Room-Temperature SiO2 Bonding via Transparent Intermediary Layer
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Solution Overview
Problem
The challenge in manufacturing optical MEMS devices is achieving room-temperature bonding with SiO2 base materials while maintaining practical bonding strength and optical transparency, as existing methods often require heat treatment and result in heat strain due to thermal expansion coefficient differences between substrates, and conventional room-temperature bonding methods fail to achieve sufficient bonding strength for SiO2 materials.
Innovation Solution
A device and manufacturing method involving a bonding functional intermediate layer made from optically transparent materials like aluminum oxide, titanium dioxide, or zirconium dioxide, applied between SiO2 and silicon or compound semiconductor substrates, allowing for room-temperature bonding with practical bonding strength and maintaining optical transparency by selecting materials that are different from the main components of the substrates.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If heat treatment is applied during bonding, then bonding strength is improved, but heat strain is generated due to thermal expansion coefficient differences between substrates
Solution Approach 1:
The patent changes the temperature parameter from high temperature (heat treatment) to room temperature bonding, eliminating thermal expansion differences between SiO2 and silicon substrates. This is achieved through surface activation treatments and controlled bonding pressure at ambient conditions, resolving the heat strain issue while maintaining bonding strength
Solution Approach 2:
The patent introduces intermediate layers or surface treatments as mediators between the SiO2 substrate and silicon substrate. These intermediates facilitate bonding at room temperature by creating compatible surface properties, eliminating the need for high-temperature heat treatment that causes thermal expansion mismatch
2Strength
If heat treatment is applied during bonding, then bonding strength is improved, but manufacturing time is increased due to heating and cooling cycles
Solution Approach 1:
The patent changes the temperature parameter from high temperature to room temperature, eliminating the time-consuming heating and cooling cycles. Room temperature bonding with surface activation achieves adequate bonding strength without thermal processing, significantly reducing manufacturing time and increasing productivity
3Productivity
If room-temperature bonding is applied, then manufacturing time is reduced, but bonding strength is insufficient for SiO2 base materials
Solution Approach 1:
The patent applies preliminary surface activation treatments to the SiO2 substrate before bonding. This preliminary action modifies surface properties (creating dangling bonds or active groups) that enable strong room-temperature bonding without requiring high-temperature heat treatment, thus achieving both fast processing and adequate bonding strength
Solution Approach 2:
The patent changes surface physical and chemical parameters through activation treatments, transforming the SiO2 surface from non-reactive to reactive at room temperature. This parameter change enables strong bonding without thermal processing
4Reliability
If conventional room-temperature bonding is applied to SiO2, then heat strain is avoided, but bonding strength is insufficient
Solution Approach 1:
The patent applies preliminary surface activation to SiO2 before bonding, creating reactive sites that enable strong room-temperature bonding. This preliminary treatment resolves the insufficient bonding strength issue while maintaining the reliability advantage of avoiding heat treatment
Solution Approach 2:
The patent changes surface chemical parameters of SiO2 through activation, enabling strong bonding at room temperature without thermal processing, thus maintaining reliability while improving bonding strength
5Strength
If adhesive or solder is used for bonding, then bonding strength is improved, but interface physical properties are deteriorated
Solution Approach 1:
The patent extracts and eliminates adhesive or solder materials from the bonding interface. By using direct substrate-to-substrate bonding with surface activation, it achieves strong bonding without intermediate materials, preserving favorable interface physical properties and reliability
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 enables SiO2 base material bonding with practical bonding strength and excellent optical transmission characteristics, reducing layout restrictions and manufacturing time, while avoiding heat-related issues and optical attenuation, thus enhancing the reliability and durability of optical MEMS devices.
Implementation Method 1
a sputtered first surface of the first substrate is contacted with a sputtered second surface of the second substrate
Data Source
AI summary
A device is provided with: a first substrate mainly containing silicon dioxide; a second substrate mainly containing silicon, compound semiconductor, silicon dioxide or fluoride; and a bonding functional intermediate layer arranged between the first substrate and the second substrate. The first substrate is bonded to the second substrate thorough room temperature bonding in which a sputtered first surface of the first substrate is contacted with a sputtered second surface of the second substrate via the bonding functional intermediate layer. Here, the material of the bonding functional intermediate layer is selected from among optically transparent materials which are oxide, fluoride, or nitride, the materials being different from the main component of the first substrate and different from the main component of the second substrate.