Semiconductor Die Separation via Plasma Etching
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Solution Overview
Problem
Conventional sawing methods for separating semiconductor dies from a wafer often result in chipping and crack formation, impacting the reliability and electrical functionality of the chips.
Innovation Solution
A method involving selective removal of portions between dies on a carrier, followed by the formation of a backside metallization layer to package the dies, while preventing metal deposition into dicing grooves, using techniques like plasma etching and electrochemical deposition.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If sawing is used to separate dies from wafer, then dies can be separated, but chipping and crack formation occur impacting reliability
Solution Approach 1:
The patent replaces the conventional mechanical sawing process with a chemical etching process. Instead of using a physical saw blade to cut through the wafer and separate dies, the invention uses selective chemical etchants to remove material and create separation grooves. This substitution eliminates mechanical contact between the cutting tool and the die edges, thereby preventing chipping and crack formation while maintaining effective die separation.
Solution Approach 2:
The patent changes the fundamental parameter of the separation process from mechanical force to chemical reaction. By controlling etching parameters such as etchant composition, temperature, and exposure time, the process achieves precise material removal without the mechanical stresses that cause chipping. The chemical etching allows for controlled material removal at the molecular level rather than through mechanical fracture.
2Ease of manufacture
If conventional dicing is used to separate dies, then separation is achieved, but electrical functionality may be impacted due to damage
Solution Approach 1:
The patent replaces the conventional mechanical sawing process with a chemical etching process. Instead of using a physical saw blade to cut through the wafer and separate dies, the invention uses selective chemical etchants to remove material and create separation grooves. This substitution eliminates mechanical contact between the cutting tool and the die edges, thereby preventing chipping and crack formation while maintaining effective die separation.
3Productivity
If backside metallization is formed before separation, then packaging efficiency improves, but metal may deposit into dicing grooves
Solution Approach 1:
The patent performs the metallization process on the entire wafer backside before the separation step. By forming the metallization layer while all dies are still mounted on the wafer, the process achieves better alignment and coverage. The metallization is deposited across the full wafer surface in a single operation, improving productivity compared to processing individual separated dies. The preliminary metallization is then protected during the subsequent separation process.
Solution Approach 2:
The patent introduces a protective masking layer as an intermediary between the metallization deposition and the separation processes. This masking layer prevents metal from depositing into the dicing grooves during the metallization process. After metallization is complete, the masking layer is removed, revealing clean separation grooves without metal contamination. The intermediary masking layer enables both high productivity and manufacturing precision.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This approach effectively separates dies without causing chipping or cracking, enabling reliable electrical functionality and efficient packaging by preventing metal deposition into dicing grooves.
Implementation Method 1
using techniques like plasma etching and electrochemical deposition
Implementation Method 2
using techniques like plasma etching and electrochemical deposition
Data Source
AI summary
A method for separating a plurality of dies is provided. The method may include: selectively removing one or more portions from a carrier including a plurality of dies, for separating the plurality of dies along the selectively removed one or more portions, wherein the one or more portions are located between the dies; and subsequently forming over a back side of the dies, at least one metallization layer for packaging the dies