Wafer Separation Apparatus Using Segmented Fluid Ejection
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Solution Overview
Problem
Existing processing apparatuses risk rupturing wafers due to pressure from ejected mixed fluids, while attempts to speed up separation, such as gradually increasing fluid ejection, result in prolonged processing times.
Innovation Solution
A processing apparatus with a chuck table, fluid communication passages, and regulating valves for water and air flow rates, controlled by a unit that uses water to space the wafer from the holding surface and then increases air flow to safely lift it without rupture.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If mixed fluid is ejected from the holding surface to separate the wafer, then the wafer can be separated from the holding surface, but the wafer tends to be ruptured by the pressure of the mixed fluid
Solution Approach 1:
The fluid ejection process is segmented into two distinct phases: first water is ejected to space the wafer from the holding surface, then air is ejected to lift the delivery unit. This segmentation allows each phase to perform its specific function optimally without causing damage.
Solution Approach 2:
Water is ejected first as a preliminary action to create spacing between the wafer and holding surface before air is introduced for lifting. This preliminary spacing prevents the wafer from being in direct contact with high-pressure air that could cause rupture.
2Reliability
If the amount of mixed fluid is gradually increased to avoid wafer rupture, then the wafer can be separated safely, but it takes time to separate the processed wafer from the holding surface
Solution Approach 1:
The separation process is divided into two sequential steps: water ejection for spacing and air ejection for lifting. This segmentation enables rapid separation by using water's lower pressure to create space quickly, then using air's higher pressure to complete the lifting without risking wafer damage.
Solution Approach 2:
Water is ejected as a preliminary action to create spacing before air is introduced. This preliminary spacing allows the subsequent air ejection to occur at higher flow rates without directly impacting the wafer, thus reducing overall separation time while maintaining safety.
3Speed
If high pressure mixed fluid is used to quickly separate the wafer, then separation speed increases, but the wafer is ruptured by the pressure
Solution Approach 1:
The fluid ejection is segmented into water first (lower pressure) for spacing, then air (higher pressure) for lifting. This segmentation allows high separation speed through the air phase while the water phase prevents direct high-pressure contact with the wafer, avoiding damage.
Solution Approach 2:
Water acts as an intermediary substance between the high-pressure air system and the wafer. By ejecting water first to create spacing, it mediates the interaction between the subsequent high-pressure air ejection and the wafer, preventing direct high-pressure contact that would cause rupture.
Data Source
AI summary
A wafer held on a delivery pad is lifted from a holding surface, and when a lower surface of the wafer has been spaced in its entirety from the holding surface, an air flow rate regulating valve is opened to eject air from the holding surface. As the distance between the holding surface and the wafer spaced from the holding surface increases by lifting of a delivery unit, the degree of opening of the air flow rate regulating valve is adjusted to increase a flow rate of air from the holding surface, thereby spacing the wafer from the holding surface in a short period of time without rupturing the wafer.