John Lau | Swansea University: Could your screen printing emulsion parameters be the hidden cause of cracked chips during silver sintering?
00:16:03.468 - 00:17:25.008
Other snippets from this talk
Summary of the clip:
Could your screen printing emulsion parameters be the hidden cause of cracked chips during silver sintering?
Stencil edge effects, commonly known as "dog ears" in SMT processes, present a major reliability risk in advanced packaging. When emulsion build-up is too high relative to a fine, unsupported mesh, the squeegee scoops up excessive ink from the center. This leaves thick, raised deposits at the printed pattern's boundaries.
In applications like thermal chip bonding or silver sintering, these raised edge profiles act as severe localized stress points. When a silicon die or MicroLED is pressed onto a pattern with dog ears, the non-uniform mechanical pressure can easily crack the fragile chip.
To solve this issue, engineers should let the physical mesh do most of the volumetric metering. Combining a lower emulsion thickness with a coarser mesh produces a flat, uniform block print rather than a high-relief profile with harmful edge structures.
In this short video, you can learn:
* The mechanical root cause of "dog ear" edge profiles in screen printing
* Why non-uniform edge build-up leads to mechanical chip cracking during die attachment
* Practical design changes to achieve flat, uniform deposition using mesh-dominant metering
📋 **Clip Abstract** This clip highlights the danger of stencil edge effects ("dog ears") when printing conductive pastes for advanced packaging. Learn how over-engineered emulsion heights can inadvertently cause mechanical die failure during subsequent silver sintering and bonding steps.
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#SilverSintering, #ScreenPrintingEmulsion, #DogEarEffect, #DieAttach, #AdvancedPackaging, #PrintedElectronics
This is a highlight of the presentation:
Challenges and Opportunities in High‑Resolution Screen Printing
Future of Electronics RESHAPED USA 2026
10-11 June 2026
Computer History Museum, Mountain View, California, USA
Organised By:
TechBlick
More Highlights from the same talk.
00:04:19.760 - 00:06:16.020
Why does your ultra-precise screen printing layout distort when printing multi-material stacks?
Why does your ultra-precise screen printing layout distort when printing multi-material stacks?
Screen printing for high-accuracy applications requires strict control over the snap-off distance. A common rule of thumb is setting the snap-off to 1/300th of the internal frame diameter to minimize screen deformation. When you deform the mesh during the squeegee stroke, physical elongation of the mesh inevitably introduces layout distortion.
This distortion is highly sensitive to the mechanical settings of each individual run. If you are printing multi-material layers using the same frame size but under different snap-off settings, the variation in mesh elongation will prevent precise layer-to-layer registration.
To mitigate this, engineers must find a compromise. Running an excessively small snap-off causes ink bleeding and edge defects, while setting it too high causes extreme distortion or permanent plastic deformation of high-tension stainless steel meshes.
In this short video, you can learn:
* The 1/300th rule of thumb for snap-off optimization in precision printing
* How varying snap-off settings disrupt layer registration in multi-material stacks
* The catastrophic failure modes of over-tensioning high-end stainless steel meshes
📋 **Clip Abstract** This clip breaks down the mechanical kinematics of screen printing, focusing on how snap-off distance affects layout registration. Learn why incorrect mesh tension and snap-off parameters lead to irreversible plastic deformation and registration mismatches in multi-layer processes.
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#ScreenPrinting, #SnapOffDistance, #LayerRegistration, #MeshDeformation, #PrintedElectronics, #AdditiveElectronics
00:06:44.852 - 00:09:38.132
Stainless steel, polyester, or V-Screen: which mesh material prevents device failure in advanced packaging?
Stainless steel, polyester, or V-Screen: which mesh material prevents device failure in advanced packaging?
Selecting the correct mesh chemistry and structure is critical for advanced microelectronics fabrication. Stainless steel meshes offer unmatched dimensional precision, making them ideal for ultra-fine line printing down to 20 microns. However, metallic meshes can react chemically with active materials, such as silver chloride used in biosensors, leading to accelerated screen corrosion.
Polyester meshes present a more forgiving, low-cost alternative with excellent chemical resistance and long lifetimes, but they lack the mechanical wear resistance needed for abrasive materials like ceramic pastes. For high-resolution production, the practical printing limit for standard polyester is typically capped around 100 to 125 microns.
High-performance hybrid polymers, like V-Screen, attempt to bridge this gap. They deliver near-stainless-steel accuracy with much higher mechanical forgiveness, allowing for 50-micron features in production environments without the high structural risk of fragile, high-tension steel.
In this short video, you can learn:
* Chemical compatibility risks of using stainless steel meshes with active pastes
* The trade-offs in resolution, lifetime, and cost between polymer and metal meshes
* V-Screen hybrid polymer technology as a robust solution for sub-50 micron production
📋 **Clip Abstract** John Lau analyzes the material properties and trade-offs of stainless steel, polyester, and V-Screen meshes for high-end electronics. Discover how to align your choice of mesh with both paste chemistry and feature size to optimize yield and durability.
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#ScreenPrintingMesh, #VScreen, #FineLinePrinting, #AdvancedPackaging, #PrintedElectronics, #MicroelectronicsFabrication