Reza Kazemi | Komori America Corporation: Is silver ion migration compromising the reliability of your fine-pitch electronics?

How can you print high-viscosity pastes with 5-micron resolution?

Gravure offset printing is a unique two-step process that combines the principles of both gravure and offset printing for high-precision applications. First, a high-viscosity paste, such as solder or copper, is applied to a rigid, engraved plate (gravure). A doctor blade then wipes the surface, ensuring the paste remains only within the micro-scale engraved patterns. This precise filling of the plate is the first key to achieving high-resolution features.

The critical innovation lies in the second step: the offset transfer. Instead of printing directly from the plate to the substrate, the patterned paste is first picked up by a soft silicone blanket. This indirect transfer is crucial because the blanket absorbs excess solvents from the paste, which significantly reduces bleeding and smearing. This solvent absorption and the blanket's conformability prevent mechanical deformation of the fine features, allowing for exceptionally clean and stable pattern transfer.

This combination of a rigid, precise plate and a soft, absorbent blanket gives gravure offset its distinct advantage. It allows the use of highly functional, high-viscosity pastes—which are often difficult to jet or dispense finely—while still achieving resolutions down to 5 microns with a positional accuracy of ±5 microns. This capability makes it ideal for applications requiring fine, narrow-gap patterns like solder deposition and interconnects, where other methods like screen printing struggle.

In this short video, you can learn:
* The fundamental two-step mechanism of gravure offset printing.
* Why the silicone blanket is the key to achieving high resolution and accuracy.
* How this process uniquely enables fine-feature printing with high-viscosity pastes.

📋 **Clip Abstract** This clip details the gravure offset printing process, a high-precision additive manufacturing technique. It explains how the indirect transfer via a silicone blanket enables the printing of fine features down to 5 microns using high-viscosity pastes.
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Are traditional metal masks holding back your microLED display manufacturing?

As electronic components become denser, particularly in advanced packaging and microLED displays, the joints and interconnects must shrink dramatically. Traditional solder deposition methods using metal masks face fundamental physical limitations. The "area ratio" rule dictates the smallest opening a mask can have relative to its thickness to ensure proper paste release. For the ultra-fine pitches required by microLEDs, these masks struggle with incomplete paste filling and inconsistent deposition, creating a major bottleneck for high-yield manufacturing.

Gravure offset printing provides a powerful alternative by completely eliminating the need for metal masks. The process allows for the precise deposition of extremely small solder dots with excellent control over volume and thickness. By leveraging advanced, commercially available materials like Type 9 and Type 10 solder pastes, which contain particles as small as one micrometer, gravure offset can produce solder bumps in the 8 to 24-micrometer range, perfectly suited for microLED bonding.

The viability of this technique is demonstrated with a functional microLED sample. After printing 18-micrometer solder bumps using Type 10 paste, microLED dies were transferred and subjected to a reflow process. The resulting solder bumps maintained their shape and integrity, leading to a fully functional, illuminated microLED array. This successful proof-of-concept highlights the technology's capability to enable the next generation of high-resolution microLED displays through a scalable, high-precision additive process.

In this short video, you can learn:
* The limitations of traditional metal masks for fine-pitch solder printing.
* How gravure offset enables the printing of micro-solder bumps (8-24 µm) using Type 10 paste.
* A real-world example of a functional microLED device built using this technique.

📋 **Clip Abstract** This segment explores the application of gravure offset printing for creating ultra-fine solder bumps for microLEDs. It demonstrates how the technology overcomes the limitations of metal masks to produce functional devices with 18-micron features.
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