Plasma Dicing Semiconductor Wafer with Electrostatic Chuck
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Solution Overview
Problem
Current plasma etching equipment is not compatible with substrates mounted on tape and supported in a frame for dicing, limiting the application of plasma dicing techniques, which require additional complex steps and are not fully compatible with standard dicing equipment.
Innovation Solution
A method for plasma dicing that includes a process chamber with a plasma source, a work piece support with an electrostatic chuck, and a cover ring for temperature control, allowing substrates to be mounted on a carrier support and processed using standard dicing techniques, enabling efficient separation of semiconductor substrates into individual die.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If plasma etching equipment is used for substrate processing, then high etch rates and cost-effective manufacturing are achieved, but the equipment is not compatible with substrates mounted on tape and supported in a frame for dicing
Solution Approach 1:
The chamber wall is segmented to include a movable window portion that can be opened or removed, allowing the plasma source to be positioned adjacent to the window for direct plasma generation near the workpiece. This segmentation enables the plasma etching equipment to accommodate substrates in non-traditional configurations such as those mounted on tape and supported in a frame.
Solution Approach 2:
The plasma source is positioned in a different spatial dimension - adjacent to the chamber wall rather than above the substrate. This lateral positioning allows plasma to be generated close to the workpiece without requiring the substrate to be in a traditional wafer holder configuration, enabling compatibility with dicing equipment setups.
2Ease of manufacture
If mechanical dicing techniques are used, then substrate separation is achieved, but chipping and breakage increase and kerf area loss exceeds 100 microns
Solution Approach 1:
The mechanical dicing system (diamond saw or breaking mechanism) is replaced with a plasma etching system. The plasma chemically removes material through a photoresist mask pattern, eliminating mechanical contact that causes chipping and breakage. This substitution achieves precise die separation with intact edges and minimal kerf loss.
Solution Approach 2:
The dicing process transitions from mechanical force application to controlled plasma chemistry parameters. By adjusting plasma power, gas flow rates, and exposure time, precise material removal is achieved without mechanical stress, eliminating chipping and reducing kerf width to minimal dimensions.
3Ease of manufacture
If laser dicing is used, then substrate separation is achieved, but residual material remains on die surface and stress is induced in the die
Solution Approach 1:
The laser dicing process is replaced with plasma etching. Instead of laser ablation that leaves residual material and induces thermal stress, the plasma process chemically removes material through controlled reactions with the substrate, leaving clean surfaces without stress induction.
Solution Approach 2:
The plasma process occurs in a controlled atmosphere of inert or reactive gases (such as fluorocarbon or chlorine-based gases) that enable clean material removal without the thermal effects of laser processing. This inert/controlled environment prevents residual material formation and thermal stress induction.
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 method allows for efficient plasma dicing of semiconductor substrates with reduced breakage and kerf dimensions, compatible with standard dicing equipment, and adaptable for various substrate materials, enhancing productivity and reducing residual material and stress on die surfaces.
Implementation Method 1
An electrostatic chuck may be incorporated into the work piece support whereby the electrostatic chuck clamps the substrate to the electrostatic chuck
Implementation Method 2
A plasma is generated through the plasma source whereby the work piece is etched through the generated plasma
Implementation Method 3
The work piece is exposed to a first plasma etch process using a first etchant gas within the plasma processing chamber
Implementation Method 4
The temperature of the cover ring can be controlled during the plasma etching step. During the plasma etching step, the cover ring can be cooled to a temperature of less than 80°C
Implementation Method 5
A cooling gas (typically Helium) is maintained between the substrate and the support to provide a thermal conductance path for heat removal
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 cover ring disposed above the work piece; generating a plasma through the plasma source; and etching the work piece through the generated plasma.