Automated eutectic attachment is a leading technique for high-performance and high-capacity die attach applications. The needs of the current industry environment— with high-volume and high-placement accuracy (±5 microns)—clearly call for flexible automated equipment.
The most significant advantages of eutectic die attach are its great thermal solder
conductivity and its immediate fixing of bonds after die placement.
Eutectic bonding’s unique thermal conductivity makes it desirable over epoxy-silver bonding in power device or radio frequency amplifier applications. Concurrently, the processes of introducing a cover gas, solder wetting, and employing preform solder help to secure the bonds.
High-reliability eutectic bonds can be acheived through two heated system configurations: Steady Heater Stage (SHS) or Pulsed Heat Stage (PHS). The decision between the two techniques hinges on the desired process of die bonding and material requirements.
The Pulsed Heat Stage is preferred when AuSn solder is pre-placed on the die, the substrate, or sandwiched between the two. This way, the solder is only heated up specifically when the die and the substrate are in contact and bonding. In this process, Steady Heat Stage would have caused the AuSn to melt and change composition before the die is placed.
The Palomar Technologies Pulsed Heat Stage (PHS) is an intuitive method of void-free eutectic die attach. Designed to improve on CAMAX Heat Stage techniques, PHS features five crucial advancements:
- Controller
- Data storage
- Heater stage size
- Programmable cover lid
- Technical and mechanical support
Download the PHS data sheet and eBook: "Improved Eutectic Attach with PHS" to learn more.
Steady Heater Stage is still a viable eutectic process solution for cases when bonding an Au-backside metalized Si die and an Au-metalized substrate. The AuSi bond is formed between the two when a steady amount of heat is applied to the die and substrate. In addition, the technique of scrubbing, or moving the die quickly over the substrate repeatedly on its XY axis in a “scrubbing” motion, is used to strengthen the bond.
Automation for Increased Efficiency
Present-day automated die bonding equipment permit multichip eutectic die attach packages to be processed and assembled in a single pass with mechanized substrate and die handling. This means much more efficiency of an automatic die attach process when compared to a manual die attach process.
A manual process has a very low capacity and requires a highly skilled operator. Additionally, because of longer cycle times per placement inherent in manual processes, the capability to perform multiple placements in a single pass to the heated work area is quite limited.
The goal of automation is cost-effectiveness. Assembly automation has resulted in tremendous cost savings and renewed competitiveness.
Download the Automated Eutectic Die Attach eBook for a deeper, technical inspection of the following:
- Eutectic Bonding – How it Works
- Automation for Increased Efficiency
- Automation Requirements
- Meeting Accuracy and Throughput Demands
- Application Example
- Summary
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Jessica Sylvester
Marketing Communications
Palomar Technologies, Inc.