PI-515G and PI-520G represent the highest thermal performance tier in Kingboard's laminate portfolio. Despite their "PI" prefix suggesting polyimide, these materials share the IPC-4101E/127/128/130 halogen-free slash sheets with the HF-170 family and are classified as ultra-high-Tg halogen-free laminates rather than traditional polyimide substrates. PI-520G delivers a verified Tg of 204°C (DSC), Td of 412°C, and Z-CTE of just 1.9% (50–260°C)—making it the most thermally capable material in Kingboard's entire product range.
The critical positioning: when HF-170 (Tg 180°C) is not enough and traditional polyimide (Tg >250°C, 5–10× cost) is excessive, PI-515G and PI-520G fill the gap with Tg 200°C+ performance at a fraction of polyimide cost, while maintaining halogen-free compliance and anti-CAF capability. This makes them ideal for the most demanding server, backplane, wireless infrastructure, and automotive applications where every degree of thermal margin matters.
In This Guide
- Where PI-515G and PI-520G Fit in Kingboard's Thermal Performance Range
- PI-520G Verified Datasheet Specifications from Official Kingboard PDF
- PI-515G Estimated Specifications and Comparison with PI-520G
- Thermal Endurance Analysis: Why Td 412°C and T-288 >60 min Matter
- PI-520G vs HF-170 vs KB-6167F: High-Tg Material Comparison
- Z-Axis CTE 1.9%: Impact on Via Reliability in High-Layer-Count Boards
- Target Applications: Servers, Backplanes, and Extreme Reliability Electronics
- Manufacturing Process Considerations for Ultra-High-Tg Materials
- How to Order PI-515G and PI-520G PCBs from APTPCB
Where PI-515G and PI-520G Fit in Kingboard's Thermal Performance Range
Kingboard's thermal Tg hierarchy: KB-6150/6160 (132–135°C) → KB-6164 (140°C) → HF-140 (141°C) → KB-6165/6165F (153–157°C) → KB-6167F (175°C) → HF-170 (180°C) → PI-515G (~190°C est.) → PI-520G (204°C). The PI series provides the highest Tg in the entire Kingboard portfolio—24°C above HF-170 and 29°C above KB-6167F.
PI-520G Verified Datasheet Specifications from Official Kingboard PDF
All values sourced from Kingboard's official PI-520G product datasheet (kblaminates.com). Specimen thickness: 1.6 mm (8×7628). IPC-4101E/127/128/130 ✓. UL: E115974 ✓
Thermal Properties
| Test Item | Test Method | Condition | Typical Value ✓ |
|---|---|---|---|
| Thermal Stress | 2.4.13.1 | Float 288°C, Unetched | ≥240 sec |
| Glass Transition (Tg, DSC) | 2.4.25 | DSC | 204°C |
| Glass Transition (Tg, DMA) | 2.4.24.4 | DMA | 215°C |
| Z-axis CTE Alpha 1 | 2.4.24 | TMA | 36 ppm/°C |
| Z-axis CTE Alpha 2 | 2.4.24 | TMA | 210 ppm/°C |
| Z-axis Expansion (50–260°C) | 2.4.24 | TMA | 1.9% |
| X/Y CTE (40–125°C) | 2.4.24 | TMA | 12/15 ppm/°C |
| T-260 | 2.4.24.1 | TMA | >60 min |
| T-288 | 2.4.24.1 | TMA | >60 min |
| Td (5% weight loss) | 2.4.24.6 | TGA | 412°C |
| Flammability | UL94 | E-24/125 | V-0 |
Electrical Properties
| Test Item | Test Method | Condition | Typical Value ✓ |
|---|---|---|---|
| Surface Resistivity | 2.5.17.1 | C-96/35/90 | 5.0×10⁸ MΩ |
| Volume Resistivity | 2.5.17.1 | C-96/35/90 | 6.2×10⁹ MΩ·cm |
| Dielectric Breakdown | 2.5.6 | D-48/50+D-0.5/23 | ≥45 kV |
| Dk @1 GHz | IEC 61189-2-721 | Etched, R/C 50% | 4.6 |
| Dk @10 GHz | IEC 61189-2-721 | Etched, R/C 50% | 4.5 |
| Df @1 GHz | IEC 61189-2-721 | Etched, R/C 50% | 0.011 |
| Df @10 GHz | IEC 61189-2-721 | Etched, R/C 50% | 0.013 |
| CTI | IEC 60112 | Etched, 0.1% NH₄Cl | ≥200V |
| Arc Resistance | 2.5.1 | D-48/50+D-0.5/23 | 124 sec |
Mechanical Properties
| Test Item | Test Method | Condition | Typical Value ✓ |
|---|---|---|---|
| Peel Strength (1 oz) | 2.4.8 | Float 288°C/10 sec | 1.30 N/mm |
| Flexural Strength (MD) | 2.4.4 | — | 600 N/mm² |
| Flexural Strength (XD) | 2.4.4 | — | 530 N/mm² |
| Moisture Absorption | 2.6.2.1 | D-24/23 | 0.10% |
Key Features (from official datasheet)
- Halogen-free: No bromine, antimony, or red phosphorus (IEC 61249-2-21)
- Anti-CAF capability: Electrochemical migration resistance for high-voltage reliability
- UL File: E115974 (note: different from the E123995 used by most other Kingboard FR-4 products)
PI-515G Estimated Specifications and Comparison with PI-520G
No official PI-515G datasheet PDF has been independently verified. Values are estimated from product naming convention and PI-520G reference data:
| Property | PI-515G (Estimated) | PI-520G (Verified ✓) |
|---|---|---|
| Tg (DSC) | ~190°C | 204°C |
| Tg (DMA) | ~200°C | 215°C |
| Td (TGA) | ~400°C | 412°C |
| Z-CTE Alpha 1 | ~38 ppm/°C | 36 ppm/°C |
| Z-CTE (50–260°C) | ~2.1% | 1.9% |
| T-260 / T-288 | >60 min | >60 min |
| Dk @1 GHz | ~4.6 | 4.6 |
| Df @1 GHz | ~0.012 | 0.011 |
| Halogen-Free | Yes (est.) | Yes ✓ |
| Anti-CAF | Yes (est.) | Yes ✓ |
| Cost vs KB-6167F | ~1.3–1.5× | ~1.5–2.0× |
Data Confidence Note: PI-515G values are estimates. Request official datasheet from Kingboard or APTPCB for production qualification.
Thermal Endurance Analysis: Why Td 412°C and T-288 >60 min Matter
PI-520G's Td of 412°C sets it apart from every other material in Kingboard's portfolio:
| Material | Td (°C) ✓ | Margin Above 260°C | Margin Above 288°C |
|---|---|---|---|
| KB-6160 | 305 | 45°C | 17°C |
| KB-6165 | 339 | 79°C | 51°C |
| KB-6167F | 349 | 89°C | 61°C |
| HF-170 | 385 | 125°C | 97°C |
| PI-520G | 412 | 152°C | 124°C |
The T-288 >60 min means PI-520G can withstand continuous 288°C exposure for over an hour without delamination. For boards requiring multiple BGA rework cycles at 288°C peak, PI-520G provides the largest thermal safety margin available in Kingboard's portfolio.
PI-520G vs HF-170 vs KB-6167F: High-Tg Material Comparison
| Property | KB-6167F ✓ | HF-170 ✓ | PI-520G ✓ |
|---|---|---|---|
| Tg (DSC) | 175°C | 180°C | 204°C |
| Tg (DMA) | — | 190°C | 215°C |
| Td (TGA) | 349°C | 385°C | 412°C |
| Z-CTE (50–260°C) | 2.6% | 2.2% | 1.9% |
| Z-CTE Alpha 1 | 40 ppm/°C | 45 ppm/°C | 36 ppm/°C |
| T-288 | >35 min | >60 min | >60 min |
| Dk @1 GHz | 4.6 | 4.6 | 4.6 |
| Df @1 GHz | 0.016 | 0.011 | 0.011 |
| Anti-CAF | Yes | Yes | Yes |
| Halogen-Free | No | Yes | Yes |
| UL File | E123995 | E115974 ✓ | E115974 |
PI-520G and HF-170 share the same IPC slash sheets (/127/128/130), the same Dk/Df profile, and the same halogen-free/anti-CAF features. PI-520G is essentially an enhanced version of HF-170 with 24°C higher Tg and 27°C higher Td.
Z-Axis CTE 1.9%: Impact on Via Reliability in High-Layer-Count Boards
The Z-CTE 50–260°C of 1.9% is the lowest value in Kingboard's halogen-free product range. For high-layer-count boards (16+ layers) with thick stackups (>3.0 mm), via barrel fatigue is the primary failure mechanism during thermal cycling.
Via stress comparison for a 3.2 mm board during 260°C reflow:
| Material | Z-CTE 50-260°C | Z-Expansion (3.2mm) | Relative Stress |
|---|---|---|---|
| KB-6167F | 2.6% | 83 µm | 1.37× |
| HF-170 | 2.2% | 70 µm | 1.16× |
| PI-520G | 1.9% | 61 µm | 1.00× |
The 22 µm reduction versus KB-6167F directly translates to longer via fatigue life, particularly relevant for equipment with 15–20 year service life requirements.
Target Applications: Servers, Backplanes, and Extreme Reliability Electronics
High-End Servers: Next-generation server boards where high layer count (20+ layers), high via density, and halogen-free compliance require thermal margins beyond HF-170.
Backplanes: High-complexity backplanes for telecom switches, data center routers, and storage systems where 20+ year reliability under continuous thermal cycling is required.
Wireless Communication Infrastructure: Base station equipment and network infrastructure where telecom-grade halogen-free compliance is mandatory.
Automotive Electronics (High-Voltage): EV power management, BMS, and ADAS computing modules where operating temperatures approach 150°C. Automotive PCB capabilities include PI-520G processing.
Industrial Control Systems: Process controllers, motor drives, and power conversion in elevated ambient temperatures.
Defense and Aerospace: While not traditional MIL-spec polyimide (Tg >250°C DSC), the 204°C Tg and exceptional thermal endurance may satisfy many military applications requiring halogen-free compliance.
Manufacturing Process Considerations for Ultra-High-Tg Materials
PI-520G's ultra-high Tg requires adjusted lamination parameters. Expect cure temperatures >200°C (versus >190°C for KB-6167F). Contact Kingboard or APTPCB for the PP-PI520G processing guide with specific parameters.
Drilling: Dense resin system may increase drill wear. Reduced hit counts and optimized feed/speed recommended.
Copper adhesion: Peel strength 1.30 N/mm (float 288°C) meets IPC requirements but is lower than standard FR-4 (KB-6160: 1.75 N/mm). Design with adequate copper feature sizes.
Moisture sensitivity: Water absorption 0.10% is excellent. Pre-bake before lamination recommended for material stored beyond shelf life.
All standard surface finishes compatible. ENIG recommended for maximum reliability in high-layer-count applications.
How to Order PI-515G and PI-520G PCBs from APTPCB
Submit your design files specifying PI-515G or PI-520G. Our engineering team reviews thermal environment, layer count, and halogen-free needs to confirm suitability—and may recommend HF-170 if PI-520G's additional cost is not justified. For complete fabrication and assembly, we provide integrated quotes with quality documentation including halogen-free compliance certificates.