In the spring of 1958, Hoerni and Last were spending nights on experiments with the first planar transistors.[87] The planar technology later became the second most important event in the history of microelectronics, after the invention of the transistor, but in 1959 it went unnoticed.[88] Fairchild announced the transition from mesa to planar technology in October 1960.[89] However, Moore refused to credit this achievement to Hoerni, and in 1996 even attributing it to unnamed Fairchild engineers.[30]