Flash memory device forming method

Abstract

A flash memory device forming method is disclosed and comprises the following steps: a semiconductor substrate having word line digit line zones and source line floating gate zones, floating gate oxidation layers and floating gate layers that stretch across the word line digit line zones and the source line floating gate zones are formed on parts of the semiconductor substrate, isolating layers positioned at two sides of the floating gate oxidation layers and the floating gate layers are formed in the semiconductor substrate, dielectric layers covering the word line digit line zones are formed, first openings are arranged between the dielectric layers, first side walls are formed on side walls of the first openings, the floating gate layers and the floating gate oxidation layers positioned at bottom parts of the first openings are removed, and second openings are therefore formed; in the first openings and the second openings, source line films are formed on the first side walls and the dielectric layers, the source line films on the first side walls and the dielectric layers are removed via grinding operation, and an excessive grinding amount in grinding processes can be obtained according to distance between surfaces of top parts of the isolating layers and surfaces of top parts of the floating gate layers; after the dielectric layers, the floating gate layers and the floating gate oxidation layers at the word line digit line zones, word line structures are formed at the word line digit line zones. Via use of the method, a programming crosstalk failure occurrence can be lowered.

Description

technical field [0001] The invention relates to the field of semiconductor manufacturing, in particular to a method for forming a flash memory. Background technique [0002] Flash memory is an important device in integrated circuit products. The main feature of flash memory is that it can keep stored information for a long time without applying voltage. Flash memory has the advantages of high integration, fast access speed and easy erasing, so it is widely used. [0003] Flash memory is classified into two types: stack gate flash memory and split gate flash memory. The stacked gate flash memory has a floating gate and a control gate above the floating gate. The stacked gate flash memory has the problem of over-erasing. Different from the stacked gate flash memory, the split gate flash memory forms a word line as an erasing gate on one side of the floating gate. The split-gate flash memory can effectively avoid the over-erasing effect. In addition, the split-gate flash ...

AI Technical Summary

Problems solved by technology

[0004] However, the existing split-gate flash memory has a serious problem of programming crosstalk failure

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