Engineering Notes by Oriental Motor

Simplify Semiconductor Wafer Handling with Modular Products from the Same Family

[fa icon="calendar"] Oct 31, 2023 6:45:48 PM / by Johann Tang

Johann Tang

Semiconductor wafers are the foundation of semiconductor chip manufacturing. The growing demand for semiconductors, driven by technological advancements like AI, IoT, and robotics, makes it crucial to handle these delicate wafers efficiently and precisely. In this article, we will explain how unified features from a family of modular motors and linear actuators can simplify and optimize process automation, such as semiconductor wafer handling.

What is a wafer?

A wafer is a thin, flat, and typically circular slice or substrate of a crystalline semiconductor material.  These wafers are typically made from silicon, although other materials like gallium arsenide are also used in certain applications.  Wafers serve as the foundation for manufacturing integrated circuits (ICs) and other electronic components.

These wafers need to be handled delicately and precisely to prevent damage.  Typically, wafers are handled and transported inside a wafer processor.

Wafers (Wikipedia)

 

How can the AlphaStep AZ Series product family simplify wafer transfer?

Motors, linear actuators, and rotary actuators from Oriental Motor's AlphaStep AZ Series product family offer universal features, drivers, and software.  All motor systems are equipped with a battery-free absolute encoder, low-loss lamination technology, and reliable Keep-in-Step technology with automatic correction.  The driver's servo-emulation mode enables high efficiency, low-noise operation where the motor uses just the right amount of current for the motion profile.

These products are modular; meaning different types of motors, actuators, and drivers can be mixed and matched according to your needs.

The simplified setup not only reduces the material costs, wiring time, and problems related to sensors but also enhances functionality without sacrificing performance.

We will go over three motion axes typically used in a wafer handling process: the loading/loading axis, the transfer process, and the alignment process.

 

Blog - loader, transfer, and machining system AZ family lineup

 

Jump to section:
Loading/Unloading
Wafer Transfer
Wafer Alignment

 

Loading/Unloading

Semiconductor wafers need to be lifted and lowered from time to time, such as in a loading/unloading axis.  By using the L Series that combines an integrated closed-loop stepper motor with a rack-and-pinion mechanism, a high precision and high load vertical drive can be performed with ease.

  • Compact and high strength 
    The rack and pinion design can easily convert rotary motion into linear motion.  Although the linear motion mechanism is compact, it can still lift or lower a heavy load up to 100 kg (up to 200 kg with newer LJ Series) due to its high strength design.
Blog - operation of a rack and pinion system

Operation of a rack-and-pinion system

The gear (deceleration unit) is driven by the pinion shaft of the motor, and further transmits it from the pinion gear then to the rack to convert it into linear motion.

  • Quicker design and assembly
    Since the rack-and-pinion system is pre-assembled, it reduces the time needed to design (including material selection, mechanism design, and management of blueprints) and assembly.  Both ends of the rack can also be fixed in place to allow the motor to run by itself. 
Save space with preassembled rack and pinion system

Components used

① Fixed-side block ② Transportation table ③ Linear guide ④ Support-side block ⑤ Coupling case ⑥ Coupling ⑦ Fixed-side bearing ⑧ Ball screw ⑨ Support-side bearing

Due to the built-in battery-free encoder, external sensors can also be eliminated.

  • High positioning accuracy 
    A high level of repetitive positioning accuracy can be achieved, which enables precse lifting and lowering of the load.

    Vertical operation is also simple. A model equipped with an electromagnetic brake is also available as a fall prevention measure.
Vertical operation with rack and pinion lift
Repetitive positioning accuracy (reference value)

This is the actual measurement value with a transportable mass. It will vary depending on the load, driving conditions, and mounting direction.

Product Name Rack Moving Method Repetitive Positioning Accuracy [mm]
LM2 Parallel ±0.25
LM4
LM2 Perpendicular ±0.07
LM4
  • Easy unit setting
    By using the universal MEXE02 support software, the travel amount can be set easily in millimeter units instead of steps or degrees.
MEXE02 motion software - unit setting
Minimum step angle
High-Speed Type: 0.01 mm
Large Transportable Mass Type: 0.001 mm
Operating speed range
0~500 mm/s (High-speed type)
0~90 mm/s (60 mm frame size for large transportable mass type)
0~40 mm/s (80 mm frame size for large transportable mass type)

 

L Series Rack and Pinion Systems
L Series rack and pinion systems

 

Wafer Transfer

Wafer transfer stations present unique challenges, including high inertia handling and the need for precise operations.  The closed-loop AZ series stepper motors with harmonic gearhead offer tailored solutions to meet these demanding requirements.

  • Homing without external sensors 
    The αSTEP AZ Series is equipped with a battery-free mechanical absolute encoder at the rear of the motor, which enables high speed sensorless homing operation.  It will also protect against the effects of any external sensor malfunctions.
  • High accuracy/non-backlash
    Unlike other gearheads, a harmonic gearhead provides backlash-free positioning accuracy.  The harmonic gear has many teeth in simultaneous meshing engagement, and it is designed to average out the effects of tooth pitch error and cumulative pitch error to ensure high positioning accuracy (0.025˚ to 0.017˚ depending on size).
Harmonic gear construction Harmonic gear angular transmission accuracy
  • Geared type for high inertia
    The AZ series includes various geared types and gear ratios designed to handle high inertia loads effectively. This ensures that wafers can be transported safely and precisely.
Small turning radius means less inertia Large turning radius means more inertia
  • Integration and downsizing 
    Oriental Motor’s geared motors do not require couplings as the teeth are cut directly on the motor's shaft, and therefore they are shorter in length.
Non-coupled gearheads saves space

 

 

AZ Series Stepper Motors (Harmonic Gear Type)
AZ Series stepper motor with harmonic gearhead

 

 

Wafer Alignment

Semiconductor wafer handling requires precision, high responsiveness, and synchronization between multiple motors and actuators. Oriental Motor's DR/DRS Series compact cylinders with the same closed-loop technology from the AlphaStep AZ series motors provide characteristics that can do exactly that.  With a hollow rotor and direct assembly design, rigidity is improved while backlash is reduced.

 

  • Precise and responsive
    These compact cylinders are highly responsive and reliable due to the built-in AlphaStep closed-loop technology, making them ideal for wafer handling tasks.  Notably, they are tuning-free, further simplifying setup.
Blog - DR cross section
Ball screw type:
ground or rolled
Minimum Step Angle:
0.001 mm

Repetitive Positioning Accuracy:
Ground Ball Screw: ±0.003 mm
Rolled Ball Screw: ±0.01 mm
  • Easily synchronize motion
    A multi-axis driver allows for easy synchronous motion, streamlining the control system and improving operational efficiency.

4-axis EtherCAT-compatible controller

Blog - multi-axis

Consolidate:

  • Main power supply cable
  • Control power supply cable
  • Communication cable
  • Motor cables
  • Compact design
    Because connecting parts such as linear guides and couplings are no longer necessary, the equipment as a whole can be made smaller. The number of required parts is also significantly smaller compared to self-made mechanisms.
Self-built  
Blog - self built ① Mounting plate ② Transportation table ③ Linear guide ④ Coupling ⑤ Fixed-side block ⑥ Ball screw ⑦ Fixed-side bearing ⑧ Support-side block ⑨ Support-side bearing
When using DR Series table type  
Blog - when using DR The DR Series is pre-assembled
with all necessary components
and offers space savings.
  • 4 mounting methods 
    With various mounting methods available, allowing for flexible mounting options to suit small spaces.  Through multiple combinations, an XYZ unit can be configured to create compact equipment.
Front mounting Side mounting Flange mounting Foot mounting
Blog - wafer handling - bracket mounting Blog - wafer handling - flange mounting Blog - wafer handling - screw mounting Blog - wafer handling - bottom mounting

 

DR/DRS Series Compact Cylinders
DR/DRS Series compact cylinders

 

Summary

In semiconductor wafer handling, precision and reliability are paramount, and Oriental Motor offers a diverse range of motor and linear actuator options to meet these stringent requirements.  Using products that share universal features and functions can simplify setup and programming while saving time and resources for something more important.

 

Unified control for a wide variety of applications

The αSTEP AZ Series product family offers a wide, modular product line of motors,  geared motors, linear/rotary actuators, grippers, and drivers.  By using universal drivers, software, and cables, the wiring and control are unified for a variety of motors and actuator options.

Benefits of Unification
  • Unified Wiring
  • Unified Control
  • Unified Maintenance
Because the I/O pin layout is the same, electrical design and wiring work can be performed efficiently. Since the control method is the same, different operations can be performed using the same method (including network control). Because they share the same motor, driver and cables, it is possible to reduce the inventory costs and storage space.

Unify motion control with products from the AlphaStep AZ Series family

 

The AZ Series product family also offers an industrial network compatible lineup that enables seamless integration into advanced control systems via EtherNetIP, EtherCAT, Profinet, or other communication protocols, providing the flexibility and efficiency required in the semiconductor industry.  We are constantly updating the technology and expanding the lineup, such as the new high power EtherNetIP and EtherCAT-compatible  AZX Series.

Oriental Motor - your go-to source for compact precision motion control

Oriental Motor's motors and linear actuators can be used to enhance precision, reduce complexity, and ensure efficient wafer handling in demanding environments. Whether you're working on cartesian XYZ systems, robotic arms/end-effectors, or AGVs and AMRs, Oriental Motor has a number of solutions to meet your specific needs.

For further technical information, sizing support, and to explore the wide range of motor solutions for semiconductor wafer handling, please contact our inside sales or technical support team to get started.

 

Topics: Stepper Motors, Robotics, Absolute Positioning, Alphastep Hybrid Control, Linear & Rotary Actuators, VIDEOS, Vertical Lifts, Application Examples

Johann Tang

Written by Johann Tang

Johann Tang is a Product Specialist at Oriental Motor USA Corp. with 20+ years of experience in sales, technical application support, and training of various types of fractional horsepower electric motors, gearheads, actuators, drivers, and controllers. Feel free to ask him questions on Linkedin.

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