What Are the Cleaning Methods for Semiconductor Material Boxes? Application and Advantages of Ultrasonic Cleaning Machines

In semiconductor manufacturing, material boxes (also known as wafer boxes or carrier boxes) are essential for storing and transporting wafers. Given the high cleanliness requirements in semiconductor production, the cleanliness of material boxes directly impacts the production yield of wafers.

What Are Semiconductor Material Boxes and Their Functions?

Semiconductor material boxes are specially designed containers for storing and protecting wafers, serving the following purposes:

1. Protecting Wafers

   During production and transportation, material boxes prevent external contaminants (e.g., dust, particles, chemicals) from coming into direct contact with wafers.

2. Preventing Damage

   The material boxes are designed with secure structures that effectively protect wafers from damage caused by vibrations or collisions.

3. Enhancing Efficiency

   The standardized structure of material boxes facilitates precise handling and transfer in automated equipment, improving production line efficiency.

Why Do Semiconductor Material Boxes Need Cleaning?

1. Particle Contamination

   During repeated use, material boxes can accumulate particles inside. If these particles transfer to the wafer surface, they may cause circuit shorts or opens.

2. Chemical Residues

   Material boxes may come into contact with various chemicals, leaving residues that could volatilize during high-temperature processes and contaminate wafers.

3. Static Adsorption

   Material boxes are typically made of polymer plastics that easily generate static electricity, attracting airborne microparticles. Regular cleaning is necessary to minimize this risk.

Ultrasonic Cleaning Machines: Performance and Advantages in Cleaning Material Boxes

Ultrasonic cleaning machines use high-frequency vibrations and cavitation effects in liquids to clean particles and chemical residues from material boxes. The advantages include:

1. Deep Cleaning

   Ultrasonic waves reach every corner of the material box, thoroughly cleaning grooves and hard-to-reach micro gaps.

2. Non-Damaging Cleaning

   As material boxes are often made of polymer materials, traditional mechanical cleaning might cause scratches. Ultrasonic cleaning uses a non-contact method, preventing surface damage.

3. Efficient Cleaning

   Multiple material boxes can be cleaned in a single cycle, typically within 5-10 minutes, greatly improving efficiency.

4. Eco-Friendly Features

   Ultrasonic cleaning requires minimal use of harsh chemicals, working effectively with mild alkaline or neutral cleaning solutions, thus reducing environmental pollution.

Comparison with Other Cleaning Methods

1. Spray Cleaning

• Principle: High-pressure jets of cleaning fluid remove surface contaminants.
• Advantages: Effective for cleaning flat surfaces and quick operation.
• Disadvantages: Ineffective for cleaning internal gaps; water pressure might damage materials.

2. Manual Cleaning

• Principle: Cleaning by hand with brushes and detergents.
• Advantages: Low cost and minimal equipment requirements.
• Disadvantages: Low efficiency, difficult to achieve high cleanliness, and may cause material scratches.

3. Chemical Soaking

• Principle: Immersing material boxes in chemical solutions to dissolve contaminants.
• Advantages: Effective for removing stubborn chemical residues.
• Disadvantages: Time-consuming; chemicals may corrode the box surface and are not environmentally friendly.

4. Laser Cleaning

• Principle: High-energy laser beams vaporize contaminants.
• Advantages: No chemicals required, environmentally friendly.
• Disadvantages: High equipment cost, unsuitable for cleaning large batches of material boxes.

How to Choose the Right Ultrasonic Cleaning Equipment for Material Boxes?

1. Equipment Size

   Select an ultrasonic cleaning machine with a tank capacity that accommodates the material box size, ensuring complete immersion in the cleaning solution.

2. Ultrasonic Frequency

   High-frequency ultrasonic equipment (40kHz or above) is recommended for precision cleaning to avoid damage from excessive cavitation strength.

3. Cleaning Solution Selection

   Use neutral or mild alkaline cleaning solutions that effectively remove contaminants without corroding the material box surface.

4. Temperature Control

   Set the cleaning temperature between 30-40°C to improve cleaning efficiency while protecting materials from high-temperature damage.