Wafer Laser Beam Width Control for Street-Constrained Processing
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Solution Overview
Problem
Conventional laser processing devices face challenges in confining laser light within the street region between functional elements on a semiconductor wafer without being blocked by structures, leading to reduced laser emission and potential degradation of processing quality.
Innovation Solution
A laser processing device with a beam width adjusting unit, controlled by surface information, ensures the laser beam width is equal to or less than the street width, preventing blocking by structures and maintaining efficient emission.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the laser light is confined within the street by controlling beam width with a slit, then the laser light is prevented from reaching functional elements, but the laser light may be blocked by structures with height, reducing desired laser emission
Solution Approach 1:
The patent applies dynamics by making the beam width adjustable rather than fixed. The beam width adjusting unit dynamically changes the beam width based on the specific street width and structure height information, allowing the system to adapt to different geometries and avoid blocking while maintaining confinement.
Solution Approach 2:
The patent changes the beam width parameter according to the specific geometric conditions of each street and structure. By adjusting the beam width parameter based on measured street width and structure height, the system optimizes laser emission efficiency while ensuring confinement and avoiding blocking.
2Productivity
If the beam width is reduced to fit within the street width, then the laser light avoids blocking by structures, but the processing quality may be degraded due to interference or insufficient energy
Solution Approach 1:
The patent optimizes the beam width parameter within the constraints of street width and structure height. By carefully selecting the beam width parameter, the system achieves both efficient emission and sufficient processing quality without interference or energy insufficiency.
Solution Approach 2:
The patent uses measured surface information including street width and structure height as feedback to determine the appropriate beam width. This feedback mechanism ensures that the beam width is optimized for each specific case, maintaining processing quality while avoiding blocking and interference.
3Ease of operation
If the laser light is emitted from the surface side with functional elements, then direct observation of modified regions is possible, but the laser light must be precisely confined to avoid damaging functional elements
Solution Approach 1:
The patent adjusts the beam width parameter based on the specific geometric conditions to simplify the confinement control. By optimizing the beam width parameter, the system achieves effective confinement without requiring overly complex control mechanisms, making the operation easier while maintaining 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 configuration allows for desired laser emission within the street region, preventing output reduction and processing quality degradation, while avoiding structural interference or melting.
Implementation Method 1
emitting laser light to the wafer from the first surface side to form one or more modified regions inside the wafer
Implementation Method 2
emitting laser light to the wafer from the first surface side to form one or more modified regions inside the wafer
Data Source
AI summary
A laser processing device includes: a stage that supports a wafer having a front surface, on which a plurality of functional elements are formed and a street region extends so as to pass between adjacent functional elements, and a back surface on a side opposite to the front surface; a light source that emits laser light to the wafer from the front surface side to form one or more modified regions inside the wafer; a spatial light modulator as a beam width adjusting unit; and a control unit that controls the spatial light modulator so that the beam width of the laser light is adjusted to be equal to or less than the width of the street region and a target beam width according to surface information including the position and height of a structure forming a functional element adjacent to the street region.