Organic Substrate Air Cavity Thermal Insulation for OCXO
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Solution Overview
Problem
Current oven-controlled crystal oscillators (OCXO) with microelectromechanical system (MEMS) oscillators face challenges in maintaining constant temperature due to high thermal conductivity of ceramic substrates and additional insulating layers, leading to increased manufacturing costs and power consumption.
Innovation Solution
The use of an organic substrate with air or vacuum cavities as heat conduction retardation zones, which significantly reduces thermal conductivity and power consumption, while maintaining the crystal oscillator and oscillation circuit at a constant temperature.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If ceramic substrates and insulating layers are used to maintain constant temperature, then temperature stability is improved, but thermal conductivity is too high leading to increased power consumption
Solution Approach 1:
The patent changes the thermal conductivity parameter by replacing ceramic substrates with organic substrates having lower thermal conductivity (0.2-1.0 W/mK), and introduces air or vacuum cavities with extremely low thermal conductivity to reduce heat loss while maintaining temperature stability
Solution Approach 2:
The patent creates a composite structure combining organic substrate materials with air or vacuum cavities to achieve optimal thermal insulation properties, where the combination provides better thermal isolation than either material alone
2Temperature
If ceramic substrates with additional insulating layers are used, then temperature control is improved, but manufacturing cost increases
Solution Approach 1:
The patent extracts and eliminates the complex multi-layer insulating structure by using a single organic substrate material with inherently low thermal conductivity, simplifying the manufacturing process while maintaining temperature control functionality
Solution Approach 2:
The patent changes the substrate material parameter from high-cost ceramic to lower-cost organic materials, achieving comparable or better thermal insulation performance at reduced manufacturing cost
3Loss of energy
If high thermal conductivity substrates are used, then heat dissipation is improved, but heat loss from the crystal unit increases
Solution Approach 1:
The patent changes the thermal conductivity parameter of the substrate from high (ceramic) to low (organic materials with 0.2-1.0 W/mK), and introduces air/vacuum cavities with even lower thermal conductivity to minimize heat loss and reduce the power needed to maintain constant temperature
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 reduces heat loss and manufacturing costs by employing organic substrates with lower thermal conductivity than ceramic substrates, effectively maintaining the crystal unit at a constant temperature with reduced power consumption.
Implementation Method 1
a first cavity enclosed by a back surface of the first chip and the first recess... The first cavity is an air cavity or a vacuum cavity
Implementation Method 2
an organic substrate having a first surface... the control chip having a heat source region adjacent to an active surface of the control chip
Data Source
AI summary
A semiconductor package structure includes an organic substrate having a first surface, a first recess depressed from the first surface, a first chip over the first surface and covering the first recess, thereby defining a first cavity enclosed by a back surface of the first chip and the first recess, and a second chip over the first chip. The first cavity is an air cavity or a vacuum cavity.