Microwave Heating for Semiconductor Substrate Warpage
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Solution Overview
Problem
During the heat treatment process for semiconductor substrates, non-uniform in-plane temperature can cause warpage or cracking due to the use of electromagnetic waves in existing technologies.
Innovation Solution
A substrate processing apparatus that includes a process chamber with a microwave oscillator and a controller to perform a heating process using microwaves with a stepwise power pattern, alternating between supply and stop times, and a modifying process at a higher microwave power to maintain uniform temperature and prevent substrate deformation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If electromagnetic waves are used for heat treatment to process high-density substrates, then processing capability for high-density substrates is improved, but substrate warpage or cracking occurs due to non-uniform in-plane temperature
Solution Approach 1:
The patent applies periodic action by alternately performing microwave irradiation and pause periods during the heat treatment process. The microwave irradiation is conducted in multiple cycles with interruption periods, allowing heat to distribute more uniformly across the substrate plane. This periodic on-off pattern prevents localized overheating while maintaining overall heating efficiency, thereby resolving the contradiction between processing capability and temperature uniformity.
Solution Approach 2:
The patent implements preliminary action by conducting a pre-heating phase before the main microwave irradiation. During this preliminary phase, the substrate is gradually heated to a lower temperature first, establishing a more uniform initial temperature distribution. This preparatory heating step prevents sudden thermal shocks and non-uniform temperature gradients that would otherwise cause warpage or cracking during subsequent high-power irradiation.
2Speed
If microwave power is increased to improve heating efficiency, then heating speed is improved, but temperature distribution becomes more non-uniform causing substrate deformation
Solution Approach 1:
The patent uses periodic action to modulate microwave power delivery by alternating between high-power irradiation periods and pause periods. During high-power periods, rapid heating occurs, while during pause periods, heat redistributes uniformly across the substrate. This cycling approach maintains high overall heating speed while preventing the non-uniform temperature distribution that would cause deformation, thus resolving the contradiction between heating speed and shape stability.
Solution Approach 2:
The patent applies dynamics by making the microwave power delivery dynamic rather than static. The system continuously adjusts microwave power levels between high and low states, and between irradiation and pause periods, adapting the heating process to the substrate's real-time thermal state. This dynamic control enables fast heating while maintaining shape stability through real-time adjustment of energy input.
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
The apparatus effectively suppresses substrate warpage and cracking by promoting uniform temperature distribution and heat conduction, allowing for efficient processing of high-density substrates with complex patterns.
Implementation Method 1
a microwave oscillator configured to supply microwaves to the process chamber
Data Source
AI summary
There is provided a technique, which includes: a process chamber where a substrate is processed; a microwave oscillator configured to supply microwaves to the process chamber; and a controller configured to be capable of controlling the microwave oscillator to perform: a heating process where the substrate is heated with a first microwave, among the supplied microwaves, supplied at a first microwave power so that a process of supplying the first microwave during a supply time and a process of stopping the supply of the first microwave during a stop time shorter than the supply time are performed a predetermined number of times or for a first predetermined time; and a modifying process in which the substrate is supplied with a second microwave, among the supplied microwaves, at a second microwave power higher than the first microwave power for a second predetermined time while maintaining the second microwave power.