Preparation method of electronic grade tetraethoxysilane

Abstract

The invention relates to a preparation method of electronic grade tetraethoxysilane and particularly relates to a preparation method of electronic grade tetraethoxysilane for chemical vapor deposition in semiconductor industry. The preparation method comprises the steps of firstly complexing most of metal impurities in raw materials by using a complexing agent, and then filtering by using a microporous filter of 0.1 micron; passing through a cation exchange tower, a quartz plate type distillation tower and a sub-boiling distiller, strictly controlling temperature, and removing trace metal impurities, ethanol, other organic impurities and water. The preparation method provided by the invention adopts conventional purification equipment and has the advantages of convenience in operation, effect of being conductive to industrial large-scale production and low product cost.

Description

technical field [0001] The invention relates to a preparation method of electronic grade tetraethyl orthosilicate, in particular to a preparation method of electronic grade tetraethyl orthosilicate used for chemical vapor deposition in the semiconductor industry. Background technique [0002] In the manufacture of semiconductor electronic components, the components must be encapsulated in glass, or glass is used as an interlayer insulating layer. Typically, the glass layer is SiO2 deposited on the wafer surface by chemical vapor deposition (CVD). 2 layer. [0003] At first, highly toxic and flammable silane was used as the source of vapor deposition. With the upgrading of electronic materials and technology, people pay more attention to its non-toxic, green and environment-friendly characteristics while pursuing high performance of the product. Compared with silane, the toxicity of tetraethyl orthosilicate is greatly reduced, and it is liquid at room temperature, so the op...

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Problems solved by technology

[0004] The content of industrial tetraethyl orthosilicate can reach 99% after general preparation, but it still contains up to 1% of impurities. Among them, metal ions are electrically active impurities, which will reduce the SiO deposited on semiconductor devices. 2 The insulation performance of the thin film layer will cause the micron-scale circuits to be connected to each other, resulting in the scrapping of the circuit board; the non-electrically active impurities such as water and organic matter will affect the uniformity and flatness of the deposited film layer

[0005] U.S. Patent No. 5,840,953 uses gas chromatography to prepare tetraethyl orthosilicate, and removes water impurities with lithium hydride, and the obtained product (in terms of metal impurities) has a purity of not less than 99.999999% tetraethyl orthosilicate, and the moisture content is less than 2PPM, because the gas chromatograph is mainly used for the analysis and detection of trace elements, and the gas chromatograph equipment is expensive, which increases the production cost

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