Product Description
1. Material Overview – I-Tera® MT40 (Isola)
I-Tera® MT40 is a very low-loss, high-performance modified epoxy/FR-4 resin system from Isola Group, reinforced with E-glass woven fabric. It is specifically engineered for high-speed digital and RF/microwave printed circuit designs where standard FR-4 falls short but PTFE or hydrocarbon materials are cost-prohibitive or difficult to process .
Key Material Characteristics
| Feature |
Benefit |
| Dk = 3.45 (stable ±0.05) |
Low and stable dielectric constant from 2–10 GHz – consistent impedance across frequency . |
| Df = 0.0031 |
Very low dissipation factor – minimizes insertion loss for high-speed serial links and RF front-ends . |
| Tg (DSC) = 215°C / DMA = 230°C |
High thermal stability – supports lead-free assembly and 260°C peak reflow . |
| Td = 360°C |
Excellent thermal decomposition resistance – robust for harsh operating environments . |
| Stable Dk from -55°C to +125°C |
Consistent electrical performance across temperature extremes – essential for outdoor and automotive applications . |
| FR-4 process compatible |
No sodium etch or plasma desmear required – standard FR-4 fabrication lines . |
| CAF resistant |
Prevents conductive anodic filament formation – critical for high-voltage, fine-pitch designs . |
| Multiple reflow capable |
Withstands multiple lamination cycles – supports HDI and sequential lamination . |
| RoHS compliant |
Meets environmental regulations . |
2. Material Datasheet – Consolidated Properties (I-Tera MT40)
| I-Tera® MT40 |
| Property |
Typical Value |
Units |
Test Method |
| Metric (English) |
IPC-TM-650 (or as noted) |
| Glass Transition Temperature (Tg) by DSC |
215 |
°C |
2.4.25C |
| Glass Transition Temperature (Tg) by DMA |
230 |
°C |
2.4.24.4 |
| Glass Transition Temperature (Tg) by TMA |
210 |
°C |
2.4.24C |
| Decomposition Temperature (Td) by TGA @ 5% weight loss |
360 |
°C |
2.4.24.6 |
| Time to Delaminate by TMA (Copper removed) |
A. T260 |
>60 |
Minutes |
2.4.24.1 |
| B. T288 |
| Z-Axis CTE |
A. Pre-Tg |
55 |
ppm/°C |
2.4.24C |
| B. Post-Tg |
290 |
ppm/°C |
| C. 50 to 260°C, (Total Expansion) |
2.8 |
% |
| X/Y-Axis CTE |
Pre-Tg |
12 |
ppm/°C |
2.4.24C |
| Thermal Conductivity |
0.61 |
W/m·K |
ASTM E1952 |
| Thermal Stress 10 sec @ 288ºC (550.4ºF) |
A. Unetched |
Pass |
Pass Visual |
2.4.13.1 |
| B. Etched |
| Dk, Permittivity |
A. @ 2 GHz |
3.45 |
— |
2.5.5.5 |
| B. @ 5 GHz |
| C. @ 10 GHz |
| Df, Loss Tangent |
A. @ 2 GHz |
0.0031 |
— |
Bereskin Stripline |
| B. @ 5 GHz |
| C. @ 10 GHz |
| Volume Resistivity |
C-96/35/90 |
1.33 x 10^7 |
MΩ-cm |
2.5.17.1 |
| Surface Resistivity |
C-96/35/90 |
1.33 x 10^5 |
MΩ |
2.5.17.1 |
| Dielectric Breakdown |
45.4 |
kV |
2.5.6B |
| Arc Resistance |
139 |
Seconds |
2.5.1B |
| Electric Strength (Laminate & laminated prepreg) |
45 (1133) |
kV/mm (V/mil) |
2.5.6.2A |
| Comparative Tracking Index (CTI) |
3 |
Class (Volts) |
UL 746A |
| ASTM D3638 |
| Peel Strength |
1 oz. EDC foil |
1.0 (5.7) |
N/mm (lb/inch) |
2.4.8C |
| Flexural Strength |
A. Length direction |
490 (71.0) |
MPa (kpsi) |
2.4.4B |
| B. Cross direction |
400 (58.0) |
| Tensile Strength |
A. Length direction |
269 (39.0) |
MPa (kpsi) |
ASTM D3039 |
| B. Cross direction |
241 (35.0) |
| Young's Modulus |
A. Length direction |
3060 |
ksi |
ASTM D790-15e2 |
| B. Cross direction |
2784 |
| Poisson's Ratio |
A. Length direction |
0.234 |
— |
ASTM D3039 |
| B. Cross direction |
0.222 |
| Moisture Absorption |
0.1 |
% |
2.6.2.1A |
| Flammability (Laminate & laminated prepreg) |
V-0 |
Rating |
UL 94 |
| Relative Thermal Index (RTI) |
130 |
°C |
UL 796 |
Note: Dk/Df values are stable from -55°C to +125°C up to W-band frequencies (75–110 GHz) .
Standard Availability
| Parameter |
Options |
| Standard Laminate Thickness |
10, 20, 30, 60 mil (0.25, 0.51, 0.76, 1.5 mm) – 0.254mm (10 mil) used here |
| Copper Foil Type |
HVLP (VLP2) ≤2.5 µm Rz JIS, RTF (Reverse Treat Foil), HTE Grade 3, Embedded resistor foil |
| Copper Weight |
½ oz, 1 oz, 2 oz (18, 35, 70 µm) – 1 oz used here |
| Glass Fabric |
E-glass, Square weave glass, Mechanically spread glass |
| Prepreg |
Available with tooling panels, moisture barrier packaging |
3. Custom PCB – Double-Layer I-Tera MT40 with Castellated Edges
This double-layer board demonstrates our capability to handle high-frequency material processing, HVLP copper foil selection, and castellated edge fabrication for module applications.
Basic Specifications
| Item |
Specification |
| Layer Count |
2 layers |
| Base Material |
Isola I-Tera MT40 – 0.254mm (10 mil) laminate |
| Finished Copper Weight |
1 oz / 1 oz (both top and bottom) |
| Copper Foil Type |
HVLP (VLP2) – ≤2.5 µm Rz JIS for low conductor loss |
| Surface Finish |
Immersion Silver – excellent for RF applications, low contact resistance |
| Solder Mask |
Green (both sides) |
| Silkscreen (Top) |
White, oil-free – clean, no contamination risk |
| Silkscreen (Bottom) |
None, oil-free – bare surface for optimal soldering |
| Panel Size |
108mm × 35mm (1 piece) |
Castellated Edges (Plated Edges)
Castellated holes are plated half-holes along the board edge, designed for solder-down module connections. They provide a visible solder fillet that can be inspected optically – a significant quality advantage over LGA (land grid array) connections .
HDI and Sequential Lamination Capability
I-Tera MT40 supports HDI microvia construction and sequential lamination processes. Its dimensional stability under multiple press cycles – a direct benefit of its glass-reinforced architecture versus PTFE – makes it more predictable in production than PTFE alternatives .
4. Why I-Tera MT40 for This Design?
| Requirement |
How I-Tera MT40 Addresses It |
| RF/microwave signal integrity |
Df = 0.0031 minimizes insertion loss – critical for RF front-end modules |
| Temperature-stable performance |
Dk stable from -55°C to +125°C up to W-band – essential for outdoor/automotive |
| Cost-effective alternative to PTFE |
FR-4 process compatible – no sodium etch or plasma desmear required |
| Low conductor loss |
HVLP copper foil (≤2.5 µm Rz) – reduces roughness-induced loss |
| Edge-mount module design |
Castellated edges enable reliable solder-down connection |
| Multiple reflow capability |
Supports sequential lamination and multiple assembly cycles |
| CAF resistance |
Prevents conductive anodic filament formation – long-term reliability |
Application Areas
- RF/Microwave Modules
- 5G Small Cells / Base Stations
- Automotive Radar Sensors
- High-Speed Digital Modules
- IoT / Wireless Modules
- Medical Devices
Q1: What makes I-Tera MT40 different from standard FR-4?
A: I-Tera MT40 offers significantly lower Dk (3.45 vs. ~4.5) and Df (0.0031 vs. ~0.015–0.020), higher Tg (215°C vs. 170–180°C), and stable Dk across temperature and frequency – all while remaining FR-4 process compatible.
Q2: Does I-Tera MT40 require special processing like PTFE materials?
A: No. Unlike PTFE, I-Tera MT40 does not require sodium etch or plasma desmear for through-hole preparation. It processes using standard FR-4 fabrication techniques.
Q3: Why choose HVLP copper foil for this design?
A: HVLP (VLP2) copper has ≤2.5 µm surface roughness (Rz JIS) , reducing conductor loss at high frequencies. For RF/microwave layers operating above 5 GHz, HVLP is strongly preferred over standard HTE foil.
Q4: What are castellated edges, and why are they used?
A: Castellated edges are plated half-holes along the board edge, enabling solder-down module connections. They provide a visible solder fillet that can be optically inspected – a significant quality advantage over LGA connections.
Q5: What is the minimum drill diameter for castellated holes?
A: Minimum 0.6mm recommended, with 0.8–1.0mm preferred for hand-soldering rework. The routing cut must pass through the exact center of each drilled hole.
Q6: Is Immersion Silver suitable for RF applications?
A: Yes. Immersion Silver provides low contact resistance, excellent solderability, and no nickel barrier layer – making it ideal for RF/microwave applications.
Q7: What is the CTE compatibility of I-Tera MT40 with other materials?
A: I-Tera MT40 is thermally and dimensionally compatible with Astra MT77 and Tachyon 100G for hybrid PCB constructions. This CTE compatibility is documented and intentional .
Q8: Is I-Tera MT40 UL certified?
A: Yes. I-Tera MT40 carries UL File Number E41625 and is 94V-0 flammability rated .
Contact Us
As a specialized PCB supplier based in China, we have extensive experience with Isola I-Tera MT40, high-frequency materials, and advanced edge features (castellated holes, edge plating) .
We provide:
- Full material traceability (certificates from Isola)
- HVLP copper foil options for low-loss performance
- Castellated edge fabrication with ±0.05mm registration accuracy
- Immersion Silver / ENIG / other finishes per your requirements
- Quick-turn prototypes and volume production
- Impedance testing (TDR) with detailed reports
For technical inquiries, stack-up review, or quotation requests, please contact our sales team directly. We are ready to support your RF/microwave and high-speed digital module projects.
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