flipping the chip

[Martin]

I´m a stranger to this field, so please elaborate or name a reference:

there are lots o´ books out there on flip-chip technology,
but how is flipping the chip actually achieved?

Picture the following:
the chips/dice are resting face up on the adhesive thin film/tape
(the wafer is mounted on such for dicing) and are picked by a vacuum tweezer,

then what?
- Is there a second vacuum tweezer touching on the back side
of the chip while still beeing held by the first tweezer?
- Is the first tweezer equipped with a rotating head for spinning the chip 180°
and releasing it face down in order to pick it up again, only now touching
the back side?

What´s the actual scheme?

Thank you for clearing things up.

 

[Meindert Sprang]

"Michael" <NoSpam@att.net> wrote in message
news:4059BB85.E9F66A71@att.net...

Perhaps all. The really interesting thing though is how the substrate
is prepared to recieve the chip and how the upside-down,
solder-underneath chip is soldered to the substrate.

Thw chip gets tiny solder balls, just like a BGA package. After placing,the
substrate can be soldered on a heat plate.

Meindert

 

[Meindert Sprang]

"Meindert Sprang" <mhsprang@NOcustomSPAMware.nl> wrote in message
news:4059debe$1@news.nb.nu...

"Michael" <NoSpam@att.net> wrote in message
news:4059BB85.E9F66A71@att.net...
Perhaps all. The really interesting thing though is how the substrate
is prepared to recieve the chip and how the upside-down,
solder-underneath chip is soldered to the substrate.

Thw chip gets tiny solder balls, just like a BGA package. After
placing,the
substrate can be soldered on a heat plate.

Shoot, I'm wrong here. The tiny solder balls were for the ceramic carrier,
to form a BGA. The chip was placed on the top side, but I don't remember the
process used. It might be that the solder on the chip was added chemically
through a mask.

Meindert

 

[Martin]

Perhaps all. The really interesting thing though is how the substrate
is prepared to recieve the chip and how the upside-down,
solder-underneath chip is soldered to the substrate.

Interesting, yes. But described very well in many books.
The part not being mentioned is the flipping process itself.

One way, though, is to pick the chips, place ´em in a waffle pack, stack some
of those and flip the entire stack. Then you utilize pattern recognition to
identify each chip before picking and adjust each chip before placing.
There is still ample need for an operator, much more than in the scheme of
picking, flipping, placing with two tweezers or grippers.

I´m just clueless.