Semiconductor device and manufacturing method thereof

Abstract

According to the semiconductor device and the manufacturing method thereof, after a vertical oxide layer structure is deposited, the upper surface of the vertical oxide layer structure is lowered to be below the upper surface of a semiconductor substrate through etching, and then a horizontal oxide layer structure is obtained through oxidation on the semiconductor substrate and the vertical oxide layer structure according to a local silicon oxidation isolation technology. According to the semiconductor device and the manufacturing method thereof, the upper surface of the vertical oxide layer structure is etched below the upper surface of the semiconductor substrate before the horizontal oxide layer structure is obtained through oxidation, so that the sharp corner structure at the top edge of the groove corresponding to the vertical oxide layer structure can be oxidized from the side surface and the upper surface at the same time during oxidation; the sharp corner structure is smoothed, a smooth junction structure of the horizontal oxide layer structure and the vertical oxide layer structure is obtained, the thickness of the obtained horizontal oxide layer is guaranteed, the breakdown protection performance of the horizontal oxide layer structure is guaranteed, and the performance of the semiconductor device is improved.

Description

technical field [0001] The present invention relates to the field of semiconductor technology, in particular, to a semiconductor device and a manufacturing method thereof. Background technique [0002] The power switch may be a semiconductor device, including a metal-oxide-semiconductor field-effect transistor (Metal-Oxide-Semiconductor Field-Effect Transistor, MOSFET) and an insulated gate bipolar transistor (Insulated Gate Bipolar Transistor, IGBT). Laterally Diffused Metal Oxide Semiconductor (LDMOS) is widely used in switching regulators. [0003] figure 1 shows a schematic structural diagram of an LDMOS device according to the prior art, such as figure 1 As shown, the LDMOS device 100 is provided with a body region 120 and a drift region 130 in a semiconductor substrate 110, a first doped region 121 and a second doped region 122 are arranged in the body region 120, and a drain is arranged in the drift region 130. region 131, a shallow trench isolation (shallow trench...

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Problems solved by technology

[0004] In the LDMOS device 100 of the prior art, a sharp corner 10 is formed at the junction of the field oxide layer 150 and the shallow trench isolation region 140, and the sharp corner 10 will reduce the thickness of the field oxide layer 150 in this part and reduce its breakdown. voltage, and the sharp corner 10 is easy to accumulate charges, which increases the risk of breakdown of the field oxide layer 150 and reduces the performance of the LDMOS device 100

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