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Technology

Technology nodes from 10 µm to 2 nm

NODE SCALE

10 µm 2 nm

Selected: 350 nm
10 µm 3 µm 1,5 µm 1 µm 800 nm 600 nm 350 nm 250 nm 180 nm 130 nm 90 nm 65 nm 45 nm 32 nm 22 nm 16 nm 11 nm 7 nm 5 nm 3 nm 2 nm

Technology node · 350 nm

350 nm (0.35 µm)

The 350 nm process refers to the manufacturing technology that came into use at leading semiconductor manufacturers from 1995 onward. This node marks the end of the mercury-vapor lamp era.

The i-line at 365.01 nm can no longer be economically pushed far enough for structures of this size. Excimer lasers are therefore used for the critical layers, initially krypton fluoride at 248 nm. This requires a complete change in the resist system: conventional novolac resists absorb too strongly in the deep ultraviolet. They are replaced by chemically amplified resists, in which exposure merely releases an acid that subsequently breaks many bonds in a catalytic process. This means that only a small amount of light is required – but the resist also becomes sensitive to delays between exposure and baking as well as to alkaline traces in the cleanroom air.

At the same time, LOCOS begins to reach its limits. The isolation oxide grows laterally beneath the nitride mask, forming the so-called bird's beak, which consumes area that cannot be scaled down proportionally. It is replaced by trench isolation: a narrow trench is etched, filled with oxide and planarized using CMP. It requires hardly any more space than its intended width.

Processors manufactured in 350 nm (selection):
  • Intel Pentium Pro (1996, later versions)
  • Intel Pentium MMX (1997)
  • AMD K6 (1997)