Si Characterization on Thinning and Singulation Processes for 2.5/3D HBM Package Integration

Area of Science:

• Materials Science
• Semiconductor Manufacturing

Background:

• Advanced semiconductor packaging relies on 2.5D and 3D stacking technologies.
• Wafer thinning and singulation are critical for producing thinner, reliable Si chips, but their impact on chip integrity requires further research.

Purpose of the Study:

• To systematically compare the effects of wafer thinning and singulation processes on the fracture strength of Si wafers.
• To identify optimal processing techniques for enhancing Si chip reliability in advanced packaging.

Main Methods:

• Wafer thinning using fine grinding, poly-grinding, and polishing.
• Surface morphology and roughness analysis via scanning electron microscopy and interferometry.
• Residual stress measurement using Raman spectroscopy.
• Fracture strength assessment via three-point bending tests.
• Singulation methods evaluated: blade dicing, laser dicing, and stealth dicing.

Main Results:

• Polishing resulted in minimal residual stress and surface defects, leading to the highest fracture strength in thinned Si wafers and chips.
• Thinner wafers (60 µm) exhibited higher fracture strength than thicker ones (90 µm, 120 µm) due to increased flexibility.
• Stealth dicing provided superior fracture strength compared to blade and laser dicing.

Conclusions:

• Combining wafer thinning via polishing and singulation via stealth dicing offers an optimal approach for high-reliability Si chip production.
• These findings provide valuable guidance for selecting processing technologies in industrial settings for 2.5D and 3D packaging.