Method for forming bumps on a semiconductor die using applied voltage pulses to an aluminum wire
First Claim
1. A method for forming a bump on a pad of a semiconductor die, comprising:
- providing a wire comprising aluminum;
providing a ball bonding apparatus comprising a negative electrode, and a capillary tool with an opening for holding the wire having a flared sidewall on a terminal end thereof;
forming a molten ball on the wire using electronic flame off performed using the apparatus by applying a plurality of voltage pulses of about 15,000 and 30,000 volts to the wire and to the negative electrode, in a forming gas comprising hydrogen gas and an inert gas to prevent oxidation hardening of the molten ball;
shaping the molten ball into a ball bump with a neck portion attached to the wire by pressing the molten ball against the sidewall;
following the shaping step, attaching the ball bump to the pad by vibrating and pressing the ball bump against the pad using the capillary tool;
heating the ball bump during the attaching step to a temperature of about 80°
C. to 150°
C.; and
following the attaching step, severing the wire from the ball bump at the neck portion thereof by manipulating the capillary tool.
6 Assignments
0 Petitions
Accused Products
Abstract
A method of forming ball bumps on a pad of a semiconductor die using aluminum wire is provided. The method includes providing an aluminum wire and a thermosonic ball bonding apparatus. The aluminum wire is held in a capillary tool of the ball bonding apparatus and a molten ball is formed on the wire using an electronic flame off (EFO). A forming gas comprising hydrogen and an inert gas, prevents the molten ball from oxidation hardening during formation thereof. Following formation, the molten ball is shaped into a ball bump by the capillary tool and then pressed against the pad while the capillary tool is vibrated. The completed die can be bonded to a substrate pad on a supporting substrate by using a bonding technique such as flip chip bonding, chip on glass bonding, chip on flex bonding, TAB bonding, and z-axis adhesive bonding.
45 Citations
20 Claims
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1. A method for forming a bump on a pad of a semiconductor die, comprising:
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providing a wire comprising aluminum; providing a ball bonding apparatus comprising a negative electrode, and a capillary tool with an opening for holding the wire having a flared sidewall on a terminal end thereof; forming a molten ball on the wire using electronic flame off performed using the apparatus by applying a plurality of voltage pulses of about 15,000 and 30,000 volts to the wire and to the negative electrode, in a forming gas comprising hydrogen gas and an inert gas to prevent oxidation hardening of the molten ball; shaping the molten ball into a ball bump with a neck portion attached to the wire by pressing the molten ball against the sidewall; following the shaping step, attaching the ball bump to the pad by vibrating and pressing the ball bump against the pad using the capillary tool; heating the ball bump during the attaching step to a temperature of about 80°
C. to 150°
C.; andfollowing the attaching step, severing the wire from the ball bump at the neck portion thereof by manipulating the capillary tool. - View Dependent Claims (2, 3, 4, 5, 6)
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7. A method for forming a bump on a pad of a semiconductor die, comprising:
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providing a wire comprising aluminum; providing a ball bonding apparatus comprising a negative electrode and a capillary tool for holding the wire having an opening with a flared sidewall on a terminal end thereof; forming a molten ball on the aluminum wire by electronic flame off performed using the apparatus by applying a plurality of voltage pulses of about 15,000 volts to 30,000 volts to the wire and to the negative electrode, in a forming gas comprising hydrogen and an inert gas to prevent oxidation hardening of the molten ball; shaping the molten ball by pressing the molten ball against the sidewall to form a ball bump attached at a neck portion to the wire; heating the ball bump to a temperature of between about 80°
C. to 150°
C.;vibrating the capillary tool and pressing the ball bump against the pad; and following the vibrating step, severing the ball bump at the neck portion by moving the capillary tool with respect to the ball bump. - View Dependent Claims (8, 9, 10, 11, 12)
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13. A method for forming a field emission display comprising:
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providing a wire comprising aluminum; providing a semiconductor die comprising a pad; providing a ball bonding apparatus comprising a negative electrode and a capillary tool for holding the wire having a flared sidewall on a terminal end thereof; forming a molten ball on the wire using electronic flame off performed using the apparatus by applying a plurality of voltage pulses to the wire and to the negative electrode, in a forming gas comprising hydrogen and an inert gas to prevent oxidation hardening of the molten ball; shaping the molten ball into a ball bump by manipulation of the capillary tool or the wire and contact of the molten ball with the sidewall, the ball bump including a neck portion attached to the wire; attaching the ball bump to the pad by vibrating and pressing the ball bump against the pad using the capillary tool; heating the ball bump to a temperature of about 80°
C. to 150°
C. during the attaching step;following the attaching step, severing the wire from the ball bump at the neck portion by manipulating the capillary tool; and bonding the ball bump to a second pad on the field emission display. - View Dependent Claims (14, 15, 16, 17, 18, 19, 20)
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Specification