Method for on-line monitoring of quality of ONO (Oxide-Nitride-Oxide) film in SONOS (Silicon Oxide Nitride Oxide Semiconductor) memory process

A memory and process technology, applied in the field of monitoring ONO film quality, can solve the problems of production line risk, inability to judge the quality of ONO film in real time, etc., to avoid the effect of influence

CN102543214BActive Publication Date: 2014-08-13SHANGHAI HUAHONG GRACE SEMICON MFG CORP
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Patent Information

Authority / Receiving Office
CN · China
Patent Type
Patents(China)
Current Assignee / Owner
Publication Date
2014-08-13

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Abstract

The invention discloses a method for on-line monitoring of the quality of an ONO (Oxide-Nitride-Oxide) film in SONOS (Silicon Oxide Nitride Oxide Semiconductor) memory process. The method comprises: 1) grounding a body region, a source port and a drain port of an SONOS memory structure; 2) supplying forward current less than 1muA to a grid port of the SONOS memory structure and lasting for 20-30 seconds; 3) successively supplying a reverse current less than 1nA to the grid port, scanning the voltage of the grid port and drawing a voltage-time curve; 4) carrying out integration to calculate out the area surrounded by the drawn voltage-time curve and the lateral axis of a coordinate; 5) comparing the numerical value obtained in step 4) with a standard numerical value so as to judge the quality of the ONO film. With the method, a device can be tested once being produced and monitored in real time, so that the result can be fed back to the production line in time, and the influence on the production line due to delayed judgment can be avoided.
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Description

technical field

[0001] The invention relates to a method for monitoring the quality of an ONO film, in particular to an online method for monitoring the quality of an ONO film. Background technique

[0002] SONOS structure, namely silicon, silicon oxide, silicon nitride, silicon oxide and polysilicon (bottom-up) five kinds of materials stacked composite gate structure. The SONOS structure is extremely compatible with standard CMOS technology, and has many advantages such as high durability, low power and radiation resistance. In addition, the SONOS architecture provides a more stable, easier-to-manufacture and cost-effective solution than other embedded non-volatile memory technologies. This technology is also widely used in the industry because of its compact structure and its ability to extend downwards.

[0003] In the SONOS memory process, the preparation of ONO film is the core process. The quality of the ONO film directly determines the performance and reliability o...

Examples

Embodiment Construction

[0018] The method for on-line monitoring of the quality of the ONO film of the present invention is a creative proposal to use the method of charge capture and release to detect the quality of the ONO film on-line. The method simulates writing and erasing of the SONOS structure memory by means of forward injection and reverse extraction of stable current. During the current reverse extraction process, the reverse voltage is sampled and scanned, and the area enclosed by the scanned V-t (voltage-time) curve and the coordinate horizontal axis is calculated by integration. The physical meaning of the obtained area is the ability of the defects in the film to capture electrons. Therefore, the area value obtained by the integral is used to evaluate the quality of the ONO film.

[0019] Method of the present invention, after forming SONOS core device (that is to have formed the gate of SONOS memory, source region, drain region and body region) structure is test structure, specifical...