Here is the abstract you requested from the DPC_2009_FlipChip technical program page. This is the original abstract submitted by the author. Any changes to the technical content of the final manuscript published by IMAPS or the presentation that is given during the event is done by the author, not IMAPS.
|Managing the Underfill Process for Large Die|
|Keywords: Underfill, Flip Chip, Jetting|
|In the world of microelectronic assembly most process developments are aimed at making smaller components, to fit more functions into every decreasing sized portable device. This presentation will look at large device underfill, where the silicon is over 15mm square and the amount of underfill required is on the order of 30 to 50 mg. The manufacturing process for these large die are pushing throughput requirements to much higher levels than seen on production lines today and this brings new challenges to dispensing underfill. When such large devices are produced at rates over 4000 uph the dispensing tools have to move a lot of material. The sheer volume of material can have a cooling effect on the valve or jet. Large changes in the flow of underfill materials through the valve can impact the accuracy of shot size by cooling down the valve or jet. Therefore volume accuracy is impacted and this can impact material keep out zones. Constant temperature of the jet able fluids, results in greater repeatability of shot size, aid flow in the jet and under the die, and improve fluid break off. Most simple examples of temperature controls attempts to control needle tip temperatures, however it has been found that this can be difficult to control temperature reliably at the tip when moving a large volume of fluid. Therefore it has been found necessary to have good shot weight reproducibility that a total integrated heating system is required that controls fluid temperature, starting up stream of the dispensing tool and accurately controls fluid temperatures all the way to the dispensing tip. This extended abstract will show results with fluid and with out total controlled heating of all stages of the dispensing tool and the manufacturing cycle. The results will demonstrate the importance of applying heat correctly to the tool and its impact on throughput at high speed of large devices.|
|Steve Adamson, Market Manager