If you’re involved in semiconductor processing, you’ve probably come across the term “Plating” more than once.
But what exactly is the plating process, and why is it so essential—especially when it comes to copper wiring in semiconductors?
Let’s break it down in simple, practical terms.
What Is the Plating Process?
In the semiconductor world, Plating refers to a technique used to deposit a metal layer—typically copper (Cu)—on the surface of a wafer.
It’s most commonly done through electroplating, where metal ions in a chemical bath are reduced onto the wafer by applying electric current.
This process is vital because copper, while offering excellent conductivity, cannot be easily deposited using typical PVD or CVD techniques—especially when a thick, uniform metal layer is required.
That’s where plating becomes the preferred method.
Why Is Plating Necessary?
Modern semiconductor devices demand extremely dense and low-resistance wiring structures.
A thin film isn’t enough. We need thick and uniform copper layers to build reliable interconnects.
The plating process enables this by:
-
Creating thick copper lines for wiring
-
Filling high aspect-ratio features like TSVs (Through-Silicon Vias)
-
Supporting redistribution layers and bump formation in advanced packaging
So, whether you’re working with logic chips, memory, or 3D ICs, plating plays a critical role in backend-of-line (BEOL) processing.
Where Is Plating Used in the Semiconductor Process?
Plating is typically applied in the BEOL phase, after dielectric layers have been formed and etched.
Common use cases include:
-
Copper interconnects in multilayer metal stacks
-
TSV (Through-Silicon Via) filling for 3D packaging
-
Bump formation for flip-chip or wafer-level packaging
-
Redistribution Layer (RDL) formation
Key Metrology Tools for Plating Quality Control
Ensuring high-quality plating requires precise measurement of thickness, surface profile, and electrical performance.
Here are three essential tools we actively use to maintain plating quality:
1. Ellipsometer
Used before plating to evaluate thin seed layers.
It provides non-contact, nanometer-level measurements of film thickness and uniformity across the wafer.
2. Four-Point Probe
After plating, we use this to measure sheet resistance, which is directly related to electrical conductivity.
A stable resistance value is a good indicator of uniform, defect-free copper plating.
3. White Light Interferometer (WLI)
This non-contact tool is ideal for measuring surface height and roughness—especially in bump or TSV plating, where vertical profiles matter.
WLI gives high-resolution 3D surface maps that help spot issues early.
Final Thoughts
To sum up:
-
Plating is a vital technique in modern semiconductor manufacturing, especially for thick, conductive copper layers.
-
It is widely used in BEOL, TSV, bump formation, and advanced packaging.
-
For process control, tools like the Ellipsometer, Four-Point Probe, and WLI are indispensable.
We’re Here to Help
We warmly welcome any inquiries regarding product specifications or pricing.
With English-speaking staff on our team, we’re well-prepared to assist you efficiently and clearly.
Please don’t hesitate to contact me directly — I will personally respond to your email.
You can reach me at: hy.kang@kovistek.com