Amorphous Silicon Film Uniformity via Temperature Gradient Control
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Solution Overview
Problem
Existing film forming methods result in non-uniform amorphous silicon film thickness across substrates, particularly those with recesses, due to differences in incubation time and film formation rate between the central and peripheral regions, leading to deteriorated in-plane uniformity and productivity issues.
Innovation Solution
A film forming method involving a temperature lowering process to create a temperature gradient on the substrate by supplying halogen-free and halogen-containing silicon raw materials, followed by a temperature stabilizing process to maintain a uniform temperature, ensuring consistent nucleation and film formation across the substrate surface.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If substrate spacing is increased to improve in-plane uniformity of film thickness, then film uniformity is improved, but productivity deteriorates due to reduced substrate processing capacity
Solution Approach 1:
The patent changes the temperature parameter during film formation, specifically lowering the substrate temperature to suppress the film formation rate. This parameter change allows uniform film formation without requiring increased substrate spacing, thereby maintaining high substrate processing capacity while improving in-plane uniformity of film thickness
Solution Approach 2:
The patent performs preliminary heating of the substrate before film formation to ensure uniform temperature distribution across the substrate surface. This preliminary action prevents temperature gradients that would cause non-uniform film thickness, eliminating the need to increase substrate spacing and preserving productivity
2Manufacturing precision
If substrate temperature is lowered to suppress film formation rate and improve uniformity, then in-plane uniformity is improved, but incubation time difference between central and peripheral regions increases
Solution Approach 1:
The patent performs preliminary heating of the substrate to a higher temperature before film formation to reduce the incubation time difference between central and peripheral regions. This preliminary action ensures that nucleation occurs uniformly across the substrate surface, preventing the incubation time difference that would otherwise increase when substrate temperature is lowered
Solution Approach 2:
The patent uses periodic temperature control with two distinct phases: a preliminary heating phase to reduce incubation time difference, followed by a film formation phase at lower temperature to suppress film formation rate and improve uniformity. This periodic action resolves the contradiction between uniformity and incubation time difference
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 reduces the difference in incubation time and improves the in-plane uniformity of film thickness, enhancing productivity without increasing substrate spacing, thus achieving more uniform and efficient amorphous silicon film formation.
Implementation Method 1
supplying a halogen-free silicon raw material gas and a halogen-containing silicon raw material gas into a processing container
Implementation Method 2
lowering a temperature of a substrate accommodated in the processing container from a first temperature to a second temperature
Data Source
AI summary
There is provided a film forming method including: supplying a halogen-free silicon raw material gas and a halogen-containing silicon raw material gas into a processing container while lowering a temperature of a substrate accommodated in the processing container from a first temperature to a second temperature in a temperature lowering process; and supplying the halogen-free silicon raw material gas and the halogen-containing silicon raw material gas into the processing container while maintaining the temperature of the substrate at a third temperature in a temperature stabilizing process, that occurs after the temperature lowering process.