Low Voltage Reference Generator Using MOS Devices and Interconnect Resistors
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Solution Overview
Problem
The increased density and lower power availability in integrated circuits lead to challenges in temperature sensing, particularly in high-density areas known as 'hotspots', with bipolar-based sensors experiencing unpredictable accuracy and performance changes, leading to product risk and compromised performance.
Innovation Solution
Implementing temperature sensor circuits that utilize resistors with differential temperature coefficients, formed from metal interconnect stacks, to generate a voltage signal indicative of temperature, using a feedback resistor loop to enhance sensitivity and stability, and combining these with MOS devices to generate reference voltages and currents insensitive to temperature variations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If bipolar-based temperature sensors are used in high-density areas, then temperature sensing capability is provided, but accuracy becomes unpredictable and performance changes occur
Solution Approach 1:
The patent changes the fundamental parameters of the temperature sensor by transitioning from bipolar-based sensing to resistor-based sensing with differential temperature coefficients. This parameter change enables accurate temperature measurement in high-density areas without the unpredictable performance changes associated with bipolar sensors, as resistors provide stable and predictable temperature-dependent resistance variations.
Solution Approach 2:
The patent substitutes the bipolar-based sensing mechanism with a resistor-based mechanism that utilizes differential temperature coefficients. This substitution replaces the problematic bipolar device physics with a more stable resistive effect, where the differential change in resistance with temperature provides reliable and accurate temperature sensing without the performance instability of bipolar devices.
2Productivity
If feature sizes decrease and transistor density increases, then circuit functionality increases, but power consumption per unit area increases and thermal output increases
Solution Approach 1:
The patent applies local quality by implementing temperature sensing specifically in high-density hotspots rather than uniformly across the entire IC. The differential resistor-based sensing is strategically placed in areas where high transistor density creates thermal challenges, providing localized temperature monitoring where it is most needed without unnecessarily increasing power consumption in low-density areas.
3Measurement precision
If bipolar-based temperature sensors are used, then temperature monitoring is achieved, but chip area consumption increases and power consumption increases
Solution Approach 1:
The patent employs simple resistor structures that can be easily fabricated using standard CMOS processes, replacing complex bipolar-based sensor structures. These resistor-based sensors require minimal chip area and can be densely integrated, effectively using simple, area-efficient components to achieve the temperature sensing function without the area overhead of bipolar devices.
4Measurement precision
If bipolar devices are used in advanced CMOS processes, then temperature sensing is provided, but manufacturing complexity increases and process compatibility issues arise
Solution Approach 1:
The patent achieves universality by designing a temperature sensing solution that works across all advanced CMOS processes without requiring specialized bipolar device fabrication. The resistor-based differential sensing approach is universally compatible with standard CMOS manufacturing, eliminating process compatibility issues while maintaining accurate temperature sensing functionality across different process nodes and foundries.
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
The proposed solution provides accurate temperature sensing with reduced chip area and power consumption, improved mechanical stress resistance, and the ability to generate reference voltages and currents with low temperature sensitivity, suitable for advanced CMOS processes without bipolar devices.
Implementation Method 1
combining these with MOS devices to generate reference voltages and currents insensitive to temperature variations
Implementation Method 2
generate reference voltages and currents insensitive to temperature variations
Implementation Method 3
utilize resistors with differential temperature coefficients, formed from metal interconnect stacks, to generate a voltage signal indicative of temperature
Implementation Method 4
using a feedback resistor loop to enhance sensitivity and stability
Data Source
AI summary
Techniques for generating reference voltages and reference currents from a supply voltage are disclosed. A disclosed reference voltage and reference current generator circuit includes a combination of transistor (e.g., MOS) devices and interconnect resistors. The interconnect resistors have temperature coefficients that are selected to negate temperature sensitive effects in the transistor devices due to electron mobility temperature behavior in the transistor devices. The interconnect resistors may be implemented as resistor stacks that include interconnected metal layers separated by electrically insulating layers.