1. Effect of Die Deflection during Au Wire Bonding Process on Bonding Quality in Overhang Semiconductor Package.
- Author
-
Azahar, Ahmad Zarif, Bakar, Maria Abu, Jalar, Azman, and Ani, Fakhrozi Che
- Subjects
INTERMETALLIC compounds ,OPTICAL microscopes ,SEMICONDUCTORS ,CHEMICAL bond lengths ,WIRE - Abstract
Wire bonding is an interconnection technique widely used in semiconductor packaging. Certain packages employ a stacked die configuration for miniaturization. Thus, the advancement of stacking dies leads to the overhanging structure of the staked dies. The complexity of an overhang generates challenges in the wire bonding process, whereby the bonding location has no supporting structure, leading to poor bondability due to die deflection. Thus, this paper studies the wire bonding quality on overhang stacked die structures. The experimental work focuses on the wire bonding process of more than 50 Au (gold) wires on more than 50 Al (aluminum) bonding sites with a variation of overhang distance, t ranged from 5 to 11.7 and wire bonding force, x ranged from 3 to 13. Analysis of the wire bonding quality is focused on die deflection during the wire bonding process. After the wire bonding process, intermetallic compound (IMC) formation was determined between the Au wire and Al bond pad using an optical microscope. The IMC was analyzed to determine the IMC coverage. The findings show that higher overhang distance and bonding force contribute to higher die deflection values during the wire bonding process. The die deflection is higher at the corner region of bonding points compared to the middle region bonding sites. Thus, this work suggests the refined average values to represent the true die deflection values by ignoring the "corner" region values. IMC coverage results show less coverage as the overhang distance and bonding force are increased. This work shows good wire bonding quality can be obtained by using a lower bonding force of 13 x , and lower overhang distance of 11.7 t . This could prevent the non-established wire bonding for overhang structure, at least for a die thickness of 31 µm. [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
- View/download PDF