What is the term for the later Cubist phase that used collage?

The later Cubist phase that used collage is called Synthetic Cubism.

Synthetic Cubism emerged around 1912 after the more analytical experiments of 1908–1912. Analytic Cubism broke subjects into overlapping, faceted planes and often used subdued browns and grays. Synthetic Cubism instead rebuilt images from simpler shapes, brighter colors, signs, letters, and recognizable fragments.

Collage was central to this change. Georges Braque introduced papier collé, or “pasted paper,” by attaching pieces of faux-wood wallpaper to a drawing in 1912. Pablo Picasso soon explored related constructions, incorporating newspaper, sheet music, labels, and other everyday materials. These works challenged the traditional idea that a painting had to imitate the visible world with paint alone.

Synthetic does not mean that the artists returned to ordinary realism. Their compositions remained deliberately constructed and ambiguous. A pasted newspaper fragment might suggest a table, a newspaper, or simply a flat pattern. The technique also influenced later collage, assemblage, Dada, and modern design. Tubism was not a standard Cubist phase, while Orphism was a related but distinct movement.