Research on plasma etching of silicon by plasma plasma treatment:
        In the microelectronics process, the silicon etching process is widely used, such as the production of MEMS for device isolation trenches or vertical capacitors in high-density DRAMICs.
        At present, there are two main methods for etching single crystal silicon: one is the wet method. The wet etching method has some limitations of its own, such as the use of a large number of toxic chemicals, the operation is not safe enough, lateral penetration and due to immersion Swelling leads to poor adhesion and undercutting, which reduces the resolution, which has been gradually replaced by dry etching.

Plasma treatment to etch silicon
        The second method of etching silicon is plasma plasma treatment and plasma dry etching. The traditional plasma etching technology is mainly carried out under the low pressure environment of the vacuum chamber. After years of exploration and improvement, this technology has become more and more perfect. . However, due to the limitation of the vacuum equipment itself, there are not only high equipment and maintenance costs, inconvenient operation and other problems in use, but also the size of the object to be processed is also limited by the vacuum chamber cavity, which is not easy to achieve large-scale industrial production. Whether the material can be etched under normal pressure has become the focus of attention in recent years. In recent years, some new atmospheric pressure radio frequency cold plasma plasma treatment discharge equipment has been developed for use in microelectronic etching process. Atmospheric radio frequency cold plasma spray gun equipment is composed of radio frequency power supply plasma generator air intake system and heating system. The frequency of the radio frequency power supply is 13.56MHz, and the working range is 0~600w.
        The plasma plasma generator is composed of two insulated metal coaxial inner and outer electrodes. The inner electrode is connected to the output terminal of the radio frequency power supply, and the outer electrode is grounded. After proper power is applied, the introduced gas is broken down and ionized between the electrodes to form a cold plasma beam and spray downward uniformly. Choose argon gas and non-corrosive and non-toxic SF6 gas, the diameter of the nozzle is 10mm, and the length of the jet stream is 5-20mm. The length of the beam depends on the size of the discharge power and the size of the air intake. The process of etching single crystal silicon with atmospheric pressure radio frequency cold plasma equipment shows that:
        (1) The etching rate is almost linearly proportional to the input power; the etching rate and the substrate temperature are also basically linearly increasing.
        (2) Plasma has a good selection ratio for shallow etching of silicon, and the etching steps have good uniformity and anisotropy.
        (3) The experiment is carried out under normal pressure, which reduces the damage to the surface of the silicon wafer like vacuum plasma. However, because the operation is under normal pressure, the experiment has problems such as low etching speed and load effect.
        In the future work, we will choose SiO2 or AI as the mask, and add an appropriate amount of O2 during the plasma plasma etching process to increase the etching speed. And further improve the equipment to reduce or even eliminate the existing load effect, in order to obtain a very good etching effect.