In the field of the semiconductor manufacturing, the density and miniaturization of integrated circuits are progressing, and the process/design rule extends to several nanometers. It also means that Moore's law will come to an end in near future. Under such circumstances, stacking of the semiconductor integrated circuit in the thickness direction, stacking of metal wiring for speeding up, and thinning of the integrated circuit chip have become important. In this report, an outline of the silicon semiconductor manufacturing process, which is becoming more and more highly integrated is introduced, and at the same time, some explanations related to the tribology are also added.
The surface of a semiconductor substrate is flattened with high accuracy by a planarization polishing technique. To obtain the high flatness for a large sized wafer, various polishing simulations have been developed. The first part of this report describes the polishing simulation theory and some applications for a single side polishing. The simulation used for the oscillation polishing with a small tool calculates the change of the wafer profile and optimizes the oscillation speed distribution to obtain the flatness of 0.1μm. The latter part of this report introduces a simulation for a double side polishing, the idea of calculating the pressure distribution and a simulation example.
With the spread of IoT, various semiconductor electronic components are produced, and the semiconductor manufacturing process becomes more complicated. Magnetic fluid seals are important as sealing devices used in semiconductor manufacturing equipment to cope with such processes. In particular, the use of a fluorine-based oil-magnetic fluid having excellent heat resistance makes it possible to manufacture semiconductors in more diverse and severe processes, and it is expected that the maintenance cost can be reduced and the throughput can be increased by prolonging the life of the seal. In the future, if the operating temperature range of magnetic fluid becomes wider, it is expected that the applications will increase in the field of electric vehicle, aerospace, energy, etc.
In the semiconductor manufacturing processing, the ultra-precision positioning technique is essential. We have been developing ultra-precision positioning stage systems and drive actuators mounted on those devices, and supplying them into the semiconductor market for more than 20 years. In this paper, we, firstly, describe our basic study of the driving method and control techniques to actualize the high-precision positioning. Secondly, we introduce a technique for designing linear motor and pneumatic servo actuator which has been recognizing to achieve ultra-precision positioning accuracy. Furthermore, we discuss current and future issues of XY stage system applied for semiconductor wafer. Finally, we introduce an example of the development of the pneumatic servo stage technology applied for electron beam exposure system.
The effect of temperature on the lubricity of molybdenum dithiocarbamate(MoDTC) and co-additives was investigated by a ball on disk tribometer at temperatures of 25°C, 40°C, 60°C and 80°C. MoDTC was added in polyalphaolefin(PAO) as base oil. Calcium sulfonate(CaSu), calcium borate dispersed in calcium sulfonate(CaBSu), calcium salicylate(CaSa) and calcium phenate (CaPh) were used as a co-additive. In the test with MoDTC alone, the friction coefficient decreased only at 80°C, and the friction coefficient was not stable and fluctuated during the test at 80°C. The friction coefficient became stable with co-additives. The co-additives were classified in two groups on the basis of friction behavior. When CaSu or CaBSu was used as a co-additive, the friction coefficient decreased even at 60°C and 80°C. On the other hand, the friction coefficient decreased only at 80°C with CaSa or CaPh. The results of XPS analysis and HR-TEM observation revealed that MoS2 was formed clearly when the sulfonates were added to the lubricant oil with MoDTC. The behavior of friction coefficient was closely dependent on the kind of co-additives and the oil temperature. As a role of the sulfonate for the MoS2 layer formation, it is thought that sulfonates act as a S source for MoS2 and a binder for the boundary layer.
Lubrication mechanism of the vane-top of multiple vane type compressors was investigated to extract dominant parameters deteriorating oil film formation under high suction pressure conditions leading to abnormal wear of the cylinder inner surface. A calculation model was constructed using coupled analysis of the vane-top part and the vane-slot part, in which the mixed lubrication theory was applied. Of the parameters used for calculation of the oil film thickness, the viscosity of the mixture in which the refrigerant is dissolved in oil and the boundary friction coefficient at the vane-slot part were experimentally obtained, and the force from the back-part of the vane and the action force from the gas pressure inside the compression chamber were obtained based on the theory. The proposed calculation analysis was verified by comparing the calculated results of oil film thickness with the separation degree measured by electrical insulating method on the experiments. Besides, the parametric study of calculation analysis revealed that the causes of poor oil film formation at the vane-top under high suction pressure conditions were the high boundary friction coefficient under the starved conditions and the low refrigerant solution viscosity at the vane-top part.