Grinding Apparatus Support Pole Air Cooling
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Solution Overview
Problem
In grinding apparatuses, thermal expansion of support poles and tables due to processing heat can cause inclination changes in the holding table, especially when grinding hard wafers like sapphire or silicon carbide, leading to deformation and poor grinding quality.
Innovation Solution
The grinding apparatus incorporates through-holes in support poles connected to an air supply and exhaust system, which cools the support poles and tables to prevent thermal deformation, using air to be supplied into the through-holes and exhausted towards the support table to maintain stability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If grinding water is supplied to the upper face of the wafer to remove processing heat, then the wafer can be cooled, but processing heat is transmitted to the substrate and support pole through the holding table, causing thermal expansion and inclination change
Solution Approach 1:
The patent introduces air as an intermediary cooling medium that flows through the holding table via through-holes. This air cooling system acts as a mediator between the heat source (wafer) and the support structure, removing heat from the holding table and support poles without requiring direct contact with grinding water, thereby preventing thermal expansion while maintaining wafer cooling effectiveness
Solution Approach 2:
The patent employs a pneumatic cooling system where compressed air is supplied through nozzles and flows through through-holes in the holding table and support poles. This pneumatic approach replaces liquid cooling (grinding water) for the support structures, using gas flow to remove heat and prevent thermal deformation while avoiding the harmful effects of water contact with electrical components
2Reliability
If a substrate made of ceramics is pasted to the wafer to hold it on the holding table for hard board grinding, then the wafer can be securely held, but the substrate transmits heat to the support pole through the holding table, causing thermal expansion
Solution Approach 1:
The patent extracts the heat transmission path from the support pole by introducing through-holes that allow cool air to flow through the holding table and support poles. This removes the thermal coupling between the hot wafer/substrate assembly and the support structure, preventing heat accumulation and thermal expansion while maintaining secure wafer holding through the ceramic substrate
3Productivity
If the holding table is rotated and grindstones are contacted with the wafer during rotation for grinding, then the wafer can be ground, but processing heat is generated and transmitted to the holding table and support pole, causing thermal deformation
Solution Approach 1:
The patent implements preliminary cooling action by supplying cool air through nozzles and through-holes before and during the grinding process. This pre-cooling of the holding table and support poles prevents heat accumulation from the grinding process, maintaining structural stability and preventing thermal deformation while allowing continuous high-efficiency grinding operation
Solution Approach 2:
The patent ensures continuous cooling action during the entire grinding process by maintaining air flow through the holding table and support poles throughout the rotation and grinding cycle. This continuous removal of processing heat prevents thermal accumulation and maintains the geometric stability of the holding table, enabling sustained high-productivity grinding without thermal deformation
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 cooling mechanism effectively suppresses thermal expansion of support poles and tables, preventing inclination changes in the holding table, ensuring stable wafer grinding.
Implementation Method 1
air being supplied into the through-hole to cool each of the support poles while the air having flowed through the through-hole is exhausted toward the support table to cool the support table
Implementation Method 2
the holding table receiving the heat is sometimes deformed by thermal expansion thereof
Data Source
AI summary
A grinding apparatus includes a holding table for holding a wafer, a support table for supporting the holding table, a motor for rotating the support table, a frame member supporting the support table for rotation, and at least three support poles for supporting the frame member from the base. Each of the support poles has formed in the inside thereof a through-hole, a supply port which communicates the through-hole and an air supply source with each other, and an exhaust port which exhausts air having flowed through the through-hole toward the support table. Air is supplied into the through-hole to cool the support pole, and the air having flowed through the through-hole is exhausted toward the support table.