Isola Laminate Expert

Isola Laminates: The Ultimate FAQs Guide

This is the most comprehensive guide on Isola laminates.

It answers all questions you have been asking about Isola laminates.

Keep reading if you want to be an expert on Isola PCB materials.

What is Isola Laminate?

Isola laminates are high-performance PCB laminate materials featuring proprietary resin formulations.

The design of these laminate fulfil most demanding performance requirements in complex PCB.

Such PCBs are common in highly demanding electronic devices.

PCB Laminate

Which are the Types of Isola PCB Laminate?

Here are the main categories of Isola laminates available in the market:

· High-Speed Digital Laminate

There are a wide variety of High-speed Digital (HSD) Isola laminate materials that offer superior CAF resistance and performance.

These low-loss PCB laminates are ideal for applications requiring high signal integrity and reliability.

Additionally, you can as well find halogen-free HSD Isola PCB laminates for green electronics.

You should consider factors like the high-speed digital channel length and maximum data rate when selecting a laminate.

Example of High-speed digital Isola Laminates include:

• Tachyon 100G
• IS415
• TerraGreen
• FR408HR
• I-Tera MT40
• I-Speed

High Thermal Reliability Laminates

There are Isola laminate materials having a different degrees of electrical performance while also ensuring exceptional thermal reliability.

The introduction of lead-free PCB assembly has led to need for high thermal reliability laminates because of their high assembly temperature.

Furthermore, you also need thermally robust laminates for PCB applications involving harsh operating conditions.

Examples of High Thermal Reliability Isola laminates include:

• IS400HR
• Astra MT77
• P95/P25
• Tachyon 100G
• I-Tera MT40
• FR408HR
• TerraGreen
• 370HR
• 185HR
• P96/P26
• I-Speed
• IS400
• IS415
• IS420

RF/Microwave Laminates

Dielectric in PCB

This type of Isola laminate ensures precise control of dielectric thickness, dielectric constant and line widths.

This makes you achieve optimal signal performance in your RF/microwave PCB application.

Examples of RF/Microwave Isola Laminates:

• IS680 AG -348
• Astra MT77
• TerraGreen
• IS680 AG
• I-Tera MT40
• IS680

Halogen-Free Laminates

This type of Isola laminate helps you meet the increased performance requirements and need for eco-friendly designs.

Furthermore, halogen-free PCB laminates ensure thermal reliability to sustain the harshness of soldering conditions.

These PCB laminates also have high chemical resistance to endure etching and plating processes.

Examples of Halogen-Free Isola Laminates

• TerraGreen

High-Density Interconnect Laminate

 HDI PCB

HDI PCB laminates help you in the construction of circuit boards featuring high components density.

This enables to attain thinner stack-ups, lighter weight and decreased layer count.

Isola laminates of this type facilitate multi-track routing of fine pitch and high I/O electronics.

They offer thermally robust performance needed for sequential cycles of lamination of complex PCBs.

The laminates apply spread glass technology instrumental in enhancing vital feature registration, dielectric thickness control and consistency in laser ablation.

Many high-performance HDI Isola laminates feature a thickness of as low as 0.02 mm.

Examples of HDI Isola Laminates

• Tachyon 100G
• FR408HR
• I-Tera MT40
• IS415
• I-Speed
• 370HR

Are there Lead-Free Isola Laminates?

Yes.

You can find Lead-Free Isola laminates capable of enduring the high temperatures of soldering and reflow.

Their characterization depends on thermal resistance (T288 and T300), Glass transition temperature (Tg), Time to Decomposition (Td) and general CTE.

IS410 is an Isola high-performance laminate engineered for lead-free soldering and ensures higher degree of reliability.

IS 410

The PCB laminate has a Tg of 180 degrees Celsius and guarantees excellent performance via several thermal excursions.

The Lead-Free laminate is honed for improved drilling performance, enabling high holes aspect ratio of ≤10 mils.

Featuring a unique resin chemistry, it offers CAF resistance thus guaranteeing long-term reliability of PCB.

Which are the Key Features to Consider when Choosing Isola Laminate?

Here are the main properties of the Isola laminate you should consider when selecting dielectric material for your PCB application:

1) Glass Transition Temperature (Tg)

This refers to the temperature where the laminate changes to a viscous condition from solid-state.

It is a very important parameter when choosing PCB laminate material.

2) Thermal Decomposition Temperature (Td)

You should factor in the Td of Isola laminate since it determines the temperature where the PCB material degrades chemically.

3) Dielectric Constant (Dk)

The dielectric constant of laminate establishes the speed of transmission of the electrical signal within the dielectric material.

4) Loss Tangent (Tanδ)

You should consider this parameter as it determines signal power loss as it travels via transmission line on the Isola laminate.

5) Coefficient of Thermal Expansion (CTE)

CTE of the PCB laminate as it helps you in knowing the material dimensional changes due to temperature changes.

6) Thermal Conductivity (Tc)

It is also important to factor in the thermal conductivity of the dielectric material, which measures it characteristic in heat conduction.

What is the Relationship between Glass-to-Resin Ratio and Dielectric Properties of Isola Laminates?

Typically, PCB laminates are composite materials consisting of copper foil, reinforcement and resin matrix.

There are various theoretical models for predicting the dielectric properties of Isola PCB laminates.

In these models, it is most essential to understand the dielectric features of the reinforcement and resin.

Generally, the primary factor affecting the consistency of the laminate dielectric properties is the glass-to-resin ratio variation.

The measured Df and Dk will change in case you vary the laminate thickness by removing or adding resin.

Thicknesses variation are typical because of differences in resin weight per unit area of Isola laminate and glass fabric dielectric thickness.

Resin dielectric properties have an instrumental role in establishing the general dielectric features of the PCB laminate.

Isola laminates manufactured using resin systems with lower Df values compared to glass display lower Df with thinner glass.

Conversely, resin systems having higher Df compared to glass offer higher Df figures with thinner glass.

Does Humidity Affect the Performance of Isola Laminate?

Humidity makes one of the highly destructive enemies of PCB laminates.

As per IPC 4101C, the moisture level in Isola laminate should never surpass 0.8 percent in the material.

Excessive absorption of moisture decreases the laminate performance characteristics such as glass transition temperature.

Moreover, humidity increase the chances of CAF and defects risk during thermal processing like delamination.

Furthermore, humidity can as well affect the performance of Isola PCB.

If you utilize a laminate that is prone to moisture absorption, the moisture can affect impedance stability and loss performance.

 Controlled impedance PCB

Most PCB laminates feature 2 percent or more moisture absorption values.

This implies that they can absorb moisture easily in a humid condition changing the electrical properties of the laminate.

The dielectric constant of water is exceptionally high (around 70) in comparison to PCB laminate materials.

Therefore, excessive absorption of moisture can increase the Dk of the Isola laminate and raise its dielectric loss.

However, Isola PCB laminates designed for high-frequency circuit board applications usually feature low moisture absorption.

What are the Applications of Isola Laminate?

The common uses of Isola laminates include integration in a number of advanced electronics consisting of:

• High-end consumer electronics
• Network and communications devices,
• Advanced automotive applications
• Medical equipment
• Military equipment
• Avionics

Which are the Techniques of Testing Dielectric Properties of Isola Laminate?

PCB suppliers apply several methods for characterizing PCB laminates.

These techniques include:

· Parallel Plate Technique

In this method, you sandwich the Isola laminate between 2 electrodes to create a capacitor.

The technique can use an impedance analyzer or LCR meter to take the measurements.

This technique of measuring dielectric typically uses low frequencies (less than 1 GHz).

In the test, you derive results by considering the material dimension and by determining its dissipation factor and capacitance.

· Two fluid Cell Method

The technique uses air as one fluid and an appropriate liquid, usually Dow 200 1.0CS silicone fluid. Applying an established air permittivity value, you can easily calculate the fluid and Isola laminate permittivity value.

The cell spacing is constant during all readings, however it is not mandatory to know it accurately during the required readings.

This is a very fast and accurate method of measuring dielectric of PCB laminates.

You can measure several laminates at a go without machine setting or spacing adjustment. Moreover, two fluid cell technique require no electrodes.

· Split Post Cavity Resonator

The SPDR method offers an accurate technique of measuring the sophisticated permittivity of low loss Isola laminate materials.

It measures complex permittivity difficult to determine through other methods.

SPDR works at TE01δ mode that limits the electric field elements within the azimuthal direction.

This ensures that electric field stays continual on the interfaces of the laminate.

The resonance mode does not sense air gaps presence perpendicular to the laminate’s longitudinal axis.

You determine laminate permittivity from the shift in resonance frequency because of inserting it in the split post gap.

You can establish the loss tangent from an empty cavity Q factor and that of a cavity containing sample, respectively.

· IPC X-band Stripline

This technique helps in measuring the X-band detectable relative stripline loss tangent and permittivity of Isola metal-clad laminates.

You make the measurements under stripline conditions utilizing a resonant component pattern card.

The Isola laminates to be tested separately the pattern card from ground planes.

·  Bereskin Stripline

The method is able to characterize loss tangent and permittivity of Isola PCB laminates as a frequency function.

It applies a stripline configuration, having probes touching conductor planes.

These conductor planes sandwich the copper strip and laminate material under test.

Equally spaced from the fixture center, the probe initiates and senses oscillations on the Bereskin stripline.

This dielectric testing method needs a minimum thickness of laminate that precludes thin dielectrics measuring.

The technique is useful since it helps you determine the laminate electrical properties at any content of resin.

· Full Sheet Resonance Technique

The FSR method helps is a non-destructive means of measuring the relative permittivity of Isola metal-clad laminate materials at microwave frequencies.

It is suitable for laminates having dielectric covered with metal foil on either surface.

It can also test a laminate having a thick metal cover on one surface and metal foil cladding the other surface.

Different from methods applying microstrip resonator or stripline, this technique is sensitive to the permittivity of laminate only in the Z-axis.

You can use it to compare Isola laminate’s permittivity of essentially equal dimensions.

What is the Difference Between the Dissipation factor and Dielectric Constant of Isola Laminate?

The dielectric constant (Dk) is among the important properties of an Isola laminate material.

Dk represents a measure of energy between conductor pair around the laminate in comparison to that of the conductor pair in vacuum.

The vacuum value is 1.0, while the value of any other PCB laminate being greater than that.

An Isola laminate having higher Dk values can keep more energy than those having lower Dk values.

However, higher Dk values will lead to slower flow rate of electromagnetic energy across the conductors.

Conversely, the dissipation factor (Df) measures rate of energy loss of an oscillation mode within a dissipative system.

Df is reciprocal of Q (quality factor), which denotes oscillation quality.

Df factor is important since it enable you to determine the frequency performance of the Isola laminate.

How Do you Test the Quality of Isola Laminate?

Here are some of the ways of performing quality analysis of Isola laminate:

· Peel Test

The aim of this test is to establish adhesive strength of the Isola laminate or adhesive bond strength between laminates.

It is normally applied to measure strength of adhesion between two flexible and a rigid and flexible laminate.

You can use the measured value to establish whether the adhesive bond is sufficiently strong or exceedingly strong.

It also helps in determining if you need a different bonding procedure or adhesive.

The common forms of peel tests for PCB laminates include 90 degree peel, T-peel and 180-degree peel.

· Swell Test

In this test, you determine the extent of swelling of the Isola laminate due to absorption of moisture.

It is important because epoxy resins applied in PCB laminates are hydrophilic, hence will absorb water during operation.

This will make the laminate material to swell, which leads to dimensional changes that cause localized stresses.

You must factor in these stresses to prevent premature failures and lower than anticipated reliability.

· Lap Shear Test

Lap shear testing is consider a sub-class of peel testing.

The test is usually applied to establish the strength of adhesion between PCB laminates.

In this method of testing quality of Isola laminates, you bond two laminate materials and then pull them apart.

Typically, to allow calculation of Mpa and PSI, you must define the surface are you have applied adhesive.

There are different forms of lap shear test, and you must consider what a specific standard requires.

You can use double-butt lap shear, double lap shear, and single lap shear.

· Conductive Anodic Filament Testing

CAF testing aids you in establishing the reliability of the Isola laminate.

The need for this PCB laminate test is rising due to reducing conductor spacing and general component sizes.

The right environmental conditions for doing the test is under high humidity and temperature. Often, the standard test technique is IPC-TM-650, Method 2.6.25A.

Is there Difference Between the Thermal Coefficient of Dielectric Constant and Coefficient of Thermal Expansion of Isola Laminate?

All Isola PCB laminates feature a parameter referred to as thermal coefficient of dielectric constant (tCDk).

It defines the extent to which the dielectric constant of the laminate will change with temperature changes.

These modifications in Dk will as well alter the microstrip transmission lines impedance.

Therefore, you should opt for laminates with lower tick values that cause minimal impedance effects.

Besides, the Coefficient of Thermal Expansion (CTE) defines how much Isola laminate will expand or contract when you heat/cool it.

Each PCB laminate comes with a different CTE.

Therefore, this mismatch in CTE can cause issues the process of manufacturing Isola PCB.

This is because two PCB materials will expand to different degree when exposed to heat.

For that matter, you should keep the difference in CTE as low as practical.

It should be at minimum along the Z-axis, since expansion is higher along this direction.

What Dictates the Thickness of Isola Laminate?

Isola 370HR

The laminate thickness is a function of the type and number of prepreg layers it constitutes.

Each fabric style, if coated using resin to a specific weight, features a characteristic thickness.

You can calculate the thickness mathematically using the resin density and weight and fabric density and weight.

Controlling the overall weight is a more precise means of determining total Isola laminate thickness than just measuring resin content.

There is a possibility of having one fabric with differing finished weights that will create different finished thicknesses of laminate.

Can you V-score High-frequency Isola laminate?

No, since high-frequency Isola PCB laminates incline to be fibrous and soft.

You that a V-score consists of 2 round saws facing one another.

Therefore, the high-frequency PCB laminate will not endure the V-scoring process.

V score in PCB

Which are the Materials Used in Isola Laminates?

The basic PCB materials used in Isola laminates comprise of:

· Fiberglass

You can find fiberglass fabric in various roll thicknesses and widths.

· Resin

The properties of the PCB laminate required dictate the type of resin you will use in the design.

It confers distinct physical, electrical, and thermal features to the laminate, which is instrumental to proper Isola PCB performance.

Your selected resin type should be feasible with the copper foil and fiberglass fabric.

· Copper

The foil type and weight designate the copper.

You can use standard electrodeposited, double treat, HTE, or reverse treat copper foil.

Moreover, the copper you use needs to have good peel strengths.

This ensures that it does not separate from the resin and glass.

· Prepreg

This is a dielectric PCB material that offers electrical insulation and supplementary properties.

You manufacture it by impregnating the fiberglass fabric with distinctly formulated resins.

PCB laminate manufacturers can integrate prepregs into an Isola copper-clad laminate or sell it independently.

Most laminates comprise of an inner prepreg layer laminated on either sides using a thin copper foil layer.

You achieve the lamination by compressing together prepreg and a single or more copper plies.

The lamination process takes place under intense pressure, heat and vacuum conditions.

Isola FR 406

· Mechanical Rigidity

Here, there are Rigid Isola Copper-clad laminate, Flex Isola copper-clad laminate, and Rigid-Flex Isola laminate.

· Insulation Material and Structure

These types of Isola CCL organic resin Copper-clad laminate, Metal-base Copper-clad laminate, ceramic-base Copper-clad laminate, etc.

· Thickness of Laminate

There are two main types including standard thickness Isola laminate and thin Isola PCB laminate.

Standard thickness laminate should have a minimum thickness of 0.5mm.

On the other hand, the thin Isola laminate can have a thickness lower than 0.5mm.

However, you should note that the thickness of the copper foil is not part of laminate thickness.

· Reinforcing Material

In this category, you can find fiberglass CCL, fabric-based CCL, paper-based CCL, and Compound CCL.

· Insulation Resin

Here there is epoxy resin Isola copper-clad laminate, polyimide Isola copper-clad laminate, and phenolic Isola copper-clad laminate.

What is the Importance of Thermal Stress in Isola Laminate?

This measurement helps you in evaluating the laminate thermal integrity after momentary exposure to solder.

It usually takes 10 seconds at 288 degree Celsius, where you assess the laminates for proof of delamination and blisters.

What are the Feature of the best Isola Copper-Clad Laminate?

Here are the main features you should consider when selecting the best Isola copper-clad PCB laminate:

· Surface Roughness of Laminate

Surface roughness of the best Isola PCB laminate should be flat and smooth.

Resin point, bubble, wrinkle, scratch, wrinkle, pinhole and dent can lower the laminate performance.

· Size of Laminate

The Isola laminate you choose should conform to the corresponding PCB size requirements.

You need to consider warpage, length diagonal deviation and width when choosing the right size of Isola copper-clad laminate.

· Electric Performance of PCB Laminate

You must consider the following key parameter affecting the electrical performance of Isola PCB laminates:

• Dielectric constant (Dk)
• dielectric breakdown voltage
• Dielectric loss tangent (Df)
• electric strength
• volume resistance
• Comparative Tracking Index (CTI)
• surface resistance
• arc resistance
• insulation resistance

Physical Performance

Parameters to consider to determine the physical performance of Isola copper-clad laminates include:

• Bending strength
• Heat resistance
• Dimensional stability
• Peel strength
• Punching quality

Chemical Performance

The PCB laminate you choose must fulfill the requirements of:

• Flammability
• Glass Transition Temperature
• Chemical reagents resistance
• Z-Coefficient of thermal expansion
• Dimensional stability

Environmental Performance

The laminate material must meet the requirements in relation to moisture absorption.

Which are the new Trends in Isola Copper-Clad Laminates?

To comply with RoHS standards, there is a higher requirement on PCB laminates with regards to reliability and heat resistance.

Here are the two main emerging trends in Isola laminates:

Halogen-Free Isola Laminates

This refers to It refers to Isola copper-clad laminate whose content of bromine and chlorine is controlled around 900 ppm.

In addition, the general content cannot exceed 1500 ppm.

Lead-free CCL

In this type new type of Isola laminate, you perform the surface mounting using lead-free solder.

Brominated epoxy resin is the primary copper-clad laminate resin.

The curing agent used in Lead-Free laminates is Phenol-formaldehyde resin.

What are X, Y and Z Axes of Isola Laminate?

The X, Y and Z axes makes up the “Cartesian Coordinates” of an Isola laminate.

The X-direction represents the warp direction of the laminate prepreg.

Likewise, the Y direction corresponds to the fill direction of the fiberglass fabric.

On the other hand, Z axes refers the direction perpendicular to the laminate plane as designated by X and Y.

You refer to the X and Y directions when talking about prepreg orientation in the laminate for purposes of layup.

Also, when measuring dimensional stability or in-plane CTE of the PCB laminate.

Conversely, the Z direction is usually the drilled holes direction.

Vital issues of reliability of plated through hole always relate to the laminate thermal expansion along the Z-direction.

Which is the Best for Isola Laminate Between Rolled Copper and Electrodeposited Copper Foil?

The standard copper utilized in the laminate sector is electrodeposited copper foil.

Deposition of ED foil happens from a formulation at a specific current and voltage onto a moving steel or titanium drum.

The grain structure developed through this process creates the copper foil dendritic tooth on the bath edge” of the copper.

Also, the drum edge assumes the smoothness of the drum surface.

Besides, you make rolled copper by passing a copper strip across sequentially smaller and smaller gaps within a rolling mill.

It goes through this process until you achieve the required thickness.

Rolled copper has a smoother surface and you can make it very flexible through annealing.

Its smoothness makes its bond to Isola laminate depends on the treatment quality and adhesive features of the resin system.

Moreover, rolled copper equally features a different grain structure in comparison to ED copper.

Therefore, its etching rate will as well be different.

Typically, rolled copper foil find application in flexible PCB laminates, normally bonded using an acrylic adhesive to a polyimide layer.

It also finds use in RF and microwave applications in which its polished surface allows the manufacturing of PTFE laminates.

Rolled copper laminates have very low dissipation factor in comparison to ED copper foil due to surface effect.

At microwave frequencies, the electrical signal behaves as if it follows the copper profile at the dielectric interface.

Being rougher, ED copper exhibits an extended pathway compared to smooth rolled foil, thus greater loss.

However, there exist low profile copper foil varieties that offer cost benefits over roller copper.

They also give significant advantages over ED copper with regards to:

• Copper adhesion to several resin systems
• Faster etch rate
• Reduced dielectric loss etc.

How do you Ensure Copper Adhesion in Isola Laminate?

You can attain copper adhesion in Isola laminates by a blend of chemical and physical bonding.

ED copper features a natural tooth structure that gives a locking means during the coating and encapsulation by resin.

It is possible to improve bonds through chemical treatment of copper.

Most foils in applications currently have exclusive silane or supplementary treatments that improve bond to a number of resins.

However, not all copper foils will blend perfectly with all resins.

Therefore, lamination process optimization and foil finish selection for every resin system is important to attaining good bonds.

Which are the Crucial Process Parameters when Manufacturing Isola Laminate?

Are there Flame Retardant Isola Laminates?

Yes, among the various Isola laminate types, FR-4 are flame retardant type of Isola copper-clad laminates.

They feature fiberglass fabric as their substrate and modified epoxy or brominated epoxy resin as the adhesive.

FR-4 Isola laminates have high dielectric features, excellent thermal resistance and high strength.

This is because there has been increased demand for laminates with high thermal resistance.

Because of this, flame-retardant Isola laminates are among the most popular types of PCB laminates used today.

How are Isola Copper-Clad Laminates Categorized?

You can categorize Copper-clad laminates into various groups based on different classification standards including:

 Isola PCB

You should be keen on 5 specific areas associated with the selection of laminate materials.

They are important irrespective of the material though specific suggestions might be different for filled, low-flow, epoxies or polyimide systems:

• Maintain processed interior layers and prepreg dry before lamination.
• Control of rate of heat up within the laminating pressure to make sure there is regular melt flow.
• Ensure the right temperature of lamination for the Isola laminate you are using.
• Make sure the cure time is sufficient to develop Tg.
• Regulate cool down to avoid warpage.

How is Registration Important in Isola Laminate?

Curing of laminate constituents happens at temperatures exceeding the service temperature.

This causes internal stresses during cooling back to room temperature.

Therefore, the curing and cooling process initiates dimensional changes in the Isola laminate and movement of conductive copper tracks.

These changes will ultimately lead to a connection flaw in the laminate thickness.

So, it is critical to have knowledge in both your equipment capabilities and the physical characteristics of the Isola PCB laminate.

Depending on the CTE values of the materials, every material expands at differing rates during lamination.

This can lead to significant registration problems as one material expands while the other contracts.

The expansion and contraction can cause copper-to-substrate interface delamination.

Which are the Common Dielectric Materials Used in Isola Laminate?

Manufacturing of Isola laminates take place under high pressure and comprise of thermoset resin and paper or cloth layers.

You can produce laminates to satisfy custom properties, with Tg, shear, and tensile strength and CTE being the key features.

Here are the most common dielectrics for Isola laminates:

Ceramic Material

Alumina or aluminum is the most common type of ceramic dielectric material used in PCB laminates.

It is a sturdy thermal dielectric having a low expansion and ensures outstanding high-frequency performance.

The operating temperature of Alumina can go up to 350 degrees Celsius.

FR-4 material

This is a versatile and low cost Isola PCB laminate material manufactured from layers of prepreg.

The materials used to construct the prepreg include fiberglass fabric impregnated using epoxy resin.

It is the standard dielectric material in the laminate industry due to its ease of metallization and drilling.

FR4 material ensures low-cost manufacturing of PCB laminates, guaranteeing excellent performance at microwave/RF frequencies.

CEM-1

Short form for Composite Epoxy Material, CEM-1 is a cheaper option for FR-4 as it costs far less.

The dielectric consist of phenol compounds and two woven glass epoxy layers.

CEM-1 is good for the manufacturing of single-sided Isola PCBs, since it is not compatible with the metallization process in holes.

Its properties are similar to those of FR-4 materials, though CEM-1 has poor mechanical endurance, with a Flammability rating of UL94-V0.

Polytetrafluoroethylene (PTFE)

Teflon is the most popular PTFE-based brand.

The Isola laminate material gives low dissipation factor and temperature stability.

Polyimide

Polyimide materials feature wide temperature range, good electrical properties and high chemical resistance.

How can you Improve the Registration of Isola Laminate?

Here are the ways of enhancing the registration of Isola laminate:

• Use materials that are dimensionally stable and comply with the laminate thickness requirements.
• Whenever possible, utilize heavier weight prepregs to aid in the stabilization of the whole system.
• Depending on your experience, determine artwork compensation values starting point for the resin you utilize often.

For thin polyimides, the range will be 0.2 to 0.3 and 0.4 to 0.6 mils/inch for cross and long direction of warp.

For epoxy resins, the values are almost half of polyimide systems.

• Make sure that all artwork takes place within a controlled humidity and temperature conditions.
• Produce the Isola laminates having registration in mind.

Do not use inner layers having too much copper on a particular edge, which might lead to skewing.

Utilizing copper borders assists in stabilizing the laminate against distortion.

• You should perform lamination at the lowest temperature suitable for the resin system. This is because higher temperatures cause more X-Y movement when laminating and more strains during cooling.
• Cool the PCB laminates at or lower than 5 degree Celsius to prevent “locking in” uneven stresses.

What is the Permissible Thickness Tolerance of Isola Laminate?

Thickness refers to the total width of the base laminate.

This includes in-process deposited coats, dielectric material and copper foil.

Due to this fact, the finished laminate thickness is usually greater than the thickness of base laminate.

IPC 4101 defines the permissible thickness tolerance of Isola laminates.

It describes 3 possible intervals of thickness spread.

Isola PCB laminates in the top class (C/M), have the narrowest tolerances.

They ensure high quality and repeatability of the fabricated PCB.

Circuit boards manufactured using Class C/M Isola laminates guarantee very high reliability.

Therefore, always consult your PCB manufacturer to choose the best structure and type of Isola laminate.

Clearly communicate whether the required thickness is for the finished laminate or the base laminate.

Also, remember that if you do not specify the tolerance, the PCB laminate manufacturer will apply their regular tolerance.

How is Comparative Tracking Index (CTI) Important in Isola PCB?

This is another feature of Isola laminate that describes the strength of breakdown between circuit tracks in wet environments.

Also, the unit for measuring the comparative tracking index of PCB laminates is volts (V).

There exist 6 performance level categories (PLC) of CTI.

The majority of PCB laminate suppliers use PLC3 as their standard.

The final product will be safer to use if you use laminate with the greatest PLC, with the maximum being PLC0.

Isola Laminates with High CTI are especially vital in high-voltage devices operated in elevated humidity environments.

They are as well ideal for high-voltage devices that get into direct contact with individuals.

Which are the Factors that Dictate the Thermal Properties of Isola Laminate?

Isola PCB

The thermal overloading of Isola laminates might lead to failure or permanent breakdown.

To guard against destructive over-temperature effects, you need laminates having thermal performance-tuned to the assembly process and ultimate operating conditions.

Here are the key factors that dictate the thermal properties of Isola laminates that you need to consider:

· Glass Transition Temperature

Represented as Tg, this temperature defines the point where there is a drastic decrease in mechanical features of Isola laminate.

This is due to transformation of the material from its glass state to a plastic condition.

The transition occurs concurrently with a swift increase in Z-direction expansion of the PCB laminate.

When you exceed this temperature, the mechanical loads exerted on the laminate will cause permanent delamination and deformation.

The load will also lead to reduced mosaic adhesion and copper foil lifting.

· Temperature of Decomposition

IPC 4101 describes Td as the temperature where the PCB laminate losses 5 percent of weight.

T260/288 represents time it takes to initiate delamination, measured if the material hits 260 or 288 degree Celsius.

· Coefficient of Thermal Expansion

You calculate the CTE of Isola laminate through the X-, Y- and Z-axis.

If it rises substantially above Tg, and the PCB laminate starts to swell swiftly.

This parameter is exceedingly instrumental to the performance of Isola laminate at elevated temperature.

The laminate expansion in the Z-direction leads to the conductor stresses at vias.

This leads to pads lifting and cracking of via holes or via edges.

The phenomena cause vias defects such as open circuit formation.

You can restore the electrical continuity through the vias intermittently.

For example, when you reduce the operating temperature of the Isola PCB laminate or the active mechanical forces.

Are There Quality Standards for Isola Laminate?

Yes, here are the quality standards that you should look for in an Isola laminate:

• IEEE Standards
• ASTM Standards
• IPC Standards
• ANSI Standard
• RoHS Standards
• IEC Standards
• PSTC-101 Standard

In short, before choosing Isola laminates, you must evaluate all properties I have mentioned in this guide.

In case you have any questions about Isola Laminates, feel free to contact Venture Electronics team.