Semiconductor device with electrostatic discharge protection diode and manufacturing method thereof

Abstract

The invention discloses a semiconductor device with a static discharging protecting diode and a manufacturing method thereof. The manufacturing method comprises the steps of S1, performing oxidation on partial area of an epitaxial layer of a semiconductor device substrate, and forming a field oxidation area; S2, etching the field oxidation area so that the upper surface of the epitaxial layer in the field oxidation area is lower than the upper surface of a non-field-oxidation area; S3, depositing a polysilicon layer on a first oxidation layer and a field oxidation layer; S4, etching the polysilicon, forming a static discharging polysilicon in the field oxidation area and a gate polysilicon in the non-field-oxidation area, and furthermore keeping the upper surface of the static discharging polysilicon lower than the upper surface of the gate polysilicon; S5, depositing a second oxidation layer on the upper surface of the structure generated in the step S4; S6, grinding the second oxidation layer for exposing the upper surface of the gate polysilicon; and S7, depositing titanium and generating a titanium-silicon alloy. The manufacturing method of the invention can realize effects of ensuring normal operation of a diode and reducing gate resistance.

Description

technical field [0001] The invention specifically relates to a semiconductor device with an electrostatic discharge protection diode and a manufacturing method thereof. Background technique [0002] RF power devices LDMOS (Lateral Double Diffused Metal Oxide Semiconductor) are often used in mobile phone base stations, broadcast television and radar and other fields. Due to the radio frequency characteristics, unlike other power MOS tubes, the radio frequency power device LDMOS has extremely high requirements on the gate resistance, and the gate resistance is as small as possible. Therefore, the gate low resistance process must be used to reduce the gate resistance. Generally, lower gate resistance is achieved by forming a metal silicide on the gate. [0003] In order to ensure reliable operation, an electrostatic discharge (Electro-Static Discharge, ESD) protection diode will be integrated on the RF power device LDMOS. Usually, the ESD protection diode is made on polysilic...

AI Technical Summary

Problems solved by technology

At present, when using the chemical mechanical polishing (CMP) method, there will be such a problem: the gate polysilicon of the RF power device LDMOS and the polysilicon of the ESD protection diode are simultaneously formed on the metal silicide

Metal silicide on ESD polysilicon will cause ESD short circuit and lose the ESD protection of the device

[0014] To sum up, on the one hand, metal silicides need to be formed on the polysilicon of the LDMOS gate of the RF power device; on the other hand, metal silicides cannot be formed on the polysilicon for making ESD protection diodes. Therefore, the above two aspects form a contradiction

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