Metal layer forming method

Abstract

The invention provides a method for forming a metal layer, which comprises the following steps of: providing a semiconductor substrate on which a dielectric layer and a contact hole penetrating through the dielectric layer are formed; depositing a barrier layer on the surface of the dielectric layer; depositing metal on the surface of the barrier layer, wherein the metal fills the contact hole; grinding until the dielectric layer is exposed, and forming a contact hole plug; sequentially depositing a dielectric barrier layer, an interlayer dielectric layer, an anti-reflection layer and a mask layer above the semiconductor substrate, and etching to form a groove exposing the upper surface of the contact hole plug; a hydrofluoric acid solution is used for cleaning and removing etching residues; cleaning with water to remove residual hydrofluoric acid solution; and filling metal in the groove to form a metal layer which is electrically contacted with the contact hole plug. According to the method, the DHF cleaning solvent is adopted to replace EKC to serve as a wet cleaning solution to clean and remove the etching residues, the open circuit defect of the bottom of the contact hole plug is avoided, and the device product yield is improved.

Description

technical field [0001] The invention relates to the technical field of semiconductor manufacturing, in particular to a method for forming a metal layer. Background technique [0002] At present, in the fabrication process of semiconductor devices, contact holes (CTs) play an important role in the composition of device structures as interconnections between multi-layer metal layers and channels for connection between active regions of devices and external circuits. With the continuous improvement of semiconductor technology, the size of the contact hole is continuously reduced, the size of the contact hole required by the manufacturing process is also reduced accordingly, and the difficulty of manufacturing the contact hole is also increased accordingly. [0003] figure 1 Shown is a flow chart of a method of forming a conventional contact hole. like figure 1 As shown, the existing method for forming a contact hole includes: forming a contact hole 12 in a dielectric layer 1...

AI Technical Summary

Problems solved by technology

This phenomenon leads to the existence of voids 17 in the contact hole plugs 15 formed by the subsequent deposition of metal tungsten.

[0004] Voids 17 can result in back-end processes (BEOL) of semiconductor device fabrication, such as Image 6 As shown, in the process of forming a metal layer by etching above the contact hole plug 15, the EKC solution is introduced into the bottom of the contact hole 12 due to the use of EKC solution to clean and remove the etching residue. EKC has a high corrosion rate for tungsten and will corrode The bottom of the contact hole plug 15, the formed contact hole plug 15 produces an open circuit defect (open defect), such as Image 6 As shown in 18, this will seriously affect the performance and yield of semiconductor devices

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