Self-Aligned Dual Damascene Process for Semiconductor Metallization
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Solution Overview
Problem
Conventional dual damascene processes face challenges in minimizing misalignment between metal lines and vias, leading to increased metal line width, reduced spacing between adjacent lines, and subsequent yield and performance issues.
Innovation Solution
A self-aligned dual damascene process where the via trench is etched only in regions common to both the metal line and via masks, using a sacrificial material layer resistant to the via etch to protect other regions and maintain consistent metal line width across regions with and without vias.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If metal lines are patterned wider near and above vias to minimize misalignment errors, then alignment precision is improved, but spacing between metal lines is reduced leading to yield and performance loss
Solution Approach 1:
The via mask is formed first before the metal line mask, establishing a reference pattern that guides subsequent metal line formation. This preliminary action ensures that vias are positioned accurately before metal lines are deposited, eliminating the need for compensatory widening of metal lines and maintaining proper spacing between adjacent lines
Solution Approach 2:
The via mask serves a dual function: it defines the via positions and simultaneously serves as a reference for positioning the metal lines. This self-service approach allows the via mask to provide alignment information for both via formation and metal line patterning, achieving precise alignment without requiring additional mask adjustments or metal line widening
2Measurement precision
If metal lines are patterned wider to compensate for misalignment, then alignment precision is improved, but spacing between adjacent metal lines is reduced
Solution Approach 1:
The via mask is formed first to establish precise via positions, creating a reference framework before metal line deposition. This preliminary patterning action ensures that subsequent metal lines can be positioned with accurate spacing relative to vias and each other, eliminating the need for widened metal lines
Solution Approach 2:
The patent replaces the mechanical approach of widening metal lines to accommodate alignment variations with a mask-based alignment system. By using the via mask as a precise positioning reference and controlling mask alignment during deposition, the process achieves accurate alignment without requiring increased metal line dimensions, thereby maintaining proper spacing
Data Source
AI summary
Structures and methods of forming metallization layers on a semiconductor component are disclosed. The method includes etching a metal line trench using a metal line mask, and etching a via trench using a via mask after etching the metal line trench. The via trench is etched only in regions common to both the metal line mask and the via mask.