Ventilation structure of planarization chamber

A ventilation structure of a planarization chamber for ventilating the inside of a planarization chamber (1) housing a planarization apparatus(100)which prevents scratching of the workpiece by making the flow of air in the planarization chamber substantially laminar and thereby eliminating the rising of the particles or turbulence. The structure includes intake ducts(2-1, 2-2)provided at a ceiling section (10) and having filter units (4-1, 4-2)attached, an exhaust blower (3) attached to a side section (12), and a perforated chamber(5) defined below the ceiling section(10) and having a large number of perforations (52). By making the outside air be ejected from the perforations (52) of the perforated chamber(5) to the inside of the planarization chamber (1), a laminar flow of the air descending to a lower platen (101) side is formed. This laminar flow pushes the particles in the air around the platen(101) down to the floor section (11) side. An exhaust blower (3) exhausts the particles to the outside of the planarization chamber (1).