Stationary Actively-Cooled Shadow Ring for Plasma Chamber Heat Dissipation
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Solution Overview
Problem
Current methods for dicing semiconductor wafers, such as scribing and sawing, result in chipping, cracking, and waste of wafer real estate due to jagged separation lines and the need for significant spacing between dies, while plasma dicing is limited by cost and production issues with metals like copper.
Innovation Solution
A hybrid method combining femtosecond-based laser scribing and plasma etching, with a stationary actively-cooled shadow ring for temperature control and protection, to singulate integrated circuits with minimal heat damage and precise control, allowing for denser packing and reduced waste.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If scribing or sawing is used for wafer dicing, then the wafer can be separated into individual dies, but chipping and cracking occur along the severed edges and additional spacing is required between dies
Solution Approach 1:
The patent replaces mechanical dicing methods (scribing and sawing) with a plasma-based process. The plasma process uses ionized gas to etch and separate the wafer material without mechanical contact, thereby eliminating the chipping and cracking that occur with diamond-tipped scribes and saw blades. This substitution of mechanical energy with plasma energy directly resolves the contradiction between achieving wafer separation and maintaining edge quality.
2Reliability
If additional spacing is required between dies to prevent damage, then chipping and cracking are reduced, but wafer real estate is wasted and fewer dies can be formed
Solution Approach 1:
By replacing mechanical dicing with plasma processing, the patent achieves clean separations without chipping or cracking, allowing dies to be placed closer together without risking edge damage. This eliminates the need for excessive spacing between dies, thereby maximizing the usable wafer area and increasing the number of dies per wafer while maintaining reliability.
3Productivity
If a diamond saw is used for cutting, then thick wafers can be diced, but the blade thickness requires three to five hundred microns separation and substantial cleaning is needed
Solution Approach 1:
The patent substitutes the mechanical sawing process with plasma etching. The plasma process uses reactive ions to remove material through chemical reactions rather than mechanical abrasion. This results in cleaner cuts with minimal debris generation, eliminating the substantial cleaning operations required after sawing while maintaining the capability to dice thick wafers.
4Ease of manufacture
If plasma dicing is implemented, then cost and production issues with metals like copper are avoided, but the process may still generate heat affecting the substrate
Solution Approach 1:
The patent introduces a cooled substrate holder as an intermediary component between the plasma source and the wafer. The substrate holder is equipped with cooling channels that circulate coolant to actively remove heat from the wafer during plasma processing. This mediator prevents excessive heat accumulation in the substrate while allowing the plasma dicing process to proceed, resolving the contradiction between cost effectiveness and temperature control.
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 minimizes chipping and cracking, enables denser packing of integrated circuits on the wafer, and reduces waste by providing a clean separation method that is cost-effective and independent of crystal structure orientation.
Implementation Method 1
a cooling fluid is transported through the cooling channel of the shadow ring during the plasma etching
Implementation Method 2
a cooling fluid is transported through the cooling channel of the shadow ring during the plasma etching
Implementation Method 3
plasma etching the substrate through the streets to singulate the integrated circuits
Implementation Method 4
The shadow ring shields the substrate carrier from the plasma etching
Data Source
AI summary
Methods of and apparatuses for dicing semiconductor wafers, each wafer having a plurality of integrated circuits, are described. In an example, a plasma processing apparatus includes a processing chamber having a chamber wall. The plasma processing apparatus also includes a plasma source in an upper portion of the processing chamber. A sample support is included for situating a sample below the plasma source. An actively-cooled shadow ring having a cooling channel therein for cooling fluid transport is fixedly attached to the chamber wall of the processing chamber, between the plasma source and the sample support.