The removal method of the pmos replacement gate of the cmos tube

Abstract

The invention discloses a method of removing a PMOS replacement gate of a CMOS transistor. The STI structure on a semiconductor substrate is used as a boundary to form a first area in the PMOS structure and a second area in the NMOS structure; an etching termination layer and an interlayer dielectric layer are sequentially deposited on the surface of the areas; the interlayer dielectric layer is subjected to chemical mechanical polishing which is performed until the etching termination layer, and replacement gates of the PMOS structure and NMOS structure are exposed; a hard mask layer is deposited; the second area is blocked with a photoresist layer, and the hard mask layer on the surface of the PMOS structure is opened to expose the PMOS replacement gate; the photoresist layer is removed by two steps; in the first step, the photoresist layer is treated with oxygen-bearing gas; in the second step, the residual photoresist layer is removed with nitrogen or the combination of nitrogen and hydrogen; the PMOS replacement gate is removed from the buried interlayer dielectric layer. The method has the advantages that polymers are avoided generating during the removal process of the PMOS replacement gate.

Description

technical field [0001] The invention relates to the manufacturing technology of semiconductor devices, in particular to a method for removing a PMOS replacement gate of a CMOS transistor. Background technique [0002] At present, in the manufacturing process of semiconductor devices, P-type metal-oxide-semiconductor (PMOS) transistors, NMOS transistors, or complementary metal-oxide-semiconductor (Complementary Metal-Oxide-Semiconductor, CMOS) composed of PMOS transistors and NMOS transistors Tubes become the basic devices that make up chips. [0003] In order to control the short channel effect, smaller device size requires a further increase in the gate electrode capacitance. This can be achieved by continuously reducing the thickness of the gate oxide layer, but this is accompanied by an increase in gate electrode leakage current. When silicon dioxide is used as the gate oxide layer and the thickness is below 5.0nm, the leakage current becomes unbearable. The way to sol...

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Problems solved by technology

[0012] from Figure 1d It can be seen that during the process of removing the PMOS replacement gate, there is still photoresist. Since the removal of the PMOS replacement gate is performed by dry etching, part of the photoresist will also be lost, resulting in a large amount of polymer that adheres to the PMOS replacement gate. The position of the gate makes it impossible to completely clear the PMOS replacement gate, which means that this will cause Figure 1d The position where the PMOS replacement gate is removed is not a vertical trench, but has a certain slope. The entire trench is in the shape of a narrow top and a wide bottom, so that it is not easy to fill the PMOS metal gate electrode in the trench with this shape later. Material

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