Selective MEMS Cavity Outgassing for Pressure Control
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Solution Overview
Problem
MEMS devices often face performance issues due to equal cavity pressures after bonding, where one MEMS device may require a different optimal pressure range than the other, leading to reduced performance.
Innovation Solution
Forming an outgas layer on one cavity but not the other to adjust pressures individually, using materials like silicon dioxide or aluminum oxide, to optimize the pressure within the optimal range for each MEMS device.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If bonding is performed to integrate MEMS devices, then device integration is achieved, but cavity pressures become equal leading to reduced performance
Solution Approach 1:
The patent divides the single pressure control system into separate pressure control mechanisms for each cavity by introducing selective outgas layers. Each cavity can now have independent pressure characteristics through the presence or absence of outgas layers, allowing individual optimization while maintaining integrated device structure.
Solution Approach 2:
The patent applies different properties to different cavities by selectively forming outgas layers in specific cavities based on their pressure requirements. Cavities requiring higher pressures receive outgas layers while others do not, creating local differentiation in pressure control characteristics.
2Reliability
If outgas layer is added to one cavity, then pressure optimization for that cavity is achieved, but device complexity increases
Solution Approach 1:
The outgas layers automatically regulate cavity pressures through controlled outgassing during or after bonding processes. The layers self-regulate pressure without requiring external active control mechanisms, maintaining simplicity while achieving pressure optimization.
Solution Approach 2:
The patent controls pressure by adjusting the thickness and material properties of outgas layers rather than adding complex mechanical pressure control systems. By changing the physical parameters of the outgas layer (thickness, material composition), precise pressure control is achieved with minimal structural complexity.
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
Improves the performance of one MEMS device without affecting the other by controlling pressure through the outgas layer thickness and material selection.
Implementation Method 1
heating the outgas layer to cause an outgas species to release into the first cavity from the outgas layer
Data Source
AI summary
The present disclosure relates to an integrated chip including a semiconductor device substrate and a plurality of semiconductor devices arranged along the semiconductor device substrate. A micro-electromechanical system (MEMS) layer overlies the semiconductor device substrate. The MEMS layer includes a first moveable mass and a second moveable mass. A capping layer overlies the MEMS layer. The capping layer has a first lower surface directly over the first moveable mass and a second lower surface directly over the second moveable mass. An outgas layer is on the first lower surface and directly between the first pair of sidewalls. A lower surface of the outgas layer delimits a first cavity in which the first moveable mass is arranged. The second lower surface of the capping layer delimits a second cavity in which the second moveable mass is arranged.