Electrostatic Chuck Plug Structure for Low-Cost Spark Prevention
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Solution Overview
Problem
The existing electrostatic chuck for semiconductor manufacturing requires a costly double firing process for the ceramic plate and porous plug, increasing manufacturing costs and potentially causing spark discharge near the wafer's back surface.
Innovation Solution
A ceramic plate with plug insertion holes and insulating plugs that allow gas passage, eliminating the need for firing the plug during assembly by using threaded connections for securement, ensuring the plug does not lift the wafer and preventing spark discharge with a flush upper surface design.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a porous plug is formed by firing ceramic mixture paste in a through-hole, then the plug prevents spark discharge near the wafer back surface, but the manufacturing cost increases due to requiring a second firing process
Solution Approach 1:
The patent replaces the expensive fired ceramic porous plug with a cheaper insulating material plug that does not require firing. The plug is made from inexpensive insulating materials such as resin or ceramic particles bound with binder, eliminating the need for a second high-temperature firing process while still providing the necessary electrical insulation to prevent spark discharge.
Solution Approach 2:
The patent changes the material state and formation method of the plug. Instead of using fired ceramic paste that requires high-temperature processing, the invention uses insulating materials that can be directly inserted and secured at room temperature or low temperature, fundamentally changing the manufacturing parameters and eliminating the second firing step.
2Reliability
If the plug upper surface is positioned lower than the wafer placement surface, then spark discharge is prevented, but the wafer support height is reduced
Solution Approach 1:
The patent applies local quality by positioning the plug upper surface lower than the wafer placement surface only in the specific region where the plug is located, while maintaining the normal wafer support height in other regions through the electrostatic chuck's electrode structure. This localized lowering prevents spark discharge at the plug location without compromising overall wafer support.
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
This solution reduces manufacturing costs by eliminating the need for a second firing step and minimizes spark discharge risks by maintaining a low profile and secure thread engagement, enhancing the reliability of the semiconductor manufacturing process.
Implementation Method 1
heat conduction between the wafer and the ceramic plate is improved
Implementation Method 2
the helium gas passes through pores of the porous plug
Implementation Method 3
an insulating plug that includes an external thread portion screwed on the internal thread portion
Implementation Method 4
a ceramic plate that has an upper surface including a wafer placement surface and that contains an electrode
Data Source
AI summary
A member for semiconductor manufacturing apparatus includes a ceramic plate that has an upper surface including a wafer placement surface and that contains an electrode; a plug insertion hole that is formed as at least a portion of a through-hole extending through the ceramic plate in an up-down direction, an internal thread portion being on an inner circumferential surface around the plug insertion hole; and an insulating plug that includes an external thread portion screwed on the internal thread portion on an outer circumferential surface and that allows gas to pass therethrough.