1. Introduction

The world is divided into a part that works with the Metric system and a part that works with the Imperial system for defining measurements. The “µm” is 25.4 times smaller than the “Mil”. Dimensions for electronics are driven smaller all the time. To ensure the highest quality possible, we decided many years ago to work exclusively in the Metric system in our front end department. Therefore the basis of all measurements given in this document and in our website is the Metric system. All Imperial values are there for clarification and general understanding only.

2. Board dimensions

 

The maximum surface for a single PCB or a customer panel in our pooling services is limited to 8.75dm², except for IMS pool. See our BLOG on large boards and pooling. The minimum dimensions for a single PCB depend on the specific service and are 5mm x 5mm (0.200” x 0.200”) in general with the exception for “PCB proto” where the minimum is 20mm x 20mm (0.788” x 0.788”).

3. Base material

For all our services we use RoHS-compliant base materials. In addition our base materials are specially selected to withstand the more severe lead-free soldering temperatures. For our “PCB proto” and “STANDARD pool” pooling services we only use MID Tg (TG145-150°C) improved FR-4 materials (for example Isola IS400 and Nan Ya NP155). In “STANDARD pool” we offer also higher Tg materials in non-pooling. Other materials are available in our RF pool  and IMS pool service.

You can find out which material is used for your order on the PCB Passport available in your account (running orders or view history)

4.1. Standard copper thickness

Pooling services – “PCB proto” and “STANDARD pool”:

For outer layers of PTH boards till Pattern cllass 6 we use a standard copper foil of 18µm/½oz base copper. Over this we plate 20 – 25µm (+½oz) of copper so the final thickness is equivalent to (just over) 35µm/1oz copper. In “STANDARD pool” you can also specify a thicker copper foil prior to plating; For inner layers the standard copper foil thickness is 35µm/1oz. Inner layer copper is not plated up so the final thickness is the foil thickness. For boards with higher classification we start with 12 µm baze copper. The select classification wizard in PCB Calculator will guide you.

Pooling service – “IMS pool”:

We use 35µm/1oz foil

Note: the maximum copper thickness that can be used depends on the pattern classification of your board and vice versa (see table in note 4.2).

4.2. Option 35µm/1 oz, 70µm/2 oz & 105µm/3 oz base copper foil.

Pooling service – “STANDARD pool”:

Thicker base copper foils (35µm/1oz and 70µm/2oz) are available for 1L and 2L boards.  The base copper thickness affects the minimum pattern class of the board. (See table below)

Non-pooled service “STANDARD pool”:

A full range of  base copper thicknesses are available subject to corresponding pattern values: 12µm/⅓oz, 18µm/½oz, 35µm/1oz, 70µm/2oz and 105µm/3oz.

 

Base Cu OL

OTW

OTT-OTP-OPP

Base Cu IL

ITW

ITT-ITP-IPP

12µm/⅓oz

0,090mm/3.5mil

0,090mm/3.5mil

12µm/⅓oz

0,090mm/3.5mil

0,090mm/3.5mil

18µm/½oz

0,100mm/4mil

0,125mm/5mil

18µm/½oz

0,100mm/4mil

0,100mm/4mil

35µm/1oz

0,150mm/6mil

0,200mm/8mil

35µm/1oz

0,150mm/6mil

0,150mm/6mil

70µm/2oz

0,200mm/8mil

0,250mm/10mil

70µm/2oz

0,200mm/8mil

0,250mm/10mil

105µm/3oz

0,250mm/10mil

0,300mm/12mil

105µm/3oz

0,250mm/10mil

0,300mm/12mil

5. Surface finish

Our pooling services offer two RoHS-compliant lead-free finishes: electroless nickel immersion gold (ENIG or Ni/Au) and lead free hot-air levelling (LF HAL).

For customers who want the best price for prototype boards and are not concerned about the surface-finish we offer the option “Any lead-free”. This means that we pick the surface finish which gives the best utilisation of our pooling panels on the day and hence the lowest possible price.

The option “Any lead-free” is the only available option for the “PCB proto” service and is the Eurocircuits default for the “STANDARD pool” program. To pick a specific finish, please go to the “technical specifications” menu and choose a finish from the options menu.

6. Solder mask

We only use Liquid Photo Imageable soldermask. This is available as default in colour green, but as an option also in other colours. Choosing a blue or black soldermask affects the shortest available delivery period on the “STANDARD pool” service.

7. Extra

As extra options we offer:

  • Gold fingers: this means galvanic/hard gold-plated edge connectors (“STANDARD pool” )
  • Carbon pads: these are carbon ink printed pads for keyboards or similar applications (“STANDARD pool”)
  • Peelable mask: blue peelable mask for protecting PTH holes during wave soldering (“STANDARD pool”)
  • Via filling: closing the vias by double solder mask printing over the vias (“STANDARD pool”)

8. Legend

For most “PCB proto” and “STANDARD pool” services we offer white legend printed on a digital legend printer. This brings more flexibility and speeds up the process to ensure timely deliveries.

Otherwise we use screened Liquid Photo Imageable Legend ink. The default colour is white but as options we offer other colours as well. Choosing different colours on both sides of the board will result in extra costs.

9. 1. Minimum finished (final) hole size

On both the “PCB proto” and the “STANDARD pool” services the minimum finished hole size is now 0.25mm = 0.010” for pooling We recommend the use of 0.30mm = 0.012” diameter vias. Smaller diameters down to 0.1 mm are available but cannot be pooled.

By default, all holes equal to and smaller than 0.45mm = 0.018” are defined as via holes. According to IPC rules, via holes have no negative tolerance on diameter. To keep prices down and solve annular ring problems in your design we will use this to reduce the number of via tool changes on the production panels. In our new PCB Calculator you can define another value for the largest via hole diameter. ( Holes <= may be reduced). Setting this parameter to a lower value then 0.45 mm will prevent we reduce component holes  smaller or equal to 0.45 mm.

In the “IMS pool” service the minimum hole size is 0.6mm due to drilling in aluminium.

The minimum hole size affects the maximum board thickness that we can achieve. See classification table for detailed info.

9. 2. Minimum annular ring

Good PCB plating, soldering and appearance (no breakout) require the specified minimum annular ring of copper around each hole. To calculate the minimum annular ring take the finished hole size and add a value to accommodate the hole-wall plating and manufacturing tolerances: 0.1mm (4mil) on holes up to 0.45mm (18mil) in diameter and 0.15mm (6mil) on larger holes.  This gives the production hole size.  The annular ring value is half the difference between the pad size and the production drill hole size. In the table above (page 2) we show this (plating thickness + annular ring) as a single figure to be added to the desired finished hole size. Annular ring compliance is one of the checks performed in PCB Checker

9. 3. Minimum pattern & drill class overview

See our classification table

10. Slots and cut-outs

Terminology.

We use “routing” or “break-routing” to refer to external profiling, and “slots”, “milling” and “cut-outs” to refer to internal cut-outs. Specify slots, internal milling and cut-outs with their finished dimensions (widths and lengths) to ensure that they are produced correctly.

External profiling.

This can be shown on the copper, mask or legend layer or on a separate mechanical layer.  It is important to make sure that there is only one profile shown.  If you want a circular board, please show a circular profile and not a circle within a square box.

Internal slots and cut-outs.

For maximum accuracy, please indicate slots, milling and cut-out information clearly in a Gerber mechanical layer, showing the border of the PCB, the internal slots, milling, and cut-outs. Indicate in text the size of the slots with tolerances (if needed) and whether plated or not. Do not indicate these features in copper layers or by text outside the layout.

For the “On demand” service only you can use a separate text-file in English language, a drawing or a document.  Include the text-file, PDF or HPGL file in the WinZip file that contains your layout data.

11. Delivery panels/customer arrays

11.1. Customer-panelised data

  • Maximum panel dimensions: 250 x 350mm = 9.84” x 13.78” – maximum surface of the panel is 8.75 dm2
  • Minimum borders to give a stable panel: 2 x 5mm = 0.2” in X & Y.  Allow an extra 2mm (0.079”) between the edge of the panel and the edge of the circuit for the cutter path if the panel is to be break-routed (total border = 7mm (0.28”)).
    Panels drawn without a border are evaluated to check the panel stability.
  • Minimum clearance between PCBs for break-routing: 2mm (0.079”).  Any larger value is OK
  • If you require V-cut scoring, we advise to use the “Panelised by Eurocircuits” option for technical reasons.
  • Break-out routing tabs will be defined by our engineers to ensure a stable panel. Rout tabs will be drilled to break inside the board profile for clean break-out.
  • All fiducials (e.g. for mounting SMD components) and external tooling holes must be included in your data.

Please consult our guidelines to make panels

 

11.2. Panelised by Eurocircuits to Eurocircuits rules

  • One type of circuit only.  For multiple panels please supply pre-panelised data.
  • Minimum dimensions of the single circuit are 5 x 5mm = 0.2” x 0.2”, except for “PCB proto”: 20 x 20mm = 0.197” x 0.197”
  • Maximum panel dimensions: 250 x 350mm = 9.84” x 13.78” – maximum surface of the panel is 8.75 dm2
  • Minimum border to give a stable panel: 2 x 5mm (0.2”) in X & Y.  Select border width (5mm (0.2”) or 7mm (0.28”) or 10mm (0.4”)) from the pick-list “Panel Border” in the price calculator. The system will automatically add 2mm (0.079”) on all sides for the cutter path if the panel is to be break-routed.
    Panels without a border are possible but not recommended for stability reasons.
  • Minimum clearance between PCBs for break-routing: 2mm (0.079”).  Select clearance (2mm (0.079”), 5mm (0.2”) or 10mm (0.4”)) from the pick-list “Distance between two PCBs” in the price calculator.
  • No clearance between PCBs is required for V-cut scoring (but note that all lay-out elements and holes should be 0.45mm (0.018”) away from the edge of the board and that the minimum panel size is 100 x 100mm = 4” x 4”)
    • Break-out routing tabs will be defined by our engineers to ensure a stable panel. Routed tabs will be drilled to break inside the board profile for clean break-out.
    • Circuits cannot be rotated or nested.  If rotation or nesting are required, please supply pre-panelised data
  • Standard fiducials and tool-holes (3mm European and 0.125” US) are included in the panel border in each corner.  For special fiducials, please supply pre-panelised data.
  • For paste files see Note below.

Please consult our guidelines to make panels

11. 3. Panelised by Eurocircuits to your panel plan

We can also panelise to your drawings.  Supply the Gerber single image and a clear drawing in Gerber, PDF or HPGL format. We will handle up to 10 different circuit types per panel, plus rotation and nesting. Enter the circuit size, panel size and separation method in the Panel Specification menu and leave the border and spacing boxes at default.  For paste files see Note below.

Please consult our guidelines to make panels

 

Note on paste files:

We recommend that you supply us the paste file for the single image together with the rest of the Gerber data. If we panelise the job, we automatically panelise the paste layers. If no paste file is supplied with the original data, we will generate a paste file from the SMD pads on a “best efforts” basis. It is advisable to check this paste layer before submitting it for screen making. You can download the panelised paste files from the web site.

Detailed guidelines for designing and ordering customer panels are to be found on the home page under Panel guidelines

12. Traceability

To identify every individual customer order, all orders are marked with the Eurocircuits order number: e.g. E501225. The marking is done either in the solder mask or in the silk-screen (legend). We use this identification to track the circuits after they have been routed out of the production panels. The order number can be used to trace batch and date information via the website.

13. UL

UL marking is possible in all our service except for the “IMS pool” service. If your data is already set up for volume production needing the UL logo and you want to order “IMS pool” prototypes without the UL-logo, add a text file in your set of data and call this (empty) file NO_UL.txt.