Partial Backside Metal Groove for Semiconductor Die Singulation
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Solution Overview
Problem
Current die singulation methods for semiconductor devices often result in damage to the substrate and inefficiencies due to the need for flipping and handling, as well as issues with re-deposition of backside metal, which can reduce yield and reliability.
Innovation Solution
A partial backside metal removal method involving forming a groove in the backside metal layer, using laser or saw blades, and plasma etching to singulate die without fully penetrating the substrate, with active monitoring and real-time adjustments to prevent damage and optimize the process.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If current die singulation methods are used, then die can be separated from substrate, but substrate damage occurs and handling complexity increases
Solution Approach 1:
A groove is formed in the backside metal layer before the actual singulation process. This preliminary action creates a controlled pathway that guides the singulation cut, preventing uncontrolled substrate damage while maintaining efficient die separation
Solution Approach 2:
The backside metal layer serves as an intermediary layer between the substrate and the singulation process. By forming a groove in this intermediate layer first, the system creates a controlled interface that reduces direct mechanical stress on the substrate during singulation, thereby minimizing substrate damage
2Ease of manufacture
If backside metal layer is fully removed, then singulation can be completed, but re-deposition of metal occurs reducing yield
Solution Approach 1:
Instead of completely removing the backside metal layer, the method applies partial removal by forming a groove only to a specific depth. This partial action is sufficient to enable complete singulation while preventing excessive metal removal that would cause re-deposition and yield loss
Solution Approach 2:
The groove formation applies localized removal of the backside metal layer only in the regions where singulation is needed, rather than uniform removal across the entire layer. This local quality approach maintains metal integrity in areas where it is still needed while enabling singulation elsewhere
3Ease of operation
If substrate is thinned, then backside access is improved, but substrate strength decreases
Solution Approach 1:
The groove is formed in the backside metal layer before thinning the substrate. This preliminary structuring of the metal layer provides mechanical support and guidance during subsequent substrate thinning, allowing better backside access while maintaining substrate integrity through the structured metal framework
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 method reduces substrate handling, minimizes damage, and increases yield by allowing singulation from the backside, reducing re-deposition of backside metal and improving the reliability of semiconductor packages with smoother sidewalls through remote plasma healing.
Implementation Method 1
forming a groove only partially through a thickness of the backside metal layer
Implementation Method 2
Removing the backmetal material in the die street and removing substrate material in the die street/scribe grid/saw street
Implementation Method 3
removing substrate material in the die street through plasma etching from the first side of the die
Implementation Method 4
removing a remaining material of the thickness of the backmetal in the die street through jet ablation
Implementation Method 5
remote plasma healing a sidewall of the die
Data Source
AI summary
Implementations of methods of singulating a plurality of die included in a substrate may include forming a plurality of die on a first side of a substrate, forming a backside metal layer on a second side of a substrate, forming a groove only partially through a thickness of the backside metal layer, and singulating the plurality of die included in the substrate through removing backmetal material in the die street and removing substrate material in the die street. The groove may be located in a die street of the substrate.