Double-Sided IC Stabilizing Cage for Crack and ESD Protection
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Solution Overview
Problem
Double-sided integrated circuit structures face challenges such as mechanical cracking and electrostatic discharge during fabrication, particularly during dicing, due to the weakness of active device layers and the lack of effective protection mechanisms across these layers.
Innovation Solution
The implementation of a double-sided integrated circuit structure with a metal body that includes a crack stop, electrostatic guard ring, crack sensor, and fill structure, which provides mechanical reinforcement and electrical isolation to prevent cracking and electrostatic discharge by embedding metal portions in dielectric layers and using vias to interconnect them through the active device layer.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a double-sided integrated circuit structure is used to increase metal trace density, then the circuit capacity and functionality are improved, but the mechanical strength and stability of the structure deteriorate
Solution Approach 1:
The patent employs a composite material system consisting of metal traces embedded in dielectric layers, with the active device layer sandwiched between frontside and backside structures. This composite construction allows the structure to achieve both high circuit capacity through multiple metal layers and adequate mechanical strength through the integrated dielectric-metal-dielectric stacking architecture.
2Productivity
If the active device layer is made thinner to increase transistor density, then the integration density is improved, but the resistance to mechanical cracking deteriorates
Solution Approach 1:
The active device layer is implemented as a thin film structure that is mechanically supported by the surrounding dielectric layers and metal traces. The dielectric layers act as protective shells that constrain and support the thin active device layer, preventing mechanical cracking while maintaining high integration density.
Solution Approach 2:
The dielectric layers serve as intermediary materials between the metal traces and the active device layer. These dielectric intermediaries provide mechanical support and stress distribution, protecting the thin active device layer from cracking caused by thermal expansion differences and mechanical stresses during fabrication and operation.
3Reliability
If metal layers are increased in number and density to overcome leakage and parasitic effects, then circuit performance is improved, but the complexity of fabrication and structure increases
Solution Approach 1:
The patent segments the circuit functionality into frontside and backside structures, each with dedicated metal layers for specific functions (signal interconnection vs. power delivery). This segmentation allows independent optimization of each metal layer stack, simplifying fabrication processes while achieving high overall circuit performance through coordinated operation of both sides.
4Device complexity
If dedication of function to front versus back sides is implemented to simplify wiring, then wiring complexity is reduced, but the structural stability during dicing deteriorates
Solution Approach 1:
The patent merges the frontside and backside structures into a single integrated double-sided device, with the active device layer acting as a common substrate that mechanically binds both sides together. This merging creates a unified structure where the dedicated functional layers on each side are mechanically reinforced by their integration, improving stability during dicing and handling while maintaining simplified wiring architecture.
Data Source
AI summary
An exemplary structure includes a semiconductor substrate; a plurality of first dielectric layers at a top side of the substrate; an active device layer at a top side of the first dielectric layers; a plurality of second dielectric layers at a top side of the active device layer; and a metal body. The body includes a first portion that is embedded in the plurality of first dielectric layers. The first portion comprises a first layer of first metal. The body further includes a second portion that is embedded in the plurality of second dielectric layers. The second portion comprises a first layer of second metal. A plurality of vias interconnect the first portion to the second portion through the active device layer. The first layer of the first portion mechanically connects the plurality of vias and the first layer of the second portion mechanically connects the plurality of vias.