Fluorine-Free Copper Seed Layer for Conformal Interconnect Fill
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Solution Overview
Problem
As via and trench widths in integrated circuits decrease, the conductivity and fill ability of interconnections are affected due to non-uniform thickness of barrier and seed layers deposited by physical vapor deposition, and trace amounts of fluorine in copper seed layers can cause electromigration issues.
Innovation Solution
The use of fluorine-free organometallic precursors for atomic layer deposition (ALD) or chemical vapor deposition (CVD) to form seed layers, which reduces residue and enhances conformality, preventing overhang and improving adhesion and conductivity, along with the introduction of a copper seed layer that promotes uniform current flow during electroplating.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If physical vapor deposition (PVD) is used to deposit barrier layer or seed layer into narrow via or trench, then deposition can be achieved, but the thickness of the via or trench becomes non-uniform
Solution Approach 1:
The patent replaces physical vapor deposition (PVD) with chemical vapor deposition (CVD) or atomic layer deposition (ALD) methods to deposit barrier and seed layers. These chemical deposition methods provide conformal coating that ensures uniform thickness throughout narrow vias and trenches, eliminating the non-uniform thickness problem associated with PVD while improving fill ability.
Solution Approach 2:
The patent changes the deposition method from physical vapor deposition to chemical vapor deposition or atomic layer deposition. This parameter change in the deposition process enables conformal film formation with uniform thickness distribution in high-aspect-ratio structures, simultaneously improving both manufacturing precision and ease of operation.
2Manufacturing precision
If PVD-deposited material forms overhang at opening of via or trench, then deposition is complete, but the via or trench is pinched-off and cannot be filled with conductive material
Solution Approach 1:
The patent substitutes PVD with CVD or ALD deposition techniques that produce conformal films without overhang formation. These chemical deposition methods deposit material uniformly on all surfaces including horizontal and vertical walls, preventing pinch-off and enabling complete filling of vias and trenches with conductive material.
Solution Approach 2:
The patent changes the deposition mechanism from physical vapor deposition to chemical vapor deposition or atomic layer deposition. This fundamental parameter change results in conformal film growth that maintains uniform thickness and prevents overhang formation, thereby eliminating the pinch-off effect and improving productivity in interconnect fabrication.
3Manufacturing precision
If fluorine-containing organometallic precursors are used for copper seed layer deposition, then seed layer can be formed, but fluorine migrates and causes electromigration issues
Solution Approach 1:
The patent extracts and removes fluorine from the organometallic precursor molecules used for copper seed layer deposition. By using fluorine-free precursors, the source of fluorine contamination is eliminated, preventing fluorine migration that would otherwise cause electromigration issues and improve reliability while maintaining adhesion properties.
Solution Approach 2:
The patent changes the chemical composition parameter of the organometallic precursor by eliminating fluorine atoms from the molecular structure. This parameter change in the precursor chemistry prevents fluorine contamination in the copper seed layer, thereby resolving the electromigration reliability issue while preserving the adhesion function of the seed layer.
4Area of moving object
If via and trench widths are reduced, then device density increases, but conductivity and fill ability of interconnections deteriorate
Solution Approach 1:
The patent replaces PVD with CVD or ALD deposition methods to form barrier and seed layers in narrow vias and trenches. These chemical deposition methods provide conformal coating that maintains uniform thickness even in high-aspect-ratio structures, ensuring adequate conductivity and fill ability as device dimensions are reduced to increase density.
Solution Approach 2:
The patent changes the deposition method from physical to chemical vapor deposition, and uses fluorine-free organometallic precursors. These parameter changes enable conformal film formation with uniform thickness and eliminate fluorine contamination, thereby maintaining conductivity and fill ability as via and trench widths are reduced for higher device density.
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 improved conformality and reliability of interconnections by reducing fluorine contamination and enhancing the adhesion and conductivity of the seed layer, addressing issues of electromigration and fill ability in narrow vias and trenches.
Implementation Method 1
The use of fluorine-free organometallic precursors for atomic layer deposition (ALD) or chemical vapor deposition (CVD) to form seed layers
Implementation Method 2
The use of fluorine-free organometallic precursors for atomic layer deposition (ALD) or chemical vapor deposition (CVD) to form seed layers
Implementation Method 3
interconnection material, such as copper, is introduced by electroplating in a sufficient amount to fill the via and trench
Data Source
AI summary
A method including introducing a fluorine-free organometallic precursor in the presence of a substrate; and forming a conductive layer including a moiety of the organometallic precursor on the substrate according to an atomic layer or chemical vapor deposition process. A method including forming an opening through a dielectric layer to a contact point; introducing a fluorine-free copper film precursor and a co-reactant; and forming a copper-containing seed layer in the opening. A system including a computer including a microprocessor electrically coupled to a printed circuit board, the microprocessor including conductive interconnect structures formed from fluorine-free organometallic precursor.