Shengyi S1165H Halogen-Free Mid-Tg Laminate: Technical Datasheet & Guide

In the rapidly evolving landscape of high-reliability electronics, the “green” movement has shifted from a boardroom buzzword to a strict engineering requirement. As PCB engineers, we are no longer just looking for thermal stability; we are looking for it in a halogen-free package that doesn’t compromise on processability.

The Shengyi S1165H PCB material represents a strategic middle ground in the Shengyi portfolio. It’s a high-performance, halogen-free, mid-to-high Tg ($170^{\circ}C$) laminate that balances the cost-effectiveness of standard FR-4 with the thermal robustness required for modern lead-free assembly. If you’ve ever struggled with delamination during a second-side reflow on a halogen-free build, the S1165H is the material designed to solve that headache.

What Makes S1165H Different?

The “H” in S1165H signifies its halogen-free nature. Unlike traditional FR-4, which uses brominated flame retardants, the S1165H utilizes phosphorus-based chemistry and inorganic fillers. This isn’t just about environmental compliance; it fundamentally changes how the material behaves under heat.

Most mid-Tg materials sit around $150^{\circ}C$, but the Shengyi S1165H PCB material pushes into the $170^{\circ}C$ range (DSC), effectively making it a “High-Tg Halogen-Free” contender for industrial and automotive applications. It is specifically engineered to handle the $260^{\circ}C$ peak temperatures of SAC305 solder without the excessive Z-axis expansion that typically plagues cheaper “green” laminates.

Technical Specifications: The S1165H Datasheet Breakdown

When evaluating this material for a new project at <a href=”https://www.pcbsync.com/Shengyi-pcb/“>Shengyi PCB</a>, the “Big Three” metrics you need to watch are $Tg$, $Td$, and $CTE$. These define the mechanical envelope of your board.

Table 1: Thermal and Physical Properties (Typical Values)

Property	Test Method	Unit	Typical Value
Glass Transition Temp (Tg)	DSC	$^{\circ}C$	170
Decomposition Temp (Td)	TGA (5% loss)	$^{\circ}C$	360
T260 (Time to Delamination)	TMA	min	60
T288 (Time to Delamination)	TMA	min	15
Z-axis CTE (Before Tg)	TMA	ppm/$^{\circ}C$	40
Z-axis CTE (After Tg)	TMA	ppm/$^{\circ}C$	250
Total Z-Expansion (50-260°C)	TMA	%	3.2

One thing to note as an engineer: the $Td$ (Decomposition Temperature) of $360^{\circ}C$ is exceptionally high for a mid-Tg material. This tells you the resin system is extremely stable, which is vital for heavy copper boards or designs requiring manual rework where iron dwell times might be longer than expected.

Table 2: Electrical Characteristics

Property	Condition	Unit	Typical Value
Dielectric Constant (Dk)	1 MHz (C-24/23/50)	–	4.8
Dielectric Constant (Dk)	1 GHz (C-24/23/50)	–	4.5
Dissipation Factor (Df)	1 MHz (C-24/23/50)	–	0.007
Dissipation Factor (Df)	1 GHz (C-24/23/50)	–	0.010
Volume Resistivity	After Moisture	$M\Omega-cm$	$2.0 \times 10^8$
Water Absorption	D-24/23	%	0.15

With a $Df$ of $0.010$ at 1 GHz, the S1165H is not a dedicated high-speed/low-loss material like the S7439, but it is more than adequate for high-reliability instrumentation, server motherboards, and automotive ECUs where frequency is moderate but reliability is non-negotiable.

Engineering Guide: Designing for S1165H

Transitioning to a Shengyi S1165H PCB material requires some adjustments in your design rules and communication with your fabricator.

1. Through-Hole Reliability and Z-CTE

The S1165H has a Z-axis CTE of $40 ppm/^{\circ}C$ below $Tg$. While this is higher than ultra-high-Tg materials like S1000-2M, the total expansion of $3.2\%$ is still within the safe zone for 8 to 12-layer boards. If you are moving beyond 14 layers with small vias (aspect ratios $>1:10$), you should perform a thermal stress simulation to ensure the copper barrel can handle the strain.

2. CAF (Conductive Anodic Filament) Resistance

Halogen-free materials can sometimes be more prone to CAF because of the interface between the inorganic fillers and the glass fibers. However, Shengyi has optimized the S1165H with an “Excellent Anti-CAF” resin system. It is suitable for designs with hole-to-hole spacings as low as $0.65mm$, provided your fabricator uses the correct desmear and drilling parameters.

3. UV Blocking and AOI Compatibility

S1165H comes standard with UV-blocking properties. This is critical for modern fabrication lines that use Automated Optical Inspection (AOI). Without UV blocking, the AOI laser can penetrate the laminate, leading to false “short” or “open” detections. This makes S1165H a very “fab-friendly” material.

Fabrication and Processing Tips

If you’re overseeing the manufacturing of boards using S1165H, you need to ensure the press cycle and drilling parameters are dialed in. Halogen-free resins are physically “harder” than standard FR-4.

Drilling: Reduce your hit count by roughly $15-20\%$ compared to standard S1141. The inorganic fillers in S1165H act as an abrasive, which can dull drill bits faster, leading to “nail-heading” or rough hole walls if not managed.

Lamination Press Cycle:

Heat-up Rate: $1.5 \text{ to } 2.5^{\circ}C/min$ (between $80^{\circ}C$ and $140^{\circ}C$).

Curing Temperature: $185 \text{ to } 195^{\circ}C$.

Curing Time: Minimum 60 minutes.

Desmear: Permanganate desmear is generally sufficient, but for high-reliability builds, a plasma desmear step ensures that any “filled” resin smear is completely removed from the inner layer copper.

Top Applications for S1165H Halogen-Free Laminate

Due to its balance of thermal stability and environmental compliance, the S1165H is the “Goldilocks” material for several industries:

Automotive Electronics: Sensors, lighting controls, and dashboard electronics that require halogen-free status for EU markets.

Communication Equipment: Network switches and base stations that experience significant internal heat but don’t require “Ultra-Low Loss” performance.

Industrial Instrumentation: Power supplies and controllers used in 24/7 factory environments where $Tg$ $170^{\circ}C$ provides a necessary safety buffer.

Consumer Computing: High-end laptops and gaming consoles where “green” branding is a key selling point.

Essential Resources and Downloads

For the nitty-gritty details, always refer to the official documentation:

Official S1165H Datasheet (PDF): Download Link via Shengyi – Note: S1165 and S1165H often share data sheets depending on regional distribution.

Shengyi Technology USA Portal: Laminate Database – Great for comparing S1165H against S1150G or S1170G.

IPC-4101E Specification: Reference sheet /94 or /95 for Halogen-Free High-Tg requirements.

UL Certification E109769: Search the UL Product iQ database to verify flammability and MOT ratings for S1165H.

Frequently Asked Questions (FAQs)

1. Is S1165H a direct replacement for S1141?

Not exactly. S1165H is Halogen-Free and has a higher $Tg$ ($170^{\circ}C$ vs $140^{\circ}C$). It is an upgrade. If you are currently using S1141 and need to go “Green” or improve thermal reliability, S1165H is the logical next step.

2. What is the shelf life of S1165H Prepreg?

At room temperature ($<23^{\circ}C$ and $<50\%$ RH), it is typically 3 months. In cold storage ($<5^{\circ}C$), it lasts 6 months. Always normalize the material for at least 4 hours before opening the moisture-proof bag to prevent condensation.

3. Can I use S1165H for boards with more than 12 layers?

Yes, but with caution. For high-layer count boards ($>12$ layers), the $3.2\%$ Z-axis expansion becomes more significant. For 16+ layers, I usually recommend stepping up to the S1000-2H or S1000-2M series, which offer even lower CTE.

4. Does S1165H emit toxic gases during soldering?

No. Because it is halogen-free, it does not release toxic halogenated gases (like dioxins) during high-temperature reflow or if the board were to catch fire, which is a major safety requirement in confined spaces like subways or aviation.

5. What is the standard copper weight for S1165H?

It supports standard copper from 1/3 oz up to 3 oz. For anything over 3 oz, you should consult with your <a href=”https://www.pcbsync.com/Shengyi-pcb/“>Shengyi PCB</a> partner to ensure the prepreg resin content is high enough to fill the large copper gaps.

Final Thoughts for Designers

The Shengyi S1165H PCB material is a reliable, “workhorse” laminate for the modern, environmentally conscious engineer. It provides the thermal stability of a high-Tg material with the safety of a halogen-free resin system. If your project needs to meet RoHS/REACH standards without breaking the bank on “ultra-premium” materials, S1165H is likely your best candidate.