Composite Chiplet Via Structure for Warpage Mitigation
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current IC integration techniques face limitations such as high cost, low insertion efficiency, and increased z-height due to latency and energy inefficiencies in interconnects, particularly in multi-chip packages and wafer-level stacking, which restrict the density and performance of electrical connections between IC chips.
Innovation Solution
The implementation of hybrid direct interconnects with sub-10 micrometer pitch and the use of warpage mitigation structures, including annular structures and structural support layers, to enhance vertical and lateral interconnect densities and mitigate thermal expansion-induced distortion in composite chiplets.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If wafer-level stacking is used to increase interconnect density, then electrical connection density is improved, but manufacturing complexity and cost increase due to stringent die matching requirements and TSV requirements
Solution Approach 1:
The patent divides the interconnection structure into multiple segments: through-die vias for vertical connections, annular stress mitigation structures integrated within the die, and dummy vias in support layers. This segmentation allows each component to be optimized independently, achieving high interconnect density while managing manufacturing complexity through modular design
Solution Approach 2:
The patent incorporates stress mitigation structures (annular rings and dummy vias) during the die fabrication process itself, before die stacking. This preliminary action prevents warpage issues from arising during assembly, eliminating the need for complex post-assembly stress management and reducing overall manufacturing complexity
2Reliability
If through-substrate vias are used to support signaling and power between die, then electrical connectivity is improved, but power and signal delivery become bottlenecked due to low TSV density
Solution Approach 1:
The patent implements different via structures at different locations: through-die vias with annular stress mitigation structures at critical stress points, and dummy vias in support layers at non-critical locations. This local differentiation optimizes electrical connectivity where needed while using simpler structures elsewhere, thereby increasing overall via density without compromising connectivity reliability
Solution Approach 2:
The patent nests multiple functional elements within the via structure: the conductive via itself, surrounded by an annular stress mitigation structure, which is in turn surrounded by insulator material. This nested configuration maximizes the functional density within the via region, providing both electrical connectivity and stress management in a compact footprint
3Adaptability or versatility
If die stacking is performed after thickest chip metallization layers are fabricated, then design flexibility is improved, but interconnect density is limited due to inability to support very fine pitches
Solution Approach 1:
The patent moves the interconnect formation process to the vertical dimension through through-die vias, allowing fine-pitch interconnections to be created after die fabrication. This dimensional transition enables sub-10 micrometer pitch interconnects to be formed through the die thickness rather than laterally, achieving high density while maintaining design flexibility
Solution Approach 2:
The patent performs preliminary fabrication of the die with standard metallization layers, then adds the fine-pitch interconnect structure through via formation and annular structure deposition. This preliminary action sequence allows each stage to be optimized independently, achieving both design flexibility and high interconnect density
4Adaptability or versatility
If multiple IC chips are assembled into a multi-chip package, then functional integration is improved, but warpage and distortion increase due to thermal expansion differences
Solution Approach 1:
The patent implements annular stress mitigation structures at specific locations within the die where thermal stress concentrates, rather than uniformly throughout. This localized approach provides effective warpage compensation where needed while maintaining the overall functional integration benefits of multi-chip packaging
Solution Approach 2:
The patent explicitly addresses thermal expansion effects by incorporating annular stress mitigation structures designed to compensate for differential thermal expansion between stacked dies. These structures accommodate the expansion/contraction movements that occur during thermal cycling, preventing warpage while maintaining functional integration
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 improves the yield and cost-effectiveness of IC integration by increasing interconnect densities and reducing manufacturing overheads, while minimizing warpage and distortion in composite chiplets, thereby enhancing the performance and reliability of integrated circuit devices.
Implementation Method 1
mitigate a transfer of stress, the stress being due at least in part to an expansion or contraction of the conductive via
Implementation Method 2
mitigating warpage caused by thermal compression or contraction of through-dielectric via structures
Data Source
AI summary
Techniques and mechanisms to mitigate warping of a composite chiplet. In an embodiment, multiple via structures each extend through an insulator material in one of multiple levels of a composite chiplet. The insulator material extends around an integrated circuit (IC) component in the level. For a given one of the multiple via structures, a respective annular structure extends around the via structure to mitigate a compressive (or tensile) stress due to expansion (or contraction) of the via structure. In another embodiment, the composite chiplet additionally or alternatively comprises a structural support layer on the multiple levels, wherein the structural support layer has formed therein or thereon dummy via structures or a warpage compensation film.