The invention provides an
etching method for improving the uniformity of the
contact hole line width. The method comprises the steps that an optical
line width measurement instrument is used for measuring and collecting
contact hole line width full-mapping data on wafers of the prior batch, so that a
database is established; the average value of the
contact hole line width full-mapping data of the middle portions of the wafers of the prior batch and the contact hole line width full-mapping data of the edges of the wafers of the prior batch is compared with the value of the contact hole line width required by the technology through the
database, so that the width difference of the middle portions of the wafers of the prior batch and the width difference of the edges of the wafers of the prior batch are obtained respectively; according to the width difference of the middle portions of the wafers of the prior batch and the width difference of the edges of the wafers of the prior batch, the
etching gas flow of the middle portions of wafers of a later batch and the
etching gas flow of the edges of the wafers of the later batch are respectively adjusted through an APC
system; in the contact hole etching technology steps, the etching gas flow of the wafers of the later batch is corrected in real time through the APC
system, so that influence, caused by the photoetching difference of the wafers of the prior batch, on photoetching of the wafers of the later batch can be avoided, the shortages that the gas flow of the middle portions and the edges of the wafers is not changed in the contact hole etching technology are overcome, and the gas flow change of each portion is accurately mastered.