Structure of mask ROM and method for manufacturing the same

Abstract

A method for manufacturing a mask-type read-only memory, the method sequentially forms a silicon monoxide / silicon nitride / silicon oxide composite layer and a plurality of gates on a substrate, and the silicon oxide between any gate and the substrate / silicon nitride / silicon oxide composite layer as a predetermined coding area. Then, a plurality of bit lines are formed in the substrate between the gates, and a plurality of word lines electrically connected with the gates are formed on the substrate. Then, a chemical vapor deposition anti-reflection material layer and an inner dielectric layer are formed on the substrate. Then, an encoding process is carried out, using the chemical vapor deposition anti-reflection layer as the encoding mask, and irradiating the substrate with ultraviolet light, so that the predetermined encoding area under the gate exposed by the encoding window forms a plurality of writing encoding areas, and then writes in the encoding window A plug is formed inside.

Description

technical field [0001] The present invention relates to a structure and a manufacturing method of a read-only memory (ROM), and in particular to a structure and a manufacturing method of a mask-mode read-only memory (Mask ROM). Background technique [0002] Since the read-only memory has the non-volatile characteristic that the data stored therein will not be lost due to power interruption, many electrical products must have this type of memory in order to maintain the normal operation of the electrical product when it is turned on. The most basic type of read-only memory is the mask-mode read-only memory. Generally, the commonly used mask-mode read-only memory uses channel transistors as storage units, and selectively implants ions into designated channels during the programming (Program) stage. area, by changing the threshold voltage (Threshold Voltage) to achieve the purpose of controlling the memory cell to be turned on (On) or turned off (Off) during the read operation....

AI Technical Summary

Problems solved by technology

Such ROMs take longer to order and require a dedicated code mask for the channel ion implantation step

Moreover, when the channel ion implantation step is performed, if the position of the ion implantation block is misaligned, it will directly affect the operating characteristics of the storage unit, causing data errors in the ROM storage unit, resulting in product failures. worsening reliability

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