Piezo-Compensation Circuit for Semiconductor Sensors
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Solution Overview
Problem
Integrated semiconductor circuits face performance degradation due to mechanical stress-induced piezo-effects, which alter electric parameters such as resistance and magnetic sensitivity, making it challenging to maintain consistent sensor accuracy across varying environmental conditions.
Innovation Solution
A compensation system is developed that generates partial compensation signals with different mechanical stress dependencies, combined and adjusted based on temperature detection to form a corrected deviation signal, which is then used to evaluate and provide a compensation signal for mechanical stress acting on the semiconductor circuit substrate, thereby reducing the impact of piezo-influences on sensor readings.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If mechanical mounting and encapsulation methods are used to protect the semiconductor chip, then the chip is protected from environmental influences, but mechanical stress is introduced that degrades sensor accuracy through piezo-effects
Solution Approach 1:
The patent segments the compensation task by using multiple independent sensors (first and second sensors with different stress dependencies) to measure different aspects of the mechanical stress, allowing the system to isolate and compensate for piezo-effects while maintaining protection
Solution Approach 2:
The patent implements feedback by continuously monitoring the output signals from multiple sensors, comparing them to detect stress-induced deviations, and applying compensation based on the detected mechanical stress to maintain measurement accuracy
2Measurement precision
If multiple sensors with different stress dependencies are used to compensate for mechanical stress, then compensation accuracy is improved, but device complexity increases
Solution Approach 1:
The patent applies local quality by selecting sensors with specifically different stress dependencies (one with positive piezo-coefficient and one with negative piezo-coefficient) positioned to experience the same mechanical stress, allowing targeted compensation of piezo-effects through their complementary responses
3Measurement precision
If temperature detection and correction processing are implemented, then temperature-dependent errors are minimized, but processing complexity increases
Solution Approach 1:
The patent applies preliminary action by detecting temperature in advance and using it to pre-correct the output signals from the sensors before final evaluation, preventing temperature-dependent errors from affecting the final measurement rather than correcting them after the fact
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 enhances the accuracy of stress determination and compensation, minimizing temperature-dependent errors and process-induced scatterings, resulting in improved measurement accuracy and stability of semiconductor sensors.
Implementation Method 1
the piezo-resistive effect indicates generally how the specific ohmic resistance of the respective semiconductor materials behaves under the influence of a mechanical strain
Implementation Method 2
The piezo-Hall effect describes the dependence of the Hall constant of the semiconductor material on the mechanical strain state in the semiconductor material
Implementation Method 3
Changes of the characteristic curves of diodes and bipolar transistors result, among others, from the piezo-junction effect
Data Source
AI summary
A compensation signal, which derives the mechanical stress, which acts on an integrated semiconductor circuit, from two partial compensation signals, which are generated by semiconductor elements with different stress characteristics, can be determined in more detail when the temperature dependence of a ratio of the partial compensation signals is also considered, wherein particularly a deviation of the ratio of the partial compensation signal to an ideal ratio is considered. Thereby, the rise in accuracy of the stress determination results from determining a deviation of the partial compensation signals, on which the stress determination is based, from a nominal behavior in a stress-free state, so that the deviation of the nominal behavior, which can be based, for example, on a variation of the process parameters in a production process of a semiconductor circuit, can also be considered, in addition to the known temperature behavior.