Vacuum processing apparatus, vacuum processing method, and micro-machining apparatus

Abstract

Disclosed is a technology in which a nozzle part is mounted in a vacuum chamber and a silicon substrate is held to face a discharge hole of the nozzle part. For example, ClF3 gas and Ar gas are supplied from the nozzle part and the mixed gas is discharged from the nozzle part under a vacuum atmosphere. By doing this, the mixed gas is adiabatically expanded and the Ar atoms or ClF3 molecules are combined, which become a gas cluster. The gas cluster is irradiated to the surface of the silicon substrate without being ionized and, as a result, the surface of the silicon surface becomes a porous state. Then, lithium is grown on the surface of the silicon substrate in a separate vacuum chamber 41 by sputtering without breaking the vacuum.

Description

technical field [0001] The present invention relates to a technique for making the surface of a silicon substrate porous in a vacuum atmosphere. Background technique [0002] In recent years, nano-scale microfabrication of silicon substrates has attracted attention in various fields such as thermosonic devices, solar cells, and biological substrates. As one of them, lithium-ion secondary batteries are currently being studied. Application of negative electrode materials. Carbon has been used conventionally as a negative electrode material for lithium ion secondary batteries. Recently, however, lithium-ion secondary batteries are required to have a higher capacity, and as a negative electrode material to replace carbon, silicon, which can achieve a higher capacity than carbon by an order of magnitude, has attracted attention. [0003] However, silicon has the property of expanding when forming an alloy with lithium ions, so when using silicon as a negative electrode material...

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Problems solved by technology

[0003] However, silicon has the property of expanding when forming an alloy with lithium ions. Therefore, in the case of using silicon as a negative electrode material, it is also necessary to overcome the following durability problems: damage to the battery due to expansion, failure of charging and discharging, etc. Deterioration of the negative electrode due to repeated volume changes, etc.

Thereby, the surface of the silicon substrate is oxidized by moisture and oxygen in the atmosphere, and the adhesion of impurities in the electrolyte or electrode materials, or even impurities in the atmosphere can cause pollution, and it may not be possible to obtain a high level of formation in the subsequent process. Silicon substrate surface cleanliness required for quality lithium films

[0007] Patent Document 1 describes a method of performing nanoscale microfabrication on the surface of a silicon substrate using a laser beam, but does not discuss any of the above-mentioned issues.

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