Photosensitive Chip Packaging With Thin Protective Layer
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Solution Overview
Problem
Traditional semiconductor packaging methods using transparent glass covers for photosensitive chip regions suffer from light refraction and reflection losses, and adhesive failure over time, leading to dust contamination and reduced photosensitive performance.
Innovation Solution
A semiconductor packaging method involving a chip substrate with a photosensitive region, pads, and a transparent protection layer applied over the substrate, along with through-holes for pad exposure and electrical connection to a circuit board via a metal rewiring layer, which reduces light loss and prevents dust entry by minimizing the thickness of the protective layer and enhancing adhesion.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a thick transparent glass cover is used to protect the photosensitive region, then protection capability is improved, but light refraction and reflection increase causing energy loss and degraded photosensitive effect
Solution Approach 1:
The patent changes the thickness parameter of the transparent protection layer from thick (traditional glass cover) to thin (micron-level thickness), thereby reducing light refraction and reflection while maintaining protection capability. This parameter optimization directly addresses the contradiction between protection and light energy preservation.
Solution Approach 2:
The patent employs a thin film transparent protection layer instead of a thick rigid glass cover. This thin film structure minimizes light interference while providing sufficient protection, resolving the contradiction between protection capability and light energy loss.
2Reliability
If a thick transparent glass cover is used to protect the photosensitive region, then protection capability is improved, but the structure complexity and adhesion issues increase leading to dust contamination
Solution Approach 1:
The patent merges the transparent protection layer directly with the chip substrate by forming it through spin coating or dispensing processes, eliminating the need for separate adhesive layers and complex assembly steps. This integration simplifies the packaging structure while maintaining protection capability.
Solution Approach 2:
The thin film transparent protection layer is directly formed on the chip substrate, creating a simple integrated structure that eliminates adhesion issues associated with thick glass covers and multiple components, thereby reducing device complexity.
3Reliability
If a thick transparent glass cover connected by glue is used, then initial protection is provided, but over time the glue falls off allowing dust entry and degrading photosensitive effect
Solution Approach 1:
The transparent protection layer is merged with the chip substrate through direct formation processes (spin coating, dispensing), eliminating the adhesive layer that deteriorates over time. This integration ensures long-term durability and maintains protection capability throughout the product lifecycle.
Solution Approach 2:
The transparent protection layer is self-adhering through direct formation on the substrate, eliminating the need for external adhesive materials that can fail over time. This self-integrated structure ensures lasting protection without the degradation issues of glued assemblies.
4Loss of energy
If a thin transparent protection layer is used to minimize light loss, then photosensitive performance is improved, but protection capability may be reduced
Solution Approach 1:
The patent optimizes the thickness parameter of the transparent protection layer to a specific thin range that balances light transmission and protection capability. This parameter optimization ensures minimal light energy loss while maintaining sufficient mechanical and environmental protection.
Solution Approach 2:
The transparent protection layer is formed using composite material approaches (through spin coating or dispensing of protective formulations) that provide enhanced protection properties even at thin thicknesses, resolving the contradiction between thinness for light transmission and sufficient protection capability.
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 method minimizes light refraction and reflection, improves photosensitive performance, and reduces the risk of dust contamination by using a thinner, directly applied transparent protection layer that adheres well to the chip substrate, thereby enhancing the overall imaging effect.
Implementation Method 1
when passing through the transparent glass, light undergoes refraction, reflection and energy loss
Implementation Method 2
when passing through the transparent glass, light undergoes refraction, reflection and energy loss
Implementation Method 3
curing the transparent protection film includes an ultraviolet irradiation, or a baking
Data Source
AI summary
A semiconductor packaging method and a semiconductor package device are provided. The packaging method includes providing a chip. The chip includes a chip substrate having a front surface and a back surface, where the front surface includes a photosensitive region; a plurality of pads disposed at the front surface of the chip substrate and around the photosensitive region, where the chip substrate contains a through-hole formed from the back surface of the chip substrate, and the plurality of pads are exposed from the through-hole; and a transparent protection layer over the front surface of the chip substrate, where the transparent protection layer covers the photosensitive region and the plurality of pads. The packaging method also includes electrically connecting each pad of the plurality of pads to a circuit board through a corresponding metal rewiring layer in the through-hole.