Conductive Jumper Isolation for MEMS Integration
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Solution Overview
Problem
Conventional monolithic integration techniques for MEMS devices with active circuitry result in heat and charge transfer during fabrication, leading to potential breakdown of active devices like CMOS transistors and damage to both active and MEMS devices.
Innovation Solution
The integration method involves forming a thermally and electrically isolated structure using a conductive jumper to connect the passive component's via/interconnect metal stack to the device-side via/interconnect metal stack, ensuring that heat and charge from the plasma etching process are not transferred to the active device, and allowing for controlled charge buildup during fabrication.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If passive components and MEMS devices are formed by layer-by-layer process over semiconductor substrate during BEOL processing, then monolithic integration of passive components with active devices is achieved, but heat and charge from thermal and plasma processes build up and are transferred to active devices through routing paths, causing performance degradation and potential breakdown
Solution Approach 1:
The patent divides the via/interconnect metal stack into two separate stacks: a device-side stack connected to the active device and a passive-component-side stack connected to the passive component. These stacks are electrically isolated from each other during fabrication, preventing heat and charge transfer to the active device while allowing monolithic integration of both active and passive components on the same semiconductor substrate.
Solution Approach 2:
The patent introduces a conductive jumper as an intermediary element that connects the device-side via/interconnect metal stack and the passive-component-side via/interconnect metal stack after the passive component fabrication is complete. This jumper serves as a mediator that enables electrical connection only when needed, while maintaining isolation during the critical fabrication phase to protect the active device from heat and charge damage.
2Ease of operation
If routing paths are established early in the fabrication process to connect MEMS devices with active circuitry, then electrical connectivity is achieved, but the routing paths become conduits for transferring harmful heat and charge from plasma etching processes to active devices
Solution Approach 1:
The patent performs preliminary actions by forming both the device-side via/interconnect metal stack and the passive-component-side via/interconnect metal stack separately and in isolation before establishing their electrical connection. This preliminary separation allows the routing infrastructure to be prepared in advance while preventing harmful interactions during fabrication, and the connection is established only after the passive component fabrication is complete.
3Manufacturing precision
If plasma etching is used to pattern bottom electrode and other electrodes of MEMS device, then precise patterning is achieved, but heat and charge build up during the process and cause damage to both active circuitry and MEMS devices
Solution Approach 1:
The patent extracts the passive-component-side via/interconnect metal stack from the electrical connection to the active device during the fabrication process. By taking out this connection temporarily, the harmful heat and charge generated during plasma etching of the passive component electrodes are prevented from reaching the active device, while the precise patterning of MEMS electrodes is maintained through the plasma process.
Data Source
AI summary
Integration of active devices with passive components and MEMS devices is disclosed. An integrated semiconductor structure includes an active device having a device top electrode connected to a conductive jumper by a device-side via/interconnect metal stack. The integrated semiconductor structure also includes a passive component having a component bottom plate connected to the conductive jumper by a component side via/interconnect metal stack. The component bottom plate is situated at an intermediate metal level higher than the device top electrode, and the conductive jumper is situated at a connecting metal level higher than the component bottom plate. The conductive jumper reduces undesirable charge flow into the active device during fabrication of the passive component. The passive component can be, for example, a MEMS device.