Underfill is used in a wide variety of packages and board level assemblies. Flip chip in package, direct chip attach on boards, stacked die packages, and various BGA assemblies are places where underfill is being used in production today. The "part" to be underfilled can be either a die or the BGA substrate. While these packages often use different materials and require different production techniques, the underfill process is similar for both.
The proliferation of flip chip technology in digital cameras, cell phones, disk drives, medical devices such as pacemakers, defibrillators and hearing aids, has created a large demand for underfilling small die in the range of 1 mm square to 5 mm square. Whether the die are directly attached to flex, circuit boards, or some organic interposer, the area around the die available for dispensing underfill materials is getting smaller. This creates an enormous challenge for needle dispensing, but is ideal for non-contact jetting. Some underfill applications may still require traditional needle dispensing, such as with the DP Series Linear Pump. Contact Asymtek to find out what fits your application the best.
Successful production requires a flawless underfill process. With Mass Flow Calibration (MFC), Asymtek's dispensing systems automatically manage the critical processes related to underfilling: substrate heating, die finding, underfill volume control, dispense pattern and part handling. Closed-loop control of these processes minimizes operator intervention and optimizes the dispensing programs for highest throughput. All these processes are programmable in Fluidmove® for Windows® XP (FmXP) software.
Videos
- Underfill Jetting (.wmv 2.3 MB)
- Underfill DJ-9000 (.wmv 2.7 MB)
- Jetting - Jet UF in 350um Gap (.wmv 1 MB)
Related Articles & Papers
- Jet Dispensing - The Underfill Solution (PDF 336 KB)
- Read the Latest on Underfill Techniques, by Asymtek's Al Lewis (PDF 238 KB)
- Review of CSP and Flip Chip Underfill Processes (PDF 101 KB)
- Advances in Fast Underfill of Flip Chips (PDF 200 KB)
- Underfill Processes for Large-Small Flip Chip (PDF 176 KB)
- Jetting Pre-Applied Solder Ball Reinforcement with the DispenseJet® DJ-9000
