Laser micro-welding of transparent materials by a localized heat accumulation effect using a femtosecond fiber laser at 1558 nm

We report on laser micro-welding of materials based on a localized heat accumulation effect using an amplified femtosecond Er-fiber laser with a wavelength of 1558 nm and a repetition rate of 500 kHz. We demonstrated the welding of non-alkali alumino silicate glass substrates, resulting in a joint strength of 9.87 MPa. We also welded a non-alkali glass substrate and a silicon substrate using the 1558-nm laser pulses, resulting in a joint strength of 3.74 MPa. Our laser micro-welding technique can be extended to welding of semiconductor materials and has potential for various applications, such as three-dimensional stacks and assembly of electronic devices and microelectromechanical system devices.