A good die attach process is essential to ensure that the integrated circuit (IC) die is securely attached to its package, providing both mechanical stability and electrical connectivity. The process must be reliable, cost-effective, and capable of withstanding the thermal and mechanical stresses encountered during operation.

Three key considerations essential for a good die attach process are:

Die Attach Materials:

• Epoxies: Die attach epoxies include both non-conductive and conductive epoxy. Standard conductive epoxies are usually silver-filled. Epoxies are more commonly used for most of today’s application.
• Solder Paste: In some advanced packaging (such as flip-chip), solder paste or solder balls can be used. Solder provides better thermal and electrical conductivity.
• Underfill: For flip-chip packages, underfill material is often applied after the die is attached to enhance thermal and mechanical reliability.

Die Placement:

• Precision Die Placement: The die must be placed accurately on the package to ensure proper alignment and to avoid issues with electrical or thermal performance. This is typically done using a pick-and-place machine with high precision.
• Bonding Pressure: Applying the correct pressure during placement is important for achieving a uniform bond and avoiding excessive stress on the die or package.

Curing:

• Curing (for Epoxy): If using an adhesive, the die attach adhesive must be cured, typically by heating in an oven or curing chamber. The exact temperature and time depend on the adhesive material and formulation.
• Solder Reflow: For solder-based die attach, the die and substrate are heated to the reflow temperature of the solder, ensuring proper melting and bonding between the die and the package.
• Thermal Profiles: The process requires a carefully controlled thermal profile to avoid thermal shock and to ensure uniform heat distribution.

As can be seen, die attached materials are closely related to the other two factors. DELO adhesive offers a range of DA epoxies that meets applications with specific requirements relating to:

• High die bonding strength.
• Fast curing time for high UPH.
• Low temperature curing that does not heat stress other components.
• High reliability.

Some typical products are IC343, DA375, DA772, DA254, DA255 etc.