Baking Process for Taped Plastic-Packaged Components
In the electronics manufacturing industry, taped packaging is a common form of component delivery, covering resistors, capacitors, SMD ICs, transistors, terminals, and many other types of electronic parts. For plastic-encapsulated integrated circuits and various sensitive components, the packaging materials themselves are hygroscopic and can easily absorb moisture from the environment during storage and transportation. When such moistened components enter the surface-mount assembly process and pass through high-temperature reflow soldering, the internal moisture will rapidly vaporize and expand. If the stress generated by this internal water vapor exceeds the strength limit of the packaging material, it can cause internal cracking, delamination, damage to gold wire bond points, or even the “popcorn effect,” leading to soldering failure and significant degradation in product reliability. Therefore, performing proper baking and dehumidification on moistened taped plastic-packaged components prior to placement is a critical process step to ensure SMT soldering quality and product reliability.
Ⅰ. Functions of Baking Taped Plastic-Packaged Components
1.Removing Internal Moisture and Preventing Popcorn Effect Risks
Baking is the most effective method for removing moisture. By placing components in an appropriately high-temperature environment, moisture absorbed within the package is accelerated in diffusion and escapes, reducing the component’s moisture absorption level to a safe range. This is essential for preventing encapsulation cracking, delamination, and similar failures during reflow soldering.
2.Improving Soldering Quality and Enhancing Solderability
Beyond internal moisture, trace amounts of water and volatile contaminants adsorbed onto the leads can also affect solder performance. Baking effectively removes these undesirable factors, allowing solder to wet pads and leads more thoroughly, thereby improving soldering quality and reducing defects such as cold solder joints or false welds.
3.Restoring Floor Life of Components
Every MSD (Moisture Sensitive Device) has a specific moisture sensitivity level (MSL) and corresponding allowable exposure time in the production environment. Once this exposure limit is exceeded, the device is no longer safe for direct assembly. Following IPC/J-STD-033 standards for baking restores the original floor life of the component, ensuring continued reliability in subsequent assembly processes.
4.Extending Storage Life and Reducing Material Scrap Costs
For taped packaging formats—especially moisture-sensitive devices such as ICs and sensors—baking can restore components that have absorbed moisture or exceeded their storage period back to usable condition, avoiding unnecessary losses from scrapping materials.
Ⅱ. Baking Process for Taped Plastic-Packaged Components
1.Temperature and Time Settings
For taped plastic-packaged components, low-temperature (40°C) long-duration baking is recommended. Although time-consuming, it effectively protects the integrity of the plastic packaging material, preventing deformation of carrier tape and cover tape. If production schedules require shorter baking times, components must first be removed from the tape and transferred into high-temperature-resistant trays (e.g., high-temp tray carriers), then baked at 125°C or 90°C. After baking, components must be re-taped or manually placed. It should be noted that removing parts from tape and re-taping increases risks of mechanical damage and electrostatic discharge (ESD); operators must wear anti-static wrist straps, gloves, and work on ESD-safe benches.
2.Pre-Baking Preparation
Paper and plastic containers (such as cardboard boxes, bubble wrap, plastic wraps) must be removed before baking. Rubber bands or binding straps on plastic reels must also be taken off to prevent melting or emission of harmful gases under high temperatures. Components should be placed in a single layer on clean baking trays, with adequate spacing between them to ensure free air circulation and avoid uneven heating caused by stacking.
3.Baking Environment Control
The baking process should occur in a dry, clean environment; the relative humidity inside the oven should be maintained at a low level to prevent re-absorption of moisture during baking. After baking, unused components must be quickly transferred to a dry cabinet (≤10% RH) or resealed in vacuum packaging with fresh desiccant and humidity indicator cards to maintain dryness.
4.Cooling and Post-Baking Handling
After baking, components should be cooled naturally inside the oven until near room temperature (typically below 40°C) before removal, avoiding thermal shock or re-absorption of moisture due to rapid cooling. Once removed, they should be soldered within the specified time frame; if immediate use is not possible, they must be returned to dry storage.
Ⅲ. Ovens Applicable to Taped Plastic-Packaged Components
Several oven types are commonly used for baking taped plastic-packaged components:
1.Hot Air Circulation Oven
Equipped with internal fans for forced air convection, ensuring uniform temperature distribution (typically ±2°C tolerance). Suitable for precision components requiring consistent heating, and available in large capacities for batch processing. Airflow design should be selected carefully to prevent direct hot air from deforming tapes.
Filled with high-purity nitrogen during baking to create an inert atmosphere, preventing oxidation of leads and pads at high temperatures. The low-humidity nature of nitrogen accelerates moisture evaporation, making it suitable for precious-metal-plated devices or high-reliability products. Nitrogen also improves thermal conductivity, shortens baking time, and reduces thermal aging of plastic tapes.
By evacuating air to create a negative pressure environment, moisture can boil and vaporize at lower temperatures, greatly shortening baking duration or lowering required temperatures. For taped plastic-packaged components, vacuum conditions allow efficient dehydration at 90°C or even lower, completely avoiding heat deformation of carrier tapes and reels. Ideal for high MSL grades, thick packages, or applications where tape integrity is critical.
Equipped with HEPA filtration systems to maintain Class 100 or Class 1000 cleanliness levels, preventing micro-particle contamination during baking. Suitable for high-reliability sectors such as medical electronics and aerospace.
5.Oven Selection Considerations
Selection must account for the component’s moisture sensitivity level, package size and thickness, tape material’s thermal resistance, production volume, and quality requirements. Regardless of type, ovens must be fitted with calibrated temperature sensors and humidity monitoring devices to ensure process traceability and consistency. Periodic verification of temperature uniformity is necessary to avoid hot or cold spots that could lead to inadequate baking or component damage.
Baking taped plastic-packaged components is a crucial procedure in electronics manufacturing. Whether for new material introduction, inventory recovery, or rework operations, any risk of moisture exposure warrants strict adherence to baking standards. The fundamental purpose is to fully remove accumulated moisture within the package through scientifically controlled temperature and time parameters, eliminating fatal defects such as popcorn effect and delamination during reflow soldering, relieving internal stress, stabilizing material properties, and providing a solid foundation for subsequent soldering processes.