Monolithic CMOS Microsystems for Structural, Chemical and Bio Hazard Detection

          

Introduction:

The project "Monolithic CMOS Microsystems for Structural, Chemical and Bio Hazard Detection" is a 3 years research project funded by Ignite (previously National ICTRnD Funds Pakistan) to the project's PI Prof. Dr. Syed Arsalan Jawed and the PIO Karachi Institute of Economics and Technology (KIET).

The scope of this project includes monolithic design of several Microsystems (micro-Sensor + micro-Electronics) in a single CMOS die exploiting the upcoming trends of direct integration of mechanical and optical elements in CMOS microchip right at the time of manufacturing at the fabrication facility. In other words, it involves the design of mechanical and opto-electrical part of the mentioned sensors along with their electronics readout circuits (ROC). The targeted application of the proposed sensor-fusion is structural-, chemical- and bio-hazard detection/prediction. Vibration signature analyses using MEMS accelerometers along with hot-spot analyses (HSA) using low-cost IR imagers is intended for structural health monitoring(SHM), i.e. leakage detection in pipelines and structural life expectancy in bridges. Chemical MEMS sensors can be used to detect hazardous gas leakages in a short-time with a high-sensitivity in ppm concentration. Bio-MEMS sensors are intended for an efficient assay of presence and growth of potentially life-threatening air-borne and water-borne pathogens in a time-efficient manner with high specificity as compared to the conventional in-vitro tests. The development cycle of this system encompasses not only the complete analog and mixed signal IC design and characterization cycle but also the design of MEMS and opto-electrical sensors in their respective domains. This monolithic multi-sensor mire-system can be employed as a sensing node on a wireless-sensor-network (WSN) node in conjunction with off-chip connectivity and controller modules.

 

(a) 3D Illustration of the CMOS MEMS Multi-Sensor Chip Design containing Bio-MEMS, Accelerometer, Chemical Sensor and IR Imager in a 5x4 mm2 area

 

(b)  Illustration of the CMOS MEMS Multi-Sensor Chip Design with Disparate Packaging Requirements for each Sensor

Fig:  Illustration of the Designed CMOS MEMS Multi-Sensor Fusion Chip

 

Design Challenges:

  • Designing the Microsystems using emerging CMOS MEMS technologies, i.e. designing the micro-mechanical and optical components with a limited-freedom of materials by using the metal layers, insulator layers and other intermediate layers of the selected CMOS process with a minimal post-silicon-processing of the die. This would require re-design and customization of the standard MEMS/opto-electrical structures and consequently their readout electronics.
  • Limited but evolving CAD tool support for the upcoming CMOS MEMS processes where different tools have to be interoperated to have reliable simulation results before the expensive Microsystem manufacturing.
  • The in-lab characterization of the complete system requires very specific and high-end instrumentation in a controlled environment.
  • The monolithic integration of all the Microsystems inside a single die or inside a package while catering for different packaging requirement arising from each microsystem. For example, MEMS accelerometers require a hermetic sealing while the Micro bolometer require an optical filter window at the front. The Bio-MEMS requires pathogens-sensitive surface to be available outside the package for the pathogen to interact with the microchip.
  • Design Challenges of Functional Subcomponents include:
    • Accelerometer: Single Proof Mass with Tri-Axial sensitivity to achieve an area efficient implementation.
    • IR Imager / Chemical Sensor: Uncooled low-cost micro bolometer based IR detection with on-chip optical filters for selective adsorption analysis with minimal post-processing of the CMOS die.
    • BioMEMS Sensor: enabling both air-borne and water-borne detection with a near real-time assay and highly selective antigen bonding either labeled or label-free.
 

 

Salient Features

  • Early Hazard Detection to Trigger Preventive-Measures using Smart-Fusion of Micro-Sensor-Systems
    • Monolithically integrated inside a CMOS Microchip
    • Three types of sensor-systems are targeted:
      • Accelerometer
      • IR imager/Chemical Sensor
      • BioMEMS Sensor

 

Targeted Types of Hazards

  • Structural-Hazard (leakages in water/oil pipelines or collapse of bridges/buildings)
  • Chemical-Hazard (gas leakages, gases concentration/warfare gases in a chemical attack)
  • Bio-Hazard (harmful pathogens detection in real-time / counter-bio-terrorism)

Technology

CMOS Integrated Circuit (150nm - 350nm) which is Low-cost and Batch-Producible in Millions.

Design Scope

Micro-Sensors & Electronic Readout Interfaces (ROI) design in CMOS Process.

Application Scenario

In a Wireless-Sensor-Network as a miniaturized multi-sensor IC node

Advantages of Multi-Sensor Perspective

Develop a context aware understanding of the scenario

Advantage of Monolithic Integration

Multifaceted specs can be addressed together in design-space

Novelty

Monolithic integration and functional enhancements of multiple micro-Systems’ designs

Impact

Cost-Effective and Wide-Spread Monitoring of major lifeline systems and resources of society, considerably improving quality of life and minimize damage in case of an hazard occurrence

International Partners

King Abdul Aziz City of Science and Technology (KACST), KSA

Potential Customers

Hospitals, City Government, Oil/Gas/Water Companies, Domestic Users