Abstract: A method for measuring thickness of dielectric layer in circuit board includes the following steps: First, circuit board including dielectric layer and circuit layers is provided. The dielectric layer is between the circuit layers, and the circuit board further includes test area including test pattern and through hole. The test pattern includes first conductor and second conductors. The distance between the side of the through hole and the second conductor is less than the distance between the side of the through hole and the first conductor. Next, measuring device including conductive pin and sensing element is provided. Next, the conductive pin is powered, and one end of the conductive pin is electrically connected to the second conductor. Next, the sensing element is moved along the through hole to obtain sensing curve, and the thickness of the dielectric layer is calculated via variations of the sensing curve.

Abstract: A method for measuring thickness of dielectric layer in circuit board includes the following steps: First, circuit board including dielectric layer and circuit layers is provided. The dielectric layer is between the circuit layers, and the circuit board further includes test area including test pattern and through hole. The test pattern includes first conductor and second conductors. The distance between the side of the through hole and the second conductor is less than the distance between the side of the through hole and the first conductor. Next, measuring device including conductive pin and sensing element is provided. Next, the conductive pin is powered, and one end of the conductive pin is electrically connected to the second conductor. Next, the sensing element is moved along the through hole to obtain sensing curve, and the thickness of the dielectric layer is calculated via variations of the sensing curve.