01
Material identity
Confirm trade name, construction code, core/prepreg, thickness, glass style, resin content, and copper option. Request a certificate of conformity as a separate deliverable when the project requires it.
High-Speed Digital & RF Laminates
Isola PCB Materials and Fabrication
An Isola PCB is a printed circuit board whose laminate and prepreg construction is matched to the loss budget, impedance targets, thermal cycle, and via design. APTPCB fabricates Isola-material boards after reviewing the exact grade, core and prepreg, glass style, copper profile, stack-up, and acceptance evidence. Material selection does not replace channel simulation or end-product qualification.
370HR → Astra MT77
Material Range
Dk / Df + Method
Context-Rich Data
RFQ Release Gate
Controlled Build
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What the Buyer Is Specifying
An Isola PCB Is a Released Construction, Not Just a Brand Name
The Isola portfolio addresses different engineering problems. 370HR and FR408HR are thermally robust FR-4 systems with different loss levels; I-Speed and I-Tera MT40 target more demanding high-speed digital and mixed-signal designs; Tachyon 100G and Astra MT77 address ultra-low-loss digital and RF/microwave work. Isola publishes material-specific Dk, Df, Tg, and Td values with defined test conditions.
Material choice must be tied to the core and prepreg construction, glass style, resin content, pressed thickness, copper profile, trace geometry, and via architecture. Materials in a similar loss class are therefore not automatic substitutes. APTPCB confirms the proposed grade, hybrid construction, coupons, and evidence package after reviewing the input files for a high-speed PCB or RF build.
Selection Matrix
Which Isola Material Belongs on the Initial Shortlist?
Use this matrix to narrow candidates. It does not replace channel analysis, construction availability review, or a released stack-up.
| Material | Isola Positioning | When to Consider It | What to Recheck | RFQ Output |
|---|---|---|---|---|
| 370HR | High-performance 180 °C Tg FR-4 | A multilayer board where thermal reliability, CAF resistance, and a familiar FR-4 process are the priorities | Critical-channel loss, glass styles, finished thickness, and assembly thermal exposure | Confirmed core/prepreg, stack-up, and acceptance criteria |
| FR408HR | Lead-free, mid-loss laminate | Standard high-Tg FR-4 misses the loss budget, but an ultra-low-loss system is unnecessary | Model frequency, construction-specific Dk/Df, copper foil, and impedance geometry | Released stack-up and agreed impedance-coupon plan |
| I-Speed | Low-loss epoxy laminate | A high-speed digital board needs more insertion-loss margin than FR408HR provides | Channel length and topology, connectors, transitions, backdrill, glass weave, and copper profile | Material construction and channel-control points |
| I-Tera MT40 | Very-low-loss laminate and prepreg | A high-speed digital, RF/microwave, or mixed-signal board has a tighter loss budget | Exact Dk option, core/prepreg construction, hybrid boundaries, via architecture, and thermal profile | Fabrication review and a frozen material specification |
| Tachyon 100G | Ultra-low-loss laminate for very high-speed digital | A high-layer-count backplane or daughtercard makes conductor loss, skew, and transitions material to the channel budget | Spread-glass construction, copper profile, etch tolerance, backdrill, and correlation method | Release stack-up, coupon strategy, and evidence list |
| Astra MT77 | Ultra-low-loss RF/microwave laminate | RF, microwave, or mixed-signal sections need low Df with a thermoset material system | Operating frequency, RF geometry, thickness, copper, finish, transitions, and end-assembly qualification | Confirmed construction and project-specific RF/acceptance plan |
Availability of the exact grade, thickness, glass style, resin content, and copper option is confirmed in the RFQ. Alternatives require written approval.
Manufacturer Data
Isola Dk, Df, Tg, and Td With Test Context
The values below come from current Isola Group product pages. Frequency and method vary by material, so the numbers should not be compared without their test context.
| Material | Dk | Df | Frequency & Method | Tg, °C (DSC) | Td, °C (TGA, 5%) | How to Use the Data |
|---|---|---|---|---|---|---|
| 370HR | 4.04 | 0.021 | 2 GHz; Isola table, Bereskin Stripline | 180 | 340 | Preliminary high-Tg FR-4 comparison; use construction-specific data for impedance modeling |
| FR408HR | 3.68 | 0.0092 | 2 GHz; Isola table, Bereskin Stripline | 190 | 360 | Mid-loss screening; confirm model frequency and resin content for the selected construction |
| I-Speed | 3.63 | 0.0060 | 10 GHz; Isola table, Bereskin Stripline | 180 | 360 | Low-loss digital comparison; include glass-weave and copper-roughness effects |
| I-Tera MT40 | 3.45 | 0.0031 | 2–10 GHz; IPC-TM-650 2.5.5.5 / Bereskin Stripline | 215 | 360 | Starting point for very-low-loss or mixed-signal stack-ups; confirm the selected Dk option |
| Tachyon 100G | 3.02 | 0.0021 | 10 GHz; IPC-TM-650 2.5.5.5 / Bereskin Stripline | 215 | 360 | Preliminary ultra-low-loss digital model; include HVLP copper and transition behavior |
| Astra MT77 | 3.00 | 0.0017 | 10 GHz; IPC-TM-650 2.5.5.5 / Bereskin Stripline | 200 | 360 | RF/microwave candidate comparison; qualify the final geometry at the product frequency |
Source: Isola Group product pages for 370HR, FR408HR, I-Speed, I-Tera MT40, Tachyon 100G, and Astra MT77, accessed July 2026. These are typical values, not guaranteed finished-channel parameters. Check the current datasheet and construction table before release.
Substitution Boundaries
Why Similar Loss Values Do Not Make Laminates Interchangeable
Changing laminate affects more than loss. It can change impedance, trace width, pressed thickness, registration, drilling, copper profile, and assembly qualification.
| Scenario | Why It May Be Considered | Why It Is Not Drop-In | What Must Be Re-Released |
|---|---|---|---|
| 370HR → FR408HR | Lower Df is needed while staying in an FR-4 material family | Dk/Df, Tg, prepreg constructions, and final geometry differ | Stack-up, impedance table, and thermal profile |
| FR408HR → I-Speed | The channel needs additional loss margin | The electrical model, available glass styles, and conductor calculation change | Channel model, trace geometry, and coupon |
| I-Speed → I-Tera MT40 | A tighter insertion-loss budget or mixed-signal layer is required | A specific Dk option must be selected and lamination/via architecture reviewed | Material specification and DFM release |
| I-Tera MT40 → Tachyon 100G | The design requires an ultra-low-loss digital channel | Copper profile, spread glass, thicknesses, and skew control become part of the model | SI model, stack-up, and validation plan |
| Astra MT77 ↔ Rogers / PTFE | The candidates occupy a similar RF/microwave loss class | Resin systems, Dk, copper, thicknesses, transitions, and processes differ | RF geometry, finish, transitions, and qualification coupon |
| Isola / Other-Material Hybrid | Use the higher-cost low-loss material only on critical layers | CTE, flow, cure, bonding interfaces, copper balance, and registration must be aligned | Lamination sequence and every material boundary |
A substitution is accepted only after engineering review and customer approval. A new material name without a new released stack-up is not an engineering release.
Path to Production
How an Isola PCB Moves From Files to a Released Stack-Up
The review starts with Gerber or ODB++, drill data, netlist, fabrication drawing, layer count, finished thickness, copper, proposed Isola grade, impedance targets, via requirements, backdrill, and assembly profile. A brand or grade name without the core/prepreg construction is treated as a material preference, not a production-ready specification.
The exact construction codes, glass style, resin content, copper foil, pressed thickness, lamination sequence, and permitted trace corrections are then agreed. For controlled impedance, define the target, tolerance, coupon, measurement method, and report format before release. Hybrid builds, laser vias, filled vias, and sequential lamination remain subject to DFM.
Production receives a frozen package: approved stack-up, material callout, drill/via notes, impedance table, surface finish, customer acceptance criteria, and evidence list. A material or construction change after release requires reapproval. This connects material selection to actual PCB impedance control instead of an abstract low-loss claim.
Release Gate
What Must Be Agreed Before an Isola PCB Is Released
These seven checkpoints turn a material preference into a repeatable manufacturing specification.
| Checkpoint | Customer Input | Engineering Review | Release Output |
|---|---|---|---|
| 1. Material & substitutions | Exact grade or acceptable shortlist | Available construction, approved alternative, manufacturer revision | Frozen material callout |
| 2. Core / prepreg | Target thickness and layer constraints | Glass style, resin content, pressed thickness, symmetry | Released stack-up |
| 3. Copper | Copper weight and critical RF/high-speed layers | Foil profile, finished copper, etch compensation | Agreed copper construction |
| 4. Impedance & loss | Targets, tolerance, frequency, and channel budget | Geometry, model, coupon, and measurement method | Impedance table and validation plan |
| 5. Via architecture | Drill map, aspect ratio, microvia, filled via, backdrill | Sequence, annular ring, stub, and metallization | Released drill/via notes |
| 6. Assembly exposure | Reflow profile, thermal excursions, high-mass components | Compatibility of material, finish, and construction | Fabrication/assembly constraints |
| 7. Acceptance evidence | Required certificates, coupons, microsections, and reports | Feasibility, sampling, format, and acceptance criteria | Agreed evidence package |
If a critical checkpoint remains open, price and schedule are preliminary. Final commercial and technical conditions are confirmed in the RFQ.
Manufacturing Controls
Six Controls That Reduce Risk in an Isola Stack-Up
The exact control plan depends on board complexity and is stated in the technical and commercial proposal.
02
Lamination plan
Review symmetry, copper distribution, pressed thickness, sequence, and material boundaries. Hybrid builds require specific review of flow, cure, and registration risk.
03
Drilling and hole preparation
Select drill program, aspect ratio, smear-removal route, and metallization for the actual construction. A manufacturer's FR-4-compatible processing statement does not replace board-specific DFM.
04
Etch and impedance
Agree trace width/space, finished copper, and permitted geometry adjustment before CAM release. Coupons and tolerances apply only when they are included in the order.
05
Microsection and plating
For higher-risk via structures, specify microsection, copper measurements, resin-fill checks, and evaluation criteria. Sampling and report format are agreed in advance.
06
Change control
Preserve the approved stack-up and material callout for repeat orders. Any core/prepreg, copper-option, or construction change requires notification and reapproval.
Evidence and Boundaries
What Fabrication Evidence Proves—and What It Does Not
A basic board release demonstrates conformance to the agreed manufacturing data: material callout, stack-up, dimensions, electrical continuity, and the visual criteria in the order. The RFQ can add an impedance coupon, microsection, plating measurement, dimensional report, material certificate, or other records when technically feasible.
TDR verifies the impedance of the specified coupon. VNA or S-parameter testing verifies only the agreed test vehicle and frequency range. Neither document alone guarantees insertion loss for the complete channel, SerDes operation, antenna performance, or system compliance; correlation also depends on connectors, transitions, launch design, stack-up, copper, length, and the customer's model.
APTPCB is responsible for building to the approved manufacturing package and agreed acceptance criteria. Electrical architecture, system-level compliance, RF/EMC performance, functional safety, and end-product qualification remain the customer's responsibility. Reference documents should be listed by revision in the RFQ, such as the current Isola product datasheet and construction table, IPC-TM-650 2.5.5.5 where applicable, and the project drawing or acceptance specification. Link those requirements to the PCB quality plan before release.
Applications by Engineering Problem
Where Each Isola Material Family Enters the Shortlist
The application suggests a starting point, not guaranteed suitability. Select the material and stack-up from the actual frequency, channel, environment, and qualification plan.
Data Center & Networking
Backplane, line card, and switch board
Evaluate FR408HR, I-Speed, I-Tera MT40, or Tachyon 100G against channel length, transitions, backdrill, connectors, skew, and copper profile.
Telecom
High-speed digital and mixed-signal board
Choose by loss budget and layer assignment. RF and digital sections may require different constructions and separate release decisions.
RF & Microwave
Antenna, feed network, and RF control
Consider Astra MT77 or I-Tera MT40 with operating frequency, geometry, copper foil, transitions, finish, and the measurement plan.
Automotive Electronics
Radar and high-reliability controller
Isola publishes Astra MT77 material guidance for automotive radar use. The customer qualifies the complete module under the applicable product program.
Test & Measurement
Load board, interface board, and measurement path
Repeatable impedance, loss correlation, connector launch, and a documented test vehicle matter more than the laminate's headline Df alone.
Industrial & Medical
Multilayer board with thermal and signal constraints
Shortlist 370HR, FR408HR, or a low-loss family from the combined thermal profile, interconnect density, and signal-integrity requirements. System qualification remains with the product owner.
Practical Selection
How to Specify an Isola Material Without Creating Avoidable Risk
Five engineering decisions and one complete RFQ package are more useful than choosing only by the lowest published Df.
1. Start with the channel budget, not the interface label
State channel length, topology, model frequency range, transitions, connectors, allowable insertion loss, and return loss. The same interface can require different materials when length or via architecture changes.
2. Separate thermal risk from electrical loss
Tg and Td help compare families, but reliability also depends on Z-axis expansion, via design, lamination count, and assembly profile. An ultra-low-loss material is not automatically a thermal-reliability solution.
3. Freeze the data used for impedance
Define single-ended/differential targets, tolerance, reference planes, and permitted CAM correction. Model with the selected construction's Dk, not a single headline value from a product page.
4. Control substitutions and hybrid boundaries
List approved grades and prohibit unreviewed substitution. For a hybrid, assign each material by layer and define thickness and registration constraints.
5. Define evidence before the order
Specify whether the project needs a material certificate, impedance coupon, microsection, plating measurement, dimensional report, or S-parameter test vehicle. A report not included before fabrication may be impossible to add later.
6. RFQ checklist for an Isola PCB
Attach Gerber or ODB++, drill data and IPC-356 netlist, fabrication drawing, layer count, finished thickness, copper, preferred Isola grade and approved alternatives, stack-up or stack-up constraints, impedance table, via/backdrill notes, surface finish, panel/quantity, assembly profile, and required acceptance records. For a hybrid board, identify the material assigned to each layer.
FAQ
Isola PCB Material and Fabrication Questions
How do I choose between 370HR, FR408HR, I-Speed, and I-Tera MT40?
Start with the channel loss budget and assembly thermal profile, then check available core and prepreg constructions, glass style, resin content, and copper foil. 370HR emphasizes thermal reliability for general multilayer FR-4, FR408HR lowers loss, I-Speed is a low-loss system, and I-Tera MT40 is very-low-loss. Make the final choice from channel analysis and a released stack-up, not from the interface name alone.
Can standard FR-4 be replaced with an Isola material without changing the layout?
No. A change in Dk, Df, dielectric thickness, resin content, glass style, or copper profile can alter trace width, spacing, impedance, loss, and lamination behavior. Re-release the stack-up and recheck critical channels before fabrication.
What do the published Isola Dk and Df values mean?
They are typical values measured at a stated frequency and with a stated test method. They help compare material families but do not guarantee the behavior of a finished transmission line. For modeling, use construction-specific data and include glass style, resin content, thickness, copper profile, and actual geometry.
Is Astra MT77 a drop-in replacement for Rogers RO4350B or PTFE?
No. Astra MT77 has its own Dk, Df, thicknesses, prepreg options, and processing constraints. Even when it fits the same loss class, recheck impedance, line width, transitions, copper foil, thermal processing, and RF qualification of the finished assembly.
Can several Isola materials be combined in one hybrid stack-up?
A hybrid construction can be considered after engineering review. The exact core and prepreg, resin content, pressed thickness, copper distribution, lamination sequence, and registration requirements must be defined. Materials are not automatically compatible simply because they share a manufacturer.
What inspection evidence can be requested for an Isola PCB?
An RFQ can specify a material certificate of conformity, electrical test, impedance-coupon results, microsection, plating measurements, dimensional report, or another project-specific evidence package. The deliverables depend on the construction and must be agreed before the order; individual tests are not implied by default.
What determines Isola PCB lead time?
Lead time depends on availability of the exact material construction, lamination count, via drilling or filling, impedance requirements, surface finish, and requested acceptance evidence. A firm schedule is confirmed only after the files and supply chain are reviewed for the specific RFQ.
What should I send for an Isola PCB quotation?
Send Gerber or ODB++, drill files and netlist, fabrication drawing, layer count, finished thickness and copper, preferred Isola grade or approved alternatives, impedance table, via and backdrill requirements, surface finish, quantity, assembly profile, and the required inspection reports.
Quick Shortlist
Compare Six Isola Material Families
Typical manufacturer data helps identify candidates; the exact construction and fabrication fit are confirmed in the RFQ.
Select an Isola Material
Choose a material to view its published properties and selection boundaries.
International RFQs
Use One Controlled Engineering Package Across Regions
For an international project, agree measurement units, applicable specifications, material certificates, export constraints, packaging, and logistics before release. Commercial terms remain RFQ-specific.
Europe
Drawings and acceptance requirements
State the applicable customer-standard revisions, units, certificate format, and traceability requirements before order release.
North America
Material callout and change control
Freeze manufacturer and grade, approved substitutions, construction revision, and the notification path for changes.
Asia-Pacific
Stack-up and manufacturing data
Provide Gerber/ODB++, drill data, netlist, impedance table, and fabrication drawing in the agreed units and coordinate system.
Other Regions
Shipping and constraints
Confirm ship-to address, Incoterms, packaging, export constraints, and the required shipment-document set before ordering.
Request a Verifiable Isola PCB Proposal
Upload the manufacturing files, material preference, stack-up constraints, impedance table, and required evidence. We will review the construction and return an RFQ with confirmed material options, process boundaries, and acceptance deliverables.