Silicon nitride memory and a process for making it

Abstract

The invention discloses a silicon nitride memory and a process for making it comprising, forming in sequence an electric charge trapping layer and a first photoresistive layer on a substrate, then using the photoresistive layer as a ion implanting shielding screen to form a bit line in the substrate. later forming a first lining layer not reacting with the electric charge trapping layer on at least the side surface of the photoresistive layer, and using the first lining layer and the photoresistive layer as an etching shielding screen figuring electric charge trapping layer to form a bar shape electric discharge trapping layer. After removing the first lining layer and the photoresistive layer, forming a insulation layer on the substrate surface above the bit line, and forming a character line on the bar shape electric discharge trapping layer and the insulation layer at a direction perpendicular to the bit line direction. Later forming a second lining layer not reacting with the bar shape electric charge trapping layer on the surface of the character line, then using the second lining layer as an etching shielding screen figuring electric charge trapping layer to form a plurality of block shape electric discharge trapping layer, then removing the second lining layer.

Description

technical field [0001] The present invention relates to a memory device and its manufacturing method, and in particular to a silicon nitride memory device (Nitride ROM, NROM) and its manufacturing method. Background technique [0002] Flash memory is an electrically erasable programmable read-only memory (EEPROM), which has the advantages of being writable, erasable, and able to save data after power failure, and is widely used in personal computers and electronic devices. memory device. In addition, flash memory is a kind of non-volatile memory (Non-Volatile Memory; NVM), which has the advantages of small size, fast access speed and low power consumption, and because of its data erasing (Erasing) When using the "block by block" (Block by Block) erasing method, it has the advantage of faster operation. [0003] Typical flash memory uses doped polysilicon to make the floating gate and control gate. When programming (Program), the electrons injected into the floating gate w...

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Problems solved by technology

Therefore, it is very difficult to form a charge trapping layer pattern or pitch smaller than 0.15 microns to solve the above leakage current situation under the limitation of the current lithography process.

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