Pressure sensor and making method thereof

Abstract

The invention provides a pressure sensor and a making method thereof. The making method comprises the following steps: providing a device substrate; sequentially forming an isolation layer and a device layer on the first surface of the device substrate; forming an etch pit with a vertical side wall on the second surface of the device substrate by adopting a plasma etching process until reaching the isolation layer; and bonding the device substrate together with a support substrate by using the second surface as a bonding surface. The making method has the advantages that the back surface etch pit is made through etching by adopting a dry process, the area of the chip made by adopting the method is reduced by 50 percent compared with that made by adopting a KOH or TMAH (tetramethylammonium hydroxide) back-etching process, and a self-stopping process can be realized without adopting an SOI (Silicon On Insulator) substrate, and thus the cost is greatly saved.

Description

technical field [0001] The invention relates to the field of micro-electromechanical systems, in particular to a method for manufacturing a pressure sensor and the pressure sensor. Background technique [0002] MEMS pressure sensors usually use single crystal silicon thin films as sensitive components. In the design, the thickness of the single crystal silicon film needs to be determined according to the measuring range of the product. The smaller the measuring range, the thinner the thickness of the top layer of silicon, which makes the manufacturing process of the pressure sensor in the small measuring range very difficult to control. [0003] SOI material is a common substrate material for making MEMS pressure sensors. The top layer silicon of SOI material can be more easily formed into a thin single crystal silicon film than the traditional bulk silicon substrate material. However, the use of SOI substrates requires the use of KOH or TMAH backside etching to carve out p...

AI Technical Summary

Problems solved by technology

However, the use of SOI substrates requires the use of KOH or TMAH backside etching to carve out pressure chambers. Since the etching pits formed by wet etching have 45-degree inclined sidewalls, this will result in a larger chip size, while SOI substrates The cost of the silicon substrate is much higher than that of the bulk silicon substrate, and the increase in the chip area further increases the manufacturing cost

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