It is widely known that BeO with high thermal conductivity (200-250W/m.k). High dielectric constant 6-7 (0.1MHz) and dielectric loss tangent is 10-4 (0.1GHz), extremely high working temprature. It is ideal material for ceramic PCB, lots of engineers want to use it as DBC ceramic PCB substrate.
But it is not popular in ceramic PCB market, comparing with Al2O3, AIN, Si3N4, or ZrO2, as the powder of BeO is extremely poisonous.
The poison gas is produced by the reaction between oxygen, Cu and BeO under 1065-1085 degrees Celsius, so it is limited to make cooper on BeO substrate, it has caused ALN (Aluminium脗聽Nitride) is becoming more and more popular.
Right now, only few countries are using BeO to make ceramic PCB, such as USA, Russia and China. USA had biggest capability to make BeO , and here in China, there’re still some companies to make BeO raw material and among them, a few companies to produce direct copper bonded (DCB) on BeO because of environment limitation.
Though BeO is not popular for DBC technology, but it is feasible for thick film technology, because when the mentalization of Ceramic PCB, the conductor (Au or AgPd) on BeO substrate was made by silk-screen printing, and drying temperature is only around 850C, no need to under high temperature environment, so there is no chemical脗聽reactions, no environment issue.
Below the thick film ceramic PCB manufacturing process for your reference.
EBest Circuit (Best Technology) is a full turn-key assembly service company, we can supply the assembled board with very nice and clean surface.
Do you want to know how we control the cleaning process of PCBA? We would like to share the full cleaning process.
As we know, flux is used when soldering electrical components to a printed circuit board.
After assembly process finished, we need to remove all the unnecessary flux paste or other solder flux/ residue in order to avoid any quality issue.
Although it is a simple work, but to prepare some tools and preparation is necessary and important. Like wash board water, dust-free cloth, brush,Tweezers, static bracelets, finger gloves
Here is the how the cleaning process we made:
Step1:
Use brush to brush the solder joint and solder flux on the soldered PCB. Applying some alcohol or acetone onto the brush, do not use too much pressure, as this may cause the solder point to break. Repeat the procedure as necessary, to remove remaining flux residue on the PCBA.
Step1: Brush the solder joint and solder flux on the soldered PCB
Step2:
Wipe with a clean dust-free cloth to clean the assembled PCB.
Keep board clean and tidy to make sure no impurities and finger marks. Do the same process for bottom side.
Step2:Wipe with a clean dust-free cloth to clean the assembled PCB.
Step3:
When above step finished, keep the board for an extra day to let the board dry enough before packing. Best QC guys will do final inspection for the finger prints under light. this will be helpful to check the cleaning result further.
Step3: final inspection for the finger prints under light
Step4:
Finally, use dust-free cloth to do the final cleaning and let the board dry and clean enough before package.
Step4: use dust-free cloth to do the final cleaning.
Above are the process for how we clean the assembled boards.
Best Tech is a very professional manufacturer in printed circuit board and assembly. We clean each of assembled boards as the procedure we showed above.
If you are interesting to know more process for how we control the quality for the PCB assembled boards, contact us at any time, we will show you more.
As we know, the extra thin PCB means the thickness of printed circuit board is more thin than normal PCB, which is refer to a thickness smaller than 0.4mm for 1L/ 2L & 4L PCB. For extra thin PCB, we know they are all very thin and are easily to be broken, so the option for the surface treatment of the extra thin PCB is very crucial.
0.15mm extra thin FR4 PCB_EBest Circuit (Best Technology)
Generally, there are 3 kinds finishing can be recommended for the extra thin PCB. It is OSP, ENIG (Electroless Nickel Immersion Gold), and ENEPIG.
extra thin pcb finishing
But you may want to ask that lead-free Tin is also a common finishing for the PCB. Why not recommend LF HASL?
That芒鈧劉s because while LF HASL Process, the PCB will be easy to be blew away, people will use heated compressed air to leveling (blowing) on the coating molten tin (lead) solder, during this process, the traces will be easy to be broken as well.
So normally, we will not recommend the LF HASL finishing for an ultra thin FR4 PCB.
HASL lead-free is only suitable for a board with minimum thickness of 0.6mm, while the standard gold immersion surface coating can support PCB with a minimum thickness of 0.2mm. For the surface treatment of ENEPIG , which plate only needs to be about 0.1 microns for palladium and about 0.1 microns for gold, (palladium is a precious metal that is much harder than gold), so for board with ENEPIG finishing, its surface will looks more smooth, that芒鈧劉s also why it is the most recommended surface treatment for an extra thin PCB.
0.13mm extra thin Rigid FR4 PCB_EBest Circuit (Best Technology)
If you are searching for an extra thin PCB, feel freely to ask or send your inquiry to us. We will be pleased to share you more information regarding the extra thin PCB.
SinkPad PCB, also called Heat Sink or DTP (direct thermal path)脗聽PCB, it is a type of Copper base PCB used in thermoelectric脗聽separation application. It generally used for high power LED, the pad of LED touch the copper base directly, so that the heat generated by LED will dissipate quickly, which can achieve the best heat dissipation and conduction.
SinkPad PCB
Thermoelectric separation technology is based on the higher heat dissipation requirements of high power electronic products, which needs to meet two basic conditions:
1.LED pad touches the base substrate directly.
It means we need to increase the path of the LED pad to the base substrate to accelerate the heat emission from the base material.
Two layers SinkPad PCB Stack up
2.Higher heat dissipation substrate materials
Copper has a thermal conductivity of 401W/m脗路K, while aluminum has a thermal conductivity of 237W/m脗路K. Obviously, copper has better thermal conductivity because of its high density, high mass. Therefore, a SinkPad PCB usually means a SinkPad copper base PCB.
If we observe carefully, we will find that most of the high-quality surface light lamps in the market脗聽use COB light source, such as LED spotlights, Automotive, LED Backlight for LED TV, etc.脗聽What are the advantages of such choice?
Automotive
LED Backlight for LED TV
LED spotlights
First of all, we need to脗聽how the COB differ from the脗聽common MCPCB. “Chip-On-Board” Metal Core PCB脗聽is a type of MCPCB used in thermoelectric separation application. By using COB, the micro-chip (also known as “die”) directly touch the metal core where the heat dissipate, and electrically interconnect the trace of circuit board (wire-bonding) so that power supply can be provided.
High thermal conductivity(137W/m.K), High insulation, High pressure resistance
High reflectivity: mirror aluminum芒鈥奥98% (The reflectivity of Taiyo Soldermask used in common MCPCB is 75-80%, the highest is only 90%)
BAS15191
BAS15192
Since脗聽the脗聽COB is packaged directly on the MCPCB, it芒鈧劉s脗聽easy assembly for high powers LED, direct heat dissipation through the substrate can not only reduce the manufacturing process and cost of the bracket, but also have the advantage of reducing heat dissipation resistance. So the spotlight produced by COB technology will be lighter, more flexible and able to realize more possibilities on the stage.
If you are also interested in COB, please feel free to contact me, I芒鈧劉m looking forward to communicating more with you.
In recent years, there are more and more customers request to manufacture PCB with high Tg, in the following we would like to describe what is high Tg PCB.
fr4 170tg
Normally high Tg refers to high heat resistance in PCB raw material, the standard Tg for copper clad laminate is between 130 芒鈧 140芒鈥炂, High Tg is generally greater than 170芒鈥炂, and middle Tg is generally greater than 150芒鈥炂. Basically the printed circuit board with Tg芒鈥奥170芒鈥炂, we call high Tg PCB. As the rapid development of electric industry, especially for the computer as the representative of electronic products, developing toward the high performance, high multilayer requires PCB substrate material with higher heat resistance to ensure high reliability. On the other hand, as a result of development of SMT, CMT with high density pcb assembly technology, the PCB manufacturing with small hole size, fine lines and thin thickness are more and more inseparable from the support of high heat resistance.
fr4 170tg
If the Tg of PCB substrate is increased, the heat resistance, moisture resistance, chemical resistance and stability of printed circuit boards will be improved as well. The high Tg applicates more in the lead free pcb manufacturing process.
Therefore, the difference between general FR4 and high Tg FR4 is, in the hot state, especially in the heat absorption with moisture, the high Tg PCB substrate will perform better than general FR4 in the aspects of mechanical strength, dimensional stability, adhesiveness, water absorption and thermal decomposition.
EBest Circuit (Best Technology), a China- based assembly manufacturer will be exhibiting at electronica Munich2020 in Bavaria, Germany at booth No. 623(Hall B1) from November 10, 2020 to November 13, 2020(Western Time). Actually, we have participated in this exhibition for continuous 2 years. Here are some pictures for your reference.
pcb exhibition
pcb exhibition
pcb exhibition
pcb exhibition
At our exhibition booth, attendees will be able to learn more about our company for PCB manufacturing脗聽and PCB assembly脗聽technology.
For interested professionals, EBest Circuit (Best Technology) had on hand experts to offer detailed insights and experience on PCB assembly, covering PCB prototype and low/high-volume production. For more information on PCB assembly and fabrication, welcome to visit our booth.
You are warmly welcome to see how we can manage the components wastage and efficiency to help save your time, money and energy.
About electronica Munich:
Electronica is the international trade show for electronic components, systems and applications and shows the full range in all its diversity in width and depth as the world’s leading trade fair. It reflects the high degree of innovation throughout the industry. Exhibitors and users in the areas of systems, applications and technologies of electronics can receive the information of the latest innovations and developments in the fields of system peripherals, power engineering to printed circuit boards or EMS.
Welcome to visit脗聽us at Booth 623 from November 10, 2020 to November 13, 2020(Western Time).
The abbreviations PWB and PCB are very common, especially in the field of electronics manufacturing. Therefore it is necessary to gain a clear understanding of the meaning of each one and the differences between the two. On this article, we will help our readers to distinguish PWB from PCB.
pcb vs pwb
PCB: Based on insulating substrate, it means a kind of products on which the wires are connected and components are printed from point to point on a dielectric substrate in a predetermined design. It is the English abbreviation of Printed Circuit Board.In a word, PCB stands for聽printed circuit board, where the width, side to side and multi-layer relationship(spacing) of conductor runs has or is designed to have a specific effect on circuit operation other than just a point to point connection.
PWB: Based on insulating substrate, it means a kind of products on which the wires are connected from point to point on a dielectric substrate in a predetermined design. However, there is no printed component on it. PWBs are the early name of the British, because at that time there were only circuit diagrams on the circuit board, but no printed components. So they belonged to the more primitive board. Under its effect, now many traditional British and some Hong Kong people still call the circuit board to be PWB, which is the English abbreviation of Printed Wire Board. In a word, PWB stands for聽printed wiring board, one of the first uses when the issue was only a point to point connection.
The PCBs are the boards already equipped with various components, however the PWB is just a designed substrate with no components.
pcb vs pwb
Moreover, PWB vs PCB greatly varies from one region to the other. For example, in the United States of America, the term Printed Circuit Board is more common in use while the use of the name PWB is more commonly used in Japan. In Japan, PWB is more preferred that PCB because it prevents confusion with another name, polychlorinated biphenyls, which refers to a particular poison available in Japan.
For your more information, in approximately 1999 the IPC Technical Activities Executive Committee made a mandate to only use the term PCB for all new document development because more often than not the printed circuitry design will have an impact on function.
If you are still confused or have any queries or comments about PCB, do not hesitate to contact us. Our sales team can give you a reply at our soonest convenience.
PCB is an indispensable part for any electronic equipment in small toys or computers., etc. The complex interconnection components include resistor, diode and capacitor, which help components work normally in series. In a sense, it is similar to the 芒鈧揵rain芒鈧澝偮爋f the system. PCB assembly process must be of no any mistakes. Here are some points that need to be paid attention:
1.Supply chain management: In order to create high quality PCB, the first thing needing consideration is supply chain. For the availability, both quality and price are important, so is delivery time of components.
pcbassembly
2.PCB layout. The common question during manufacturing stage is pcb layout in minor differences. Even though various types of designs looks the same to outward seeming, the manufacturing processes are different. You need to ensure PCB layout is feasible during manufacturing process.
3.Test-test has to be conducted after PCB assembly. What needs to be done is to design test point. Some tests include:
Micro-section analysis-also referred to as cross section analysis. This test contributes to identifying components fault and thermal-mechanical faults.
pcbassembly
Solderability test. This test contributes to testing reliability of PCB solder pad, to ensure a firm surface and a reliable soldering point. It also contributes to confirming if storage will have an effect on solder components.
PCB pollution test-This can test many issues, such as corrosion and degradation. Scaling powder residue will result in pollution and thereby case components failure. Pollution analysis is famous for its accuracy and preciseness.
Optical microscope-This can test the issues relevant to PCB and soldering as well as overall pcb assembly. The process is famous for its speed, as it involves using high-power microscope to inspect incorrect structure.
If you’ve ever made a pie with your kids, you know that the thickness of your crust is important. Too thin, and the pie falls apart into a mess of filling. Too thick, and you might as well be chewing on a loaf of bread. Getting the thickness just right is what makes a pie worth eating.
Even though PCB substrate materials are non-conductive and do not carry current, the board material still affects the electrical performance. FR4 PCB substrate is widely used, and a thorough understanding of this material is very necessary.
FR4 PCB
FR4 Thickness Design Considerations
If you start your design process by choosing the correct board thickness, you will avoid to redesign later. A number of factors are influenced by the board thickness. Before you start designing your board, think about the following design issues:
Form factor and flexibility: Does your PCB have a strict form factor requirement? Thinner boards tend to be used in smaller devices and can flex more than a thicker board. A more flexible board may be unusable with a pick & place machine. Electrical connections in flexible boards can also break unless they have some mechanical support.
Components and connections: Will the device have any components that require the Printed Circuit Board to have a specific thickness? Components like USB edge connectors and some through-hole components require PCB in correct thickness. BGA connectors generally require thicker boards.
FR4 PCB
Impedance matching: Traces on adjacent layers in multi-layer boards form a capacitor, and the layer thickness and its dielectric constant determines the equivalent capacitance. Impedance matching is critical, and the capacitance must be taken into consideration when designing the board. This is especially true in HDI PCB.
High-speed devices: If you are working with a high-speed device, FR4 is always not the best option, and some other material should be used instead. FR4 PCB could be used in high-speed devices when the layers are coated with high-speed laminates. These laminates offer significantly improved electrical performance over standard FR4, and generally a combination of FR4 and a high-speed laminate may be preferable to an alternative material.
RF losses: FR4 tends to have higher losses than other PCB materials that are specialized for RF applications. Traces on FR4 will have larger attenuation at RF frequencies than other specialized materials for a given board thickness. The board thickness also changes the effective dielectric constant of the board, which then changes the required impedance matching in RF circuits.
Thermal and Reliability Considerations
All materials expand at higher temperatures, and the thermal expansion coefficient must be taken into consideration when choosing the board thickness. The thermal expansion coefficient of FR4 changes drastically above the material芒鈧劉s glass transition temperature (140芒鈥炂). The board can become electrically and mechanically unstable when the board operates above the glass transition temperature.
The reliability of the trace materials, laminate materials, and solder joints on a PCB laminate are determined by the resistance to thermal cycling. When the thermal expansion coefficients of the different materials are mismatched, fatigue occurs after repeated thermal cycling. Copper plating in vias and solder balls are especially vulnerable to damage under thermal cycling.
This is a greater problem in thick FR4 PCB with high aspect ratio vias. Plating damage in through-hole vias, lifted pads, and cracked surface resin can occur under the stress caused by thermal cycling. A thicker board will have a larger expansion magnitude for a given via aspect ratio, resulting in more damage to the board and the electronic components. Thermal stresses can be huge when an FR4 PCB runs above the glass transition temperature.
Volumetric expansion is also critical in rigid-flex FR4 PCB. Thermoplastic adhesives with low glass transition temperatures and high Z-direction expansion coefficients can exhibit very large volume expansion at high temperature. Z-direction expansion in these situations can be as large as 500 ppm/茠.
Even though聽a thicker FR4 PCB聽has greater thermal mass and can dissipate more heat from electronic components, there is also the potential for more damage due to thermal expansion. Therefore, how to choose聽between a thick and thin FR4 PCB that satisfies all other requirements, the thinner board may be a better choice if the FR4 PCB聽will undergo thermal cycling frequently.
If you have any comments. queries or suggestions on this, welcome to contact us.
