Substrate Transfer Controller for Post-Exposure Bake Delay Reduction
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Solution Overview
Problem
In semiconductor photolithography processes, delays often occur during the loading of substrates into post-exposure bake units due to inefficient time management and transfer sequencing, leading to increased cycle times and potential delays in the wafer treatment process.
Innovation Solution
A substrate transfer control method and apparatus that includes a controller to select the post-exposure bake unit with the least delay time, perform evasion processes by placing substrates in buffer modules when progress is impossible, and manage the loading of substrates to minimize delays by prioritizing transfer to available units and avoiding overloading.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of time
If substrates are transferred sequentially through fixed process units, then the process follows a simple control logic, but delay time increases when the next process unit is occupied
Solution Approach 1:
The transfer control system dynamically selects the next process unit based on real-time availability status. Instead of following a fixed sequential order, the controller evaluates multiple possible destination units and chooses the one that can accept the substrate immediately, thereby minimizing delay time while adapting to changing system conditions
Solution Approach 2:
Buffer modules are introduced as intermediary storage units between the exposure module and post-exposure bake units. When all PEB units are occupied, substrates can be temporarily placed in buffer modules, preventing idle time in the transfer process and enabling continuous operation of the exposure module
2Productivity
If multiple post-exposure bake units are provided, then substrate processing capacity increases, but selecting the optimal unit becomes more complex
Solution Approach 1:
The controller continuously monitors the availability status of each post-exposure bake unit and uses this feedback information to make real-time selection decisions. The system tracks which units are occupied and which are available, automatically selecting the most suitable destination unit based on current system state without requiring complex manual intervention
3Loss of time
If substrates wait in queue for available post-exposure bake units, then process sequencing is simplified, but average delay time increases
Solution Approach 1:
The controller proactively identifies and selects the next available post-exposure bake unit before the substrate is fully processed in the exposure module. By anticipating future availability and preparing the transfer path in advance, the system minimizes waiting time and ensures continuous flow without requiring complex real-time queue management
Data Source
AI summary
Disclosed is a substrate treating apparatus including a coating module, an exposure module, a plurality of developing modules, and a transfer unit that performs transfer of a substrate between the modules. The plurality of developing modules include a plurality of post-exposure bake units that perform a bake process on a substrate on which an exposure process is completely performed in the exposure module. The substrate treating apparatus further includes a controller that controls the transfer of the substrate by the transfer unit. When transferring a substrate from the exposure module to the plurality of post-exposure bake units, the controller performs control to select a post-exposure bake unit in which the least delay time occurs, among the plurality of post-exposure bake units and to transfer the substrate to the selected post-exposure bake unit.