Pd Catalyst Particle Size Control for TSV Plating Step Coverage
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Solution Overview
Problem
Conventional methods for forming metal layers on substrates, such as those used in LSI substrates and TSVs, face challenges with step coverage, high production costs, and difficulty in uniform film formation, especially for high aspect ratio via holes, due to limitations in physical deposition methods and the expense of chemical deposition methods.
Innovation Solution
A method using Pd particles with a size of 0.6 nm to 4.0 nm and a face-to-face dimension of the (111) plane of 2.254 Å or more as catalysts for electroless plating, supported by a colloidal solution and self-assembled monolayers, to enhance catalytic activity and adhesiveness, allowing for uniform and continuous film formation on substrates with high aspect ratio via holes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If physical deposition methods are used to form metal layers, then the process is simple and low cost, but step coverage is poor and large vacuum apparatuses are required
Solution Approach 1:
The invention changes the fundamental deposition mechanism from physical vapor deposition to electroless plating, utilizing chemical reduction reactions instead of physical deposition. This parameter change enables excellent step coverage while maintaining process simplicity and avoiding large vacuum equipment requirements
Solution Approach 2:
The invention introduces catalyst particles (such as Pd particles) as intermediaries to initiate and control the electroless plating process. These catalyst particles enable the chemical deposition reaction to occur selectively on substrate surfaces, achieving good step coverage without requiring complex vacuum apparatuses
2Manufacturing precision
If chemical deposition methods are used to form metal layers, then step coverage is satisfactory, but production cost increases due to expensive metal compounds and high temperature requirements
Solution Approach 1:
The invention optimizes the chemical deposition parameters by using electroless plating at lower temperatures with carefully controlled reagent concentrations. This reduces the need for expensive high-temperature equipment and energy consumption while maintaining satisfactory step coverage
Solution Approach 2:
The invention uses catalyst particles that can be applied in controlled amounts and potentially reused or regenerated, replacing the need for continuously adding expensive metal compounds. The catalyst particles enable the deposition process to proceed with lower concentrations of expensive metal salts
3Productivity
If conventional plating methods are used on high aspect ratio via holes, then film formation can occur, but uniform film formation is difficult to achieve
Solution Approach 1:
The invention uses catalyst particles as intermediaries that can penetrate and distribute uniformly throughout high aspect ratio via holes. These particles serve as nucleation sites for electroless plating, ensuring uniform metal film formation from the bottom up, overcoming the limitations of conventional plating methods
Solution Approach 2:
The invention performs preliminary catalyst particle deposition before the actual metal layer formation. This preliminary action ensures that catalyst particles are uniformly distributed throughout the via holes, setting the stage for uniform electroless plating and solving the film uniformity problem in advance
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 enables the formation of stable and uniform plating layers on substrates with high aspect ratio via holes, improving adhesiveness and allowing for efficient plating processing, even in challenging geometries, while reducing production costs by using Pd particles with controlled size and crystal plane dimensions.
Implementation Method 1
a method using Pd particles with a size of 0.6 nm to 4.0 nm and a face-to-face dimension of the (111) plane of 2.254 Å or more as catalysts for electroless plating
Implementation Method 2
supported by a colloidal solution and self-assembled monolayers, to enhance catalytic activity and adhesiveness
Data Source
Figure 1(a)~1(b)
Figure 2~3
Figure 4
AI summary
The present invention provides a method for treating a substrate that supports metal fine particles for forming a plating layer on a circuit pattern or TSVs in various substrates, in which further micronization treatment is enabled compared with the conventional methods, and the formation of a stable plating layer is enabled. The present invention is a method for treating a substrate, the method including bringing a substrate into contact with a colloidal solution containing metal particles in order to support the metal particles that serve as a catalyst for forming a plating layer on the substrate, in which the colloidal solution contains metal particles formed of Pd and having a particle size of 0.6 nm to 4.0 nm and a face-to-face dimension of the (111) plane of 2.254 Å or more. When an organic layer such as SAM is formed on a surface of the substrate before this treatment, the binding force of the Pd particles can be increased.