Ovens Suitable for BGA Chip Baking

BGA (Ball Grid Array) chips, as high-performance integrated circuits widely used in electronic devices, have complex and delicate structures. During storage, transportation, or production, BGA chips are prone to absorbing moisture from the air. When a damp chip is subjected to high-temperature processes such as soldering, the internal moisture will rapidly vaporize and expand, causing the chip to swell and deform. This not only directly damages the chip but also leads to internal defects such as cracking, delamination, peeling, and micro-cracks, affecting the chip's performance and lifespan. Baking BGA chips to remove internal moisture is a crucial step to ensure their stable and reliable performance in subsequent processes.

Purpose of Baking BGA Chips

1.Moisture Removal: BGA chips are susceptible to absorbing moisture from the environment during manufacturing, transportation, and storage. If not removed, the moisture will rapidly vaporize and expand during reflow soldering, generating significant stress that can cause the chip package to crack, solder joints to fail, or internal circuits to be damaged. Baking allows the moisture inside the chip to evaporate gradually, reducing the potential risks during soldering.

2.Enhancing Soldering Quality: During the baking process, oxides and contaminants on the chip surface will be reduced along with the evaporation of moisture, improving the solderability of the chip's pins. This enables the solder to bond better with the pins, enhancing the quality and reliability of the soldering. Dry chips form better solder joints during soldering, with the solder wetting the pads and chip pins more effectively, reducing defects such as cold soldering and false soldering, and improving the electrical and mechanical performance of the soldering.

3.Improving Chip Reliability: Removing moisture can slow down the rate of internal chemical reactions in the chip, such as corrosion and leakage between metallization lines, reducing the risk of chip failure and enhancing stability and reliability during long-term use. Baking also allows the molecular structure of the materials inside the chip to realign, releasing stress and preventing chip cracking, thereby improving mechanical properties.

Standard Baking Process for BGA Chips

1.Baking Standards

Depending on the moisture sensitivity level (MSL) of the BGA chips, the required baking temperature and duration vary. For BGA chips that have exceeded the control period, have failed vacuum packaging, have humidity indicator cards exceeding the specified limits after vacuum packaging is opened, or are in bulk without vacuum packaging, they typically need to be baked at 125℃±5℃ for 24 hours. For other cases, such as main chips (BGA) of all customers within the control range, baking is performed at 120℃±5℃ for 6 hours. It is important to note that if multiple baking cycles are required, the total baking time must not exceed 96 hours.

2.Baking Process

• Preheating Stage: Preheat the oven to the set temperature to ensure uniform temperature distribution.
  
• Baking Stage: Place the BGA chips into the oven and bake them according to the specified temperature and duration.
  
• Cooling Stage: After baking is complete, the chips should be cooled down slowly to avoid thermal stress caused by sudden temperature changes that could damage the chips. The cooling rate should generally be controlled between 5℃ and 10℃ per minute.
  
• Monitoring and Recording: During the baking process, real-time monitoring of parameters such as temperature and time is necessary to ensure that the baking process meets the process requirements and to record all parameters during the baking process.

Applications of BGA Chip Baking

• Electronics Manufacturing Industry: In the production of electronic products such as computers, mobile phones, tablets, and servers, BGA chips, as core components, are usually baked before soldering to ensure soldering quality and improve product yield and reliability.
• Semiconductor Packaging and Testing Industry: During the chip packaging process, to prevent moisture damage, BGA chips need to be baked before and after packaging. Baking during storage and transportation can also prevent chips from getting damp.
• Electronics Repair Industry: When repairing circuit boards containing BGA chips, such as replacing chips or repairing faulty circuit boards, the circuit board and chips need to be baked first to remove moisture before soldering. This prevents moisture-related issues during repair that could lead to poor soldering or chip damage.
  
• Aerospace, Automotive Electronics, and Other High-Reliability Fields: In these fields, the reliability of electronic products is extremely important. BGA chips must undergo strict baking treatment before use to ensure normal operation in harsh environments and to prevent chip failures that could cause safety accidents.

Applicable Ovens for Baking BGA Chips

1.Nitrogen-filled oven: By introducing nitrogen into the oven, the oxygen content is reduced, thereby minimizing oxidation reactions. This type of oven is suitable for chips that are sensitive to oxidation and can effectively protect the chip surface from oxidation. Its characteristics include the ability to provide a low-oxygen environment, reducing the risk of oxidation during high-temperature baking, although the equipment and operating costs are relatively high.

2.High-temperature oven: Suitable for short-duration baking at higher temperatures. These ovens typically feature rapid heating and cooling capabilities, which can improve baking efficiency. They are characterized by their ability to quickly reach the required high-temperature environment, making them suitable for BGA chips with shorter baking time requirements.

3.Clean Oxygen-free oven: Particularly suitable for chips with extremely high baking environment requirements, such as precision electronic components and semiconductor chips. This type of oven creates a high-temperature, low-oxygen, and clean baking environment by introducing inert gases (such as nitrogen), effectively preventing contamination and oxidation of the chips during baking. It is characterized by its ability to provide a highly clean and low-oxygen baking environment, ensuring that chips are not contaminated during the baking process.

4.Vacuum Oven: By evacuating the oven to reduce the internal pressure, the evaporation of moisture and decomposition of organic substances are accelerated. Vacuum ovens are suitable for situations where it is necessary to remove organic contaminants from inside the chips or to improve baking efficiency. They are characterized by their ability to achieve efficient baking at lower temperatures, reducing the potential damage of high temperatures to the chips.

5.Hot Air Circulation Oven: One of the most common baking devices currently in use. By circulating hot air within the oven, heat distribution is made more uniform, ensuring that BGA chips are evenly heated and improving the baking effect. These ovens have high temperature control accuracy, can meet the temperature requirements for SMT component baking, and have a large capacity, making them suitable for large-batch BGA chip baking.

Baking BGA chips is a critical process to ensure performance and reliability. By removing moisture from inside the chips through baking, various defects caused by moisture vaporization during soldering are effectively prevented, soldering quality is improved, and the mechanical and electrical properties of the chips are enhanced. Whether in electronics manufacturing, semiconductor packaging and testing, electronics repair, or high-reliability fields such as aerospace and automotive electronics, baking is essential. In actual operations, appropriate oven equipment should be selected based on different situations, and baking standards and processes should be strictly followed to ensure the stability and reliability of chips in subsequent processes, thereby improving the overall quality and performance of electronic products.