Acoustic Wave Substrate Temperature Mapping for IC Hot Spot Detection
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Solution Overview
Problem
Current methods for monitoring integrated circuit (IC) temperature, such as thermal resistors, thermal diodes, and digital temperature sensors, are inefficient as they consume valuable IC real estate and provide inaccurate readings due to placement issues, while remote sensors like laser interferometers struggle to measure subsurface temperatures accurately, leading to performance issues and increased costs.
Innovation Solution
The use of Surface Acoustic Wave (SAW) or Bulk Acoustic Wave (BAW) Microelectromechanical system (MEMS) devices at the periphery of the IC to measure and calculate average substrate density and temperature along predefined paths, allowing for accurate mapping of temperature and detection of hot spots without embedding sensors in active areas.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If thermal resistors, thermal diodes, or digital temperature sensors are incorporated directly into the IC active area, then temperature measurement capability is provided, but valuable IC real estate is consumed and placement accuracy issues arise
Solution Approach 1:
The patent extracts the temperature sensing function from the active IC area by using acoustic wave propagation through the substrate. The transducers are placed at the periphery rather than embedding sensors in the active region, thus providing temperature measurement capability while preserving valuable IC real estate.
Solution Approach 2:
The patent introduces acoustic waves as an intermediary to indirectly measure temperature. Instead of placing thermal sensors directly in the active area, acoustic waves propagate through the substrate and their velocity changes with temperature, allowing remote temperature measurement without consuming active IC real estate.
2Measurement precision
If multiple temperature sensors are spread throughout the active regions, then coverage of hot spots is improved, but IC real estate consumption increases
Solution Approach 1:
The patent segments the temperature measurement function into multiple acoustic wave paths through the substrate. By measuring acoustic velocity along different paths, temperature information from multiple regions is obtained without placing physical sensors at each location, thus achieving broad coverage while consuming minimal IC real estate.
Solution Approach 2:
The patent transitions from point-based sensor placement to path-based measurement in the acoustic domain. Acoustic waves propagate through three-dimensional paths within the substrate, allowing temperature mapping along extended trajectories rather than at discrete points, thereby improving coverage without increasing sensor count.
3Area of stationary object
If remote temperature sensors such as laser interferometers are used, then IC real estate is preserved, but measurement accuracy at subsurface locations is reduced due to heat diffusion by overlying films
Solution Approach 1:
The patent replaces optical measurement methods (laser interferometers) with acoustic wave-based measurement. Acoustic waves propagate through the substrate material itself and are less affected by overlying films, enabling accurate subsurface temperature measurement while preserving IC real estate.
Solution Approach 2:
The patent changes the measurement parameter from optical properties (affected by film diffusion) to acoustic velocity properties of the substrate. Acoustic wave velocity is directly related to substrate temperature and density, providing a measurement parameter that is less susceptible to interference from overlying films.
4Measurement precision
If thermal resistors, thermal diodes, or digital temperature sensors are used, then temperature measurement is enabled, but processing dependencies and calibration requirements increase complexity
Solution Approach 1:
The substrate itself serves as the sensing medium for temperature measurement. The acoustic wave propagation velocity inherently reflects substrate temperature without requiring external calibration, as the relationship between acoustic velocity and temperature is a fundamental physical property of the material.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This approach enables precise, non-invasive temperature mapping and defect detection, reducing processing dependencies and calibration needs, improving IC performance, reliability, and reducing costs by identifying hot spots and defects during manufacturing and operation.
Implementation Method 1
measuring a propagation time that a mechanical propagation wave travels along at least one predefined path in a substrate
Implementation Method 2
measuring a propagation time that a mechanical propagation wave travels along at least one predefined path in a substrate
Implementation Method 3
calculating an average substrate density and temperature along the at least one predefined path as a function of the propagation time and distance
Data Source
AI summary
A method and system to map density and temperature of a chip, in situ, is disclosed. The method includes measuring a propagation time that a mechanical propagation wave travels along at least one predefined path in a substrate. The method further includes calculating an average substrate density and temperature along the at least one predefined path as a function of the propagation time and distance. The method further includes determining a defect or unauthorized modification in the substrate based on the average substrate density being different than a baseline substrate density.