Copper-Nickel Seed Layer for Plating Adhesion
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Solution Overview
Problem
Conventional plating processes for forming silicon-through electrodes in semiconductor components often result in peeling issues between layers, leading to reduced reliability of the plating process and the manufactured components.
Innovation Solution
A plating method involving the formation of a second electroless plating layer made of a copper-nickel alloy on a first electroless plating layer, which serves as a seed layer for subsequent copper electrolytic plating, enhancing adhesion and reducing stress between layers.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a single film of copper is electrolessly plated on the surface of the barrier layer, then the seed layer is formed, but peeling between the barrier layer and seed layer occurs
Solution Approach 1:
The copper seed layer is divided into two distinct layers: a first copper layer directly on the barrier layer, and a second copper layer on top of the first copper layer. This segmentation allows each layer to serve specific functions - the first copper layer ensures strong adhesion to the barrier layer, while the second copper layer provides the necessary electrical conductivity and seed function for subsequent electroplating processes.
Solution Approach 2:
The invention uses a composite structure consisting of the barrier layer (Co-W-B alloy), first copper layer, and second copper layer. This multi-material composite approach leverages the complementary properties of each material - the barrier layer's diffusion suppression capability, and the copper layers' electrical conductivity and adhesion properties, to achieve both easy manufacture and high reliability.
2Ease of manufacture
If copper is electroplated on the seed layer to form the silicon-through electrode, then the electrode is formed, but peeling occurs between the electrode and substrate
Solution Approach 1:
The electrode structure is segmented into multiple layers: barrier layer, first copper layer, and second copper layer. This segmentation ensures that each layer contributes to preventing peeling - the barrier layer prevents copper diffusion into the substrate, while the first copper layer provides strong adhesion to the barrier layer, collectively preventing electrode peeling from the substrate.
Solution Approach 2:
The barrier layer and first copper layer are formed beforehand as cushioning layers to prevent peeling of the subsequently formed electroplated copper electrode. These pre-formed layers provide a stable foundation that compensates for potential adhesion issues that might occur during electroplating, ensuring long-term reliability of the electrode-substrate bond.
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 effectively suppresses peeling between plating layers, thereby improving the reliability of the plating process and the resulting components by reducing film stress and enhancing adhesion between the barrier and seed layers.
Implementation Method 1
forming, by electroless plating, a second electroless plating layer made of a copper alloy on a surface of a first electroless plating layer which is formed by electroless plating
Implementation Method 2
forming, by electroless plating, a second electroless plating layer made of a copper alloy on a surface of a first electroless plating layer which is formed by electroless plating
Data Source
AI summary
Reliability of a plating process and reliability of a component manufactured through the plating process can be improved by suppressing peeling between plating layers formed by electroless plating. In a plating method, a plated component manufactured by the plating method, and a plating system 1 configured to manufacture the plated component by the plating method, a second electroless plating layer 39, which is made of a copper alloy and formed by the electroless plating, is formed on a surface of a first electroless plating layer 38 formed by the electroless plating. The first electroless plating layer 38 is a barrier layer configured to suppress diffusion of copper and is made of cobalt or a cobalt alloy. The second electroless plating layer 39 is a seed layer for forming an electrolytic plating layer of copper on a surface thereof and is made of an alloy of copper and nickel.