Process for cleaning silicon chip by using diluted fluohydric acid

Abstract

The invention discloses a process for cleaning a silicon chip by using diluted fluohydric acid, which comprises the step that the diluted fluohydric acid is used in the step of chemical reagent cleaning, namely the last step of the cleaning flow, wherein the volume ratio (HF to H2O) of the fluohydric acid to water in fluohydric acid cleaning solution is 1:300-1:2,000, and the cleaning time of the diluted fluohydric acid cleaning solution is between 30 and 1,000 seconds. The process has the advantages that the surface of the silicon chip cleaned by the process still is a hydrophilic surface, so adsorption phenomena of particles and part of metals caused by the conventional hydrophobic surface cleaned by DHF do not occur. By using the process, the metal contamination of the surface of the silicon chip after being cleaned by the process is less than 1E10atoms/cm2, and simultaneously the particle contamination degree (more than or equal to 0.10 micron) of the surface of the silicon chip can be less than 15 per piece, so the defects of the conventional cleaning solution in RCA cleaning are further overcome.

Description

technical field [0001] The invention relates to a cleaning process for silicon wafers by using diluted hydrofluoric acid (DHF). Specifically, an ultra-low concentration DHF solution is used to clean silicon wafers to ensure that the metal contamination on the surface of the silicon wafers is removed Under the premise of cleaning, the surface of the silicon wafer after DHF cleaning is still hydrophilic. technical background [0002] At present, most silicon polished wafers used in the manufacture of integrated circuits adopt the technological process of Czochralski, slicing, grinding, etching, polishing, cleaning, and inspection. Among them, cleaning is the last step in the whole process, so the quality of the cleaning effect will be directly reflected on the customer. [0003] At present, the cleaning methods widely used in the silicon wafer manufacturing process are the standard RCA cleaning method and the improved RCA cleaning method. The chemical reagents used in this cl...

AI Technical Summary

Problems solved by technology

HPM is H 2 o 2 , HCL and water mixed acidic solution, which has strong oxidizing and complexing properties, can react with metals before oxygen to form salts, and then be removed with deionized water washing, the oxidized metal ions interact with CL- The generated soluble complexes are also removed with deionized water washing, so it is mainly used to remove metal contamination on the surface of the silicon wafer; due to the SiO on the surface of the wafer 2 Si and Si cannot be corroded, so the effect of removing particles cannot be achieved, but will bring particle contamination

[0004] From the advantages and disadvantages of the above-mentioned various cleaning solutions, it can be seen that no matter which process is used, the perfect cleaning effect cannot be achieved.

For example, the cleaning process used in traditional RCA cleaning is APM→DHF→HPM. HPM can effectively remove metal contamination on the surface of silicon wafers, but the ideal surface particle state cannot be obtained.