Method for manufacturing gate oxide

Abstract

The invention provides a method for manufacturing a gate oxide. The method comprises the following steps: providing a semiconductor substrate containing a first region and a second region, and forming a first gate oxide which is 10 to 100 angstroms thicker than the preset thickness on the semiconductor substrate; forming a photoresist layer on the first gate oxide of the first region, and removing part of the first gate oxide on the semiconductor substrate of the second region by using the photoresist layer as a mask and adopting a wet etching reagent with the pH value of 2-8 to ensure that the thickness of the etched residual first oxide of the second region is within a range of 10-20 angstroms; removing the photoresist layer; removing the residual first gate oxide of the second region by adopting the wet etching reagent with the pH value of 2-6; and forming a second gate oxide on the first region of the semiconductor region.

Description

technical field [0001] The invention relates to a manufacturing process of a semiconductor device, in particular to a method for manufacturing a gate oxide layer. Background technique [0002] With the rapid development of semiconductor manufacturing technology, in order to achieve faster computing speed, larger data storage capacity and more functions, semiconductor chips are developing towards higher device density and high integration. A semiconductor device generally includes a core device as a memory and a peripheral circuit as a logic device, and its manufacturing method is as follows. First, a semiconductor substrate is provided, and the semiconductor substrate includes a first region and a second region, wherein the first region It is usually used to form the gate oxide layer of the logic device area, and the second area is usually used to form the gate oxide layer of the memory cell area. Because the operating voltage of the logic device area is high, the thickness ...

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Problems solved by technology

[0004] In the process of removing the first gate oxide layer 102 in the second region by a wet process, the etchant of the wet etching process includes ammonium fluoride and hydrofluoric acid, and its pH value ranges from 2 to 8, preferably 6. to 8, this is because the use of the etchant can have a larger process window to prevent the photoresist layer 103 from peeling off during the wet etching process, but the etchant will cause Increased surface roughness of semiconductor substrates, resulting in product reliability issues

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