Materials for Printed Circuit Boards

The basic structural elements of a printed circuit board include a dielectric substrate (hard or flexible), on the surface of which copper conductors (traces) are located. Additional elements such as soldering points (pads), vias, plated and non-plated holes (mounting), large copper areas (polygons) for heat dissipation, shielding, etc., are used for installing electronic components and their connections.

Dielectric substrates can be made of glass-epoxy laminates or composite materials.

Multilayer printed circuits contain the following elements: basic dielectric material (core), reinforcing material (prepreg, used as dielectric layers during the assembly of a multilayer board), and copper foil (RCC, i.e., copper foil with an adhesive layer).

When choosing a dielectric, parameters such as glass transition temperature (T_g), dielectric constant (D_k), and dielectric loss factor (D_f) are most commonly taken into account. The last two parameters are particularly important for printed circuits intended for very high frequencies and microwave ranges.

The glass transition temperature is the temperature at which the material transitions from a solid to a plastic state. Usually, the glass transition temperature represents a temperature range (for example, 135 - 170 °C for FR4). The higher the glass transition temperature of the epoxy resin in a glass-epoxy laminate, the lower the coefficient of linear expansion of the dielectric, which can lead to defects in printed circuits.

Another important characteristic of the material is the dielectric constant (relative permittivity) - the ratio of the capacitance of a test capacitor in which the material is used as a dielectric to the capacitance of the same air capacitor. This characteristic should be taken into account (especially for printed circuits designed for high-frequency ranges) because the high performance of modern electronic circuits places special requirements on parameters such as signal delay time and capacitance of signal lines. The transmission speed of signals in the conductors on the printed circuit board mainly depends on the dielectric constant. The values of the dielectric constant for modern materials used in the production of printed circuits range from 2.2 to 10.2.

The dielectric loss factor in the insulating material is defined as the ratio of the total power loss in this material to the product of voltage and current in the capacitor in which this material is used as a dielectric. The loss factor changes with frequency, resin content in the laminate, temperature, and humidity. The smaller the loss factor, the better the material. In this case, the dielectric loss factor is related to the total signal power loss in the signal lines. It usually increases with frequency. The higher the frequency and, consequently, the dielectric loss factor, the more distorted the signal will be.

For printed circuits on a metal core, the main parameters are thermal conductivity (the material's ability to conduct thermal energy from hotter areas to cooler areas) and breakdown voltage (the voltage at which the specific electrical resistance of the material sharply decreases). It should be remembered that the operating voltage of the system should be lower than the breakdown voltage by 2.5 - 4 times.

Below, you can read descriptions and typical parameters of the basic materials used in our factories, and download technical documentation for each of them.

Types and parameters of materials used for Printed Circuit Board production*

*This list of materials is basic, so if you do not find the required material, we can purchase it upon request or assist in selecting the closest equivalent.

Materials for standard Printed Circuit Boards

Material	Description	Glass transition temperature Tg	Dielectric constant Dk	Manufacturers and Brands
FR-4 or FR4	FR-4 stands for Fire Retardant class 4. This laminate is made from glass fiber with epoxy resin. It is the most commonly used material for printed circuit boards.	125-140°C	4,4-4,8	GoldenMax GF21 KingBoard KB6160 Nouya NY1135 Nouya NY1140 Nouya NY2140 Shengyi S1141
FR-4 Mid Tg	Glass fiber laminate with a slightly increased Tg parameter for the production of double-sided and low-layer count multilayer printed circuit boards. It is an enhanced version of the standard FR4 material.	150-155°C	4,6-4,8	Nanya NP-155F Nouya NY2150 Shengyi S1000 Shengyi S1000H
FR-4 High Tg (>170°C), FR-5	Glass fiber laminate based on blends of modified epoxy resins. It has increased thermal resistance and greater parameter stability at high temperatures. Recommended for use in multilayer printed circuits and circuits with high conductor density (HDI).	170-185°C	4,1-4,8	ITEQ IT180 KingBoard KB6167F Nanya NP-175FM Nouya NY1170 Nouya NY2170 Shengyi S1000-2
FR-4 High CTI (>600V)	Material based on modified epoxy resins. It is used for printed circuits with high levels of operating voltage in high humidity conditions.	125-135°C	4,5-5,0	GoldenMax GF11-T6 Nouya NY1600 Shengyi S1600 Kingboard KB6165 ITEQ IT158A ITEQ IT180A Isola DE104KF
FR-4 Halogen Free	This type of laminate does not contain halogen, antimony, phosphorus, etc., and does not emit harmful substances during combustion.	140-150°C	4,22-4,7	KingBoard KB6165G Shengyi S1155
CEM-1	CEM-1 (Composite Epoxy Material) is a type of laminate made from a combination of glass fiber cloth, epoxy resin, and paper layers. CEM-1 laminates are typically used in products where PCBs are not exposed to harsh environments, for example, in consumer electronics.	90°C	4,2	KingBoard KB5150
CEM-3	CEM-3 is a more advanced and durable PCB material compared to CEM-1, capable of withstanding slightly higher temperatures and more challenging conditions.	125°C	4,4-4,8	KingBoard KB7150
Rigid PI (polyimide)	Polyimide laminate for the production of rigid printed circuit boards. It consists of a polyimide substrate and several layers of prepregs (PP).	>250°C	4,2-4,4	Arlon 33N Arlon 85N Shengyi SH260

Materials for Flexible and Rigid-Flex Printed Circuit Boards (Flex/Rigid-Flex PCB)

Material	Description	Glass transition temperature Tg	Dielectric constant Dk	Manufacturers and Brands
Pl (polyimide)	Thin films made from polymerized polyimide. This material is used for the production of flexible and rigid-flex printed circuit boards.	280-350°C	3,2-3,6	Panasonic RF770 Panasonic RF775 Shengyi SF302 Shengyi SF305
PET (polyethylene terephthalate)	Films made from a thermoplastic polymer belonging to the class of polyethers. This material has high mechanical strength and is resistant to repeated deformations.	100°C	3,3	Jiu Jiang LPET

Materials for Very High Frequencies and Microwave Ranges

Material	Description	Dielectric loss factor Df	Dielectric constant Dk	Manufacturers and Brands
PTFE	Polytetrafluoroethylene (PTFE) polymer reinforced with glass fiber. This material is known for its high reliability, electrical strength, resistance to moisture, and ability to operate at high temperatures.	0,0004-0,0078	2,17-10,2	Arlon DiClad series Rogers RT\duroid 5870 Rogers RT\duroid 5880 Taconic TLY Series
PTFE with ceramic filler	Polycarbonate-based polymer (carbon resins) with a fine ceramic filler, reinforced with glass fiber.	0,0011-0,0040	2,94-10,2	Arlon 25N/25FR Rogers RO3000 series Rogers RO4000 series Rogers RO4400 prepreg Taconic RF-10 Taconic RF-35 Taconic RF-60A Taconic TSM-DS3M
Ceramic composites	Composite materials based on ceramics with organic binders are characterized by low losses.	0,0016-0,0023	3,0-12,85	Rogers TMM series Taconic HF-300
FR4 High Frequency	This refers to a group of modified glass fiber laminates designed to operate in high-frequency ranges.	0,003-0,010	3,5-3,6	Shengyi S7136H Tuc TU-872 SLK

Materials for Printed Circuits on metal substrates

Material	Description	Thermal conductivity λ (W/m*K)	Breakdown Voltage kV	Manufacturers and Brands
Aluminium CCL	This is a type of copper laminate known as Aluminium Clad Copper Laminate, which consists of an aluminum substrate and a thin dielectric layer with a copper layer on top. This construction allows for better heat dissipation, which is particularly important in high-power applications.	0,6-3,0	3-5	Boyu AL-01-P Boyu AL-01-A Boyu AL-01-B Boyu AL-01-L GoldenMax GL12

Other materials for Printed Circuit Boards

Materiał	Opis	Glass transition temperature Tg	Dielectric constant Dk	Manufacturers and Brands
PP (prepregs)	Prepreg is a composite material consisting of reinforcing fibers such as glass or other types, which have been impregnated with partially cured resin. The resin is typically epoxy, but it can also be polyimide or another type of polymer.	130-180°C	2,8-4,6
RCC	The acronym stands for Resin Coated Copper, which refers to a copper foil with a layer of resin. It is used as the base material for the layers of multilayer printed circuits, including circuits in HDI technology.	150-170°C	3,5-4,4
Copper foil	This is a material in the form of thin copper foils, typically available in rolls. Copper foils are used to create stacks of layers in printed circuits by pressing them together with prepreg layers and other laminates.	-	-

Detailed parameters and datasheets of materials for standard Printed Circuit Boards.

FR-4

The abbreviation FR-4 stands for Flame Retardant 4. The term "FR" originates from the rating system developed by NEMA (National Electrical Manufacturers Association, USA). This specific rating indicates that the material meets the UL94V-0 standards, meaning it is flame retardant. It is one of the most commonly used materials for printed circuit boards. The material finds a wide range of applications, from consumer electronics to medical, military, and aerospace devices, although it is not recommended for high-frequency applications.

Furthermore, FR-4 is known for its good mechanical properties, such as high strength, and it is easy to work with, allowing processes like milling or cutting. It also possesses good chemical resistance, low water absorption, and is heat-resistant. However, one of its main limitations is its poor thermal conductivity, which can be a challenge in high-power applications.

In general, FR-4 is a versatile and cost-effective material for printed circuit boards. However, its limitations should be taken into consideration when choosing it for a specific application. Engineers may consider using other materials like polyimide or ceramic substrates for high-power or high-frequency applications.

Depending on its properties and application, FR-4 is divided into the following subclasses:

• Standard, with a glass transition temperature (Tg) of ~ 130°C, with or without ultraviolet (UV) blocking. This is the most common and widely used type, also the least expensive within the FR-4 category.

• Medium Tg, with a glass transition temperature (Tg) of ~ 150°C. Suitable for lead-free soldering technology and for most low-layer count multilayer printed circuits.

• High Tg, with a glass transition temperature (Tg) of ~ 170°C-185°C. Suitable for lead-free soldering technology and recommended for use in multilayer printed circuits with a higher layer count (above 6 layers).

• High Comparative Tracking Index (CTI) ≥ 400, ≥ 600.

• Halogen-free, suitable for lead-free soldering technology.

High Tg FR-4 laminates are manufactured using dianic epoxy resins and a special type of woven glass fiber. They are essential for applications where printed circuits will be operated in challenging thermal conditions, such as the automotive industry, industrial electronics, or aerospace industry.

High CTI (Comparative Tracking Index) laminates are used in applications where printed circuits will be operated in harsh environmental conditions, such as high humidity, large temperature variations, or demanding industrial conditions. These laminates have higher breakdown resistance, providing better protection in critical applications. The CTI parameter represents the relative resistance of the material to the formation of a conductive path on the surface of the printed circuit when the surface is exposed to electric fields in the presence of contaminants containing water. It indicates the highest working voltage for a given laminate. The higher the CTI value, the higher the breakdown resistance.

FR-4 laminate achieves its flame resistance through the presence of bromine, which is a halogen commonly used in industry due to its flame-retarding properties. However, bromine is a highly toxic chemical component that is released into the environment during material combustion. To limit the use of such substances, halogen-free laminates are used. These materials are produced based on modified epoxy resins that do not contain halogens, antimony, and phosphorus.

FR-4 laminates used in our production and their typical parameters
(you can download datasheets for these materials via the link):

Manufacturer/Brand	Glass transient temperature Tg	Dielectric constant Dk	Datasheet
Laminates with standard glass transition temperature
GoldenMax GF21	>125°C	4,4-4,8	Download
KingBoard KB6160	135°C	4,58	Download
Nouya NY1135	135°C	4,6	Download
Nouya NY1140	140°C	4,6	Download
Nouya NY2140	>135°C	4,8	Download
Shengyi S1141	140°C	4,4	Download
Laminates with medium glass transition temperature
Nanya NP-155F	155°C	4,6-4,8	Download
Nouya NY2150	>150°C	4,7	Download
Shengyi S1000	155°C	4,7	Download
Shengyi S1000H	160°C	4,9	Download
Shengyi S1141 150	150°C	4,6	Download
Laminates with high glass transition temperature
ITEQ IT-180	175°C	4,4	Download
KingBoard KB6167F	>170°C	4,8	Download
Nanya NP-175FM	170°C	4,1-4,3	Download
Nouya NY1170	170°C	4,6	Download
Nouya NY2170	170°C	4,6	Download
Shengyi S1000-2	170°C	4,8	Download
Shengyi S1000-2M	185°C	4,6	Download
Laminates with high CTI
GoldenMax GF11-T6	>125°C	4,5-4,8	Download
Nouya NY1600	135°C	4,6	Download
Shengyi S1600	135°C	4,7	Download
Shengyi S1600L	135°C	5,0	Download
Halogen-free laminates
KingBoard KB6165G	150°C	4,7	Download
Shengyi S1155	140°C	4,22	Download
Polyimide laminates
Arlon 33N	>250°C	4,25	Download
Arlon 85N	>250°C	4,39	Download
Shengyi SH260	>250°C	4,22	Download

FR-1/FR-2

FR-1 and FR-2 are material classes according to the NEMA classification. These composite materials are produced from phenolic-paper base and are used exclusively for the production of single-sided printed circuit boards. FR-1 and FR-2 have similar parameters, with FR-1 differing only in a higher glass transition temperature. Due to the similarity in parameters and application range, most material manufacturers produce only one of these materials, most commonly FR-1. These materials are well-suited for mechanical processing (milling, cutting). They have a UL94-V0 flammability rating.

They are divided into the following subclasses:

• Standard

• Halogen-free, without phosphorus and antimony, non-toxic

• With normalized CTI index ≥ 400, ≥ 600

• Waterproof;

CEM-1

CEM-1 is a material class according to the NEMA classification. These composite materials are produced from a phenolic-paper base, with two layers of glass fabric on the outside. They are typically milky-white or milky-yellow in color. They are not compatible with the through-hole metallization process, which is why they are used only for the production of single-sided printed circuit boards. Their dielectric properties are similar to FR-4, but their mechanical properties are slightly inferior. CEM-1 is a good alternative to FR-4 for the production of single-sided printed circuit boards when cost is a determining factor. These materials are well-suited for mechanical processing (milling, cutting). They have a UL94-V0 flammability rating.

They are divided into the following subclasses:

• Standard

• High-temperature resistant, suitable for lead-free tinning and soldering

• Halogen-free, without phosphorus and antimony

• With normalized CTI index ≥ 600

• Waterproof, with increased dimensional stability

CEM-3

CEM-3 is a family of materials according to the NEMA classification. It is a composite material based on epoxy fiberglass typically in milky-white or transparent color. It is often used for the production of double-sided printed circuit boards. In terms of properties, it is very similar to FR-4 and only differs in slightly lower mechanical strength. It is a cheaper alternative to FR-4 for the absolute majority of applications. These materials are well-suited for mechanical processing (milling, cutting). They have a UL94-V0 flammability rating.

Depending on their properties and application, CEM-3 is divided into the following subclasses:

• Standard, with or without ultraviolet (UV) blocking

• High-temperature resistant, suitable for lead-free tinning and soldering

• Halogen-free, without phosphorus and antimony

• With normalized CTI index ≥ 600

Here are the composite laminates CEM-1 and CEM-3 used in our production, along with their typical parameters.
(You can download datasheets for these materials via the link):

Manufacturer/Brand	Glass transition temperature Tg	Dielectric constant Dk	Datasheet
CEM-1 laminates
KingBoard KB5150H	140°C	4,2	Download
CEM-3 laminates
coming soon...			Download

Detailed specifications and datasheets for materials used in high-frequency printed circuits

For the production of printed circuits operating in high-frequency and microwave ranges, specialized laminates with low dielectric loss (Df) and a dielectric constant (Dk) in the range of 2-3 are used. Materials meeting these requirements often include PTFE composites, thermosetting materials with ceramic fillers, and laminates on ceramic substrates. For less demanding applications, modified FR-4 laminates designed for high-frequency ranges (High Frequency FR-4) are used.

PTFE (Teflon)

Materials based on fluorocarbon compounds reinforced with glass fiber. Printed circuits made on such materials have increased reliability, electrical strength, moisture resistance, and can operate at high temperatures. These materials are widely used in the production of linear power amplifiers, antennas for communication systems, including satellite systems, as well as other radio communication elements. Additionally, these materials have found application in fast digital applications where signal integrity and accuracy are a priority.

RO3000

A series of materials developed for wide application in the early 1990s. These materials have excellent electrical properties in the very high-frequency range. The coefficient of thermal expansion (CTE) along the X and Y axes for these materials is similar in value to the CTE of copper and FR4, enabling the production of reliable RO3000/FR4 hybrid assemblies. Low dielectric losses (Df ~ 0.0013 at 10 GHz) are a significant advantage when using laminates from this series in microwave devices.

RO4000

This is a series of materials for use at high frequencies. They were developed to provide quality parameters for very high-frequency ranges, comparable to materials containing polytetrafluoroethylene (PTFE), while simplifying the production technology of boards to be in line with traditional processing of reinforced laminates (FR4). The RO4000 materials consist of high-temperature glass fiber (Tg ~ 280 °C) with a thermosetting polymer filler with the addition of ceramics.

Materials for high-frequency applications used in our production and their typical parameters
(you can download datasheets for these materials via the link):

Manufacturer/Brand	Dielectric loss factor Df	Dielectric constant Dk	Datasheet
PTFE laminates
Arlon AD10	0,0078	10,2	Download
Arlon AD255A	0,0014	2,55	Download
Arlon AD350A	0,0030	3,50	Download
Arlon AD1000	0,0023	10,2	Download
Arlon DiClad 527	0,0010	2,5	Download
Arlon DiClad 870	0,0009	2,33	Download
Arlon DiClad 880	0,0008	2,18	Download
Rogers RT\duroid 5870	0,0005	2,33	Download
Rogers RT\duroid 5880	0,0004	2,20	Download
Taconic TLY Series	0,0009	2,17-2,33	Download
Laminates with ceramic filler
Arlon 25N/25FR	0,0025-0,0035	3,38-3,58	Download
Rogers RO3003	0,0013	3,0	Download
Rogers RO3006	0,0020	6,15	Download
Rogers RO3010	0,0023	10,2	Download
Rogers RO4003C	0,0027	3,38	Download
Rogers RO4350B	0,0037	3,48	Download
Rogers RO4450B	0,0040	3,30-3,54	Download
Taconic RF-10	0,0025	10,2	Download
Taconic RF-35	0,0018	3,5	Download
Taconic RF-60A	0,0028	6,15	Download
Taconic TSM-DS3M	0,0011	2,94	Download
Laminates with ceramic substrates
Rogers TMM3	0,0020	3,27	Download
Rogers TMM4	0,0020	4,5	Download
Rogers TMM6	0,0023	6,0	Download
Rogers TMM10	0,0022	9,2	Download
Rogers TMM10i	0,0020	9,8	Download
Rogers TMM13i	0,0019	12,85	Download
Taconic HF-300	0,0016	3,0	Download
FR-4 laminates for High Frequency ranges
Shengyi S7136H	0,0030	3,61	Download
TUC TU-872 SLK	0,0100	3,5	Download

Detailed parameters and datasheets of materials for flexible and rigid-flex printed circuits

Flexible and rigid-flex printed circuits are becoming increasingly popular. The use of such printed boards allows for increased reliability of connections, integration with complex enclosures, and reduction in the dimensions and weight of devices.

For the rigid parts of rigid-flex printed circuits, the same materials are used as for conventional multilayer printed circuits. However, for flexible parts or standalone flexible printed circuits, special materials such as polyimide or PET are used.

Polyimide

It is a flexible polymer film that serves as the substrate for flexible printed circuits. There are several formulations of polyimide available under commercial brands like Kapton, Rogers, Dupont.

Advantages:

• Excellent flexibility at all temperatures

• Good electrical properties, excellent chemical resistance (except for hot concentrated alkali)

• Very good tear strength

• Operating temperature from -200°C to +300°C

Some types of polyimides have additional advantages (e.g., coefficient of expansion matching those of copper)

Disadvantages:

• High water absorption (up to 3% by weight)

• Relatively high price

  Despite its high glass transition temperature, the high-temperature properties of polyimide-based boards are limited by adhesives for bonding layers.

The thickness of polyimide film can vary widely, but in practice, most offered flexible materials have a thickness in the narrow range of 12 to 125 μm. When designing flexible printed circuits, the following principle can be useful: the stiffness of flexible materials is proportional to the cube of their thickness. This means that if the thickness of the material is doubled, it becomes eight times stiffer, and at the same load, it will deform eight times less.

PET

Polyethylene terephthalate (PET) can also be used as a flexible material. However, due to its low melting temperature, the possibilities for soldering on this material are significantly limited. PET is a good dielectric, has high chemical resistance to acids and bases, and increased resistance to water vapor. The mechanical properties of copper-coated PET films are better in terms of tear strength, dielectric constant, and insulation resistance. Operating temperature range from -60°C to +105°C.

These films also have the following advantages:

• It is a low-temperature thermoplastic (easy to shape)

• It has very good flexibility

• Good electrical properties

Disadvantages:

• Limited solderability (has a low melting temperature)

• Cannot be used at very low temperatures (becomes brittle)

• Insufficient dimensional stability.

Materials for flexible and rigid-flex PCBs used in our production and their typical parameters
(you can download datasheets of the materials via the link):

Manufacturer/Brand	Glass transition temperature Tg	Dielectric constant Dk	Datasheet
Polyimide
Panasonic RF770, RF775	343°C	3,2	Download
Shengyi SF302	>280°C	3,5	Download
Shengyi SF305	>280°C	3,6	Download
ThinFlex A-3005RD	350°C	3,3	Download
ThinFlex A-3010RD	350°C	3,3	Download
ThinFlex A-4005RD	350°C	3,3	Download
ThinFlex A-4010RD	350°C	3,3	Download
ThinFlex W-2005RD-C	350°C	3,3	Download
ThinFlex W-2010RD-C	350°C	3,3	Download
PET
Jiu Jiang LPET	100°C	3,3	Download

Detailed parameters and datasheets of materials for printed circuits on metal substrates

To enhance heat dissipation in a printed circuit, a laminate with a metal substrate, such as aluminum coated with a dielectric, can be used. These materials are employed to improve the heat dissipation from assembled components, particularly in electronic equipment with high operating currents at elevated temperatures. We can offer the production of single- and multi-layer printed circuits on aluminum substrates with various thermal conductivity and breakdown voltage values.

Materials on aluminum substrates used in our production and their typical parameters
(datasheets for these materials can be downloaded from the link):

Producent/Nazwa	Thermal conductivity λ (W/m*K)	Breakdown Voltage	Datasheet
Boyu AL-01-P	0,6 – 0,8	3kV	Download
Boyu AL-01-A	1,0 – 1,8	3kV	Download
Boyu AL-01-B	2,0 – 2,8	3kV	Download
Boyu AL-01-L	3,0	3kV	Download
GoldenMax GL12	0,8 – 1,0	4kV	Download