Development of Fluid-Based Heating and Pressing Systems for Micro Hot Embossing
Date Issued
2004
Date
2004
Author(s)
Chang, Jer-Haur
DOI
zh-TW
Abstract
This thesis is devoted to the development new system and process for large-area hot embossing. First, a series of hot embossing experiments were conducted to transcript the micro U-groove features in a stamper onto large thin thermoplastic films with traditional hot press. Film embossing is found different from plate embossing in applying slight pressure during heating and backing the stamps with cushion pads. The formability of amorphous PC films was found to be much larger than that of the semi-crystalline PET films.
During conventional hot embossing, the substrate and the stamp are brought into contact and are compressed directly by the hot plates of the machine. The accuracy and area of replication are limited due to the inherent non-uniform pressure distribution. Si-wafers are too brittle to be used as embossing tools with the conventional hot embossing operation.
In this study, three innovative methods of rapid heating and uniform pressing for micro hot embossing were developed. Fluids were used as heating and pressing media. With these three systems, the temperature of substrate rises rapidly and uniform pressure is exerted over the whole substrate. The working fluids used in this experiment included steam, gas, and oil. In addition, rapid heating through far infrared radiation (FIR) was also implemented with a gas pressurized hot embossing process. It was found that a 0.2 millimeter-thick PVC substrate can be heated from 25oC to 130oC in 30 seconds using steam heating, in only 25 seconds using FIR heating, and in 3.5 minutes using oil heating. The heating speeds of all three methods are much faster than those using conventional hot-plate heating, which takes more than 10 minutes. Successful replications of micro-features onto 4-inch and 12-inch substrates have been achieved.
The simulations of heat transfer in these new processes are also carried out with finite element software of ANSYS. Heat transfer analysis proves helpful in predicting temperature response and in the design of process.
Subjects
流體
快速加熱冷卻
氣體
大面積
晶圓
微熱壓
熱壓
微結構
hot embossing
rapid heating
fluid
gas
wafer
Type
thesis
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