How to solve the problem of circuit board warpage

1. Engineering design: the inter-layer prepreg arrangement should correspond; the multi-layer core board and prepreg should use the same supplier product; the outer C/S surface area should be as close as possible, and a separate grid can be used;

2, before baking, drying board: generally 150 degrees 6-10 hours, remove the water vapor inside the board, further cure the resin completely, eliminate the stress inside the board; before the material is baked, whether it is inside or both sides!

3, before the multi-layer laminated platen should pay attention to the latitude and longitude direction of the cured plate: the warp and weft shrinkage ratio is different, the prepreg should pay attention to the warp and weft direction before lamination; the core plate should also pay attention to the warp and weft direction; The direction of the film roll is the warp direction; the long direction of the copper clad plate is the warp direction;

4, the thickness of the laminate to eliminate stress After the pressure plate is cold pressed, trimming the burrs;

5, before the drilling of the baking sheet: 150 degrees 4 hours;

6, the thin plate is best not to be mechanically brushed, it is recommended to use chemical cleaning; special fixtures are used during plating to prevent the board from bending and folding;

7. After the tin is sprayed, it is naturally cooled to room temperature on the flat marble or steel plate or cleaned after the air floating bed is cooled. The warping plate treatment: 150 degrees or hot pressing for 3-6 hours, using a smooth and smooth steel plate, 2-3 Secondary baking.