Stealth Dicing Substrate Separation with Laser Scribe Lines
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Solution Overview
Problem
Conventional singulation and packaging processes in device manufacturing, such as semiconductor and MEMS device manufacturing, face significant yield loss due to debris damage from saw dicing, which bombards bond pad areas with silicon debris, leading to electronic circuit damage.
Innovation Solution
A method involving stealth dicing with laser-irradiated scribe lines on stacked substrates, where the scribe lines are aligned back-to-front and offset, allowing for simultaneous separation of substrates using a single expansion of dicing tape, without completely penetrating the second substrate, and utilizing beveled dicing blades or angled sidewalls to form lids that cover devices and expose bond pads for capillary bonding.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If saw dicing is used for substrate separation, then singulation can be performed, but silicon debris damages bond pad areas leading to yield loss
Solution Approach 1:
The patent replaces the mechanical saw dicing system with a laser-based stealth dicing system. The laser creates scribe lines through the substrate without mechanical contact, eliminating silicon debris generation while maintaining singulation capability. This substitution of mechanical energy with optical energy directly resolves the contradiction between productivity and reliability.
Solution Approach 2:
The patent introduces dicing tape as an intermediary medium between the laser and the substrate. The tape absorbs the laser energy and transfers it to the substrate, enabling precise scribe line formation without direct laser-substrate contact. This intermediary facilitates the transition from mechanical to optical dicing while maintaining process control.
2Ease of manufacture
If conventional sequential singulation and packaging are used, then processes can be completed, but manufacturing time increases
Solution Approach 1:
The patent merges the singulation and packaging operations into a single integrated process. By performing both operations simultaneously on stacked substrates using the same laser system, the patent eliminates the sequential execution overhead and reduces total manufacturing cycle time while maintaining complete process functionality.
Solution Approach 2:
The patent enables continuous processing by maintaining laser operation throughout both singulation and packaging steps without interruption. The laser continuously writes scribe lines and forms lids in a single pass through the stacked substrates, eliminating idle time between operations and maximizing productive action duration.
3Productivity
If laser stealth dicing is used with offset scribe lines, then simultaneous separation of stacked substrates is achieved, but process complexity increases
Solution Approach 1:
The patent segments the singulation process by treating each substrate in the stack independently with offset scribe lines. Each substrate receives customized scribe patterns tailored to its specific packaging requirements, allowing simultaneous processing of multiple substrates with different singulation needs without increasing overall process complexity.
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 reduces yield loss by avoiding direct contact with saw blades, minimizing debris damage, and enabling efficient singulation of devices with angled lids that facilitate capillary bonding, while maintaining the integrity of electronic circuits.
Implementation Method 1
Scribing may use a laser irradiated on the substrate in a stealth dicing operation.
Implementation Method 2
The method may further include attaching a dicing tape to the first wafer, the dicing tape being expanded after the second scribe line is formed.
Data Source
AI summary
A method of singulating includes scribing a first scribe line on a first side of a substrate, scribing a second scribe line on a second side of the substrate, the first and second sides facing away from each other, the second scribe line being substantially parallel to the first scribe line, and simultaneously separating the substrate at the first scribe line and the second scribe line.