Semiconductor Die Singulation via Plasma Etching and Fluid Machining
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Solution Overview
Problem
The semiconductor industry faces challenges in efficiently singulating die from wafers due to non-compatibility of plasma dicing with wafer backside layers, which hinders subsequent processing and reduces manufacturing throughput.
Innovation Solution
A method involving plasma etching to form narrow singulation lines and subsequent fluid machining to remove backside layers within these lines, using a pressurized fluid to minimize damage and contamination, allowing for efficient separation and reclaim of die.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If plasma dicing is used to singulate die, then throughput and scribe line width are improved, but backside layers cannot be effectively removed from singulation lines
Solution Approach 1:
The singulation process is divided into two distinct stages: first, plasma dicing creates narrow singulation lines to improve throughput; second, a separate mechanical removal process (such as fluid jet machining or precision milling) removes the backside layers from within the singulation lines. This segmentation allows each process to be optimized independently, resolving the contradiction between throughput improvement and manufacturability.
Solution Approach 2:
The patent introduces an intermediary removal process that acts as a bridge between plasma dicing and subsequent assembly operations. This intermediary step effectively eliminates the backside layer material that remains after plasma dicing, enabling successful pick-and-place and assembly processes while preserving the throughput benefits of narrow plasma-cut singulation lines.
2Ease of manufacture
If conventional scribing with diamond cutting wheel is used, then backside layers can be removed, but scribe line width is large and throughput is reduced
Solution Approach 1:
The patent replaces the conventional mechanical diamond cutting wheel with a plasma-based dicing system. This substitution eliminates the need for wide scribe lines required by mechanical cutting, enabling narrow singulation lines that improve die density and throughput. The plasma process inherently removes material without the mechanical constraints of wheel width, simultaneously achieving both narrow lines and effective backside layer removal.
3Productivity
If narrow scribe lines are used to increase die density, then manufacturing capacity is improved, but backside layers remain in singulation lines hindering subsequent processing
Solution Approach 1:
The patent applies preliminary plasma dicing to create narrow singulation lines before final die release. This preliminary action establishes the singulation geometry needed for high die density while leaving the backside layers in place temporarily. A subsequent removal step then clears these layers, ensuring that narrow lines do not impede subsequent pick-and-place and assembly operations.
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 enables cost-effective and efficient separation of die with minimal damage, supporting flexible pattern singulation and facilitating subsequent processing steps like pick-and-place, thereby improving manufacturing capacity.
Implementation Method 1
Other methods, which have included thermal laser separation (TLS), stealth dicing (laser dicing from the backside of the wafer), and plasma dicing, have been explored as alternatives to scribing.
Implementation Method 2
separating portions of the layer of material within the singulation lines using a pressurized fluid
Data Source
AI summary
In one embodiment, semiconductor die are singulated from a semiconductor wafer having a backmetal layer by placing the semiconductor wafer onto a carrier tape with the backmetal layer adjacent the carrier tape, forming singulation lines through the semiconductor wafer to expose the backmetal layer within the singulation lines, and separating portions of the backmetal layer using a fluid.