ILFA PCB's:
General design rules
 LEGENDSTANDARDHIGH END (ON REQUEST)
Max. PCB dimensions
420x570mmOn request
Thickness of flexible area over all
A≥0.065 mm (single sided) , ≥0.10 mm (double sinded)
On request
Thickness of reinforced connector area
B≥0.10 mm - 0.50 mm , Tolerance +/- 30 µm
≥ 0.50 mm , Tolerance +/- 10%
Metallized holes & milled cut-outs (details refer to the diameter of the drilling tool)
Drilling tool diameter

Specified end diameter + 100 µmOn request
Through hole
1Aspect Ratio 1:8, minimum Ø 75 µm
Aspect Ratio 1:10, minimum Ø 50 µm
Blind Via (from top or bottom)
2Aspect Ratio 1:1, minimum Ø 75 µm Aspect Ratio 1:1,2, minimum Ø 50 µm
Conductive pattern / remnant annular rings
Trace width min. (µm)
Depending on copper thickness

C≥75
≥50
Conductor spacing min. (µm)

Depending on copper thickness
D≥75
≥50
Annular ring to drilling tool-Ø (µm)

E≥100
≥75
Distance from hole to hole (µm)¹

Based on drilling tool-Ø
F≥100
Distance of conductive pattern to milling contour (µm)
G≥300
≥100
Distance of metallized hole to milling contour (µm)
Based on drilling tool-Ø
H≥350
≥200
Overlap of coverlay with solder mask (µm)
Only in a combined type

I300
On request

Solder mask / coverlay

Solder mask fillet width (µm)

With solder mask thickness lower 50 µm

J≥100
On request
Solder mask clearance to copper (µm)
K≥50
≥25
Coverlay clearance to copper (µm)
L≥150
≥100
Material thicknesses (µm)

Thickness of flexible polyimide (adhesiveless)
Preferably with rolled copper
Thickness: 25 - 150, Copper: 12 - 35

Copper: 9 ED-Copper, or Copper ≥70
Thickness of coverlay

DuPont FR or LF (preferably FR)
25, 38, 50, 75, 100, 150
Thickness of acrylic adhesive for reinforcement (thermosetting)

DuPont FR or LF (preferably FR)
25, 50, 75
Thickness of acrylic adhesive for reinforcement (transfer adhesive)

3M transfer adhesive
50 o. 130
Thickness of reinforcement
FR4 or Coverlay
Coverlay 25 - 150, FR4 50 - 3200
Bending
Minimum bending radius² single bend (mm)

Coverlay
Thickness of flexible area X 1
On request
Minimum bending radius² 4-12 cycles (mm)
Coverlay
Thickness of flexible area X 6

On request

Minimum bending radius² dyn. stress (mm)
Coverlay
Thickness of flexible area X ≥ 10
On request
Minimum bending radius² 4-12 cycles (mm)
Flexible solder mask

≥ 1,50 mm
On request
Other options are possible. Your layer structure is not standard? We will be happy to help you.
¹Distance from hole to hole: the measure refers to the distance between holes with equal electric potential. The minimum for holes with different potentials results from the minimum annular ring and the minimum conductor spacing.

²Bending radius: thickness of flexible area = addition of all materials (coverlay, adhesive, copper, base material). The information is only valid for a flexible core with maximum two copper layers.

VERSION: ILFA DFL 1

Download ILFA Design rules for single- and double-sided flexible PCB's.