Plasma Dicing Semiconductor Wafer Electrostatic Clamping
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Solution Overview
Problem
Current plasma etching technologies for semiconductor substrates are not compatible with standard wafer dicing techniques, particularly for substrates mounted on tape and supported in a frame, limiting the adoption of plasma dicing methods that could reduce breakage and increase productivity.
Innovation Solution
A plasma processing apparatus that uses a vacuum chamber with a high-density plasma source, an electrostatic chuck, and a mechanical partition to etch semiconductor substrates mounted on tape and a frame, allowing for efficient separation of die while protecting the frame and tape from damage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If plasma etching is used to dice semiconductor substrates mounted on tape and frame, then breakage is reduced and productivity is increased, but standard plasma etching equipment is incompatible with such mounted substrates
Solution Approach 1:
The substrate processing is segmented into distinct zones: a first region for plasma etching and a second region for support. The frame and tape structure is segmented to provide support in the second region while allowing plasma access to the first region, enabling compatibility between plasma etching and mounted substrates
Solution Approach 2:
The frame and tape act as intermediary structures that mediate between the plasma etching process and the mounted substrate. They provide mechanical support and thermal management while being positioned to allow plasma species to reach the substrate surface for etching
2Force
If mechanical clamping is used to hold the substrate, then clamping force is provided, but contamination occurs due to contact between clamp and substrate
Solution Approach 1:
The mechanical clamping system is replaced with an electrostatic clamping system. The electrostatic chuck generates electrostatic forces to hold the substrate without mechanical contact, eliminating contamination from clamp-substrate contact while providing sufficient clamping force
3Object-generated harmful factors
If electrostatic chuck is used to provide clamping force, then contamination is avoided, but work piece bowing occurs due to pressurized fluid force on the back of the work piece
Solution Approach 1:
The frame and tape structure provides localized support in the second region, creating different mechanical properties in different zones. The support is positioned to counteract bowing forces while maintaining electrostatic clamping contact with the substrate surface
4Productivity
If standard plasma etching is used, then high etch rates are achieved, but the frame and tape are damaged by reactive gas plasma
Solution Approach 1:
The processing area is segmented into a first region for plasma etching where high etch rates are achieved, and a second region where the frame and tape are positioned to receive support and protection, reducing their exposure to damaging plasma species while maintaining overall process efficiency
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 reduces breakage and kerf dimensions, increases processing efficiency for thinner wafers, and enables non-rectilinear die formats, improving the cost-effectiveness and productivity of semiconductor dicing.
Implementation Method 1
The work piece is clamped to the work piece support. In one embodiment, the work piece is electrostatically clamped to the work piece support
Implementation Method 2
The work piece is exposed to plasma which etches the work piece
Implementation Method 3
plasma etching to separate the wafer into individual die
Implementation Method 4
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
Data Source
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.