Integrated RF Filter Die for Wider Passband and Lower Loss
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Solution Overview
Problem
RF front-end chips face challenges in optimizing pass-band width and reducing size while maintaining high out-of-band rejection, as traditional electrical connections between resonance devices and passive devices occupy more space and increase manufacturing costs.
Innovation Solution
Integrating resonance devices, such as SAW or BAW devices, and passive devices, like IPDs, within a single die, reducing the need for electrical connections and minimizing chip space, while forming resonance devices on preprocessing layers and connecting them with passive devices through bonding processes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If resonance devices and passive devices are electrically connected in separate dies, then electrical connection is achieved, but chip space increases and manufacturing cost increases
Solution Approach 1:
The patent merges the resonance device and passive device into a single integrated structure where the resonance device is formed directly on the same die as the passive device. This eliminates the need for separate dies and external electrical connections, thereby reducing chip space while maintaining reliable electrical connection through direct integration.
Solution Approach 2:
The die is designed to serve multiple functions simultaneously: it hosts both the passive device (such as IPD) and the resonance device (SAW or BAW). This multi-functionality approach allows a single die to perform both filtering and resonating functions, reducing the overall chip space required compared to using separate dedicated dies for each function.
2Reliability
If resonance devices and passive devices are electrically connected in separate dies, then electrical connection is achieved, but manufacturing cost increases
Solution Approach 1:
By combining the resonance device and passive device fabrication into a single manufacturing process on one die, the patent eliminates the need for separate die fabrication, bonding, and wire bonding processes. This integration reduces manufacturing steps, lowers production complexity, and decreases overall manufacturing cost while ensuring reliable electrical connection.
Solution Approach 2:
The manufacturing process is segmented into distinct stages: forming the passive device on the die, then forming the resonance device preprocessing layer on the same die, and finally completing the resonance device. This segmented approach allows for optimized manufacturing at each stage while maintaining integration benefits, reducing overall manufacturing cost compared to processing separate dies.
3Reliability
If filters use SAW or BAW resonators, then high Q value is achieved, but pass-band width is limited
Solution Approach 1:
The patent employs a composite structure combining piezoelectric materials (for high Q value resonance) with carefully designed electrode configurations and preprocessing layers. This composite approach allows the resonance device to maintain high Q value characteristics while the integrated design with passive devices enables broader pass-band width by optimizing the overall filter response.
Solution Approach 2:
The patent uses dynamic electrode structures and configurable resonance device designs that can be adjusted to optimize performance. By making the electrode patterns and resonance device parameters adaptable, the filter can achieve both high Q value operation and broader pass-band width depending on the specific application requirements.
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 integration optimizes pass-band width, enhances out-of-band rejection, and reduces electrical transmission losses, thereby improving filter performance and reducing chip size and manufacturing costs.
Implementation Method 1
forming a first active layer of the at least one first resonance device based on the active preprocessing layer, and forming a first reflection layer of the at least one first resonance device based on the reflection preprocessing layer to reflect acoustic waves generated by the first active layer
Data Source
AI summary
A formation method of a filter device includes: forming a first layer by providing a first substrate and forming a resonance device preprocessing layer with a first side and a second side opposite to the first side, wherein the first substrate is located on the first side; forming a second layer by providing a second substrate and forming a first passive device with a third side and a fourth side opposite to the third side, wherein the second substrate is located on the third side; connecting the first layer located on the fourth side and the second layer located on the second side; removing the first substrate; and forming at least one first resonance device based on the resonance device preprocessing layer. The resonance device and the passive device are integrated in one die to form a filter device, which requires less space in an RF front-end chip.