MEMS Differential Sensor Flip-Chip Assembly via Drilled Substrate
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Solution Overview
Problem
The manufacturing of electronic devices with MEMS differential sensors is cumbersome and costly due to the need for wide cavities to accommodate the sensors and allow wire bonding connections, which increases the complexity and expense of the final device.
Innovation Solution
An electronic device design featuring a substrate with a passing opening and MEMS differential sensors with exposed active surfaces, where the sensors are aligned with the substrate's opening and protected by a barrier element during moulding, allowing for compact assembly and reduced alignment complexities through the 'flip-chip' method and moulding of a protective package that leaves the active surfaces exposed.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a wide cavity is used to house the MEMS die and allow wire bonding connections, then the device can be manufactured using conventional processes, but the device size and manufacturing complexity increase
Solution Approach 1:
The patent applies preliminary action by pre-forming the protective package cavity with integrated connection structures (such as through-substrate vias or pre-positioned bonding pads) before mounting the MEMS die. This eliminates the need for post-assembly wire bonding operations, allowing the cavity to be smaller while still enabling electrical connections through the substrate itself.
Solution Approach 2:
The patent merges the protective package cavity with the electrical connection pathway by integrating through-substrate vias or conductive structures directly into the substrate. This combines the functions of mechanical protection and electrical interconnection into a single integrated structure, reducing overall device complexity and size.
2Reliability
If multiple separate components (protective package, cover, wire bonds) are used to encapsulate the MEMS sensor, then the sensor is protected and electrically connected, but the manufacturing cost and process complexity increase
Solution Approach 1:
The patent merges multiple functions into a single integrated protective package structure. The package simultaneously provides mechanical protection, electrical connection pathways (through integrated vias or conductive structures), and sealing functions, eliminating the need for separate covers and wire bonding operations.
Solution Approach 2:
The protective package is designed as a multi-functional component that performs multiple roles: mechanical protection of the MEMS die, electrical interconnection through integrated conductive structures, environmental sealing, and structural support. This universal component reduces the total number of parts and manufacturing steps.
3Ease of operation
If the cavity is designed to accommodate wire bonding operations, then electrical connections can be established, but the alignment precision and manufacturing efficiency decrease
Solution Approach 1:
The patent replaces the mechanical wire bonding process with direct electrical connections through the substrate, such as through-substrate vias or flip-chip bonding. This substitution eliminates the need for precise alignment during wire bonding operations, as the electrical connections are formed through pre-defined pathways in the substrate.
Solution Approach 2:
The electrical connection pathways (vias, conductive structures) are pre-formed in the substrate before MEMS die mounting. This preliminary preparation of connection routes eliminates the need for complex alignment operations during assembly, improving both manufacturing precision and efficiency.
Data Source
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AI summary
Electronic device (1, 1a, 1b, 1c, 1d, 1e) which comprises: a substrate (2) provided with at least one passing opening (5), a MEMS device (7) with function of differential sensor provided with a first and a second surface (9, 10) and of the type comprising at least one portion (11) sensitive to chemical and/or physical variations of fluids present in correspondence with a first and a second opposed active surface (11a, 11b) thereof, the first surface (9) of the MEMS device (7) leaving the first active surface (11a) exposed and the second surface (10) being provided with a further opening (12) which exposes said second opposed active surface (11b), the electronic device (1, 1d, 1e) being characterised in that the first surface (9) of the MEMS device (7) faces the substrate (2) and is spaced therefrom by a predetermined distance, the sensitive portion (11) being aligned to the passing opening (5) of the substrate (2), and in that it also comprises: a protective package (14, 14a, 14b), which incorporates at least partially the MEMS device (7) and the substrate (2) so as to leave the first and second opposed active surfaces (11a, 11b) exposed respectively through the passing opening (5) of the substrate (2) and the further opening (12) of the second surface (10).