eWLB MEMS Gas Sensor Thermal Capacity Reduction
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Solution Overview
Problem
MEMS gas sensors with semiconductor substrates near heating elements suffer from wasted energy and limited performance due to the thermal capacity of these substrates, which can hinder the efficient sensing of gas concentrations.
Innovation Solution
The implementation of MEMS gas sensors packaged in an embedded wafer level ball grid array (eWLB) package without semiconductor substrates, where the sensors are supported by the molding compound and embedded in an electrically insulating material, reducing thermal capacity and enhancing heating efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If semiconductor substrates are used to support MEMS gas sensors near heating elements, then structural support is provided, but thermal capacity increases causing wasted energy and limited performance
Solution Approach 1:
The patent removes the semiconductor substrate from the sensor structure, extracting the harmful thermal mass while retaining the essential sensing functionality. The sensor is supported directly by the molding compound in an eWLB package, eliminating the substrate that caused energy waste and performance limitations.
2Stability of the object's composition
If semiconductor substrates are used to support MEMS gas sensors, then mechanical stability is provided, but heating efficiency is reduced due to thermal capacity
Solution Approach 1:
The semiconductor substrate is extracted from the structure, removing the thermal barrier that reduced heating efficiency. The sensor elements are now directly supported by the molding compound, allowing heat to be applied more efficiently without the substrate's thermal mass interfering with the heating process.
3Ease of manufacture
If semiconductor substrates are used in the sensor structure, then fabrication support is provided, but gas sensing speed is limited
Solution Approach 1:
The substrate is removed to eliminate the thermal and physical barrier that slowed gas sensing response. The sensor is now in direct contact with the environment through the eWLB package structure, enabling faster gas molecule interaction and quicker sensing response times.
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 improves the performance of MEMS gas sensors by reducing thermal capacity and enabling faster gas sensing, while maintaining a compact and cost-effective package design.
Implementation Method 1
Some gas sensors measure the resistance through a gas sensitive layer. For example, a humidity sensor may measure the resistance through a sensitive layer that absorbs water moisture from the air. As the water moisture is absorbed into the sensitive layer, the resistance of the layer is altered based on the humidity. Such humidity sensors may also include a heating element for use with the gas sensor.
Data Source
AI summary
According to an embodiment, a sensor package includes an electrically insulating substrate including a cavity in the electrically insulating substrate, an ambient sensor, an integrated circuit die embedded in the electrically insulating substrate, and a plurality of conductive interconnect structures coupling the ambient sensor to the integrated circuit die. The ambient sensor is supported by the electrically insulating substrate and arranged adjacent the cavity.