Additively Manufactured EMI Shield for Semiconductor Packages
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Solution Overview
Problem
Current semiconductor packaging technologies face challenges with electromagnetic interference (EMI) shielding, thermal management, and thermal interface material (TIM) adhesion, particularly in multi-chip packages, where EMI shielding methods are inefficient, TIMs have high thermal resistance, and adhesion issues occur with silicon surfaces.
Innovation Solution
The use of high throughput additive manufacturing (HTAM) for creating substrate integrated posts, integrated heat spreaders, and highly conductive layers, along with additively manufactured EMI shield layers, to enhance thermomechanical performance, reduce thermal resistance, and improve adhesion without the need for traditional wafer-level backside metallization.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If discrete metal enclosures are used for EMI shielding, then electromagnetic interference protection is improved, but assembly time and package volume increase
Solution Approach 1:
The patent merges multiple discrete EMI shielding enclosures into a single integrated package-level shield structure. This consolidation reduces the number of separate assembly steps and components, thereby decreasing assembly time while maintaining comprehensive EMI protection across all electronic components within the package.
Solution Approach 2:
The package-level EMI shield serves as a universal protective structure that simultaneously shields multiple electronic components from electromagnetic interference. This multi-functional approach replaces the need for individual enclosures for each component, reducing both assembly complexity and overall package volume.
2Object-affected harmful factors
If sputtering or plating is used for package-level shielding, then EMI protection is improved, but equipment cost increases and deposition rate decreases
Solution Approach 1:
The patent replaces the traditional sputtering or plating processes with a mechanical deposition method. This substitution eliminates the need for expensive vacuum equipment and complex process controls while achieving comparable or superior shielding effectiveness with faster deposition rates and lower equipment costs.
Solution Approach 2:
The invention changes the fundamental parameters of the deposition process by using a mechanical approach instead of thermal or chemical methods. This parameter change enables higher deposition rates, reduced equipment cost, and improved adhesion while maintaining the desired EMI shielding performance.
3Temperature
If solder TIM is used for thermal management, then thermal conductivity is improved, but adhesion to silicon decreases
Solution Approach 1:
The patent introduces an intermediary layer between the solder TIM and the silicon die surface. This intermediary layer serves as a bridge that provides both the high thermal conductivity of solder and the strong adhesion to silicon, resolving the contradiction between thermal performance and bonding reliability.
Solution Approach 2:
The invention uses a composite material structure combining solder with adhesion-promoting materials. This composite approach maintains the excellent thermal conductivity of solder while incorporating components that enhance bonding to silicon surfaces, thereby achieving both high thermal performance and reliable adhesion.
4Reliability
If die backside metallization is used for TIM adhesion, then adhesion is improved, but manufacturing complexity increases
Solution Approach 1:
The patent extracts the metallization step from the wafer fabrication process and relocates it to the packaging stage. This extraction eliminates the need for complex backside metallization during semiconductor manufacturing, simplifying the fabrication process while still providing the necessary adhesion for TIM bonding at the package level.
Solution Approach 2:
The invention performs the metallization preparation as a preliminary action during package assembly rather than during wafer fabrication. This timing change allows for simpler processing conditions and reduces the overall manufacturing complexity while ensuring proper adhesion surfaces are available when TIM bonding is required.
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 approach enables cost-effective, efficient EMI shielding, improved thermal management, and enhanced adhesion of TIMs to silicon surfaces, addressing the limitations of existing technologies by simplifying the packaging process and reducing thermal resistance.
Implementation Method 1
a third layer comprising an additively manufactured layer disposed on the lid and electrically connecting the EMI shield and the lid
Implementation Method 2
an electromagnetic interference (EMI) shield disposed over a mold layer and beneath a lid
Data Source
AI summary
A device package and a method of forming the device package are described. The device package includes a substrate having a ground plane and dies disposed on the substrate. The dies are electrically coupled to the substrate with solder balls or bumps surrounded by an underfill layer. The device package has a mold layer disposed over and around the dies, the underfill layer, and the substrate. The device package further includes an additively manufactured electromagnetic interference (EMI) shield layer disposed on an outer surface of the mold layer. The additively manufactured EMI shield layer is electrically coupled to the ground plane of the substrate. The outer surface of the mold layer may include a topmost surface and one or more sidewalls that are covered with the additively manufactured EMI shield layer. The additively manufactured EMI shield may include a first and second additively manufactured EMI shield layers and an additively manufactured EMI shield frame.