Conductive Paste EMI Shielding for System-in-Package
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Solution Overview
Problem
Conventional EMI shielding for system-in-package (SiP) technology is complex and expensive due to a two-step process involving through-mold laser trench drilling and physical vapor deposition sputtering, which is costly and has a low deposition rate.
Innovation Solution
A single-step conductive paste printing process is used for both internal and external EMI shielding, eliminating the need for expensive sputtering and simplifying the assembly process, while providing adequate shielding through a conductive paste with sufficient conductivity and adhesive properties.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a two-step process (through-mold laser trench drilling followed by sputtering) is used for EMI shielding, then effective EMI shielding is achieved, but the process becomes complex and expensive
Solution Approach 1:
The patent combines the internal EMI shielding (previously requiring laser trench drilling and conductive paste application) and external EMI shielding (previously requiring sputtering) into a single sputtering process step. This merging eliminates the need for separate laser drilling and paste dispensing operations, reducing process complexity while maintaining shielding effectiveness through a continuous metallic coating applied to both internal and external surfaces.
Solution Approach 2:
The sputtering process is made multi-functional by using it for both internal trench filling and external surface coating in a single operation. The same deposition equipment and material source serve dual purposes: filling internal shielding trenches and creating external shielding layers, thereby eliminating the need for separate specialized processes for each function.
2Reliability
If sputtering is used for external EMI shielding, then effective shielding is produced, but the deposition rate is low and equipment cost is high
Solution Approach 1:
By merging internal and external shielding into a single sputtering step, the patent eliminates the sequential nature of separate processes. The sputtering deposition occurs once for both functions simultaneously, effectively doubling the productivity compared to sequential processes while maintaining the quality and effectiveness of the shielding coating.
3Reliability
If a two-step process with laser trench drilling and conductive paste is used, then internal EMI shielding is achieved, but the overall process becomes more expensive and time-consuming
Solution Approach 1:
The patent merges the internal shielding formation (previously requiring laser drilling of trenches followed by paste application and curing) with external shielding deposition into a single sputtering process. This eliminates the sequential time consumption of drilling, paste dispensing, and curing steps, reducing total fabrication time while achieving equivalent or superior internal shielding through direct metallic deposition.
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 reduces fabrication costs and time by integrating internal and external EMI shielding in a single process, maintaining effective shielding despite higher resistivity, thus offering a more efficient and cost-effective solution for SiP technology.
Implementation Method 1
a single process for internal and external EMI shielding... the process applying using low cost and high throughput conductive paste printing technology
Implementation Method 2
Commonly a physical vapor deposition process by sputtering of copper is then used to produce an external EMI shielding for the entire SiP
Data Source
AI summary
Embodiments are generally directed to electromagnetic interference shielding for system-in-package technology. An embodiment of a system-in-package includes a substrate; chips and components attached to the substrate; dielectric molding over the chips and components; and an electromagnetic interference (EMI) shield. The EMI shield formed from a conductive paste, and the EMI shield provides a combined internal EMI shield between chips and components of the system in package and external EMI shield for the system-in-package.