Active Member
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[China]
Address: 6-11C Shidai Jingyuan Fuyong Town, Baoan District, Shenzhen City, Guangdong Province, China
Contact name:Sally Mao
Shenzhen Bicheng Electronics Technology Co., Ltd |
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High Tg Printed Circuit Board (PCB) Built on 1.6mm TU-872 SLK Sp (Low DK FR-4) With Immersion Gold
(Printed Circuit Boards are custom-made products, the picture and parameters shown are just for reference)
Brief Introduction
This is a type of low DK/DF FR-4 PCB which is built on TU-872 SLK Sp material. It is made on 4 layers copper with 1oz each layer, coating immersion gold and green solder mask. Final finished thickness is 1.6mm +/- 10%. A panel consists of 16 pieces.
Applications
1. Radio Frequency
2. Backpanel, High performance computing
3. Line cards, Storage
4. Servers, Telecom, Base station
5. Office Routers
PCB Specifications
| Item | Description | Requirement | Actual | Result |
| 1. Laminate | Material Type | FR-4 TU-872 SLK Sp | FR-4 TU-872 SLK Sp | ACC |
| Tg | 170℃ | 170℃ | ACC | |
| Supplier | TU | TU | ACC | |
| Thickness | 1.6±10% mm | 1.61-1.62mm | ACC | |
| 2.Plating thickness | Hole Wall | ≥25µm | 26.51µm | ACC |
| Outer copper | 35µm | 40.21µm | ACC | |
| Inner Copper | 30µm | 31.15µm | ACC | |
| 3.Solder mask | Material Type | Kuangshun | Kuangshun | ACC |
| Color | Green | Green | ACC | |
| Rigidity (Pencil Test) | ≥4H or above | 5H | ACC | |
| S/M Thickness | ≥10 µm | 19.55µm | ACC | |
| Location | Both Sides | Both Sides | ACC | |
| 4. Component Mark | Material Type | TAIYO/ IJR-4000 MW300 | IJR-4000 MW300 | ACC |
| Color | White | White | ACC | |
| Location | C/S, S/S | C/S, S/S | ACC | |
| 5. Peelable Solder Mask | Material Type | |||
| Thickness | ||||
| Location | ||||
| 6. Identification | UL Mark | YES | YES | ACC |
| Date Code | WWYY | 0421 | ACC | |
| Mark Location | Solder Side | Solder Side | ACC | |
| 7. Surface Finish | Method | Immersion Gold | Immersion Gold | ACC |
| Tin Thickness | ||||
| Nickel Thickness | 3-6µm | 5.27µm | ACC | |
| Gold Thickness | 0.05µm | 0.065µm | ACC | |
| 8. Normativeness | RoHS | Directive 2015/863/EU | OK | ACC |
| REACH | Directive 1907 /2006 | OK | ACC | |
| 9.Annular Ring | Min. Line Width (mil) | 7mil | 6.8mil | ACC |
| Min. Spacing (mil) | 6mil | 6.2mil | ACC | |
| 10.V-groove | Angle | 30±5º | 30º | ACC |
| Residual thickness | 0.4±0.1mm | 0.38mm | ACC | |
| 11. Beveling | Angle | |||
| Height | ||||
| 12. Function | Electrical Test | 100% PASS | 100% PASS | ACC |
| 13. Appearance | IPC Class Level | IPC-A-600J &6012D Class 2 | IPC-A-600J &6012D Class 2 | ACC |
| Visual Inspection | IPC-A-600J &6012D Class 2 | IPC-A-600J &6012D Class 2 | ACC | |
| Warp and Twist | ≦0.7% | 0.32% | ACC | |
| 14. Reliability Test | Tape Test | No Peeling | OK | ACC |
| Solvent Test | No Peeling | OK | ACC | |
| Solderability Test | 265 ±5℃ | OK | ACC | |
| Thermal Stress Test | 288 ±5℃ | OK | ACC | |
| Ionic Contamination Test | ≦ 1.56 µg/c㎡ | 0.58µg/c㎡ | ACC |
High Tg PCB
The thermal properties of the resin system are characterized by the glass transition temperature (Tg), which always is expressed in °C. The most commonly used property is the thermal expansion. When measuring the expansion versus the temperature, we can get a curve as shown in following picture. The Tg is determined by the intersection of the tangents of the flat and steep parts of the expansion curve. Below the glass transition temperature, the epoxy resin is rigid and glassy. When the glass transition temperature is exceeded, it changes to a soft and rubbery state.
For the most commonly used types of epoxy resin (FR-4 grade), the glass transition temperature is in the range 115-130°C, so when the board is soldered, the glass transition temperature is easily exceeded. The board expands in the Z-axis direction and stresses the copper of the hole wall. The expansion of epoxy resin is about 15 to 20 times greater than that of copper when exceeding Tg. This implies a certain risk of wall cracking in plated-through holes, and the more resin around the hole wall, the greater risk. Below the glass transition temperature, the expansion ratio between epoxy and copper is only three times, so here the risk of cracking is negligible.
The Tg of general board is above 130 celsius degrees, high Tg is generally greater than 170 celsius degrees, medium Tg is about greater than 150 celsius degrees.
PCB boards with Tg ≥ 170 ° C are usually called high Tg PCBs.
Partial High Tg Material in House
| Material | Tg (℃) | Manufacturer |
| S1000-2M | 180 | Shengyi |
| TU-768 | 170 | TU |
| TU-872 SLK Sp | 170 | TU |
| TU-883 | 170 | TU |
| IT-180ATC | 175 | ITEQ |
| KB-6167F | 170 | KB |
| M6 | 185 | Panasonic |
| Kappa 438 | 280 | Rogers |
| RO4350B | 280 | Rogers |
| RO4003C | 280 | Rogers |
| RO4730G3 | 280 | Rogers |
| RO4360G2 | 280 | Rogers |
