μ-BGA 절단을 위한 레이저 가공 파라미터 연구

초록

In this paper, I have studied minimization of the kerf-width and surface buring which are occured after the singulation process of multi layer μ-BGA( thickness 1.1 ㎜, 0.9 ㎜) with a pulsed Nd:YGA( = 532 ㎚, repetition rate = 10㎐) laser. The thermal energy of a pulsed Nd:YGA laser in used to cut the copper layer. I have studied are minimization of the surface buring and kerf-width using a photo resist, N2 blowing and polyester double sided tape as a cutting parameter. The N2 blowing reduces a laser energy loss by debris and suppresses a surface carbonization. Also, I have studied characters of cutting with a choice of side of laser beam incidence. The SEM(Scanning Electron Microscope), non-contract 3D inspector and high-resolution microscope are used to measure kerf width and surface state. The optimum value of 1.1 ㎜ μ-BGA singulation is 524 ㎛ that is reduced kerf width of 60 % with N2 blowing. And I obtained reduction of carbonization of 68 % with a polyester double side tape in 0.9 ㎜ μ-BGA. I used laser intensity of 1.91 * 106 / ㎝2 in this study