Gas backflow prevention device

Abstract

The invention discloses a gas backflow prevention device which is arranged in a reaction cavity of a plasma etching device, a chip base is arranged in the reaction cavity, and the gas backflow prevention device is sleeved outside the chip base. The gas backflow prevention device is characterized in that the gas backflow prevention device is an annular body, a plurality of air channels are arranged on the annular body at intervals, and an upper opening of each air channel is smaller than a lower opening. The air channels can be arranged in the annular body in vertical mode and can be inclinedly arranged in the annular body to form an included angle with the annular body. When the plasma etching device of the gas backflow prevention device is used in the bosch technology and switching of two kinds of gases is performed, the first kind of gas can be prevented from flowing back to the upper space of the reaction cavity from the air channels to be mixed with the second kind of gas, so that the switching spacing interval of the two gases is shortened, scallop-shaped lateral walls can be prevented from forming in the bosch technology, product etching quality is improved, and production efficiency is improved.

Description

technical field [0001] The invention relates to plasma etching equipment, in particular to a gas backflow preventing device for plasma etching equipment. Background technique [0002] At present, in the field of semiconductor manufacturing technology, through-silicon via (TSV) technology has been widely used in the field of three-dimensional packaging. The through-silicon via technology requires deep reactive ion etching on the wafer. In the prior art, deep reactive ion etching is usually performed using a Bosch process. The Bosch process mainly includes the following steps: (1) etching step, usually with SF 6 The mixed gas is used for chemical reactive ion etching; (2) the passivation step of polymer deposition, usually with C 4 h 8 The mixed gas forms a fluorocarbon polymer layer on the inner side of the hole, so that during the chemical reactive ion etching in the etching step of the next cycle, the SF 6 The gas does not etch the sidewall polymer or the etch rate is v...

AI Technical Summary

Problems solved by technology

[0004] The following problems exist in the implementation of the Bosch process using the above-mentioned prior art plasma etching equipment: (1) When etching deep through-silicon holes, the etching step and the deposition passivation step that are repeated and alternately cycled make the through hole deeper and at the same time Also form scalloped undulating side walls

When using the plasma etching equipment of the prior art to implement the Bosch process, because the interval between etching gas and deposition gas switching is reduced, the risk of mixing the two gases in the reaction chamber during the switching process increases. The former The gas is not discharged in time, and the return flow is mixed with the latter input gas, which will cause the etching rate to decrease

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