Study On Characteristics Of Excimer Laser Lift-Off Polyimide Film

As a highly competitive polymer material in the world,polyimide film has good mechanical properties,mechanical properties and good chemical properties.It is widely used in aerospace,electrical and electronic,precision machinery,flexible display,transportation,laser and other fields.In recent years,with the rise of the flat panel display industry,PI films have played an important role in the manufacturing process of flexible displays.The lift-off effect of the glass substrate and the flexible substrate is critical to the quality assurance of the flexible display.Common methods are physical methods,chemical methods,and laser lift-off.Laser lift-off is a method of rapidly separating a glass substrate from a flexible substrate by laser energy.Compared with the other two kinds of stripping methods,it has the advantages of short action time,small heat-affected area,and rapid peeling,so it can be used in industrial production.Excimer laser has the characteristics of short wavelength,high single photon energy,and can realize flat-top laser beam.It is suitable as laser source for laser lift-off in industrial production.This topic uses 308nm excimer laser as the laser source and the excimer laser lift-off system was built to explore the factors affecting the excimer laser lift-off polyimide film,and the parameters suitable for the industrial production of excimer laser lift-off PI film were obtained The main contents include:1.The excimer laser lift-off system was built and debugged to provide a linear beam with a size of 100.0 mm x 0.3 mm with a maximum energy density of up to 400 mJ/cm2 and a pulse width of 30 ns.2.The thermodynamic process in excimer laser lift-off was analyzed to obtain the temperature field distribution of the film surface under the action of laser at any time.The factors affecting the temperature field distribution are laser energy density,laser pulse width,Initial temperature of the environment,and laser pulse frequency,and the energy density threshold of the 308 nm excimer laser lift-off PI film was obtained.3.Simulation software was used to simulate the surface temperature during film stripping.The temperature field distribution of the sample surface under the Gaussian beam and the uniform beam was simulated respectively.4.The experiment explored the effects of laser energy density,spot overlap ratio,pulse frequency and substrate temperature on laser lift-off effect.The morphology and film thickness of the peeled sample were observed by scanning electron microscopy.The results showed that The laser peeling energy threshold is 160 mJ/cm2.When the laser energy density reaches 190mJ/cm2,the spot overlap ratio is 68.17%,and the pulse frequency is 2Hz,the peeling effect is better.Increasing the substrate temperature facilitates the laser lift-off process.In this paper,the excimer laser lift-off process is theoretically analyzed and simulated,and the factors affecting laser lift-off are obtained.Through experimental research,the suitable parameters of the excimer laser lift-off PI film are obtained,which is of great significance for the application of polyimide film in the field of flexible electronics.