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Neutral ion beam etching technique for plasma surface processor

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Published on:

30 Nov,2020

Neutral ion beam etching technique for plasma surface processor:

 

When the characteristic dimensions of LsI are reduced to less than 7nm, the inherent defects of plasma etching in conventional PLASMA surface processors will limit their further development and applications, such as charge accumulation and deep ultraviolet photon (VUV) radiation. The accumulation of charge caused by electron masking effect will lead to the accumulation of too much positive charge at the bottom of the etching pattern, resulting in charge-induced damage and the reduction of etching accuracy caused by the distortion surface of positive ion orbit. Deep ultraviolet photonic radiation not only intensifies the accumulation of positive charge, but also forms defects on the surface of etched substrate, thus affecting the etching reaction process of the surface. Therefore, it will increase the surface roughness of the substrate and the amount of etching on the side wall, and reduce the precision of etching. In addition, in order to accurately control the surface reaction in the etching process of plasma surface processor, the reaction particles involved in the etching need to have low energy, so as to improve the controllability and precision of the whole etching process.

 

In order to eliminate the above problems in the traditional plasma etching and plasma etching process provides low energy particle surface processor, neutral particle beam etching technique has been developed and obtained a certain development, with the traditional pulse plasma etching and plasma etching and atomic layer etching system, plasma surface treatment machine neutral particle beam etching technology development suited to its own system. So far, the neutral particle beam etching system is mainly divided into three types: electron cyclotron resonance plasma, DC plasma and inductively coupled plasma plus parallel carbon plate. For the electron cyclotron resonance plasmas and dc plasmas, the neutral particle beam is formed by the charge transfer of positive ions, with low neutralization efficiency (about 60%), while the particle beam has high energy (>100eV). This low neutralization flux and high-energy particles, leading to the low, etching etching rate and selectivity, so it is not suitable for etching process is different from the former two ways, the plasma surface treatment machine parallel carbon plates with inductive coupling plasma way, neutral particle beam is formed by anion separation electronics.

 

In the power shutdown stage of plasma pulse technology, a large number of negative ions are generated and pass through parallel carbon plates to form neutral particle beams by separating electrons. Compared with the positive ions, when by parallel plate carbon anion is more likely to be neutral, mainly because of negative ion separation electron energy is much less than positive ion charge transfer, so the neutralization efficiency is much better than the cation, anion chlorine anion neutralization efficiency can be close to one hundred percent, for example, while the neutralization efficiency of chloride ions is only about 60%. In addition, for the inductively coupled plasmas with parallel carbon plates, the bias is applied to the bottom parallel carbon plates, so the negative ion beam energy can be accurately controlled to produce the neutral particle beam with low energy and high flux. Compared with the former two methods, the neutral particle beam etching technique of plasmas coupled by induction and parallel carbon plate has a better application prospect.

 

As the chip feature size is gradually reduced, the requirement of etching process will be higher and higher. When the feature size is reduced to less than 7nm, the need for accurately controlled anisotropic etching process becomes increasingly urgent. The neutral particle beam etching plasma surface treatment machine basic won't produce charge accumulation and ultraviolet photons (vacuum) radiation, and the resulting particle reaction energy is very low, so it is possible that plasma surface treatment machine will be very suitable for 7 nm below fins fet etching of silicon substrate, and under 5 nm carbon nanotubes or graphene devices accurate noninvasive etching.

plasma surface processor

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