Quality inspection method for electroplating semi cured sheets of printed circuit boards

Quality inspection method for electroplating semi cured sheets of printed circuit boards

Pre impregnated material is a sheet-like material composed of resin and carrier. The resin is in the B-stage, under the action of temperature and pressure, has fluidity and can quickly cure and complete the bonding process, and together with the carrier, forms an insulation layer. Commonly known as semi cured sheet or adhesive sheet. To ensure the high reliability and quality stability of multi-layer printed circuit boards, it is necessary to conduct quality testing (test lamination method) on the characteristics of semi-solid chips. The characteristics of circuit board electroplating semi cured sheets include two parts: 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 performance, thermal shock performance, flammability, etc. Therefore, in order to ensure the high reliability of multi-layer printed circuit boards and the stability of lamination process parameters, it is very important to detect the characteristics of the pre lamination printed circuit board electroplating semi cured sheets.

1. Determination of resin content (%) in circuit boards:

(1) Preparation of test pieces: Cut into 100 pieces at a 45 ° angle according to the fiber direction of the electroplated semi cured sheet of the circuit board × 100 (mm) small test block;

(2) Weighing: Use a balance with an accuracy of 0.001 grams to weigh Wl (grams);

(3) Heating: Heat and burn at 566.14 ℃ for 60 minutes, then weigh W2 (grams) after cooling;

(4) Calculation: W1-W2 resin content (%)=(W1-W2)/W1 × 1002。

2. Determination of resin flow rate (%) for circuit boards:

(1) Sample production: Cut into 100 pieces at a 45 ° angle according to the fiber direction of the electroplated semi cured sheet of the circuit board × 100 (mm) pieces of approximately 20 grams of test pieces;

(2) Weighing: Use a balance with an accuracy of 0.001 grams to accurately weigh W1 (grams);

(3) Heating and pressurization: Adjust the temperature of the heating plate of the press bed to 171 ± 3 ℃. When the test piece is placed in the heating plate, apply a pressure of 14 ± 2Kg/cm2 or more, heat and pressurize for 5 minutes, cut off the outflow glue and weigh W2 (grams);

(4) Calculation: Resin flow rate (%)=(W1-W2)/W1 × one thousand and three

3. Gel time measurement of circuit board:

(1) Test piece production: Cut the fiber direction of the electroplated semi cured sheet of the circuit board into 50 pieces at a 45 ° angle × 50 (mm) pieces (approximately 15 grams per piece);

(2) Heating and pressurization: Adjust the temperature of the heating plate to 171 ± 3 ℃ and the pressure to 35Kg/cm2 for a pressurization time of 15 seconds;

(3) Measurement: The test piece is measured from the start time of pressurization to the curing time.

4. Determination of volatile matter content in circuit boards:

(1) Sample production: Cut into 100 pieces at a 45 ° angle according to the fiber direction of the electroplated semi cured sheet of the circuit board × 100 (mm) 1 piece;

(2) Weighing: Use a balance with an accuracy of 0.001 grams to weigh W1 (grams);

(3) Heating: Use an air circulation constant temperature bath, heat at 163 ± 3 ℃ for 15 minutes, and then weigh W2 (grams) using a balance;

(4) Calculation: Volatile matter (%)=(W1-W2)/W1 × 100。