How ITO Glass is Made: Sputtering & Coating Process

ITO (Indium Tin Oxide) glass is a special type of glass that conducts electricity while staying transparent. It’s used in touchscreens, smartphones, solar panels, and smart windows. But how is it made? The key process is called sputtering, a high-tech coating method.

Preparing the Glass

• Before coating, the glass must be super clean. Any dust or dirt will ruin the coating.
• The glass is washed with chemicals and then treated with ultrasound.
• It’s dried in a dust-free environment.

The Sputtering Process (How ITO is Added to Glass)

Sputtering is like spray-painting electricity onto glass, but instead of paint, we use tiny particles of indium tin oxide (ITO).

How Sputtering Works:

Vacuum Chamber Setup:

The glass is placed in a vacuum chamber (air is sucked out to prevent contamination).

Target Material (ITO Disc): –

A disc made of indium tin oxide (90% indium, 10% tin) is placed inside.

Plasma Creation: A gas (usually argon) is pumped in, and electricity is applied, turning it into plasma (charged particles).

Ion Bombardment: The plasma ions smash into the ITO disc, knocking off tiny ITO particles.

Deposition on Glass: The freed ITO particles fly and stick to the glass, forming a thin, conductive layer.

Heat Treatment (Annealing)

After sputtering, the glass is heated (annealed) to:

• Make the ITO layer more conductive.
• Improve adhesion (so it doesn’t peel off).

Quality Testing

Before use, the ITO glass is checked for:

• Thickness (usually 100-300 nanometers – thinner than a human hair!).
• Transparency (must let light through, like normal glass).
• Electrical Resistance (should conduct electricity well).

Why Sputtering?

• Precise control over thickness.
• Uniform coating (no streaks or gaps).
• Works at lower temperatures (good for delicate glass).

Other Coating Methods (Alternative to Sputtering)

• Chemical Vapor Deposition (CVD) – Uses gas reactions to deposit ITO.
• Spray Pyrolysis– Spray a liquid ITO solution and heat it.
• Pulsed Laser Deposition (PLD)– Uses lasers to vaporize ITO onto glass.
• But sputtering is the most common because it’s reliable and high-quality.

Final Product: ITO Coated Glass Slides!

Now, the glass has:

• Transparency (like normal glass).
• Conductivity (can carry electricity).
• Durability (resists scratches and wear).
• It’s ready for use in smartphones, TVs, solar panels, and more!