The etching process of the plasma etching equipment changes the morphology principle of the silicon nitride layer:
Plasma etching equipment can achieve functions such as surface cleaning, surface activation, surface etching, and surface coating. Depending on the material to be processed, different processing effects can be achieved. The plasma etching equipment used in the semiconductor industry mainly includes plasma etching, development, glue removal, and packaging. In semiconductor integrated circuits, the etching process of the vacuum plasma cleaner can etch both the photoresist on the surface layer and the silicon nitride layer on the bottom layer. By adjusting some parameters, a certain amount of nitride can be formed. The topography of the silicon layer, that is, the etch slope of the sidewall.
1. Characteristics of silicon nitride material:
Silicate nitride is a new type of hot material. It has the advantages of low density, high hardness, high elastic modulus and good thermal stability, and has been widely used in many fields. Silicon nitride can be used instead of silicon oxide in wafer manufacturing because of its high hardness and can form a very thin silicon nitride film on the surface of the wafer (in silicon wafer manufacturing, the commonly used unit to describe the film thickness is angstroms) , The thickness is about tens of angstroms, which can protect the surface and avoid scratches. In addition, its outstanding insulation strength and oxidation resistance can also achieve a good isolation effect. Its shortcomings are that the fluidity is not as good as that of oxides, and the etching is difficult. The use of plasma etching equipment technology can overcome the etching difficulties.

2. The principle and application of plasma etching:
Plasma corrosion is achieved through chemical or physical action, or the combined action of physics and chemistry. The glow discharge of the gas in the reaction chamber, including the plasma of active substances such as ions, electrons and free radicals, is adsorbed on the surface of the medium through diffusion and chemically reacts with the atoms on the surface to form volatile substances. Under a certain pressure, high-energy ions also physically bombard and corrode the surface of the medium to remove redeposited reaction products and polymers. The combined effect of physical chemistry and physical chemistry is used to complete the etching of the dielectric layer.
Principle of plasma etching:
Etching is an important link in the wafer manufacturing process, as well as a very important link in the microelectronic IC manufacturing process and the micro-nano manufacturing process. It usually takes the photoresist as a mask after photoresist coating and photolithography development. In the film, unnecessary metal is removed by physical sputtering and chemical action to form the same line shape as the photoresist pattern. Plasma etching equipment is currently the mainstream dry etching method. Because of its fast etching speed and good orientation, it has gradually replaced wet etching.
3. Parameters affecting the etching inclination angle of the silicon nitride sidewall:
In semiconductor integrated circuits, the etching process of vacuum plasma etching equipment can not only etch the photoresist on the surface layer, but also etch the underlying silicon nitride layer, while also preventing etching damage to the silicon substrate , In order to meet a number of technological requirements. Through several experiments and tests, it was found that the change of certain parameters of the vacuum plasma etching equipment not only can meet the above etching requirements, but also can form a certain silicon nitride layer, that is, the sidewalls are slanted.