Stop motion animation :

Stop motion (also known as stop action or frame-by-frame) is an animation technique to make a physically manipulated object appear to move on its own. The object is moved in small increments between individually photographed frames, creating the illusion of movement when the series of frames is played as a continuous sequence. Clay figures are often used in stop motion for their ease of repositioning. Motion animation using clay is called clay animation or clay-mation.

1980s to present : 

In the 1970s and 1980s, Industrial Light & Magic often used stop motion model animation for films such as the original Star Wars trilogy: the chess sequence in Star Wars, the Tauntauns and AT-AT walkers in The Empire Strikes Back, and various Imperial machines in Return of the Jedi are all stop motion animation, some of it using the Go films. The many shots including the ghosts in Raiders of the Lost Ark and the first two feature films in the RoboCop series use Phil Tippett's Go Motion version of stop motion.

Stop motion was also used for some shots of the final sequence of Terminator movie, as they were for the scenes of the small alien ships in Spielberg's Batteries Not Included in 1987, animated by David W. Allen. Allen's stop motion work can also be seen in such feature films as The Crater Lake Monster (1977), Q - The Winged Serpent (1982), The Gate (1986) and Freaked (1993). Allen's King Kong Volkswagen commercial from the 1970s is now legendary among model animation enthusiasts.

Reference :
http://en.wikipedia.org/wiki/Stop_motion