Method of manufacturing mask read-only memory

Abstract

The present invention discloses a method of manufacturing a mask read-only memory. After a grid and a side wall of the grid are finished, a layer of interlayer medium is deposited and flattened, so that a later made island type pattern stands on the grid more firmly. The photoetching process windows are increased, and a deposited medium layer adapts a part of or the whole contacting hole medium layer without needing additional growth or removing, thereby not increasing the manufacture cost additionally.

Description

technical field [0001] The invention relates to the field of semiconductor integrated circuit manufacturing, in particular to a mask read-only memory manufacturing method. Background technique [0002] Mask Read Only Memory (MROM: Mask Read Only Memory) is the most basic read-only memory, widely used in electronic products. The mask read-only memory uses a photomask to selectively implant ions into a plurality of coding regions, so as to determine the connection state of each transistor in the memory cell array, and achieve the purpose of storing data. When the product changes, there is no need to make major changes to the production process, just replace the photomask, which is very conducive to mass production. Compared with EEPROM or Flash, mask read-only memory occupies a very small area, which is beneficial to reduce costs and realize large-capacity storage. [0003] The manufacturing process of the existing mask read-only memory mainly includes the following steps: t...

AI Technical Summary

Problems solved by technology

in, figure 1 In the actual process control of the island structure shown, the photolithography process window is very small, and the phenomenon of island pattern drift (such as image 3 As shown), the place that does not need ion implantation will be implanted, and the place that needs to be implanted may be blocked by the drifting island pattern, so that the entire memory cell will fail

At present, the analysis reason is mainly because the island pattern is formed on the gate, the island pattern protrudes from both sides of the gate, and the gap between the gates is in a suspended state, such as Figure 4 shown, prone to tilting

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