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The replacement metal gate (RMG) defectivity performance control is very challenging in high-k metal gate (HKMG) chemical mechanical polishing (CMP). In this study, three major defect types, including fall-on particles, micro-scratch and corrosion have been investigated. The research studied the effects of polishing pad, pressure, rotating speed, flow rate and post-CMP cleaning on the three kinds of defect, which finally eliminated the defects and achieved good surface morphology. This study will provide an important reference value for the future research of aluminum metal gate CMP.

After the chemical mechanical planarization (CMP) process, the copper surface is contaminated by a mass of particles (e.g.silica) and organic residues (e.g.benzotriazole), which could do great harm to the integrated circuit, so post-CMP cleaning is essential.In particular, benzotriazole (BTA) forms a layer of Cu-BTA film with copper on the surface, which leads to a hydrophobic surface of copper.So an effective cleaning solution is needed to remove BTA from the copper surface.In this work, a new compound cleaning solution is designed to solve two major problems caused by BTA:one is removing BTA and the other is copper surface corrosion that is caused by the cleaning solution.The cleaning solution is formed of alkaline chelating agent (FA/O II type), which is used to remove BTA, and a surfactant (FA/O I type), which is used as a corrosion inhibitor.BTA removal is characterized by contact angle measurements and electrochemical techniques.The inhibiting corrosion ability of the surfactant is also characterized by electrochemical techniques.The proposed compound cleaning solution shows advantages in removing BTA without corroding the copper surface.

The effect of a non-ionic surfactant on particles removal in post-CMP cleaning was investigated. By changing the concentration of the non-ionic surfactant, a series of experiments were performed on the 12 inch Cu pattern wafers in order to determine the best cleaning results. Then the effect of the surfactant on the reduction of defects and the removal of particles was discussed in this paper. What is more, the negative effect of a non-ionic surfactant was also discussed. Based on the experiment results, it is concluded that the non-ionic surfactant could cause good and ill effects at different concentrations in the post-CMP cleaning process. This understanding will serve as a guide to how much surfactant should be added in order to achieve excellent cleaning performance.

We have developed an alkaline barrier slurry (named FA/O slurry) for barrier removal and evaluated its chemical mechanical planarization (CMP) performance through comparison with a commercially developed barrier slurry. The FA/O slurry consists of colloidal silica, which is a complexing and an oxidizing agent, and does not have any inhibitors. It was found that the surface roughness of copper blanket wafers polished by the FA/O slurry was lower than the commercial barrier slurry, demonstrating that it leads to a better surface quality. In addition, the dishing and electrical tests also showed that the patterned wafers have a lower dishing value and sheet resistance as compared to the commercial barrier slurry. By comparison, the FA/O slurry demonstrates good planarization performance and can be used for barrier CMP.

This paper presents a new cleaning process using boron-doped diamond (BDD) film anode electrochemical oxidation for metallic contaminants on polished silicon wafer surfaces. The BDD film anode electrochemical oxida- tion can efficiently prepare pyrophosphate peroxide, pyrophosphate peroxide can oxidize organic contaminants, and pyrophosphate peroxide is deoxidized into pyrophosphate. Pyrophosphate, a good complexing agent, can form a metal complex, which is a structure consisting of a copper ion, bonded to a surrounding array of two pyrophosphate anions. Three polished wafers were immersed in the 0.01 mol/L CuSO4 solution for 2 h in order to make comparative exper- iments. The first one was cleaned by pyrophosphate peroxide, the second by RCA (Radio Corporation of America) cleaning, and the third by deionized (DI) water. The XPS measurement result shows that the metallic contaminants on wafers cleaned by the RCA method and by pyrophosphate peroxide is less than the XPS detection limits of 1 ppm. And the wafer's surface cleaned by pyrophosphate peroxide is more efficient in removing organic carbon residues than RCA cleaning. Therefore, BDD film anode electrochemical oxidation can be used for microelectronics cleaning, and it can effectively remove organic contaminants and metallic contaminants in one step. It also achieves energy saving and environmental protection.

This paper presents a new cleaning process for particle and organic contaminants on polished silicon wafer surfaces. It combines a non-ionic surfactant with boron-doped diamond (BDD) film anode electrochemical oxidation. The non-ionic surfactant is used to remove particles on the polished wafer's surface, because it can form a protective film on the surface, which makes particles easy to remove. The effects of particle removal comparative experiments were observed by metallographic microscopy, which showed that the 1% v/v non-ionic surfactant achieved the best result. However, the surfactant film itself belongs to organic contamination, and it eventually needs to be removed. BDD film anode electrochemical oxidation (BDD-EO) is used to remove organic contaminants, because it can efficiently degrade organic matter. Three organic contaminant removal comparative experiments were carried out: the first one used the non-ionic surfactant in the first step and then used BDD-EO, the second one used BDD-EO only, and the last one used RCA cleaning technique. The XPS measurement result shows that the wafer's surface cleaned by BDD-EO has much less organic residue than that cleaned by RCA cleaning technique, and the non-ionic surfactant can be efficiently removed by BDD-EO.