Laser Wafer Modification Layers for Low-Force Separation
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Solution Overview
Problem
Existing methods require excessive tensile force to separate wafers due to connected cracks from internal modification layers, leading to inefficiencies in thinning processing.
Innovation Solution
A wafer processing system with a modifying apparatus that forms controlled modification layers, including peripheral and internal layers, to facilitate separation by reducing bonding strength and forming non-bonding regions, enabling efficient thinning and edge trimming.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If internal modification layers are formed with connected cracks, then wafer separation is facilitated, but excessive tensile force is required leading to processing inefficiency
Solution Approach 1:
The patent divides the modification layers into two distinct types: first modification layers with spaced-apart cracks that maintain structural integrity, and second modification layers with connected cracks that enable separation. This segmentation allows the system to achieve both easy separation and processing efficiency by using different crack patterns in different regions of the wafer stack.
Solution Approach 2:
The patent applies different crack characteristics to different locations within the wafer structure. The first modification layers (with spaced cracks) are positioned in regions where structural integrity is needed during processing, while the second modification layers (with connected cracks) are positioned in regions where separation is desired. This local differentiation resolves the contradiction between maintaining integrity and enabling separation.
2Productivity
If modification layers are formed to reduce bonding strength, then thinning processing is improved, but wafer structural integrity may be compromised
Solution Approach 1:
The patent segments the modification layers into two functional types with different crack patterns. The first modification layers maintain structural integrity through spaced cracks, while the second modification layers enable thinning through connected cracks. This segmentation allows simultaneous achievement of both structural integrity and thinning efficiency.
Solution Approach 2:
Different crack densities and connectivity patterns are applied locally within the modification layers. Regions requiring structural support have spaced cracks, while regions requiring thinning have connected cracks. This local quality differentiation enables the wafer to maintain integrity in critical areas while allowing efficient thinning in appropriate regions.
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 system allows for appropriate thinning and edge trimming of wafers with reduced bonding strength, minimizing the need for excessive force and improving processing efficiency.
Implementation Method 1
a modifying device configured to radiate laser light to an inside of the processing target object to form multiple modification layers along a plane direction
Implementation Method 2
the internal modification layer is formed by changing a single crystalline structure of the substrate into a polycrystalline structure while radiating laser light to an inside of the substrate
Data Source
AI summary
A processing apparatus configured to process a processing target object includes a modifying device configured to radiate laser light to an inside of the processing target object to form multiple modification layers along a plane direction; and a controller configured to control an operation of the modifying device at least. The controller controls the modifying device to form, in the forming of the modification layers, a first modification layer formation region in which cracks that develop from neighboring modification layers along the plane direction are not connected, and also controls the modifying device to form, in the forming of the modification layers, a second modification layer formation region in which cracks that develop from neighboring modification layers along the plane direction are connected.