If you are anything like me, you can never get tired of designing printed circuit boards. Among the fundamental aspects of PCB design includes your application area. It determines the materials and parts you must incorporate into the design. However, numerous materials can confuse even the best of us at times. Do you use a Taconic RF-30A, an Isola, or something else?
You do not need to worry; we will canvass everything you need to know about Taconic RF-30A, its advantages, application, typical values, etc., to help you decide during your design process.
Taconic RF-30A PCB
A Taconic RF-30A PCB implies a printed circuit board developed using an organic ceramic substrate or laminate reinforced with woven glass – RF-30A. You can hardly go wrong by picking this PCB when you want low-cost yet high-volume PCBs for commercial radio frequency and microwave applications.
It is a low-loss dielectric material or substrate with a low-profile copper foil. The low-profile copper ensures stable electrical attributes with enhanced PIMD levels. It also has a lower insertion loss, especially over a range of broadband frequencies.
You also get to enjoy other aspects of RF-30A laminates like lower CTE values, more rigidity which reduces the impact of other factors on the RF components. A crucial aspect of RF-30A entails its peel strength – ½ and 1 oz RT copper. It is crucial to conduct a repeated reflow or rework the entire process. The laminate has an ultra-low moisture absorption rate with a stable loss tangent. It helps in reducing the phase shift in diverse humidity and temperature environments. Further, less dimensional motion or movement adds to the stability phase over a broadband range of frequency.
RF-30A gets its optimization from the ceramic and thus has a low Z-axis coefficient of thermal expansion for an enhanced PTH (plated through-hole) reliability. It also helps ease the fabrication of multilayer electronic circuits. You can always rely on such properties for stable performance (PIMD).
PIMD is an acronym for passive intermodulation distortion in multi-frequency communication systems. PIMD properties get influenced by a variety of factors, including the following: power density distribution, circuit design, cables, connectors, PCB processing, soldering, and base materials. Other equally critical factors encompass worst PIMD performing parts, impedance discontinuities, etc.
However, most PTFE laminates with low-profile copper foils have the best performance. It is, however, crucial to remember that in other applications such as microstrip transmission lines, extra factors influence PIM levels. But RF-30A shows stable PIM performance besides proving less amenable to external influence. It also exceeds the PIM requirements in printed circuit boards with –153 dBc with a CL1/CL1 cladding developed or processed with modern parameters and processes.
Benefits of RF-30A
- It has an incredible PIM value in printed circuit boards, especially when measured below –160 dBc
- RF-30A PCB has an enhanced plated through-hole quality
- It has steady mechanical properties and proves stable at high temperatures and frequencies
- RF-30A also has a low moisture absorption rate and an excellent performance/price ratio.
- Lastly, it has an incredible peel strength.
- You can use the RF-30A in subcomponents and antennas
- You can also deploy it on RF passive component
- RF-30A can also apply in public address systems (PA)
Typical Values of RF-30A
|DK @ 1.9 GHz||IPC-650 220.127.116.11.1 (Modified)||2.97 ± 0.05||2.97 ± 0.05|
|Df @ 1.9 GHz||IPC-650 18.104.22.168.1 (Modified)||0.0013||0.0013|
|Df @ 10 GHz||IPC-650 22.214.171.124.1 (Modified)||0.0020||0.0020|
|PIMD||Internal (60 mil @1800 MHz)||dBc||-164||dBm||-121|
|Moisture Absorption||IPC-650 126.96.36.199||%||0.05||%||0.05|
|Peel Strength (1ounce. Copper)||IPC-650 2.4.8||lbs/in||12||N/mm||2.1|
|Volume Resistivity||IPC-650 188.8.131.52||Mohm/cm||3.0 x 109||Mohm/cm||3.0 x 109|
|Surface Resistivity||IPC-650 184.108.40.206||Mohm||2.0 x 108||Mohm||2.0 x 108|
|Flexural Strength (MD)||IPC-650 2.4.4||Psi||18000||N/mm2||126.5|
|Flexural Strength (CD)||IPC-650 2.4.4||Psi||1||N/mm2||119.5|
|Tensile Strength (MD)||PC-650 220.127.116.11||Psi||18000||N/mm2||133.6|
|Tensile Strength (CD)||PC-650 2.4.19||Psi||17000||N/mm2||105.5|
|Dimensional Stability (MD)||IPC-650 2.4.39 (after etch)||% (30 mil)||19000||% (60 mil)||0.025|
|Dimensional Stability (CD)||IPC-650 2.4.39 (after etch)||% (30 mil)||15000||% (60 mil)||0.026|
|Dimensional Stability (MD)||IPC-650 2.4.39 (after stress)||% (30 mil)||0.049||% (60 mil)||0.019|
|Dimensional Stability (CD)||IPC-650 2.4.39 (after stress)||% (30 mil)||0.031||% (60 mil)||0.011|
|Density (Specific Gravity)||IPC-650 2.3.50||g/cm3||2.16||g/cm3||2.16|
|Specific Heat||IPC-650 2.4.50||J/gK||0.95||J/gK||0.95|
|Thermal Conductivity||IPC-650 2.4.50||W/M*K||0.42||W/M*K||0.42|
|CTE (X-axis) (50°C – 150°C) I||IPC-650 2.4.41||ppm/°C||8||ppm/°C||8|
|CTE (Y-axis) (50°C – 150°C) I||IPC-650 2.4.41||ppm/°C||11||ppm/°C||11|
|CTE (Z-axis) (50°C – 150°C)||IPC-650 2.4.41||ppm/°C||60||ppm/°C||60|
Taconic RF-30A’s Processing Guidelines
If you want to design and have your FR-30A PCB fabricated, you must understand what it takes to process the material. It helps preserve its integrity and ensures optimum performance once it gets deployed. So, what processing guidelines should you consider when using a Taconic RF-30A laminate?
It is crucial to handle the RF-30A laminate with care. The laminate comes very similarly to a typical foil, and thus you must avoid scratching its surface. It is also prudent to avoid leaving your prints (fingerprints) by handling the laminate on the edges without gloves. Additionally, ensure an automatic load where no contamination or damage of the process equipment or unload equipment happens.
Using an RF-30A laminate unburdens you from having to bake the cores before precleaning. Further, baking can result in surface defects, which you will not want to happen. Additionally, micro-etching becomes obsolete as a requirement for roughening the surface. However, for precleaning purposes, RayMing PCB advises using an acid (5-10% sulfuric acid than a neutral to caustic rinse. It is also important to ensure it completely dries.
You must apply the resist material immediately after finishing the precleaning. Here, you can use the tacky roll cleaner, especially removing debris. You can also use dry film or liquid resist in optimizing pressure and temperature for dry films. However, it is vital to reduce the hold time between its application and its expose / imaging (resist).
You have to re-scale the Artwork, especially when processing thin cores or/and tight registration. For instance, cores with a CL copper will demonstrate less shrinkage than standard cores. What makes the RF-30A more interesting in this regard includes adjusting the Artwork lines in taking advantage of the superior etch factors. For imaging, you can perform the step wedge, as this will optimize the imaging energy. It also reduces the hold time between imaging/expose and development.
It allows you to perform breakpoints also adjust the speed according to what you want. For instance, you may need to reduce the Developer’s speed or raise the pH or temperature. The Insure Developer also possesses a regular or consistent cleaning schedule.
Like the Develop Resist phase, you can perform the breakpoint and adjust the desired speed. However, it may become necessary to slow the stripper or raise the concentration or temperature. Further, the Insure Stripper possesses a consistent cleaning routine.
Automatic Optical Inspection
It is always important for you to process the cores immediately after the resist strip to reduce oxidation. You may also have to incorporate an anti-tarnish to the resist strip. After that, you have to optimize the inspection parameters by ensuring the following.
- The CL becomes less reflective besides ensuring the thresholds get adjusted.
- Possibility of de-sensitizing ‘dishdown’ channel, especially for the laser-based systems
- That the part number designation ‘CL’ remains ‘CL’ to avert confusion on the settings
- You standardize a single foil manufacturer as the treatment may vary from one supplier to the next.
Begin with an alkaline cleaner before minimizing the micro-etch for this process. Optimize the Dwell Time in the oxide to get the anticipated cosmetics and weight gain. It becomes possible to reduce the time if you want to gain the same weight gain. For a minimum number of scratches, please ensure the right operator training.
Important Points to Note
CL copper offers an array of benefits in manufacturing besides desirable properties for multilayer printed circuit boards. Additionally, you can use the existing processes to consider the CL attributes and adjustments. For instance, micro-etching, oxidizing, and etching times can reduce. Stripping and Developing times can get increased. Hold times can get minimized to avert ‘lock-in,’ and finally, Artwork can require re-scaling besides the spaces/lines needing adjustment.
How does RF-30A Compare with TSM-DS3M and EZ-IO-F?
The most fundamental aspects you can always use to compare and distinguish between laminate products include their dielectric constant (DK) and tolerance, besides their loss factor. So how does RF-30A compare to TSM-DS3m and EZ-IO-F laminates?
|Loss factor||0.0020||0.0011||0.0015, 0.0014|
|Dk + Tolerance||2.97 ± 0.05||2.94 ± 0.05||2.80, 2.77 ± 0.05|
Picking apart can sometimes prove a complicated affair, especially as a beginner in designing and fabricating printed circuit boards. However, understanding the diverse parts, laminates, and their attributes come in handy in picking the correct one. But if you want to design a PCB for a subcomponent and antenna, RF passive components, or PA, then picking an RF-30A laminate or part can work a treat. However, consider all the attributes and values before making your material or part’s decision.