3D Interconnect Capacitor Structure With Guard Ring Noise Isolation
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Solution Overview
Problem
The increasing complexity of semiconductor packages, such as System on Integrated Chip (SoIC) and System in Package (SiP), requires improved interconnect structures that can accommodate vertically stacked device dies with different technologies and functions while maintaining reliability and reducing manufacturing costs.
Innovation Solution
The development of an interconnect structure featuring a capacitor with a bowed region and a guard ring, utilizing metal-insulator-metal (MIM) and metal-insulator-metal-insulator-metal (MIMIM) configurations, along with a guard ring to reduce noise and enhance reliability, and methods for their fabrication using conformal deposition and planarization techniques.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If traditional planar capacitor structures are used in interconnect layers, then manufacturing is simple, but capacitance per unit area is limited
Solution Approach 1:
The patent transitions from traditional planar (2D) capacitor structures to three-dimensional vertical capacitor structures extending through multiple interconnect layers. This dimensional change allows capacitance to be accumulated in the vertical direction, significantly increasing capacitance per unit area while managing the complexity through systematic formation processes
Solution Approach 2:
The capacitor structure is formed by nesting multiple conductive plates and dielectric layers vertically within the interconnect structure. Each additional plate-dielectric pair contributes to the total capacitance, creating a nested configuration that maximizes capacitance within the available vertical space without requiring additional lateral area
2Productivity
If vertically stacked device dies are used to increase functionality, then device density improves, but interconnect complexity and noise increase
Solution Approach 1:
The interconnect structure is segmented into multiple functional layers with dedicated capacitor formations at specific locations. This segmentation allows the interconnect structure to handle both signal transmission and noise filtering functions separately, managing complexity by dividing the system into manageable functional segments
Solution Approach 2:
Guard rings are introduced as intermediary structures surrounding the capacitors and interconnect elements. These guard rings act as mediators that electrically isolate adjacent conductors, reduce crosstalk and noise, and provide a controlled impedance environment, thereby managing the complexity introduced by vertical stacking
3Reliability
If guard rings are added around capacitors to reduce noise, then reliability improves, but manufacturing complexity increases
Solution Approach 1:
The guard rings are formed by extending the existing conductor material from the capacitor plates outward in the same deposition step, rather than adding separate guard ring structures. This merging of formation steps reduces the number of discrete manufacturing operations while achieving the noise reduction function
Solution Approach 2:
The guard rings are formed concurrently with the capacitor plates during the same conformal deposition process, before subsequent planarization and patterning steps. This preliminary formation of guard rings integrates them into the overall fabrication flow without requiring additional dedicated manufacturing steps
Data Source
AI summary
Interconnect structures can include a capacitor of specified structure and/or a guard ring which surrounds a capacitor. The capacitor may include a bowed region with an expanded width that permits the inclusion of a void containing air or another gas. Alternatively, the capacitor may be an MIM capacitor or an MIMIM capacitor having a vertical trench and horizontal plates and formed from conformal layers. The guard ring reduces noise which may damage the capacitor. Any combination of these three features may be used to improve capacitance and reliability.