Wynne-Dyson Optical System Variable Magnification
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Solution Overview
Problem
Current photolithography tools face challenges in achieving high throughput and yield due to limitations in die size and registration errors, particularly in handling multiple-die formats and compensating for overlay errors in large format semiconductor wafer manufacturing.
Innovation Solution
A Wynne-Dyson optical system with variable magnification, incorporating first and second total-internal-reflection prisms and a positive lens group with axially movable split lens elements, allowing for adjustments up to 500 parts per million to accommodate multiple-die formats and compensate for registration errors.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a fixed 1× magnification optical system is used, then the system structure is simple and stable, but registration errors cannot be compensated and multiple-die format flexibility is limited
Solution Approach 1:
The patent applies the dynamics principle by making the lens group movable along the optical axis. This allows the optical system to dynamically adjust its magnification from a fixed 1× to variable magnification (e.g., 0.99× to 1.01×), enabling compensation for registration errors while maintaining relative structural simplicity. The movable lens group transforms a static optical system into a dynamic one that can adapt to different registration requirements.
Solution Approach 2:
The patent implements parameter changes by varying the magnification parameter of the optical system. By changing the magnification from a fixed 1× to a variable range (e.g., 0.99× to 1.01×), the system can compensate for registration errors in lithographic pattern overlay. This parameter adjustment is achieved through the movable lens group that alters the effective focal length or image distance, thereby changing the magnification parameter to correct overlay misalignments.
2Productivity
If the field size is increased to handle four to six dies, then throughput increases, but the system must maintain precise registration across the larger field
Solution Approach 1:
The movable lens group provides dynamic magnification adjustment capability that can be used to compensate for registration errors that may occur across larger field sizes. This dynamic adjustment allows the system to maintain manufacturing precision even when handling four to six dies simultaneously, thereby enabling increased throughput without sacrificing registration accuracy.
3Area of stationary object
If the optical system is designed for large field size, then multiple-die formats can be handled, but the complexity of maintaining 1× magnification precision increases
Solution Approach 1:
By introducing a movable lens group, the system gains dynamic magnification adjustment capability. This allows the optical system to maintain 1× magnification precision across large field sizes by compensating for any deviations through axial movement of the lens group. The dynamic adjustment simplifies magnification control compared to designing a completely new optical system for each magnification requirement.
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 system enables efficient handling of four to six dies per wafer with reduced stepping time, partially compensating for registration errors, thereby enhancing throughput and yield in semiconductor manufacturing.
Implementation Method 1
first and second total-internal-reflection (TIR) prisms
Data Source
AI summary
A 1× Wynne-Dyson optical system for microlithography having a variable magnification is disclosed. The 1× Wynne-Dyson optical system has first and second prisms, and a positive lens group that includes a split lens having first and second split lens elements that reside adjacent the first and second prisms, respectively. The first and second split lens elements are axially movable to change the magnification by up to about 500 parts per million. An adjustable positive lens group for a 1× Wynne-Dyson optical system is also disclosed, wherein the positive lens group allows for small changes in the optical system magnification.