Surface Resistivity: Practical Applications in Plastics for the Semiconductor Industry

One of the most important electrical properties used to compare plastic materials for the semiconductor industry is surface resistivity.

Surface resistivity measures a material’s resistance to electrical current along the surface of the material. In contrast, volume resistivity (less commonly used for plastics) measures the resistance to current leakage through the body of the material.

In semiconductor manufacturing, materials must manage electromotive forces—especially static electricity. These materials, collectively referred to as ESD (Electro-Static Discharge) materials, are classified by their surface resistivity ranges:

• Conductive: 10¹ to 10⁴ Ω/sq — High current absorption, easily conducts electricity.
• Static Dissipative: 10⁵ to 10⁹ Ω/sq — Gradually drains or absorbs static charges.
• Anti-Static: 10¹⁰ to 10¹² Ω/sq — Prevents buildup of initial static charge.

Understanding Surface Resistivity Through Ohm’s Law

To understand surface resistivity, it helps to understand Ohm’s Law, which defines the relationship between voltage (V), current (I), and resistance (R):

V = I × R   →   Resistance (R) = Voltage (V) / Current (I)

• Current (I): The flow of electricity, measured in Amps (A).
• Voltage (V): The electrical potential difference or “pressure” pushing the current.
• Resistance (R): Opposition to current flow, measured in ohms (Ω).

A good analogy: Think of current like water in a hose. The flow rate = current, water pressure = voltage, and hose diameter = resistance. Choosing the correct plastic material is like selecting the right hose diameter for safe discharge control.

Applications of ESD Materials in the Semiconductor Industry

ESD plastic materials are used in many critical semiconductor applications:

• Inside process tools to protect wafers from static discharge
• In IC chip testing environments to protect sensitive components
• For clean room applications where static can attract dust particles
• As static-dissipative flooring in semiconductor fabs

Managing static discharge isn’t just about material selection—it’s about protecting sensitive electronics and improving yield in high-performance semiconductor environments.

It’s helpful to have an ESD expert to help manage your spark!

Need help selecting the right plastics for semiconductor applications?
Contact your local Port Plastics sales office or visit www.PortPlastics.com.