scholarly journals Direct Laser Drilling in Copper Clad Printed Wiring Boards (Effect of Surface Treatment on Drilled Blind Via-Hole Quality)

2008 ◽  
Vol 74 (747) ◽  
pp. 1411-1417 ◽  
Author(s):  
Toshiki HIROGAKI ◽  
Eiichi AOYAMA ◽  
Keiji OGAWA ◽  
Shogo MATSUTANI ◽  
Tsukasa AYUZAWA
Keyword(s):  
Surface Treatment ◽  
Laser Drilling ◽  
Printed Wiring Boards ◽  
Hole Quality ◽  
Direct Laser ◽  
Via Hole ◽  
Effect Of Surface

scholarly journals Evaluation of Blind Via Hole Quality on Multi-Layer Printed Wiring Boards by Cu Direct Laser Drilling

2006 ◽  
Vol 55 (3) ◽  
pp. 335-340 ◽  
Author(s):  
Toshiki HIROGAKI ◽  
Eiichi AOYAMA ◽  
Keiji OGAWA ◽  
Ryu MINAGI ◽  
Toshiki MURAKAMI ◽  
...  
Keyword(s):  
Laser Drilling ◽  
Printed Wiring Boards ◽  
Hole Quality ◽  
Direct Laser ◽  
Via Hole

Cu-Direct Laser Drilling of Blind Via-Hole in Multi-Layer PWBs: Influence of Surface Treatment on Drilled Hole Quality

2009 ◽  
Author(s):  
Toshiki Hirogaki ◽  
Eiichi Aoyama ◽  
Keiji Ogawa ◽  
Tsukasa Ayuzawa
Keyword(s):  
Surface Treatment ◽  
Co2 Laser ◽  
Copper Foil ◽  
Laser Energy ◽  
Copper Surface ◽  
Laser Drilling ◽  
Hole Quality ◽  
Direct Laser ◽  
Overhang Length ◽  
Direct Drilling

This report describes the quality assessment of Blind Via Holes (BVHs) of Printed Wiring Boards (PWBs) drilled by a CO2 laser using Cu-direct drilling. In the Cu-direct drilling method, the copper foil and the build-up layer are melted at the same time, and the surface is treated to increase the laser energy absorbed by the copper foil since an untreated copper surface reflects most of the 10.6-μm-wavelength CO2 laser beam. However, there are few reports dealing with Cu-direct laser drilling of PWBs. In addition, when copper and resin with different processing thresholds are drilled at the same time, occurrences of a defect called overhang have been observed. So, in this report, first we propose a new method using thermography to measure the absorptance of a PWB surface for a CO2 laser. Moreover, we investigate how surface treatment of the outer copper foil influences the quality of a laser-drilled hole. Then, we observe the circumference of a point irradiated with the CO2 laser and explain how melting processes are different from surface treatment. Finally, based on the research we establish a method in order to cut down the overhang length as a parameter of drilled-hole quality. We also show that a high absorptance improves BVH quality.

Cu-Direct Via-Hole Drilling of Aramid Fiber Reinforced Build-Up Layer by CO2 Laser Beam

2005 ◽  
Author(s):  
Eiichi Aoyama ◽  
Toshiki Hirogaki ◽  
Keiji Ogawa ◽  
Nobuyuki Doi ◽  
Ryu Minagi
Keyword(s):  
Co2 Laser ◽  
Copper Foil ◽  
Effective Means ◽  
Hole Diameter ◽  
Hole Drilling ◽  
Printed Wiring Boards ◽  
Laser Absorption ◽  
Direct Laser ◽  
Via Hole ◽  
The Difference

This report describes the features of Cu-direct laser drilled hole quality on multi-layer Printed Wiring Boards (PWBs). Cu-direct laser drilling drills the outer copper foil and build-up layer at the same time, which makes it difficult to form a blind via hole (BVH) with high quality because the copper foil has high reflection coefficient for a CO2 laser with wavelength 10.6 μm. Therefore, this study focused on improving drilled hole qualities such as diameter and overhang. First, the influence of laser irradiation conditions on forming BVH and the drilled hole diameter were investigated in detail. Second, a new method employing thermography was proposed in order to evaluate the absorption of copper foil after surface treatment. Third, the effect of mixing fillers into the build-up layer in order to reduce the amount of overhang was shown to be effective both experimentally and theoretically. As a result, it is clear that decreasing the difference in the laser absorption rate of the outer copper foil is an effective means to control the hole diameter and reducing the heat characteristic difference between the outer copper foil and the build-up layer can effectively decrease overhang.

Sign in / Sign up

Export Citation Format

Share Document