SAW Filter Module Packaging With Protected Cavity Formation

Solution Overview

Problem

Conventional surface acoustic wave filter module packaging using wafer level injection molding is costly and prone to chip deformation and cracking due to high injection pressure, leading to structural instability.

Innovation Solution

A packaging structure and method involving a substrate with surface acoustic wave filter and non-filter chips, fixed by convex structures, a dry film layer, and a plastic sealing layer, utilizing vacuum airbag lamination and fracture areas to form a cavity without breaking convex structures, reducing reliance on injection molding.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If wafer level injection molding packaging is used, then packaging efficiency is improved, but injection pressure causes chip deformation and cracking

Engineering Contradiction:

Improvepackaging efficiencyVSAvoidchip structural integrity

Core Design Contradiction:

ProductivityVSReliability

Solution Approach 1:

The patent segments the packaging process into two distinct stages: first forming cavities at the wafer level without high pressure, then performing injection molding at the module level. This segmentation allows each stage to use optimized pressure parameters, preventing convex structure damage while maintaining packaging efficiency.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The patent performs preliminary cavity formation at the wafer level before final injection molding packaging. By pre-forming cavities using low-pressure methods (such as compression molding or vacuum forming), the convex structures are protected from high injection pressure, and subsequent injection molding only needs to fill remaining spaces, maintaining both reliability and efficiency.

Inventive Principle:

Principle #10Preliminary action

2Reliability

If compression molding is used, then injection pressure is reduced, but cavities form on the plastic sealing layer surface

Engineering Contradiction:

Improveconvex structure integrityVSAvoidplastic sealing layer surface quality

Core Design Contradiction:

ReliabilityVSManufacturing precision

Solution Approach 1:

The patent performs preliminary cavity formation at the wafer level before final injection molding packaging. By pre-forming cavities using low-pressure methods (such as compression molding or vacuum forming), the convex structures are protected from high injection pressure, and subsequent injection molding only needs to fill remaining spaces, maintaining both reliability and efficiency.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The patent applies different packaging approaches to different regions: wafer-level cavity formation uses low-pressure methods to protect convex structures, while module-level injection molding uses high pressure only for filling non-critical areas. This localized quality approach ensures surface quality where needed while protecting critical structures elsewhere.

Inventive Principle:

Principle #3Local quality

3Manufacturing precision

If high injection pressure is applied, then packaging completeness is improved, but convex structures deform and crack

Engineering Contradiction:

Improvepackaging completenessVSAvoidconvex structure strength

Core Design Contradiction:

Manufacturing precisionVSStrength

Solution Approach 1:

The patent segments the packaging process into two distinct stages: first forming cavities at the wafer level without high pressure, then performing injection molding at the module level. This segmentation allows each stage to use optimized pressure parameters, preventing convex structure damage while maintaining packaging efficiency.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The patent performs preliminary cavity formation at the wafer level before final injection molding packaging. By pre-forming cavities using low-pressure methods (such as compression molding or vacuum forming), the convex structures are protected from high injection pressure, and subsequent injection molding only needs to fill remaining spaces, maintaining both reliability and efficiency.

Inventive Principle:

Principle #10Preliminary action

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

Ensures reliable formation of a cavity between the chip and substrate, preventing convex structure damage, thereby enhancing reliability and reducing costs compared to traditional methods.

Implementation Method 1

The dry film layer attaches and covers the surface acoustic wave filter chip and the non-filter chip by vacuum airbag lamination

Methodology Applied

Scientific EffectVacuum lamination: Vacuum

Data Source

PatentUS20250274102A1Surface Acoustic Wave Filter Module Packaging Structure And Packaging Method Thereof

Publication Date: 2025.08.28 AAC ACOUSTIC TECH (SHENZHEN) CO LTD

AI summary

The present invention provides a surface acoustic wave filter module packaging structure and packaging method thereof. Packaging structure includes a substrate, a surface acoustic wave filter chip, a non-filter chip, a dry film layer, and a plastic sealing layer. Filter chip is fixed to substrate by first convex structures, a cavity is formed between filter chip and substrate. Non-filter chip is fixed to substrate by second convex structures. Dry film layer includes a fracture area surrounding non-filter chip, plastic sealing layer is filled between substrate and non-filter chip through fracture area. The packaging structure and method thereof of the present invention can ensure that a cavity can be formed between the bottom of surface acoustic wave filter chip and substrate, convex structures are not easily broken, avoiding the use of injection molding processes based on wafer level packaging filters, reducing costs and damage to chips during reliability testing.