Anyways none of you are being conspiratorial enough.
OK here we go:
They're probably not chips in the traditional silicon sense. A lot of research has been undertaken into organic computers. Similarly it's been known that some virus types can control their hosts to a certain extent. So combine the two in some seedy black ops lab.
Then give every one in the world a nasty cold (made in China of course due to the volumes needed) and then miraculously come up with a 'vaccine' of the 'dead' black ops virus particles. No problems then with chip implants or making sure they're spread throughout the vaccine vials to ensure even distribution in injections. The virus particles then migrate to the neurons and then the programming activates....
No trace, nothing showing on the metal detectors, and annual programming updates given by the booster jabs. Different 'vaccines' can have different programming depending o one's role in the new world order.