Wafer Laser Beam Branching for Fast, Low-Chip Dicing
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Solution Overview
Problem
Mechanical cutting of semiconductor substrates for separating integrated circuits into chips often results in defects such as chipping, and existing laser cutting methods may not optimize productivity effectively.
Innovation Solution
An apparatus for wafer processing that utilizes a stage movable in a first direction, with multiple optical systems and actuators to form parallel beam regions on the wafer using laser beams, allowing for precise etching along scribe lines to separate integrated circuit regions, enhancing productivity and reducing defects.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If mechanical cutting is used to separate integrated circuits into semiconductor chips, then the cutting process is simple and fast, but defects such as chipping occur frequently
Solution Approach 1:
The patent replaces the mechanical cutting system with a laser-based optical system. Multiple optical systems generate laser beams that are focused onto the wafer to perform cutting without mechanical contact, thereby eliminating chipping defects while maintaining cutting efficiency through parallel processing of multiple beams
2Device complexity
If a single laser beam is used for etching, then the optical system is simple, but the etching time is long and productivity is low
Solution Approach 1:
The patent divides a single laser beam into multiple separate laser beams using optical systems. Each optical system processes one or more laser beams independently, allowing parallel etching of multiple scribe lines simultaneously. This segmentation of the beam enables faster processing while keeping each individual optical system relatively simple
Solution Approach 2:
The patent combines multiple optical systems to work together in parallel, each contributing to the overall etching process. By merging the capabilities of multiple optical systems, the apparatus achieves high-speed parallel processing of multiple beam regions on the wafer, significantly improving productivity
3Productivity
If multiple optical systems are used to form parallel beam regions, then etching speed increases, but the distance control between beams becomes more difficult
Solution Approach 1:
The patent employs actuators that can dynamically adjust the positions of optical systems in real-time. This dynamic adjustment capability allows the apparatus to maintain precise spacing between multiple laser beams despite variations in the wafer surface or positioning, ensuring accurate beam spacing while maintaining high etching speed
Solution Approach 2:
The patent incorporates sensors that detect the actual positions of optical systems and provide feedback to the control system. This feedback mechanism enables closed-loop control of beam spacing, allowing the system to compensate for positioning errors and maintain precise beam separation distances throughout the etching process
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
The apparatus improves productivity by reducing the time required for etching and ensures reliable optical characteristics, minimizing defects in semiconductor chips.
Implementation Method 1
a laser light source that generates a laser beam
Implementation Method 2
a plurality of optical systems that generate a plurality of branch beams based on the laser beam, the plurality of optical systems including a first optical system that generates (1_1)th and (1_2)th branch beams of the plurality of branch beams, the (1_1)th and (1_2)th branch beams being branched in a second direction
Data Source
AI summary
An apparatus for wafer processing includes a stage supporting a wafer and movable in a first direction parallel with an upper surface of the wafer; a laser light source generating a laser beam; a first optical system generating branch beams spaced apart from each other by a first distance in a second direction parallel with the upper surface and crossing the first direction, by branching the laser beam in the second direction; a second optical system generating a plurality of second branch beams spaced apart from each other in the first direction by branching the laser beam in the first direction; and an actuator adjusting the first distance. The first and second optical systems simultaneously form first and second beam regions spaced apart from each other by the first distance on the wafer in a direction parallel with the first direction as the stage moves in the first direction.