Silicon Polymer Optical Waveguides Thermal Stress Resistance
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Solution Overview
Problem
Silsesquioxane-based optical waveguides in printed wiring boards are prone to cracking and lifting due to thermal stresses, leading to increased optical losses and reduced reliability under varying thermal conditions.
Innovation Solution
A composition comprising a condensation product of specific silicon-containing reactants and a photoactive component, which forms a polymer suitable for optical waveguides, enhancing their thermal stability and reliability by altering solubility upon activation, allowing for improved coating and developing properties.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If silsesquoxane-based polymer waveguides are used, then optical waveguide formation is achieved, but cracking and lifting defects occur under thermal stress
Solution Approach 1:
The patent uses a composite polymer system combining silsesquoxane polymer with flexibilizing agents (silicone oil, polyether, or carboxylic acid). This composite material approach allows the waveguide to maintain structural integrity while accommodating thermal expansion differences between the waveguide and substrate, preventing cracking and lifting under thermal stress.
Solution Approach 2:
The patent modifies the polymer composition parameters by incorporating specific flexibilizing additives in controlled amounts (0.1-10% by weight). This changes the physical and chemical properties of the polymer, specifically its flexibility and thermal response characteristics, enabling it to withstand thermal cycling without failure.
2Reliability
If polymer flexibility is improved by adding flexibilizing agents, then thermal cycling resistance is enhanced, but coating and developing properties may deteriorate
Solution Approach 1:
The patent carefully controls the type and concentration of flexibilizing agents to optimize both flexibility and processability. By selecting specific agents (silicone oil, polyether, carboxylic acid) and limiting their concentration to 0.1-10% by weight, the patent maintains adequate coating and developing properties while achieving thermal cycling resistance.
Solution Approach 2:
The patent applies different flexibilizing agents or combinations in specific formulations for core and cladding layers, allowing each layer to have optimized properties for its specific function while maintaining overall waveguide performance and manufacturability.
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 solution provides optical waveguides that withstand thermal cycling tests without cracking, delamination, or surface defects, maintaining optical integrity and reliability across diverse thermal conditions.
Implementation Method 1
an electron beam or optical radiation curable, organic soluble mixture comprising at least one oligomerized cyclobutarene made from a cyclobutarene monomer bridged by an oranopolysiloxane and at least one photosensitive agent in an amount sufficient to convert the mixture to a polymer insoluble in a development solvent upon exposing the mixture to electron beam or optical radiation
Data Source
Figure 1
AI summary
Provided are polymers comprising the condensation product of silicon-containing reactants. Also provided are compositions suitable for use in forming optical waveguides which include such polymers, as well as optical waveguides formed from such polymers. The polymers, compositions and optical waveguides have particular use in the formation of printed wiring boards having electrical and optical functionality.