Method and device for manufacturing trench MOSFET based on laser

Abstract

The invention discloses a method and device for manufacturing a trench MOSFET based on laser, and belongs to the field of semiconductors. The method solves the problem that three groups of lasers are adopted to prepare grooves and square pits after an epitaxial layer surface is formed on a semiconductor substrate, the-x-direction laser and the-y-direction laser are adopted, exit ports of the-x-direction laser and the-y-direction laser are located at the focal point of convex lens, and after passing through the convex lens, the-x-direction laser and the-y-direction laser are emitted to the lead diaphragm in a parallel light mode and irradiate the surface of the epitaxial layer to form a series of grooves which are perpendicular to one another and are arranged at equal intervals, two-dimensional square matrix bulges are formed among the grooves, the-z direction laser is adopted to irradiate the bulges through the convex lens and a lead template to form two-dimensional array square pits, and another conductive type semiconductor is injected into the square pits, a control gate electrode and a shield gate electrode are formed by using the polycrystalline silicon deposited in the grooves and the oxide on the side surfaces of the epitaxial layer through an etching method, and finally a metal source electrode is formed on the surface of the epitaxial layer and a metal drain electrode is formed on the surface of the semiconductor substrate.

Description

technical field [0001] The invention belongs to a device integrating optics, mechanics and electricity. Lasers are used to prepare grooves on the epitaxial layer of silicon substrates to increase the surface area, increase the density of conductive channels, and reduce the resistance of trench MOSFETs. Fabrication of high-voltage MOSFETs. Background technique [0002] MOSFET, the acronym for Metal Oxide Semiconductor Field Effect Transistor, translates into Chinese as metal-oxide-semiconductor field effect transistor, and its function is to play the role of low-voltage conduction and high-voltage regulation in the circuit. The voltage regulation value of MOSFET is as small as a few volts and as large as thousands of volts. Its functions are different, and its preparation process and preparation method are also different. For MOSFETs that require hundreds of volts to thousands of volts for voltage regulation, MOSFETs are usually prepared by trench method. MOSFET includes so...

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Problems solved by technology

The patent (application number: 201811607412.6, publication number: CN111384168A) discloses that a plurality of grooves are prepared on the surface of the N-type semiconductor epitaxial layer of the substrate in the vertical direction, and square pits are prepared in the center of the protrusion between the grooves to Increase the surface area, increase the density of the conductive channel, reduce the channel resistance of the trench, and reduce the specific on-resistance of the trench MOSFET, but it does not show how to prepare the trench, square pit, and the use of the square

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