Single-chip designs have previously been hard to design and manufacture. However, instead of soldering the components together using conventional methods:

'The modules are assembled using conductive adhesive with industrial surface mounting technology on a thin double-sided flexible printed circuit board. The final shape of the microrobots is achieved by folding the flexible printed circuit board twice.'

Different modules allow the robot to communicate, move, store energy, and collect data. The tiny robots, less than 4mm in any direction, contain a solar cell on top for power, and vibrating legs, three of which they use to move and one that acts as a touch sensor.

Although not powerful as individuals, the intent is to use the I-SWARM (intelligent small-world autonomous robots for micro-manipulation) concept to create ravening hordes of tiny robots working in concert to destroy even the mightiest works of man!

Well, okay, maybe that's getting a bit ahead of the actual technology. However, older readers of Stanislaw Lem have been nervously scanning their surroundings for these things ever since the 1954 publication of The Invincible.

"What is the nature of this cloud? What is your opinion?" he asked without any introductory remarks.

"It is made up of tiny metal particles. A remote-controlled emulsion, as it were, with uniform center," answered Jazon...

"...I believe them to be very tiny pseudo insects that, if necessary, and for their common good, can unite to form a superordinate system. This is the course taken by the evolution of the mobile mechanisms."

(Read more about Lem's nanomachine swarm)

I'd also add a reference to a more structured version of this idea, the Robot Cells (Crystal-Shaped Modules) from 1987 work by Michael P. Kube-McDowell.

Update: In his 1920 novel The Metal Monster, Abraham Merritt envisions this same idea, describing living metal cubes that work together to form different strutures "as though a child should build from nursery blocks a fantastic shape which abruptly is filled with throbbing life.":

"...They were such LITTLE THINGS," muttered Drake. "Such little things—bits of metal—little globes and pyramids and cubes—just little THINGS..."

"Bits of metal"—Dick's gaze sought mine, held it—"and they looked for each other, they worked with each other—THINKINGLY, CONSCIOUSLY—they were deliberate, purposeful—little things—and with the force of a score of dynamos—living, THINKING—"

Thanks to Blue Monkey for contributing the tip on this item. End update.

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