Alloy Film Substrate for Uniform Electroless Plating
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Solution Overview
Problem
The existing methods for forming ultrafine copper wiring in ULSI technology face challenges in achieving uniformity and coverage with a two-layer structure of barrier and catalytic metal layers, which complicates the process and is difficult to apply to thin film requirements.
Innovation Solution
A substrate with an alloy film formed by chemical vapor deposition (CVD) combining metal elements like tungsten, molybdenum, or niobium for barrier function and ruthenium or platinum for catalytic power, with a content ratio of 5-90 at.%, enabling a single layer that combines barrier and catalytic properties for electroless plating.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a two-layer structure of barrier layer and catalytic metal layer is formed, then the barrier function and catalytic function are provided, but the process complexity increases and film thickness becomes too thick for ultrafine wiring
Solution Approach 1:
The patent combines the barrier layer and catalytic metal layer into a single alloy film layer. This alloy film simultaneously provides both the barrier function (preventing copper diffusion) and the catalytic function (enabling electroless plating), thereby eliminating the need for a two-layer structure and reducing overall film thickness for ultrafine wiring applications
Solution Approach 2:
The alloy film is designed to perform multiple functions simultaneously: it acts as both a barrier layer (preventing copper diffusion into the substrate) and a catalytic layer (providing catalytic activity for electroless copper plating). This multi-functional design simplifies the overall structure while maintaining all necessary functions for ultrafine copper wiring formation
2Shape
If electroless copper plating is performed on a mirror finish surface, then the substrate surface is smooth, but the reactivity is low and uniform plating is difficult
Solution Approach 1:
The alloy film introduces localized catalytic activity at the molecular level within the film structure. This creates specific active sites for copper deposition while maintaining overall surface smoothness, enabling uniform plating on mirror finish surfaces by distributing catalytic activity evenly throughout the film rather than requiring surface roughness
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 improves film uniformity and coverage, reduces the thickness of the seed layer, and enhances the formation of fine semiconductor wiring with low electric resistance, overcoming the limitations of traditional two-layer structures and ensuring good adhesion to the substrate.
Implementation Method 1
an alloy film of one or more metal elements, having a barrier function, selected from among tungsten, molybdenum, and niobium and a metal element or metal elements, having catalytic power with respect to electroless plating, composed of ruthenium and/or platinum, formed by chemical vapor deposition (CVD)
Implementation Method 2
a metal element or metal elements, having catalytic power with respect to electroless plating, composed of ruthenium and/or platinum
Data Source
AI summary
A layer having a barrier function and catalytic power and excelling in formation uniformity and coverage of an ultrathin film, a pretreatment technique making it possible to form an ultrafine wiring and form a thin seed layer of uniform film thickness and a substrate including a thin seed layer formed with a uniform film thickness by electroless plating by using the aforementioned technique. A substrate in which an alloy film of one or more metal elements, having a barrier function and a metal element or metal elements, having catalytic power with respect to electroless plating is formed by chemical vapor deposition (CVD) on a base to a film thickness of 0.5 nm to 5 nm with a content ratio of the one or more metal element having a barrier function from 5 to 90 at. %.