Connect, no.123, March - April 2003, p.6
Ink jet printing technologies are used in a wide range of applications including home, office and industrial printing. Recently TWI carried out a Core Research Programme (CRP) project to investigate the feasibility of using aDrop-on-Demand printer to dispense pico-litre droplets of adhesives for electronics and photonics packaging.
Fig.1. The ink jet printing system used to dispense adhesives
Commercially available adhesives were successfully dispensed on substrates such as ITO coated glass, metals and silicon using a modified Xaarjet 126 printhead. The printing system consists of a PC for graphic design and control, animage configuration module, printhead, x-y tables, NC controller and monitor, as well as an ink supply unit to provide continuous supply to the printhead.
During the experiment, it was found that the jetting process was affected by certain variables such as jetting temperature, jetting pressure, surface preparation, substrate temperature and the properties of dispense materials. Withlow viscosity adhesives, the system can currently dispense droplets with 150 picolitre volume. When adhesives are printed over an area, a minimum-coating thickness of 2µm has been achieved with selected adhesives on selectedsubstrates.
Fig.2. An array of adhesive droplets jetted onto the silicon substrate
The ink jet printing technology is known to be a highly cost-effective, precise, and environmentally friendly method of micro-dispensing a wide variety of materials used in microelectronics and photonics packaging, includingadhesives, dielectrics, optical grade epoxies, particle-filled systems, solders and fluxes. The TWI printing system is capable of providing an in-situ process providing both picolitre volume control and high printing speeds for a rangeof applications.
For more information, please contact Sue Huang at TWI. E-mail sue.huang@twi.co.uk
