Papers by Keyword: Alkaline Slurry

Abstract: With low-k dielectric materials taking the place of oxide dielectrics as the primary dielectric materials, the low-k dielectric materials and interconnection Cu metals during Chemical Mechanical Planarization (CMP) is becoming a critical surface quality issue as well. In this study, experiments are carefully designed and conducted to investigate the effects of colloidal silica under compared acidic slurry and self-prepared alkaline slurry on k value of low-k dielectric materials, and in both of the slurry, colloidal silica (20~30nm) was used as polishing abrasive. The results showed that k value of low-k dielectric materials both increased within a similar range (self-prepared alkaline slurry, 3.27~3.33; commercial acidic slurry, 3.26~3.32), however, the results showed a obviously different result from reference’s report.

Abstract: With the microelectronic technology node moves down to 45 nm and beyond, and to reduce the RC delay time, low-k dielectric materials have been used to replace regular dielectric materials. Therefore, the down force of chemical mechanical planarization (CMP) needs to decrease based on the characteristics of low-k materials: low mechanical strength. In this study, the effect of new complex agent on copper dissolution in alkaline slurry for CMP was investigated. Based on the reaction mechanism analysis of Cu in alkaline slurry in CMP, the performance of Cu removal rate and surface roughness condition were discussed. It has been confirmed that Cu1 slurry demonstrates a relatively high removal rate with low down force. And also, by utilizing the Cu1 slurry, good result of Cu surface roughness were obtained.

Abstract: Chemical mechanical polishing (CMP) has been a widely applied process for hard disk substrates with nickel–phosphorous (Ni–P) plated. In this paper, the effects of abrasive and surfactant on the polishing performance of hard disk substrates using prepared colloidal silica-based alkaline slurry were investigated. The experimental results indicate that the material removal rate (MRR) strongly depends on the abrasive concentration and nonionic surfactant have little influence on the material removal rate. Under the testing conditions, smaller SiO₂, moderate SiO₂ concentration and higher surfactant concentration can obtain high surface quality in the prepared slurry. These results have been explained by which the abrasive particles move through the cover layer caused by surfactant adsorption on the disk substrates surface being polished.

Abstract: As the integrated circuits developing, the line-width and space between the metal interconnection are shrinking. This increases the RC time delay. To reduce the RC time delay, the low dielectric constant (low-k) material was introduced in the ICs. For process integration considerations, the impact of electronic characters was investigated. In this paper, both static test and CMP(chemical mechanical polishing) process conditions were executed on the low-k material black diamond (BD) with slurry,which was explored by Hebei University of Technology. The slurry was utilized to evaluate the effect on the dielectric properties of BD films. Electrical analyses have shown dielectric properties of BD films would not be degraded during these processes. The static test was dipping the low–k material (BD)in the slurry for 30s and 2minutes, and the results showed the capacitance changed from 3.01to3.40 when dipping in 30s ,and the value reached 3.71 when dipping 2minutes. The resistance changed from 2.9-2.95 to 3.27-3.33 in 30s,and reached 3.57-3.63 in 2 minutes. The result of CMP process showed that the capacitance of five dots , which were selected on the BD film, changed from 2.94-2.98to 2.99-3.05. The dielectric integrity of low k BD films after CMP process remained at an acceptable region to meet requires of multilevel interconnection.

Abstract: Chemical mechanical polishing (CMP) of Cu pattern wafer based alkaline slurry in GLSI with R(NH₂)_n as complexing agent was investigated. In Cu CMP procedure, it is necessary to minimize the surface dishing and erosion while maintaining good planarity. This requirements are met through the complexing agents. Based on the reaction mechanism analysis of Cu in alkaline slurry with R(NH₂)_n as complexing agent in CMP, the performance of Cu dishing and erosion were discussed. The results showed that the slurry stability can be improved obviously by the addition of R(NH₂)_n as complexing agent, both Cu1 and Cu2 have good dishing and erosion performance. Furthermore, the dishing condition of Cu2 (180-230nm) is better than that of Cu1 (280-370nm), and the erosion condition of Cu2 (230-260nm) is also better than that of Cu1 (450-500nm).

Abstract: Chemical mechanical planarization (CMP) of Cu pattern wafer based alkaline Cu slurry in GLSI was investigated. The performance of Cu removal rate and dishing condition were discussed in this paper. Different formation of alkali CMP slurry (Cu1 and Cu2 slurry) were observed by removal rate experiments and showed that alkaline slurry provided a robust polishing performance on initial removal rate, which Cu1 and Cu2 slurry were higher than that of commercial acidity slurry, and in addition, alkaline slurry also have good ending removal rate both in Cu1 and Cu2 slurry and favorable dishing in Cu2 slurry. Furthermore, the result indicated that Cu alkaline slurry with a complexing agent of R(NH2)n, compared with commercial acidity slurry with a inhibitor of Benzotriazol (BTA), have better application foreground for 45nm nod and more advanced nodes.

Abstract: Chemical mechanical polishing (CMP) is the effective technology which obtains high accuracy surface of hard disk substrate with nickel-phosphorus (Ni-P) coating. The slurry is significant factor in hard disk substrate CMP. Colloidal silica-based alkaline slurry was prepared based on negative pressure vortex method. The effects of slurry parameters such as abrasive concentration, organic alkali concentration and oxidant concentration on material removal rate and surface characteristics were investigated. The experimental result indicated that the abrasive concentration was 20wt%, the slurry pH value was 11.2, the oxidant concentration was 15ml/L, improved surface roughness and polishing efficiency of hard disk substrates, a smooth surface was obtained and micro scratches could hardly be observed.

Abstract: Chemical mechanical polishing (CMP) has been a widely applied process for nickel-phosphorus (Ni-P) coating hard disk substrate polishing. In this study, colloidal silica-based alkaline slurry was prepared for polishing Ni-P plated substrates and its CMP mechanism was studied with alkali slurry. Effects of the various process parameters such as polishing pressure and plate speed on hard disk substrate were investigated. The results show that the polishing pressure and plate speed have a strong influence on the material removal rate and surface roughness of the hard disk substrate. The oxidization layer formed on hard disk substrate surface after polishing. The nickel ions were bounded with amidocyanogen to form stable and soluble macromolecular amidocyanogen-complex agent, improved selectivity of convex region and concave region, enhanced the chemical reaction uniformity and the mass transfer velocity, and thus high removal rate and low surface roughness could be realized.

Abstract: Chemical mechanical planarization (CMP) of copper interconnection in hydrogen peroxide (H2O2) as oxidizer based alkaline slurry was investigated. The new model is put forward, which is based on the characteristic of H2O2, chemical kinetics and mechanical removal. This properties of H2O2 can be effectively compensated the defect of surface topology during the process of polishing. Researcher previous study has shown that the surface is largely copper metal with Cu2O at low H2O2 concentrations and largely CuO at high H2O2 concentrations. Cu2O is more easily removed by both chemical and mechanical processes than CuO. During the CMP process, as the oxidizer concentration increases, the removal rate goes up initially followed by a gradual decay. This characteristic of oxidizer is used to achieve copper surface global planarity. The surface planarity was achieved by removing high area on the surface more quickly relative to the low area, because the concentration of Cu2O in the low area as the passivation film is more than the high area. Meanwhile the passivation film of the low area is thicker than the high area. In order to achieve polishing process optimization, the influence of pH adjustment and pressure, are also taken into consideration. Combining both RR and PE, the optimal H2O2 concentration and pressures are in range 1.0 ~1.5 vol% and 0.04 ~0.07 mpa, respectively. The roughness of surface which is measured by AFM is 0.49 after CMP.