Automated Electrostatic Bonding for Thin Wafer Handling
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Solution Overview
Problem
The handling of thin, mismatched, and ultrathin semiconductive wafers in the semiconductor and display industry poses challenges due to their fragile nature and varying shapes, requiring an automated solution for precise mating and separation with mobile electrostatic carriers to ensure safe handling and efficient processing.
Innovation Solution
An automated electrostatic bonding/de-bonding apparatus utilizing a pick-and-place robot arm and a bonding/de-bonding station to precision place and separate semiconductive wafers from mobile electrostatic carriers, incorporating a transfer enclosure, I/O ports, and a control unit to manage the process, ensuring secure electrostatic bonding and de-bonding while preventing external interference.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If manual handling methods are used for thin semiconductive wafers, then flexibility in handling is maintained, but handling safety and precision deteriorate due to the fragile nature and varying shapes of the wafers
Solution Approach 1:
A mobile electrostatic carrier (MESC) is introduced as an intermediary device between the thin wafer and the handling system. The MESC provides a rigid support structure that enables safe mechanical handling while the wafer itself remains thin and fragile. The carrier acts as a mediator that transfers the wafer between processing stations without requiring direct handling of the fragile substrate.
Solution Approach 2:
The patent replaces manual mechanical handling with an automated pick-and-place robot arm that uses electrostatic bonding to attach and detach wafers from the MESC. This substitution eliminates the need for direct mechanical contact with the fragile wafer surface, preventing damage while maintaining precise control over the handling process.
2Manufacturing precision
If automated pick-and-place robot arm is used, then handling precision and safety are improved, but device complexity increases
Solution Approach 1:
The mobile electrostatic carrier (MESC) serves multiple functions: it provides mechanical support for the thin wafer, enables electrostatic bonding for precise placement, facilitates transport between processing stations, and allows for easy de-bonding. This multi-functionality reduces the need for multiple specialized devices, thereby managing system complexity while achieving high precision.
Solution Approach 2:
The system uses controllable electrostatic parameters (voltage, charge distribution) to achieve precise bonding and de-bonding of the wafer to the carrier. By changing the electrostatic field parameters, the robot arm can precisely control the attachment and release of the wafer without mechanical contact, achieving high placement precision.
3Strength
If electrostatic bonding is used to attach wafer to carrier, then bonding strength is improved, but de-bonding difficulty increases
Solution Approach 1:
The electrostatic bonding process uses periodic or cyclic control of the electrostatic field. The robot arm applies voltage to create strong bonding during transport and processing, then periodically reverses or removes the voltage to enable easy de-bonding. This periodic application and removal of the electrostatic field allows strong bonding when needed and easy separation when required.
Solution Approach 2:
The electrostatic bonding system is dynamic and controllable, allowing the bonding strength to be adjusted in real-time. The robot arm can modify the voltage levels and charge distribution on the MESC to achieve optimal bonding strength for transport, then dynamically reduce or reverse the charge to facilitate easy de-bonding at the destination, making the process adaptable to different operational requirements.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The apparatus efficiently automates the mating and separation process, providing precise handling and rigidity to thin substrates, enabling their safe processing and integration into high-tech systems, while ensuring secure electrostatic bonding and de-bonding, thus addressing the challenges of handling fragile and varied wafer shapes.
Implementation Method 1
substrate to mobile electrostatic carrier (MESC) bonding is used in fabrication of semiconductor devices
Implementation Method 2
MESC technology can generate very large bonding forces to hold the target wafer
Data Source
AI summary
An automated electrostatic bonding/de-bonding apparatus is used to automate a mating or separating process between a semiconductive wafer and a mobile electrostatic carrier (MESC). The apparatus includes a transfer enclosure, a robot arm, a bonding/de-bonding station, input/output (I/O) ports, I/O cassettes, and a control unit. The I/O cassettes house the different dispensable items that are used during the mating or separating process, such as semiconductive wafers, MESCs, and mated assemblies thereof. The robot arm moves the dispensable items between the I/O cassettes and the bonding/de-bonding station. The transfer enclosure prevents any external physical interference with the movement of the robot arm. The I/O ports integrated into the transfer enclosure allow the robot arm to access the I/O cassettes, which are located outside of the transfer enclosure. The control unit is used to manage the functionalities of the robot arm and the bonding/de-bonding station.