Thin Film Device Fabrication via Bulk Material Bonding and Thinning
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Solution Overview
Problem
Existing methods for fabricating thin-film devices with bulk piezoelectric materials face challenges such as excessive bonding temperatures, cracking, delamination, and manufacturing inefficiencies, particularly when integrating these materials into MEMS devices with heat-sensitive components.
Innovation Solution
A method involving bonding an active material with bulk properties to a substrate having a heat-sensitive component, followed by thinning to form a film layer, which minimizes damage and allows for more integrated and efficient device packaging, using techniques like transient liquid phase bonding and polymer bonding to manage temperature and ensure reliable bonding.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional fabrication methods (sol-gel, sputtering, epitaxial growth) are used to create piezoelectric thin films, then the films can be deposited on substrates, but the piezoelectric coefficients are considerably lower than bulk material properties
Solution Approach 1:
The patent applies preliminary action by bonding the bulk piezoelectric material to the substrate before thinning it. This sequence allows the bulk material to be processed and bonded while in its high-quality state, preserving its superior piezoelectric coefficients, and then thinned to the desired thin-film thickness after bonding. This reverses the conventional approach where thin films are deposited directly with compromised piezoelectric properties.
2Manufacturing precision
If high temperature annealing processes are used to form preferred crystal orientation and initiate piezoelectric properties, then the piezoelectric thin films can be fabricated, but the ability to fabricate on substrates with heat-sensitive components is constrained
Solution Approach 1:
The patent performs the high-temperature processing and piezoelectric property initiation on the bulk material before bonding it to the substrate with heat-sensitive components. This preliminary action allows the bulk material to undergo necessary thermal processing in its robust state, and then the completed bulk material is bonded to the sensitive substrate, avoiding exposure of the sensitive components to high temperatures.
Solution Approach 2:
The patent segments the fabrication process into distinct stages: (1) processing and preparing the bulk piezoelectric material separately, (2) bonding the prepared bulk material to the substrate, and (3) thinning the bonded material. This segmentation allows high-temperature processing to be isolated to the bulk material preparation stage, protecting the heat-sensitive components on the substrate.
3Strength
If bulk piezoelectric materials are bonded directly to devices, then greater electromechanical force and structural strength are achieved, but excessive bonding temperatures cause damage to heat-sensitive components
Solution Approach 1:
The patent applies preliminary action by bonding the bulk piezoelectric material to the substrate before thinning it. This sequence allows the bulk material to be processed and bonded while in its high-quality state, preserving its superior piezoelectric coefficients, and then thinned to the desired thin-film thickness after bonding. This reverses the conventional approach where thin films are deposited directly with compromised piezoelectric properties.
4Manufacturing precision
If thinning is performed before bonding, then the film layer can be formed, but damage to the film layer increases and manufacturing efficiency decreases
Solution Approach 1:
The patent inverts the conventional sequence by bonding the bulk material first and then thinning it, rather than thinning before bonding. This inversion allows the bulk material to be handled in its robust state during bonding, reducing damage risk, and enables more efficient manufacturing by eliminating the need for separate handling and alignment of pre-thinned films during the bonding process.
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 the creation of thin-film devices with bulk material properties while minimizing damage and optimizing processing efficiencies, allowing for the integration of piezoelectric materials into MEMS devices without compromising heat-sensitive components.
Implementation Method 1
using techniques like transient liquid phase bonding and polymer bonding to manage temperature and ensure reliable bonding
Data Source
AI summary
A thin-film device and a method of fabricating the thin-film device are provided herein. The thin-film device comprises a bond layer, a film layer that has bulk material properties, and a substrate that has a heat-sensitive component disposed thereon. The method of fabricating the thin-film device comprises the step of providing an active material that has bulk material properties. The active material is bonded to the substrate through the bond layer. After bonding the active material to the substrate, the active material that is bonded to the substrate is thinned to produce the film layer of the thin-film device. The substrate is provided with the heat-sensitive component disposed thereon prior to bonding the active material to the substrate.