Ceramic Electrostatic Chuck Terminal Hole Tapering Against Cracks
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Solution Overview
Problem
The existing semiconductor manufacturing apparatus members, such as ceramic heaters and electrostatic chucks, are prone to damage, particularly cracking and delamination, due to thin portions caused by thermal stress and processing loads at the intersection of the electrode lead-out portion and terminal hole in the ceramic plate.
Innovation Solution
A ceramic plate design with a terminal hole that tapers toward its bottom, intersecting the electrode lead-out portion, which increases the thickness of the ceramic plate at this junction, reducing the likelihood of damage by distributing stress more evenly.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If the terminal hole has a flat bottom surface intersecting the slanting lateral surface of the electrode lead-out portion, then the structure is simple to manufacture, but the ceramic plate develops thin portions that are prone to cracking and delamination under thermal stress and processing loads
Solution Approach 1:
The patent changes the geometric parameters of the terminal hole from a flat bottom surface to a tapered bottom surface with a specific angle (5°-30° relative to the horizontal plane). This parameter change eliminates the thin portion problem by ensuring the hole bottom does not intersect the electrode lead-out portion's lateral surface, thereby preventing cracking and delamination while maintaining manufacturability through standard machining processes
Solution Approach 2:
The patent applies local quality by creating a specific tapered geometry only at the bottom of the terminal hole where it intersects with the electrode lead-out portion. This localized geometric modification ensures adequate ceramic thickness precisely at the stress-prone intersection area without affecting other parts of the structure, thus improving reliability where needed most
2Reliability
If the electrode lead-out portion has a truncated conical shape with a slant angle of 40° or less, then the bonding area is sufficient for electrical connection, but the ceramic plate develops thin portions between the lead-out portion and terminal hole that are prone to damage
Solution Approach 1:
The patent modifies the terminal hole geometry by introducing a tapered bottom surface with a controlled angle (5°-30°), which changes the spatial relationship between the hole and the electrode lead-out portion. This ensures that even with a truncated conical lead-out portion, the ceramic plate maintains adequate thickness throughout, preventing structural weakness while preserving the electrical connection function
3Adaptability or versatility
If the ceramic plate thickness is reduced at the terminal hole intersection to accommodate the electrode lead-out portion, then the assembly fits better, but the ceramic plate becomes more susceptible to cracking and delamination under thermal stress and processing loads
Solution Approach 1:
Instead of reducing the ceramic plate thickness to accommodate the electrode lead-out portion, the patent inverts the approach by designing the terminal hole with a tapered bottom that prevents intersection with the lead-out portion's lateral surface. This inversion of the conventional design approach ensures the ceramic maintains its full thickness, thereby preventing damage while still achieving proper assembly fit through the tapered hole geometry
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 design minimizes cracking and delamination by maintaining a thicker ceramic plate structure, ensuring improved durability and conductivity through optimized contact areas and reduced thermal expansion differences.
Implementation Method 1
the terminal hole tapering surface intersects the lateral surface of the electrode lead-out portion. This allows the portion of the ceramic plate between the electrode lead-out portion and the terminal hole to be thicker by the amount corresponding to the amount of slant of the terminal hole tapering surface than a portion between a flat bottom surface of the terminal hole and the slanting lateral surface of the electrode lead-out portion intersecting each other. Thus, the ceramic plate is less likely to have a thin portion, reducing damage in the member for semiconductor manufacturing apparatus.
Implementation Method 2
a conductive bonding portion located between the terminal and the electrode lead-out portion and bonding the terminal and the electrode lead-out portion together
Data Source
AI summary
A member for semiconductor manufacturing apparatus includes a ceramic plate having a wafer placement surface on an upper surface, an electrostatic electrode embedded in the ceramic plate, an electrode lead-out portion embedded in the ceramic plate and extending downward from the electrostatic electrode, a terminal hole extending from a lower surface of the ceramic plate to the electrode lead-out portion, a terminal in the terminal hole, a conductive bonding portion located between the terminal and the electrode lead-out portion and bonding the terminal and the electrode lead-out portion together. The terminal hole has a terminal hole tapering surface that tapers toward a bottom of the hole, and the terminal hole tapering surface intersects a lateral surface of the electrode lead-out portion.