Method for forming multiple silicon trenches on MEMS (Micro Electro Mechanical Systems) sealing-cap silicon chip and etching mask structure thereof

Abstract

The invention provides a method for forming multiple silicon trenches on an MEMS sealing-cap silicon chip and an etching mask structure thereof. The method comprises the following steps of: Step 11, providing an MEMS sealing-cap silicon substrate; Step 12, forming n superposed mask layers on the MEMS sealing-cap silicon substrate, and after each mask layer is formed, photoetching and etching the mask layer and all the mask layers below the mask layer to form multiple different etching windows; Step 13, with the current uppermost mask layer and the mask material on the next layer as the mask, etching the MEMS sealing-cap silicon substrate; Step 14, removing the current uppermost mask layer; and Step 15, repeating Step 13 and Step 14 till all the mask layers are removed. According to the method for forming multiple silicon trenches on the MEMS sealing-cap silicon chip, multiple trenches with a high aspect ratio can be formed on the MEMS sealing-cap silicon chip by a conventional semiconductor process, and the problem that photoresist cannot be used for the conventional coating on a sealing-cap silicon chip with trenches is solved. The method for forming multiple silicon trenches on the MEMS sealing-cap silicon chip has high industrial applicability.

Description

Technical field [0001] The invention relates to a method for forming multiple silicon grooves of a MEMS cap silicon wafer and an etching mask structure thereof, in particular to a method for forming a plurality of silicon grooves with different groove depths on a MEMS cap silicon wafer. Background technique [0002] Micro Electro Mechanical Systems (MEMS) technology is known as a revolutionary high-tech in the 21st century. Its development began in the 1960s. It is an ingenious combination of microelectronics and micromechanics. It has been developed in recent years. A new type of interdisciplinary technology that will have a revolutionary impact on human life in the future. [0003] The basic technologies of MEMS mainly include silicon anisotropic etching technology, silicon / silicon bonding technology, surface micromechanical technology, LIGA technology, etc. The above-mentioned technologies have become essential core technologies for the development and production of MEMS. In th...

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Problems solved by technology

However, when the aspect ratio of the silicon groove is greater than 2 or the groove depth is greater than 3um, the previously formed deep groove will cause the subsequently formed photoresist to be trapped in the deep groove, resulting in the inability to obtain the silicon wafer by using the conventional coating process. Uniform glue thickness plane, so that the subsequent photolithography process cannot be carried out normally

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