VdL

Citation

(1999), "VdL", Circuit World, Vol. 25 No. 3. https://doi.org/10.1108/cw.1999.21725cab.007

VdL

IPC

VdL

Keyword VdL

In May 1998 the CEOs of five European companies (AT&S, Fuba, Philips, Schweizer and STP), all members of the DRT (Directors Round Table), established by the chairman of the VdL, formed a working group with the aim of developing design rules for HDI boards (Table I and Figure 1).

Table IDesign rules for HDI cards (high density interconnection cards).All values are minimum values. High standard (not every company can fulfil all characteristics)

Symbol	Description	Standard	High standard
A	Linewidth outerlayer	0.125mm	0.100mm
A	Linewidth outerlayer Cu thickness < 25µm	0.125mm	0.100-0.075mm
B	Spacing outerlayer	0.125mm	0.100mm
B	Spacing outerlayer Cu thickness < 25µm	0.125mm	0.100-0.75mm
C	Linewidth innerlayer Cu < 20µm	0.100mm	0.075mm
D	Spacing innerlayer Cu < 20µm	0.100mm	0.075mm
E	Mircrovia holesize	0.125mm	0.100-0.075mm
F	Microvia landing pad	0.30mm	0.25mm
G	Microvia pad	0.30mm	0.25mm
H	Drill size buried hole	Max 0.30mm	0.20mm
I1	Pad size buried hole outerlayer	0.50mm	0.50-0.40mm
I2	Pad size buried hole innerlayer	0.70mm	0.55mm
J	Drill size plated through hole	0.30mm	0.20mm
K1	Pad six plated through hole outerlayer	0.55mm	0.5-0.40mm
K2	Pad size plated through hole innerlayer	0.70mm	0.55mm
L	L/E (aspect ratio) microvia	¾ 1	¾ 1
M	Min core thickness power/power	0.100mm	0.075mm
M	Min core thickness signal/signal	0.150mm	0.100-0.075mm
N	Core thickness (buried-multilayer)	Min 0.40mm	Min 0.30mm
		Max 0.80mm	Max 1.4mm
	Copper thickness plated through hole	15µm	13µm
	Copper thickness buried hole	15µm	13µm
	Copper thickness microvia	10µm	8µm
	Basis materials	FR4	FR4 Tg > 160°C
	Material for HDI-layer	RCC, FR4 liquid dielectricum	RCC, FR4 liquid
			dielectricum, with
			higher TG
	Number of HDI-layer	1 of both sides	2 of both sides
	Board construction	Symmetrical	Symmetrical

Figure 1 Dimensions for constructing HDI cards

These design rules are intended to offer a common standard for microvia technologies. Designers employing this common standard will now be able to source boards from a variety of European manufacturers adhering to the new criteria.

The group decided to establish fundamental design rules for the Standard HDI. These rules reflect the capabilities of each member of the working group. In addition, the group has established a second column of "high standard" design rules.

Companies requiring copies of these special design rules should contact any of the member companies in the working group.

Future updates for both sets of rules are likely.

Book-to-bill

The VdL book-to-bill ratios are given in Figure 2 for December 1997-November 1998.

Figure 2 VdL-book-to-bill verhältnis (ratios) December 97-November 1998