Method for etching of silicon nitride films si3n4

FIELD: physics, semiconductors.

SUBSTANCE: invention is related to technology for making semiconductor instruments and integrated circuits, in particular, to methods for etching of film dielectrics, from which silicon nitride is most widely used. Invention makes it possible to get even relief of profile in process of plasma-chemical etching of silicon nitride films with quite high speed and repeatability of process. In method of plasma chemical etching of silicon nitride films, gas phase components are Freon and oxygen at the following ratio of components: Freon : O2=7 l/hr : 0.6 l/hr at working pressure of P=205 Pa and speed of 355 nm/min.

EFFECT: makes it possible to get even relief of profile in process of plasma-chemical etching of silicon nitride films with quite high speed and repeatability of process.

 

The invention relates to the technology of manufacturing semiconductor devices and IP, in particular to a method of etching a film dielectrics, of which the most widely used is silicon nitride.

Known methods of etching dielectric films, the essence of which consists in etching the nitride film of silicon by ion-beam and ion-plasma etching, where the etching process occurs according to the mechanism of physical dispersion. Reactive methods that comprises plasma etching, reactive ion-beam etching, based on various combinations of chemical reactions, during which the formation of volatile or quasilattice connections, and physical interactions, such as ion bombardment [1].

The main disadvantage of this method are the low etching rate, the irreproducibility of the etching process, obtaining an uneven profile of etched film, the use of high pressures (up to 133 PA).

The aim of the invention is to obtain smooth terrain profile in plasma-chemical etching of the film of silicon nitride with high speed and reproducibility of the process.

This goal is achieved by the fact that as the gaseous components using halon and oxygen in the following ratio of components: halon 7 LCH; oxygen - 0.6 l/h

The essence of the method is that the surface of the substrate with a film of silicon nitride is processed through a chemical reaction of a gas mixture consisting of halon and oxygen flowing on the surface of the film.

The proposed method differs from the prototype in that the substrate is subjected to plasma treatment with a gas mixture comprising refrigerant and oxygen in the ratio of 7 l/h:0.6 l/h at an operating pressure P=205 PA at a speed of 305 nm/min

Summary of the invention the following examples.

EXAMPLE 1. The etching process with high resolution is carried out in a reactor with electrodes in the form of parallel plates. And as substrates when developing and optimizing modes were used plate of silicon nitride, on which was deposited a photoresist. The process is carried out in a gas mixture consisting of halon with oxygen (halon-O2) in the ratio of 9 l/h:0.8 l/h at an operating pressure P=305 PA at 25 nm/ min

EXAMPLE 2. The method is carried out analogously to example 1. The process is carried out at a ratio of:

halon:O2=8 l/h:0.7 l/h, -

when the pressure is P=305 PA at 25 nm/min

EXAMPLE 3. The method is carried out analogously to example 1. The process is carried out at a ratio of:

halon:O2=8 l/h:0.6 l/h, -

at an operating pressure of 305 PA at 25 nm/min

<> EXAMPLE 4. The method is carried out analogously to example 1. The process is carried out at a ratio of:

halon:O2=7 l/h:0.7 l/h, -

when the pressure P=205 PA at a speed of 35 nm/min

EXAMPLE 5. The method is carried out analogously to example 1. The process is carried out at a ratio of:

halon:O2=7 l/h:0.6 l/h, -

when the pressure P=205 PA at a speed of 35 nm/min

Thus, the proposed method allows to obtain a smooth profile at the plasma-chemical etching of the film of silicon nitride with high speed and reproducibility of the process.

Sources of information

1. Technology VLSI // Under the editorship of S. 3i. - M.: Mir, 1986, p.23-41.

The method of plasma-chemical etching of the film of silicon nitride, comprising etching films of silicon nitride from the gas mixture, which consists of the halon oxygen (halon-O2), characterized in that the substrate is subjected to plasma treatment with a gas mixture of refrigerant and oxygen in the following ratio of components:
halon: O2=7 l/h: 0.6 l/h
when the pressure P=205 PA and the speed of 355 nm/min



 

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