Electrostatic Chuck Gap Structure for Faster Wafer Detachment
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Solution Overview
Problem
Existing electrostatic chucks face challenges in efficiently removing residual charges from the base body, leading to difficulties in detaching wafers and compromising productivity due to the accumulation of charge in the ceramic material with high dielectric constant, while maintaining mechanical strength and clamping force.
Innovation Solution
Incorporating a gap between the electrode and the base body, either as a vacuum or filled with gas, which reduces charge accumulation by providing a path for charge removal and maintaining contact between the electrode and the base body for clamping force, thereby improving detachment efficiency and mechanical strength.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If the base body is made of ceramic material with high dielectric constant to maintain mechanical strength, then the mechanical strength is improved, but residual charge accumulates in the base body making wafer detachment difficult
Solution Approach 1:
The patent extracts the charge accumulation problem from the base body by introducing a gap structure that provides a dedicated charge removal path. The gap is formed between the electrode and base body, creating a region where residual charges can be discharged without affecting the mechanical strength of the ceramic base body.
Solution Approach 2:
The gap structure acts as an intermediary between the electrode and base body, facilitating charge removal while maintaining the mechanical integrity of the base body. The gap provides a medium through which charges can be discharged, mediating between the conflicting requirements of mechanical strength and charge removal efficiency.
2Force
If voltage is supplied to the electrode to clamp the wafer, then the clamping force is improved, but residual charge accumulates in the base body
Solution Approach 1:
The patent extracts the charge accumulation issue from the clamping function by providing a separate gap structure dedicated to charge removal. This allows the electrode to maintain clamping force through voltage supply while the gap simultaneously provides a path for residual charge to be discharged, separating the clamping function from charge accumulation.
Solution Approach 2:
The gap structure serves as an intermediary that enables the electrode to perform clamping without causing charge accumulation problems. It mediates between the electrical function (clamping through voltage) and the charge management requirement, allowing both to coexist.
3Strength
If the electrode is in full contact with the base body to maintain mechanical strength, then the mechanical strength is improved, but charge removal becomes difficult
Solution Approach 1:
The patent extracts a portion of the contact interface between electrode and base body to create the gap structure. This localized extraction maintains overall mechanical strength while creating a dedicated region for charge removal, avoiding the need for complex charge removal mechanisms.
Solution Approach 2:
The gap structure introduces local quality variation in the electrode-base body interface. Instead of uniform contact, the gap is formed at specific locations to provide charge removal paths while maintaining contact in other areas to preserve mechanical strength, achieving different functions in different regions.
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 gap between the electrode and the base body facilitates faster removal of residual charges, enhances wafer detachment, and maintains mechanical strength and clamping force, improving overall productivity and reducing the likelihood of dielectric breakdown.
Implementation Method 1
A gap which is rendered a vacuum or is filled with a gas is interposed between a side surface of the electrode and the base body
Implementation Method 2
by supplying voltage to the electrode, the base body is charged and the wafer is clamped
Implementation Method 3
the base body is charged and the wafer is clamped
Data Source
AI summary
An electrostatic chuck includes an insulating base body including a predetermined surface, and an electrode inside the base body, which is layer shaped along the predetermined surface. An upper surface of the electrode facing a side where the predetermined surface is located and the base body are in contact. A gap which is rendered a vacuum or filled with a gas is interposed between a side surface of the electrode and the base body.