Modified Liner Thickness Uniformity in IC Interconnects
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Solution Overview
Problem
Conventional methods for forming liners in back-end-of-the-line interconnect structures in integrated circuits often result in non-conformal liners, leading to discontinuity issues and uneven thickness, which can increase resistance.
Innovation Solution
A method involving a selectively reactive gas is used to react with the liner-forming material on a porous interlayer dielectric layer, forming a converted expanded portion that increases the liner's thickness uniformly, addressing local thinness while preventing excessive thickness in other areas.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If additional liner-forming material is deposited to increase the thickness of locally thinned areas, then the thickness of thin areas is improved, but other portions of the liner become too thick which increases resistance
Solution Approach 1:
The patent applies local quality by selectively modifying the liner thickness at specific locations through a targeted process. The liner is selectively removed or etched at corners and other portions where it is too thick, while leaving the thickness at vertical walls and other areas unchanged. This localized modification approach allows thickness uniformity to be improved without uniformly increasing the liner thickness everywhere, thereby avoiding the resistance increase that would result from universal thickening.
2Ease of manufacture
If conventional deposition methods are used to form the liner, then the manufacturing process is simple, but the liner is non-conformal and locally too thin causing discontinuity issues
Solution Approach 1:
The patent applies preliminary action by first forming the liner using conventional deposition methods to achieve good conformality at vertical walls, then subsequently performing a selective removal step at specific locations (corners and other portions) where the liner is too thick. This two-step approach ensures that the liner is first properly formed with good conformality, then locally adjusted to achieve uniform thickness, thereby resolving the discontinuity issues without sacrificing the ease of the initial deposition process.
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
The method produces a more conformal and uniformly thickened liner, reducing discontinuity issues and improving the interconnect structure's conductivity by ensuring even thickness across the liner.
Implementation Method 1
A selectively reactive gas is advanced through the porous ILD layer for contact with the ILD facing surface at reaction conditions effective to react a portion of the liner with the selectively reactive gas to form a converted expanded portion
Data Source
AI summary
Integrated circuits and methods for fabricating integrated circuits are provided. In one example, a method for fabricating an integrated circuit includes contacting a liner that is disposed adjacent to a porous interlayer dielectric (ILD) layer of dielectric material with a selectively reactive gas at reaction conditions. A portion of the liner is reacted with the selectively reactive gas to form a converted expanded portion that is disposed between a remaining portion of the liner and the porous ILD layer.