Polyalkoxylated Polyalkyleneimine Additive for Void-Free Copper Electroplating
Solution Overview
Problem
Current copper electroplating technologies face challenges in achieving uniform metal deposits on substrates with small features, often resulting in defects like voids and seams, particularly in nanometer and micrometer-scale apertures.
Innovation Solution
The use of polyalkoxylated polyalkyleneimines as additives in copper electroplating baths, which provide a polyalkyleneimine backbone with N hydrogen atoms substituted by polyoxyalkylene radicals, offering improved leveling properties and reducing defects such as voids and seams.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional electroplating additives are used, then metal deposit can be achieved on substrate surface, but defects such as voids and seams form within the copper lines
Solution Approach 1:
The patent modifies the chemical structure of polyalkyleneimine by introducing polyoxyalkylene radicals at the N-terminal, changing the molecular weight to specific ranges (100-100,000 g/mol), and controlling the degree of substitution (0.1-2.0 radicals per nitrogen atom). These parameter changes optimize the additive's performance to eliminate defects while achieving uniform metal deposit in nanoscale features
Solution Approach 2:
The invention creates a composite structure by combining polyalkyleneimine backbone with polyoxyalkylene radical side chains. This composite molecular architecture integrates the beneficial properties of both components: the polyalkyleneimine provides metal ion complexation and deposition control, while the polyoxyalkylene radicals enhance leveling performance and reduce defects in high-aspect-ratio structures
2Manufacturing precision
If conventional leveling agents are used, then some leveling effect is achieved, but overplating occurs requiring post-deposition material removal
Solution Approach 1:
The patent optimizes molecular weight (100-100,000 g/mol) and polyoxyalkylene radical density (0.1-2.0 per nitrogen atom) to achieve precise control over copper deposition. This results in substantially planar copper layers with minimal overplating, reducing CMP material removal while maintaining high planarity
3Manufacturing precision
If electroplating is performed in nanometer and micrometer scale apertures, then feature filling is achieved, but defects like voids and seams form
Solution Approach 1:
The polyoxyalkylene radicals provide localized steric hindrance and electrostatic repulsion at the N-terminal, creating a protective effect that prevents defect formation specifically in high-aspect-ratio nanoscale features while maintaining uniform deposition across the entire substrate surface
Solution Approach 2:
The composite molecular structure of polyalkoxylated polyalkyleneimine combines the metal complexation capability of polyalkyleneimine with the defect-preventing properties of polyoxyalkylene radicals, achieving reliable void-free and seam-free filling of sub-100nm vias and trenches
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 results in substantially planar copper layers with reduced overplating and minimal defects, even on substrates with varying aperture sizes, enhancing the filling performance of small features and reducing the need for post-deposition material removal.
Implementation Method 1
composition for metal electroplating comprising leveling agent
Implementation Method 2
presence of organic substances as additives in the electroplating bath can be crucial in achieving a uniform metal deposit
Data Source
AI summary
A composition comprising a source of metal ions and at least one additive comprising a polyalkyleneimine backbone, said polyalkyleneimine backbone having a molecular weight Mw of from 300 g/mol to 1000000 g/mol, wherein the N hydrogen atoms in the backbone are substituted by a polyoxyalkylene radical and wherein the average number of oxyalkylene units in said polyoxyalkylene radical is from 1.5 to 10 per N—H unit.