Electroless Copper Plating Solution Using Diisopropanolamine Ligand
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Solution Overview
Problem
Existing electroless copper plating solutions have low deposition rates, typically not exceeding 10 μm/h at ambient temperature, which is insufficient for high-rate technological processes, and often require additional additives that complicate the deposition process.
Innovation Solution
A new electroless copper plating solution utilizing diisopropanolamine as a copper(II) ligand, which enables copper deposition rates of at least 30 μm/h at ambient temperature without the need for additional additives, maintaining solution stability and efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If traditional copper(II) ligands (EDTA, tartrate, Quadrol) are used in electroless copper plating solutions, then the plating process is stable, but the copper deposition rate is low (3-10 μm/h)
Solution Approach 1:
The patent changes the chemical nature of the copper(II) ligand from traditional agents (EDTA, tartrate, Quadrol) to a new class of ligands including diisopropanolamine, N-methyl diisopropanolamine, and their derivatives. This parameter change in ligand structure enables dramatically higher copper deposition rates (30-100 μm/h) while maintaining solution stability through the specific molecular properties of these new ligands.
2Productivity
If additional additives (accelerating and stabilizing agents) are added to increase plating rate, then copper deposition rate improves, but the process complexity increases
Solution Approach 1:
The patent extracts and eliminates the need for additional accelerating and stabilizing additives by incorporating their functions directly into the copper(II) ligand structure. The new ligands (such as diisopropanolamine and its derivatives) inherently provide both the stability function and the rate-enhancing function, simplifying the plating solution composition and process while achieving high deposition rates of 30-100 μm/h.
3Use of energy by moving object
If ambient temperature plating is used, then energy consumption is reduced, but copper deposition rate is insufficient for high-rate technological processes
Solution Approach 1:
The patent changes the chemical parameters of the plating solution, specifically using new copper(II) ligands with enhanced reactivity that enable high copper deposition rates (30-100 μm/h) at ambient temperature. This eliminates the need for thermal energy input while achieving productivity levels previously only attainable at elevated temperatures, thus reducing energy consumption without sacrificing deposition rate.
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 solution achieves significantly higher copper deposition rates, allowing for the deposition of at least 30 μm thick copper coatings in one hour, while maintaining solution stability and eliminating the need for additional additives, thus enhancing the efficiency and simplicity of the process.
Implementation Method 1
electrons appearing during the anodic oxidation of the reducing agent reduce copper (II) ions to metallic copper on the surface to be plated
Implementation Method 2
complexing agents forming stable copper(II) complexes are needed with the aim to prevent precipitation of copper(II) hydroxide
Data Source
AI summary
An electroless copper plating solution is disclosed herein. The solution includes an aqueous copper salt component, an aqueous solution of formaldehyde, an amine based complexing agent, and mixture of alkaline pH modifying substances in an amount sufficient to make the electroless plating solution alkaline. A method of preparing an electroless copper plating solution is also provided.