Method for aligning the bondhead of a Die Bonder
AssigneeUnaxis International Trading Ltd.
InventorStefan Behler
Life of this patent
Estimating the term…
Abstract
In order to eliminate the inclination of a semiconductor chip picked by a gripper, the height of at least three points on the underneath of the semiconductor chip is determined in relation to a reference surface and from this the inclination is calculated. Determining the heights takes place in that the semiconductor chip is lowered until the semiconductor chip comes into contact with a needle.
Claims2
A method for adjusting the bondhead of a Die Bonder, whereby the Die Bonder comprises a bondhead with a gripper deflectable in a predetermined direction in relation to the bondhead, comprising the following steps:
- a) Picking a semiconductor chip or a plate with the gripper of the bondhead;
- b) Moving the bondhead to a position characterised by co-ordinates (x1, y1) that is determined so that the semiconductor chip is located above a needle;
- c) Lowering the bondhead whereby the gripper is located in a bottom limit position in relation to the bondhead and monitoring the output signal of a sensor the output signal of which is dependent on the degree of deflection of the gripper in relation to the bondhead;
- d) Determining a height z1(x1, y1) taken up by the bondhead at the time when the semiconductor chip came into contact with the needle from the output signal of the sensor;
- e) Repeating steps b to d for at least two further positions characterised by co-ordinates (x2, y2) and (x3, y3) and determining the corresponding values z2(x2, y2) and z3(x3, y3) that again correspond to the heights at positions (x2, y2) and (x3, y3) taken up by the bondhead at the time when the semiconductor chip, on lowering the bondhead, came into contact with the needle;
- f) Determining two angles α and β from the values z1(x1, y1), z2(x2, y2) and z3(x3, y3), whereby angle α designates the angle by which the semiconductor chip is rotated on a first axis in relation to its ideal position, and whereby angle β designates the angle by which the semiconductor chip is rotated on a second axis in relation to its ideal position;
- g) Adjusting the bondhead according to the angles α and β determined in step f.
A method for adjusting the bondhead of a Die Bonder, whereby the Die Bonder comprises a bondhead with a gripper deflectable in a predetermined direction in relation to the bondhead, comprising the following steps:
- a) Picking a semiconductor chip or a plate with the gripper of the bondhead;
- b) Moving the bondhead to a position characterised by co-ordinates (x1, y1) that is determined so that the semiconductor chip is located above a needle;
- c) Lowering the gripper and monitoring the output signal of a sensor the output signal of which is dependent on the degree of deflection of the gripper in relation to the bondhead;
- d) Determining a height z1(x1, y1) taken up by the gripper at the time when the semiconductor chip came into contact with the needle from the output signal of the sensor;
- e) Repeating steps b to d for at least two further positions characterised by co-ordinates (x2, y2) and (x3, y3) and determining the corresponding values z2(x2, y2) and z3(x3, y3) that again correspond to the heights at positions (x2, y2) and (x3, y3) taken up by the gripper at the time when the semiconductor chip, on lowering the gripper, came into contact with the needle;
- f) Determining two angles α and β from the values z1(x1, y1), z2(x2, y2) and z3(x3, y3), whereby angle α designates the angle by which the semiconductor chip is rotated on a first axis in relation to its ideal position, and whereby angle β designates the angle by which the semiconductor chip is rotated on a second axis in relation to its ideal position;
- g) Adjusting the bondhead according to the angles α and β determined in step f.
Dependencies are inferred from the claim text.