Image Sensor Chip Package Adhesive Wire Protection
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Solution Overview
Problem
The existing image sensor chip package fabrication methods are complex and costly due to the need for extensive wire bonding, which exposes wires to contamination and increases the package volume, leading to dust accumulation and potential damage, affecting image quality and reliability.
Innovation Solution
The method involves a carrier with a base and leadframe, where an image sensor chip is mounted in a cavity, connected with wires, and sealed with an adhesive and transparent cover, minimizing the sealing space and protecting the wires and photosensitive area from dust and damage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If bonding wires are used to connect the image sensor chip with conductive pieces, then electrical connection is achieved, but the wires are exposed to contamination and may be damaged by dust-particles
Solution Approach 1:
The bonding wires are nested within the adhesive means, which is applied around the image sensor chip. The adhesive means completely covers and encloses the bonding wires, protecting them from dust-particles and contamination while maintaining electrical connections. This nesting approach eliminates the need for separate wire protection structures.
Solution Approach 2:
The adhesive means acts as a flexible protective shell that completely covers the bonding wires. This thin film-like adhesive layer provides protection against dust contamination while allowing the wires to maintain their electrical function and physical flexibility.
2Ease of manufacture
If a larger space is provided in the package, then wire connection is facilitated, but more dust-particles adhere to the cover and sidewalls
Solution Approach 1:
The harmful factor (dust accumulation problem) is extracted by minimizing the internal space where dust can adhere. The adhesive means is applied to reduce the sealing space volume, removing the environment where dust-particles can accumulate on cover and sidewalls while still providing adequate space for wire connection.
Solution Approach 2:
The adhesive means is applied preliminarily to cover and protect the bonding wires before the cover is sealed. This preliminary protective action prevents dust-particles from adhering to exposed surfaces and falling onto the chip, addressing the dust contamination issue before it can occur during operation.
3Reliability
If extensive wire bonding is performed, then electrical connections are established, but the process becomes complex and costly
Solution Approach 1:
The protective function and the electrical connection function are merged into a single integrated approach. The adhesive means simultaneously serves as the protective covering for wires and as the medium that facilitates wire bonding to the chip pads, eliminating the need for separate protection steps and reducing overall process complexity.
Solution Approach 2:
The adhesive means performs multiple functions: it provides mechanical support for wire bonding, establishes electrical connections, and simultaneously protects the wires from contamination. This multi-functionality reduces the number of separate components and steps required, simplifying the overall fabrication 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 reduces labor and costs by allowing simultaneous fabrication of multiple packages, enhances image sensor reliability, and maintains high image quality by protecting the photosensitive area and bonding wires from contamination.
Implementation Method 1
applying an adhesive means around the image sensor chip and at least partially covering all the wires; and mounting a transparent cover to the carrier, the adhesive means adhering to the cover
Data Source
AI summary
An image sensor package method includes the steps of: first, providing a carrier (30), which includes a base (24) and a leadframe (320). The base has a cavity therein and the leadframe includes a number of conductive pieces; Second, mounting an image sensor chip on the base and received in the cavity, the image sensor having a photosensitive area. Third, providing a plurality of wires, each electrically connects the image sensor chip and a corresponding one of the conductive pieces of the carrier. Fourth, applying an adhesive means around the image sensor chip that at least partially covers all the wires. Finally, mounting a transparent cover on the carrier, where an adhesive means fixes the cover in place.