A method for preparing thick-film silicon nitride region trenching

Abstract

The invention provides a region-digging preparation method of thick-film silicon nitride, comprising: forming a lower cladding layer on a semiconductor substrate along the thickness direction of the semiconductor substrate; photolithography and etching the lower cladding layer, and forming A plurality of core region grooves; depositing core material in the plurality of core region grooves and on the lower cladding layer to form a first core layer, the thickness of the first core layer is less than the thickness of the preset waveguide device region; the lower cladding layer The upper surface is a termination layer, and the redundant first core layer is removed by a surface planarization process; the above steps are repeated until the thickness of the core layer formed in the groove of multiple core layer regions reaches the thickness of the preset waveguide device region; for multiple core layers The layers are respectively etched to form a preset waveguide device structure in each core layer; an upper cladding layer is formed on the preset waveguide device structure and the lower cladding layer. The invention solves the problem of high stress caused by too thick film, is beneficial to realize high integration of chips, and can realize thicker film growth on a large wafer.

Description

technical field [0001] The invention relates to the technical field of integrated optics, in particular to a method for preparing a region-digging groove of thick-film silicon nitride. Background technique [0002] At present, silicon nitride film growth and preparation methods mainly include low-pressure chemical vapor deposition (LPCVD) and plasma chemical vapor deposition (PECVD). Thick film deposition can be achieved by using PECVD, but there are many impurities in the film and the compactness is poor, so the waveguide prepared by it has high transmission loss. However, the silicon nitride film deposited by LPCVD has good quality and low waveguide loss, but there is a problem of high stress, especially when the film thickness is greater than 300 nanometers, it is difficult to achieve large-area growth, and a large number of cracks will appear in the film, which cannot realize high-performance devices. preparation. In the existing production process, the required wavegu...

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Problems solved by technology

[0003] In order to overcome the problem of high stress during the growth of thick film silicon nitride in the prior art, a regional trenching preparation method for thick film silicon nitride is provided, which can solve the problem of high stress caused by too thick film, so as to meet different needs. design needs

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