3DIC Bonding Via Layout With Dummy Vias for Signal Integrity
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Solution Overview
Problem
The semiconductor industry faces challenges in the technology of three-dimensional integrated circuits (3DICs) due to complexities in forming efficient bonding structures that reduce interconnect lengths and enhance integration density, speed, and bandwidth, while maintaining cost-effectiveness and process simplicity.
Innovation Solution
The method involves forming a 3DIC structure by creating a first and second semiconductor die with bonding dielectric layers, active and dummy bonding vias, and hybrid bonding, where the active bonding via electrically connects the interconnect structure, and dummy bonding vias are used to reduce loading effects and simplify the process, allowing for direct contact and alignment without additional masks, thereby reducing costs and improving yield.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If traditional bonding structures are used in 3DIC fabrication, then the process is more complex and costly, but the interconnect lengths are longer and integration density is lower
Solution Approach 1:
The bonding structure is segmented into distinct functional regions: active bonding vias for electrical connections and dummy bonding vias for mechanical support and stress distribution. This segmentation allows each region to be optimized independently, reducing overall complexity while enabling higher integration density through efficient space utilization.
Solution Approach 2:
The patent transitions from planar 2D bonding to 3D vertical stacking with multiple bonding layers. By adding the vertical dimension with intermediate bonding layers between stacked dies, the structure achieves higher integration density without proportionally increasing process complexity, as the same bonding techniques are applied repeatedly in the vertical direction.
2Manufacturing precision
If additional masks and complex bonding structures are used, then bonding precision can be improved, but manufacturing cost and process complexity increase
Solution Approach 1:
The bonding structure is designed to be self-aligning through the registration features formed during standard CMOS fabrication. The common formation process for active and dummy bonding vias creates inherent alignment references, eliminating the need for additional alignment masks and complex registration steps while maintaining high bonding precision.
Solution Approach 2:
The formation of active bonding vias and dummy bonding vias is merged into a single etching and filling process sequence. By combining these operations that were traditionally performed separately with different masks, the patent reduces process complexity and manufacturing steps while achieving the required alignment precision through the unified process design.
3Reliability
If more bonding vias are added to reduce loading effects, then signal integrity improves, but device complexity and manufacturing difficulty increase
Solution Approach 1:
Active bonding vias and dummy bonding vias are designed with homogeneous dimensions, materials, and formation processes. This homogeneity allows dummy vias to be added to improve signal integrity and reduce loading effects without requiring different process steps or materials, thereby avoiding increases in device complexity and manufacturing difficulty.
Solution Approach 2:
The dummy bonding vias serve multiple functions: they provide mechanical support, distribute stress, improve signal integrity by reducing loading effects on active vias, and maintain structural symmetry. This multi-functionality allows a single structural element to address multiple reliability concerns without proportionally increasing device complexity.
Data Source
AI summary
A semiconductor structure includes: a first die, comprising a first interconnect structure and a first active pad electrically connected to the first interconnect structure; a first bonding dielectric layer over the first die; a first active bonding via in the first bonding dielectric layer, electrically connected to the first interconnect structure; and a plurality of first dummy bonding vias in the first bonding dielectric layer, wherein the first dummy bonding vias laterally surround the first active bonding via and are electrically floating.