Semiconductor Dispatch Method Using Overlay Error Reference Curves
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Solution Overview
Problem
Conventional real-time dispatch systems in semiconductor manufacturing focus on time gaps and lot importance, ignoring production conditions of previous and next product lots, leading to reduced yield due to uneven exposure energy between adjacent lots.
Innovation Solution
A dispatch method that acquires an overlay error reference curve, sets an overlay error range, determines if the error falls within this range, and pre-cools equipment if necessary to maintain acceptable exposure energy differences between product lots, ensuring consistent yield.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional RTD system dispatch method is used, then dispatch speed is maintained, but overlay error control is poor leading to reduced yield
Solution Approach 1:
The system performs preliminary actions by acquiring overlay error reference curves and setting overlay error ranges before actual exposure. The RTD system pre-calculates optimal dispatch sequences considering equipment temperature effects on overlay error, and pre-positions product lots to be machined based on predicted thermal conditions, thereby preventing yield reduction before it occurs.
Solution Approach 2:
The system implements feedback mechanisms by continuously monitoring actual overlay errors and comparing them against reference curves. The RTD system uses this feedback to dynamically adjust dispatch decisions, modifying the exposure sequence of product lots based on real-time equipment temperature conditions and observed overlay error trends, thereby maintaining yield while adapting to changing conditions.
2Manufacturing precision
If equipment pre-cooling is performed, then overlay error is controlled within acceptable range, but production time increases
Solution Approach 1:
The system applies dynamics by making the cooling strategy adaptive rather than static. The RTD system dynamically determines cooling requirements based on the specific overlay error conditions, equipment temperature trends, and the thermal characteristics captured in reference curves. Cooling actions are triggered only when and where needed, with variable duration and intensity, thereby maintaining overlay error control while minimizing production time loss.
Solution Approach 2:
The system changes parameters by using overlay error reference curves that characterize equipment thermal behavior under different operating conditions. By analyzing these curves, the RTD system identifies optimal cooling timing and duration parameters that achieve acceptable overlay error control with minimal time penalty, rather than using fixed or excessive cooling periods.
3Manufacturing precision
If overlay error monitoring is implemented, then exposure energy difference is controlled, but measurement complexity increases
Solution Approach 1:
The system uses copying by creating overlay error reference curves that represent typical equipment thermal behavior patterns. Instead of performing complex real-time analysis of every measurement, the RTD system compares actual overlay errors against these pre-established reference curves, using the curves as templates to quickly assess whether cooling action is needed and to predict the impact of cooling decisions on exposure energy consistency.
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 method ensures that the difference in exposure energy between adjacent product lots is within an acceptable range, preventing reduced yield and allowing continuous exposure without affecting semiconductor product quality.
Implementation Method 1
the equipment needs to be pre-cooled, thereby allowing the overlay error to be within an acceptable range
Data Source
AI summary
The present application relates to a dispatch method for a production line in a semiconductor process, a storage medium and a semiconductor device. The dispatch method for a production line in a semiconductor process can acquire an overlay error reference curve of a product lot to be exposed in equipment and set an overlay error range according to the overlay error reference curve. At the end of exposure, an overlay error for the product lot to be exposed can be acquired, and it can be determined whether the overlay error falls into the overlay error range. If the overlay error for the product lot to be exposed does not fall into the overlay error range, the product lot to be exposed can be continuously machined by this equipment.