Wafer Coating with Sloped Stage for Laser Dicing
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Solution Overview
Problem
Conventional wafer dicing methods such as scribing and sawing result in chipping, cracking, and waste of wafer real estate due to jagged separation lines and residue issues from spin-coating, while plasma dicing faces cost and alignment challenges.
Innovation Solution
A hybrid method combining laser scribing and plasma etching with a spin-coating apparatus featuring a rotatable stage with a downward sloping region to minimize residue on the wafer frame, enabling precise positioning and reducing contamination.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional spin-coating techniques are used for mask application, then the wafer can be coated, but residue is deposited on the backside of the wafer causing misalignment during later processing operations
Solution Approach 1:
The patent extracts and removes the harmful residue generation mechanism by replacing conventional spin-coating with a droplet dispensing system that deposits material only on the front surface of the wafer, preventing backside contamination entirely
Solution Approach 2:
The patent introduces a carrier substrate as an intermediary between the droplet dispenser and the wafer, allowing precise controlled deposition of coating material while preventing direct contact and residue transfer to the wafer backside
2Ease of manufacture
If scribing is used for wafer dicing, then thin wafers can be separated, but chipping and cracking occur due to jagged separation lines
Solution Approach 1:
The patent merges laser scribing (which creates precise shallow grooves without mechanical contact) with plasma etching (which cleanly separates the wafer along the grooves), combining the advantages of both methods to eliminate chipping and cracking while maintaining dicing feasibility
Solution Approach 2:
The patent replaces the mechanical diamond scribe with a laser-based system that uses optical energy to create separation grooves, eliminating the mechanical contact that causes chipping and cracking in traditional scribing
3Ease of manufacture
If sawing is used for wafer dicing, then thick wafers can be separated, but wafer real estate is wasted due to required spacing between dies
Solution Approach 1:
The patent replaces the mechanical saw blade with a laser-based system that creates extremely narrow separation grooves, reducing the kerf width from hundreds of microns to micrometer scale, thereby maximizing the usable wafer area while maintaining dicing capability for thick wafers
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 hybrid method effectively reduces chipping and cracking, minimizes residue, and enhances wafer flatness for precise processing, allowing for more efficient and accurate dicing with reduced waste and improved throughput.
Implementation Method 1
A laser is used to ablate the photoresist mask and underlying materials
Implementation Method 2
plasma etching with a spin-coating apparatus
Implementation Method 3
spin-coating apparatus featuring a rotatable stage
Data Source
AI summary
Improved wafer coating processes, apparatuses, and systems are described. In one embodiment, an improved spin-coating process and system is used to form a mask for dicing a semiconductor wafer with a laser plasma dicing process. In one embodiment, a spin-coating apparatus for forming a film over a semiconductor wafer includes a rotatable stage configured to support the semiconductor wafer. The rotatable stage has a downward sloping region positioned beyond a perimeter of the semiconductor wafer. The apparatus includes a nozzle positioned above the rotatable stage and configured to dispense a liquid over the semiconductor wafer. The apparatus also includes a motor configured to rotate the rotatable stage.