Isolated Active Temperature Regulator for DRG MEMS Die
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Solution Overview
Problem
Disc resonator gyroscopes face issues with temperature sensitivity and mechanical stress due to coefficient of thermal expansion mismatch between the die and the leadless chip carrier package, leading to unstable sensor dynamics and sensitivity to ambient conditions, particularly in space applications.
Innovation Solution
A micromachined thermal and mechanical isolator with two layers, including a top layer with a resistive heater and temperature sensor, and a bottom layer with mechanical isolation beams, is inserted between the MEMS die and the LCC package to reduce thermal and mechanical stress, using semiconductor materials like oxidized silicon and fused silica for improved isolation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If the MEMS die is rigidly mounted to the LCC package, then mechanical stability and alignment are improved, but thermal stress and sensitivity to ambient temperature changes increase
Solution Approach 1:
A two-layer isolator structure is introduced between the MEMS die and LCC package. The top layer provides thermal isolation while the bottom layer provides mechanical isolation. This intermediary structure decouples the thermal and mechanical pathways, allowing the die to be thermally isolated from ambient temperature changes while maintaining mechanical stability through the isolator's structural support.
Solution Approach 2:
The isolator employs composite material construction with two distinct layers made from different materials optimized for their specific functions. The top layer material is selected for thermal isolation properties, while the bottom layer material is selected for mechanical isolation properties. This composite approach allows simultaneous optimization of thermal and mechanical performance that cannot be achieved with a single material.
2Object-affected harmful factors
If the MEMS die is isolated from the LCC package, then temperature sensitivity is reduced, but mechanical support and alignment precision may deteriorate
Solution Approach 1:
The isolator acts as a precision intermediary that maintains alignment while providing isolation. The structured design with controlled geometry and material properties enables the isolator to support the die in a precise position relative to the package, maintaining alignment accuracy despite the decoupling from direct rigid mounting.
3Device complexity
If a simple mounting structure is used, then device complexity is reduced, but isolation performance against thermal and mechanical stress deteriorates
Solution Approach 1:
The mounting structure is segmented into two functional layers: a top layer dedicated to thermal isolation and a bottom layer dedicated to mechanical isolation. This segmentation allows each layer to be optimized for its specific function, achieving superior overall isolation performance compared to a single undivided mounting structure, while keeping the added complexity manageable through modular design.
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 solution significantly reduces temperature sensitivity and mechanical stress, enabling cost-effective and power-efficient inertial sensors suitable for compact space navigation solutions with improved performance compared to existing systems.
Implementation Method 1
a first layer with an active temperature regulator comprising a built-in heater
Implementation Method 2
a first layer with an active temperature regulator comprising a built-in heater and temperature sensor
Implementation Method 3
The isolator may be inserted between a MEMS die of a disc resonator gyroscope (DRG) chip and the leadless chip carrier (LCC) package to isolate the die from stress and temperature gradients
Implementation Method 4
a second layer having mechanical isolation beams supporting the die
Data Source
AI summary
A micromachined thermal and mechanical isolator for MEMS die that may include two layers, a first layer with an active temperature regulator comprising a built-in heater and temperature sensor and a second layer having mechanical isolation beams supporting the die. The isolator may be inserted between a MEMS die of a disc resonator gyroscope (DRG) chip and the leadless chip carrier (LCC) package to isolate the die from stress and temperature gradients. Thermal and mechanical stress to the DRG can be significantly reduced in addition to mitigating temperature sensitivity of the DRG chip. The small form can drastically reduce cost and power consumption of the MEMS inertial sensor and enable new applications such as smart munitions, compact and integrated space navigation solutions, with significant potential cost savings over the existing inertial systems.