Papers by Author: Yan Gang He

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: Indium antimony(InSb) is one of the important materials which can be used to make semiconductor devices such as infrared detection device. Due to the low hardness and great brittleness, the surface scratching always appears and surface roughness is hard to lower during surface preparation. So it should be increasing the InSb surface quality during ultra precision machining. In this paper the InSb surface adsorption-control technology was introduced. Through controlling surface roughness during chemical mechanical polishing(CMP) and using preferential adsorption during cleaning, the adsorptions of InSb surface were controlled. Through experiments, the CMP optimal process parameters under the alkaline conditions were gotten. Under such conditions, the preferable surface state was realized. According to the preferential adsorption model, through using FA/O non-ionic surfactant the polished wafer surface can be kept in physical adsorption and easy cleaning state, so the wafer surface adsorption can be controlled effectively and the clean surface was obtained.

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: Along with the feature size reducing and the increase of integration level rapidly in ULSI，the request for metal impurities contamination on silicon substrate surface appears specially rigorous. In this paper the chelating agent was added in cleaning solution in order to removing copper ion. FA/O, a new kind of chelating agent was studied in RCA cleaning solutions, which has 13 chelating rings and is free of sodium, stable and easily soluble. The XPS and GFAAS measured results indicate that FA/O is more efficient than NH4OH as a ligand. Cu contaminations on silicon wafer can be removed remarkably when adding a little FA/O to the cleaning solution or polishing slurry. When the chelating agent concentration of cleaning solution is 0.1% the removal rate of Cu atom reaches 83 percent. The FA/O chelating agent substituting NH4OH in SC-1 may simplify cleaning steps, and one cleaning step can remove Cu pollution on silicon wafer surface and meet the requirements of microelectronics technology.