Papers by Keyword: Conduction Heating

Abstract: The conduction heating overcomes shortage of the radiation heating because of rapid heating and high energy efficiency. It is suitable for heating of blanks with an appropriate length/width ratio. In this study, a conduction heating system was developed in terms of Joule’s Law. Sensitivity of blank shapes on temperature distribution of hot stamping boron steel during conduction heating was investigated. Heating experiments of boron steel blanks with irregular-shapes, such as ladder, joist and rectangle with variable cross-section were implemented on the system. The results showed that the steady temperature was decided by the shape of the blanks. It was indicated that the steady temperature of the tested blanks was inversely proportion to the sectional area.

Abstract: Conduction heating overcomes the shortage of the furnace, due to rapid heating and high energy efficiency. The heating experiment of ultra-high strength boron steel (LG1500HS) of a rectangular blank was implemented on the conduction heating system. The variations of the average temperature rising rate, uniform temperature region and energy efficiency were investigated under the non-heating-retaining condition. The results show that the average temperature rising rate, uniform temperature region and energy efficiency are 44.5°C/s, 225 mm and 71.6%, respectively.

Abstract: Various types of conduction-based RTP systems are discussed. It is shown that simple hot plate systems suffer from severe bow of the wafer, when placed directly on the susceptor. This results in non-uniform heating. A solution is to place the wafer on pins; however, this considerably reduces the heat-up rate. An effective way to heat wafers through conduction fast and wellcontrolled is by placing it in a so-called gas bearing, an arrangement in which the wafer floats in between two hot blocks, at a well-controlled, small distance from both blocks. The heat-up rate in this so-called Levitor system is very high (~900°C/s) and uniform. It is demonstrated that this conduction-based system does not suffer from non-uniformities caused by variations in emissivity and/or pattern density across-wafer or within-die. In a direct comparison on pattern-dependent heating effects, substrates with trenches with varying dimensions are spike-annealed in a state-ofthe- art lamp system and in the Levitor. It was shown that temperature non-uniformities in the lampbased and the conduction-based systems are > 40°C and < 1°C, respectively. The conclusion is that the Levitor provides emissivity and pattern-independent heating.