Method for making silicon nitride ROM

Abstract

A method for manufacturing a silicon nitride read-only memory, comprising sequentially forming a first oxide layer, a capture layer, and a second oxide layer on a substrate, and then forming a mask pattern on the second oxide layer as an implant mask, and performing a Ion implantation process to form buried bit lines in the substrate. Then remove part of the mask pattern and the second oxide layer and capture layer not covered by the mask pattern, so as to increase the gap size of the mask pattern and expose part of the first oxide layer. Then, using the mask pattern as an implantation mask, a pocket ion implantation process is performed to form a pocket-type doped region around the contour of the buried bit line. Next, the mask pattern is removed, and the capture layer is used as a mask for heat treatment to form a buried bit line oxide layer on the substrate, and finally a word line is formed on the substrate.

Description

technical field [0001] The present invention relates to a method for manufacturing a semiconductor component, and in particular to a method for manufacturing a substrate / silicon oxide / silicon nitride / silicon oxide / silicon (Substrate / Oxide / Nitride / Oxide / Silicon, referred to as SONOS) component . Background technique [0002] figure 1 is a cross-sectional view of a known substrate / silicon oxide / silicon nitride / silicon oxide / silicon assembly. [0003] Please refer to figure 1 There is a layer of word lines 104 on the substrate 100, and between the substrate 100 and the word lines 104, there is a composite layer 102 composed of silicon oxide / silicon nitride / silicon oxide (Oxide / Nitride / Oxide, ONO for short) as a capture layer. (Trapping Layer) stacked (Stacked) structure, and the substrate 100 on both sides of the ONO layer 102 has a buried bit line 106, and a buried bit line oxide layer 108 is located on the buried bit line 106 Between the buried bit line 106 and the word l...

AI Technical Summary

Problems solved by technology

Therefore, when carrying out the pocket ion implantation process 212, it is necessary to use a large-angle implantation, so the ion implantation process is more complicated and the reliability is lower.

Moreover, the formed pocket-type doped region 214 cannot cover the contour of the buried bit line 206 well, so it is easy to cause the phenomenon of breakdown (Punch-Through)

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