Semiconductor device manufacturing: process – Coating with electrically or thermally conductive material – To form ohmic contact to semiconductive material
Reexamination Certificate
1999-05-10
2001-04-10
Picardat, Kevin M. (Department: 2822)
Semiconductor device manufacturing: process
Coating with electrically or thermally conductive material
To form ohmic contact to semiconductive material
C438S612000, C228S179100, C228S180500
Reexamination Certificate
active
06214718
ABSTRACT:
BACKGROUND OF THE INVENTION
The present invention relates to a semiconductor assembling method and apparatus for joining semiconductor chips with lead frames and the like in semiconductor fabrication processes.
Semiconductor chips are connected with external electrodes, such as lead frames, by means of a wire made of gold, aluminium or the like and by using a wire bonder. This wire is connected with the semiconductor chips or external electrodes by heat or ultrasonic waves or by both.
Among the wire bonders, in each of those using the bonding process so called ball bonding, a ball is formed at the tip of the wire by electric discharge or other heating means. The junction conditions for this process include the temperature of the stage at which semiconductor chips and external electrodes are heated, the pressure with which the wire is pressed as well as its time, and the oscillation output of ultrasonic waves as well as its time.
These conditions are previously stored as data in the wire bonder. These data are given as fixed data in all, or fixed data for each wire.
In the case where the wire bonder performs bonding processes continuously for a plurality of wires, the pressurizing tool receives heat from the semiconductor chip heater, resulting in a temperature rise. The ball also comes to a high temperature because the bonding process is carried out immediately after the formation of the ball.
However, when the interval from one bonding process to another is prolonged, for example, during the transfer of semiconductor chips or at a restart after a halt, the temperature of the pressurizing tool or the ball would, lower. This poses an issue that the alloying of the wire and the semiconductor chip is suppressed such that a deterioration in the bondability may occur.
SUMMARY OF THE INVENTION
An object of the present invention is therefore to provide semiconductor assembling method and apparatus which allow the junction to be accomplished without being affected by temperature decreases of the pressurizing tool or the ball even if the interval to the subsequent bonding process is prolonged.
In accomplishing these and other objects, according to a first aspect of the present invention, there is provided a semiconductor assembling method for joining a bonding wire with a bonding object by pressing the bonding wire against the bonding object with a bonding pressurizing tool and by effecting at least one junction process of thermal junction or ultrasonic junction,
the semiconductor assembling method comprising steps of:
measuring a time elapsing from a last bonding process to a subsequent bonding process; and
changing at least one junction condition of pressurizing force, pressurizing time, ultrasonic oscillation output, and ultrasonic oscillation time for the subsequent bonding process, based on the measured time.
According to a second aspect of the present invention, there is provided a semiconductor assembling method for joining a bonding wire with a bonding object by pressing the bonding wire against the bonding object with a bonding pressurizing tool and by effecting at least one junction process of thermal junction or ultrasonic junction,
the semiconductor assembling method comprising steps of:
measuring a temperature of the pressurizing tool; and
changing at least one junction condition of pressurizing force, pressurizing time, ultrasonic oscillation output, and ultrasonic oscillation time for the subsequent bonding process, based on the measured temperature.
According to a third aspect of the present invention, there is provided a semiconductor assembling method for joining a bonding wire with a bonding object by forming a ball at a tip of the bonding wire with energy applied to the bonding wire, by pressing the bonding wire against the bonding object with a bonding pressurizing tool, and by effecting at least one junction process of thermal junction or ultrasonic junction,
the semiconductor assembling method comprising steps of:
measuring a temperature of the tip of the bonding wire; and
changing at least one junction condition of pressurizing force, pressurizing time, ultrasonic oscillation output, and ultrasonic oscillation time for the subsequent bonding process, based on the measured temperature.
According to a fourth aspect of the present invention, there is provided a semiconductor assembling method for joining a bonding wire with a bonding object by pressing the bonding wire against the bonding object with a bonding pressurizing tool and by effecting at least one junction process of thermal junction or ultrasonic junction,
the semiconductor assembling method comprising steps of:
measuring a time elapsing from when a ball is formed at a tip of the bonding wire with energy applied to the bonding wire until when the bonding wire is pressed against the bonding object with the bonding pressurizing tool; and
changing at least one junction condition of pressurizing force, pressurizing time, ultrasonic oscillation output, and ultrasonic oscillation time for the subsequent bonding process, based on the measured time.
According to a fifth aspect of the present invention, there is provided a semiconductor assembling apparatus for joining a bonding wire with a bonding object by pressing the bonding wire against the bonding object with a bonding pressurizing tool and by effecting at least one junction process of thermal junction or ultrasonic junction,
the semiconductor assembling apparatus comprising:
a bonding-interval measuring means for measuring a time elapsing from a last bonding process to a subsequent bonding process; and
a junction condition changing means for changing at least one junction condition of pressurizing force, pressurizing time, ultrasonic oscillation output, and ultrasonic oscillation time for the subsequent bonding process, based on the measured time.
According to a sixth aspect of the present invention, there is provided a semiconductor assembling apparatus for joining a bonding wire with a bonding object by pressing the bonding wire against the bonding object with a bonding pressurizing tool and by effecting at least one junction process of thermal junction or ultrasonic junction,
the semiconductor assembling apparatus comprising:
a pressurizing tool temperature measuring means for detecting a temperature of the pressurizing tool; and
a junction condition changing means for changing at least one junction condition of pressurizing force, pressurizing time, ultrasonic oscillation output, and ultrasonic oscillation time for the subsequent bonding process, based on the measured temperature of the pressurizing tool.
According to a seventh aspect of the present invention, there is a semiconductor assembling apparatus for joining a bonding wire with a bonding object by pressing the bonding wire against the bonding object with a bonding pressurizing tool and by effecting at least one junction process of thermal junction or ultrasonic junction,
the semiconductor assembling apparatus comprising:
a ball forming means for forming a ball at a tip of the bonding wire with energy applied to the bonding wire;
a time measuring means for measuring a time elapsing from the formation of the ball at the tip of the bonding wire by the ball forming means until the subsequent bonding process; and
a junction condition changing means for changing at least one junction condition of pressurizing force, pressurizing time, ultrasonic oscillation output, and ultrasonic oscillation time for the subsequent bonding process, based on the measured time.
According to an eighth aspect of the present invention, there is provided a semiconductor assembling apparatus for joining a bonding wire with a bonding object by pressing the bonding wire against the bonding object with a bonding pressurizing tool and by effecting at least one junction process of thermal junction or ultrasonic junction,
the semiconductor assembling apparatus comprising:
a ball forming means for forming a ball at a tip of the bonding wire with energy applied to the bonding wire;
a temperature measuring means for measuring a te
Eguchi Shinzou
Nagai Yoshiyuki
Matsushita Electric - Industrial Co., Ltd.
Picardat Kevin M.
Wenderoth , Lind & Ponack, L.L.P.
LandOfFree
Semiconductor assembling method and apparatus does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Semiconductor assembling method and apparatus, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Semiconductor assembling method and apparatus will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-2446210