Optical Interference Filter AlN Layers Reduce Singulation Defects
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Solution Overview
Problem
Optical filters experience singulation defects due to low durability at the interface between layers, leading to chipping, delamination, and damage during the singulation process, which degrades performance and increases manufacturing costs.
Innovation Solution
Incorporating a second layer of aluminum nitride (AlN) between layers of tantalum pentoxide (Ta2O5) and hydrogenated silicon (Si:H) to enhance durability and reduce singulation defects, maintaining filtering performance and reliability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If traditional layer interfaces are used in optical filters, then manufacturing is simpler, but durability is low leading to singulation defects
Solution Approach 1:
An aluminum nitride (AlN) intermediate layer is introduced between the hydrogenated silicon (Si:H) layer and the tantalum pentoxide (Ta2O5) layer. This intermediate layer acts as a mediator that improves adhesion and reduces interface defects, thereby enhancing the overall durability of the optical filter structure without fundamentally changing the manufacturing process.
Solution Approach 2:
The patent employs a composite multilayer structure combining different materials (Si:H, AlN, Ta2O5) with complementary properties. The AlN layer provides mechanical strength and adhesion, while the Si:H and Ta2O5 layers provide optical filtering functionality. This composite approach resolves the contradiction by integrating materials that address both durability and optical performance requirements.
2Reliability
If additional quality control measures are implemented to reduce defects, then reliability improves, but manufacturing cost increases
Solution Approach 1:
The aluminum nitride intermediate layer is incorporated into the layer structure during the initial manufacturing process, before singulation occurs. This preliminary action prevents interface defects and delamination from occurring in the first place, rather than requiring post-manufacturing quality control measures. The structure is designed to be inherently more durable from the outset.
3Ease of manufacture
If the layer structure is simplified, then manufacturing is easier, but singulation defects increase
Solution Approach 1:
Rather than simplifying the entire layer structure, the patent applies a targeted local modification by adding the AlN intermediate layer only at critical interfaces where adhesion problems occur. This localized approach maintains manufacturing simplicity while specifically addressing the singulation defect issue at the most vulnerable points in the structure.
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 improved durability reduces the number of defective filters, increases yield, and decreases manufacturing costs by minimizing the need for additional filters, while maintaining high transmittance and angle shift performance.
Implementation Method 1
Optical interference filter
Data Source
AI summary
In some implementations, an optical interference filter includes a substrate and one or more sets of layers that are disposed on the substrate. Each set of layers includes: a first layer that comprises at least tantalum and oxygen (e.g., a tantalum pentoxide (Ta2O5) material); a second layer that comprises at least aluminum and nitrogen (e.g., an aluminum nitride (AlN) material); and a third layer that comprises at least hydrogen and silicon (e.g., a hydrogenated silicon (Si:H) material). The second layer is disposed between the first layer and the third layer. In some implementations, a first surface of the second layer is disposed on a surface of the first layer, and a second surface of the second layer is disposed on a surface of the third layer.