Wafer Dicing Plasma Etching Scribe Line Test Structure Removal
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current wafer dicing techniques, such as mechanical and laser dicing, face challenges with small scribe line widths, increased dicing time, and damage to die regions due to mechanical stress and thermal effects, while plasma dicing improves surface quality but struggles with removing complex multilayer structures in the scribe line.
Innovation Solution
A method employing multiple etching cycles with alternating etching processes to remove complex test structures and dielectric layers, resulting in a flat sidewall and increased die strength, using plasma etching to expose the substrate and separate dies efficiently.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If mechanical dicing or laser dicing is used to cut the wafer, then the dicing process can be completed, but the die region adjacent to the scribe line may be damaged when the width of the scribe line is small
Solution Approach 1:
The patent replaces mechanical dicing tools with plasma etching technology. The plasma etching system uses reactive ions to chemically etch the scribe line material, eliminating mechanical contact with the die regions. This substitution allows for precise cutting along narrow scribe lines without the mechanical stress and chipping issues that plague traditional blade-based methods.
Solution Approach 2:
The patent changes the cutting mechanism from mechanical force to plasma-based chemical etching. By controlling plasma parameters such as power, gas flow, and etch chemistry, the process can selectively remove scribe line material while preserving adjacent die regions. The plasma process parameters are tuned to achieve anisotropic etching that follows the scribe line pattern precisely without lateral erosion into die areas.
2Ease of manufacture
If laser dicing or mechanical dicing is used to cut the wafer, then the dicing can be performed, but the time required to cut the wafer is greatly extended as the path length of the scribe line increases
Solution Approach 1:
The patent replaces slow mechanical dicing processes with plasma etching, which operates at higher speeds. The plasma process can etch through the scribe line material more rapidly than mechanical blades can physically cut, especially over long scribe line paths. The parallel nature of plasma exposure across the wafer surface also contributes to faster processing compared to sequential mechanical cutting.
3Ease of manufacture
If mechanical dicing is used to cut the wafer, then the dicing process can be completed, but there may be an issue of wafer chipping or cracking due to the mechanical stress generated by the dicing tool
Solution Approach 1:
The patent eliminates mechanical stress entirely by replacing the mechanical dicing blade with a plasma etching process. The plasma uses reactive species to chemically remove material through the scribe line without applying physical force to the wafer. This prevents the generation of mechanical stress that would otherwise cause chipping or cracking, particularly at stress concentration points on die sidewalls.
4Ease of manufacture
If laser dicing is used to cut the wafer, then the dicing process can be completed, but the thermal effect of the laser may be transmitted to the die region to adversely affect the die
Solution Approach 1:
The patent replaces laser-based thermal cutting with plasma etching. The plasma process uses reactive ion chemistry rather than thermal energy to remove material. This substitution eliminates the thermal effects that would otherwise conduct heat into adjacent die regions and cause damage. The plasma process is inherently more selective and localized to the exposed scribe line areas.
5Manufacturing precision
If plasma dicing is used to dice the wafer, then the sidewalls of the die have a flat surface, but the scribe line includes a complex structure of multilayers of metal features and insulating features that are difficult to remove
Solution Approach 1:
The patent segments the etching process into multiple sequential steps, each targeting specific layers of the complex scribe line structure. The process removes metal features and insulating features in separate etching cycles, allowing optimization of etch chemistry and parameters for each material type. This segmented approach makes the complex multilayer removal process manageable and selective.
Solution Approach 2:
The patent changes plasma process parameters between etching steps to selectively remove different materials. By adjusting gas composition, power, pressure, and other parameters, the process achieves selective etching of metal layers followed by insulating layers. This parameter modulation allows the plasma process to handle the complex multilayer scribe line structure while maintaining clean, flat sidewalls on the resulting die.
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 method effectively removes complex structures in the scribe region, producing dies with flat sidewalls that can withstand greater stress, reducing the risk of cracking and improving dicing efficiency by using plasma etching cycles to control the etching process and maintain smooth progression.
Implementation Method 1
The first removal process includes performing a plurality of etching cycles, and each etching cycle includes performing a first etching process to remove a portion of the test structure and performing a second etching process to remove a portion of the dielectric layer
Data Source
AI summary
A method of wafer dicing and a die are provided. The method includes the following processes. A wafer is provided, the wafer includes a plurality of die regions and a scribe region between the die regions. The scribe region includes a substrate, and a dielectric layer and a test structure on the substrate, the test structure is disposed in the dielectric layer. A first removal process is performed to remove the test structure and the dielectric layer around the test structure, so as to expose the substrate. The first removal process includes performing a plurality of etching cycles, and each etching cycle includes performing a first etching process to remove a portion of the test structure and performing a second etching process to remove a portion of the dielectric layer. A second removal process is performed to remove the substrate in the scribe region, so as to form a plurality of dies separated from each other.