Wire bonding method employing two scrub settings
A method of attaching bond wires to bond pads on an active surface of a semiconductor die, where the bond pads are disposed along four side edges of the die, and have aluminum top layers. The method includes attaching first bond wires to first bond pads on first and second opposing sides of the die using a first group of settings and attaching second bond wires to the bond pads on third and fourth sides of the die that oppose each other and are adjacent the first and second sides, using a second group of settings. The first and second groups of settings include first and second scrub settings that are different from each other. Employing two separate scrub settings allows for reduced splashing of the aluminum cap layer on the die pad from splashing onto passivation edges of the bond pads.
1. A method of attaching bond wires to bond pads of an integrated circuit die, wherein the integrated circuit die is rectangular and has an active surface with first bond pads located on first and second opposing sides of the die, and second bond pads located on third and fourth opposing sides of the die, wherein the third and fourth sides, respectively are adjacent to the first and second sides and extend in a first direction, and the first and second sides extend in a second direction that is perpendicular to the first direction, the method comprising:
attaching first bond wires to the first bond pads using a first group of settings; and
attaching second bond wires to the second bond pads using a second group of settings that is different from the first group of settings, wherein attaching comprises:
forming a free air ball (FAB) on a tip of the first or second bond wires while the first or second bond wires are held in a capillary;
touching the FAB to a surface of the respective first or second bond pads;
moving the capillary back and forth in the first direction and therefore the FAB against the first or second respective bond pad surface; and
performing a table scrubbing process simultaneously in the second direction with the moving of the capillary.
2. The method of claim 1 , wherein moving the capillary back and forth in the first direction comprises performing an ultrasonic bonding process.
3. The method of claim 1 , wherein in the first group of settings, the table scrubbing in the second direction is set at a first value and in the second group of settings the table scrubbing in the second direction is set at a second value that is greater than the first value.
4. The method of claim 1 , wherein the first group of settings includes a first table scrub setting and the second group of settings includes a second table scrub setting different from the first table scrub setting.
5. The method of claim 4 , wherein the first and second groups of scrub settings include settings for power, force and amplitude.
6. The method of claim 5 , wherein the power setting for the second group of scrub settings is greater than the power setting for the second group of scrub settings.
7. The method of claim 6 , wherein the power setting for the second group of scrub settings is twice that of the power setting for the second group of scrub settings.
8. The method of claim 5 , wherein the force setting for the second group of scrub settings is greater than the force setting of the second group of scrub settings.
9. The method of claim 8 , wherein the force setting for the second group of scrub settings is three times the force setting of the second group of scrub settings.
10. The method of claim 5 , wherein the amplitude setting for the second group of scrub settings is greater than the amplitude setting of the second group of scrub settings.
11. The method of claim 1 , wherein the bond pads have a top layer of aluminum.
12. The method of claim 11 , wherein the bond wires comprise copper.
13. The method of claim 1 , wherein the bond pads have a bond pad opening of 43 um or less.
14. The method of claim 1 , wherein the table scrubbing process is performed by moving a table that has the integrated circuit die held thereupon back and forth.