The sealing of carrier tape and cover tape is the core step to realize the basic functions of electronic packaging. It also undertakes irreplaceable functions such as ESD protection, precision transport, and feeding. Meeting these stringent functions imposes many restrictions on the materials used, leading to issues like "sealing cracks". However, with the right methods, this problem is avoidable.
1. The Essence of the Problem: Material Incompatibility
The root cause of sealing cracks lies in the **mismatch** between the carrier tape and cover tape materials. There are differences in the basic materials of the two products:
- Carrier Tape Raw Materials: Common ones include PC, PS, ABS, etc.
- Cover Tape Base Material: Generally PET (Polyester).
Due to differences in chemical composition or melting points, carrier tapes and cover tapes are inherently incompatible. This difference makes natural adhesion difficult, easily leading to peel forces that are too light (prone to cracking) or too heavy (difficult to peel), failing to meet the SMT peel standards.
2. Chain Reaction Caused by Manufacturing Formula Differences
To achieve compatibility, chemical additives are introduced into the cover tape manufacturing process or combined with certain chemical materials. However, different carrier tape manufacturers have different habits in formulations and adding conductive particles, leading to vastly different results when bonding with the same cover tape.
Since packaged components differ, the required post-sealing peel force also varies, so it cannot be generalized and requires targeted solutions.
3. Solution Strategy: Testing & Standardization
To thoroughly solve the sealing crack problem, the core method is through **compatibility testing**:
- Compatibility Test: Strict testing of both products must be ensured to find compatible specifications.
- Aging Test: After simulating different external environments (such as high temperature and humidity), aging tests should be conducted at different times to verify the long-term stability of sealing strength.
- Process Fixation: It is essential to guarantee the **singularity** of compatible cover tape and carrier tape after testing, as well as the **fixation** of sealing conditions, ensuring safe and stable production line operation.