Wafer Cooling Plate Structure for Warp-Suppressed Heat Treatment
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Solution Overview
Problem
Conventional heat treatment devices face challenges in suppressing warping of semiconductor wafers during cooling, leading to non-uniform cooling and reduced exposure resolution due to complex structures and the need for high negative pressure, which complicates efficient processing and throughput.
Innovation Solution
A heat treatment device with a cooling plate featuring projections and suction holes, along with a flexible coolant-containing bag or zigzag coolant passage, applies uniform suction to maintain a consistent space between the wafer and the cooling plate, ensuring reliable suppression of warping and efficient cooling, while also serving as a transporting mechanism to improve processing efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If a multi-layer film is formed and multiple applying operations are repeated to miniaturize photoresist patterns, then exposure resolution is improved, but wafer warping occurs due to stacking of films and temperature changes
Solution Approach 1:
The cooling plate is pre-heated to a temperature close to the wafer's processing temperature before the wafer is placed on it. This preliminary temperature matching prevents sudden thermal contraction that would cause warping during the cooling process, while still allowing high-resolution pattern formation through multiple film layers
2Stability of the object's composition
If a warp measuring unit and selective blow/suction holes are used to suppress wafer warping, then wafer flatness is improved, but device complexity increases and cooling time is extended
Solution Approach 1:
The cooling plate itself serves the dual function of both cooling the wafer and suppressing warping through its temperature control capability. By pre-heating the plate to match wafer temperature, the system eliminates the need for separate warp measurement and active blow/suction control mechanisms, simplifying the overall device structure
3Stability of the object's composition
If negative pressure is applied between the wafer and stage to keep uniform space, then wafer flatness is improved, but large negative pressure is required and complicated warp forms cannot be suppressed reliably
Solution Approach 1:
Instead of applying large negative pressure to suppress warping, the invention changes the temperature parameter of the cooling plate to match the wafer's temperature. This temperature parameter change prevents thermal contraction-induced warping without requiring excessive negative pressure, and works effectively for various warp forms
4Productivity
If the cooling plate is used for both cooling and transporting the wafer, then productivity is improved, but the cooling plate structure becomes more complex
Solution Approach 1:
The cooling plate is designed with projections that serve multiple functions: they maintain uniform space between the wafer and plate for effective cooling, and simultaneously act as transport features when the plate moves to transfer the wafer between processing stations. This multi-functionality improves productivity without requiring separate cooling and transport mechanisms
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 device effectively suppresses wafer warping, enables uniform cooling, and enhances processing efficiency by maintaining a consistent space and applying uniform suction, thereby improving heat treatment outcomes and throughput.
Implementation Method 1
a plurality of suction holes arranged near the respective projections and communicated with a suction device
Implementation Method 2
The cooling plate includes a coolant passage
Data Source
AI summary
In a heat treatment device including a heating chamber having a heating plate heating a semiconductor wafer, a cooling plate cooling the wafer heated by the heating chamber, and a transporting device transporting the wafer into and from the heating chamber, the cooling plate is provided with a coolant passage, a plurality of projections carrying the wafer with a space between the wafer and the surface of the cooling plate, and suction holes neighboring to the respective projections and connected to a suction device.