Multilayer Printed Circuit Board 8-Layer PCBs Built On Tg175℃ FR-4 With Immersion Gold

Multilayer Printed Circuit Board 8-Layer PCBs Built On Tg175℃ FR-4 With Immersion Gold

(Printed circuits boards are custom-made products, the picture and parameters shown are just for reference)

1.1 General description

It's 1.6 mm thick with white silkscreen(Taiyo) on green solder mask (Taiyo) and immersion gold on pads. The base material is from Taiwan ITEQ supplying 1 up PCB per panel. They're fabricated per IPC 6012 Class 2 using supplied Gerber data. Each 25 panels are packed for shipment.

1.2 Features and benefits

1. High Tg Materials are RoHS compliant and suitable for high thermal reliability needs;

2. Immersin gold has high solderability, no stressing of circuit boards and less contamination of PCB surface;

3. Delivery on time. Higher than 98% on-time-delivery rate;

4. 30000㎡output capability per month;

5. More than 18 years of experience;

6. Powerful PCB capabilities support your research and development, sales and marketing;

7. Any Layer HDI PCBs;

8. International approvals;

1.3 PCB Specifications

1.4 Applications

WiFi Range Extender

CCTV System

Satellite Communication

5G Speed

Router WiFi 4G

Solar Panel Inverter

GPS Tracking Systems

Embedded Processor

PLC Programs

Phone systems

1.5 Glass Transition Temperature (Tg)

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.   

1.6 Manufacturing Process of Multi-layer PTH PCB (via filled)

(1). Material Shearing                            

(2). Inner Layer Dry Film                                                                  

(3). Inner Layer Etching                                                                   

(4). AOI 1                                                                        

(5). Black Oxidation                                                                         

(6). Milling Outline Frame                                                                

(7). Inner Layer Drilling                                        

(8). PTH 1

(9). Inner Layer Dry Film

(10). Pattern Plating 1

(11). Via filled

(12). Outer Layer Drilling

(13). PTH 2

(14). Pattern Plating 2

(15). Outer Layer Dry Film

(16). Copper-tin Electro-Plating

(17). Peeling and Etching

(18). AOI 2

(19). Solder Mask

(20). Silkscreen Printing

(21). Surface Finishing

(22). Electrical Testing

(23). Prolie Contouring

(24). FQC

(25). Packaging

(26). Delivery

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