Exposure Apparatus Illuminance Uniformity Control
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Solution Overview
Problem
Existing semiconductor manufacturing processes face challenges in achieving uniform exposure across the whole surface of a substrate due to LED deterioration, leading to non-uniform Critical Dimension (CD) of resist patterns, as the exposure amounts vary across different portions of the wafer.
Innovation Solution
An exposure apparatus with independently controllable light irradiation units and a light receiving unit to detect illuminance distribution, allowing for adjustment of light quantities to ensure uniform exposure across the substrate, preventing deviations in exposure amounts.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If LEDs are used for exposing the whole surface of the substrate, then the exposure process can be simplified and productivity improved, but the LEDs deteriorate with use time causing non-uniform exposure amounts across the substrate
Solution Approach 1:
The illumination system is divided into multiple independently controllable light irradiation units (e.g., multiple LED arrays or modules). Each unit can have its light quantity adjusted separately, allowing compensation for deterioration in specific regions while maintaining overall uniform exposure across the substrate surface.
Solution Approach 2:
Different regions of the substrate receive locally optimized illumination by adjusting the light quantity of individual light irradiation units based on their respective deterioration states. This enables non-uniform control of light emission to achieve uniform exposure results across the entire substrate area.
2Ease of operation
If constant current is supplied to LEDs, then the system operation is simple, but the exposure amounts become non-uniform due to LED deterioration
Solution Approach 1:
A feedback mechanism is implemented where the actual exposure amounts are measured (through illuminance sensors or test patterns), and based on these measurements, the light quantities of individual light irradiation units are adjusted to compensate for LED deterioration, maintaining uniform exposure across the substrate.
Solution Approach 2:
The operating parameters (light quantity/current) of individual light irradiation units are dynamically changed based on their deterioration state. By adjusting these parameters, the system compensates for LED aging effects and maintains uniform exposure amounts across all regions of the substrate.
3Device complexity
If the whole surface of the substrate is exposed using a fixed LED array configuration, then the device structure is simple, but uniform exposure cannot be maintained as LEDs deteriorate over time
Solution Approach 1:
The LED array is segmented into multiple independently controllable light irradiation units, each capable of individual adjustment. This segmentation adds minimal structural complexity while enabling precise control to compensate for deterioration and maintain uniform exposure across the substrate.
Solution Approach 2:
The exposure system transitions from a static, fixed LED array to a dynamic configuration where the light quantity of each unit can be adjusted in response to deterioration. This dynamic adaptability allows the system to maintain uniform exposure performance throughout the LED operational life with minimal structural additions.
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 ensures uniform exposure across the substrate, preventing deviations in the Critical Dimension of resist patterns and maintaining consistent processing results by adjusting light quantities based on detected illuminance distribution.
Implementation Method 1
a plurality of light irradiation units configured to emit light independently of each other to different positions in a right and left direction on a surface of the substrate
Implementation Method 2
a light receiving unit configured move within the irradiation area between one end and the other end of the irradiation area in the right and left direction in order to detect an illuminance distribution of the irradiation area
Data Source
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AI summary
An exposure apparatus includes a stage (33) on which a substrate (W) is placed, a plurality of light irradiation units (46) configured to emit light independently of each other to different positions in a right and left direction on a surface of the substrate, so as to form a strip-like irradiation area (30) extending from one end of the surface of the substrate to the other end of the substrate, a stage moving mechanism (36) configured to move the stage in a back and forth direction relative to the irradiation area, such that the whole surface of the substrate is exposed, and a light receiving unit (51, etc.) configured move in the irradiation area between one end and the other end of the irradiation area in order to detect an illuminance distribution of the irradiation area in a longitudinal direction of the Irradiation area.