Exposure Apparatus Substrate Height Alignment
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Solution Overview
Problem
In semiconductor device packaging, especially with FOWLP, achieving accurate height alignment of substrates with steps or varying heights is challenging due to difficulties in flattening molding materials and removing layers, leading to inaccuracies in measurement and exposure processing.
Innovation Solution
An exposure apparatus that measures substrate height at multiple points and controls height and tilt, rearranging the shot region to increase the number of measurement points in flat regions, allowing for more accurate alignment by shifting the shot region to positions where more measurement points can be used, thereby improving height direction alignment.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of stationary object
If measurement points are arranged in two regions with different heights due to steps, then the coverage area increases, but the alignment accuracy in the height direction deteriorates
Solution Approach 1:
The patent applies local quality by selectively weighting measurement points based on their local height characteristics. Measurement points in flat regions are given higher weights, while points in stepped regions are given lower weights or excluded, allowing the system to adapt to local surface variations and maintain high alignment accuracy in the height direction
Solution Approach 2:
The patent changes the parameter of measurement point selection by dynamically determining which measurement points to use based on height variation analysis. The system identifies flat regions versus stepped regions and adjusts the set of usable measurement points accordingly, optimizing both coverage and accuracy
2Manufacturing precision
If only measurement points in flat regions are used for alignment, then the alignment accuracy improves, but the number of usable measurement points decreases
Solution Approach 1:
The patent changes the parameter of measurement point utilization by introducing a weighting mechanism. Instead of simply selecting or rejecting measurement points based on flatness, the system assigns different weights to measurement points based on their reliability, thereby increasing the effective number of usable measurement points while maintaining accuracy
3Loss of information
If all measurement results from multiple measurement points are used, then the data coverage increases, but the alignment accuracy deteriorates due to inclusion of points in stepped regions
Solution Approach 1:
The patent applies local quality by differentiating between measurement points in flat regions and stepped regions. The system analyzes height variations locally and assigns different levels of confidence or weight to measurement results based on their local environment, thereby preserving valuable data from stepped regions while prioritizing data from flat regions
Solution Approach 2:
The patent introduces an intermediary mechanism (weighting factor) between the raw measurement data and the final alignment calculation. This intermediary allows the system to incorporate all measurement data while modulating their influence based on reliability, effectively bridging the gap between comprehensive data coverage and high alignment accuracy
Data Source
AI summary
The present invention provides an exposure apparatus which exposes a substrate, comprising a measurement unit configured to measure a height of the substrate at each of a plurality of measurement points, and a control unit configured to control the height of the substrate based on measurement results obtained by the measurement unit, and control an operation to arrange a shot region of the substrate in a first position and expose the shot region, wherein the shot region includes a plurality of partial regions, and the control unit causes the measurement unit to measure the height of the substrate by arranging the shot region in a second position different from the first position so that the number of measurement points arranged in the plurality of partial regions is larger than that when arranging the shot region in the first position.