Semiconductor Humidity Sensor Trench Drainage
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Solution Overview
Problem
Existing semiconductor humidity sensors face challenges in rapidly removing condensation without internal heating, as they are prone to water droplets that persist on the sensor region until the temperature rises above the dew point, leading to inefficient operation.
Innovation Solution
A semiconductor humidity sensor device featuring a trench in the coating layer around the sensor region for drainage, combined with a hydrophilic liner and a channel to prevent molding compound intrusion, allowing for effective liquid removal without heating.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a conventional coating layer is used without drainage structure, then the sensor is protected and sealed, but condensation accumulates on the sensor region causing slow recovery
Solution Approach 1:
The coating layer is segmented by introducing a trench structure that divides the continuous coating into regions, creating a drainage pathway. This segmentation allows condensation to be channeled away from the sensor region while maintaining the protective function of the coating layer.
Solution Approach 2:
The solution transitions from a two-dimensional planar coating layer to a three-dimensional structure by adding vertical depth through the trench. This dimensional change creates a drainage channel that enables liquid removal without compromising the sealing function of the coating.
2Reliability
If internal heating is used to remove condensation, then water droplets evaporate quickly, but power consumption increases
Solution Approach 1:
The harmful condensation is extracted from the sensor region through the trench drainage structure. By providing a dedicated drainage pathway, condensation is actively removed from the sensor area without requiring thermal energy for evaporation, thus eliminating the need for power-consuming heating elements.
Solution Approach 2:
The trench structure, which initially appears to compromise the sealing function, actually benefits the device by providing passive condensation drainage. The gravitational force that causes condensation to form also drives it into the trench for removal, converting a potential harm into a beneficial self-draining mechanism.
3Reliability
If the trench is exposed without protection, then drainage is effective, but molding compound can intrude into the sensor region
Solution Approach 1:
The coating layer has different properties in different regions: it remains continuous and sealed in most areas for protection, while locally forming a trench structure for drainage. This local differentiation allows the coating to simultaneously provide sealing and drainage functions without compromising either.
Solution Approach 2:
The trench acts as an intermediary structure between the sensor region and the external environment. It provides a controlled pathway that allows condensation to drain while preventing unwanted intrusion of molding compound, serving as a mediator that balances drainage efficiency with contamination protection.
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
Enables fast and efficient drainage of condensation, enhancing sensor performance by ensuring quick recovery from humidity-related interference without the need for power-consuming heating elements.
Implementation Method 1
A hydrophilic liner is arranged between the main surface and the coating layer. The hydrophilic liner is exposed in the trench.
Data Source
Figure 1~2
AI summary
The sensor semiconductor device comprises a substrate (1) with a main surface (2), a sensor region (3) on or above the main surface, a coating layer (4) above the main surface, and a trench (5) formed in the coating layer around the sensor region. The trench provides drainage of a liquid from the coating layer.