Supercritical Drying Apparatus with Segmented Thermal Control
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Solution Overview
Problem
The challenge in semiconductor device fabrication is pattern collapse during liquid drying on substrates, where uneven drying leads to projection portion collapse due to surface tension imbalances, and existing supercritical drying methods require temperature control that prolongs processing time and reduces device throughput and heater maintenance intervals.
Innovation Solution
A supercritical processing apparatus with a heat-transfer suppressing mechanism, such as a cooling mechanism, to prevent liquid evaporation on the substrate until the processing fluid is supplied, using a heating unit to maintain the processing fluid in a supercritical state while minimizing heat transfer to the substrate, thereby preventing pattern collapse and improving throughput.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If the heater is turned off to prevent liquid evaporation and pattern collapse, then pattern collapse is prevented, but the time required for heating the fluid increases and throughput is reduced
Solution Approach 1:
The heating system is divided into two independent heating units: a first heating unit that heats the processing fluid in the processing chamber, and a second heating unit that heats the seating unit. This segmentation allows independent control of heating zones, enabling the processing fluid to be heated while the substrate remains at a temperature that prevents liquid evaporation and pattern collapse.
Solution Approach 2:
Different thermal conditions are applied to different locations: the processing fluid is heated to supercritical temperature and pressure, while the substrate seating area is maintained at a lower temperature. This local quality differentiation allows the fluid to achieve supercritical state for effective drying while the substrate avoids excessive heat that would cause pattern collapse.
2Manufacturing precision
If the heater is turned off during substrate loading, then pattern collapse is prevented, but the heater switch deteriorates faster and maintenance interval is shortened
Solution Approach 1:
The heating system is segmented into two independent units, allowing the first heating unit to remain on and heat the processing fluid while the second heating unit controls the substrate temperature. This eliminates the need to turn off the entire heating system, reducing switch operations and extending heater reliability.
Solution Approach 2:
The processing fluid is pre-heated to supercritical state before substrate loading, and the seating unit is prepared with appropriate temperature control. This preliminary preparation allows the substrate to be loaded and processed without requiring heater shutdown, thereby preventing switch deterioration and extending maintenance intervals.
3Productivity
If the substrate is heated to obtain supercritical fluid, then supercritical drying is achieved, but the liquid evaporates from the substrate and pattern collapse occurs
Solution Approach 1:
The heating function is segmented between two independent units: the first heating unit heats the processing fluid to supercritical state for effective drying, while the second heating unit maintains the substrate at a controlled temperature that prevents liquid evaporation and pattern collapse. This segmentation resolves the contradiction between achieving supercritical drying and preventing pattern collapse.
Solution Approach 2:
Different thermal conditions are applied locally: the processing fluid receives high temperature heating to achieve supercritical state, while the substrate seating area maintains moderate temperature to prevent pattern collapse. This local quality differentiation enables both supercritical drying efficiency and pattern integrity.
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 solution effectively suppresses pattern collapse, enhances processing efficiency by reducing the need for frequent heater state changes, and prolongs the maintenance interval of heater components.
Implementation Method 1
a heating unit to heat the processing fluid supplied into the processing receptacle so as to place the processing fluid in a supercritical state
Implementation Method 2
a heat-transfer suppressing mechanism to suppress heat transfer from the heating unit to the substrate so as to prevent the liquid from evaporating from the substrate
Data Source
AI summary
Disclosed is a supercritical processing apparatus which can suppress the occurrence of pattern collapse, improve the throughput, and prolong a maintenance interval. In the disclosed supercritical processing apparatus to remove a liquid remained on a substrate by a super-critical state processing fluid, a heating unit heats the processing fluid to place the processing fluid into a processing receptacle in a supercritical state, and a cooling mechanism forcibly cools an area capable of transferring the heat to the substrate from the heating unit in order to suppress the liquid from being evaporated from the substrate until the substrate is disposed on a seating unit.