Vacuum Chuck Cleaning via Sonic Jet Hover Assembly
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
The porous ceramic grind chuck in semiconductor wafer grinding machines clogs with small particles from swarf, leading to reduced chuck life and non-uniform wafer edges due to inadequate cleaning, particularly at the perimeter where dimensional differences cause vacuum inefficiency.
Innovation Solution
A vacuum cleaner assembly with a fluid source and sonic energy is positioned adjacent the work chuck to manually or automatically remove particles from the top surface, ensuring vacuum flow and preventing clogging, utilizing a gimbal mechanism to hover above the chuck surface without contact and a movable arm for precise positioning.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the porous chuck is used to hold the wafer during grinding, then the wafer can be securely positioned, but the porous material becomes clogged with swarf particles over time reducing vacuum flow
Solution Approach 1:
The cleaning system performs preliminary actions by removing swarf particles from the porous chuck surface before they can deeply clog the pores. The high-velocity jet stream pre-cleans the surface area, while the vacuum cleaner subsequently removes particles from within the porous material, preventing cumulative clogging that would reduce vacuum flow and chuck service life.
Solution Approach 2:
The invention introduces a two-stage cleaning intermediary system between the grinding process and the chuck. The jet stream acts as an intermediary to blast away surface particles, while the vacuum cleaner with HEPA filter serves as an intermediary to capture and remove particles from the porous structure, protecting the chuck from direct contamination by swarf.
2Manufacturing precision
If the porous chuck edge becomes clogged with particles, then vacuum flow is reduced, but this causes the wafer edge to rise and be over-grinded
Solution Approach 1:
The cleaning system applies local quality by targeting specific areas of the porous chuck. The jet stream is directed at the perimeter area where wafer contact occurs, concentrating cleaning energy where swarf accumulation most affects wafer edge uniformity. The vacuum cleaner similarly focuses on removing particles from the porous material at the chuck perimeter to maintain localized vacuum flow consistency.
3Ease of manufacture
If manual cleaning of the porous chuck is performed, then particle removal is possible, but the cleaning process is time-consuming and labor-intensive
Solution Approach 1:
The invention replaces manual mechanical cleaning with an automated system combining jet stream technology and vacuum extraction. The jet stream automatically blasts particles from the porous surface at high velocity, while the vacuum cleaner simultaneously extracts particles from within the porous material, eliminating the need for manual disassembly, soaking, and brushing operations.
Solution Approach 2:
The cleaning system utilizes pneumatic and hydraulic principles through the jet stream mechanism. Compressed gas or liquid is directed through a nozzle to create a high-velocity jet that impacts and dislodges swarf particles from the porous chuck surface and within its structure, providing automated, rapid cleaning without manual intervention.
4Productivity
If the vacuum cleaner assembly contacts the chuck surface directly, then cleaning effectiveness increases, but the risk of damage to the porous surface increases
Solution Approach 1:
The vacuum cleaner assembly uses an intermediary approach by combining a protective shroud with a jet stream mechanism. The shroud positions the cleaning elements close to the chuck surface without direct contact, while the jet stream acts as an intermediary medium to transmit cleaning energy to the porous material, achieving effective particle removal while protecting the delicate chuck surface from mechanical damage.
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 solution effectively maintains the chuck surface clean, preventing wafer edge lifting and non-uniform thickness, extending chuck life by ensuring consistent vacuum flow and removing swarf particles, thus preventing wafer star cracks and edge over-grinding.
Implementation Method 1
a fluid source which, when activated, directs fluid to the chuck surface which in turn causes the assembly to hover above the work chuck surface
Implementation Method 2
a vacuum device for pulling particles, or swarf, from the top surface of the chuck
Implementation Method 3
A source of sonic energy may be positioned in the fluid path, the sonic energy loosening particles that may be tightly adhering to the chuck surface
Data Source
AI summary
A vacuum assembly for removing debris formed on the surface of a work chuck after a wafer grinding process by positioning a vacuum source above the work chuck and then activating the vacuum source.