Structure of non-volatile memory and producing method thereof

Abstract

A manufacturing method for non-volatile memory, first forms a strip dielectric layer on a base, and forms a flush type bit line in the base at the both sides of the dielectric layer. Then patternize the strip dielectric layer, to form several massive dielectric layer, afterwards forms a coding mask layer, expose part of massive dielectric layer. Then takes coding mask layer as a etching mask, detaches the exposure part of the strip massive dielectric layer. After detaching the coding mask layer, form a gate dielectric layer, further form a word ling on the base.

Description

technical field [0001] The present invention relates to a structure of a non-volatile memory and its manufacturing method, and in particular to a mask ROM (Mask ROM) structure and its manufacturing method. Background technique [0002] The structure of a general mask ROM includes several bit lines (Bit Line, BL) and several polysilicon word lines (Word Line, WL) straddling the bit lines. The area below the word line and between two adjacent bit lines is the channel area of ​​the memory cell. For some mask ROMs, the programming method is to store data "0" or "1" by whether ions are implanted in the channel or not. The process of implanting ions in specific channel regions is also called code implantation process. [0003] Generally, the code implantation process of the mask read-only memory is to firstly use a photomask to pattern the photoresist layer formed on the substrate, so as to expose the desired code implantation region. Then, an ion implantation process is perfor...

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Problems solved by technology

However, this method must design a mask with a special pattern

Therefore, in addition to the time-consuming production of the photomask, it also increases the difficulty and cost of manufacturing the photomask.

In addition, it is extremely difficult to improve (debug) the defects of the mask pattern after the mask is manufactured.

[0005] In addition, in the known method, if the code mask used in the code implantation process has the problem of misalignment or critical dimension deviation, the code ions originally planned to be implanted in the channel region will also diffuse to the implanted channel area. bit line

In this way, the ion concentration in the buried bit line will change, and the current of the buried bit line will be insufficient.

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