A dust removal device for plasma etching machine

Abstract

The invention relates to the technical field of semiconductor processing, and discloses a dust elimination device for a plasma etching machine, which includes a body, the inner wall of the body is surrounded by ring-shaped grooves, and the grooves are arranged on the inner wall of the body in sequence. The inner wall of the groove is bonded with an adsorption plate. Through the cooperation between the adsorption plate and the reaction gas, when the gas bombards the substrate, it moves downward spirally along the inner wall of the body, causing friction between the gas and the adsorption plate. As the friction increases, the adsorption plate is attached Positive charges, and then use the principle of mutual attraction of positive and negative charges, so that the negatively charged dust particles are directly attracted by the positive charges on the adsorption plate during operation, so that all the dust particles gather on the adsorption plate, and some dust particles are positively and negatively charged When they offset each other, they fall into the slot, and another part of the dust particles fall into the slot when the discharge ends, so that the surface of the substrate remains clean after processing, and the internal cavity is also easy to clean.

Description

technical field [0001] The invention relates to the technical field of semiconductor processing, in particular to a dust removal device for a plasma etching machine. Background technique [0002] Plasma etching machine, also known as plasma etching machine, plasma plane etching machine, plasma etching machine, plasma surface treatment instrument, plasma cleaning system, etc., is mainly used for etching technology of silicon materials. [0003] The working principle of the existing plasma etching machine is as follows Image 6 As shown in the figure, under the vacuum and low pressure, the radio frequency generated by the ICP radio frequency power supply is output to the annular coupling coil, and a certain proportion of mixed etching gas is coupled to the glow discharge to generate high-density plasma. Under the action of the RF radio frequency of the lower electrode, These plasmas bombard the surface of the substrate, the chemical bonds of the semiconductor material in the p...

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Problems solved by technology

[0003] The working principle of the existing plasma etching machine is as follows: Image 6 As shown, under vacuum and low pressure, the radio frequency generated by the ICP radio frequency power supply is output to the ring coupling coil, and a certain proportion of mixed etching gas is coupled with glow discharge to generate high-density plasma. Under the action of RF radio frequency of the lower electrode, These plasmas bombard the surface of the substrate, the chemical bonds of the semiconductor material in the pattern area of ​​the substrate are interrupted, and volatile substances are generated with the etching gas, which are detached from the substrate in the form of gas, drawn away from the vacuum pipeline, and then generated in the gas. The dust particles are sucked away by the fan. The commonly used gases in plasma etching are gases such as argon and silane. The latter is a highly reactive gas, causing the molecules to gather to form dust particles. The dust particles are bombarded downward by the inertial force of the plasma. With gravity, it rotates spirally along the plasma cavity, causing dust particles to bombard the substrate, causing the surface of the substrate to be deformed during processing, the surface is uneven, and the internal circuit is damaged, which affects the normal use of the substrate. At the same time, during plasma processing, The reactive gas polymer in the discharge chamber will absorb the surrounding electrons and carry a certain amount of negative charge to form dust particles (~10^(-8)m), which are suspended, gathered and moved above the processed chip, In addition, compared with the ions and electrons in the plasma, dust particles have larger volume, mass, charge and smaller charge-to-mass ratio. Negatively charged dust particles will be subjected to electric field force and ion drag in the radio frequency sheath. Force, neutral gas friction, and interaction with other dust particles cause the dust particles to become more and more concentrated, and the dust particles cannot be completely removed by the force of the twitch, and the gas is also easily absorbed by the particles during the process of removing the particles. Driven, causing gas leakage, affecting the surrounding environment, and the inner cavity can no longer meet the conditions for the reaction between the substrate and the gas. When the discharge is over, these dust particles will fall on the surface of the chip under the action of gravity and inertial force, resulting in Damage to the semiconductor chip, unusable

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