US6001724A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Method for forming bumps on a semiconductor die using applied voltage pulses to an aluminum wire
Assignee: Micron Technology Inc
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Filing: 1997-11-24
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Granted: 1999-12-14
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Expires: 2017-11-24
Abstract
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.
Inventors
- 👤 Darryl M. Stansbury
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-02 22:43
CPC Classifications
H; H10; H10W; H10W72/00; H10W72/01; H10W72/012; H10W72/01221; H10W72/01225; H10W72/071; H10W72/072; H10W72/07251; H10W72/20; H10W72/251; H10W72/252; H10W72/50; H10W72/551; H10W72/552; H10W72/5524; H10W72/90; H10W72/921; H10W72/923; H10W72/951; H10W72/952
Claims Analysis
Total Claims: 23
Claim 1
Independent Claim
192 words
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.
Claim 2
Independent Claim
192 words
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.
Claim 3
Dependent Claim
22 words
The method of claim 1 wherein the wire comprises an alloy selected from the group consisting of aluminum-silicon alloy and aluminum-magnesium alloy.
Claim 4
Dependent Claim
25 words
The method of claim 1 wherein the sidewall is flared at an angle of about 45° with respect to a longitudinal axis of the tool.
Claim 5
Dependent Claim
16 words
The method of claim 1 further comprising flip chip bonding the die to a supporting substrate.
Claim 6
Dependent Claim
14 words
The method of claim 4 wherein the supporting substrate comprises a field emission display.
Claim 7
Dependent Claim
26 words
The method of claim 1 wherein a percentage by volume of the hydrogen gas to the inert gas at room temperature is about 1 to 25%.
Claim 8
Independent Claim
180 words
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 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.
Claim 9
Independent Claim
180 words
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 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.
Claim 10
Dependent Claim
20 words
The method of claim 7 wherein the wire comprises an alloy selected from the group consisting of aluminum-silicon and aluminum-magnesium.
Claim 11
Dependent Claim
23 words
The method of claim 8 wherein the severing step comprises moving the capillary tool laterally and downwardly with respect to the ball bump.
Claim 12
Dependent Claim
16 words
The method of claim 9 wherein the sidewall is flared at an angle of about 45°.
Claim 13
Dependent Claim
27 words
The method of claim 10 wherein the capillary tool presses the ball bump against the pad with a pressure of between about 50 grams to 300 grams.
Claim 14
Dependent Claim
22 words
The method of claim 11 further comprising bonding the ball bump to a supporting substrate using a chip on glass bonding process.
Claim 15
Independent Claim
205 words
A method for forming a field emission display comprising: 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.
Claim 16
Independent Claim
205 words
A method for forming a field emission display comprising: 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.
Claim 17
Dependent Claim
18 words
The method of claim 13 wherein the second pad comprises a faceplate of the field emission display package.
Claim 18
Dependent Claim
18 words
The method of claim 13 wherein bonding the ball bump to the second pad comprises flip chip bonding.
Claim 19
Dependent Claim
19 words
The method of claim 13 wherein bonding the ball bump to the second pad comprises chip on glass bonding.
Claim 20
Dependent Claim
26 words
The method of claim 13 wherein a percentage by volume of the hydrogen gas to the inert gas at room temperature is about 1 to 25%.
Claim 21
Dependent Claim
19 words
The method of claim 13 wherein bonding the ball bump to the second pad comprises chip on flex bonding.
Claim 22
Dependent Claim
21 words
The method of claim 13 wherein the wire comprises an aluminum alloy selected from the group consisting of aluminum-silicon and aluminum-magnesium.
Claim 23
Dependent Claim
16 words
The method of claim 13 wherein the die comprises field emitter sites aligned with the faceplate.
References Cited (Backward Citations)
US3380155A
Cited
US3654694A
Cited
US4098447A
Cited
US4323759A
Cited
US4388512A
Cited
US4390771A
Cited
US4476366A
Cited
EP0133118A2
Cited
US4594493A
Cited
US4661192A
Cited
US5302550A
Cited
US5014111A
Cited
US4889275A
Cited
US5395037A
Cited
US5249450A
Cited
US5249732A
Cited
US5386624A
Cited
US5457356A
Cited
US5612256A
Cited
US5578527A
Cited
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| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
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| 3.5 Years (Year 4) | 2002-12-13 | 2003-06-14 | 2003-12-14 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2006-12-13 | 2007-06-14 | 2007-12-14 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2010-12-13 | 2011-06-14 | 2011-12-14 | $7700.00 | Window Closed / Lapsed |