Preparation method of power device and power device

Abstract

The invention proposes a power device preparation method and a power device. The method comprises the steps: forming a photoresist layer on an oxidation layer protection layer with a diode and a power unit; removing the photoresist layer on the oxidation layer protection layer of an active region of the power unit, and keeping the photoresist layer on the oxidation layer protection layer of an electrostatic protection region of the diode, so as to complete the preparation of the power device. According to the technical scheme of the invention, the oxidation layer protection layer of the electrostatic protection region of the diode is provided with the photoresist layer, thereby protecting a corner of the oxidation layer protection layer of the electrostatic protection region from being etched in a preparation process of the power device, avoiding the forming of metal silicide on a polycrystalline silicon base layer of the diode, guaranteeing the electrostatic protection function of the diode for the power device, and further guaranteeing the reliability of the power device.

Description

technical field [0001] The invention relates to the technical field of semiconductors, in particular, to a method for preparing a power device and a power device. Background technique [0002] At present, power devices are widely used in radar, radio and television, base stations and other fields. For example, power devices are Radio-Frequency Laterally-Diffused-Metal-Oxide-Semiconductor (RF LDMOS, Radio-Frequency Laterally-Diffused-Metal-Oxide-Semiconductor). In addition, In order to reduce the gate resistance of the power device and increase the frequency, a metal silicide structure layer is usually formed on the silicon gate structure of the power device, and a self-aligned process is usually used to prepare the metal silicide structure layer. Specifically, in the related art, an anti-reflective coating (ARC, Anti-Reflective-Coating) is coated on the oxide layer protection layer of the power device, and the coating at the high position is thinner, and the coating at the l...

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Problems solved by technology

[0003] However, if a diode is integrated in the power device (such as an anti-static protection diode, i.e. an ESD diode, and ESD is Electro-Static Discharge, electrostatic discharge), then the scheme for preparing the power device in the related art will have disadvantages, specifically, due to Diodes are generally made on the same polysilicon base structure as the gate, and metal silicides cannot be formed on the polysilicon base structure of the diode, otherwise the diode will be short-circuited, and the diode will lose its protection function for power devices.

like figure 1 and figure 2 As shown, after the antireflection coating is applied, the polysilicon substrate of the diode is relatively wide, and the antireflection coating on the polysilicon substrate is relatively thick, but at the corners on top of the polysilicon substrate, the antireflection coating is relatively thin, In this way, it is easy to be etched away in the etch back, and then the oxide protective layer at the corner is also etched away, so that in the subsequent process of forming the metal silicide structure layer, the corner of the polysilicon base structure will be formed. Metal silicide, which causes the diode to short out and fail

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