Flip Chip Pressure Sensor Assembly Eliminating Wire Bonds
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Solution Overview
Problem
The miniaturization of pressure sensors poses challenges in mass manufacturing while maintaining performance standards and production yields, primarily due to the space consumed by wire bonds, which limits further size reduction and introduces mechanical stress issues with underfill materials.
Innovation Solution
The use of flip chip mounting technology to electrically connect pressure sensor dies to substrates, eliminating wire bonds and avoiding underfill materials to reduce mechanical stress, while employing a cover with an aperture and seal to transmit pressure to the sensor diaphragm, and optionally using a gel disk for improved mechanical stabilization and linearity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Length of moving object
If wire bonds are used to electrically connect pressure sensor dies to substrates, then electrical connectivity is achieved, but the sensor size cannot be further reduced and mechanical stress issues arise
Solution Approach 1:
The patent removes wire bonds and underfill materials from the sensor assembly, extracting the problematic elements that prevent further miniaturization and cause mechanical stress. The electrical connection is achieved directly through flip chip mounting where solder balls on the die bottom connect to the substrate, eliminating the need for wire bonds that consume space and add complexity.
2Strength
If underfill materials are used to support the die, then mechanical support is provided, but mechanical stress is introduced to solder joints
Solution Approach 1:
The patent eliminates underfill materials from the assembly by using flip chip mounting technology where the die is directly soldered to the substrate. This removal of underfill materials prevents the introduction of mechanical stress to the solder joints while still providing adequate mechanical support through the solder connections and direct die-to-substrate bonding.
3Length of moving object
If sensor features are reduced in size, then miniaturization is achieved, but manufacturing performance standards and production yields deteriorate
Solution Approach 1:
The patent replaces traditional mechanical wire bonding and underfill support systems with flip chip mounting technology using solder balls. This substitution enables better control over small feature sizes while maintaining manufacturing precision, as the solder ball placement and reflow process provides consistent, reliable connections even at reduced sensor dimensions.
Data Source
AI summary
A flip chip pressure sensor assembly. The flip chip pressure sensor assembly comprises a substrate; a pressure sensor die comprising a sensing diaphragm, the die having a top side and a bottom side that is reverse to the top side, where the top side of the die is electrically connected to the substrate by flip chip mounting technology; a cover defining an aperture disposed over the pressure sensor die, where the aperture defined by the cover aligns with the sensing diaphragm to provide a path for pressure to be transmitted through the aperture to the bottom side of the sensing diaphragm; and a gel disk disposed within the aperture in intimate contact with a bottom side of the sensing diaphragm, where the gel disk is domed above an outer shoulder of a rim defined by the cover.