Fluidic Die Conductive Paths for ESD Dissipation
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Solution Overview
Problem
Existing fluid ejection devices face issues with electrostatic discharge (ESD) strikes due to high electrical resistivity of epoxy molding compounds, leading to corrosion and cascading resistor failures, which previous solutions like shielding and circuit distance modification are costly and inefficient.
Innovation Solution
Implementing polymer-based conductive paths, such as conductive adhesives or polymers, to dissipate ESD strikes away from sensitive components in fluidic dies, using methods like stencil printing or photolithography, ensuring strong adhesion and adjustable resistivity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If epoxy molding compound is used for encapsulation, then manufacturing cost is reduced and encapsulation is achieved, but electrical resistivity is high which blocks ESD dissipation pathways
Solution Approach 1:
A conductive adhesive layer is introduced as an intermediary between the silicon sliver and the epoxy molding compound. This adhesive layer has lower electrical resistivity than the epoxy, creating an effective ESD dissipation pathway while allowing the epoxy to maintain its encapsulation function. The conductive adhesive mediates between the conflicting requirements of encapsulation (epoxy) and ESD protection (conductive path).
Solution Approach 2:
The encapsulation structure uses a composite material system consisting of the epoxy molding compound combined with a conductive adhesive layer. This composite approach allows the system to simultaneously achieve the encapsulation benefits of epoxy and the ESD dissipation properties of conductive materials, resolving the contradiction between manufacturing ease and reliability.
2Reliability
If shielding layers or increased circuit distance are used to protect against ESD, then ESD protection is improved, but device complexity and manufacturing cost increase
Solution Approach 1:
The invention extracts the ESD protection function from complex structural modifications (shielding layers, increased circuit distance) and implements it through a simple conductive adhesive layer. This removes the need for additional shielding components and complex circuit layout modifications, reducing device complexity while maintaining ESD protection.
Solution Approach 2:
Instead of changing structural parameters (adding shielding layers, increasing distances), the invention changes the material parameter (electrical resistivity) of the adhesive layer. By selecting an adhesive with appropriate conductive properties, ESD protection is achieved through material selection rather than structural complexity.
3Reliability
If conductive adhesive is applied to form conductive paths, then ESD dissipation is improved, but adhesion strength and manufacturing precision must be maintained
Solution Approach 1:
The conductive adhesive is applied locally only where ESD dissipation is needed - specifically between the silicon sliver and the epoxy molding compound. This localized application maintains manufacturing precision by limiting the adhesive application to specific areas rather than requiring uniform coverage across the entire device, reducing manufacturing complexity while achieving ESD protection.
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
The polymer-based conductive paths effectively prevent ESD-induced damage by providing a conductive pathway, maintaining device performance and reducing costs without degrading other functionalities.
Implementation Method 1
polymer based conductive paths for fluidic dies to dissipate electrostatic discharges (ESD) away from the electrically sensitive components of the fluidic die
Data Source
AI summary
In example implementations, a fluidic die is provided. The fluidic die includes a silicon sliver with a plurality of nozzles to eject a printing fluid. A conductive path is deposited along a length of the silicon sliver on opposite sides of the silicon sliver. The conductive path and a portion of the silicon sliver are encapsulated by an epoxy molding compound.