The sealing of carrier tape and cover tape is the most basic function of electronic packaging. As packaging for SMD electronic components, it also undertakes irreplaceable functions such as ESD protection and transport. Meeting these multiple functions brings many restrictions to the materials used, leading to issues like "sealing cracks".
1. Root Cause: Material Mismatch
The fundamental reason for sealing cracks is the mismatch between the carrier tape and the cover tape. We need to understand the basic material properties:
- Carrier Tape: Common materials are PC (Polycarbonate), PS (Polystyrene), ABS, etc.
- Cover Tape: The base material is usually PET (Polyester).
Due to differences in chemical composition and melting points, carrier tapes and cover tapes are inherently incompatible. This makes natural bonding difficult, leading to overly tight or loose sealing, resulting in peel forces that are either too light or too heavy, failing to meet standard requirements.
2. Solution: Chemical Modification & Additives
To achieve compatibility and stable sealing, specific chemical additives are introduced during the cover tape manufacturing process, or it is combined with certain chemical materials.
However, different carrier tape manufacturers use different formulas (e.g., conductive particles). Therefore, the same cover tape may perform very differently when bonded with carrier tapes from different manufacturers.
3. Our Recommendation: Testing & Matching
We always emphasize: Not all cover tapes can be arbitrarily paired with any carrier tape. Moreover, different components have different requirements for peel force.
The only effective way to solve sealing crack problems is through compatibility testing:
Strict testing of both products is mandatory, simulating different external environments (e.g., high temperature and humidity) and conducting aging tests at different time points. Only by finding compatible specifications and fixing the sealing conditions (temperature, pressure, speed) can production stability be ensured.