Preparation method for flash memory

Abstract

The invention provides a preparation method for a flash memory. Oxidation processing is performed on a semiconductor substrate with formation of a tunneling oxidation layer before formation of a floating gate so that stability of an active region surface contacted with the tunneling oxidation layer is enhanced. Meanwhile, deposition thickness of a metal layer for preparation of a metal silicide is reduced, and heat treatment for formation of the metal silicide is performed via two divided phases so that enhancement of stability and surface uniformity of the metal silicide is facilitated, wherein temperature of the second phase of heat treatment is higher than that of the first phase, and time of the second phase of heat treatment is shorter than that of the first phase. With application of the aforementioned method, the metal silicide can be prevented from irregularly eroding to the gate structure and the contact surface of the active region so that programming interference caused by irregular erosion can be reduced, an objective of suppressing programming interference of the flash memory is achieved, reduction of reliability of a drain region in cycle operation can be further avoided, and generation of tail bits of data retention of the flash memory can also be avoided.

Description

technical field [0001] The invention belongs to the manufacturing field of semiconductor devices, and relates to a preparation method of a flash memory. Background technique [0002] Flash memory (Flash Memory, referred to as flash memory) is a programmable erasable, non-volatile, non-volatile semiconductor memory developed on the basis of the manufacturing technology of EPROM and EEPROM. The advantage of large capacity, and overcome the defects of DRAM and SRAM that lose the stored data when the power is cut off, has become one of the mainstream research in the industry. [0003] Flash memory has been used in thousands of products, including mobile phones, laptops, PDAs, and USB flash drives, because of its ability to retain data in the event of a power failure and the ability to rewrite data multiple times. , and in industrial products such as network routers and cabin recorders. The development of flash memory cells with low power consumption, high reliability and fast ...

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Problems solved by technology

[0010] In view of the above-mentioned shortcomings of the prior art, the object of the present invention is to provide a method for preparing a flash memory, which is used to solve the problem in the prior art that the metal silicide corrodes irregularly to the contact surface of the gate structure and the active region , which is further used to solve the problem of how to use a simple process in the prior art to make the flash memory effectively avoid programming disturbance

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