METHOD FOR FORMING MULTIPLE GATE OXIDE LAYER TO PREVENT CHARACTERISTIC AND RELIABILITY OF DEVICE FROM BEING DETERIORATED BY IMPURITIES AS GATE OXIDE LAYER IS REDUCED IN THICKNESS

摘要

PURPOSE: A method for forming a multiple gate oxide layer is provided to prevent a characteristic and reliability of a device from being deteriorated by impurities as a gate oxide layer is reduced in thickness by patterning an anti-oxide layer while impurities are not introduced. CONSTITUTION: An anti-oxide layer is deposited on a silicon substrate(100). Photoresist is formed on the anti-oxide layer and is patterned to be a predetermined shape. By using the patterned photoresist of the predetermine shape as a mask, the anti-oxide layer in a portion for forming the thickest oxide layer is removed by the first photolithography process. The first gate oxide layer(110) is formed by a rapid thermal process. Photoresist is formed on the first gate oxide layer and the anti-oxide layer. The photoresist is patterned to be a predetermined shape and the anti-oxide layer is etched by using the patterned photoresist as a mask. After the patterned photoresist is eliminated, the second gate oxide layer(112) is formed by a rapid thermal process. After the remaining anti-oxide layer is wet-etched, the third gate oxide layer(114) is formed by a rapid thermal process.