Manufacturing method for IGBT chip with composite grid

Abstract

The invention discloses a manufacturing method for an IGBT chip with a composite grid. The method comprises the following steps: forming a first oxide layer on wafer substrate; etching a first presetposition on the first oxide layer and the wafer substrate corresponding to the lower portion of the first preset position to form a groove; re-etching to remove the first oxide layer, and forming a second oxide layer on the surface of the wafer substrate and on the inner surface of the groove; filling the groove with polysilicon, forming a polysilicon layer on the second oxide layer, and forming apolysilicon body through connecting polysilicon with the polysilicon layer in the groove into one body; and etching a third preset position on the polysilicon layer to enable the polysilicon body tobe divided into a plane grid and a groove grid with an auxiliary grid. The IGBT chip with the composite grid manufactured by the manufacturing method not only has the advantages of good voltage resistance of flat grids, but also is the advantageous in that the groove grid increases the cell density, thus greatly increasing the electric current density of the chip.

Description

technical field [0001] The invention relates to the technical field of semiconductor devices, in particular to a method for manufacturing an IGBT chip with a composite gate. Background technique [0002] Insulated gate bipolar transistor (IGBT) is a compound fully controlled voltage-driven power semiconductor device composed of bipolar transistor (BJT) and insulated gate field effect transistor (MOSFET). Due to its on-state voltage drop, the current With the characteristics of high density, high input impedance and fast response, it is widely used in rail transit, smart grid, industrial frequency conversion and new energy development and other fields. [0003] The gates of existing insulated gate bipolar transistors (IGBTs) are usually planar gates or trench gates. When the gate of the insulated gate bipolar transistor (IGBT) is a planar gate, the manufacturing process of the insulated gate bipolar transistor (IGBT) is simple, the requirements for the manufacturing equipmen...

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Problems solved by technology

[0005] The technical problem to be solved by the present invention is that the insulated gate bipolar transistor chip made by the prior art cannot ensure a large withstand voltage capability and a wide safe working area while greatly increasing the current density of the chip

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