Stacked Semiconductor Die Assembly With Side-Edge Bond Pads
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Solution Overview
Problem
Traditional semiconductor devices with redistribution layers (RDL) on top and bottom surfaces require excess substrate material for protection, increasing device and assembly heights and costs without enhancing operating capacity.
Innovation Solution
Incorporating raised portions (RDL or 'pad islands') on side edges of semiconductor devices, excluding them from the center top surface, reduces the need for buffer material on the top surface, thereby minimizing device height and material usage while maintaining operating capacity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If traditional RDL structures with excess substrate material are used to protect bond pads, then reliability is improved, but device height increases
Solution Approach 1:
The patent moves the RDL structure from the top surface to the side edges of the device. Instead of having raised pad islands on the top surface that increase height, the bond pads are positioned on vertical side surfaces, transferring the protective structure to a different spatial dimension. This allows bond pad protection while maintaining a lower overall device height.
Solution Approach 2:
The patent applies the RDL protective structure selectively only at the side edges where bond pads are located, rather than across the entire top surface. This localized approach provides necessary protection at critical areas while eliminating excess substrate material from non-critical regions, thereby reducing overall device height.
2Reliability
If excess substrate material is used for buffer portions, then reliability is improved, but manufacturing cost increases
Solution Approach 1:
The patent extracts the RDL protective structure from the bulk top surface material and concentrates it only at the side edges. This removal of excess substrate material from non-essential areas reduces material costs and simplifies manufacturing while maintaining protection where actually needed.
3Reliability
If raised pad islands are placed on center top surface, then bond pad protection is improved, but device height increases
Solution Approach 1:
The patent relocates the raised pad islands from the horizontal top surface to the vertical side edges. This dimensional transition allows the protective structures to provide the same bond pad protection function while occupying lateral space rather than vertical space, thus avoiding height increase.
Data Source
AI summary
A semiconductor device assembly can include an assembly substrate having a top surface with a die stack thereat. The die stack can include a first and a second die, and each dies can include a die substrate with a top and a bottom surface. The top surface can include a first region a first distance from the bottom surface, and a second region a second distance, greater than the first distance, from the bottom surface and with a bond pad thereat. The bottom surface of the first die can bond with the top surface of the assembly substrate, and the bottom surface of the second die can bond with the first region of the first die top surface. In some embodiments, the assembly can further include additional die stacks and/or additional dies within one or more die stacks.