Stacked Flip-Assembled Chips in Thin Hybrid Substrate
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Solution Overview
Problem
Current technologies face challenges in reducing the size and thickness of semiconductor substrates effectively, particularly for device-stacking and package-on-package methods, which hinders the miniaturization of electronic products and poses risks to expensive chips during substrate fabrication.
Innovation Solution
A hybrid substrate approach using a rigid insulating interposer with high modulus and low-modulus tapes for flip-attached semiconductor chips, where adhesive material holds the chips together, allowing for a thin integrated substrate with excellent electrical performance and mechanical stability, and a flexible fabrication method that can be applied to various semiconductor products.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Length of stationary object
If conventional substrate fabrication methods are used, then manufacturing process is simple, but substrate thickness cannot be reduced effectively and chip yield is at risk
Solution Approach 1:
The chips are pre-assembled onto the substrate before the substrate fabrication is completed. This preliminary assembly allows the expensive known-good chips to be protected from fabrication risks, as the substrate build-up is performed after the chips are already in place, eliminating the risk of chip damage during substrate processing.
Solution Approach 2:
The conventional sequence is inverted: instead of completing substrate fabrication first and then assembling chips, the chips are assembled first and then the substrate is built up around them. This reversal protects the chips from fabrication risks and enables thinner substrate profiles.
2Length of stationary object
If device-stacking and package-on-package methods are used, then board thickness can be reduced, but manufacturing complexity increases and process risks increase
Solution Approach 1:
The manufacturing process is segmented into distinct phases: chip assembly phase, substrate build-up phase, and interconnection phase. This segmentation allows each phase to be optimized independently, reducing overall manufacturing complexity while achieving thin board profiles through vertical stacking.
3Area of stationary object
If substrate area is reduced to shrink product outlines, then product size decreases, but assembly area for chips and components is limited
Solution Approach 1:
The assembly architecture transitions from a two-dimensional planar layout to a three-dimensional vertical stacking configuration. By stacking chips and components in multiple layers vertically, the assembly capacity is dramatically increased without increasing the board footprint, effectively resolving the contradiction between compact size and assembly capacity.
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 approach enables a significant reduction in substrate thickness, enhances product reliability, and allows for faster market introduction of innovative products without requiring chip redesign, while minimizing assembly area and overall system thickness.
Implementation Method 1
Adhesive material holds the tapes parallel to the interposer and the chip surfaces together
Implementation Method 2
Solder balls and discrete components may be attached to the outside surfaces of the tapes
Data Source
AI summary
A semiconductor system having a substrate (101) including a rigid insulating interposer (110) with a high modulus and a top (140) and a bottom (150) low-modulus tape with flip-attached semiconductor chips (120, 130). The assembled chips, with the passive surfaces facing each other, are located in an opening (114) of the interposer, which has a thickness (111) equal to or smaller than the sum of the assembled two chips. Adhesive material (160) holds the tapes parallel to the interposer and the chip surfaces together. Solder balls (180) and discrete components (170) may be attached to the outside surfaces of the tapes.