Semiconductor Metal Feature Fabrication via Sacrifice Layer
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Solution Overview
Problem
Existing methods for fabricating semiconductor integrated circuits face challenges in minimizing process-induced damage on low-k dielectric material layers, which affects IC performance and complexity during scaling down.
Innovation Solution
A method involving the formation of a patterned sacrifice layer for metal layer deposition, followed by removing the sacrifice layer to form metal features and depositing a dielectric layer between them, providing an etch-free integration scheme that reduces damage to the low-k dielectric material.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional etching methods are used to form metal interconnects, then metal features can be formed with precise profiles, but process-induced damage occurs on the low-k dielectric material layer
Solution Approach 1:
The patent extracts and removes the harmful etching process from the fabrication sequence. Instead of etching through the low-k dielectric to form metal features, the method uses a sacrifice layer that is selectively removed, allowing metal deposition without exposing the low-k dielectric to damaging etchants and plasma processes.
Solution Approach 2:
The sacrifice layer acts as an intermediary element that enables metal feature formation without direct contact between etching processes and the low-k dielectric. The sacrifice layer is temporarily introduced, patterned, and removed to facilitate metal deposition while protecting the underlying low-k dielectric material.
2Productivity
If the geometry size is scaled down to increase functional density, then production efficiency improves and costs decrease, but the complexity of IC processing and manufacturing increases
Solution Approach 1:
The patent segments the interconnect formation process into distinct stages: forming the sacrifice layer, patterning it, depositing metal, and removing the sacrifice layer. This segmentation allows each step to be optimized independently and reduces the need for complex process integration at smaller geometries.
Solution Approach 2:
The method changes the fundamental parameter of how metal features are formed - shifting from an etching-based approach to a deposition-based approach using a sacrifice layer. This parameter change simplifies the processing complexity that typically increases with scaling down to smaller technology nodes.
3Reliability
If new conductive and dielectric materials are introduced to improve interconnection performance, then IC performance improves, but process-induced damage on low-k dielectric material layer increases
Solution Approach 1:
The patent applies preliminary anti-action by introducing the sacrifice layer before metal deposition to prevent the harmful effects of etching on the low-k dielectric. This preemptive measure protects the sensitive low-k material from damage while enabling the use of advanced conductive materials for improved IC performance.
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 integration of low-k and metal interconnections, reducing process-induced damage and improving IC performance by maintaining the integrity of the low-k dielectric material.
Implementation Method 1
forming a metal layer in the openings
Implementation Method 2
forming a metal layer in the openings
Implementation Method 3
depositing a dielectric layer on sides of the metal feature
Implementation Method 4
depositing a dielectric layer on sides of the metal feature
Data Source
AI summary
A method of fabricating a semiconductor integrated circuit (IC) is disclosed. The method includes providing a substrate. A sacrifice layer (SL) is formed and patterned on the substrate. The patterned SL has a plurality of openings. The method also includes forming a metal layer in the openings and then removing the patterned SL to laterally expose at least a portion of the metal layer to form a metal feature, which has a substantial same profile as the opening. A dielectric layer is deposited on sides of the metal feature.