Substrate Preheating Gas Sequence to Suppress Wafer Warping
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Solution Overview
Problem
High-temperature substrate processing in film forming apparatuses often leads to substrate warping, causing misalignment and particle generation, and existing preheating methods are inefficient in preventing warping while maintaining productivity.
Innovation Solution
A substrate processing method involving a two-step preheating process using different gases, where N2 gas is initially supplied for the first preheating, followed by NH3 gas, and then SiH4 gas, to control pressure and temperature, thereby reducing warping and shortening preheating time.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If substrates are heated rapidly to improve productivity, then processing speed is improved, but substrate warping occurs
Solution Approach 1:
The heating process is divided into multiple stages: initial rapid heating phase followed by a controlled cooling phase, and then gradual heating to the target temperature. This segmentation allows the substrate to be heated quickly initially while preventing warping through subsequent controlled temperature adjustments.
Solution Approach 2:
The heating process employs periodic temperature adjustments with heating and cooling cycles. The substrate undergoes repeated heating and cooling phases that allow thermal stress to be managed periodically, preventing cumulative warping while achieving the target temperature efficiently.
2Shape
If preheating time is extended to prevent warping, then substrate shape stability is improved, but processing time increases
Solution Approach 1:
The substrate undergoes preliminary heating to a lower temperature before the main heating phase. This preliminary action prepares the substrate for subsequent rapid heating by reducing thermal stress, allowing the main heating to proceed faster without causing warping.
Solution Approach 2:
The heating process dynamically adjusts temperature parameters through multiple phases. The temperature profile changes from rapid initial heating to controlled intermediate cooling, then to gradual heating toward the target, optimizing both time and shape stability through parameter variation.
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 effectively suppresses substrate warping while significantly reducing preheating time, improving productivity and maintaining film quality, as demonstrated by the use of inert gases like N2, He, and Ar which ensure uniform heating and prevent warping.
Implementation Method 1
the substrate is sufficiently heated by a heater in a stage on which the substrate is placed
Implementation Method 2
gradually heating a substrate with radiant heat from a heater
Implementation Method 3
heating the target substrate with a heater by supplying a first gas into the processing container
Data Source
AI summary
The present disclosure provides a substrate processing method including: a preparation process of placing a target substrate on a stage within a processing container; a first heating process of supplying a first gas into the processing container and heating the target substrate with a heater; a second heating process of stopping the supply of the first gas, supplying a second gas different from the first gas, and heating the target substrate with the heater; and a processing process of processing the target substrate by supplying the second gas and a third gas.