DS-7402 PCB laminate full guide — specs (Tg 165°C, Td 380°C, Dk 3.91), CAF resistance, halogen-free compliance, variant comparison, applications, and 5 engineer FAQs. Datasheet resources included.

If you’re designing a PCB that needs to survive lead-free assembly, handle real-world operating temperatures, and still comply with RoHS and halogen-free environmental requirements — all without the cost premium of exotic laminates — DS-7402 PCB laminate from Doosan Electro-Materials is one of the more credible options in the middle-Tg halogen-free category. This guide pulls together the full spec picture, application context, and processing considerations that engineers actually need when evaluating this material.

What Is DS-7402 PCB Laminate?

DS-7402 is a middle glass transition temperature (Tg) copper clad laminate (CCL) manufactured by Doosan PCB materials — a South Korean supplier with a well-established presence in the Asian PCB supply chain. The material is built on a modified epoxy resin system reinforced with woven E-glass and is completely free of halogens, antimony, and red phosphorus. That last point matters: many so-called “halogen-free” materials in this Tg class still rely on antimony trioxide as a synergist in their flame retardant system. DS-7402 avoids this.

The defining characteristic of DS-7402 is its combination of a 165°C Tg with a remarkably high decomposition temperature (Td) of 380°C — that’s unusually good for a mid-Tg product and gives significant headroom for lead-free reflow processes. Add in excellent CAF (Conductive Anodic Filament) resistance and tight dimensional control, and you have a material positioned squarely at mobile devices, consumer electronics, automotive ECUs, and high-layer-count HDI boards.

DS-7402 PCB Laminate: Complete Technical Specifications

Thermal Properties

Property	Value	Test Method
Glass Transition Temperature (Tg)	165°C	TMA / DSC
Decomposition Temperature (Td)	380°C (5% weight loss)	TGA
T-288 (Time to Delamination)	> 15 min	IPC-TM-650 2.4.24.1
CTE X-axis (below Tg)	15 ppm/°C	TMA
CTE Y-axis (below Tg)	14 ppm/°C	TMA
CTE Z-axis α1 (below Tg)	38 ppm/°C	TMA
CTE Z-axis α2 (above Tg)	230 ppm/°C	TMA
Thermal Conductivity	0.45 W/m·K	—
Max Operating Temperature (UL 796)	130°C	—

The Td of 380°C is the headline figure for this material. Most mid-Tg halogen-free laminates land in the 330–350°C range — getting 380°C puts DS-7402 closer to high-Tg territory in terms of thermal decomposition stability, even though its Tg sits at 165°C. This is particularly valuable for boards going through multiple lead-free reflow passes.

Electrical Properties

Property	Value	Frequency / Condition
Dielectric Constant (Dk)	3.91	1 GHz
Dissipation Factor (Df)	0.014	1 GHz
Volume Resistivity	≥ 10⁸ MΩ·cm	C-96/35/90
Surface Resistivity	≥ 10⁶ MΩ	C-96/35/90
CTI (Comparative Tracking Index)	≥ 600 V	—

A Dk of 3.91 at 1 GHz is worth noting — it’s notably lower than standard FR-4 which typically runs 4.5–5.0 in the same frequency band. This makes DS-7402 more signal-friendly for DDR memory interfaces, moderate-speed SerDes, and mixed-signal boards that need better impedance control without jumping to a premium low-loss material. The Df of 0.014 is acceptable for digital designs up to a few GHz.

Mechanical Properties

Property	Value	Standard
Flexural Strength	450–550 MPa	IPC-TM-650 2.4.4
Peel Strength (1 oz Cu)	1.15 kgf/cm	IPC-TM-650 2.4.8
Water Absorption	0.26%	D-24/23

Compliance & Certification

Attribute	Status
Halogen-Free	Yes (Cl < 900 ppm, Br < 900 ppm)
Antimony-Free	Yes
Red Phosphorus-Free	Yes
RoHS Compliance	Yes
UL Flammability Rating	94 V-0
CAF Resistance	Yes

DS-7402 Variant Family: Understanding the Suffix System

Doosan offers several variants under the DS-7402 platform, each tuned for slightly different requirements. Knowing the difference prevents you from speccing the wrong grade:

Variant	Key Differentiator	Target Application
DS-7402	Baseline mid-Tg halogen-free	Consumer electronics, mobile, A/V
DS-7402M	Improved moisture resistance, same Td ~370°C	Similar to base, enhanced humidity environments
DS-7402H	Higher Tg (~170°C) version of the 7402 platform	Lead-free automotive, networking
DS-7402LC	Low CTE version, optimized warpage control	SLP smartphones, eSSD, interposer boards

For smartphone SLP (Substrate-Like PCB) applications, DS-7402LC is the correct call — it trades slightly different resin characteristics for superior warpage control in ultra-thin stackups. If you’re just building a 6-layer consumer electronics motherboard, the base DS-7402 is the right starting point.

Where DS-7402 PCB Laminate Gets Specified: Real Use Cases

Mobile Devices and Smart Consumer Electronics

This is the bread-and-butter application for DS-7402. The low Dk relative to standard FR-4 reduces parasitic capacitance at high-speed signal layers. CAF resistance is particularly valuable in high-density smartphone PCBs where via-to-via spacing is extremely tight — CAF failures are a known reliability concern in fine-pitch HDI boards.

Automotive ECU, DCU, and TCU Boards

Doosan explicitly positions DS-7402 for automotive ECU (Engine Control Unit), DCU (Domain Control Unit), and TCU (Transmission Control Unit) applications. The combination of halogen-free compliance with IMDS-traceable chemistry, CAF resistance, and good thermal stability at 165°C Tg makes it viable for under-hood and near-powertrain placements where operating temperatures are moderate but the environment is thermally and electrically hostile.

Notebook Computers and A/V Equipment

High-layer-count notebook motherboards benefit from DS-7402’s good thickness control — critical for maintaining via registration and impedance accuracy in boards with 12 to 20+ layers. A/V devices, set-top boxes, and streaming hardware running continuous duty cycles also fit well here.

Memory Modules and SSD Drives

For this application specifically, DS-7402LC is the preferred sub-variant. Low Z-axis CTE reduces solder joint fatigue during thermal cycling, which is a real failure mode in BGA-heavy memory module and SSD controller board designs.

DS-7402 vs. Competing Mid-Tg Halogen-Free Laminates

Material	Supplier	Tg (°C)	Td (°C)	Dk @ 1 GHz	Halogen-Free	Antimony-Free
DS-7402	Doosan	165	380	3.91	Yes	Yes
S1000-2M	Shengyi	170	≥ 350	4.2	Yes	Yes
TU-862 HF	Taiwan Union	160	≥ 340	4.3	Yes	Yes
IT-158Q	Iteq	160	≥ 360	4.0	Yes	Yes
NP-175F	Nanya	170	≥ 350	4.3	Yes	Yes

DS-7402 stands out primarily for its Td of 380°C — the highest in this comparison group — and its relatively low Dk of 3.91 which gives it an edge in signal-integrity-sensitive designs. The tradeoff is that the baseline Tg of 165°C is slightly lower than S1000-2M or NP-175F. For applications where Tg headroom is the top priority, DS-7402H bumps that up to ~170°C while staying within the Doosan material family.

Processing Notes for Fabricators

Lamination: DS-7402 processes with standard multilayer lamination cycles. The resin system is compatible with conventional press programs. Doosan specifically highlights good thickness control as a product strength — fabricators running tight HDI tolerances should find this consistent batch-to-batch.

Lead-Free Reflow Compatibility: The T-288 > 15 min rating and Td of 380°C mean DS-7402 handles multiple SAC305 reflow passes without issue. For boards going through three or more reflow cycles (both sides plus rework allowance), this thermal margin is genuinely useful.

CAF Prevention: DS-7402’s built-in CAF resistance reduces the risk of electrochemical migration between adjacent vias under DC bias at elevated temperature and humidity. This matters in HDI designs where engineers are pushing drill-to-copper spacing to the limit. That said, laminate CAF resistance should still be combined with proper PCB design rules (minimum via spacing, surface finish selection) rather than relied upon as a single-point fix.

Drill Parameters: Standard carbide drill geometry. No special adjustments needed for the base glass fiber system. Fine-drill work below 0.15 mm should still use appropriate entry material to control hole quality.

Storage: Keep panels in original packaging in a dry, temperature-controlled environment. Bake at 120°C for 2–4 hours before lamination if panels have been exposed to elevated humidity or stored beyond 6 months.

Useful Resources for DS-7402 PCB Laminate

• Doosan Electro-Materials Product Page — Official DS-7402 product listing with RoHS and MSDS download links (doosanelectromaterials.com)
• IPC-4101E Standard — The governing specification for rigid PCB base materials; DS-7402 aligns with halogen-free FR-4 slash sheets
• IPC-TM-650 Test Methods — Defines how Tg, Td, CTE, peel strength, and delamination times are measured and reported
• UL Product iQ (iq.ul.com) — Verify current UL 94 V-0 certification status and applicable copper foil weights
• MCL PCB DS-7402 Datasheet — Millennium Circuits Limited hosts a PDF datasheet version: mclpcb.com
• RayPCB Doosan PCB Materials Guide — Doosan PCB material application guide covering the full DS-7402 product family
• IPC-2221B — Generic PCB design standard; useful for matching material class to environmental and performance requirements

5 FAQs About DS-7402 PCB Laminate

Q1: Is DS-7402 a direct replacement for standard FR-4 in existing designs?

For most multilayer consumer electronics designs — yes, with essentially the same processing conditions. Doosan specifically engineered the DS-7402 family to maintain FR-4 compatibility in drilling, lamination, and chemical processing. The real change is moving from a halogenated to a phosphorus/antimony-free flame retardant system, which doesn’t affect fabrication workflow but does require material qualification sign-off in regulated industries like automotive.

Q2: What’s the difference between DS-7402 and DS-7409?

The DS-7409 targets higher Tg applications (Tg ≥ 170°C) and is positioned more toward high-reliability automotive and telecom infrastructure boards where maximum thermal robustness is the priority. DS-7402 sits at 165°C Tg but achieves a higher Td (380°C vs. ~340°C), making it better suited to fine-pitch HDI consumer designs where decomposition resistance and CAF resistance matter more than maximum Tg headroom.

Q3: Can DS-7402 pass REACH and EU environmental regulations?

Yes. Being halogen-free (Cl < 900 ppm, Br < 900 ppm), antimony-free, and red phosphorus-free positions DS-7402 well against REACH SVHC restrictions and the EU’s RoHS Directive. That said, for EU-facing products, always verify with your laminate distributor that the current production batch holds current RoHS certification documentation — regulations update and certificate expiry dates matter.

Q4: What is CAF resistance and why does it matter for DS-7402?

CAF (Conductive Anodic Filament) is an electrochemical failure mode where copper ions migrate along glass fiber–resin interfaces between adjacent vias or conductors under DC voltage and humidity. In high-density HDI boards with tight via spacing, CAF is a known long-term reliability failure mode. DS-7402’s resin system includes improved adhesion at the fiber–resin interface, which blocks the migration path. This is one of the reasons Doosan markets this material specifically for mobile and fine-pitch HDI applications.

Q5: Is there a minimum order quantity, and where can DS-7402 be sourced outside Asia?

DS-7402 is available through Doosan’s authorized distributor network globally, including through fabricators who carry Doosan materials in their approved vendor lists. Availability outside Asia can vary — it’s worth confirming with your PCB fabricator whether they stock this specific laminate or can qualify it into their supply chain. For prototype quantities, fabricators who already carry Doosan materials will often have standard panel sizes available without special minimums.

Final Thoughts

DS-7402 PCB laminate occupies a well-defined space: it’s the halogen-free, mid-Tg workhorse that covers the bulk of consumer electronics, mobile, and moderate-duty automotive PCB applications without the material cost of high-Tg or low-loss grades. Its standout spec — that Td of 380°C combined with CAF resistance — makes it genuinely well-suited to HDI boards running lead-free assembly, where thermal decomposition margin and long-term reliability in fine-pitch via structures are real engineering concerns, not just spec sheet talking points.

If your application sits in the automotive or high-reliability networking space, look at DS-7402H or DS-7409 for higher Tg. If you’re building ultra-thin smartphone or SSD interposer boards with severe warpage requirements, DS-7402LC is the right variant. For everything in between — which covers a large portion of the PCB volume built today — the base DS-7402 is a solid, proven choice.

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