New microelectronics adhesive for ultra-fine structures

DELO has created a new adhesive that can be employed to create ultra-fine structures within seconds. DELO DUALBOND EG4797 opens new possibilities in heterogeneous integration and optical packaging applications. The material can realise unlimited freeform structures and razor-thin optical barriers, answering the ongoing trend towards miniaturisation.

The halogen and solvent-free acrylate permits extremely fine microstructure designs – so-called micro dams – in semiconductor packaging and on PCBs. With it, bondlines with widths of less than 100µm in an aspect ratio of five or more can be dispensed. Previously, attaining line widths of even 200µm was considered a challenge. This new micro dam solution was developed in close partnership with NSW Automation, a systems manufacturer which creates high-precision microdispensing technologies for the semiconductor industry.

A special feature of the product is its high thixotropic index of 6.6. This allows high dispensing speeds of 15mm/s or more while creating a stable microstructure layer by layer on straight and curved surfaces. Fine bond lines are dispensed using conical needles with a diameter of 100µm.

After dispensing, the micro dam is cured in one step. The process can be set up flexibly while remaining energy efficient. Curing can be carried out in ten seconds using only UV light, in five minutes using only heat at +120C, or via a dual-curing process using both UV light and heat.

The product proves to be an extremely good adhesive in typical testing for compliance with microelectronics and semiconductor industry standards such as JEDEC MSL.

This new product comes in response to increasing demand for high-performance electronic components and the ongoing trend towards miniaturisation, with more and more powerful functioning parts needing to be accommodated on PCBs.

Microstructures, for example, can serve as flow stops and reduce keep-out zones (KoZ). These areas within a PCB layout limit the flow of underfill adhesives used to reinforce solder contacts, protecting surrounding components. In optical packaging, such as in LED module manufacturing, micro dams act as optical barriers.

Due to ultra-fine micro dams and their various process options, freeform structures can take on an almost limitless number of designs, and new, unprecedented package layouts can be attained. At the same time, the amount of space needed can be lowered to a minimum.

DELO will be on display at the IMAPS Symposium from September 30 to October 3, 2024, and at IEMT from October 16 to 18, 2024.