Removable Contact Layer for Semiconductor Interconnects
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Solution Overview
Problem
Conventional semiconductor processing techniques face challenges with poor step coverage and damage to thin seed layers during copper deposition, leading to discontinuities and non-uniformities in interconnects, especially at nanoscale features, due to issues with adhesion and contact resistance.
Innovation Solution
A method involving the selective formation of a conductive contact layer on the substrate's edge region, allowing for electrochemical processing without damaging thin seed or barrier layers, using a removable contact layer that connects to a power supply and enables uniform copper deposition.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of stationary object
If a thin seed layer (5-20 nm) is deposited to coat nanoscale features, then the feature coverage is improved, but the step coverage becomes poor and discontinuities occur
Solution Approach 1:
The patent segments the conductive layer formation into two distinct parts: a thin seed layer (5-20 nm) for coating nanoscale features and a thicker contact layer (50-200 nm) for providing robust electrical contact. This segmentation allows each layer to perform its specific function optimally without compromising the other.
Solution Approach 2:
The patent applies different thicknesses and properties of conductive material to different locations: the seed layer is kept thin (5-20 nm) where feature coverage is critical, while the contact layer is made thicker (50-200 nm) where electrical contact and current delivery are critical. This local differentiation resolves the contradiction between coverage and contact quality.
2Reliability
If electrical contacts physically touch the thin seed layer, then the electrical connection is established, but the seed layer gets damaged (smeared, scratched, lifted)
Solution Approach 1:
The patent introduces a contact layer as an intermediary between the electrical contact member and the thin seed layer. This contact layer serves as a protective mediator that receives electrical contacts without transmitting mechanical damage to the underlying seed layer, while still providing the necessary electrical connection path.
Solution Approach 2:
The contact layer is deposited beforehand to provide a robust contact surface before the thin seed layer is finalized. This preliminary action ensures that subsequent electrical contact operations will not damage the delicate seed layer structure.
3Manufacturing precision
If the seed layer thickness is reduced to 5-20 nm for nanoscale features, then the deposition precision is improved, but the adhesion and stability deteriorate
Solution Approach 1:
The patent creates a composite conductive structure consisting of a thin seed layer (5-20 nm) combined with a thicker contact layer (50-200 nm). This composite structure combines the advantages of both thin and thick layers: the thin seed layer provides precise deposition and feature coverage, while the thicker contact layer provides enhanced adhesion, stability, and electrical contact capability.
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 ensures uniform copper deposition and prevents damage to thin seed or barrier layers, improving the integrity and reliability of semiconductor interconnects by maintaining the conductive layer's integrity and reducing defects.
Implementation Method 1
The present invention provides methods of forming an electrical contact layer or a contact layer on wafers to conduct electricity to a conductive surface of a wafer to enable electrochemical processing of the wafer
Data Source
AI summary
A method is provided for manufacturing removable contact structures on the surface of a substrate to conduct electricity from a contact member to the surface during electroprocessing. The method comprises forming a conductive layer on the surface. A predetermined region of the conductive layer is selectively coated by a contact layer so that the contact member touches the contact layer as the electroprocessing is performed on the conductive layer.