Ultra-smooth surface polishing

In this chapter, an introduction of experimental and theoretical studies on nanoparticles collision has been made, as nanoparticles impact on an ultra-smooth surface always occur in the ultra-smooth surface manufacturing. Then the development of CMP technology is introduced. And at last, the polishing of magnetic head surface is discussed. 

M. White, K. Moeggenborg, F. BatUo, J. Gilliland, N. Naguib, High rate silicon carbide polishing to ultra-smooth surfaces, in Presented at MRS Proceedings, 2007. 

For preparing smooth surface RDE, the GC (or Pt, or Au) disk is polished with the 1, 0.3, and 0.05 pm Y-AI2O3 in succession until the mirror surface is formed. Then this electrode surface is washed using pure acetone and DI water under the ultra-sonication for at least three times, and put into the electrochemical cell for measurements. 

The construction of silicon chips requires materials of high purity and consistent internal structure. This, in turn, requires precisely controlled methods in the production of both the materials and the structures for which they are used. Large crystals of ultra-pure silicon are grown from molten sihcon under strictly controlled environmental conditions. Thin wafers are sliced from the crystals and then polished to achieve the desired thickness and mirror-smooth surface necessary for their purpose. Each wafer is then subjected to a series of up to five hundred, and sometimes more, separate operations hy which extremely thin layers of different materials are added in precise patterns to form miUions of transistor structures. Modern CPU (central processing unit) chips have between 10 and 10 separate transistors per square centimeter etched on their surfeces in this way. 

Recently, we reported that sub nanometer-thick Ag films deposited on Si (111) surface showed good lubricity under ultrahigh vacuum (UHV) enviromnent [4, 5]. In these cases. Si wafer with a very smooth surface was selected as the substrate, and the counter surface was finely polished diamond, which is not reactive with Ag. As a result, adhesive force and displacement taking place in the Ag layer could be minimized, and the coefficient of fiiction decreased to the 0.01 range. The film thickness effect might be apparent in such an ultra-thin region ... 

An ideal substrate would be smooth, rigid (i.e. a polished metal), coated with an ultra-thin PDMS layer anchored by a well-understood and controllable chemistry. This has been achieved by taking semi-conductor silicon wafers which have a thin oxidized silica layer which can be treated by a self-assembling silane monolayer, such as vinyl terminated alkyltrichlorosilane. This can then be reacted with SiH-containing PDMS this hydrosilylation reaction is well-understood and the random substitution of such SiH groups along a PDMS chain has been well established by NMR studies. The low hysteresis surface that can be obtained in this manner is illustrated by the data in Table 4. 

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