PIC Protective Layer in FOI for Clean Light Access
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Solution Overview
Problem
Semiconductor devices with photonic regions face challenges in protecting the photonic regions during manufacturing while ensuring they remain accessible to light stimuli, as existing encapsulation methods either expose them to contamination or hinder functionality.
Innovation Solution
A protective layer, such as a sacrificial photoresist layer or clear/transparent epoxy material, is applied over the photonic region to shield it during manufacturing processes, allowing light access in the final package.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the photonic region is exposed during manufacturing, then light access is enabled for functionality, but the photonic region is vulnerable to contamination and damage
Solution Approach 1:
A protective layer is applied over the photonic region before manufacturing processes begin. This preliminary protective action shields the photonic region from contamination and damage during subsequent manufacturing steps, while the protective layer is designed to be removable or transparent to allow light access when needed.
Solution Approach 2:
The protective layer serves as an intermediary element between the photonic region and the external environment. It mediates by providing physical protection during manufacturing while allowing the photonic region to remain isolated from harmful factors, and can be configured to allow light transmission when protection is no longer needed.
2Object-affected harmful factors
If the photonic region is covered with protective material, then contamination is prevented, but light access is blocked
Solution Approach 1:
The protective layer is applied selectively only over the photonic region rather than the entire device. This localized protection allows different areas to have different properties: the photonic region is protected while other areas remain accessible. The protective layer can also be made with varying transparency characteristics to balance protection and light access requirements.
Solution Approach 2:
The protective layer can be designed with optical properties that allow it to be transparent or translucent to specific wavelengths of light. This enables the protective material to appear opaque or colored for protection during manufacturing, but transmit light effectively when the device is operational, or can be removed/repositioned to allow light access.
3Ease of manufacture
If encapsulation is performed to protect the device, then manufacturing robustness is improved, but the photonic region becomes inaccessible
Solution Approach 1:
The encapsulation structure is segmented to include a dedicated protective layer over the photonic region that is distinct from the main encapsulation body. This segmentation allows the photonic region to be protected during encapsulation while maintaining the ability to access it later, either by making the protective layer removable, reversible, or transparent to light.
Solution Approach 2:
The protective layer over the photonic region is designed to be dynamic rather than fixed - it can be removed, repositioned, or adjusted after encapsulation. This dynamic characteristic allows the photonic region to be protected during manufacturing but accessible during operation, resolving the contradiction between encapsulation robustness and operational accessibility.
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 protective layer ensures the photonic region's integrity and functionality by preventing contamination and damage during manufacturing, enabling reliable operation post-assembly.
Implementation Method 1
A sacrificial photoresist layer may be formed over the photonic region to protect the photonic region during the formation of the Fan-Out Interposer (FOI) package
Implementation Method 2
A clear or transparent epoxy material may be used to allow light transmission to the photonic region while providing protection for the photonic region
Data Source
AI summary
A semiconductor device has a first interconnect structure with an opening in the first interconnect structure. A PIC is disposed over the first interconnect structure with a photonic region aligned with the opening in the first interconnect structure. A plurality of conductive vias is formed at least partially through the PIC. An interconnect component having a plurality of conductive vias is disposed over the first interconnect structure. A plurality of bumps can be formed over the first interconnect structure. A second interconnect structure is disposed over the PIC and interconnect component. A protective layer is disposed within the opening over the photonic region. An electrical component is disposed over the second interconnect structure. The protective layer can have a dam formed over the PIC and an epoxy material disposed within the dam over the photonic region. Alternatively, the protective layer has an epoxy material disposed over the photonic region.