Semiconductor Exposure Dose Adjustment via Resist Dimension Feedback
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing semiconductor manufacturing techniques face challenges in accurately managing dimensional variations and focus position shifts during the exposure process, leading to instability in resist pattern dimensions and shape, which affects the performance and yield of semiconductor devices.
Innovation Solution
A manufacturing method and system that measures past resist pattern dimensions and focus positions to calculate and adjust exposure dose and focus offset values in real-time, using a database-driven approach to match target values, thereby reducing dimensional and shape variations without requiring pre-inspection work.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If exposure dose and focus conditions are adjusted to reduce resist dimension variation, then manufacturing precision improves, but measurement and control complexity increases
Solution Approach 1:
The patent implements a feedback mechanism where resist dimensions are measured after exposure, and the measured values are fed back to adjust exposure conditions for subsequent wafers. The focus position shift amount calculated from resist dimension measurements is used to correct exposure conditions, creating a closed-loop control system that continuously improves manufacturing precision without requiring overly complex real-time measurement systems.
Solution Approach 2:
The patent performs preliminary measurements of resist dimensions on test wafers before production exposure. By pre-calculating the focus position shift amount and exposure dose correction values based on these preliminary measurements, the system prepares correction parameters in advance that are then applied to subsequent production wafers, avoiding the need for complex real-time adjustment mechanisms during high-speed production.
2Measurement precision
If multiple resist patterns are formed for focus measurement, then measurement accuracy improves, but productivity decreases
Solution Approach 1:
The patent extracts the focus measurement function from the main production exposure process by using separate test wafers with specific resist patterns dedicated to focus measurement. This allows focus position to be determined without interfering with the high-speed production exposure of actual product wafers, thereby maintaining productivity while achieving accurate focus measurement through specially designed test patterns.
Solution Approach 2:
The patent uses test wafers as copies or proxies for measuring focus position and resist dimension characteristics. Instead of measuring every production wafer in detail, representative test wafers are exposed and measured to derive focus shift amounts that are then applied to correct all production wafers, reducing measurement workload while maintaining measurement precision through representative sampling.
3Manufacturing precision
If pre-inspection work is performed to measure resist dimensions, then manufacturing precision improves, but loss of time increases
Solution Approach 1:
The patent makes the measurement system multi-functional by using the same resist dimension measurement process to serve both quality control (determining focus shift amount) and process control (correcting exposure conditions) functions. By integrating these functions, the system achieves high manufacturing precision without requiring separate dedicated inspection time, as the measurement serves dual purposes and enables real-time correction.
Solution Approach 2:
The patent maintains continuous useful action by immediately using the measured resist dimension data to calculate and apply exposure condition corrections without interrupting the production flow. The measurement and correction processes are tightly coupled and performed in sequence without significant delays, ensuring that the useful action of improving resist dimension accuracy continues uninterrupted through real-time feedback and adjustment.
Data Source
AI summary
In an exposure process forming a predetermined circuit pattern of a semiconductor device on a wafer, a resist dimension of the resist pattern formed on a wafer and a focus position in the exposure process at a past time are measured. A resist dimension and a focus position of a wafer to which the exposure process is secondly performed are estimated by using measurement results of the measured resist dimension and focus position, and a focus offset value is calculated by using estimated values of the estimated resist dimension and focus position. Then, an exposure dose is calculated with considering this focus offset value, and a resist pattern is formed on the wafer to which the exposure process is performed by using the calculated exposure dose and focus offset value.