Image Sensor Flip Chip Package Light Blocking
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Solution Overview
Problem
Existing semiconductor packages face challenges in effectively blocking light from contacting the semiconductor device, particularly in image sensor applications, where light exposure can affect signal generation and image quality.
Innovation Solution
A semiconductor package is designed with a cavity within a glass block, where a semiconductor device is bonded and sealed using an opaque filling material to block light, and a substrate is mechanically and electrically coupled to the device through solder or other interconnects, with standoff structures and metal traces providing additional support and electrical connections.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If a transparent sheet of material is used to expose the die to light, then light transmission is improved, but light blocking from side surfaces is insufficient
Solution Approach 1:
The patent applies different optical properties to different regions: the top surface uses transparent material for light transmission, while the side surfaces use opaque material for light blocking. This local differentiation resolves the contradiction by allowing light to pass through where needed (top) while blocking it where harmful (sides).
Solution Approach 2:
The patent introduces an opaque material as an intermediary substance filling the cavity around the semiconductor device. This intermediary blocks light from reaching the side surfaces of the device while allowing the transparent top surface to function normally for light reception.
2Reliability
If wire bonds are used to couple the die to the substrate, then electrical connections are established, but the package footprint remains large
Solution Approach 1:
Instead of using wire bonds that extend outward from the die, the patent inverts the connection approach by using a flip chip configuration where the die is flipped and bonded directly to the substrate through solder bumps. This eliminates the need for external wire bonds and significantly reduces the package footprint.
Solution Approach 2:
The patent merges the electrical connection function with the mechanical bonding function by using solder bumps that simultaneously provide both structural support and electrical connectivity. This consolidation eliminates the need for separate wire bonds, reducing the overall package area.
3Object-affected harmful factors
If the semiconductor device is sealed within a cavity, then light blocking is improved, but manufacturing complexity increases
Solution Approach 1:
The opaque fill material serving as cavity filler also performs the light-blocking function, eliminating the need for separate light-blocking structures. This multi-functionality reduces the overall number of components and simplifies the manufacturing process while maintaining effective light blocking.
Solution Approach 2:
The patent merges the cavity filling function with the light-blocking function by using opaque material that simultaneously performs both roles. This consolidation reduces the number of separate components needed, simplifying the package structure and manufacturing process.
4Reliability
If solder is used to couple the device to the substrate, then electrical connections are improved, but heating-induced stress increases
Solution Approach 1:
The patent introduces an underfill material as an intermediary substance between the solder joints and the surrounding structure. This underfill material acts as a stress buffer that absorbs thermal expansion differences between the solder, die, and substrate, reducing heating-induced stress while maintaining reliable electrical connections.
Solution Approach 2:
The underfill material is applied beforehand to the substrate or die before soldering, creating a cushioning layer that anticipates and mitigates thermal stress. This preventive measure reduces the impact of heating-induced stress on the solder joints and overall package reliability.
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 configuration enhances light blocking, reduces heating-induced stress, and allows for smaller package footprints while maintaining reliable electrical connections, improving the performance and reliability of image sensor devices.
Implementation Method 1
an opaque material may be between a side surface of the semiconductor device and an inner surface of the cavity. The opaque material may be configured to block light from contacting the side surface of the semiconductor device
Implementation Method 2
Pixels in the die then receive the light through the transparent material and generate signals that are processed to form an image
Data Source
AI summary
Implementations of semiconductor packages may include: a semiconductor device included within a cavity within a glass block. The package may also include a substrate coupled with a first side of the semiconductor device and two or more edges of the glass block. A fill material may be included between the substrate and the second conductor device and an opaque material may be between a side surface of the semiconductor device and an inner surface of the cavity. The opaque material may be configured to block light from contacting the side surface of the semiconductor device.