1. Introduction

In the semiconductor manufacturing process, the precise handling, calibration and alignment of wafers are key links to ensure the yield of chips. Wafer transfer systems, wafer calibrators, wafer loading systems, ceramic chip forks and wafer alignment stations are core components in semiconductor equipment. They work together to ensure that wafers maintain high-precision positioning during processes such as photolithography, etching and cleaning. This article will introduce in detail the working principles, structural features and application scenarios of these devices.

2. Wafer Transfer System

2.1 Working Principle

The wafer transfer system is responsible for efficiently and stably moving wafers between semiconductor manufacturing equipment such as photolithography machines, etching machines, and cleaning machines. Its core functions include:

Vacuum adsorption/mechanical clamping: Use vacuum suction cups or mechanical grippers to fix the wafers to prevent slippage or damage.

High-precision motion control: Driven by linear motors or servo motors, it ensures the precise positioning of wafers on the X, Y, and Z axes.

Anti-shock and anti-static design: To prevent the generation of static electricity or vibration during handling, which may affect the wafer yield.

2.2 Structural Characteristics

Multi-axis robotic arm: High-rigidity materials (such as aluminum alloy or carbon fiber) are adopted to reduce vibration.

Vacuum/mechanical clamping mechanism: Suitable for wafers of different sizes (such as 6 inches, 8 inches, 12 inches).

Sensor feedback: Equipped with optical or capacitive sensors to ensure precise wafer position.

2.3 Application Scenarios

Wafer transfer between photolithography machines and etching machines

The transportation between wafer cleaning equipment and coating equipment

Wafer scheduling in automated production lines (AMHS)

3. Wafer Aligner

3.1 Working Principle

The wafer calibrator is used to precisely align the wafer before the process, ensuring that the chip pattern perfectly matches the Mask or Reticle. Its core functions include:

Edge Alignment: Detect the edge of the wafer through optical or mechanical means and adjust the position.

Mark Alignment: Precise positioning is achieved by using the Alignment Mark on the wafer.

Rotation Compensation: Correcting minor rotation deviations of wafers caused by handling or process.

3.2 Structural Characteristics

High-resolution optical system: CCD or laser sensor is used to detect alignment marks.

Fine-tuning mechanism: Precise adjustment of the XYZ three-axis to ensure sub-micron alignment accuracy.

Anti-vibration platform: Reduces the impact of environmental vibration on alignment accuracy.

3.3 Application Scenarios

Wafer alignment before the lithography process

Position calibration before Die Bonding of chips

Multi-layer alignment in advanced packaging (such as TSV, 3D IC)

4. Wafer Loading System

4.1 Working Principle

The wafer loading system is responsible for removing the wafers from the FOUP (Front Open Wafer Transfer Box) or wafer Cassette and feeding them into the process equipment. Its core functions include:

Wafer grasping and releasing: Vacuum suction cups or mechanical grippers are used to ensure stable wafer grasping.

FOUP/Cassette docking: Compatible with standard wafer casings, enabling automated loading.

Anti-pollution design: Use cleanroom-grade materials (such as stainless steel or PEEK) to reduce particle contamination.

4.2 Structural Characteristics

Multi-stage vacuum adsorption: Adaptable to wafers of different sizes, preventing slippage.

FOUP/Cassette automatic identification: Identify the wafer box type through sensors to optimize the loading process.

Cleanroom compatibility: Compliant with SEMI standards, suitable for clean environments ranging from Class 1 to 100.

4.3 Application Scenarios

Automatic wafer loading of equipment such as photolithography machines, etching machines, and ion implanters

Wafer scheduling system in semiconductor production lines

5. Ceramic Wafer Fork

5.1 Working Principle

Ceramic fork is a special tool used for wafer handling, mainly for the handling of wafers in high-temperature processes (such as oxidation and diffusion) or special materials (such as sapphire and SiC). Its core functions include:

High-temperature resistance: Ceramic materials (such as Al₂O₃ or Si₃N₄) can withstand temperatures above 1000℃.

Anti-static design: Reduce the damage of static electricity to wafers.

Low coefficient of thermal expansion: Avoids deformation at high temperatures and ensures the stability of the wafer.

5.2 Structural Characteristics

High-purity ceramic materials: corrosion-resistant and heat-resistant, suitable for special process environments.

Precision processing: Smooth surface, reducing the risk of wafer scratches.

Anti-static coating: Suitable for sensitive chips (such as MEMS, power devices).

5.3 Application Scenarios

Wafer handling in high-temperature oxidation furnaces and diffusion furnaces

Processing of special material wafers such as sapphire and SiC

6. Wafer Alignment Stage

6.1 Working Principle

Wafer alignment stations are used to adjust the position of wafers with micron-level or even nanometer-level precision during the process, ensuring the accuracy of processes such as photolithography and coating. Its core functions include:

XYZ three-axis precision motion: Driven by linear motors or piezoelectric ceramics, sub-micron positioning is achieved.

Rotational alignment (θ axis adjustment) : Corrects minor rotational deviations of the wafer.

Vacuum adsorption fixation: Prevents wafers from moving during the process.

6.2 Structural Characteristics

High rigidity structure: Reduces the impact of vibration on alignment accuracy.

Precision guide rails and lead screws: Ensure smooth movement and reduce backlash errors.

Temperature compensation system: Reduces the impact of thermal expansion on alignment accuracy.

6.3 Application Scenarios

Precise positioning of wafers in lithography machines and coating machines

Multi-layer alignment in advanced packaging (such as hybrid bonding)

7. Summary

Wafer transfer systems, wafer calibrators, wafer loading systems, ceramic chip forks and wafer alignment stations are key equipment in semiconductor manufacturing. Together, they ensure the high-precision handling, calibration and alignment of wafers during the process. As semiconductor technology moves towards smaller processes (such as 3nm and 2nm), these devices will evolve towards higher precision and greater intelligence, providing more reliable guarantees for chip manufacturing.

Future development trend

Intelligence and automation: Combined with AI visual inspection, improve alignment accuracy and efficiency.

New material application: such as silicon carbide (SiC) ceramic plate forks, suitable for higher-temperature processes.

Modular design: Facilitates equipment maintenance and upgrade, and ADAPTS to different process requirements.

The continuous optimization of these devices will drive semiconductor manufacturing towards higher efficiency and lower costs.