In order to clarify the formation mechanism of etching residues, the effects of different gas mixtures such as chlorine/helium-oxygen, hydrogen bromide/helium-oxygen and hydrogen bromide/chloride were studied, and we found that in the presence of oxygen, the etching residues form

To clarify the formation mechanism of etch residues, the influence of different gas mixtures such as chlorine/helium-oxygen, hydrogen bromide/helium-oxygen and hydrogen bromide/chloride were studied. We found that in the presence of oxygen, the etch residues formed well, which indicated that the etch residues were caused by the reaction of oxygen and non-volatile silicon halide compounds. The wet cleaning and dry etching cleaning processes were used to remove polysilicon etch residues, which may affect electrical characteristics and further device processes. XPS results show that wet cleaning is suitable for the removal of etch residues.

After using HBr/Cl/He-O2 reaction gas to perform reactive ion etching on polycrystalline silicon, X-ray photoelectron spectroscopy (XPS) and electron microscope (SEM) were used to study the cup-shaped flow layer formed on the surface. In order to find out the formation mechanism of etching residues, the reaction gas of one component was eliminated from the original mixed gas components, and the effect was observed. At the same time, in order to eliminate the residual layer formed after cooling with HBr/CI/He-O2 mixed gas, a wet method and a dry process were introduced for comparison.

Figure 1 is a graph of the experimental sequence. First, on a (100) p-type silicon wafer substrate with a thickness of about 100 nm, polysilicon was grown for about 550 nm by LPCVD method. Then, the prepared substrate was patterned using a 64 MDRAM S1 mask, and then an etching experiment was performed. The etching condition was that the RF power was 150 w, the pressure of the reaction Burger King was maintained at 100 mTorr, and the magnetic field was maintained at 75 Gauss. Under this condition, the etching rate was about 200 nm/min. In order to find out the formation mechanism of the etching residue, one of the components in the original reaction gas component was excluded, and further experiments were conducted. At this time, the mixed gases were chlorine/helium-oxygen (30/9 sccm), hydrogen bromide/helium-oxygen (30/9 sccm), and hydrogen bromide/chlorine. The etching conditions were as above. The residual layer formed after reactive ion etching will affect the post-treatment process. Therefore, in order to eliminate the residual film formed after etching with HBr/Cl/He-O2 mixed gas, wet and dry processes are used.

Figure 2 Etching using HBr/Cl/He-O:reactive gas This is an SEM photo of the observation section. After removing it with O2 plasma and O/H2SO4 solution, the surface of the food was observed and it was found that the residue remained on the polycrystalline silicon film in the form of a capsule. The constituent elements and chemical binding state of the residue formed in this way were investigated. In order to get up, XPS analysis was performed. First, the XPS survey spectrum in Figure 3(a) shows that the components of the residue include silicon, oxygen, carbon in the atmosphere, etc.

To confirm the chemical bond state for each year separation in differentiation, changes along the take-off angle were observed. (B) and (C) of Figure 3 show how the peak intensity of each chemical bond state changes relative to the change of takc-off anglc). Using the etching process, the results showed that the residue exists on the top of the polycrystalline silicon in the form of silicon oxide. In order to find out the formation mechanism of the etching residue, each of which was excluded under the conditions of the original HBr/CI/Hc-O2 mixed gas, experiments were conducted. To reiterate that the chemical bond states of the highest binding energy Si2p and the 535.8 cV of O1s are caused by the etching residue, the depth profilc was analyzed using Ar'. As a result, after 20 minutes of sprinting, it was considered an etching residue, and it can be observed that it occurs rarely.

From the above results, it can be seen that in the post-treatment process of removing residues after reactive continuous etching using HBr/C/He-O and reaction gas, in order to make the surface cleaner, the wet process is more suitable than dry ball information. observes the formation of fluid through the results of x-ray photoelectron energy spectrum (XPS). Therefore, in order to obtain a cleaner surface, wet process can be concluded that the wet process is more appropriate than the dry process.