Selective Anti-Stiction Layer Removal for MEMS Eutectic Bonding
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Solution Overview
Problem
The reliability of eutectic bonds in MEMS devices is compromised by native oxide and anti-stiction layers on the eutectic bonding substructure, leading to potential bond failure, as traditional cleaning methods like ion bombardment also remove the anti-stiction layer from MEMS device surfaces, reducing its effectiveness.
Innovation Solution
Selective ion bombardment or plasma treatment is used to remove regions of the native oxide and anti-stiction layers from the eutectic bonding substructure before bonding, improving the reliability of the eutectic bond while maintaining the anti-stiction layer's effectiveness on MEMS device surfaces.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If ion bombardment is used to remove native oxide from eutectic bonding substructure, then bonding reliability is improved, but anti-stiction layer is also removed from MEMS device surfaces
Solution Approach 1:
The patent applies different surface treatments to different regions: the eutectic bonding substructure undergoes ion bombardment or plasma treatment to remove native oxide and anti-stiction layers for reliable bonding, while the MEMS device surfaces retain their anti-stiction layers to prevent stiction. This spatial differentiation of surface properties resolves the contradiction between achieving reliable bonds and maintaining anti-stiction functionality.
2Object-generated harmful factors
If anti-stiction layer is applied to eutectic bonding substructure, then stiction prevention is improved, but bonding reliability deteriorates
Solution Approach 1:
The anti-stiction layer is selectively applied only to regions where stiction prevention is needed (MEMS device surfaces with movable components), while being excluded from the eutectic bonding substructure where reliable bonding is the priority. This localized application strategy eliminates the contradiction by assigning different functional requirements to different spatial regions.
3Reliability
If traditional cleaning methods are used on eutectic bonding area, then bonding reliability is improved, but manufacturing complexity increases
Solution Approach 1:
The anti-stiction layer is applied conformally across all surfaces first, and then a selective removal step is applied only to the eutectic bonding substructure using ion bombardment or plasma treatment. This preliminary application followed by selective removal simplifies the overall process compared to attempting to apply anti-stiction layer only to specific regions from the beginning.
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 method enhances the reliability of the eutectic bond and maintains the anti-stiction layer's effectiveness, preventing stiction of movable components and extending the useful life of MEMS devices.
Implementation Method 1
Selective ion bombardment or plasma treatment is used to remove regions of the native oxide and anti-stiction layers from the eutectic bonding substructure
Implementation Method 2
Selective ion bombardment or plasma treatment is used to remove regions of the native oxide and anti-stiction layers from the eutectic bonding substructure
Implementation Method 3
a cap substrate is eutectically bonded over the MEMS device to the MEMS substrate using the eutectic bonding substructure
Data Source
AI summary
A microelectromechanical systems (MEMS) package includes a eutectic bonding structure free of a native oxide layer and an anti-stiction layer, while also including a MEMS device having a top surface and sidewalls lined with the anti-stiction layer. The MEMS device is arranged within a MEMS substrate having a first eutectic bonding substructure arranged thereon. A cap substrate having a second eutectic bonding substructure arranged thereon is eutectically bonded to the MEMS substrate with a eutectic bond at the interface of the first and second eutectic bonding substructures. The anti-stiction layer lines a top surface and sidewalls of the MEMS device, but not the first and second eutectic bonding substructures. A method for manufacturing the MEMS package and a process system for selective plasma treatment are also provided.