Electroplating Membrane Flow Control for Uniform Deposition
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Solution Overview
Problem
Current electroplating technologies face challenges in achieving uniform metal deposition on semiconductor substrates with small microbumping features and through silicon via (TSV) structures due to hydrodynamic issues, leading to non-uniform plating and reduced convection at the substrate surface.
Innovation Solution
The implementation of an electroplating apparatus with a cross flow manifold, an ionically resistive element, and a membrane that controls electrolyte flow, including the use of baffles and membrane cutouts to direct electrolyte flow and prevent bypassing, ensuring uniform electrolyte distribution and improved convection across the substrate.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If electrolyte flow is increased to improve convection and deposition uniformity, then plating quality improves, but electrolyte bypassing through the ionically resistive element increases, reducing flow control effectiveness
Solution Approach 1:
A membrane is introduced as an intermediary component between the electrolyte source and the ionically resistive element. This membrane selectively allows ion transport while restricting electrolyte bypassing, thereby maintaining flow control effectiveness even at higher flow rates needed for improved plating uniformity
Solution Approach 2:
The ionically resistive element utilizes porous material structure that provides controlled ionic resistance. The porous structure allows selective ion transport while creating pressure differential that prevents electrolyte bypassing, enabling both high convection for uniform plating and maintained flow control
2Ease of manufacture
If conventional electroplating is used for small microbumping features, then existing technology can be applied, but non-uniform metal deposition occurs due to hydrodynamic issues
Solution Approach 1:
The system segments the electrolyte delivery into controlled regions using the membrane and ionically resistive element structure. This segmentation creates localized flow control that addresses hydrodynamic issues in small microbumping features while maintaining overall process applicability to various substrate types
Solution Approach 2:
The invention changes the hydrodynamic parameters by introducing controlled ionic resistance and membrane-based flow restriction. These parameter changes modify the electrolyte flow characteristics to achieve uniform deposition on small features while keeping the electroplating process itself unchanged
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 solution enhances the uniformity of metal deposition, reduces within-feature non-uniformity, and improves plating quality by maintaining a high degree of cross flow within the cross flow manifold, addressing the hydrodynamic challenges and achieving more consistent plating results.
Implementation Method 1
a membrane in physical contact with the ionically resistive element, where the membrane is adapted to provide ionic transport through the membrane during electroplating
Implementation Method 2
the membrane is adapted to reduce a flow of electrolyte through the ionically resistive element during electroplating
Implementation Method 3
an ionically resistive element adapted to provide ionic transport through the ionically resistive element during electroplating
Implementation Method 4
Electrochemical deposition is now poised to fill a commercial need for sophisticated packaging and multichip interconnection technologies
Data Source
AI summary
Various embodiments described herein relate to methods and apparatus for electroplating material onto a semiconductor substrate. In some cases, one or more membrane may be provided in contact with an ionically resistive element to minimize the degree to which electrolyte passes backwards from a cross flow manifold, through the ionically resistive element, and into an ionically resistive element manifold during electroplating. The membrane may be designed to route electrolyte in a desired manner in some embodiments. In these or other cases, one or more baffles may be provided in the ionically resistive element manifold to reduce the degree to which electrolyte is able to bypass the cross flow manifold by flowing back through the ionically resistive element and across the electroplating cell within the ionically resistive element manifold. These techniques can be used to improve the uniformity of electroplating results.