Method and apparatus for detecting polysilicon gate etching terminal

Abstract

This invention is a kind of end point checking method and checking apparatus of polycrystalline silicon grating etching. The etching process has four steps which have different end point checking method. Bias voltage compensating end point checking predicts the end point of etching process that has relative low etching selecting rate. Use this sensitive method can ensure oxidation layer pre-protected before etching drawing near grate oxygen. Though OES end point checking method, checking etching process of high selecting rate ensures polycrystalline silicon etched fully and grate oxygen layer protected effectively.

Description

technical field [0001] The invention relates to the technical field of microelectronics, in particular to a detection method and a detection device for the etching end point of a polysilicon gate. Background technique [0002] In the manufacture of semiconductor devices, such as the manufacture of integrated circuits or liquid crystal flat panel displays, the raw material for the substrates of these products is generally polysilicon. The polysilicon wafer structure is as follows: [0003] The bottom layer is a silicon wafer; a thin gate silicon oxide of 10-30 angstroms is grown on the silicon wafer; a layer of polysilicon is grown on the gate silicon oxide of 1000-3000 angstroms; a hard mask is grown on the polysilicon; the hard mask can be silicon oxide, nitrogen Silicon oxide, silicon oxynitride; the top of the silicon wafer is the photoresist pattern after photolithography. [0004] The substrate generally needs to be produced in a plasma chamber environment, and photol...

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Problems solved by technology

In this case, the OES endpoint detection method relying only on the plasma emission spectrum cannot reliably protect the gate oxide layer.

[0009] U.S. Patent (U.S 622827) provides a novel endpoint detection method, which uses a bias voltage compensation electrostatic chuck, and performs endpoint detection by monitoring the substrate potential, compensation current or compensation voltage, however, the method Very sensitive, it is difficult to directly control the etching end point

That is to say, relying only on this method is not enough to satisfy polysilicon etching sufficiently and effectively protect the gate oxide of a few nanometers.

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