Die Sidewall Coatings for Crack-Free Wafer Singulation
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Solution Overview
Problem
Conventional semiconductor package manufacturing methods using sawing techniques result in chipping and cracking of die sidewalls, limiting the production of non-rectangular die shapes and compromising package reliability.
Innovation Solution
The use of etching techniques to form notches in semiconductor wafers, followed by applying a mold compound and singulating the substrate into packages, which eliminates sidewall cracks and allows for various die shapes, including non-rectangular perimeters.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If sawing techniques are used to singulate semiconductor substrates, then productivity is improved, but manufacturing precision deteriorates due to chipping and cracking of die sidewalls
Solution Approach 1:
The patent replaces the mechanical sawing process with a chemical etching process. Instead of using physical saw blades to cut through the substrate and die, the invention uses chemical etchants to selectively remove material along predefined scribe lines, forming notches that define individual die boundaries. This substitution eliminates mechanical contact with the die sidewalls, preventing chipping and cracking while maintaining high productivity through batch processing of multiple die simultaneously.
Solution Approach 2:
The patent introduces a chemical etchant as an intermediary substance to perform the separation function. The etchant acts as a mediator between the desired separation goal and the physical substrate, enabling precise cutting without direct mechanical force applied to the die. The etchant selectively attacks the substrate material along the scribe lines, creating clean notches that define die boundaries without compromising sidewall integrity.
2Ease of manufacture
If conventional sawing is used, then ease of manufacture is maintained, but reliability deteriorates due to sidewall cracks
Solution Approach 1:
The patent replaces the mechanical sawing process with a chemical etching process. Instead of using physical saw blades to cut through the substrate and die, the invention uses chemical etchants to selectively remove material along predefined scribe lines, forming notches that define individual die boundaries. This substitution eliminates mechanical contact with the die sidewalls, preventing chipping and cracking while maintaining high productivity through batch processing of multiple die simultaneously.
Solution Approach 2:
The patent changes the fundamental parameter of the cutting process from mechanical force to chemical reaction. By controlling parameters such as etchant composition, temperature, exposure time, and etch rate, the process achieves precise material removal without mechanical stress. This parameter change enables clean separation while preserving die integrity, directly improving reliability without significantly complicating the manufacturing process.
3Ease of manufacture
If traditional rectangular die shapes are used, then ease of manufacture is improved, but adaptability deteriorates by limiting non-rectangular die shapes
Solution Approach 1:
The patent applies preliminary patterning to define the desired die shapes before the etching process. Photomasks or other patterning techniques are used to pre-establish the geometric boundaries of each die, including non-rectangular configurations. This preliminary action allows the subsequent chemical etching process to accurately replicate complex shapes without requiring mechanical tooling changes, enabling versatile die geometry while maintaining manufacturing simplicity through a standardized process flow.
Data Source
AI summary
Various implementations of a method of forming a semiconductor package may include forming a plurality of notches into the first side of a semiconductor substrate; applying a permanent coating material into the plurality of notches; forming a first organic material over the first side of the semiconductor substrate and the plurality of notches; thinning a second side of the semiconductor substrate opposite the first side one of to or into the plurality of notches; and singulating the semiconductor substrate through the permanent coating material into a plurality of semiconductor packages.