Stacked Semiconductor Assembly Thinning via Temporary Carrier Support
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Solution Overview
Problem
Conventional semiconductor stacking techniques face challenges in handling and thinning fragile thinned second dies, which are prone to breaking when thinned to final thicknesses less than 300 microns, limiting the reduction of semiconductor component footprint and height.
Innovation Solution
A method involving temporary carriers for structural support during thinning and stacking, where second dies are initially thicker for handling, then thinned to a uniform thickness after attachment, using underfill and encapsulant materials to secure and protect the dies during grinding, allowing for ultra-thin profiles and robust stacking.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If second dies are thinned to final thickness less than 300 microns before stacking, then the footprint and height of semiconductor component are reduced, but the dies become fragile and prone to breaking during handling
Solution Approach 1:
The patent applies preliminary action by thinning the second wafer to less than 300 microns thickness before singulation and stacking operations. This allows the thinned dies to be handled and stacked while still supported by the temporary carrier, preventing breakage that would occur if thinned individually. The temporary carrier provides mechanical support during the stacking process, enabling the footprint reduction goal to be achieved without sacrificing die integrity.
Solution Approach 2:
The temporary carrier serves as an intermediary that provides mechanical support to the thinned second wafer during handling and stacking operations. The carrier substrate with recesses holds the thinned dies in a supported manner, preventing them from breaking due to their reduced thickness. This intermediary structure enables the processing of ultra-thin dies that would otherwise be too fragile to handle.
2Productivity
If second wafer is thinned before singulation, then manufacturing efficiency is improved, but the thinned dies are difficult to handle and stack without breaking
Solution Approach 1:
The patent performs the thinning operation on the second wafer before singulation, which improves manufacturing efficiency by processing multiple dies simultaneously rather than individually. The temporary carrier maintains the mechanical strength of the thinned wafer during this preliminary thinning operation, enabling efficient batch processing while preventing the handling difficulties that would arise from processing individually thinned dies.
Solution Approach 2:
The temporary carrier acts as an intermediary that maintains ease of operation during handling of thinned dies. By providing continuous mechanical support across the entire thinned wafer surface, the carrier eliminates the handling difficulties associated with fragile, thin dies, allowing standard manufacturing equipment to process the dies without special precautions.
3Area of stationary object
If multiple dies are stacked to increase density, then the component footprint is reduced, but the stacking process becomes more complex due to die fragility
Solution Approach 1:
The patent applies preliminary thinning to the second wafer before stacking, which enables multiple dies to be stacked in a simplified manner. The temporary carrier maintains die integrity throughout the stacking process, allowing standard stacking equipment to be used without complex handling procedures. This preliminary preparation reduces the overall process complexity despite achieving higher stacking density.
Solution Approach 2:
The temporary carrier serves as an intermediary that simplifies the stacking process by providing mechanical support to thinned dies during all stacking operations. This support structure eliminates the need for complex handling procedures that would otherwise be required to prevent die breakage, thereby reducing process complexity while enabling multiple dies to be stacked to increase density.
Data Source
Figure 1
Figure 2A~2B
Figure 2C
AI summary
Stacked semiconductor devices, semiconductor assemblies, methods of manufacturing stacked- semiconductor devices, and methods of manufacturing semiconductor assemblies. One embodiment of a semiconductor assembly (100) comprises a' thinned semiconductor wafer (110) having an active side releaseably attached to a temporary carrier (130), a back side, and a plurality of first dies at the active side. The individual first dies have an integrated circuit, first through die interconnects (125) electrically connected to the integrated circuit, and interconnect contacts (126) exposed at the back side of the wafer. The assembly further includes a plurality of separate second dies having their front side attached to the back side of corresponding first dies, wherein the individual second dies have integrated circuits, through die interconnects (147) electrically connected to the integrated circuits and contact points (148) at a back side, and wherein the individual second dies have a thickness of approximately less than 100 microns.