Wafer Carrier Suction Control for Flatness and Position
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Solution Overview
Problem
The challenge in the lithography process for manufacturing electronic devices, such as semiconductor and liquid crystal display devices, is the risk of warping and positional deviation of larger wafers like 450 mm, which affects exposure accuracy due to differences in driving velocity between suction and support members during non-contact suction and support methods.
Innovation Solution
A carrier system that includes a suction member generating a gas flow to create a suction force, a measurement device for shape information, and a driver for vertical movement, controlled by a controller to maintain the object's flatness and correct positional deviations, ensuring precise mounting on an object mounting section.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Shape
If non-contact suction method is used for larger wafers (450mm), then flatness is maintained, but positional deviation (rotation deviation) occurs at unacceptable levels
Solution Approach 1:
A marker is introduced as an intermediary element on the wafer surface that can be detected by the carrier member. This marker serves as a reference point that enables the carrier member to identify and correct rotational position deviations, thereby maintaining both flatness and positional accuracy during non-contact suction and transport operations.
2Stability of the object's composition
If support from below is added during loading, then warping is reduced, but driving velocity difference between suction member and support member causes unacceptable warping
Solution Approach 1:
A feedback mechanism is implemented where the carrier member detects the wafer's rotational position using a marker and adjusts its suction force distribution accordingly. This feedback control enables coordinated movement between the suction member and support member, eliminating warping caused by velocity differences while maintaining wafer stability during loading operations.
3Productivity
If 450mm wafer size is used, then number of dies per wafer increases, but warping risk increases due to reduced intensity and rigidity
Solution Approach 1:
The system applies counteracting forces through the carrier member's suction mechanism and support member's upward force, balanced by feedback control based on marker detection. This counterbalance compensates for the reduced rigidity of larger wafers, preventing warping while enabling the use of 450mm wafers to increase die output.
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 system effectively maintains high flatness and corrects positional deviations, enabling accurate exposure and pattern formation on larger wafers, enhancing the manufacturing process by reducing the risk of warping and improving exposure accuracy.
Implementation Method 1
a suction member which has an opposing section opposed to the object, the suction member forming a gas flow between the opposing section and the object to generate a suction force with respect to the object
Data Source
AI summary
A carrier system and method carries an object to an object mounting member provided with an object mounting section. The system includes: a measurement device which obtains information related to a flatness of the object; a carrier member that carries the object; and a controller which controls a driving speed of the carrier member using the information related to the flatness of the object obtained by the measurement device.