What is Cover Tape?

Cover tape is a tape product used in electronic packaging, which must be used in conjunction with carrier tape. It typically uses polyester (PET) or polypropylene (PP) film as a base, coated with various functional layers (e.g., anti-static, adhesive). Under external force or heat, the cover tape seals the surface of the carrier tape, forming a closed space to protect electronic components in the pockets from falling out or damage during transport and storage.

To evaluate whether a cover tape is qualified, mainly look at the following four core performance indicators:

1. Peel Force

Peel force is the most critical technical indicator of cover tape. During the SMT placement process, the placement machine needs to peel the cover tape off the carrier tape so that the robotic arm can pick up the components from the pockets and mount them onto the circuit board.

Why it matters: To ensure precise positioning by the robotic arm, components must not jump or flip at the moment of peeling. Therefore, the peel force must be kept within an extremely stable range (usually between 30g-100g). As component sizes shrink (e.g., 0201, 01005), the requirement for peel force stability has reached unprecedented heights.

2. Optical Properties

Optical properties mainly include Haze, Transmittance, and Clarity.

Application Scenario: Modern automated production lines often use Automated Optical Inspection (AOI) systems to observe component markings, QR codes, or pin status directly through the cover tape. Therefore, high-quality cover tape must have good transmittance and low haze to ensure accurate machine vision recognition.

3. Surface Resistance (ESD)

To prevent electronic components (especially sensitive semiconductor chips) from being adsorbed onto the cover tape by static electricity (causing component loss) or damaged by electrostatic discharge, the cover tape surface must generally have anti-static functions.

Standard Requirement: The anti-static level is represented by surface resistance. Industry standards generally require the surface resistance of cover tape to be controlled between 10E9 - 10E11 Ω (Ohms), classified as static-dissipative material.

4. Tensile Properties

Tensile properties include Tensile Strength and Elongation.

• Tensile Strength: The maximum stress a sample can withstand before breaking, usually expressed in N/mm or MPa. High-strength cover tape prevents breakage during high-speed sealing or peeling.
• Elongation: The maximum percentage of deformation a material can withstand before breaking. Appropriate elongation ensures the cover tape has certain toughness and is not brittle.