Electroacoustic Module Assembly Without Wafer-to-Wafer Bonding
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Solution Overview
Problem
Existing manufacturing processes for electroacoustic modules face limitations such as reduced flexibility, inability to test ASICs until the process is complete, warpage issues during wafer coupling, and challenges in controlling temperature uniformity during etching, leading to potential electrical contact failures and material incompatibilities.
Innovation Solution
A manufacturing process involving the formation of a dielectric coating region and redistribution structure, followed by reducing the semiconductor body thickness to singulate transduction structures, which are then coupled to the redistribution structure, eliminating wafer-to-wafer bonding and reducing warpage, and avoiding etching on stacked assemblies.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If wafer-to-wafer bonding is used to couple transducers and ASICs, then electrical connections are established, but warpage occurs during the coupling process
Solution Approach 1:
The invention divides the system into separate components: a first wafer containing transducers and a second wafer containing ASICs, which are processed independently and then coupled through bump bonding. This segmentation allows each wafer to be optimized separately and reduces warpage issues during coupling.
Solution Approach 2:
The invention performs preliminary processing of both wafers before coupling, including forming bump structures on the transducer side and corresponding pads on the ASIC side. This preliminary preparation ensures proper alignment and reduces warpage during the final bonding process.
2Ease of manufacture
If a single manufacturing technology is used for both driving and receiving circuits, then process simplicity is maintained, but manufacturing flexibility is reduced
Solution Approach 1:
The invention uses a bump bonding process that is universally applicable to both driving circuits and receiving circuits, regardless of which wafer they are on. This multi-functional approach allows different manufacturing technologies to be used for different circuits while maintaining process simplicity through a common coupling method.
3Reliability
If the semiconductor body thickness is reduced to form thin membranes, then acoustic wave transmission is improved, but substrate vibrations may interfere with module operation
Solution Approach 1:
The invention creates local quality differences by forming thin membranes only in specific regions where acoustic wave transmission is needed, while maintaining thicker substrate regions for structural support and vibration damping. This localized thinning allows acoustic optimization without compromising overall structural stability.
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 process enhances flexibility, prevents warpage, ensures uniform etching, and improves electrical contact reliability, resulting in high-performance electroacoustic modules with improved acoustic wave transmission.
Implementation Method 1
Each of the unit portions (84) comprises a number of respective piezoelectric actuators (56) in contact with the supporting region (39)
Implementation Method 2
The actuator (56) may also function as an acoustic receiver, in which case the piezoelectric effect will be reversed
Data Source
AI summary
A process for manufacturing electroacoustic modules including: forming an assembly with a redistribution structure and a plurality of dice arranged in a dielectric region; forming a wafer with a semiconductor body and a plurality of respective unit portions laterally staggered, each of which includes a respective supporting region, set in contact with the semiconductor body, and a number of actuators; reducing the thickness of the semiconductor body and then selectively removing portions of the semiconductor body so as to singulate, starting from the wafer, a plurality of transduction structures, each including a semiconductor substrate, which contacts a corresponding supporting region and is traversed by cavities delimited by portions of the supporting region that form membranes mechanically coupled to the actuators; and then coupling the transduction structures to the redistribution structure of the assembly.