Multilayer
Features manufacture multilayer and General tolerances
High level complexity and minimizing the space for the printed circuit boards have been the main reasons for the strong development of multiple layers printed circuit boards. The increase in the manufacturing of this kind of printed circuit boards has been constant in Lab Circuits during the last years. The classic structure of a multiple layers printed circuit board has some cores that have the ground and signal inner layers- and the conventional component and solder faces in the outside. The cores are made by a FR4 material sheet (glass fibre and epoxy resin with two external copper layers).
The core has its own body in the manufacture process until the multilayer pressing moment takes part, this means, it goes through a dry film process, exposure and a chemical process to end up creating one only structure that combines the cores with the prepreg sheets (glass fibre fabric impregnated with epoxy resin) and external covering copper sheets. This union is achieved by high temperature lamination pressing process.
Once it has been pressed, this structure has the same process as a double-sided printed circuit board.
PARAMETERS MANUFACTURE MULTILAYER
| CLASS 3 | CLASS 4 | CLASS 5 | CLASS 6 | CLASS 7 | ||
|---|---|---|---|---|---|---|
| Minimum plated through hole diameter | 
|
0,50 mm
|
0,30 mm | 0,30 mm
|
0,20 mm | 0,15 mm |
| Minimum non plated through hole diameter | 
|
0,60 mm | 0,40 mm | 0,40 mm | 0,30 mm | 0,25 mm |
| Aspect / Ratio | 
|
5 | 5 | 6 | 8 | 13 (maximun
thickness 2 mm) |
| Minimum outerlayer trace / spacing width (base copper thickness) | 
|
0,300 mm (17 µ m)
0,300 mm (35 µ m) 0,350 mm (70 µ m) 0,350 mm (105 µm) |
0,200 mm (17 µ m)
0,200 mm (35 µ m) 0,250 mm (70 µ m) 0,300 mm (105 µm) |
0,150 mm (17 µ m)
0,150 mm (35 µ m) 0,200 mm (70 µ m) 0,250 mm (105 µm) |
0,125 mm (17 µm)
0,150 mm (35 µm) 0,175 mm (70 µm) 0,200 mm (105 µm) |
0,100 mm (17 µ) |
| Minimum innerlayer trace / spacing width (base copper thickness) | 
|
0,250 mm (17 µ m)
0,300 mm (35 µ m) 0,300 mm (70 µ m) 0,350 mm (105 µm) |
0,150 mm (17 µ m)
0,200 mm (35 µ m) 0,200 mm (70 µ m) 0,300 mm (105 µm) |
0,125 mm (17 µ m)
0,150 mm (35 µ m) 0,175 mm (70 µ m) 0,250 mm (105 µm) |
0,100 mm (17 µ m)
0,125 mm (35 µ m) 0,150 mm (70 µ m) 0,200 mm (105 µm) |
0,075 mm (17 µ m)
0,100 mm (35 µ m) |
| Minimum Outer layer annular ring | 
|
0.22 mm | 0.17 mm | 0.13 mm | 0.10 mm | 0.075 mm |
| Minimum Signal inner layer annular ring | 
|
0.25 mm | 0.22 mm | 0.19 mm | 0.15 mm | 0.125 mm |
| Minimum annular spacing in ground plane | 
|
0.40 mm | 0.40 mm | 0.30 mm | 0.25 mm | 0.20 mm |
| Minimum microvia diameter | 
|
0,10 mm
(max. thickness 0.1 mm) |
0,075 mm
(max. thickness 0.065 mm) |
0,075 mm
(max. thickness 0.065 mm) |
||
| Microvia surface pad | 
|
0.35 mm | 0.30 mm | 0.25 mm | ||
| Microvia landing pad | 
|
0.30 mm | 0.25 mm | 0.25 mm | ||
| Minimum wall between
microvia and thru hole / blind/ buried |
|
0.22 mm | 0.15 mm | 0.10 mm | ||
| Minimum wall between microvias | 
|
0.23 mm | 0.15 mm | 0.10 mm | ||
| Minimum wall between microvias in two levels | 
|
0.23 mm | 0.15 mm | 0.10 mm | ||
| Copper filling microvias | 
|
- | - | - | - | - |
| Resin filling vias/microvias |  |
- | - | - | - |
Last update: 28-04-2023
Units: Milimeters
| CLASS 3 | CLASS 4 | CLASS 5 | CLASS 6 | CLASS 7 | ||
|---|---|---|---|---|---|---|
| Minimum plated through hole diameter |
|
20 mil | 12 mil | 12 mil | 8 mil | 6 mil |
| Minimum non plated through hole diameter |
|
24 mil | 16 mil | 16 mil | 12 mil | 10 mil |
| Aspect / Ratio |
|
5 | 5 | 6 | 8 | 13 (maximun
thickness 80 mils) |
| Minimum outerlayer trace / spacing width (base copper thickness) |
|
12 mil (½ oz)
12 mil (1 oz) 14 mil (2 oz) 14 mil (3 oz) |
8 mi l (½ oz)
8 mil (1 oz) 10 mil (2 oz) 12 mil (3 oz) |
6 mil (½ oz)
6 mil (1 oz) 8 mil (2 oz) 10 mil (3 oz) |
5 mil (½ oz)
6 mil (1 oz) 7 mil (2 oz) 8 mil (3 oz) |
4 mil (½ oz) |
| Minimum innerlayer trace / spacing width (base copper thickness) |
|
10 mil (½ oz)
12 mil (1 oz) 12 mil (2 oz) 14 mil (3 oz) |
6 mil (½ oz)
8 mil (1 oz) 8 mil (2 oz) 12 mil (3 oz) |
5 mil (½ oz)
6 mil (1 oz) 7 mil (2 oz) 10 mil (3 oz) |
4 mil (½ oz)
5 mil (1 oz) 6 mil (2 oz) 8 mil (3 oz) |
3 mil (½ oz)
4 mil (1 oz) |
| Minimum Outer layer annular ring |
|
9 mil | 7 mil | 5 mil | 4 mil | 3 mil |
| Minimum Signal inner layer annular ring |
|
10 mil | 9 mil | 8 mil | 6 mil | 5 mil |
| Minimum annular spacing in ground plane |
|
16 mil | 16 mil | 12 mil | 10 mil | 8 mil |
| Minimum microvia diameter |
|
4 mil
(max. thickness 4 mils) |
3 mil
(max. thickness 3 mils) |
3 mil
(max. thickness 3 mils) |
||
| Microvia surface pad |
|
14 mil | 12 mil | 10 mil | ||
| Microvia landing pad |
|
12 mil | 10 mil | 10 mil | ||
| Minimum wall between
microvia and through hole / blind/ buried |
|
9 mil | 6 mil | 4 mil | ||
| Minimum wall between microvias |
|
9 mil | 6 mil | 4 mil | ||
| Minimum wall between microvias into consecutive levels |
|
9 mil | 6 mil | 4 mil |
Last update: 28-04-2023
Units: Mils
MULTILAYER GENERAL TOLERANCES
| STANDARD | SPECIAL | ||
|---|---|---|---|
| Outer layer trace / spacing width |
|
±25% (35-70 µm)
±20% (17 µm ) |
±15% (35-70 µm)
±10% (17 µm) |
| Inner layer trace / spacing width | 
|
±25% (70 µm )
±20% (17-35 µm ) |
±15% (35-70 µm)
±10% (17 µm) |
| Plated hole diameter |
|
+0,10 mm / -0,05 mm
(or equivalent) |
+0,10 mm / -0,0 mm
(or equivalent) |
| Non plated hole diameter |
|
+0,10 mm / -0,0 mm
(or equivalent) |
±0,035 mm
(or equivalent) |
| Castellated plated holes | 
|
Total thickness circuit.....................>= 0,5 mm
Cross annular ring.......... detall - A >= 0,5 mm Minimum diameter..........detall - B >= 0,5 mm Longitudinal annular...... detall - C >= 0,15 mm Annular separation.........detall - D >= 0,15 mm Edge separation..............detall - E >= 2 mm |
- |
| Backdrill | 
|
Min. hole backdrill 0.5mm
More parameters see image |
-- |
| Scoring to copper clearance | 
|
Min. 1,0 mm. | Min. 0,75 mm. |
| Scoring positioning | 
|
±0,10 mm | ±0,075 mm |
| Scoring remaining thickness | 
|
±0,15 mm
|
±0,075 mm
|
| Board size | 
|
± 0,15 mm.
|
± 0,10 mm. |
| Total thickness tolerance | 
|
±10 % | ±5 % |
| Dielectric thickness | 
|
±10 % | ±5 % |
| Finished plated hole copper thickness | 
|
Average: 25 µm
Minim: 20 µm |
Average: 35 µm
Mínim: 30 µm |
| Blind/buried plated hole copper thickness | 
|
Average: 15 µm
Minimum: 13 µm |
Average: 25 µm
Minimum: 20 µm |
| Microvia Plated hole copper thickness | 
|
Average: 12 µm
Minimum:10 µm |
Average: 12 µm
Minimum:10 µm |
| Mínimum wall between same net plated through holes | 
|
0.30 mm | 0.25 mm |
| Minimum wall between different net plated through holes | 
|
0,40 mm. | 0,35 mm. |
| Minimum wall between non plated thruough holes | 
|
0,25 mm. | 0,20 mm. |
| Minimum annular ring non plated hole | 
|
0,25 mm
|
0,20 mm
|
| Track to non plated through hole minimum spacing | 
|
0,20 mm
|
0,15 mm
|
| Track to board edge minimum spacing | 
|
0,20 mm
|
0,15 mm
|
| Offset between board edge and drill | 
|
Max. 0,15 mm.
|
Max. 0,10 mm.
|
| Offset between drill to outlayer pad | 
|
Max. 0,10 mm.
|
Max. 0,075 mm.
|
| Offset between drill to innerlayer pad |
|
Max. 0,15 mm. | Max. 0,12 mm.
|
| Offset between layers | 
|
Max. 0,10 mm.
|
Max. 0,075 mm.
|
| Soldermask feature tolerance | 
|
Max. 0,15 mm. | Max. 0,075 mm. |
| Soldermask min Dam size on fiber | 
|
SOLDERMASK GREEN COLOR
Dam 70µm if final copper thickness is 17÷54µm. Dam 85µm if final copper thickness is 55÷85µm. Dam 105µm if final copper thickness is 86÷155µm. SOLDERMASK WHITE COLOR Dam 110µm if final copper thickness is 17÷54µm. Dam 110µm if final copper thickness is 55÷85µm. Other final copper thickness > 85µm, to consult. OTHER SOLDERMASK COLORS Dam 80µm if final copper thickness is 17÷54µm. Dam 95µm if final copper thickness is 55÷85µm. Dam 105µm if final copper thickness is 86÷155µm. |
-- |
| Soldermask min Dam size on copper | 
|
SOLDERMASK GREEN COLOR
Dam 60µm if final copper thickness is 17÷54µm. Dam 70µm if final copper thickness is 55÷85µm. Dam 85µm if final copper thickness is 86÷155µm. SOLDERMASK WHITE COLOR Dam 110µm if final copper thickness is 17÷54µm. Dam 110µm if final copper thickness is 55÷85µm. Other final copper thickness > 85µm, to consult. OTHER SOLDERMASK COLORS Dam 70µm if final copper thickness is 17÷54µm. Dam 80µm if final copper thickness is 55÷85µm. Dam 90µm if final copper thickness is 86÷155µm. |
- |
| Photoimageable soldermask clearance | 
|
0.06 mm | -- |
| Silkscreened soldermask clearance |
|
0,20 mm
|
0,15 mm
|
| Legend minimum line | 
|
0,125 mm
|
0,10 mm
|
| Conductive ink (graphite) overlapping | 
|
0,20 mm
|
0,125 mm
|
| Conductive ink (graphite) spacing | 
|
0,50 mm | 0,40 mm |
| Conductive ink to pad spacing | 
|
0,40 mm | 0,30 mm |
| Peel-off mask overlapping | 
|
0.8 mm
|
0,50 mm
|
| Peel-off mask to pad spacing | 
|
1 mm | 0,70 mm |
| Peel-off mask to board
edge spacing |
|
1 mm | 0,70 mm |
| Maximum peel-off mask filled hole | 
|
1.80 mm | 2 mm |
| Bow and twist | |
Maxim 1% | Maxim 0,5 % |
| Insulation resistance | |
Minim 0,5 MOhm | Minim 2,0 MOhm |
| Continuity | |
Maxim 10 Ohms | - |
| Ionic contamination | |
Max. 0.4 µg Eq. NaCl/cm² | Max. 0.4 µg Eq. NaCl/cm² |
| Other features | |
See spec.
IPC-A-600 Rev K jul-20 |
- |
Last update: 13-06-2023
Units: Milimeters
| STANDARD | SPECIAL | ||
|---|---|---|---|
| Outer layer trace / spacing width |
|
±20% (½ oz )
±25% (1-2 oz ) |
±10% (½ oz )
±15% (1 - 2 oz) |
| Inner layer trace / spacing width |
|
±20% (½ - 1 oz)
±25% (2 oz) |
±10% (½ oz )
±15% (1 - 2 oz ) |
| Plated hole diameter |
|
+4 mil / -2 mil
(or equivalent) |
+4 mil / -0,0 mil
±2 mil |
| Non plated hole diameter |
|
+4 mil / -0,0 mil
(or equivalent) |
±1.4 mil
(or equivalent) |
| Castellated plated holes |
|
Total thickness circuit.....................>= 0,02 mil
Cross annular ring.......... detall - A >= 0,02 mil Minimum diameter..........detall - B >= 0,02 mil Longitudinal annular...... detall - C >= 0,006 mil Annular separation.........detall - D >= 0,006 mil Edge separation..............detall - E >= 0,08 mil |
- |
| Backdrill | |
Min. hole backdrill 0.5mm
More parameters see image |
- |
| Scoring to copper clearance |
|
Min. 40 mil. | Min. 30 mil |
| Scoring positioning |
|
± 4 mil | ± 3 mil |
| Scoring remaining thickness |
|
± 4 mil
|
± 2 mil
|
| Board size |
|
± 6 mil.
|
± 4 mil. |
| Total thickness tolerance |
|
±10 % | ±5 % |
| Dielectric thickness |
|
±10 % | ±5 % |
| Finished plated hole copper thickness |
|
Average: 0.7 oz
Minimum: 0.6 oz |
Average: 1 oz
Minimum: 0.86 oz |
| Blind/buried plated hole copper thickness |
|
Average: 0.4 oz.
Minimum: 0.37 oz. |
Average : 0.7 oz.
Minimum: 0.6 oz. |
| Microvia Plated hole copper thickness |
|
Average: 0.4 oz.
Minimum:0.37 oz. |
Average: 0.7 oz.
Minimum: 0.6 oz. |
| Mínimum wall between same net plated through holes |
|
12 mil. | 10 mil. |
| Minimum wall between different net plated through holes |
|
16 mil. | 14 mil. |
| Minimum wall between non plated thruough holes |
|
10 mil. | 8 mil. |
| Minimum annular ring non plated hole |
|
10 mil.
|
8 mil. |
| Track to non plated through hole minimum spacing |
|
8 mil. | 6 mil. |
| Track to board edge minimum spacing |
|
8 mil. | 6 mil. |
| Offset between board edge and drill |
|
Max. 6 mil.
|
Max. 4 mil.
|
| Offset between drill to outlayer pad |
|
Max. 4 mil.
|
Max. 3 mil.
|
| Offset between drill to innerlayer pad |
|
Max. 6 mil. | Max. 5 mil.
|
| Offset between layers |
|
Max. 4 mil.
|
Max. 3 mil.
|
| Soldermask feature tolerance |
|
Max. 6 mil. | Max. 3 mil. |
| Soldermask min Damm size on fiber |
|
SOLDERMASK GREEN COLOR
Damm 2,75mil if final copper thickness is 0.66÷2.12mil. Damm 3,35mil if final copper thickness is 2.16÷3.35mil. Damm 4,13mil if final copper thickness is 3.38÷6.10mil. SOLDERMASK COLOR BLANCO Damm 4,33mil if final copper thickness is 0.66÷2.12mil. Damm 4,33mil if final copper thickness is 2.16÷3.35mil. Other final copper thickness > 3.35mil, to consult. OTROS COLORES SOLDERMASK Damm 3,15mil if final copper thickness is 0.66÷2.12mil. Damm 3,75mil if final copper thickness is 2.16÷3.35mil. Damm 4,13mil if final copper thickness is 3.38÷6.10mil. |
-- |
| Photoimageable soldermask clearance |
|
2.5 mil. | -- |
| Silkscreened soldermask clearance |
|
8 mil. | 6 mil. |
| Legend minimum line |
|
5 mil. | 4 mil. |
| Conductive ink (graphite) overlapping |
|
8 mil.
|
5 mil. |
| Conductive ink (graphite) spacing |
|
20 mil. | 16 mil. |
| Conductive ink to pad spacing |
|
16 mil. | 12 mil. |
| Peel-off mask overlapping |
|
32 mil. | 20 mil. |
| Peel-off mask to pad spacing |
|
40 mil. | 28 mil. |
| Peel-off mask to board
edge spacing |
|
40 mil. | 28 mil. |
| Maximum peel-off mask filled hole |
|
71 mil. | 79 mil. |
| Bow and twist | |
Maxim 1% | Maxim 0,5 % |
| Insulation resistance | |
Minimum 0,5 MOhm | Minimum 2,0 MOhm |
| Continuity | |
Maxim 10 Ohms | - |
| Ionic contamination | |
Max. 0.4 µg Eq. NaCl/cm² | Max. 0.4 µg Eq. NaCl/cm² |
| Other features | |
See spec.
IPC-A-600 Rev K jul-20 |
- |
Last update: 12-06-2023
Units: Mils
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