Abstract: A plastic capillary electrophoresis chip is a novel kind of miniaturized device for biochemistry analysis. The major advantages of the chip include high transmittance for light; low conductivity for electrokinetic pumping and electro- phoretic separation; low cost for high volume production and disposal and easily manufacturing for high aspect ratio of microchannels on the chip. A process of thermal bonding for plastic capillary electrophoresis chips is studied, the relationships between the changes of the dimensions of the microchannels and the process conditions of thermal bonding and hot embo- ssing, including temperature, pressure and time are established by experiment, based on these the ways to reduce the changes are proposed, which lays the foundation for basic theories and techniques of structural design and manufactures of the plastic chip.

Key words: Biochips, Capillary electrophoresis chips, MEMS, Microfabrication, Microfluidic chips, m-TAS, Thermal bonding