User:Spheroidite/Wedge bonding

Wedge bonding, a type of wire bonding, is the process of welding wires or ribbons to substrates of various materials to form electronic interconnections through the application of ultrasonic energy and force over time.^[1] Wedge bonding is categorized either fine or heavy wire bonding based on the wire size or as ribbon bonding. Wedge bonding is suited for different applications and requires different manufacturing equipment and approaches.

Mechanism of action

Bond characteristics

Fine (thin) wire bonding uses wire diameters 12.5 to 75 μm (0.5 to 3.0 mils), whereas heavy (thick) wire refers to wire sizes 75 to 600 μm (3 to 24 mils).^[2]^[3]^[4]^[5]^[6]^[7]

The wire bonded joint is made up of the wedge, the deformed wire contact attached to the substrate, the heel (also known as neck), the junction between the wedge and the loop, the loop, the length of wire bridging between the bond contacts, and the tail, the extra length of wire sticking off the end of the first (source) bond.

Dimensional acceptability

Acceptability of bonds is defined by industry,^{[note 1]} military, or internal company standards.

Loops must have a separation clearance of at least 2 times the wire diameter.

Visual acceptability

Heel notches, wire fragments, residue or scratches under the bond, and tool marks are not allowed. Bonds may not be double-bonded.

Pull test acceptability

The pull test limits depend on the type and material properties of the wire. For fine wire, pull force must be greater than 0.3 times the breaking load for destructive testing, and greater than 0.2 times the breaking load for non-destructive testing, whereas for heavy wire the pull force must be greater than 0.75 times the breaking load for destructive testing, and greater than 0.5 times the breaking load for non-destructive testing. The minimum pull test limits for non-destructive^[9] and destructive.^[10]

Shear test acceptability

Minimum shear force = 2*BL
Minimum bond coverage >50%

Applications

Wire bond manufacturing

Quality requirements

Typical requirements in terms of process capability are e.g. automotive long-term load (1.33), automotive short-term load (1.67), consumer (1.33) and industrial (1.33).

$C_{pk}={\frac {min(\mu -LSL;USL-\mu )}{3\sigma }}$

Bonding parameters are developed using the design of experiments method evaluating the visual, dimensional, and test results.

Wire bond equipment

Leading manufacturers of wire bonders are Hesse Mechatronics, F&K Delvotec [de], and Kulicke & Soffa.

Bond wire

Major suppliers of bond wire are Heraeus and Tanaka.

Wedge tools

Major suppliers of wedge tools are Small Precision Tools (SPT), Micro Point Pro (MPP), and Deweyl.

Notes

^ For heavy wire, the bond width (deformation) must be greater than 1.1 and less than 1.6 times the wire diameter. The tail must be greater than 0.5 and less than 3 times the wire diameter. For fine wire, the deformation must be greater than 1.2 and less than 2 times the wire diameter. The tail must be less than 3 times the wire diameter but with at least one piece of un-deformed wire between bond and tear off. Asymmetry must be less than 1.25 times the wire diameter, and wedge length dependent on the tool geometry.^[8]

References

Citations

^ Harman.
^ DVS 2811, p. 3.
^ "Ultrasonic Heavy Wire Bonder M17" (PDF). F&K Delvotec. September 2017. p. 3.
^ "Fine Wire Bonder Bondjet BJ855". Hesse Mechatronics. Technical data.
^ "Ultrasonic Thin Wire Bonder M17" (PDF). F&K Delvotec. September 2017. p. 3.
^ "Heavy Wire Bonder Bondjet BJ985". Hesse Mechatronics. Technical data.
^ "Asterion: Enhanced Capability Hybrid Wedge Bonder" (PDF). Kulicke and Soffa. January 9, 2017. p. 2.
^ DVS2811, p. 25.
^ MIL-STD-883 Method 2023.7 Nondestructive Bond Pull.
^ MIL-STD-883 Method 2011.9 Bond Strength (Destructive Pull Test).

Bibliography

Harman, George G. (2010). Wire Bonding in Microelectronics (3rd ed.). New York: McGraw-Hill. ISBN 978-0-07-164265-1. OCLC 609421363.

Standards

"AEC – Q101-003 Wire Bond Shear Test" (PDF). Component Technical Committee. Automotive Electronics Council. July 18, 2005.
"ASTM F459-13 Standard Test Methods for Measuring Pull Strength of Microelectronic Wire Bonds". ASTM. West Conshohocken, PA: ASTM International. April 10, 2018. doi:10.1520/F0459-13.
"DVS 2811: Test Procedures for Wire Bonded Joints". Technical Committee Working Group: Joining in Electronics and Precision Engineering. Düsseldorf, Germany: German Welding Society [de]. February 2017.
"JESD22-B116B Wire Bond Shear Test Method". JEDEC Standard (22-B116B). Arlington, VA: JEDEC Solid State Technology Association. April 2017.
"MIL-STD-883 Test Method Standard: Microcircuits". Department of Defense. Method 2011.9 Bond Strength (Destructive Pull Test); Method 2023.7 Nondestructive Bond Pull. June 7, 2013.
"IPC-A-610G Acceptability of Electronic Assemblies" (PDF). IPC. Bannockburn, IL. October 2017.
"Test Method 2.4.42.3 Wire Bond Pull Strength" (PDF). IPC-TM-650. Bannockburn, IL: IPC. February 1998. Archived (PDF) from the original on 2022-01-24.

Category:Semiconductor device fabrication Category:Packaging (microfabrication) Category:Welding Category:Electronics manufacturing

[9] For heavy wire, the bond width (deformation) must be greater than 1.1 and less than 1.6 times the wire diameter. The tail must be greater than 0.5 and less than 3 times the wire diameter. For fine wire, the deformation must be greater than 1.2 and less than 2 times the wire diameter. The tail must be less than 3 times the wire diameter but with at least one piece of un-deformed wire between bond and tear off. Asymmetry must be less than 1.25 times the wire diameter, and wedge length dependent on the tool geometry.^[8]

[FOOTNOTEHarman-1] Harman.

[FOOTNOTEDVS_28113-2] DVS 2811, p. 3.

[3] "Ultrasonic Heavy Wire Bonder M17" (PDF). F&K Delvotec. September 2017. p. 3.

[4] "Fine Wire Bonder Bondjet BJ855". Hesse Mechatronics. Technical data.

[5] "Ultrasonic Thin Wire Bonder M17" (PDF). F&K Delvotec. September 2017. p. 3.

[6] "Heavy Wire Bonder Bondjet BJ985". Hesse Mechatronics. Technical data.

[7] "Asterion: Enhanced Capability Hybrid Wedge Bonder" (PDF). Kulicke and Soffa. January 9, 2017. p. 2.

[FOOTNOTEDVS281125-8] DVS2811, p. 25.

[FOOTNOTEMIL-STD-883_Method_2023.7_Nondestructive_Bond_Pull-10] MIL-STD-883 Method 2023.7 Nondestructive Bond Pull.

[FOOTNOTEMIL-STD-883_Method_2011.9_Bond_Strength_(Destructive_Pull_Test)-11] MIL-STD-883 Method 2011.9 Bond Strength (Destructive Pull Test).

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