Fineline width and line spacing

Chemical etching of a PCB is usually done with ammonium persulfate or ferric chloride. The thickness of standard copper sheets are typically 18 µm or 35 µm. Higher accuracy and fineline etching can be achieved by reducing the copper sheets thickness to 12, 9 or even 6 µm. Keep in mind that in most cases the minimum ratio for manufacturability between copper thickness and linewidth is approximately 1:2. This is because the chemical process leaves the copper closest to the base material wider than the copper farther away. From multiple suppliers, Azitech can etch finelines down to 50 µm.

For volume production in Asia, the fineline limit is currently 60 µm. Our special PCB production partners in Europe can do finelines down to 35 µm. Please contact Azitech’s PCB designers or Field Application Engineers for more information.

Fineline width and line spacingEUAsia
9 µm innerlayer50 µm50 µm
12 µm innerlayer50 µm66 µm
18 µm innerlayer50 µm80 µm
35 µm innerlayer50 µm90 µm
43 µm innerlayer100 µm100 µm
70 µm innerlayer150 µm150 µm
105 µm innerlayer200 µm180 µm
140 µm innerlayer250 µm225 µm
175 µm innerlayer250 µm250 µm
210 µm innerlayer250 µm300 µm
Conductor line width and space tolerance± 20%±- 20%