Chuck Table Frame Cooling for Wafer Thickness Uniformity
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional wafer grinding apparatuses experience minute thickness variations of approximately 2 μm to 3 μm due to deformation of the chuck table frame during the grinding process, leading to quality issues with thin wafers.
Innovation Solution
The processing apparatus incorporates a chuck table with a porous plate and a frame assembly that includes cooling water channels and independent suction holes to maintain the frame's shape and temperature, ensuring the holding surface conforms to the wafer's shape, thereby minimizing thickness variations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If the chuck table frame is used without cooling, then the structure is simple, but the frame deforms during grinding causing thickness variations
Solution Approach 1:
The patent introduces cooling water channels to change the thermal parameter of the frame assembly, maintaining it at a predetermined temperature to prevent thermal deformation during grinding, thereby improving wafer thickness uniformity
Solution Approach 2:
The frame assembly is segmented to include multiple cooling water channels distributed throughout its structure, allowing targeted cooling of different regions to prevent localized deformation that would affect holding surface flatness
2Manufacturing precision
If the holding surface is shaped to match the wafer, then the wafer thickness can be uniformized, but minute thickness variations of 2-3 μm still occur due to frame deformation
Solution Approach 1:
The patent maintains the holding surface shape stability by controlling the temperature parameter of the frame assembly through cooling water channels, preventing thermal expansion and contraction that would cause the holding surface to deform during the grinding process
Solution Approach 2:
The cooling water channels are pre-installed in the frame assembly to provide beforehand cushioning against thermal deformation, ensuring the holding surface maintains its shaped geometry throughout the grinding process without minute thickness variations
3Manufacturing precision
If cooling water channels are added to the frame assembly, then frame deformation is prevented, but the device complexity increases
Solution Approach 1:
The cooling water channels are merged into the frame assembly structure itself, combining the structural support function with the thermal management function in a single integrated component, thereby minimizing the increase in device complexity
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 reliably fixes the frame assembly to the table base and maintains a predetermined temperature, ensuring the holding surface and ground surface shapes align, effectively reducing wafer thickness variations and preventing processing fluid and ground-off chips from causing further thickness issues.
Implementation Method 1
a porous plate having an attracting surface for attracting the wafer thereto
Implementation Method 2
a frame suction hole that is defined in the rest surface and transmits a suction force therethrough to attract the frame assembly to the rest surface
Implementation Method 3
a cooling water channel that is defined in the frame assembly and guides cooling water to an entire inner area of the frame assembly
Implementation Method 4
a wafer suction hole that is defined in the frame assembly and transmits a suction force to the attracting surface of the porous plate
Data Source
AI summary
A holding unit of a processing apparatus includes a chuck table for holding the wafer thereon and a table base on which the chuck table is detachably supported. The chuck table includes a porous plate having an attracting surface for attracting the wafer thereto, a frame assembly surrounding a portion of the porous plate other than the attracting surface, a cooling water channel that is defined in the frame assembly and guides cooling water to an entire inner area of the frame assembly, a wafer suction hole that is defined in the frame assembly and transmits a suction force to the attracting surface of the porous plate, and a bolt hole defined in the frame assembly to fasten the chuck table to the table base.