Fabrication method of flashmemory floating grid and NOR flashmemory

Abstract

The invention relates to a fabrication method of a flashmemory floating grid and an NOR flashmemory. A tunneling oxide layer, a floating grid layer and a hard mask layer are sequentially laminated andformed on a semiconductor substrate, the hard mask layer, the floating grid layer, the tunneling oxide layer and the semiconductor substrate are etched, a plurality of isolation grooves are formed inthe semiconductor substrate, groove oxide layers are formed on inner walls of the grooves, isolation mediums are filled so that the isolation mediums are flush with an upper surface of the hard masklayer, the isolation mediums are etched to form isolation structures, and the hard mask layer is finally removed to form floating grids among the isolation structures. Compared with a method of filling the gaps among the isolation mediums with the floating gird layer in the prior art, the fabrication method has the advantages that the problem that the filling difficulty of the floating grid layeris improved with the increase of depth-to-width ratio of the gaps; and the hard mask layer covers the floating grid layer, a chemical mechanical polishing (CMP) process is prevented from being directly acted on the floating grid layers, and the influence of the isolation medium etching process on the tunneling oxide layer is relatively small.

Description

technical field [0001] The invention relates to the field of semiconductor technology, in particular to a manufacturing method of a flash memory floating gate and a NOR flash memory. Background technique [0002] With the development of semiconductor technology, flash memory (flash memory) has been widely used as a non-volatile memory. The flash memory adds a floating gate and a tunnel oxide layer on the basis of the traditional MOS transistor structure, and uses the floating gate to store charges, thereby realizing non-volatile storage content. [0003] NAND flash memory and NOR flash memory are two important non-volatile flash memory technologies in the market today. Among them, NOR flash memory can perform independent read and write operations on each storage unit, providing a complete random access function, so it can be used for non-volatile storage of executable programs, while NAND flash memory cannot provide complete random access The fetch function is used to inde...

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Problems solved by technology

[0006] The object of the present invention is to provide a method for manufacturing floating gates of flash memory and NOR flash memory, so as to solve the problem of increasing difficulty in filling the floating gate layer as the process node decreases in the existing floating gate manufacturing process of flash memory

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