Technical Terms of Delivery for products and services

1. Products

Our product range includes single-, double-sided and through-hole PCBs, multilayers with up to 24 layers as well as semi-flexible PCBs from prototypes to (large) series.

For medium and large series of up to 25 m² per order, we offer an express service that can be implemented as follows:

*Standard: 1-4 layer circuit board in hot air leveling technology, solder mask, material FR4, conventional drilling techniques Our service begins with technical support and continues through to integration into our customers' supply chain management. We take every unique specification and individual requirement into account. Below we always differentiate between three performance categories: standard, special and technical limit.

2. Data

Our CAM employees ensure the implementation of your layouts through to the finished circuit board.

You can send us your production data in the following formats:
Layout data

• Extended Gerber 274x (standard)
• Eagle (default)
• Gerber 274
• ODB++

Drilling and milling data

• Excellon (standard)
• Drill file in Sieb & Meyer format 3000

Mechanical drawings can also be submitted in HPGL or DXF format.

If you cannot generate the files in the formats described, please contact our sales team.

3. Design Rule Check

All data supplied to us is checked for manufacturability using a standard design rule check and customer-specific DFM functions. If this is not the case, we will contact you immediately.

4. Quality

4.1. Quality standards

We manufacture PCBs in accordance with the IPC-A-600 Class 2 or Class 3 standard. In addition, we can also produce according to the following standards:

• PERFAG 1
• PERFAG 2
• PERFAG 3
• IPC-SM-840
• IPC-R-700
• IPC-A-600
• IPC-6012
• IPC-2221

4.2. quality assurance

We meet the UL® standards and the RoHS guidelines and are certified according to DIN EN ISO 9001. Production parameters, production conditions and raw materials are evaluated and registered using calibrated measuring devices.

The circuit boards are subjected to the following tests during the production process to ensure perfect quality:

• Non-destructive testing – For automatic and optical testing, we adhere to the IPC-A 600, Class 2 guideline. Specific testing procedures can be adapted to other specifications at any time if necessary.

• destructive testing
  • micrograph creation,
  • adhesion test,
  • Delamination test (multilayers are regularly subjected to thermal shock tests).

• Documentation of the parameters – Automatic recording and storage of the following parameters for at least 10 years:
  • production parameters,
  • quality-related results,
  • Time recording, including the respective employees.

• X-Ray – X-ray fluorescence spectrometry for layer registration and layer thickness measurement.

5. Electrical testing

During the final electrical test, circuit boards are checked for interruptions and short circuits.

The client's Gerber data is loaded into our testing system, from which a netlist is generated that contains all of the identified test points. By default, these test systems test according to the following criteria:

• for interruption if > 10 ohm network resistance is determined
• terminated if resistances < 10 MegOhm are detected between independent shunts

We use the following test systems:

• Test adapter/parallel tester

Using the test program, adapter plates are drilled and equipped with test needles, which are deflected onto the relevant contact points in order to simultaneously record all end points of the electronic network for the test process for connections and interruptions. At the same time, all networks are checked against each other. The test result is then compared with the electrical network list.

• Finger tester (flying probe)

Alternatively, the electrical test can be carried out using a finger tester. The contact points of the circuit board are contacted sequentially using contact needles based on the underlying netlist and tested for connection and interruption. Measuring needles hang on mechanically movable “fingers” that move to the previously programmed test positions. During all test procedures, the circuit boards on which a short circuit or an open circuit has been detected are automatically separated from the circuit boards that have been tested to be clearly defect-free. For faulty or unclearly tested circuit boards, an error log with the exact error location is created. After successful troubleshooting, the circuit board is subjected to a complete test run again.

6. Materials

6.1. Laminates (base material)

We process base materials in thicknesses from 0.5 mm to 3.2 mm.
Other qualities are available upon request, for example materials with tracking resistance values ​​(CTI) up to 600 volts.

The following values ​​apply to a material thickness of 0.5 mm or more:

6.2. Copper foil thickness standard (before galvanic copper plating)

6.3. Copper clad laminates

If you would like other materials, please contact our sales team.

7. Tolerances for twist and warp

Please note that the warping value increases above average if the copper distribution on the circuit board varies greatly locally. Especially with multilayers, a symmetrical layer structure should be planned right at the beginning of layout development. With asymmetrical material structures, the different tensions of the glass fabric qualities can result in higher torsion and warping values.

8. Available manufacturing benefits

In order to produce economically and sustainably, we check the best possible utilization of our production panels and compare them with the most commonly used PCB sizes in order to avoid unnecessary waste.

9. PCB thickness

We can process different PCB thicknesses regardless of the number of layers.
However, the lead times for special material thicknesses can vary if the desired material is not in stock.

10. Multilayer layers and structures

We produce multilayers with up to 24 layers. The layers can then be connected to one another via plated-through holes between the outer layers (vias), from an outer layer to an inner layer (blind vias or blind holes) or between the inner layers (buried vias).
You can find the most frequently used layer structures on our website in the Download Center.
Of course, if you have any questions, you are welcome to contact our sales team directly. We will be happy to send you special layer structures upon request.

11. Ladder diagram creation

The technical limit for the lithographic resolution of our exposure systems when creating conductor patterns is 50 μ conductor track width (track) and gap. The higher the final copper thickness, the higher the degree of undercutting on the flanks, which must be compensated for in the exposure parameters.

We would be happy to advise you personally regarding the reproducibility of your layout, as the strength of the copper structure can be limited by the layout design and the process technology of solder mask printing. When it comes to solder mask coating, we pay particular attention to covering, under-covering or even exposing the conductor flanks and insulation surfaces.

12. Solder mask

In the phototechnical solder mask process, the surface is embedded in a photosensitive polymer. The chemical crosslinking of the polymers is achieved through defined exposure; All non-exposed zones are developed with sharp contours, even in the micrometer range. In order to achieve the required electro-physical properties of the paint, a UV bump is then carried out, essentially a “vitrification” of the paint surface to reduce ionic contamination, and final thermal curing.

When coating the solder mask, the solder pads of the via holes can be printed closed if desired. However, this cannot guarantee that the via holes will be closed (via plugging) (unsuitable for vacuum testers).

However, if it is absolutely necessary to close the via hole, this process is carried out in a separate process in which the holes in question are specifically coated with paint and closed.
Closing with standard paints is possible up to a hole diameter of 0.45 mm. For larger hole diameters, a special varnish or resin filling is required.

12.1. Parameters of solder masks

We only use epoxy resin-based solder masks, as these also improve the tracking resistance on the surface of the circuit boards.

*Minimum distance between soldermask-free areas in order to be able to reproduce a soldermask bridge

When creating solder masks, solder stop clearances must be taken into account in a ratio of 1:1 to the pads, i.e. without oversizing. We calculate the expansion required for production ourselves. The following solder mask colors are possible:

• green (default)
• blue
• black
• red
• white

TOP/BOTTOM can be painted differently.

13. Electroplating copper deposition process

The thickness of the copper plating depends on the exposure time and the current in the electroplating bath. Basically, during the process, a deposit of 20 μ to 25 μ of copper is applied to the surface and in the holes to be plated through. Thicker copper layers are possible by adjusting the process parameters or additional galvanic processes.

In order to achieve uniform copper deposition, when designing the layout, it should be taken into account that conductor track structures are either not embedded in ground at all or are completely embedded in ground. The conductor track guides or pad positioning should be centered within a ground embedding and at equal distances from each other. If copper structures are distributed unevenly in the layout, over-deposition tends to occur in the “low-mass” regions. This leads to a reduction in the spacing of the conductor tracks up to electrical failure due to a short circuit, as the conductor tracks literally grow together.

13.1. aspect ratio

The “Aspect Ratio” defines the ratio of “material thickness to hole diameter”.
It is determined as follows: material thickness divided by the smallest hole diameter.

Example: 1.6 mm material thickness divided by 0.2 mm hole diameter = 8

The performance of electrolytic copper deposition is expressed in the aspect ratio, the ratio of the diameter of a hole to the contactable depth of this hole.

This value is very crucial for the manufacturability of the circuit board, because the larger the aspect ratio, the more complex it is to produce metallization in the holes.

13.2. Microfilling (Via-in-Pad)

This technology enables the simultaneous filling of blind vias and the reinforcement of the through holes.

With HDI circuits there is usually not enough space left to route the signals to different positions via through holes. A space-saving solution is to position blind vias in SMD pads, which are filled with copper after drilling. Due to this filling, only a very small amount of solder flows into the remaining “surface dimple” and enables a proper soldering joint. The maximum drilling diameter and depth is 0.15 mm.

13.3. Via plugging via resin filling (also suitable for via-in-pad technology)

Closing both continuous and blind vias with resin combined with subsequent overmetallization is an alternative to microfilling, but this process is more complex in terms of process technology.

The advantages over microfilling are that

• Through holes from 0.1 mm to 2 mm can also be closed; However, the material thickness must not be smaller than the drilling diameter.
• a planar closing of the holes is possible; no dent (dimple) remains in the pad.

14. Surface finishing

We can currently create the following finishes for you:

• Hot air tinning lead-free (HAL) – Sn / 0.3 Ag / 0.7 Cu / 0.02 Ni
• Electroless Nickel Gold (ENIG) – 99.9 Au
• Electroless nickel palladium gold (ENEPIG)
• Chemical tin (chemical Sn)
• Chemical silver (chemical Ag)
• Organic tarnish protection (OSP)
• Electroplated nickel gold (hard and bond gold) – hard 99.8 Au / soft 99.99 Au

Properties of the different end surfaces:

15. Printing techniques

15.1. Serialization

In order to ensure that circuit boards can be clearly identified, individualized labeling of the individual circuit boards within a series can also be selected. This marking is applied automatically (direct exposure of the structures or assembly printing) in white color and can be composed of static information (e.g. production dating, date code, etc.) and consecutive numbering in chronological order and can be displayed in machine-readable format in the following formats:

• 1D & 2D barcodes, data matrix, QR codes.

15.2. Marking printing/assembly printing

In order to avoid interruptions or obfuscations within the typeface, the line width of the marking print should not be less than 130 µ and the font height should not be smaller than 1000 µ. The soldering surfaces should be freed from the marking print for at least 250 µ all around, otherwise an unclean print image and the soldering surfaces being pressed are possible.

15.3. Carbon print

15.4. Peel-off varnish

The layer thickness of the peel-off varnish is approx. 500 µ.

Holes that are covered with peel-off paint should not exceed 1.8 mm in size.

*Complete spanning of the hole cannot be guaranteed

16. Contour processing

We drill, mill and score your circuit boards according to your specifications and wishes. The type of mechanical processing depends on your individual specifications. In our drilling and milling center we work with modern, fully automatic CNC drilling and milling machines. These techniques enable machining within the DIN 7168 “medium” (medium accuracy) and “fine” (precise accuracy) standards.
If non-plated holes are positioned in a soldering eye, this must be at least 500 µ larger than the hole. Otherwise, solder pads may be removed.
If there is no information about the type of holes for plated-through circuit boards, we determine independently to the best of our knowledge which holes are plated through and which are not plated through.
If drilling or dimension plans are provided that do not correspond to the drilling programs or the contour according to the layout data, the drilling programs and the contour according to the layout data are binding for production in any case.

Unless otherwise stated, the center point (= center vector) of the contour lines in the layout data is decisive for the contour of the circuit board. If slot millings (slots) are represented by rectangular contours, we assume that the corner radius is included.

Depending on the size of the circuit boards, the following tolerances are specified (other tolerance values ​​are possible by agreement):

• Scoring (notch milling)

The angle of the scoring knives is 15°. Therefore, along the contours that are scratched, a distance between the conductor tracks and the contour must be taken into account according to the following table:

If no plus tolerance is permitted for the contour, the desired minus tolerance must be added to the “distance between conductor tracks and contour” values ​​mentioned above.
Example: PCB format 100 mm x 100 mm +0.0/-0.30 mm Distance between conductor tracks and contour with 1.6 mm material thickness: 0.5 mm + 0.15 mm = 0.65 mm

• Milling

As an alternative to scoring, we offer contour milling. The advantage over scoring is that the outer contours are processed in the most special shapes and cutouts such as round, oval, wave shape, zigzag, etc. Please note when milling:

• If the delivery is to take place in milling form, a distance between the circuit boards of 2.0 mm is sufficient as standard in order to be able to place milling bars between the individual boards.
• If the delivery is not to take place in a panel, a distance of at least 8.0 mm from board to board must be taken into account in order to ultimately be able to separate the circuit boards.

• Deep milling and drilling / countersinking holes

Milling and drilling with a defined Z axis is carried out according to your drawing specifications. Countersinks are manufactured with 45° or 30° as standard. The specifications for this can be set individually.

• Milling and scoring combination

In some cases it makes sense to combine both milling and scoring to achieve the best compromise between cost and material loss. Our CNC machines are able to implement these combinations precisely.

• Chamfers

For easier installation of plug contacts (e.g. PCI plugs), edge chamfering of 45° or 30° at different depths is possible.

• Edge metallization

In order to realize flank contacts, we can produce special edge metallization (e.g. side plating or castellated holes). This is particularly useful when improved electrical conductivity or shielding is required.

• Semiflex

With semi-flex technology, a defined area of ​​rigid circuit boards is milled down to a remaining material thickness in order to be able to bend the material there. Although the same bending angles and radii cannot be achieved compared to rigid-flex circuits, they are often sufficient for the applications. The semi-flex technology allows bending three to five times, depending on the construction; The circuit board must therefore be statically mounted.
The main advantages lie in the cheaper production and the elimination of the otherwise necessary polyimide film, which in turn would require thermal pretreatment due to the high moisture absorption.

17. Drilling and milling tolerances

*Please note that plated holes typically need to be drilled or milled 150 μ larger than the desired final diameter to compensate for the metallization in the hole. For example, if you want a final diameter of 0.6 mm, the diameter of the drill used is 0.75 mm unless different tolerances are specified.
**depending on the hole diameter
***provided that the drilling process is carried out in a machine clamping (tenting)

18. Storage

18.1. humidity

Due to the epoxy resin in the base material of the circuit boards, they (especially multilayers) are extremely hydrophilic; that is, the water molecule dissolved in the air is absorbed by the material. Depending on the environmental conditions, moisture balances are established in materials. Under storage conditions of, for example, 20 degrees Celsius and 35 percent humidity, a moisture absorption of 0.12 percent (in percent by weight of the epoxy resin) can be recorded after just 12 days. What is crucial here is that as moisture absorption increases, the gas pressure within the circuit board also increases, which is caused by the high temperatures during the soldering process. If the moisture absorption exceeds 0.17 percent, a critical gas pressure of 8 - 10 bar is reached, at which delamination and bubble formation can occur. Epoxy resin can absorb up to 0.5% moisture by weight.

To ensure that the moisture content and adhesion of the material are perfect, we carry out a delamination test using a test specimen after the circuit boards have been completed.

To further avoid or reduce moisture absorption, we strongly recommend the following points:

• Warehouse environment

PCBs should be stored in a constantly heated environment under controlled conditions until shortly before soldering/processing, preferably in darkened rooms. Due to climatic changes, a controlled storage environment is becoming increasingly important to maintain the quality of the circuit boards. Humidity and temperature fluctuations should be minimized and the packaging of the circuit boards should be checked for integrity before processing. Storage is preferably carried out in closed containers. We would like to point out that there is no reliable protection against moisture due to the gas permeability of polyethylene bags. To improve protection, we also offer to vacuum-pack the circuit boards in a DRY-SHIELD protective bag with an indicator and dry bag. The protective films/bags should only be removed shortly before soldering/processing. We recommend vacuum sealing remaining quantities again, or at least sealing them securely with adhesive tape or by clamping the foil between the circuit boards and storing them in boxes to avoid drafts.

We strongly recommend that you maintain the following conditions in the storage environment to minimize moisture absorption:

• Room temperature 18-20°C
• relative humidity < 50%

• storage time

The storage time of circuit boards should be as short as possible and consumption should follow the “first-in, first-out” rule. For storage times of over 3 months (based on the production period), it is difficult to predict at what point moisture absorption can lead to problems during soldering/processing due to a wide variety of influencing parameters such as layout, layer structure, etc. To ensure reliable proof of the storage time, we can apply a production date/date code to the circuit boards upon agreement. Please note that the storage life also depends on the final surface chosen. Guidance values ​​can be found in the Surface Finishing section of this document. Please always use opened packages first.

18.2. Solder test

Circuit boards that have already been stored for several months and whose transport conditions are unclear (transport of goods by freight forwarders in all weather and temperature conditions) should definitely be subjected to a soldering test before further processing.

18.3. Preconditioning/drying

To reduce the moisture absorbed, regardless of the outcome of a soldering test, we recommend drying the goods in an oven, with the circuit boards preferably dried vertically in a rack.

If drying is possible in a vacuum oven at 50 mbar, the temperature can be reduced by approximately 20 °C and the time by approximately 30 minutes. This process is advantageous for the sensitive “chemical tin” surface. It should then be determined using a few test specimens whether the solder is still wetting sufficiently; otherwise the chemical tin must be refreshed.

After drying, processing of the circuit boards should begin immediately as the hydrophilic properties of the circuit board remain. The time between the different soldering processes must be kept as short as possible and should not exceed 8 hours. This is the only way to avoid excessive moisture absorption in unprotected material. Dried and tempered circuit boards will briefly become saturated with water from the ambient air.

18.4. Product-specific requirements

The values ​​mentioned in the previous sections are guide values. The values ​​do not fully take into account the different processing parameters and product-specific properties of the individual circuit boards and must be determined by the respective processor on a product-specific basis:

• The different soldering processes and profiles cause different stresses. The thermal load in convection ovens is not as high as in infrared ovens or steam phases.
• If the recommended storage conditions cannot be consistently maintained, the material will absorb more water than is possible under constant conditions. Packaging in DRY-SHIELD protective bags can help here.
• if the layout contains large, closed copper surfaces, moisture will require a longer period of time to escape.

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