MEMS Device Vacuum Degradation via Getter Layer and Eutectic Bonding
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Solution Overview
Problem
The existing methods for manufacturing MEMS devices using sputtering techniques often result in a reduction of the vacuum degree due to the sealing of rare gases like argon in the film, which affects the performance of the devices.
Innovation Solution
A MEMS device is designed with a bonding layer and wiring layers made of the same metal material, where the rare gas content is less than 1×10^20 atoms/cm^3, and the bonding process involves eutectic bonding between an Al-containing layer and a Ge-containing layer, performed under high vacuum conditions to minimize the introduction of rare gases.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If sputtering technique is used for film formation, then film adhesiveness is improved, but rare gas is sealed in the film causing vacuum degree to be reduced
Solution Approach 1:
The patent extracts and removes the harmful rare gas (argon) that is sealed in the film during sputtering by introducing a getter layer that actively absorbs and traps the rare gas, thereby resolving the vacuum degradation problem while maintaining the sputtering process for good film adhesiveness
Solution Approach 2:
The patent introduces a getter layer as an intermediary substance between the film and the internal space to mediate the interaction with rare gas. The getter layer serves as a trap that captures and holds the rare gas atoms, preventing them from degrading the vacuum without affecting the film's adhesive properties
2Ease of manufacture
If bonding layer and wiring layer are made with same metal material, then manufacturing process is simplified, but rare gas content control becomes more critical
Solution Approach 1:
The patent applies the same metal material (aluminum-containing layer) for both the bonding layer and wiring layer, making the manufacturing process more simple and unified. This multi-functional approach uses a single material system to serve multiple purposes while implementing a getter layer to control rare gas content across all aluminum layers
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 effectively suppresses the reduction of the vacuum degree in the MEMS device, maintaining a higher internal pressure and improving the device's performance by reducing the presence of rare gases in the film layers.
Implementation Method 1
an aluminum-containing layer and a germanium layer in a polymerized state are interposed between the bonding surfaces of a first semiconductor substrate and a second semiconductor substrate and eutectic bonding between the first semiconductor substrate and the second semiconductor substrate is performed by subjecting the bonding surfaces to heating and pressurizing treatment
Implementation Method 2
a sputtering technique, which is excellent in film adhesiveness, has been used for MEMS device in the related art described in Patent Document 1. According to the sputtering technique, since a film is formed by using a rare gas, for example, Ar (argon), a sputtering gas (e.g., Ar) is sealed in the film
Data Source
AI summary
A MEMS device includes a lower substrate having a resonator, an upper substrate disposed to oppose an upper electrode of the resonator, a bonding layer sealing an internal space between the lower substrate and the upper substrate, and wiring layers that contain the same metal material as the bonding layer. Moreover, a rare gas content of each of the wiring layers is less than 1×1020 (atoms/cm3).