1. Product Overview
A server power backplane PCB is a critical interconnect component in server power systems. It distributes electrical energy from power supply modules to server motherboards, hard drive backplanes, and expansion cards. This board does not have onboard storage or processing power. Boards with slots are called backplanes rather than motherboards.
UGPCB offers this server power backplane PCB with the Kingboard KB6167F high-Tg lead-free laminate. The board has a 1.6mm thickness, 2 layers (double-sided), and a compact 78.26×61.3mm form factor. It meets IPC-6012 Class 2 performance requirements. The product uses Lead-Free Hot Air Solder Leveling (HASL) as the surface finish.
2. Product Classification
This server PCB falls into the following categories per IPC standards:
| Classification | Category |
|---|---|
| By Structure | Rigid Double-Sided PCB (2-layer) |
| By Application | Server Power Backplane – Computer & Peripheral Equipment |
| By Performance Class | IPC-6012 Class 2 – Dedicated Service Electronic Products |
| By Substrate | FR-4 Flame-Retardant Epoxy Glass Cloth Laminate (UL 94 V-0) |
| By Surface Finish | Lead-Free Hot Air Solder Leveling (Lead-Free HASL) |
| By Solder Mask / Legend | Green Solder Mask with White Silkscreen |
3. Key Technical Specifications
3.1 Substrate: Kingboard KB6167F High-Tg Lead-Free Laminate
KB6167F is a high-performance FR-4 laminate from Kingboard Holdings Limited. It belongs to the high-Tg lead-free epoxy copper clad laminate series.
| Parameter | Typical Value | Test Standard |
|---|---|---|
| Glass Transition Temperature (Tg) | ≥170°C (DSC method) | IPC-TM-650 |
| Thermal Decomposition Temperature (Td) | >340°C | IPC-TM-650 |
| Flammability Rating | UL 94 V-0 | UL Standard |
| Primary Specification | IPC-4101/126 | IPC-4101 |
The Tg of ≥170°C allows the material to withstand lead-free reflow soldering at peak temperatures of 260°C. Standard Tg materials (130–140°C) risk delamination during multiple reflow cycles. KB6167F also offers low Z-axis CTE and excellent CAF resistance.
3.2 Board Thickness: 1.6mm
The 1.6mm thickness provides adequate mechanical strength for connector insertion. It also enables mature, stable processing with high yield rates.
3.3 Layer Count: 2 Layers (Double-Sided)
Power backplanes focus on power distribution rather than high-speed signal routing. The 2-layer design delivers lower cost, shorter lead times, and higher reliability compared to multilayer boards.
3.4 Dimensions: 78.26 × 61.3mm
This compact size fits standard 1U or 2U server chassis spaces. UGPCB offers flexible customization for different chassis configurations.
3.5 Minimum Hole Diameter: 0.281mm
The aspect ratio determines plated through-hole reliability:
Aspect Ratio = Board Thickness / Minimum Hole Diameter = 1.6mm / 0.281mm ≈ 5.69:1
This ratio is well below the industry standard 10:1 upper limit. UGPCB applies 70 minutes of pattern plating to achieve hole copper thickness of 18–22μm. IPC-6012 Class 2 requires a minimum of 20μm on plated through-hole walls.
3.6 Line Width / Line Spacing: 0.21 × 0.186mm
The minimum line width of 0.21mm (approx. 8.3 mils) and minimum spacing of 0.186mm (approx. 7.3 mils) meet precision circuitry requirements per IPC-2221C.
3.7 Copper Foil Thickness: 1/1 OZ
Both layers have 1 ounce (approx. 35μm) copper foil. A 0.21mm-wide trace on 1OZ copper carries approximately 1.5–2A at 10°C temperature rise per IPC-2221 calculations.
3.8 Surface Finish: Lead-Free Hot Air Solder Leveling
Lead-Free HASL uses SAC305 alloy (Sn-3.0Ag-0.5Cu). Key advantages include:
- RoHS compliance
- Excellent solderability
- Extended shelf life (>12 months)
- Cost-effective for high-volume production
This finish complies with IPC-4554.
3.9 Solder Mask / Legend: Green Oil / White Character
Green solder mask provides excellent insulation and high-temperature resistance. White silkscreen ensures clear component identification for PCBA assembly and maintenance.
4. Design Considerations
4.1 Power Integrity Design
Power integrity is the primary design focus for a server power backplane PCB. Key elements include:
- Low-impedance Power Distribution Network (PDN) with large power and ground planes
- Adequate current-carrying capacity based on server power module output
- Voltage drop control from input to output ports
4.2 Thermal Management
High-current transmission generates significant heat. The design addresses this through:
- High-Tg material selection (KB6167F Tg≥170°C)
- Optimized heat dissipation paths with strategic copper layouts and thermal vias
4.3 Design for Manufacturability (DFM)
Per IPC-2221 and IPC-2222:
- Aspect ratio 5.69:1 – well below the 10:1 industry limit
- Minimum line width 0.21mm – mature etching process for 1OZ copper
- Dimensional tolerances: CNC routing ±0.15mm (6 mils), steel die punching ±0.10mm (4 mils)
5. Operating Principle
The server power backplane PCB operates through three functional layers:
Power Input Layer: Power supply modules deliver DC power (typically 12V or 48V) through input connectors.
Power Transmission Layer: Electrical energy travels through carefully designed copper traces (power and ground layers). Copper thickness (1OZ) and trace widths ensure safe temperature rise at rated currents.
Power Output Layer: Distributed power reaches output connectors that supply the server motherboard, hard drive backplanes, expansion cards, and other functional modules.
6. Applications and Use Cases
| Application | Description |
|---|---|
| Data Center Servers | Rack-mount and blade server power backplanes |
| AI Compute Servers | GPU servers and AI training cluster power distribution |
| Telecommunications | Switches and routers power backplanes |
| Industrial Controls | Industrial PCs and PLC control cabinet power modules |
This server PCB is ideal for distributing power from redundant modules to server motherboards. It also provides stable power to hard drive backplanes and expansion cards. The board enables hot-swap power and redundant switching functions.
7. Manufacturing Process
UGPCB manufactures this server power backplane PCB in full compliance with IPC-6012:
| Step | Process Description |
|---|---|
| 1. Incoming Inspection | Verify KB6167F laminate meets IPC-4101/126 |
| 2. Cutting | Cut large panels to production workboard size |
| 3. Drilling | CNC drilling of 0.281mm minimum holes |
| 4. Desmear / Electroless Copper | Chemical deposition of conductive layer; backlight test per IPC-TM-650 |
| 5. Panel Plating | Full-board copper plating |
| 6. Image Transfer | Laminate, expose, develop circuit patterns |
| 7. Pattern Plating | 70 minutes plating time; cross-section analysis verifies 18–22μm hole copper |
| 8. Etching | Remove excess copper to form final circuits |
| 9. AOI Inspection | Automated Optical Inspection scans for opens, shorts, and thin lines |
| 10. Solder Mask | Apply green solder mask with LED parallel exposure |
| 11. Legend Printing | High-precision laser legend printing for clear white characters |
| 12. Surface Finish | Lead-Free HASL per IPC-4554 |
| 13. Routing | CNC routing or steel die punching to final dimensions |
| 14. Electrical Test | High-speed flying probe test ensures electrical integrity |
| 15. FQC | Final Quality Control per IPC-6012 Class 2 acceptance criteria |
8. Performance Summary
8.1 Core Performance Advantages
- High heat resistance: KB6167F Tg≥170°C, Td>340°C – withstands 260°C lead-free reflow peak temperatures
- Precision manufacturing: 0.281mm minimum hole diameter, 0.21mm minimum line width – aspect ratio only 5.69:1
- Environmental compliance: Lead-Free HASL meets RoHS and REACH requirements
- UL safety certification: UL 94 V-0 flammability rating
- IPC standard compliance: Full IPC-4101, IPC-2221, IPC-6012 compliance
8.2 Product Features
- Double-sided routing with simple 2-layer structure
- High-reliability Kingboard KB6167F substrate
- Mature Lead-Free HASL surface finish
- Strict quality control with AOI, cross-section analysis, and flying probe testing
- Compact 78.26×61.3mm form factor for standard server chassis
9. Why Choose UGPCB?
UGPCB brings years of experience in server power backplane PCB and PCBA manufacturing:
- Full IPC process control – from material selection (KB6167F per IPC-4101/126) to final inspection (IPC-6012 Class 2)
- Precision manufacturing capability – supports minimum hole diameters of 0.2mm and minimum line widths of 3 mils (0.076mm)
- Grade A materials – Kingboard A-grade laminates, Taiyo/Guangxin brand inks
- Comprehensive quality system – AOI, cross-section analysis, flying probe testing
10. Request a Quote Today
UGPCB offers one-stop services from PCB design and engineering prototyping to volume production. Whether you need standard server power backplane PCBs or custom sizes, specialized materials, or differentiated surface finishes for your PCBA requirements, our technical team is ready to support you.
Contact UGPCB today for a quote and technical consultation!
11. Data Source Declaration
The technical standards and data cited in this article come from the following authoritative organizations:
- IPC (Association Connecting Electronics Industries): IPC-6012F Qualification and Performance Specification for Rigid Printed Boards (2023); IPC-2221C Generic Standard on Printed Board Design (2023); IPC-4101E Specification for Base Materials for Rigid and Multilayer Printed Boards; IPC-4554 Specification for Immersion Tin Plating for Printed Circuit Boards; IPC-TM-650 Test Methods Manual.
- UL (Underwriters Laboratories): UL 94 Standard for Tests for Flammability of Plastic Materials for Parts in Devices and Appliances – V-0 rating.
- Kingboard Holdings Limited: KB-6167F High-Tg Lead-Free Copper Clad Laminate product technical datasheet.
UGPCB – Your Professional Partner for Server Power Backplane PCBs.
Data in this article is sourced from publicly available technical standards and product specifications published by IPC, UL, and Kingboard Holdings Limited.
