Anti-Flare Semiconductor Package Structure for CMOS Image Sensors
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Solution Overview
Problem
Current CMOS image sensor chip scale packages suffer from flare issues due to light entering from non-sensor areas, which degrades image quality as it reflects off metal structures within the package.
Innovation Solution
The implementation of a semiconductor package design that includes an optically transmissive lid coupled to a semiconductor die through dams, with a light blocking material extending from the die to the lid, featuring recesses and indentations to prevent light from entering non-sensor areas, and a redistribution layer, through silicon vias, passivation layer, solder mask, and solder bumps to enhance protection and functionality.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a transparent glass covers the entire chip, then the package structure is simple and cost-effective, but light enters from non-sensor areas causing flare that degrades image quality
Solution Approach 1:
The patent segments the lid structure by introducing recesses in the transparent lid that correspond to non-sensor areas. This segmentation allows different regions of the lid to have different optical functions: the main lid remains transparent for sensor area light transmission, while the recessed portions block stray light from non-sensor areas, thereby reducing flare without compromising manufacturing simplicity
Solution Approach 2:
The patent applies local quality by creating specific recesses only in the portions of the lid that correspond to non-sensor areas. The lid maintains its transparent property over the sensor area while having light-blocking characteristics in the recessed non-sensor regions. This localized modification addresses the flare issue without requiring complete opacity or complex structural changes across the entire lid
2Object-affected harmful factors
If light blocking material is added around the die, then stray light from non-sensor areas is blocked, but the device complexity increases
Solution Approach 1:
The patent merges the light-blocking function with the existing lid structure by forming recesses directly in the transparent lid material. Instead of adding separate light-blocking components around the die, the lid itself is shaped to include integrated recesses that perform the light-blocking function. This merging approach reduces device complexity by eliminating additional components while still achieving effective stray light blocking
Solution Approach 2:
The transparent lid serves multiple functions: it provides mechanical protection for the sensor, allows light transmission to the sensor area, and through its recessed portions, blocks stray light from non-sensor areas. This multi-functionality reduces the need for separate dedicated light-blocking components, thereby simplifying the overall device structure while effectively addressing the stray light problem
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 design effectively prevents flare by ensuring that light only enters the package through the active sensor area, thereby improving image quality and reliability of the semiconductor package.
Implementation Method 1
a light block material around the semiconductor package extending from the first side of the semiconductor die to a second side of the optically transmissive lid
Data Source
AI summary
Implementations of semiconductor packages may include: a semiconductor die having a first side and a second side. A first side of an optically transmissive lid may be coupled to the second side of the semiconductor die through one or more dams. The packages may also include a light block material around the semiconductor package extending from the first side of the semiconductor die to a second side of the optically transmissive lid. The package may include an opening in the light block material on the second side of the optically transmissive lid that substantially corresponds with an active area of the semiconductor die.