Structure for monitoring etching back depth and monitoring method

Abstract

The invention relates to a structure for monitoring an etching back depth and a monitoring method. According to the monitoring structure, the structure is a groove that is manufactured at a wafer non-element zone and has a trapezoidal surface cross section. The monitoring method is characterized in that the trapezoidal groove is used to obtain a distribution inflection point of a sediment after the etching back process; and according to the inflection point position, whether the etching back depth meets the requirement or not can be determined. According to the monitoring method, only simple auxiliary equipment is needed. Therefore, compared with the original monitoring means, the monitoring method enables the cost to be substantially lowered; the operation is simple and the result is accurate; and the method is suitable for assembly line type on-line monitoring. In addition, the monitoring structure only occurs at the intermediate process of the whole DMOS device manufacturing technology and thus no negative effect is caused on the finished product. The structure has the high practicability.

Description

technical field [0001] The invention relates to the field of manufacturing semiconductor devices, in particular to a structure and a monitoring method for monitoring the etching-back depth in the etching-back process. Background technique [0002] A DMOS (Double Diffused MOS) transistor is a transistor of the MOSFET (Metal Oxide Semiconductor Field Effect Transistor) type that uses two sequential diffusion steps aligned on the same edge to form the channel region of the transistor. DMOS transistors are usually high-voltage, high-current devices used as discrete transistors or components in power integrated circuits. DMOS transistors can deliver high current per cell area with low forward voltage drop. [0003] A specific type of DMOS transistor is the so-called trench DMOS transistor, in which the channel appears on the inner wall of the trench extending from the source to the drain, and the gate is formed in the trench. Polysilicon-filled trenches aligned with a thin oxid...

AI Technical Summary

Problems solved by technology

For the second method, with the reduction of the critical size of the device, the requirements for the probe of the step meter are getting higher and higher, and the price of the step meter with high precision is extremely expensive, which undoubtedly increases the initial cost of testing. It also requires high maintenance costs

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