Papers by Keyword: CMP

Abstract: Based on the hybrid combination of case-based reasoning and BP-neural network, process parameters intellectual decision strategy of function ceramics with high efficiency and precision chemical mechanical polishing (CMP) was proposed in this paper firstly. And then, referring to the technical manuals, experiences of engineering workers and experimental data, the process parameters database for function ceramics in CMP has been built with Microsoft software Access. On the basis of the above efforts, the process parameters intellectual decision support system for high efficiency and precision CMP of function ceramics has been developed by applying PowerBuilder software, which can realize the process parameters optimization, the surface roughness prediction and process parameters intellectual decision. Examples show that the prediction results are coincident with the experiments well.

Abstract: It is of significance to research high-removal efficiency and low-cost CMP process for the 65 nm and below node. Chemical mechanical polishing (CMP) can realize the planarization of the wafer with free defects, free contamination and below nanometer level roughness. Test project of CMP slurry is main contain of these detections such as pH value, chelating agent content, SiO2 gel particle size, ζ-potential detection and the observation by Transmission electron microscopy (TEM). End point detection method of pattern wafer CMP usually includes the non destructive optical measurement, motor current feedback measurement and polishing pad temperature test. The main problems of the measurement for pattern wafer CMP are critical dimension (CD), section, film thickness, defects and particles measurement. Some of the new type of testing technology, such as atomic force profiler (AFP), can be used to compare CMP effect, such as dishing, erosion, tungsten plugs, the height of steps and flatness of the wafer, which is significant for wafer CMP research.

Abstract: CeO₂ nanoparticles were synthesized by homogeneous precipitation in mixed solvent of alcohol and deionized water under microwave radiation using Ce(NO₃)₃•6H₂O and HMT as starting materials. The structure and morphology of the products were characterized by X-ray diffraction (XRD), transmission electron microscopy (TEM), selected-area electron diffraction (SAED), and BET-N₂. The oxide chemical mechanical polishing (CMP) behavior of the as-papered CeO₂ abrasives was investigated by atomic force microscope (AFM). The results indicated that the obtained CeO₂ particles were monodispersed with an average diameter of ca. 10 nm. There was a quite good consistency in the particle sizes from TEM and BET analyses. Polishing tests showed that the as-prepared ceria abrasives exhibited a good oxide CMP performance, which might attribute to the uniform size and shape of the as-prepared CeO₂ particles. In addition, the polishing pressure had an obvious influence on the surface topography, profilogram and roughness.

Abstract: Characterization of the surface morphology after CMP vital refers to the roughness of surface outline at present. The two dimensional parameters characterization based on scanning the outline of surface as the test foundation already cannot satisfy the requirements of engineering; hence three dimensional detection and quantitative calculation of surface morphology can complete characterization. Characterization of surface morphology has made great development from low to high precision accuracy, from a single variety of touch probe to optical, atomic force, and other varieties, from the contact to non-contact, from two dimensions to three dimensions, from a single roughness measurement to simultaneously measurement of waviness, shape error outline information. Scanning probe microscopy can give surface topography of the whole measured area. Because discrimination all can reach the nanometer level surface roughness in x, y and z three directions, Scanning probe microscopy is suitable for measured structure with vertical structure units in nm magnitude and horizontal area in μm scale.

Abstract: Reported in this paper is an investigation of the process parameter effects on surface roughness and subsurface damage (SSD) in CMP of single crystalline Silicon. For the given experiments, the appropriate method to examine the SSD can be obtained. The surface roughness and figure accuracy were measured with an atomic force microscope (AFM) and Taylor-Hobson profilometer. The experiments results indicate proper process parameter for the best surface roughness, which can be divided into two stages. It should use longer time in the finish polishing stage, while shorter time and reduce the ratio of polishing pads and head in the ultra-finish polishing stage. Generally speaking, the isotropic etching of single crystalline Silicon, anisotropic etching of single crystalline Silicon and hand burnishing are mostly used to find the SSD and it is found that the last method is the best one to see the SSD by SEM.

Abstract: Chemical mechanical polishing (CMP) is the best global planarization technology of GLSI process. After CMP process, there may appear large roughness, micro scratch, dishing pit, erosion pit, with-in-wafer-non-uniformity (WIWNU), organic contamination, particles and metal ions pollution on wafer with copper interconnects. Surface measurement of CMP process on the wafer mainly involves the test of roughness, defects and the contaminations. Atomic force profiler (AFP) combined with the resolution of the AFM and long-range-scan ability of the steps instrument (100 mm), is suitable for CMP process which needs to measure both the planarization of long-range scanning and tungsten plug and copper interconnects with high resolution imaging. Optical detection technology combined with the advantages of dark and bright view detection is suitable for detection of particles, crystal originated pits (COP), defects, etc. The time-of-flight static secondary ion mass spectrometry (TOF-SIMS) and total reflection X-ray fluorescence (TXRF) are applicable to detect metal ions. The selection and use of advanced data analysis theory and method can help to improve the speed of analysis and to find the main factors of influence surface quality. Pareto diagram analysis is very beneficial for study polishing effects and the main reason of the surface state for Cu-CMP wafer. Nine sampling method and five sampling method fit to analysis the uniform surface distribution, on the contrast isometric sampling can reflect the distribution of the surface state along the radius difference.

Abstract: Ruthenium (Ru) and ruthernium alloys may be utilized as new copper barrier materials in copper interconnects of ultra-large scale integration (ULSI), and chemical mechanical polish (CMP) can be applied in planarization for ULSI production. In this paper, CMP experiments were done on high purity Ru by using home-made slurry, the effect of oxidizer, complexing agent, polishing downforce, pH value, inhibitor species and inhibitor concentration on the material removal rate (MRR) was investigated. The results revealed that MRR can reach 8.7 nm/min under the following conditions: the main constituents in slurry were 1 wt.% SiO2, 1 wt.% (NH4)2S2O8, 1 wt.% tartaric acid and 3 mM imidazole, the pH value was 8.0, the down force was 2.5 psi (17.24 kPa); the roughness Ra was 7.6 nm under these conditions.

Abstract: Osmium (Os) may be used as new barrier material in copper interconnects of ultra-large scale integration. In this work, chemical mechanical polish experiments were done on Os disk using home-made slurry, the effect of pH value, down force, chelating agents, inhibitor species, the concentration of the inhibitor, H2O2 concentration and SiO2 concentration on material removal rate (MRR) was investigated. The results reveal that MRR is 13.1 nm/min when the slurry contains 1wt.% H2O2, 1wt.% SiO2, 1 wt.% citric acid, 1mM BTA and pH =9 and the down force was 1 psi. The influence of the BTA concentration on the corrosion on the surface of Os was analyzed using electrochemical analysis method; it was found that the maximum value of Ecorr appeared when the BTA concentration was 1.5 mm

Abstract: Considering the technical status and existing problems of traditional silicon wafer chemical mechanical polishing (CMP), especially for the diameter of silicon wafer increasing, constantly, the surface quality and efficiency of silicon wafer polishing are becoming an urgent problem to be solved, so the research subject of ultrasonic vibration hybrid polishing new technique was proposed. By means of mechanism theoretical analysis research, firstly, the processing mechanism of hybrid polishing was studied systematically. An investigation of polishing mechanisms based on the micro-contact model between the polishing pad and the polishing surface of silicon wafer was developed. Polishing mechanism theoretical analysis shows that when ultrasonic vibrations combined with mechanical and chemical, the performance of polishing slurry is improved in the process of CMP, therefore to create favorable conditions. To verify the established theory, then, a series of experiments to investigate the traditional CMP are conducted, as well as the polishing tool with the forms of ultrasonic vibration, the polishing pad, the polishing surface quality, velocity at polishing point v, and slurry supplying Q on silicon wafer polishing. Experiment findings showed that, in the same polishing conditions, especially, hybrid polishing by ultrasonic-elliptic-vibration has gained more advantage over the effect of silicon wafer polishing. When ultrasonic-elliptic-vibration is put in polishing tool, the silicon wafer polished surface roughness Ra from the traditional method of polishing 0.077μm going down to the 0.042μm, the no-smooth rate KR which describes the polished surface morphology is significantly improved, and the material removal rate increases by 18%. Experimental research findings of the surface quality and the material removal mechanism are shown to be consistent with the theoretical analysis.

Abstract: A kind of slurry which is applicable for fine atomizing CMP was made and the optimal results were obtained through orthogonal experiments by comparing fine atomizing CMP and traditional CMP. The research results show that the material removal rate of fine atomizing CMP is 52.23% of traditional CMP, and the dosage of the slurry used in fine atomizing CMP only accounts for 10 vol% compared to traditional CMP. The surface roughness after the fine atomizing CMP is 2.5nm which is better than that of the traditional CMP (3.0nm).