Heating Method for Stable Thermal Budget in Semiconductor Manufacturing
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Solution Overview
Problem
In semiconductor manufacturing, the thermal budget is difficult to maintain stably due to variations in heating procedures, leading to device failures from uncontrolled diffusion of impurity ions during high-temperature treatments.
Innovation Solution
A method that adjusts the durations of primary and virtual process steps in a heating procedure to maintain a constant total duration, ensuring a stable thermal budget by setting the sum of the first and second durations as a constant, where the first duration is adjusted based on the average and maximum changes in primary procedure durations, and the virtual process step involves annealing in a nitrogen atmosphere.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Length of stationary object
If the primary process duration is extended to form a thicker oxide layer, then the oxide layer thickness is improved, but the thermal budget increases and causes uncontrolled diffusion of impurity ions
Solution Approach 1:
The heating procedure is segmented into multiple distinct steps: a heating step to increase temperature, a primary procedure step for thin film formation, a virtual process step as a dummy heating step, and a cooling step. This segmentation allows independent control of each step's duration and temperature, enabling the total thermal budget to be maintained constant while still achieving the required oxide layer thickness through optimized timing of individual segments.
Solution Approach 2:
The invention changes the parameters of the heating procedure by introducing a virtual process step with specific duration T2 that compensates for variations in the primary procedure duration T1. By adjusting the duration of the virtual process step while keeping the sum (T1+T2) constant, the method maintains stable thermal budget while accommodating variations in primary process requirements for oxide layer formation.
2Reliability
If the primary process duration is reduced to decrease thermal budget, then device stability is improved, but the oxide layer thickness becomes insufficient
Solution Approach 1:
The virtual process step is introduced as a preliminary or compensatory action that ensures the total thermal budget remains constant. By pre-planning and incorporating this dummy heating step with duration T2 = constant - T1, the system ensures that even when the primary procedure duration T1 is reduced, the overall thermal exposure remains sufficient to maintain device stability while the primary process parameters are optimized for adequate oxide layer formation.
3Stability of the object's composition
If the heating procedure is optimized to maintain constant total duration, then thermal budget stability is improved, but the process complexity increases
Solution Approach 1:
The virtual process step acts as an intermediary or buffer element in the heating procedure. This dummy heating step with duration T2 serves as a mediator that absorbs variations in the primary procedure duration T1, thereby maintaining constant total duration (T1+T2). The intermediary step simplifies the control logic by providing a straightforward compensation mechanism rather than requiring complex real-time adjustments to multiple process parameters.
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 approach maintains a stable thermal budget and device performance by keeping the total heating process duration constant, reducing manufacturing costs and preventing device failures from thermal energy excess.
Implementation Method 1
a heating step for increasing the temperature in a reaction furnace from a first temperature to a second temperature
Implementation Method 2
a cooling step for decreasing the temperature in the reaction furnace from the second temperature to the first temperature
Implementation Method 3
as for the thermal oxidation, in case that dry oxygen oxidation is performed at 800° C. on (100) crystallographic plane of Si
Implementation Method 4
The duration of thermal annealing is generally in the order of some minutes or some seconds, so that annealing at 300° C. can essentially remove defects
Data Source
AI summary
The present invention discloses a heating method for maintaining a stable thermal budget. By following the primary procedure with a virtual procedure in such a manner that the total duration of the whole heating process remains constant, it is beneficial to maintain a stable thermal budget and further to maintain a stable device performance.