Wet Etching Control Using Wafer Thickness Profile Data
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
The challenge in wet etching of semiconductor wafers is the variability in total thickness variation (TTV) due to factors like temperature and humidity, leading to inconsistent quality post-processing, with potential issues such as surface roughness and structural defects.
Innovation Solution
A method involving a dispensing unit that moves continuously along a trajectory while dispensing chemical liquid and rotating the specimen, using thickness profile data to adjust etching settings individually for each specimen, ensuring uniform etching and minimizing discontinuities.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If fixed wet etching settings are used for all specimens, then the process is simple and efficient, but the TTV cannot be controlled within the accepted quality range due to specimen variability
Solution Approach 1:
The patent applies parameter changes by adjusting wet etching process parameters (such as etching time, chemical liquid flow rate, or temperature) based on the measured thickness profile of each specimen. The control unit modifies these parameters dynamically to compensate for TTV, ensuring that each specimen achieves uniform thickness after etching while maintaining overall process efficiency.
Solution Approach 2:
The patent implements feedback control by measuring the thickness profile of each specimen before etching, using this measurement to determine appropriate etching settings, and then applying those settings. This closed-loop feedback mechanism ensures that TTV is controlled within the accepted quality range while adapting to specimen-specific variations.
2Manufacturing precision
If individual specimen control is implemented based on thickness profile, then TTV quality is improved, but the processing time and complexity increase
Solution Approach 1:
The patent applies preliminary action by measuring the thickness profile of each specimen before the wet etching process and pre-determining the optimal etching settings based on this measurement. This allows the actual etching process to proceed efficiently without interruptions, as all control decisions are made in advance based on the thickness profile data.
3Manufacturing precision
If continuous chemical liquid dispensing is used during specimen rotation, then surface coverage is improved, but the risk of discontinuities and defects increases without proper control
Solution Approach 1:
The patent applies parameter changes by dynamically adjusting the chemical liquid dispensing rate and specimen rotation speed based on the thickness profile data. This ensures that areas requiring more etching receive appropriate chemical liquid exposure while preventing over-etching or discontinuities in other areas, thereby maintaining surface coverage without introducing defects.
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 approach maintains consistent TTV within an acceptable range, preventing surface defects and enhancing the reliability of semiconductor wafers by ensuring uniform etching across specimens.
Implementation Method 1
Wet etching is an etching process that takes off material from a specimen or, in other words, substrate material from a substrate by using a chemical liquid or, in other words, a liquid chemical, which may comprise one or more chemical etchants.
Data Source
Figure 1~3
Figure 4~6
Figure 7~9
AI summary
The disclosure relates to a method (200) for controlling a wet etching process (131, 132, 133), the wet etching process (131, 132, 133) using a dispensing unit (19) for dispensing a chemical liquid (18) containing a chemical etchant for etching a specimen surface of a specimen (1), and a rotation unit (31) for rotating the specimen (1), wherein the dispensing unit (19) is continuously moved along a dispensing trajectory (DT) relative to the specimen (1) while the chemical liquid (18) is being dispensed onto the specimen surface and the specimen (1) is being rotated by the rotation unit (31), the method (200) comprising: - obtaining thickness profile data indicative of a thickness profile of a thickness variation of the specimen (1) along a measurement line (ML) on the specimen surface prior to the wet etching process (131, 132, 133); and - obtaining control data for controlling one or more settings of the wet etching process (131, 132, 133) on the specimen surface based on the thickness profile data.