---
title: Eutectic Process Critical Control Parameters
description: Eutectic Die Attach requires critical control parameters including incremental thermal energy
---

[PTI Blog ](https://www.palomartechnologies.com/blog)

# [Eutectic Process Critical Control Parameters](https://www.palomartechnologies.com/blog/bid/20273/Eutectic-Process-Critical-Control-Parameters)

 Written by [Palomar Technologies MarCom Team](https://www.palomartechnologies.com/blog/author/palomar-technologies-marcom-team) | Tue, Aug 04, 2009 @ 00:08 AM

If making an investment in an [automated eutectic bonding system](http://palomartechnologies.com/SystemsSolutions/AutomatedComponentPlacementSystems/Model6500.aspx), getting the right partners and the right process (the first time) will prove tremendously cost-effective in the short and long run. Control is imperative! 

[Contract manufacturers](http://palomartechnologies.com/MicroElectronics.aspx) doing eutectic die attach applications usually specify process conditions, often gained from in-house experience, such as how much solder reflow is desirable to achieve sufficient mechanical bond strength to prevent voids between die and substrate. I should note that every application has its own specific set of requirements, with some machine parameters more critical than others - ultimately all need to be in proper porportion to obtain desired results.

*Critical control parameters *include 1) head force, 2) background temperature and incremented thermal energy, 3) soldering time, and 4) cover gas flow.

**Head Force**: Immediately after placing die on the substrate, the bond head pushes down on the die with a specified force. The amount of force applied must be sufficient to stimulate solder reflow and hold the die in place during reflow. Too much force can damage a component (by introducing "micro-cracks" that may affect electrical performance, for example). Small stress-sensitive die ranging up to 20 mils can take a fair amount of head force of typically up to 50 grams. Larger die generally require head forces of 100 grams or more.

**Background Temperature and Incremental Thermal Energy**: The substrate is heated to a background temperature, which is boosted during bonding till reflow occurs. The background temperature determines the amount of incremental thermal energy needed to initiate solder reflow - it indirectly controls soldering time.  

**Soldering Time**: The time span of head force and incremental thermal energy largely determines the extent of solder reflow and also impacts throughput time. Actual soldering time varies from a few seconds to 10-12 seconds depending on die size. 

**Cover Gas**: The flow of cover gas affects the rate at which the solder reflows and determines the quality of the intermetallic bond. 

[View full post](https://www.palomartechnologies.com/blog/bid/20273/Eutectic-Process-Critical-Control-Parameters)

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