Ringed Wafer Mounting Chuck for Solder Bump Formation
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Solution Overview
Problem
Large, thin semiconductor wafers are prone to warping, chipping, or breaking due to thermal and mechanical stresses, which complicates the formation of desired device structures and solder bumps, especially when using conventional techniques that require backside grinding tape, limiting efficient and reliable top-side processing.
Innovation Solution
A mounting chuck with a raised portion and recessed ring is used to securely hold a ringed wafer, allowing for stable and efficient formation of solder bumps on the front side without the limitations of backside grinding tape, enabling top-side processing and preventing damage from thermal, chemical, or mechanical stresses.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If large, thin wafers are used to increase device density and utilization, then productivity and area utilization are improved, but the wafers become susceptible to warping, chipping, and breaking due to thermal and mechanical stresses
Solution Approach 1:
The wafer is segmented into a central thinned region and a peripheral ring structure with different thicknesses. The peripheral ring maintains greater thickness to provide mechanical strength and resistance to warping, while the central region is thinned to enable device formation and dual-side processing. This segmentation allows the wafer to simultaneously achieve high device density and structural reliability.
2Stability of the object's composition
If conventional backside grinding tape techniques are used to prevent warping, then wafer stability is improved, but top-side processing efficiency and reliability are limited
Solution Approach 1:
Instead of applying support tape to the backside of the wafer as in conventional techniques, the invention inverts the approach by creating an integrated ring structure on the wafer's periphery that provides mechanical support. This allows top-side processing to proceed without the limitations imposed by backside tape, improving both stability and manufacturing ease.
Solution Approach 2:
The peripheral ring structure acts as an intermediary element that provides mechanical support and warping prevention without interfering with top-side processing operations. This ring structure mediates between the need for wafer stability and the need for efficient top-side manufacturing, enabling both objectives to be achieved simultaneously.
3Adaptability or versatility
If thin substrates are used to enable dual-side processing and compact devices, then device compactness and processing versatility are improved, but the substrates become more prone to mechanical damage
Solution Approach 1:
The wafer exhibits local quality variations with different thicknesses in different regions. The central region is thinned to enable dual-side processing and compact device formation, while the peripheral ring maintains greater thickness to provide mechanical strength and damage resistance. This local differentiation allows the substrate to simultaneously achieve versatility and strength.
Data Source
AI summary
At least one circuit element may be formed on a front side of a ringed substrate, and the ringed substrate may be mounted on a mounting chuck. The mounting chuck may have an inner raised portion configured to receive the thinned portion of the substrate thereon, and a recessed ring around a perimeter of the mounting chuck configured to receive the outer ring of the ringed substrate therein. At least one solder bump may be formed that is electrically connected to the at least one circuit element, while the ringed wafer is disposed on the mounting chuck.