Laser direct image

LDI laser direct image LOM laminated object manufacturing... 

The RCC approach suffers from misregistration of window opening to capture pad when the surface and capture pad diameter becomes less than 250 pm, which causes serious defects (see Fig. 22.22). Laser via process practitioners have several solutions to this problem.They can use liquid resin or resort to a Yag or Yag/CO2 laser. Since a Yag laser can break through copper foil, the beam can be directed to the capture pad position accurately. Another choice is to use laser direct imaging (LDI) for window etching in order to benefit from the speed of the CO2 laser. 

In the past, several photoresists were formulated for exposme at a visible wavelength,450 nm, using specialized exposure equipment—either visible lasers or magnified projection printing. More recently, laser direct imaging (LDI) based on the Ar+ laser ontpnt clnstered aronnd 360 nm has been commercialized. Conventional photoresists can be exposed on LDI eqnipment, bnt higher photospeed has been key to the productivity and economics of LDI. 

FIGURE 26.18 Schematics of laser direct imaging equipment (a) flatbed platen (b) external drum. 

McKeever, M. R., Laser Direct Imaging— Trends for the Next Generation of High Performance Resists for Electronic Packaging, Proceedings, S12-1,2000IPC Expo and Technical Conference, San... 

Taff, L, and Benron, H., Liquid Photoresist for Thermal Laser Direct Imaging, Board Authority supplement to CircuiTree, Vol. 1, No. 3, October 1999, p. 66. 

Exposure Collimated light source, auto aligner Laser direct imaging... 

Laser direct imaging equipment (LDI) is capable of making the dimensional corrections for the serious distortions of the unstable flexible materials promptly. It provides a high productivity for the prototype or middle volume productions. On the other hand, it is not very capable for traces finer than 25 microns lines and spaces. Lower throughput compared to traditional exposure machines, especially for double-side imaging, is the barrier for the volume productions. 

Innovative technologies have been developed for each unit process, such as the collimated hght source exposure machine and the laser direct imaging system. 

Exposure Collimated light source with glass mask (-15-pm line/space) Autoalignment system for double-sided drcuits (with accurate dimension compensation system, -5 pm) Roll-to-roll conveyor system with low tension Laser direct imaging system (30 10 pm line/space)... 

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