Antenna Substrate High-Dk Insulating Layer Thickness Reduction
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Solution Overview
Problem
Conventional antenna substrates using epoxy mold compounds or high dielectric constant prepregs face issues with thickness, yield, and reliability due to mold process problems and dielectric constant differences, leading to increased thickness and generation of harmful out-gas.
Innovation Solution
An antenna substrate structure featuring a conductive antenna pattern layer with a first and second insulating layer, where the second insulating layer has a higher dielectric constant and thickness, and is formed with materials like TiO2, Al2O3, or BaTiO3, to shift the resonant frequency and reduce thickness, while the first insulating layer is made of SiO2, effectively addressing the reliability and yield issues.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If a conventional epoxy mold compound is used to form a dielectric layer for resonance frequency, then the resonance frequency can be achieved, but the overall thickness of the antenna module becomes thick (300 μm or more)
Solution Approach 1:
The patent changes the dielectric constant parameter of the insulating layer from conventional values (epoxy mold compound with Dk≈4.0) to a high dielectric constant material (Dk≥10.0). This parameter change allows achieving the same resonance frequency with a significantly reduced thickness, resolving the contradiction between thickness reduction and resonance frequency maintenance.
Solution Approach 2:
The patent uses a composite insulating layer comprising a resin matrix and inorganic filler particles (such as barium titanate, lead zirconate titanate, or strontium titanate) to achieve high dielectric constant. This composite material approach enables both thin profile and reliable performance without the defects associated with conventional epoxy mold compounds.
2Quantity of substance
If a high dielectric constant prepreg is used during lamination process, then resonance frequency can be formed, but substrate warpage occurs due to dielectric constant difference
Solution Approach 1:
The patent changes the dielectric constant parameter to Dk≥10.0 while carefully controlling the thickness and material composition to minimize warpage. The high dielectric constant material is applied as a thin layer (10-50 μm) which reduces the overall impact on substrate flatness while still achieving resonance frequency formation.
Solution Approach 2:
The patent applies the high dielectric constant material locally only where needed for resonance frequency formation, rather than using it throughout the entire substrate. This localized application minimizes the dielectric constant difference across the substrate, reducing warpage while maintaining the desired resonance characteristics.
3Quantity of substance
If high dielectric constant prepreg is used in antenna substrate manufacturing, then resonance frequency is achieved, but static electricity and OUT-GAS are generated reducing yield
Solution Approach 1:
The patent uses inorganic filler particles (barium titanate, lead zirconate titanate, or strontium titanate) dispersed in a resin matrix to achieve high dielectric constant. These inorganic materials are stable during lamination and do not generate out-gas or static electricity issues, thereby improving manufacturing yield while maintaining thin profile.
Solution Approach 2:
The patent replaces expensive and problematic high dielectric constant prepreg materials with a more stable composite material system using inorganic fillers in resin. This substitution eliminates the out-gas and static electricity generation issues associated with conventional high-Dk prepregs, improving manufacturing 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
The proposed structure significantly reduces the antenna substrate thickness, enhances yield by avoiding mold process reliability issues, and lowers production costs by eliminating high dielectric constant prepregs, while maintaining performance comparable to conventional epoxy mold compounds.
Implementation Method 1
the second insulating layer has a higher dielectric constant and thickness than the first insulating layer
Data Source
AI summary
An antenna substrate according to the embodiment includes a substrate; an antenna pattern layer on the substrate; a first insulating layer including a resin and an inorganic filler on the substrate and the antenna pattern layer; and a second insulating layer including a resin and an inorganic filler on the first insulating layer, and wherein the second insulating layer has a higher dielectric constant and thickness than the first insulating layer.