Why is flipchip called as controlled collapse chip connection ?

[Gayathri Jeyaram]

Hi,

Flipchip package is also called as controlled collapse chip connection. Why ?

 

[gag2000]

Hello,
Perhaps because small indium balls used to make electrical connection and mechanical strenght are melted "just as necessary" to connec the chip and the PCB (or another chip).
Then, the ball looks like if they had been collapsed.
Just a suggestion !