Flash Life Prediction Methods and Screening Methods

Abstract

A flash memory service predicting method and a flash memory screening method. The flash memory service predicting method includes the steps of: detecting the residual currents within several different waiting time values after a sampled flash memory after erasure; according to the several different waiting time values and the residual currents of the sampled flash memory, performing fitting to obtain a first mapping relationship between the residual currents and the natural logarithms of waiting time values, wherein the first mapping relationship is linear; according to the first mapping relationship, calculating a required waiting time value that the residual current of the to-be-predicted flash memory reduces to a preset failure residual current to obtain the service life of the to-be-predicted flash memory. The flash memory service predicting method and a flash memory screening method improve the accuracy and convenience of flash memory service prediction and flash memory screening.

Description

technical field [0001] The invention relates to the technical field of semiconductors, in particular to a flash memory lifetime prediction method and screening method. Background technique [0002] In the current semiconductor industry, integrated circuit products can be mainly divided into three types: analog circuits, digital circuits and digital / analog hybrid circuits, among which storage devices are an important type of digital circuits. In recent years, among storage devices, flash memory (flash memory, referred to as flash memory) has developed particularly rapidly. The main feature of flash memory is that it can keep stored information for a long time without power on; and it has high integration, high access speed Fast, easy to erase and rewrite, etc., so it has been widely used in many fields such as microcomputers and automatic control. [0003] In the prior art, the standard physical structure of the flash memory is called a storage unit (bit). The structure of ...

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Problems solved by technology

[0004] However, in the process of forming the oxide layer of flash memory, impurities such as chloride ions will remain in the oxide layer, and excessive chloride ions form chlorine traps (Cl traps), and the charges stored in the floating gate of flash memory will leak through the chlorine traps, resulting in The ability of the flash memory floating gate to store charges decreases, and the flash memory gradually fails

With the different chloride ion content in the oxide layer, the failure time of flash memory is also different, which makes it more difficult to screen out flash memory with different service life

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