Polishing slurry

Vertical Pressure Leaf Filters are essentially the same as Horizontal Plate Filters except for the orientation of the filter elements which are vertical rather than horizontal. They are applied for the polishing slurries with very lov solids content of 1-5% or for cake filtration with a solids concentration of 20-25%. As with the horizontal plate filter the vertical leaf filters are also well suited for handling flammable, toxic and corrosive materials since they are autoclaved and designed for hazardous environments when high pressure and safe operation are required. Likewise, they may be readily jacketed for applications whenever hot or cold temperatures are to be preserved.The largest leaf filters in horizontal vessels have a filtration area of 300 m and vertical vessels 100 m both designed for an operating pressure of 6 bar. 

CMP of different materials needs polishing slurries with different pH value, e.g., slurry for oxide CMP has a basic pH... 

CMP slurries are shipped to user sites in ready-to-use strength or as a concentrate, which must be diluted to use strength or mixed with one or more chemicals to create the final CMP polishing slurry. Examples of widely used oxide and tungsten polishing slurries, which require various blending ratios, are listed in Table IV. 

In general, the rule of thumb is to add the diluting component to the abrasive component. There are, however, exceptions to this rule of thumb, so experience and the recommendations of the slurry manufacturer should be considered. In the case of silica-abrasive oxide-polishing slurries, this means slurry first, water second. Even when practiced in this manner, slurry diluted at the user site will typically have more agglomerates than slurry diluted to use-concentration by the slurry manufacturer. The primary reason... 

Oxide-polishing slurry Potassium hydroxide 1-3 (% by weight)... 

Coppeta et al. [10] made slurry film measurements during using laser-induced fluorescence. By addition of a fluorescent dye to the polishing slurry film thickness was experimentally from the fluorescence intensity of the lubrication film as measured through a transparent substrate. Film thickness measurements were in good agreement with those of Levert et al. [7,8]. This technique can also be used to study slurry transport across the wafer surface, diameter variation in lubrication film thickness, and slurry mixing effects [11]. 

In our view, the polishing slurry would have an indefinite life were it not for the fact that the glass products gradually dilute and contaminate the slurry. The build-up of alkali ions is so great, that daily pH adjustments are necessary in large central system slurry tanks. 

Typically, both the wafer carrier and platen are rotated in the same direction. A downforce is applied while the wafer carrier and platen are rotated on their own axes coc and co, respectively. The polishing slurry is dispensed from a tube located at the center of the pad, and as the platen rotates the slurry is transported between the wafer and the pad [3-6]. In addition to the rotary platform, an orbital design has also been implemented (Fig. 3.3) [2]. The operating principle for the orbital design is similar to the rotary platform, except that the polishing head and table are in orbital motion to each other. In addition, the slurry is usually delivered through the pad. 

CMP is a wet process with DI water and/or polishing slurry present. During polishing, pad is under the attack of water, slurry chemicals, and abrasive particles at elevated temperature due to the friction force among wafer-particle-pad contact. This leads to changes in pad s physical and mechanical properties that influence polishing performance. 

Basim GB, Adler JJ, Mahajan U, Singh RK, Moudgil BM. Effect of particle size of chemical mechanical polishing slurries for enhanced polishing with minimal defects. J Electrochem Soc 2000 147(9) 3523-3528. 

A slurry performance may be heavily influenced by the selection of other consumables. For example, it has been demonstrated that a concentric grooved pad enhanced the performance of a high-selectivity slurry (Rohm Haas—XSHD3562) [22]. The pad allows the nitride film to be truly a polishing stop layer. In this study, different combinations of rotary and linear polishing platforms in addition to conventional and high-selectivity polishing slurries were evaluated. It was determined that the best results were achieved... 

Singh RK, Roberts BR. On extensive pump handling of chemical-mechanical polishing slurries. Proceedings of the 12th Annual lEEE/SEMI ASMC 2001 Apr 23-24 Munich, Germany. 

Data, using the Malvern Ultrasizer has been presented from two applications, chemical mechanical polishing slurries used in the semiconductor industry and monitoring a crystallization growth system [244]. 

In the presence of a lubricating liquid (i.e., the polish slurry) two solid bodies in relative sliding motion will interact in one of... 

Copper polish slurry formations may contain dissolved NH, ig) to complex the copper ions and increase copper solubility. In 1 vol% NH4OH, for example, Cu ions are complexed by NHj according to ... 

The results of Farkas et al. demonstrate that electrochemical processes are important in metal CMP and that potentiodynamic measurements can predict metal dissolution and surface film formation in these slurries. This information can then be used to predict the polish rate and planarization performance of a polish slurry. These relatively simple electrochemical measurements may then be used to screen slurry candidates quickly and efficiently. 

It is hypothesized that a passivated layer may form on metal surfaces exposed to the polishing slurries. Using the... 

In this study, we have characterized the effects of abrasive properties, primarily particle size, on the Chemical Mechanical Polishing (CMP) of oxide films. Sol-gel silica particles with very narrow size distributions were used for preparing the polishing slurries. The results indicate that as particle size increases, there is a transition in the mechanism of material removal from a surface area based mechanism to an indentation-based mechanism. In addition, the surface morphology of the polished samples was characterized, with the results showing that particles larger than 0.5 im are detrimental to the quality of the Si02 surface. 

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