NU 2009-146

Inventors

Matthew Grayson*

Seda Memik

Jieyi Long

Chuanie Zhou

Gracie Kock

Short Description

Integrated On-Chip Thermocouple Array (IOTA) which monitors the thermal distribution across a microchip

Abstract

Northwestern researchers have developed the Integrated On-Chip Thermocouple Array (IOTA) which monitors the thermal distribution across a microchip to an extremely fine resolution in real-time.  IOTA consists of thermocouple sensors fabricated on the microchip.  This invention addresses many of the limitations that current temperature measurement techniques, such as diode and digital CMOS sensors, possess, making it an extremely sensitive and effective technology that further enhances the performance of microchips.  IOTA consists of three unique parts: thermocouple array, thermal reference point circuitry, and a standard ADC.  First, the thermocouple array is compatible with CMOS processing since it uses bimetallic on-chip thermocouples in an array design.  The pure metallic composition of the thermocouples eliminates any sensitivity to temperature variation along routing paths.  Second, the thermocouple leads are located in proximity to a common thermal reference point for the thermocouples.  The temperatures of all thermocouple junctions within the array can therefore be determined relative to an absolute reference temperature at a single point of the chip.  Third, a single ADC unit accommodates multiple thermocouples.  Resource sharing enables a large number of thermocouples to be used without incurring high overhead.  With a large number of thermocouples in the array, IOTA is capable of performing fine-grain runtime thermal characterization of microchips.  Thermocouple voltage signal can be calibrated with high thermal accuracy and high reproducibility.  IOTA scales extremely well. 

Applications

• High performance microchip

Advantages

• Accurately monitors thermal distribution across microchip within 1°C accuracy
• Integrates directly into microchip
• Requires minimal changes to silicon layout
• Maintains accuracy after microchip process and temperature variations
• Requires minimal space for thermal sensing
• Minimizes support circuitry
• Eliminates need to calibrate individual temperature sensors

IP Status

Issued US Patent No. 8,517,605