Grinding Apparatus Cantilever Load Stability
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Solution Overview
Problem
Conventional grinding apparatuses are prone to tilting due to grinding load, leading to grinding failures, as the grinding means protrude and are supported in a cantilevered manner.
Innovation Solution
The grinding apparatus features a turntable with chuck tables disposed at equal angles, equipped with first and second grinding means having grinding wheels with abrasives, and guided by pairs of guides that allow for orthogonal alignment of grinding areas and reference lines, preventing the rotation center from tilting under grinding load.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If the grinding means protrude forward from the guides and are supported in a cantilevered manner, then the grinding apparatus can achieve simple structure and ease of manufacture, but the columns and the whole apparatus come to be readily tilted due to the grinding load generated by pressing of the upper surface of the wafer by the grinding abrasives
Solution Approach 1:
The support structure for the grinding means is segmented into two distinct parts: guides that provide lateral guidance and a support table that provides vertical support. This segmentation allows the grinding means to be supported at both the front and rear ends, eliminating the cantilevered configuration while maintaining manufacturing simplicity.
Solution Approach 2:
The support structure transitions from a one-dimensional cantilevered support (supporting only at the rear) to a two-dimensional support system where the grinding means are supported at both front and rear ends by the support table, which extends in the grinding feed direction. This dimensional change provides balanced support against grinding loads.
2Device complexity
If the grinding means are supported in a cantilevered manner, then the device complexity is reduced, but grinding failure occurs due to tilting of the rotation center position under grinding load
Solution Approach 1:
The support function is segmented between the guides (providing lateral constraint) and the support table (providing vertical support at both ends). This segmentation achieves reliable support against tilting without increasing overall device complexity, as the support table is a straightforward structural extension.
Solution Approach 2:
The support table acts as an intermediary structure between the grinding means and the column. It provides a stable platform that distributes the grinding load across multiple support points (front and rear ends), preventing direct transmission of tilting forces to the column and rotation center.
3Manufacturing precision
If the grinding means are positioned to protrude forward, then the grinding area can be optimized for wafer contact, but the grinding load causes tilting of the grinding means and rotation center
Solution Approach 1:
The positioning system is segmented into guides that define the precise lateral position of the grinding means and a support table that provides stable vertical support. This segmentation allows the grinding means to maintain optimized positioning for wafer contact while preventing tilting through balanced support at both ends.
Solution Approach 2:
The support table serves as an intermediary that decouples the grinding contact optimization from the stability issue. It provides a rigid platform that maintains the grinding means' position while distributing loads, allowing the grinding area to be optimized without compromising stability.
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 configuration effectively reduces the likelihood of grinding failure by evenly distributing the grinding load across the guides, maintaining the rotation center's stability and enhancing the accuracy of wafer thickness and surface finish.
Implementation Method 1
a pair of first guides that are parallel to the grinding feed direction and are disposed to sandwich the first grinding means and a first advancing-retreating shaft that causes the first grinding means whose direction is defined by the first guides to advance and retreat in the grinding feed direction
Data Source
AI summary
Grinding apparatus includes plural chuck tables disposed on a turntable, a first grinding unit and a second grinding unit that execute infeed grinding of a wafer, and a first grinding feed unit and a second grinding feed unit that execute grinding feed of them. Each grinding feed unit has a pair of guides parallel to the grinding feed direction and a ball screw. The grinding area of each grinding unit has a circular arc shape in which one end exists at the outer circumference of the wafer and the other end exists at the center of the wafer.