Exposure Apparatus Wafer Warp Dynamic Conveyance Control
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Solution Overview
Problem
Semiconductor manufacturing processes face issues with wafer warpage causing conveyance errors and distortions, which affect alignment and exposure precision, leading to potential wafer drop and reduced throughput.
Innovation Solution
The solution involves dynamically adjusting substrate moving speed, attraction pressure, and scan parameters based on measured wafer warp, and selecting optimal alignment marks for advanced global alignment (AGA) measurements, thereby correcting local distortions and improving precision without relying on focus sensor measurements.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If constant moving speed and attraction pressure are used regardless of wafer shape, then the device operation is simple, but wafer dropping and conveyance errors occur due to wafer warp
Solution Approach 1:
The patent implements dynamic adjustment of moving speed and attraction pressure based on real-time wafer warp measurements. The system transitions from fixed constant parameters to dynamically variable parameters that adapt to the actual wafer state, preventing wafer dropping and conveyance errors while maintaining operational simplicity through automated control
Solution Approach 2:
The system changes physical parameters (moving speed, attraction pressure) based on measured wafer conditions. By monitoring wafer warp and adjusting parameters accordingly, the system resolves the contradiction between maintaining simple operation and ensuring reliable wafer conveyance under varying warp conditions
2Manufacturing precision
If focus sensor measurement is used to measure wafer surface shape, then wafer surface registration is achieved, but throughput is reduced due to additional measurement time
Solution Approach 1:
The patent performs wafer surface shape measurement before the exposure process using the same measurement system. By preparing the wafer surface registration data in advance, the system eliminates the need for additional focus sensor measurements during exposure, thereby maintaining high throughput while ensuring precise wafer surface registration
Solution Approach 2:
The measurement system serves multiple functions: it measures wafer surface shape for registration purposes and also provides data for determining optimal alignment marks and adjusting exposure parameters. This multi-functionality eliminates the need for separate focus sensor measurements, improving throughput while maintaining manufacturing precision
3Measurement precision
If alignment marks are selected without considering wafer warp, then the alignment process is simple, but AGA measurement precision is reduced due to local distortion
Solution Approach 1:
The patent applies the principle of local quality by selecting alignment marks based on local wafer conditions (warp and distortion characteristics) rather than using a uniform approach. The system identifies regions with minimal distortion caused by wafer warp and selects alignment marks from those regions, thereby maintaining high AGA measurement precision while managing complexity through localized optimization
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 effectively reduces wafer conveyance errors, enhances AGA measurement precision, and increases throughput by adapting to wafer warpage, ensuring accurate and efficient semiconductor device manufacturing.
Implementation Method 1
a wafer conveying hand, a prealignment stage and a wafer stage are arranged, respectively, to convey a wafer while holding the same by means of a vacuum pressure
Data Source
AI summary
A device manufacturing apparatus includes a conveying device which conveys a substrate, an acquiring device to acquire an amount of warpage of the substrate, based on a measurement or an input, a storing device which stores a database representing a correspondence between a parameter related to a conveying condition and the warpage amount of the substrate, and a controller which controls, based on the database, the conveying device to convey the substrate in accordance with a parameter corresponding to the warpage amount acquired by the acquiring device.