ro4350b pcb

Rogers 4350b Laminates Dielectric Constant

The Rogers ro4350b offers great high frequency performance coupled with circuit fabrication of low cost. This laminate has low dielectric tolerance and loss. This offers great electrical performance and permits applications working with higher frequencies.

Asides from this, the Rogers 4350b has controlled impedance, as well as repeatable design to suit transmission lines. With this, the Rogers 4350b is great for all broadband applications. Asides from this, the design of the Rogers ro4350b offers great dimensional stability. You can go through the ro4350b datasheet to learn more.

Properties of the Rogers RO4350B Material

Here, we will be considering the major properties of the Rogers ro 4350b material. These include:

Low insertion loss and dielectric loss

With low insertion loss, it is possible to use ro4350b core in different applications whereby higher frequencies for working restricts the standard use of PCB laminates.

Among all other printed circuit board laminate materials, they have the least thermal coefficient of dielectric constant. Moreover, the Rogers 4350 dielectric constant is steady with respect to a wide range of frequency.

Insertion loss is greatly reduced due to the use of the LoPro copper foil by Rogers in the ro4350b laminate. This makes sure that it qualifies as an appropriate Rogers substrate for use in broadband printed circuit board applications.

Great dimensional stability

The Rogers ro 4350 laminate’s CTE offers some benefits to PCB designers. This type of rogers laminate comes with a similar coefficient of thermal expansion to that of copper. This helps it display great dimensional stability.

The dimension stability of PCB materials is a very important property in constructing mixed dielectric Rogers PCB with multiple layers.

Electrical properties are Steady against Frequency

This stability ensures transmission lines having controlled impedance, as well as a filter design that is repeatable.

CAF Resistant

Anodic filaments that are conductive have to do with the failure mode present in any circuit board. This happens under gradients of high voltage as well as high humidity.

Z-axis CTE is low

With glass transition higher than 280 degrees Celsius, the expansion attributes of the laminates stays steady all through the temperature range of the processing of the circuit.

 

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Compatible with the FR-4 Processing Standard Methods

Rogers ro4350b Circuit Board

It is very easy to fabricate this laminate into a printed circuit board applying the processing methods of the traditional FR-4. The price of the Rogers ro4350 is the most competitive compared to other laminates of the RO4000 series.

Rogers 4350 Applications

The Rogers 4350 can be useful in these equipment and systems. These include:

  • Computing devices
  • Backhaul Radios
  • IP Infrastructure
  • Power Amplifiers
  • Small Cells
  • Measuring and Test Equipment
  • Communication Systems

Recommended Type of Copper Foil for RO4350b

Designs of copper foils for rogers substrates of high frequency helps then in offering great performance in extreme reliable applications of printed circuit boards. There are different types of copper foil in different weights/thicknesses.

The characteristics of these copper foils also differ. This is why it is important that these differences are well understood to guarantee the appropriate choice or option for every environmental condition or use. Below are two major copper foil types utilized in the ro4350b laminates.

LoPro foil

With this copper foil type for the materials of rogers 4350b, you should apply an adhesive layer that is thin on the copper’s treated surface. Also, it incorporates a material of adhesion enhancement. Just like the reverse treated copper, a bonding exists between the adhesive surface (treated) and the dielectric layer for a superior and better adhesion.

Electrodeposited Copper

Electrodeposited copper manufacturing has to do with copper ions deposition via electrolysis onto a metallic spinning mandrel in creating a foil layer that is thin.

This process leads to thin high purity foils that are great for use in applications requiring high frequency. Electrodeposited copper goes through several treatments that help in improving the adhesion present between copper and dielectric layers during the copper-clad lamination process.

Moreover, this treatment serves as an anti-tarnish agent, thereby reducing the pace of copper oxidation.

RO4350b Dielectric Constant

The rogers ro4350b dielectric constant is 3.48 +/- 0.05. Its Df ranges from 0.0031 – 0.0037, which can work with frequencies of about 40 GHz. This can help in developing microwave and RF circuits, matching controlled impedance and network transmission lines.

The laminates of RO4350B offer strong control on the dielectric constant. It also maintains a low loss coupled with using the same method of processing as standard glass/epoxy.

Rogers 4350b and FR-4 – What’s the Difference?

Now, let’s take a look at some major differences between the two substrates: Rogers 4350b and FR-4.

Price

Concerning the cost of the FR-4 and Rogers 4350b, there is a great difference. That of FR-4 is cheaper compared to the Rogers 4350b laminate.

Performance

The Rogers 4350b boasts better performance when compared to the normal FR-4 printed circuit board materials.  Despite this, both substrates have similar assembling and processing costs.

Dissipation Factor

The dissipation factor of FR-4 materials is usually high when compared to that of the Rogers 4350b. As frequency increases, the dissipation factor also increases. The Rogers 4350b laminates of high frequency usually show a stable dissipation factor with frequency.

Rogers laminates’ low dissipation factor is vital to reduce signal losses. In addition, their assembly compatibility and automated processing ensures easy fabrication of construction.

High Frequencies

Although FR-4 is great due to their reliable electrical and mechanical properties and low cost, it is not appropriate for laminate applications of high frequency.

Thermal Management

PCB materials that are based on thermoset such as the 4350B laminates are largely robust compared to the FR-4 laminates. They are also famous due to their very high handling of temperatures.

Concerning thermal management, the rogers 4350b material works better as a result of its lesser variations compared to the FR-4 laminates.

Impedance stability

Majority of applications requiring high-frequency must work with stable impedance. This is where the FR-4 types and Rogers laminates differ largely.

FR-4 substrates have wide variations in dielectric constant across the width and length with temperature changes. Rogers substrates, on the other hand, feature more extensive range of dielectric constant.

In general, the Rogers 4350B laminate features a high dimensional stability in comparison with FR-4 laminates. This means that, the right choice is laminates with high frequency, if you require a printed circuit board having minimal variations all through the wide changes in temperature.

You should go for the Rogers 4350b substrate whenever majority of your applications have to do with conditions requiring high temperature.

Processing Guidelines of the Rogers ro4350 Circuit

The following guidelines will give you some basic info on how to process multi-layered or dual-sided printed circuit board making use of 4350B laminates.

Preparation of the Inner Layer

Tooling

The Rogers ro4350 laminates work with majority of pinned and pinless tooling systems. Your eventual registration specifications, preferences, and PCB manufacturer’s capability, will go a long way in determining if you should apply any of these:

  • Standard or multiline tooling
  • Round or slotted pins
  • External or internal pinning
  • Post-etch or pre-etch punching

Most times, multiline tooling, post-etch punching, and slotted pins satisfies majority of requirements.

 

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Preparing the surface for copper etching and photo imaging

Based on the core thickness of the Rogers ro4350, you can make the copper surface for the photoresist processing. This is possible making use of the chemical and mechanical procedures.

Prepare the thinner cores making use of the chemical procedure. This includes micro-etching, washing, water rinsing, as well as drying operations.

The thicker Rogers ro4350 materials work well with the scouring systems (mechanical type). Moreover, the Rogers ro4350B laminates work with most of the liquid and dry film photoresists.

Once patterning is completed, you can go ahead to process them.

Oxide Treatment

The Rogers ro4350B cores can be processed making use of oxide or copper oxide. However, the best you should choose is that usually suggested in the guidelines that back the selected prepreg or adhesive system.

Multi-Layer Bonding

The Rogers ro4350 substrates work fine with many thermosetting and thermoplastic adhesive systems. Moreover, make sure you consider the guidelines for the specifications of the bond cycle.

Drilling

Considerations for drilling

You can make use of standard entry (aluminum or thin and pressed phenolic) and exit (pressed phenolic or fiberboard) materials whenever you are drilling the Rogers ro4350b cores

This Rogers laminate works fine with many drilling parameters. However, avoid any drilling speed that is higher than 500 SFM (surface feet per minute).

For mid-range and large diameter tools, the chip loads may be higher than 0.0002”. Another great advice here is the application of lower shiploads for the small drills in diameter (<0.0135”).

Generally, the best bet is to apply the geometry drills rather than work with undercut styles. This is because they get rid of debris from the holes more efficiently during drilling.

Also, don’t base the hit count on the appearance of the tool. Rather, base it on the plated inspection (thru-hole). The Rogers ro4350b materials drilling leads to acceleration at which the drills wear. However, the hole wall’s quality is determined by the size distribution of the ceramic powder and not via the drill cutting edge.

Be prepared to see roughness on the hole wall. This spans from 8 to 25 mm. Also, make sure that this stays constant from your first ever hit to a few thousand hits.

PTH Processing

Preparation of the surface

Multilayer and two-sided constructions can be processed making use of debur systems that are conveyorized, which works with nylon brushes (oscillating) for the copper surface.

Generally, make sure you take a look at the Rogers ro4350b laminate’s thickness, as well as the registration requirements whenever you are choosing the best surface preparation and deburring method.

Drilled holes desmearing is usually not necessary for Rogers pcbs with two sides. This is because the high temperature of the resin system helps in reducing the smear occurrence.

There may be a need for the multilayer rogers ro 4350b boards to desmear. This has to do with the prepreg’s requirements.

Deposition of Metal

The Rogers ro4350b laminates usually don’t require any special treatment before the metallization process.

Asides from this, they work with direct colloidal deposition, as well as processing of electroless copper. For circuit boards that feature PTHs having an aspect ratio that is high, you may think of the copper plate (0.00025”).

Processing of the outer layer and copper plating

The Rogers ro4350b substrates work with panel and pattern processing. They achieve this by making use of the standard tin/lead, electrolytic tin, or plating from acid copper. After plating, the laminate can be processed by applying any of the conventional strip, etch, or strip (SES) processes.

Make sure that the Rogers 4350b material’s post-etch surface is preserved. This guarantees the best bonding with directly screened and photo-imageable solder masks.

Final Finishes of the Metal

The Rogers ro4350B laminates work fine with HASL, OSPs, and chemically deposited or most electrodeposited finishes.

PCB individualization makes use of high frequency laminates from Rogers, like the Rogers 4350 may be achieved via dicing, sawing, routing, shearing, and punching.

You may utilize V-scoring and breakaway tabs to achieve individualization of the circuit board after the automated assembly.

Rogers RO4350B Shelf Life

The Rogers ro4350b laminates can be stored for long periods if kept under room temperature (13 to 32 degrees centigrade) and humidity levels.

Its dielectric materials stay inactive to exposure to high humidity. However, exposure to high humidity can lead to the oxidation of metal claddings such as copper. You can get rid of the oxidation present on copper. This is achieved by making use of the micro-etch process.

Rogers RO4350B Material Quality Standards

Below are the important quality and safety standards the Rogers ro4350B laminate has to comply with.

  • UL Standard
  • ISO Standard
  • CE Standard
  • REACH Standard
  • IPC Standard

Conclusion

We have created enough information in this guide on the Rogers ro4350B. You should have no problems if you choose this high-performance material. If you have any questions, feel free to contact us. We are here for you.

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