Patent ID: 7637413

Claim:
An X-ray inspection method for inspecting a solder connection portion between a circuit device and a printed circuit board by using an X-ray inspection device, wherein the circuit device includes a solder ball disposed on a surface of the circuit device facing the printed circuit board, and wherein the printed circuit board includes a land disposed on a position of a surface of the printed circuit board corresponding to the solder ball, the method comprising the steps of: irradiating an X-ray to the solder connection portion by using the X-ray inspection device when the solder ball of the circuit device is bonded to the land of the printed circuit board for forming the solder connection portion between the solder ball and the land; detecting the X-ray transmitted through the solder connection portion; outputting a detection signal corresponding to the detected X-ray; forming and outputting a horizontal tomographic image of the solder connection portion on the basis of the detection signal; measuring a warpage amount of the printed circuit board; compensating the horizontal tomographic image in accordance with the warpage amount; and determining solder wettability failure when no solder bump is disposed in contact with a surface of the land that is intersected by a horizontal plane of the horizontal tomographic image, wherein the horizontal tomographic image shows existence or nonexistence of the solder bump disposed in contact with a surface of the land that is intersected by a horizontal plane of the horizontal tomographic image, the land has a thickness about 40 μm, the printed circuit board further includes a resist, which is separated from the land, a distance between the land and the resist is in a range between 20 μm and 105 μm, and the printed circuit board further includes at least warpage compensation marks on a surface of the printed circuit board to measure the warpage amount.