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Michael Mayer

Jonathan Medding

Martin Melzer

J&uuml;rg Schwizer

Jürg Schwizer

A predetermined number of bond cycles is carried out in order to find optimum bond parameters for a wire bonder. The bond parameters to be optimized are each varied within a predefined range. With each bond cycle, after attachment of the wire to the connection point, the capillary is moved out of the bond position in a predetermined horizontal direction whereby the current flowing through the drive which moves the capillary is monitored and its maximum determined.

Method for determining optimum bond parameters when bonding with a wire bonder

A method for finding optimum bond parameters for a bond force Fand an ultrasonic variable P and, optionally, at least one further bond parameter of a wire bonder uses a sensor sensitive to a shear force exerted by the capillary on a connection point. A predetermined number of bonding operations with varying bonding parameters is performed. Optimum bond parameters are derived from the signal of the sensor.

Method for determining optimum bonding parameters for bonding with a wire bonder

In order that, on wire bonding by means of a Wire Bonder, optimum bonding results can be achieved after a capillary change it is suggested that, after a change from a first capillary to a second capillary, the ultrasonic transducer which applies ultrasonics to the horn which guides the capillary is controlled with a parameter P which results from the parameter P before the capillary change as P &equals;g(k , k )*P or P &equals;g(k , k , A , A )*P or P &equals;g(k , k , A , A , H , H )*P , whereby the quantities k and k designate the estimated values for the flexural strength, the quantities A and A the amplitudes of the freely oscillating capillary and H and H the diameters in the narrowest part of the longitudinal drill hole of the first or second capillary and whereby the function g is a predetermined function.

Method for the calibration of a wire bonder

A Wire Bonder has a capillary clamped to a horn. An ultrasonic transducer applies ultrasonics to the horn whereby the ultrasonic transducer is controlled by a parameter P. For calibration of the parameter P, a pizoresistive sensor integrated into a semiconductor chip is used. The capillary is lowered onto the semiconductor chip and a bond force is applied to it. Afterwards, a value P of the parameter P is applied to the ultrasonic transducer and the output signal of the sensor is stored as the reference value U as soon as the transient reaction is concluded. The bond force is selected great enough so that the capillary does not slide back and forth. The Wire Bonder, for example after changing the capillary, is then recalibrated in that a correction factor &ggr; is analogously determined so that the amplitude of the sensor signal assumes the value U when the ultrasonic transducer is operated with the value P &equals;&ggr;*P .

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Michael Mayer