Metal grid structure and formation method thereof

Abstract

The embodiment of the invention discloses a metal grid formation method. The method comprises the steps of providing a substrate, wherein a grid region to be filled is arranged on the substrate; forming a blocking layer along a surface of the grid region to be filled; filling the region to be filled with a metal medium along a surface of the blocking layer to form an electrode layer; and annealingthe electrode layer so that metal atoms in the electrode layer can be automatically diffused. In the method, the diffusion activation energy of the metal atoms is relatively low, the metal atoms canbe automatically diffused after thermal treatment and can be diffused to holes with relatively high vacancy concentration, and the vacancy concentration can be balanced after the metal atoms are diffused to a certain extent; vacancies of hole positions are mostly occupied by the diffused metal atoms, and the holes are filled macroscopically; from an angle of a crystal, a grain boundary is migratedby migration of the atoms, the grain is grown, and the holes are also reduced; and since the holes are filled, the risk of fluorine residue is reduced, and the risk of fluorine corrosion is further reduced.

Description

technical field [0001] The present application relates to the field of semiconductors, in particular to a metal gate structure and a method for forming the same. Background technique [0002] With the development of information technology, the requirements for the computing speed and integration of semiconductor devices are gradually increased, and the feature size of semiconductor devices is gradually reduced. As a part of the device, the material of the gate greatly affects the performance of the device. Due to the "polysilicon depletion" effect in the traditional polysilicon gate process, which affects the conduction of the device, a metal gate is introduced. [0003] In metal gate technology, tungsten gate is widely used. As the filling aspect ratio becomes higher and higher, the step coverage of the filling process is challenged. During the growth process of metal tungsten, even if an atomic layer deposition (Atomic Layer Deposition, ALD) process is used, voids will ...

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Problems solved by technology

Metal tungsten is generally through tungsten hexafluoride WF 6 with hydrogen H 2 Reduction for deposition, the fluoride in the reaction process may remain in the pores, resulting in a higher fluorine element in the tungsten film, too high a fluorine content will corrode the oxide layer of the device, and then cause device leakage

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