Acoustic Wave Module Support Structure for Larger Resonator Area
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Solution Overview
Problem
The challenge is to increase the area for functional elements in acoustic wave devices while maintaining sufficient rigidity and resistance to external pressure, as existing wafer level package structures face limitations in reducing the outer peripheral support layer's proportion without compromising structural integrity.
Innovation Solution
The proposed solution involves an acoustic wave device design with a piezoelectric substrate, an outer peripheral support layer, a cover portion, a protective layer, and an internal support layer, where protruding portions of the outer peripheral support layer and internal support layer overlap through-holes to distribute external stress, allowing for a reduced outer peripheral support layer area and an enlarged hollow space for functional elements.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If the dimension of the outer peripheral support layer in the width direction is increased, then the rigidity against external pressure is improved, but the area for disposing functional elements is reduced
Solution Approach 1:
The invention introduces a vertical dimension solution by forming protruding portions that extend upward from the outer peripheral support layer. These protrusions provide structural reinforcement against external pressure without increasing the horizontal footprint of the support layer, thereby maintaining the hollow space area for functional elements while improving rigidity through three-dimensional structural design.
Solution Approach 2:
The protruding portions are strategically positioned at specific locations on the outer peripheral support layer where structural reinforcement is most needed. This localized approach provides enhanced rigidity at critical stress points without uniformly increasing the support layer area, thus preserving maximum hollow space for functional element disposition.
2Area of stationary object
If the proportion of the outer peripheral support layer on the piezoelectric substrate is reduced, then the hollow space area is enlarged, but the rigidity against external pressure decreases
Solution Approach 1:
By transitioning from a two-dimensional planar support structure to a three-dimensional structure with vertical protrusions, the invention achieves enhanced rigidity with reduced material usage. The protruding portions provide structural strength in the vertical dimension, allowing the horizontal area of the outer peripheral support layer to be minimized while maintaining adequate rigidity.
Solution Approach 2:
The invention changes the geometric parameters of the support structure by introducing height as a new dimension through protruding portions. This parameter change allows the support layer to achieve higher rigidity-to-area ratio, enabling reduced proportion of the support layer while maintaining structural integrity.
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 configuration effectively increases the area for functional elements while maintaining the device's rigidity and resistance to external pressure, preventing deformation and ensuring reliable operation.
Implementation Method 1
an acoustic wave device having a general WLP structure has a configuration such that a plurality of functional elements are disposed on a piezoelectric substrate
Data Source
AI summary
An acoustic wave device includes a piezoelectric substrate, functional elements, an outer peripheral support layer, a cover portion, and a protective layer covering the cover portion. A hollow space is defined by the piezoelectric substrate, the outer peripheral support layer, and the cover portion, and the functional elements are disposed in the hollow space. The acoustic wave device further includes an under bump metal layer, a wiring pattern, and a through-electrode that connects these elements. In the protective layer, a through-hole to be filled with a conductor to electrically connect a solder ball and the under bump metal layer is provided. The outer peripheral support layer includes a protruding portion protruding to the hollow space. When the acoustic wave device is seen in plan view, at least a portion of the through-hole overlaps the hollow space, and an end portion of the protruding portion overlaps an inner region of the through-hole.