Method for effectively reducing water mark defects

Abstract

The invention discloses a method for effectively reducing water mark defects, which is used for the cleaning process in the process that wafers form double polysilicon gates. After the wafer annealing, the cleaning process is firstly carried out before the tungsten metal silicide deposition. The method is characterized in that the cleaning process comprises the following steps that: the wafers are fed into a wet type etching cleaning system; the wafers are etched in a wet process for removing organic matters and microparticles, and then, the wafers are subjected to drying treatment so that the wafer surface is the hydrophilic surface for reducing the water mark defect formation; and an oxidation layer of the crystal surface is removed through the dry process etching , and the water mark residue is avoided.

Description

technical field [0001] The invention relates to the field of semiconductor wafer etching, in particular to a method for effectively reducing water mark defects. Background technique [0002] Some storage devices need to apply Dual Poly Gate (Double Polysilicon Gate) process. In the prior art, B ion implantation is used to form P-type Poly first, and then P ion implantation is used to form N-type Poly. Then refer to figure 1 , after completing the above steps of ion implantation, perform step S210: annealing (annealing here refers to Post-Implant Anneal, abbreviated as PIA), and then perform step S211: cleaning process (Clean Split), wherein, step S211 is generally performed in wet etching The cleaning system (WET bench) is carried out on the machine, and the end is treated with etching buffer solution or hydrofluoric acid. Next, step S212 is performed: tungsten metal silicide deposition (WSix deposition). Since the Dual Poly Gate (dual polysilicon gate) manufacturing proce...

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Problems solved by technology

[0003] For the above-mentioned steps, the defect of the existing Dual Poly Gate process technology is that since the N-type and P-type Poly are treated with etching buffer or hydrofluoric acid, the degree of hydrophobicity on the surface is different, and the subsequent drying process is easy to Formation of regional water mark defects

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