PCB News - Quality detection method for electroplating prepreg of circuit board

Quality detection method for electroplating prepreg of circuit board

Pre-impregnated material is a kind of sheet material composed of resin and carrier. The resin is in the B-stage, under the action of temperature and pressure, it has fluidity and can quickly cure and complete the bonding process, and forms an insulating layer together with the carrier. Commonly known as prepreg or bonding film. In order to ensure the high reliability and quality stability of the multilayer printed circuit board, the quality of the semi-solid film must be tested (trial lamination method). The characteristics of the circuit board electroplating prepreg include the characteristics before lamination and the characteristics after lamination. The characteristics before lamination mainly refer to: resin content%, fluidity%, volatile content% and gel time (S). The characteristics after lamination refer to: electrical properties, thermal shock properties and flammability. For this reason, in order to ensure the high reliability of the multilayer printed circuit board and the stability of the lamination process parameters, it is very important to detect the characteristics of the electroplating prepreg of the circuit board before lamination.
1. Determination of resin content (%) of circuit board:
(1) Preparation of test piece: According to the fiber direction of the circuit board electroplating prepreg: cut into 100*100 (mm) small test pieces at a 45° angle;
(2) Weighing: Weigh Wl (grams) using a balance with an accuracy of 0.001 grams;
(3) Heating: heating and burning at a temperature of 566.14°C for 60 minutes, and then weighing W2 (g) after cooling;
(4) Calculation: W1-W2 resin content (%)=(W1-W2)/W1*1002.
2. Measurement of circuit board resin flow rate (%):
(1) Test piece production: According to the fiber direction of the circuit board electroplating prepreg, cut into 100*100 (mm) pieces of about 20 g test pieces at a 45° angle;
(2) Weighing: Use a balance with an accuracy of 0.001 grams to accurately weigh W1 (grams);
(3) Heating and pressing: the temperature of the heating plate of the pressing bed is adjusted to 171±3 degree Celsius, when the test piece is placed in the heating plate, the pressure is 14±2Kg/cm2 or more, heating and pressing for 5 minutes, the glue is cut off and combined Weigh W2 (g);
(4) Calculation: Resin flow rate (%)=(W1-W2)/W1*1003.

3. Measurement of circuit board gel time:
(1) Test piece production: According to the fiber direction of the circuit board electroplating prepreg, cut into 50*50 (mm) pieces (each piece about 15 grams) at an angle of 45°;
(2) Heating and pressing: adjust the temperature of the heating plate to 171±3°C and the pressure to 35Kg/cm2 for 15 seconds;
(3) Measurement: The test piece is the result of the measurement from the time the pressure starts to the curing time.
4. Determination of the volatile content of the circuit board:
(1) Test piece production: According to the direction of ////// circuit board electroplating prepreg fiber, cut into 100*100 (mm) 1 piece at a 45° angle;
(2) Weighing: Weigh W1 (grams) using a balance with an accuracy of 0.001 grams;
(3) Heating: Use an air circulating constant temperature bath, heat at 163±3°C for 15 minutes, and then weigh W2 (grams) with a balance;
(4) Calculation: Volatile content (%)=(W1-W2)/W1*100.