Electroless Plating Solution with Dual Borane Reducing Agents

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Solution Overview

Problem

Existing electroless plating solutions for semiconductor devices face challenges in achieving stable deposition rates and alloy composition when using single borane reducing agents, often resulting in unstable solutions and imbalanced deposition rates, which can lead to issues like high roughness and nodule formation.

Innovation Solution

A solution utilizing a combination of two borane containing reducing agents, where the first borane agent has a significantly higher deposition rate than the second, is used to stabilize the bath and control deposition rates, allowing for precise adjustment and maintaining alloy composition without nonborane reducing agents.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Device complexity

If a single borane reducing agent is used in electroless plating solution, then the solution formulation is simple, but the deposition rate becomes unstable and alloy composition cannot be controlled

Engineering Contradiction:

Improvesolution formulation complexityVSAvoiddeposition rate stability and alloy composition control

Core Design Contradiction:

Device complexityVSManufacturing precision

Solution Approach 1:

The patent combines two different borane reducing agents (typically borane-ammonia complex and borane-amine complex) in a single electroless plating solution. This merging of multiple reducing agents with different deposition rates allows the system to achieve stable overall deposition rates and controlled alloy composition that cannot be obtained with a single reducing agent alone.

Inventive Principle:

Principle #5Merging (Combining)

Solution Approach 2:

The patent changes the chemical parameters of the reducing agents by selecting borane compounds with different amine ligands. By adjusting the type and ratio of borane reducing agents, the deposition rate and alloy composition can be precisely controlled. The different borane agents provide complementary deposition characteristics that stabilize the overall process.

Inventive Principle:

Principle #35Parameter changes

2Ease of operation

If a single borane reducing agent is used, then the process is easy to operate, but high roughness and nodule formation occur

Engineering Contradiction:

Improveprocess operation simplicityVSAvoidsurface roughness and film quality

Core Design Contradiction:

Ease of operationVSManufacturing precision

Solution Approach 1:

By merging two borane reducing agents with different reactivities, the patent creates a balanced system where one agent provides stable baseline deposition while the other contributes to controlled growth. This combination prevents the high roughness and nodule formation that occur with single aggressive reducing agents, while maintaining operational simplicity.

Inventive Principle:

Principle #5Merging (Combining)

Solution Approach 2:

The patent applies local quality by having different borane reducing agents act at different rates and locations on the substrate surface. The less reactive borane agent provides uniform background deposition, while the more reactive agent contributes to specific growth zones, resulting in smooth, nodule-free surfaces with controlled morphology.

Inventive Principle:

Principle #3Local quality

3Productivity

If nonborane reducing agents are used, then deposition rate can be increased, but alloy composition control is lost and solution stability decreases

Engineering Contradiction:

Improvedeposition rateVSAvoidalloy composition control and solution stability

Core Design Contradiction:

ProductivityVSManufacturing precision

Solution Approach 1:

The patent changes the parameters of borane reducing agents by selecting different amine ligands and concentrations to achieve deposition rates comparable to nonborane agents. By optimizing the ratio and concentration of the two borane agents, the system achieves high productivity while maintaining the alloy composition control and solution stability inherent to borane-based chemistry.

Inventive Principle:

Principle #35Parameter changes

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 stabilizes the electroless deposition process, adjusts deposition rates effectively, and ensures low roughness and controlled film properties, enabling efficient and controlled metal layer deposition on semiconductor substrates.

Implementation Method 1

A first borane containing reducing agent is provided to the solvent. A second borane containing reducing agent is provided to the solvent, wherein the first borane containing reducing agent has a deposition rate of at least two times a deposition rate of the second borane containing reducing agent

Methodology Applied

Scientific EffectChemical reduction: Reduction

Data Source

PatentUS9818617B2Method of electroless plating using a solution with at least two borane containing reducing agents

Publication Date: 2017.11.14 LAM RES CORP

AI summary

A solution for providing electroless deposition of a metal layer on a substrate is provided. A solvent is provided. A metal precursor is provided to the solvent. A first borane containing reducing agent is provided to the solvent. A second borane containing reducing agent is provided to the solvent, wherein the first borane containing reducing agent has a deposition rate of at least five times a deposition rate of the second borane containing reducing agent, and wherein the solution is free of nonborane reducing agents.