Plasma Dicing Electrostatic Chuck for Tape-Mounted Wafers
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Solution Overview
Problem
Current plasma etching equipment is not compatible with substrates mounted on tape and supported in a frame, and standard front side masking techniques, leading to non-uniformities and additional complex steps in the dicing process.
Innovation Solution
A plasma etching apparatus that uses a vacuum processing chamber with a high density plasma source, an electrostatic chuck, and a protective cover ring to maintain thermal control and minimize exposure of the frame and tape to the plasma, while allowing for standard front side masking and compatibility with established dicing techniques.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If plasma etching is used to dice semiconductor substrates, then etch rate and manufacturing efficiency are improved, but equipment compatibility with tape-mounted substrates and uniformity of etching are worsened
Solution Approach 1:
The substrate support system is segmented into separate functional components: the substrate mounted on tape, the frame providing structural support, and the electrostatic chuck providing localized clamping and thermal control. This segmentation allows each component to be optimized independently for its specific function while maintaining overall system compatibility with plasma etching processes
Solution Approach 2:
The electrostatic chuck acts as an intermediary between the plasma etching equipment and the tape-mounted substrate. It provides the necessary electrical connection for plasma generation while mechanically supporting the substrate through electrostatic forces rather than direct mechanical contact, thereby maintaining compatibility with both plasma processing and tape mounting
2Device complexity
If the frame and tape are exposed to plasma during etching, then processing simplicity is improved, but thermal control and integrity of the tape are worsened
Solution Approach 1:
The electrostatic chuck provides localized thermal control and clamping forces only at the substrate contact area, while leaving the frame and tape regions exposed or protected as appropriate. This local application of thermal management allows the substrate to be properly controlled during etching without subjecting the entire assembly to unnecessary thermal stress
Solution Approach 2:
The electrostatic chuck is extracted from direct mechanical contact with the substrate edges and frame structure, interacting only through electrostatic fields. This extraction prevents mechanical interference with the frame and tape while maintaining electrical connection for plasma generation, separating the functions of mechanical support and electrical coupling
3Ease of manufacture
If standard front side masking techniques are used, then ease of manufacture is improved, but plasma uniformity and etch quality are worsened due to non-uniform plasma distribution
Solution Approach 1:
The electrostatic chuck creates a uniform electric field distribution across the substrate surface by maintaining equipotential conditions during plasma generation. This uniform field distribution ensures consistent plasma density and chemistry across the entire substrate area, enabling uniform etching rates and high-quality etch profiles throughout the diced 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
Enables efficient and uniform plasma dicing of semiconductor substrates into individual die with reduced breakage and kerf dimensions, maintaining the integrity of the tape and frame, and compatibility with standard dicing equipment.
Implementation Method 1
an electrostatic chuck to which the substrate is clamped
Implementation Method 2
A pressurized fluid, typically a gas such as Helium is maintained between the substrate and the support to provide a thermal conductance path for heat transfer
Implementation Method 3
uses plasma etching to separate the wafer into individual die
Data Source
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AI summary
The present invention provides a method for plasma dicing a substrate. The method comprising providing a process chamber having a wall; providing a plasma source adjacent to the wall of the process chamber; providing a work piece support within the process chamber; placing the substrate onto a support film on a frame to form a work piece work piece; loading the work piece onto the work piece support; providing a clamping electrode for electrostatically clamping the work piece to the work piece support; providing a mechanical partition between the plasma source and the work piece; generating a plasma through the plasma source; and etching the work piece through the generated plasma.