Do you mean the phalanx?
If so, yes, as did most hoplite based armies (Athens, Melos, Knossos etc). The phalanx was usually fought with 8 rows (or more) of men pushing against each other with overlapping shields in the front. Obviously, this would make it incredibly difficult to break the formation with just a frontal assault, but leaves the unit heavily vulnerable on the flanks. Arguably the most famous example of this would be the Battle of Thermopylae in which the Greek forces funneled Xerxes' army directly into the phalanx, inflicting significant casualties. This is also a great example of the formations greatest weakness. When the Persian soldiers managed to get around to the rear, the hoplites were forced to abandon the formation and were slaughtered.
Sources
http://academic.reed.edu/humanities/110tech/thermopylae.html
http://www.ancient.eu/article/110/
http://www.britannica.com/EBchecked/topic/454991/phalanx
Of course, if you weren't talking about the Phalanx then ignore this.
