| 摘要 |
PURPOSE:To reduce the damage to a wafer during ashing by controlling the density of a plasma by an electromagnet. CONSTITUTION:When O2 gas is introduced into an ashing unit to emit a microwave through a microwave transmitting window to gas, an O2 plasma is generated. An electromagnet 18 is deenergized to pass the plasma 19 to arrive at a wafer to ash a resist 16. This has the same strong ashing force as a barrel type plasma ashing apparatus to remove a modified layer feasibly generated at the resist after ion implanting. When the modified layer is removed by ashing to allow the normal resist to remain, the plasma cannot pass by the magnetic force when the electromagnet 18 is energized so that active particles merely arrive at the wafer 17 to ash the resist 16. This is the same as a down-flow type ashing apparatus, and the ashing with the active particles less damages the wafer than the O2 plasma.
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