solution
A plasma treatment system with a specialized showerhead design and ion filter, optimized to distribute plasma uniformly across the wafer surface, reducing defects and improving critical dimension/depth uniformity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional plasma treatment is used for dry etching, then the etching process can be performed, but etch rate uniformity deteriorates and polymer residues form on wafer edges
Solution Approach 1:
The showerhead is divided into multiple zones with different hole densities. The first zone (central region) has a first hole density, the second zone (intermediate region) has a second hole density different from the first, and the third zone (peripheral region) has a third hole density. This segmentation allows different regions of the wafer to receive optimized plasma flux, improving etch rate uniformity across the wafer surface while reducing polymer residue accumulation at the edges.
Solution Approach 2:
Different zones of the showerhead are designed with locally optimized hole densities matched to the specific requirements of different wafer regions. The central zone uses one hole density pattern, while the peripheral zone uses a different pattern, allowing each region to receive plasma distribution tailored to its local etching needs, thereby achieving uniform etch rates and minimizing harmful polymer deposits.
2Manufacturing precision
If conventional showerhead design is used, then device complexity remains low, but etch rate uniformity deteriorates
Solution Approach 1:
The showerhead structure is segmented into three distinct zones with different hole density characteristics. This segmentation improves etch rate uniformity by providing localized plasma distribution optimization without requiring complex external control systems or multiple movable components, thus achieving enhanced precision with moderate structural complexity.
3Productivity
If plasma treatment is applied to improve etching, then productivity increases, but polymer residue formation worsens leading to reduced yield
Solution Approach 1:
The segmented showerhead design with three zones of varying hole densities enables optimized plasma distribution that maintains high etching efficiency across the entire wafer surface while specifically reducing polymer residue accumulation at the edges, thereby improving both productivity and wafer yield simultaneously.
Solution Approach 2:
By applying local quality optimization through zone-specific hole density patterns, the system maintains high productivity through efficient plasma utilization while reducing harmful polymer deposits in critical edge regions, thus preserving wafer yield without sacrificing etching speed.
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
Enhances etch rate uniformity and reduces defects, resulting in improved yield and reduced polymer residues, thereby increasing the acceptance rate of integrated circuits.
Implementation Method 1
A plasma is generated in a plasma generation chamber
Implementation Method 2
The plasma passes through a showerhead to bombard a wafer substrate
Data Source
AI summary
Methods and systems for dry etching are disclosed. The methods and systems use a showerhead with a perforated plate. The perforated plate includes a primary solid zone having no holes; a first annular zone comprising a first plurality of holes with a first total hole area; a secondary solid zone having no holes; a second annular zone comprising a second plurality of holes with a second total hole area; a third annular zone comprising a third plurality of holes with a third total hole area; and a fourth annular zone comprising a fourth plurality of holes with a fourth total hole area. The third total hole area is greater than the first total hole area and less than the second total hole area, and the fourth total hole area is greater than the second total hole area. Dry etched wafers using these systems have improved edge uniformity and improved yield.