Wafer stage and method of manufacturing the same
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Solution Overview
Problem
In semiconductor manufacturing processes, the temperature dependency of processes such as etching increases due to fine pitches and aspect ratios, reducing the margin of temperature control, and requiring careful temperature management to prevent warpage and delamination of electrostatic chuck plates.
Innovation Solution
A wafer stage design incorporating an electrostatic chuck plate made of ceramics, an upper supporting plate with a composite material of aluminum or aluminum alloy and ceramics, and a Peltier element for temperature control, directly bonded using a room temperature solid bonding process, along with a flexible thermal conductive sheet to minimize heat capacity and withstand pressure differences between vacuum and atmospheric pressures.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If the electrostatic chuck plate is made of ceramics to prevent warpage and delamination, then temperature control stability is improved, but the heat capacity increases which slows down temperature response
Solution Approach 1:
The electrostatic chuck plate is divided into two separate components: a ceramic plate (providing stability and warpage prevention) and a metal plate (providing low heat capacity and fast temperature response). These segments are bonded together to form a composite structure that combines the advantages of both materials.
Solution Approach 2:
A composite structure consisting of a ceramic plate and a metal plate is used. The ceramic plate provides dimensional stability and prevents warpage, while the metal plate provides low heat capacity for fast temperature response. This composite material approach resolves the contradiction between stability and response time.
2Strength
If the upper supporting plate is made of a composite material of aluminum and ceramics to withstand pressure difference, then structural strength is improved, but manufacturing complexity increases
Solution Approach 1:
The upper supporting plate is segmented into a metal plate (aluminum or aluminum alloy) and a ceramic plate that are separately manufactured and then bonded together. This allows each component to be optimized for its specific function while simplifying the manufacturing process compared to creating a monolithic composite.
Solution Approach 2:
A bonding process is used as an intermediary step to join the metal plate and ceramic plate. This bonding interface acts as a mediator that transfers mechanical loads between the two materials, enabling the composite structure to withstand pressure differences while maintaining manufacturing simplicity.
3Device complexity
If the ESC plate and upper supporting plate are directly bonded by room temperature solid bonding, then the number of manufacturing steps is reduced, but bonding reliability may decrease
Solution Approach 1:
The bonding process is performed at room temperature rather than high temperature, which simplifies the manufacturing process. Surface treatments or intermediate layers may be applied to enhance bonding reliability at room temperature, compensating for the lower energy input compared to high-temperature bonding.
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 solution provides improved temperature control and prevents warpage of the electrostatic chuck plate, ensuring sufficient strength to endure pressure differences and maintaining accurate temperature management during semiconductor fabrication processes.
Implementation Method 1
a Peltier element for temperature control
Implementation Method 2
directly bonded using a room temperature solid bonding process
Data Source
AI summary
A wafer stage includes an electrostatic chuck (ESC) plate, an upper supporting plate, a lower supporting plate and a temperature controller. The ESC plate includes a first surface that supports a wafer. The upper supporting plate is bonded to a second surface of the ESC plate opposite to the first surface. The lower supporting plate overlaps the upper supporting plate. The temperature controller is disposed between the upper supporting plate and the lower supporting plate. The ESC plate includes ceramics. The upper supporting plate includes a composite material of aluminum or aluminum alloy and ceramics or carbon. The ESC plate and the upper supporting plate are directly bonded to each other by a room temperature solid bonding process. Thus, the wafer stage has sufficient strength to withstand pressure differences between a vacuum and atmospheric pressure, improved temperature response by minimizing heat capacity, and prevents warpage of the ESC plate.