Method for making semiconductor device

Abstract

To establish a manufacturing method for switching the outputting form of an output port when information is rewritten to respective elements constituting a mask ROM. The method is provided with a process for forming a gate electrode 8 through a gate insulation film 5 on a semiconductor substrate 1, a process for forming a source-drain area so as to be adjacent to the electrode 8, a process for forming an Al wiring 15 through an interlayer insulation film 14 covering the electrode 8, and a process for injecting impurity ion to the substrate surface layer with a photo resist 23 formed on the Al wiring 15 and the Al wiring 15 as masks to write the information to the respective elements constituting the mask ROM and to switch the outputting form of the output port.

Description

technical field [0001] The present invention relates to a method of manufacturing a semiconductor device, and more specifically to a manufacturing technique for switching the output state of an output terminal when writing information to each element constituting a mask ROM (read only memory). Background technique [0002] In order to shorten the TAT (Turn Around Time) of the mask ROM, various techniques are known for performing ion implantation for information writing (also referred to as program writing and ROM writing) after Al wiring is formed. Next, a conventional manufacturing method will be described using FIG. 6 . [0003] Process 1: if Figure 6A As shown, a pad oxide film 52 made of a silicon oxide film and having a thickness of 25 nm is formed on a P-type semiconductor substrate 51 by thermal oxidation or CVD. The purpose of forming pad oxide film 52 is to protect the surface of semiconductor substrate 51 . [0004] Next, a silicon nitride film 53 as an anti-oxi...

AI Technical Summary

Problems solved by technology

In particular, as described above, corresponding to the plurality of attenuators 32 smaller than the opening for ROM writing, there are other switch forming openings formed so that adjacent openings are adjacent to each other. Tendency to increase influence

[0016] Therefore, there is a problem of insufficient impurity implantation into the channel region of the transistor, which must originally perform ROM writing and switching, resulting in defective writing or switching.

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