Wafer Backside Flattening Using Piezoelectric Defect Detection
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Solution Overview
Problem
Existing semiconductor manufacturing processes result in foreign objects, film residue, and uneven films on the backside of wafers, leading to defocusing issues during exposure processes, affecting imaging quality and pattern profiles.
Innovation Solution
A system and method utilizing a vacuum stage with piezoelectric elements to detect deformations on the wafer backside, transmitting data to a flattening apparatus for customized polishing based on the detected deformations, ensuring precise removal of foreign objects and uneven films to achieve a flattened surface.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional manufacturing processes are used, then productivity is maintained, but foreign objects and film residue remain on the backside of wafers causing defocusing issues
Solution Approach 1:
The patent applies preliminary action by performing flattening and foreign object removal on the backside of the wafer before the exposure process. The system detects deformations and removes foreign objects in advance, preventing defocusing issues during exposure rather than correcting them afterward.
Solution Approach 2:
The patent implements feedback by using piezoelectric elements to detect deformations on the wafer backside, transmitting this data to a controller that directs the flattening apparatus to针对性地 flatten specific areas. This closed-loop feedback system ensures precise removal of foreign objects and uneven films based on actual detected conditions.
2Object-affected harmful factors
If blanket polishing is applied to remove foreign objects, then foreign objects are removed, but over-polishing damages the wafer surface
Solution Approach 1:
The patent applies local quality by transitioning from blanket polishing to localized flattening. The system detects specific areas with foreign objects or deformations and applies flattening only to those localized regions, rather than polishing the entire wafer surface. This prevents over-polishing and damage to areas that do not require treatment.
Solution Approach 2:
The system performs preliminary detection of foreign objects and deformations using piezoelectric elements before applying any flattening. This preliminary action enables precise targeting of only the necessary areas, avoiding unnecessary polishing and potential damage to the wafer surface.
3Productivity
If no flattening process is applied, then manufacturing steps are reduced, but defocusing occurs during exposure affecting pattern profiles
Solution Approach 1:
The patent implements local quality by applying flattening only to specific areas of the wafer backside that exhibit deformations or foreign objects, rather than performing blanket flattening on the entire surface. This localized approach maintains manufacturing efficiency while ensuring sufficient flatness in critical areas for exposure quality.
Solution Approach 2:
The system performs preliminary detection and selective flattening before exposure, ensuring that only necessary areas are treated. This preliminary action prevents defocusing issues without requiring extensive manufacturing steps, thereby maintaining productivity while improving pattern profile quality.
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 solution effectively prevents over-polishing and improves the quality of exposure processes by reducing defocusing, enhancing imaging dimensions and pattern profiles of the wafer.
Implementation Method 1
The stage includes piezoelectric elements configured to detect deformations on the backside of the wafer
Implementation Method 2
placing the wafer on a vacuum stage
Data Source
AI summary
A system and a method for manufacturing a semiconductor device are provided. The system includes a processor, a stage for supporting a first wafer, and a polishing device. The stage is configured to sense characteristic data of a first surface of the first wafer, wherein the stage is electrically coupled to the processor and configured to transmit the sensed characteristic data of the first surface of the first wafer to the processor. The polishing device is electrically coupled to the processor and configured to remove foreign objects from the first surface of the first wafer based on the sensed characteristic data.