LED Illuminance Uniformity Control for Semiconductor Exposure
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Solution Overview
Problem
Existing semiconductor manufacturing technologies face challenges in achieving high accuracy and uniformity of illuminance distribution in strip-shaped irradiation regions, particularly due to variations in LED characteristics, which affect the in-plane uniformity of circuit patterns and require costly and large-scale apparatuses for EUV exposure.
Innovation Solution
An optical processing apparatus with a linear arrangement of light-emitting blocks, a storage unit for illuminance distribution patterns, and an arithmetic processing unit to determine current command values for each block, allowing for precise adjustment of the illuminance distribution pattern to match a target pattern, thereby reducing variations among apparatuses.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If LED characteristics are used for illuminance distribution, then the apparatus can be downsized and cost reduced, but the in-plane uniformity of line width deteriorates due to variations among individual LEDs
Solution Approach 1:
The illuminance distribution adjustment is segmented by dividing the irradiation region into multiple measurement positions along the lengthwise direction. Each position's illuminance is independently measured and used to determine adjustment amounts for specific light-emitting blocks, enabling localized precision control without requiring a large-scale apparatus.
Solution Approach 2:
The invention changes the electrical parameter (drive current) of individual light-emitting blocks to adjust their light emission intensity. By storing and applying adjustment amounts to the drive currents of specific light-emitting blocks based on measured illuminance distribution, the system achieves uniform line width while using compact LED-based illumination.
2Ease of operation
If simple drive current adjustment is performed, then the operation is simplified, but the illuminance uniformity cannot be achieved due to individual differences and time variations in LED characteristics
Solution Approach 1:
The system performs preliminary measurement of the actual illuminance distribution pattern at multiple positions before final exposure. Based on these measurements, adjustment amounts are calculated and stored in advance for each light-emitting block, enabling automatic compensation for LED variations without complex manual adjustment during operation.
Solution Approach 2:
The invention implements a feedback mechanism where the illuminance distribution is measured at multiple positions, the measured values are compared against target values, and adjustment amounts are determined based on the deviations. This closed-loop feedback ensures uniform illuminance despite individual LED variations and time-dependent characteristic changes.
3Productivity
If batch exposure is performed with strip-shaped irradiation region, then throughput is improved, but the in-plane uniformity of line width deteriorates due to illuminance non-uniformity in the lengthwise direction
Solution Approach 1:
The system dynamically adjusts the drive currents of individual light-emitting blocks based on pre-stored adjustment amounts. This dynamic parameter adjustment compensates for illuminance non-uniformity across the strip-shaped irradiation region, enabling batch exposure with uniform line width without sacrificing throughput.
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 easy and accurate adjustment of the illuminance distribution pattern in the lengthwise direction, ensuring high uniformity and reducing differences among optical processing apparatuses, thus meeting the requirements for miniaturized semiconductor circuit patterns without the need for large-scale equipment.
Implementation Method 1
an optical irradiation unit in which a plurality of light-emitting blocks, each formed of one light-emitting diode or a plurality of light-emitting diodes connected in series, are linearly arranged
Data Source
AI summary
An illuminance distribution response amount as the change amount of the illuminance distribution pattern, associating the position in the irradiation region in the lengthwise direction with the change amount of the illuminance with respect to the change in the drive current, has previously been acquired and stored in a storage unit for each light-emitting block. There is provided an arithmetic processing unit that determines (estimates) a current command value of each of the light-emitting blocks based on a present current command value of each of the light-emitting blocks and the change amount of the illuminance distribution pattern of each light-emitting block in order to bring a present illuminance distribution pattern in the irradiation region in a lengthwise direction close to a target illuminance distribution pattern.