Heating Plate Suction Timing for Wafer Warpage Correction
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Solution Overview
Problem
Wafers with warpage during heat processing in semiconductor manufacturing experience non-uniform heat conduction, affecting the line width uniformity of resist patterns due to varying distances between the wafer and the heating plate.
Innovation Solution
A heat processing method where suction start timings for multiple suction ports on the heat processing plate are adjusted based on the substrate's deformed state, with earlier suction timing for portions deformed upward to correct warpage quickly and ensure uniform heating.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If a wafer with warpage is mounted on a heating plate, then the wafer can be heat-processed, but the distance between the wafer and heating plate varies causing non-uniform heat conduction
Solution Approach 1:
The patent applies preliminary action by detecting wafer warpage before heat processing and pre-adjusting the suction start timings for each suction port based on the detected deformation. This pre-positioning of suction activation ensures that warpage is corrected before the wafer is exposed to heat, eliminating distance variations that would cause non-uniform heat conduction and subsequent line width defects.
Solution Approach 2:
The patent implements local quality by assigning different suction start timings to different suction ports based on the local warpage characteristics of the wafer. Each suction port operates according to the specific deformation state of its corresponding region, enabling localized correction of warpage to achieve uniform heat conduction across the entire wafer surface.
2Manufacturing precision
If suction is applied uniformly across all suction ports simultaneously, then the mounting process is simple, but warpage correction is insufficient leading to heat processing defects
Solution Approach 1:
The patent applies dynamics by transitioning from static simultaneous suction activation to dynamic sequential suction activation. The control unit adjusts the timing of suction port activation based on real-time warpage detection, creating a dynamic suction pattern that adapts to the wafer's deformation state. This dynamic approach enables precise warpage correction while maintaining manageable system complexity through programmable control.
3Manufacturing precision
If suction start timings are adjusted based on warpage detection, then uniform heat processing is achieved, but the process time increases due to sequential suction activation
Solution Approach 1:
The patent applies the skipping principle by rapidly transitioning through the sequential suction activation process. The control unit activates suction ports in a optimized sequence with minimal delays between activations, rushing through the warpage correction phase as quickly as possible while still achieving the necessary correction. This minimizes the time penalty imposed by sequential activation while maintaining heat processing uniformity.
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 method allows for uniform heat processing of substrates with warpage, enhancing the uniformity of resist patterns and increasing yield by correcting warpage variations during heat processing.
Implementation Method 1
sucking the substrate via the suction ports based on the set suction start timings to attract the substrate onto the heat processing plate
Implementation Method 2
the distance between the wafer and the heating plate varies within the wafer to fail to uniformly conduct heat from the heating plate to the wafer
Data Source
AI summary
In the present invention, a plurality of suction ports are provided in a heating plate of a heat processing apparatus. The suction ports are provided at a central portion, an intermediate portion, and a peripheral portion of a substrate mounting surface of the heating plate, respectively. The warped state of the substrate before heat-processed is measured, so that when the substrate warps protruding downward, the suction start timing via a suction port corresponding to the outer peripheral portion of the substrate is set to be relatively early as compared to the suction start timings via the other suction ports, and when the substrate warps protruding upward, the suction start timing via the suction port corresponding to the central portion of the substrate is set to be relatively early as compared to the suction start timings via the other suction ports. This allows a portion of the substrate bending upward to be sucked first when the substrate is mounted on the heating plate, thereby quickly performing correction of the warpage of the substrate to uniformly heat the substrate.