Improved multilayer circuit board and manufacturing method thereof

[0027] Example 1

[0028] refer to figure 1 shown:

[0029] A manufacturing method of a multilayer circuit board, comprising the following steps:

[0030] S1 Production of the first inner layer board: prepare the first inner layer board 6, the upper and lower ends of the first inner layer board 6 are electroplated, dry filmed and etched to form the first inner layer copper foil 5 and the second inner layer copper foil 7 respectively , the residual copper ratio of the first inner layer copper foil 5 and the second inner layer copper foil 7 after etching is 56%;

[0031] S2 Second inner layer board production: prepare the second inner layer board 12, the upper and lower ends of the second inner layer board 12 are electroplated, dry filmed and etched to form the third inner layer copper foil 11 and the fourth inner layer copper foil 13 respectively , the residual copper rate of the third inner layer copper foil 11 after etching is 51%, and the residual copper rate of the fourth inner layer copper foil 13 after etching is 32%;

[0032] S3 third inner layer board production: prepare the third inner layer board 18, the upper and lower ends of the third inner layer board 18 are electroplated, dry filmed, and etched to form the fifth inner layer copper foil 17 and the sixth inner layer copper foil 19 respectively , the residual copper ratio of the fifth inner layer copper foil 17 and the sixth inner layer copper foil 19 after etching is 56%;

[0033] S4 Lamination: Prepare the first outer copper foil 1, the first glass fiber PP layer 2, the second glass fiber PP layer 3, the third glass fiber PP layer 4, the fourth glass fiber PP layer 8, and the fifth glass fiber PP layer Layer 9, first PP layer 10, second PP layer 14, sixth glass fiber PP layer 15, seventh glass fiber PP layer 16, eighth glass fiber PP layer 20, ninth glass fiber PP layer 21, tenth glass fiber PP layer The fiber PP layer 22 and the second outer layer copper foil 23, wherein the thickness of the first outer layer copper foil 1 and the second outer layer copper foil 23 are both 52.5μm, the thickness of the first PP layer 10 is 0.2mm, and the thickness of the second PP layer 10 is 0.2mm. The thickness of the layer 14 is 0.2mm, the first outer layer copper foil 1, the first glass fiber PP layer 2, the second glass fiber PP layer 3, the third glass fiber PP layer 4, the first inner layer copper foil 5, the first One inner layer board 6, the second inner layer copper foil 7, the fourth glass fiber PP layer 8, the fifth glass fiber PP layer 9, the first PP layer 10, the third inner layer copper foil 11, the second inner layer board 12 , the fourth inner layer copper foil 13, the second PP layer 14, the sixth glass fiber PP layer 15, the seventh glass fiber PP layer 16, the fifth inner layer copper foil 17, the third inner layer board 18, the sixth inner layer The copper foil 19 , the eighth glass fiber PP layer 20 , the ninth glass fiber PP layer 21 , the tenth glass fiber PP layer 22 , and the second outer copper foil 23 are stacked in order from top to bottom, and then placed in a pressing machine to press Synthetic type to obtain semi-finished products;

[0034] S5 copper reduction: reduce the copper of the semi-finished product through the copper reduction wire, so that the thicknesses of the first outer layer copper foil 1 and the second outer layer copper foil 23 are reduced to 35 μm;

[0035] S6 dry film: a layer of dry film is pressed on the upper end surface of the first outer layer copper foil 1 and the lower end surface of the second outer layer copper foil 23. After exposure and development, the dry film is attached to the upper end of the circuit area;

[0036] S7 one test: test the above-mentioned dry film bonding, and the test results are recorded in Table 1 below;

[0037] S8 etching: The copper foil in the non-circuit area is removed by the etching solution, and finally the dry film is removed to make a multi-layer circuit board. The multi-layer circuit board includes the first outer layer copper foil 1, the first glass Fiber PP layer 2, second glass fiber PP layer 3, third glass fiber PP layer 4, first inner layer copper foil 5, first inner layer board 6, second inner layer copper foil 7, fourth glass fiber PP layer 8. The fifth glass fiber PP layer 9, the first PP layer 10, the third inner layer copper foil 11, the second inner layer board 12, the fourth inner layer copper foil 13, the second PP layer 14, the sixth glass fiber PP layer Layer 15, seventh glass fiber PP layer 16, fifth inner layer copper foil 17, third inner layer board 18, sixth inner layer copper foil 19, eighth glass fiber PP layer 20, ninth glass fiber PP layer 21, The tenth glass fiber PP layer 22 and the second outer layer copper foil 23;

[0038]S9 secondary test: The above-mentioned first outer layer copper foil 1 and second outer layer copper foil 23 are tested for the forming conditions, and the test results are recorded in Table 1 below.