Table of Contents
Assignment background
In the semiconductor manufacturing process, die attach (bonding of semiconductor chips to substrates) requires applying conductive paste to a small area.Extremely accurate and consistent applicationYou are required to do.
Conventional equipment and processes are prone to the following problems, which have become major issues at production sites:
- Variation in application accuracy due to difficulty in controlling minute amounts
Conductive paste requires minute amounts of discharge, on the order of a few nanoliters to a few tens of nanoliters, but the reproducibility of typical air-driven dispensers is insufficient.Variation in ejection volume and dot diameterThis was occurring. - Dripping and stringiness cause product defects and reduced yield
The viscosity characteristics of the paste and the response of the device do not match, and after the discharge is completeLiquid drips or strings from the nozzle tipThis can leave excess paste on the workpiece, which can lead to short circuits and reduced reliability. - Expensive paste material loss and increased costs
Conductive paste is expensive, with many costing several thousand yen per gram. If there is a large amount of material loss (dead volume),Risk of declining cost efficiencyalso occurs. - Contact-type dispensing puts stress on the workpiece and risks of foreign matter contamination
Conventional contact nozzles have issues with the reproducibility of application positions.The workpiece may be damaged or contaminated by contact with the nozzle.Such risks were also apparent.
Benefits
To address these issues, the electromagnetically controlled non-contact dispenser “NOVADOT” was introduced in this process. Its highly accurate dispensing control and non-contact structure have resulted in the following improvements:
- High-speed response × Non-contact × Stable minute amount dispensing
The electromagnetic drive system enables high-speed ON/OFF switching.Uniform dot formation even with a minute amount of ink, just a few nanoliters per shotThis reduces variations in conductive performance and improves reliability. - Sharp application results without dripping or stringing
High-response valve and optimized discharge waveformNo dripping or stringingThis resulted in a stable application of 100%. There was no unnecessary residue of the liquid on the product, and clean, highly reproducible application quality was achieved. - Minimizing material waste and reducing operational costs
A structure with little dead volume and no excess liquidThis significantly reduces material loss, which has a significant economic impact, especially in processes that handle expensive silver paste, and is expected to quickly recoup the cost of implementation. - Contactless method protects products and improves maintainability
The nozzle does not come into contact with the workpiece,No wear or physical damage occurs, and the risk of contamination is greatly reducedIn addition, nozzle clogging is less likely to occur, which reduces the frequency of equipment maintenance and replacement, and also reduces the workload.
Application process video also available
Introduced products
High-speed electromagnetic control non-contact dispenser NOVADOT
- Non-contact application of minute amounts in nanoliter units
High-speed electromagnetically controlled opening and closing valvesDischarges minute dots of a few nL per shotStably achieves this. Ideal for high-precision dispensing of conductive materials. - Maintains high reproducibility even with high viscosity paste
With a new high-torque engine and optimized discharge waveform control,Even with high-viscosity materials such as silver paste, there is little variation in line diameter and dot diameter, enabling uniform application.. - High-speed response design that eliminates dripping and stringiness
Excellent liquid drainage performance at the end of application,Less buildup, dripping, and residue at the end of applicationPrevents unwanted liquid from appearing on the product, ensuring a clear application surface. - Non-contact type protects products and extends equipment life
The nozzle does not come into contact with the workpiece,Safely adaptable to delicate semiconductor chips and high-precision FPCsThere is little risk of contact damage or nozzle wear.
