Did Max Planck originally claim that light itself was made of particles?

No, Max Planck did not originally claim that light itself was made of particles.

In his 1900 work on blackbody radiation, Planck introduced the concept of quanta to describe how the oscillators within a blackbody absorb and emit energy. He proposed that these oscillators could only exchange energy in discrete amounts, or quanta, proportional to their frequency.1

Planck viewed this as a mathematical necessity to derive his radiation law rather than a physical statement about the nature of light itself. In fact, he remained a "reluctant revolutionary" who struggled for years to reconcile his findings with classical wave theory. It was Albert Einstein who, in 1905, independently proposed that radiant energy itself—light—consisted of discrete quanta, which were later termed photons.12