Contact Hole Formation Using Sputtered Barrier Layer
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Solution Overview
Problem
The existing process for forming contact holes in semiconductor manufacturing often damages the sidewalls of the dielectric layer, leading to increased resistance and degraded performance due to the formation of CuO impurities and particles during plasma processing.
Innovation Solution
A method involving the formation of a barrier layer on the sidewalls and exposed metal surface, followed by sputtering to remove impurities and particles, which protects the dielectric layer and improves adhesion for the electrically conductive material, reducing resistance and processing steps.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If plasma processing is performed on the metal layer surface, then CuO impurities and particles are removed, but the sidewalls of the dielectric layer are damaged
Solution Approach 1:
A barrier layer is introduced as an intermediary between the metal layer and the dielectric layer sidewalls. This barrier layer protects the dielectric sidewalls from plasma damage while allowing the metal layer surface to be processed. The barrier layer is selectively removed from the metal layer surface through sputtering, enabling impurity removal without direct plasma exposure of the dielectric sidewalls.
Solution Approach 2:
The barrier layer is formed in advance before plasma processing of the metal layer. This preliminary formation of the barrier layer provides pre-protection to the dielectric sidewalls, preventing damage during subsequent plasma processing steps. The barrier layer is then selectively removed from the metal surface through sputtering to expose a clean metal surface.
2Reliability
If the barrier layer is formed on the sidewalls and metal surface, then adhesion is improved, but the barrier layer on metal surface must be removed
Solution Approach 1:
The barrier layer is formed with different functions in different locations: on the dielectric sidewalls, it provides adhesion and protection, while on the metal layer surface, it is removed through sputtering to expose a clean surface for subsequent processing. This local differentiation of the barrier layer's function resolves the contradiction between needing adhesion and needing a clean metal surface.
Solution Approach 2:
The barrier layer undergoes a parameter change through selective removal: it remains intact on the dielectric sidewalls to provide adhesion, but is removed from the metal layer surface through sputtering. This parameter change (presence/absence) in different locations resolves the contradiction between adhesion requirements and surface cleanliness requirements.
3Manufacturing precision
If sputtering is performed on the metal layer, then CuO impurities are removed and metal layer is protected, but the barrier layer on metal surface is removed
Solution Approach 1:
The barrier layer serves as a mediator that is selectively removed by sputtering from the metal layer surface. This selective removal allows the sputtering process to clean the metal surface and remove CuO impurities without requiring direct plasma exposure of the dielectric sidewalls, simplifying the overall process while maintaining high precision.
Solution Approach 2:
The chemical plasma processing method is replaced with a physical sputtering method for removing CuO impurities from the metal layer surface. This substitution allows for more precise control and selective removal of the barrier layer from the metal surface while protecting the dielectric sidewalls, improving manufacturing precision without significantly increasing process complexity.
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 effectively protects the dielectric layer, enhances adhesion, and reduces the resistance of the contact hole while using the same apparatus for sputtering and deposition, improving the overall quality and efficiency of the contact hole formation.
Implementation Method 1
removing the barrier layer on the surface of the metal layer by sputtering
Implementation Method 2
performing sputtering on the metal layer; and, filling the contact hole with an electrically conductive material
Data Source
AI summary
The invention discloses a method for forming a contact hole structure, including: providing a substrate, the substrate having a surface where a metal layer is formed; forming on the surface of the substrate a dielectric layer covering the metal layer; etching the dielectric layer to form a contact hole exposing the metal layer; forming a barrier layer on sidewalls of the contact hole and an exposed surface of the metal layer; removing the barrier layer on the surface of the metal layer by sputtering, and performing sputtering on the metal layer; and, filling the contact hole with an electrically conductive material. The invention protects the dielectric layer from being damaged and improves the quality of the formation of the contact hole, and the sputtering performed on the metal layer and the subsequent filling of the contact hole with the electrically conductive material may use the same apparatus, which reduces processing steps and improves efficiency.