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AUGUST 2022 I PCB007 MAGAZINE 73 system (LIFT), as seen in Figure 3. ese new technologies extend the number of inks that can use inkjet printing. e capability of a head is a function of the droplet size, its overlap, and the frequency the head can achieve, now 80 kHz. is permits resolution of 5,000 dpi and resulting minimum copper line widths of 40 to 70 microns. To improve both speed and density, inkjet- ting has taken a page from the DMD micro- mirrors exposure book and now uses multiple inkjet heads to achieve this performance. Fig- ure 4 shows a test vehicle from the Center for Microsystems Technology (CMST) of Ghent University and IMEC with etched traces down to 40 microns. Figure 5 illustrates this etching/plating resist capability on a Samsung panel with the Sam- sung printhead using five pl-256 nozzles. Ink or Pastes ere were numerous challenges with ink formulation, including adhesion, curing, and especially spreading after jetting. Figure 4 illustrates the difference between general ink- jet printing on paper vs. inkjet printing on a PCB. Figure 4: Laser induced forward transfer (LIFT) system 4 and new piezo-acoustic head 5 . Figure 3: Another example of a production inner layer, before and after etching of 75/75-micron traces and spaces 3 .