Ultrasonic vibration mode for wire bonding

• US 6,367,685 B1
• Filed: 11/15/2000
• Issued: 04/09/2002
• Est. Priority Date: 04/16/1999
• Status: Expired due to Fees

• Current Assignee: Micron Technology, Inc.
• Original Assignee: Micron Technology, Inc.
• Inventors: Jiang, Tongbi, Wu, Zhiqiang
• Primary Examiner(s): Dunn, Tom
• Assistant Examiner(s): JOHNSON, JONATHAN J
• Application Number:
  US09/819,030
• Time in Patent Office: 510 Days
• Field of Search: 228/180.5, 228/110.1, 228/178, 228/179, 228/180.22, 228/1.1, 228/25, 228/28, 228/29, 156/73.2, 156/580.1, 156/580.2
• US Class Current: 228/180.5
• CPC Class Codes: B23K 20/004 Wire welding
• CPC Class Codes: B23K 2101/38 Conductors
• CPC Class Codes: H01L 2224/05624 Aluminium [Al] as principal constituent
• CPC Class Codes: H01L 2224/45099 Material
• CPC Class Codes: H01L 2224/45124 Aluminium (Al) as principal constituent
• CPC Class Codes: H01L 2224/45144 Gold (Au) as principal constituent
• CPC Class Codes: H01L 2224/48091 Arched
• CPC Class Codes: H01L 2224/48247 connecting the wire to a bond pad of the item
• CPC Class Codes: H01L 2224/48465 the other connecting portion not on the bonding area being a wedge bond, i.e. ball-to-wedge, regular stitch
• CPC Class Codes: H01L 2224/48624 Aluminium (Al) as principal constituent
• CPC Class Codes: H01L 2224/48724 Aluminium (Al) as principal constituent
• CPC Class Codes: H01L 2224/78301 Capillary
• CPC Class Codes: H01L 2224/78347 Piezoelectric transducers
• CPC Class Codes: H01L 2224/78822 Rotational mechanism
• CPC Class Codes: H01L 2224/85045 using a corona discharge, e.g. electronic flame off [EFO]
• CPC Class Codes: H01L 2224/85181 connecting first on the semiconductor or solid-state body, i.e. on-chip, regular stitch
• CPC Class Codes: H01L 2224/85205 Ultrasonic bonding
• CPC Class Codes: H01L 2224/85206 Direction of oscillation
• CPC Class Codes: H01L 24/45 of an individual wire connector
• CPC Class Codes: H01L 24/48 of an individual wire connector
• CPC Class Codes: H01L 24/78 : Apparatus for connecting with wire connectors
• CPC Class Codes: H01L 24/85 : using a wire connector wire bonding in general B23K20/004
• CPC Class Codes: H01L 2924/00 : Indexing scheme for arrangements or methods for connecting or disconnecting semiconductor or solid-state bodies as covered by H01L24/00
• CPC Class Codes: H01L 2924/00014 : the subject-matter covered by the group, the symbol of which is combined with the symbol of this group, being disclosed without further technical details
• CPC Class Codes: H01L 2924/00015 : the subject-matter covered by the group, the symbol of which is combined with the symbol of this group, being disclosed as prior art
• CPC Class Codes: H01L 2924/01005 : Boron [B]
• CPC Class Codes: H01L 2924/01006 : Carbon [C]
• CPC Class Codes: H01L 2924/01013 : Aluminum [Al]
• CPC Class Codes: H01L 2924/01014 : Silicon [Si]
• CPC Class Codes: H01L 2924/01019 : Potassium [K]
• CPC Class Codes: H01L 2924/01029 : Copper [Cu]
• CPC Class Codes: H01L 2924/01033 : Arsenic [As]
• CPC Class Codes: H01L 2924/01039 : Yttrium [Y]
• CPC Class Codes: H01L 2924/01075 : Rhenium [Re]
• CPC Class Codes: H01L 2924/01079 : Gold [Au]
• CPC Class Codes: H01L 2924/01082 : Lead [Pb]
• CPC Class Codes: H01L 2924/14 : Integrated circuits
• CPC Class Codes: H01L 2924/15747 : Copper [Cu] as principal constituent
• CPC Class Codes: H01L 2924/20303 : Ultrasonic frequency [f] 50 Khz=<f< 75 KHz
• CPC Class Codes: H01L 2924/20305 : Ultrasonic frequency [f] 100 Khz=<f< 125 KHz

Abstract

A method and apparatus for creating second order vibrational modes. The apparatus includes a signal generator, a piezoelectric transducer, a plurality of wave propagating beams and reflecting boards. An electric field applied by the signal generator to the piezoelectric transducer induces a unidirectional vibration of the transducer. The vibration is propagated through the beams and reflected by the reflecting boards in a closed polygonal loop. The final reflection direction is perpendicular to the original vibration. A circular or elliptical vibration of the apparatus results. The circular or elliptical vibrational energy can be imparted to the wire bond of an integrated circuit to add strength to the connection.

Claims

1. A wire bonding apparatus, comprising:

a capillary having a lumen therein adapted to receive a bonding wire therein, said bonding wire having a ball formed on a distal end thereof extending at least partially out of said capillary;

an ultrasonic transducer, coupled to said capillary and adapted to impart ultrasonic vibrational energy to said capillary;

wherein said ultrasonic transducer comprises;

a transducer for generating vibrational energy;

a signal generator for applying drive signals to said transducer;

a polygonal ultrasonic wave-propagating arm coupled to said transducer, said polygonal arm comprising a plurality of beams and at least one fixed reflection board, said beams and said at least one fixed reflection board cooperating to angularly reflect said vibrational energy such that said capillary vibrates in a substantially circular or elliptical vibration mode.

3. A wire bonding apparatus in accordance with claim 1 or 2, wherein said transducer comprises a piezoelectric ceramic.

4. A wire bonding apparatus in accordance with claim 1 or 2, wherein said capillary is adapted to target a bond pad on a silicon substrate.

5. A wire bonding apparatus in accordance with claim 1 or 2, wherein said arm has a substantially triangular shape.

6. A wire bonding apparatus in accordance with claim 1 or 2, wherein said arm is mechanically coupled to said transducer.

7. A wire bonding apparatus in accordance with claim 6, wherein said capillary is mechanically coupled to said arm.

8. A wire bonding apparatus in accordance with claim 7, wherein said capillary vibrates in a substantially circular mode.

9. A wire bonding apparatus in accordance with claim 7, wherein said capillary vibrates in a substantially elliptical mode.

10. A wire bonding apparatus in accordance with claim 1, wherein the collective length of said beams comprising said polygonal arm is governed by:

11. A wire bonding apparatus in accordance with claim 1, wherein the total length of said beam is governed by:

12. A wire bonding apparatus in accordance with claim 1, wherein said at least one reflection board is rigidly coupled to at least one of said plurality of beams.

13. A wire bonding apparatus in accordance with claim 12, wherein said at least one reflection board is rigidly coupled to at least one of said plurality of beams at a connection point between two of said plurality of beams.

14. A wire bonding apparatus in accordance with claim 1, wherein said at least one reflection board comprises a material with an overall high Young'"'"'s Modulus than the material comprising said plurality of beams.

2. A wire bonding apparatus, comprising:

a capillary having a lumen therein adapted to receive a bonding wire therein, said bonding wire having a ball formed on a distal end thereof extending at least partially out of said capillary;

an ultrasonic transducer, coupled to said capillary and adapted to impart ultrasonic vibrational energy to said capillary;

wherein said ultrasonic transducer comprises;

a transducer for generating vibrational energy;

a signal generator for applying drive signals to said transducer;

an ultrasonic wave-propagating arm coupled to said transducer, said arm comprising a single beam configured in a closed loop to angularly redirect said vibrational energy such that said capillary vibrates in a substantially circular or elliptical vibration mode.