Sensor Package With Intermediate Carrier For Contamination Protection
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Solution Overview
Problem
Existing sensor packages face challenges with size and contamination issues, as traditional quad flat packages are large and prone to contamination during soldering processes, which can affect sensor functionality.
Innovation Solution
A sensor package design featuring an integrated circuit chip bonded to an intermediate carrier with adhesive connections and solder bond pads, providing protection and miniaturization, eliminating the need for wire bonds and reducing contamination risks during soldering.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a traditional quad flat package with wire bonds is used, then the sensor is protected from contamination, but the package size becomes relatively large compared to the die size
Solution Approach 1:
The patent removes the wire bonds and lead frame from the package structure, extracting only the essential protective and functional elements. The intermediate carrier retains only the necessary opening for sensor access and the bond pads for electrical connection, eliminating unnecessary structural components that increased package size.
Solution Approach 2:
The patent transitions from a wire-bonded three-dimensional structure to a direct-solder bump configuration that reduces vertical height and lateral footprint. The sensor chip is mounted directly on the intermediate carrier with solder bumps, eliminating the need for wire bond routing space and lead frame extensions.
2Area of stationary object
If the chip is directly soldered to a PCB in a CSP package, then the package size is minimized, but the sensor area is exposed to contamination from solder splatter
Solution Approach 1:
The intermediate carrier serves as a mediator between the sensor chip and the PCB. It provides a protective barrier that shields the sensor area from solder contamination while enabling reliable electrical connection through solder bumps on its opposite surface. The carrier's opening is precisely controlled to provide sensor access while maintaining protection.
Solution Approach 2:
The package is segmented into distinct functional zones: the sensor chip area with protected sensor elements, the intermediate carrier with a controlled opening, and the solder bond pad area. This segmentation allows the sensor to be isolated from contamination sources while maintaining electrical connectivity.
3Reliability
If wire bonds are used to connect the chip to the carrier, then electrical connection is achieved, but the package complexity and size increase
Solution Approach 1:
The patent replaces the mechanical wire bonding process with a direct solder bump connection system. Instead of using wire bonds that require bonding equipment and create complex routing, the electrical connection is achieved through solder bumps that are directly attached to the chip pads and connected to the intermediate carrier's bond pads.
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
The solution enables a compact, contamination-free sensor package that protects sensor elements and allows for reliable soldering to a PCB, achieving a near-chip scale package size while ensuring sensor functionality and reliability.
Implementation Method 1
a first surface of the integrated circuit chip is bonded to a first surface of an intermediate carrier by an adhesive
Data Source
AI summary
A sensor package comprises a sensor chip bonded to an intermediate carrier, with the sensor element over an opening in the carrier. The package is for soldering to a board, during which the intermediate carrier protects the sensor part of the sensor chip.