Patent ID: 8677614

Claim:
A device mounting method comprising: placing a bonding head, on which a device is loaded, at a preparation height above a board; determining a search height at which a mounting position on the board, on which the device is to be mounted, is searched for; and lowering the bonding head from the preparation height to a bonding height via the search height, and mounting the device on the mounting position on the board, wherein the lowering and mounting comprises determining whether the device touches the board by performing at least one of following operations: (a) obtaining a command height of the bonding head input by a controller of the bonding head and an actual height of the bonding head at two successive time points, obtaining a difference between the command height and the actual height at the two successive time points, and determining whether a first condition is satisfied, the first condition being that the difference at a later time point is greater than the difference at an earlier time point; (b) obtaining an actual velocity of the bonding head, comparing the actual velocity with a first reference value, and determining whether a second condition is satisfied, the second condition being that the actual velocity is lower than the first reference value; and (c) obtaining the actual height of the bonding head, comparing the actual height with a predetermined range of heights of the bonding head, and determining whether a third condition is satisfied, the third condition being that the actual height is within the predetermined range, wherein the method further comprises determining that the device touches the board if at least one of the first, second and third conditions is satisfied, wherein the difference between the command height and the actual height at each of the two successive time points comprises a height error, and wherein the obtaining the difference comprises: obtaining a height error for the each of the two successive time points; and calculating a variation in height error by subtracting a previous height error from a current height error.