The massively-used copper clad laminate (CCL). can classified into different categories according to different classification standards including reinforcing material. used resin adhesive, flammability, CCL performance. The brief classification of CCL shown in the following table.
PCB base materials can be an important part of PCB. It determines the PCB table performance and range of software. Different products have different requirements on the PCB foundation material. Using the development of digital technology. PCB bottom material meet more difficulties. which also drive the introduction of copper clad laminate(CCL).
CCL has many classify methods. Generally, the reinforcing materials of the panel is split into five categories: paper foundation, cup fiber cloth bottom, composite foundation (CEM series), laminated multilayer plank bottom and special materials foundation (ceramic, metal primary bottom, etc.). If the CCL categorized by the adhesive resin, the normal used paper-based CCI, phenolic resin (XPc, XxxPC, FR-1, FR-2, etc.). epoxy resin (FE-3), polyester resin etc. Glass fiber fabric CCL has epoxy resin (FR-4, FR-5). which is the hottest type of cup fiber cloth. Furthermore, there are a few other special resins (such as cup fiber towel. polyamide fiber, nonwoven fabrics). bismaleimide altered triazine resin (BT), polyimide resin (PI) , Diphenylene ether resin (PPO). maleic anhydride imide-styrene resin (MS), polycyclic ester resin, polyolefin resin, and so on.
Intro of Materials and Guidelines of Circuit Board
In accordance to flammability characteristics. we can separate PCB into 94VO, V-1, V-2, 94HB
94HB: Normal cardboard (non- fireproof. the cheapest grade material, can't made as power plate)
94V0: flame retardant cardboard,
22F: single-sided fiber cup board
CEM-1: single-sided fiber cup board
CEM-3: double-sided half-glass table. (You should use this materials rather than FR-4 to conserve $1~$2/ sq . meter
FR-4: double-sided fiber cup board
Halogen-free base materials identifies the material. that will not contain halogen (fluorine, chlorine, bromine). The materials which contains Halogen will produce poisonous gas when burning.
Tg is the vitrification temperature, you can address it as melting point.
The circuit panel must be resistant to burning up. The board can't be burnt but it'll be smooth when warmed. At this warmed temperature point named vitrification temperature.
The vitrification temperature (Tg point) relates to the sturdiness of PCB. what exactly is the benefit of high-Tg PCB circuit planks?
High-Tg PCB will be. from the cup condition into rubber condition . When the temperature increases to a certain level. so the Tg quantity described maximum temperature (℃) that PCB can be rigid. Normal PCB foundation material at temperature can be softening, deforming, Melting. also get much worse performance in the mechanical, electric characteristics.
Normal PCB materials Tg point is 130 ℃. Tg point for high Tg PCB is higher than 170 ℃. For medium Tg PCB, Tg point is about 150 ° C.
With high Tg point, high-Tg PCB has better warmth resistance. moisture level of resistance. chemical resistance, balance and other characteristics. TG
In the lead-free digesting. the high-Tg PCB get wider program because lead-free digesting. need higher temperature than digesting with lead.
Using the quick development of the consumer electronics industry. especially in the computer as the representative of the digital products. electric engineers want PCB with small vias. fine lines, lower thickness, it also need High-Tg materials.
High Tg PCB is much better than normal FR-4 bottom materials. yet the price will be higher.
Aluminium board is some sort of metallic foundation copper clad plank. with good temperature dissipation ability. As well as the solitary layer panel comprises three layers. circuit coating (copper foil), insulating level and the steel bottom. The double-sided table utilized in high-end design contain circuit coating. insulation layer, aluminium based, insulating level, circuit coating. Multilayer Light weight aluminum board is hardly ever seen. we recommend you to use one layer Aluminium board. 2 or even more layers Light weight aluminum board is very costly.
FR is stand for FIRE RETARDENT. For all type of PCB manufacturing, most common glass laminated material is FR4. Based on woven glass-epoxy compounds. FR4 is a composite material which is most useful . because it provides very good mechanical strength.
-FR-1 and FR-2
This material made from paper and phenol compounds. and this material used for only single layer PCB. Both FR1 and FR2 has similar characteristic. the only difference is glass transition temperature. FR1 has higher glass transition temperature compared to FR2. These materials is also sub divided in standard, halogen free and non-hydrophobic.
These material made from paper and two layer of woven glass epoxy. and phenol compounds and this material used for Single sided PCB only. CEM-1 can used instead of FR4, but price of CEM1 is higher than FR4.
this material is white coloured, glass epoxy compound which used in double layer PCB. CEM-3 has lower mechanical strength compared to FR4, but it is cheaper than FR4. So, this is a good alternative of FR4.
This material used in flexible PCB. This material made from kepton, rogers, dupont. This material has good electrical properties, felicity. wide temperature range and high chemical resistance. Working temperature of this material is -200 ͦC to 300 ͦC.
Prepreg means pre-impregnated. It is a Fiberglass impregnated with resin. These resins are pre- dried, so that when it heated, it flows, sticks and completely immersed. Prepreg has adhesive layer which gives strength like FR4. There are many versions of this material according to resin content. SR- standard resin. MR- medium resin and HR- high resin. This chosen according to required thickness, layer structure and impedance. This material also available in high glass transition temperature and halogen free.
PCB material selection
For buildings, there is a well-defined order of construction. beginning with a concrete foundation. followed by the steel or wood framing, floors and roofing. Likewise, board fabrication consists of the substrate, laminate, solder mask and silkscreen. The silkscreen used for identification markings that are invaluable for PCB assembly. Solder mask is a protective layer that guards against external contaminants. and provides the required isolation between surface elements like pads. copper traces and drill holes. The structural integrity. or foundation of your board defined by the substrate and laminate. Selecting the best circuit board material for these foundational elements. which can chosen based on your board type. determines your board’s manufacturability, functionality. and life cycle.
The circuit board foundation, sometimes referred to as the base. comprises the substrate (or core) and the laminate. The substrate is the non-conductive dielectric material. chosen based upon the dielectric constant, dk. Laminates when used in conjunction with substrates. provide the copper foil or surface material. But, laminates may themselves used as core material in some board constructions.
Substrates are dielectric composite structures. that comprised of epoxy resin and paper or glass weave (sometimes unwoven). which may supplemented by ceramics to increase the dielectric constant. Substrates made to meet certain property requirements. like the glass transition temperature (Tg). which is the point where heat causes the material to deform or soften. and may customized. But, there are a wide variety of standard substrates from. which the majority of PCBs fabricated. These include FR-1 thru FR-6, CEM-1 thru CEM-5, G-10 and G-11, Aluminum or insulated metal substrate (IMS). Polytetrafluoroethylene (PTFE), RF-35, Polyimide, Alumina and flexible substrates Pyralux and Kapton. FR-4 is by far the most implemented of these substrates.
Laminates manufactured under pressure and consist of cloth. or paper layers and thermoset resin. as with substrates, laminates can made to meet custom requirements or properties. Properties of interest for laminates include tensile. and shear strength, the coefficient of thermal expansion, CTE, and Tg. Dielectrics used for laminates include FR-1, FR-4, polytetrafluoroethylene (Teflon), CEM-1 and CEM-3. Also common are pre-preg materials FR-2 thru FR-6, CEM-1 thru CEM-5 and G-10.
Together the substrate and laminate define the basic electrical. mechanical and thermal circuit board properties that. when used in conjunction with an accurate board type. enable you to make the best selection of PCB material for your design.
component location – single-sided, double-sided, embedded
stackup – single layer, multilayer
design – module-based, custom, special
bendability – rigid, flex, rigid-flex
strength – strong, strong
electrical functionality – high frequency, high power, high density, microwave
The first three criteria above are poor candidates on. which to base your selection as they are not based on circuit board material properties. While bendability and strength are good physical criteria. they do not provide guidance on your board’s ability to function as desired. Electrical functionality based on PCB function. which makes it a good criterion for design-based circuit board material selection. According to function, PCBs may classified as the following board types:
High Frequency (High Speed) . These boards can accommodate frequencies in the 500MHz – 2GHz range.
High Power (High Current) . These boards must be able to carry high currents, which usually requires wider traces. and thicker copper. withstand and dissipate high temperatures.
High Density (High Density Interconnect). complex, these boards have thin traces, use laser microvias and thin high-performance materials.
Microwave – Microwave boards usually refer to PCBs. where signal speeds from 1GHz to hundreds of GHz are present. but, the microwave spectrum actually extends from 300MHz to 300GHz.
The board types above can used to select the circuit board material best suited for your design.