Ion implantation method for generating window on dielectric layer

Abstract

The invention relates to a method for forming an opening in a dielectric layer by ion implantation, comprising: providing a base; forming an ion-free dielectric layer on the base; forming a mask layer on the ion-free dielectric layer , the mask layer includes a first opening to expose a portion of the ion-free dielectric layer; using the mask layer, an ion implantation step is performed to form an ion implantation region in the ion-free dielectric layer under the first opening, The depth of the ion implantation region does not exceed the thickness of the ion-free dielectric layer; using the mask layer, a chemical vapor phase etching step is performed to etch the ion implantation region of the ion-free dielectric layer to form a second opening; using the mask layer, A dry etching step is performed to etch the remaining ion-free dielectric layer below the second opening to expose a portion of the substrate. The method effectively reduces critical dimension loss and scratches caused by mask layer loss.

Description

technical field [0001] The present invention relates to a semiconductor manufacturing process, in particular to a method for forming an opening (opening) in a dielectric layer (insulator) by using ion implantation, chemical vapor etching, and dry etching. Methods. Background technique [0002] In processes such as deep contact, deep trench and hardmask, the thickness of the oxide layer to be etched becomes deeper and deeper. However, due to the requirement of resolution in the lithography process, the thickness of the photoresist needs to be reduced. If dry etching is used in the whole process, since plasma is used for dry etching, it is easy to have critical dimension loss caused by photoresist loss. This phenomenon is due to the fact that the plasma also etches the photoresist during dry etching. As the thickness of the oxide layer increases, that is, the etching depth increases, the more the photoresist is etched away, resulting in significant loss. Figure 1A is the th...

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Problems solved by technology

Therefore, chemical wet etching has a high selectivity ratio to photoresist, which can reduce the loss of photoresist, but it is accompanied by severe lateral etching of chemical wet etching, resulting in non-straight contours, which cannot be used actual process

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