Pan Pacific Symposium Conference Proceedings


Authors: H. Quinones, A. Babiarz, E. Fiske, L. Fang
Company: Asymtek Headquarters
Date Published: 2/10/2004   Conference: Pan Pacific Symposium

Abstract: Fluid dispensing in the microelectronic packaging has traditionally performed by way of needle dispensing: pressure-time, displacement and augur pumps are frequently used. The jetting technology for low viscosity and highly incompressible fluids has been around for many years. Several materials used today for different applications in the electronics include high viscosity fluids and somewhat compressible.

These fluid properties pose enormous difficulties for traditional non-contact jetting processes. Volumetric accuracy in the dispensing cannot be compromised with introductions of new processes i.e., jetting. Advances and improvements in technology continuously drive to smaller scale packages. This has allowed for more efficient use of resources (a silicon chip that once held hundreds of transistors now holds millions) and more convenient and consumer friendly products (palm sized computers compared to warehouse sized computers forty years ago).

However, as advances lead to decreases in the scale of components, similar advances must be made in the production process in order to assemble these components. As components decrease in size, so does the gap between the leads. It is therefore necessary for the size of the adhesive dot to decrease to the same degree as the components decrease. Anticipating the continuing trend in component scale reduction, however, predicts that dots of less than 150 micrometers in diameter range will be required.

The underfilling of 2D and 3D-packages with small gaps, yet large geometries as well as the underfilling of small die present another challenge to the consistency and accuracy of dispensing processes. The majority of encapsulates fluids, presently used are filled with abrasive materials.

The difficulty of jetting abrasive materials and proposed solutions are addressed in this paper. High fluid flow rate is essential for manufacturing products. We proposed a method to accomplish fluid flow rates of more than 100 mg/s. Optoelectronics is another technology where non-contact jetting is desired. We propose design and process for jetting various materials including, UV cure and moisture cure fluids, where jetting outperforms traditional needle dispensing, both in quality as well as in throughput.

Key words: ball-needle, jetting, non-contact, high viscosity, underfill, pre-applied.

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