Wedge Roller Stage Mechanism for Precision Height Adjustment
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Solution Overview
Problem
The challenge in semiconductor manufacturing is to accurately adjust the height position of a stage mechanism in inspection apparatuses to improve the focusing accuracy of electron beams, which is crucial for detecting ultrafine patterns on semiconductor wafers, as the critical dimensions of LSI circuits continue to shrink, leading to a need for highly precise inspection techniques.
Innovation Solution
A stage mechanism with a wedge having an inclined surface and a roller that moves horizontally, allowing for coarse and fine adjustments of the table height through a combination of encoder and piezoelectric elements, ensuring precise control and restraint of horizontal movement using elastic bodies.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a large wedge-like member is moved by an encoder servo system to adjust the intermediate table position, then the vertical size of the Z stage becomes large, but the device complexity and space requirement increase
Solution Approach 1:
The Z stage is divided into multiple independent adjustment mechanisms: a coarse adjustment mechanism using wedges and rollers for large displacements, and fine adjustment mechanisms using piezoelectric elements for precise control. This segmentation allows each component to be optimized for its specific function, reducing overall complexity while maintaining high precision.
Solution Approach 2:
The invention converts vertical height adjustment into horizontal wedge movement through inclined surfaces. By moving the wedge horizontally, the roller moves vertically along the inclined surface, achieving table height adjustment without requiring a large vertical travel range, thus compacting the Z stage structure.
2Measurement precision
If piezoelectric elements are used for fine adjustment of the table height, then the adjustment precision is improved, but the device complexity increases
Solution Approach 1:
The invention combines the coarse adjustment mechanism (wedge-roller) with fine adjustment mechanisms (piezoelectric elements) into an integrated Z stage system. The piezoelectric elements are positioned to work in conjunction with the wedge-roller mechanism, merging both adjustment ranges into a unified system that achieves both large and fine displacements without requiring separate independent systems.
Solution Approach 2:
The roller acting on the wedge's inclined surface serves as an intermediary that translates horizontal wedge movement into vertical roller displacement. This intermediary mechanism allows the piezoelectric elements to control vertical position indirectly through the wedge-roller interface, reducing the complexity of direct vertical actuation while maintaining precision.
3Ease of operation
If the wedge is moved horizontally to adjust the roller position vertically, then the table height adjustment is achieved, but horizontal movement restraint is required
Solution Approach 1:
The elastic body acts as a counterbalancing element that applies a restoring force opposite to the horizontal movement direction of the wedge. This elastic restraint mechanism counteracts any unwanted horizontal displacement of the wedge, keeping it constrained to its intended movement path while allowing smooth vertical adjustment of the table through the inclined surface mechanism.
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 solution enables highly accurate adjustment of the table height, enhancing the inspection accuracy by allowing for both coarse and fine movements, thereby improving the detection of pattern defects on semiconductor wafers with reduced size constraints.
Implementation Method 1
a roller that relatively rolls on the inclined surface of the wedge by relative horizontal movement of the wedge
Implementation Method 2
a wedge that is with an inclined surface having a predetermined angle with respect to a horizontal direction
Implementation Method 3
an elastic body that is connected to the table, restrains horizontal movement of the table, and applies an elastic force, in at least one of upward and downward directions, to the table
Implementation Method 4
a fine movement mechanism that supports the roller, goes up and down in accordance with up and down movement of the roller which relatively rolls on the inclined surfaces by the relative horizontal movement of the wedge, and can go up and down more finely than the up and down movement of the roller
Data Source
AI summary
A stage mechanism includes a wedge with an inclined surface having a predetermined angle with respect to a horizontal direction, a roller relatively rolling on the inclined surface of the wedge by relative horizontal movement of the wedge, a fine movement mechanism supporting the roller, going up and down in accordance with up and down movement of the roller which relatively rolls on the inclined surfaces by the relative horizontal movement of the wedge, and capable of going up and down more finely than the up and down movement of the roller, a table supported by the fine movement mechanism, and an elastic body connected to the table, restraining horizontal movement of the table, and applying an elastic force, in at least one of upward and downward directions, to the table.