Dual Nozzle Substrate Processing for Film Thickness Uniformity
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Solution Overview
Problem
Existing semiconductor manufacturing processes face challenges in controlling the in-plane film thickness distribution of films formed on substrates, particularly on pattern wafers with large surface areas, where precursor gases are unevenly consumed, leading to center concave distributions and difficulties in achieving flat or center convex distributions.
Innovation Solution
A method involving a substrate processing apparatus with multiple nozzles that alternately supply a precursor gas and a reactant gas, with specific flow rate control strategies, including initial low flow rates of an inert gas to suppress dilution and subsequent higher flow rates to enhance central coverage, allowing for precise control of film thickness distribution.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If a precursor gas is supplied to form a film on a substrate, then film formation is achieved, but the in-plane film thickness distribution becomes non-uniform (center concave distribution) due to uneven precursor consumption across the wafer surface
Solution Approach 1:
The film formation process is divided into multiple discrete steps: precursor supply step, inert gas supply step, and reactant supply step. The inert gas supply is further segmented into two flow rate phases (first flow rate during precursor supply, second flow rate after precursor supply). This segmentation allows independent optimization of each step to achieve uniform film thickness distribution.
Solution Approach 2:
An inert gas is supplied from the second nozzle before and during the precursor supply to pre-establish a controlled gas environment. This preliminary action prevents premature precursor consumption and ensures uniform precursor distribution across the wafer surface before the actual film formation begins.
2Productivity
If the precursor supply is increased to improve film formation rate, then productivity increases, but the in-plane thickness uniformity deteriorates due to enhanced precursor consumption variations
Solution Approach 1:
An inert gas is introduced as an intermediary substance between the precursor gas and the substrate. This intermediary controls the precursor distribution by preventing premature consumption and ensuring uniform delivery across the wafer surface, thereby maintaining thickness uniformity even at higher precursor supply rates that increase productivity.
Solution Approach 2:
The inert gas flow rate is dynamically changed between two phases: first flow rate during precursor supply to maintain uniform distribution, and second flow rate after precursor supply to control reaction environment. This parameter change allows optimization of both film formation rate and thickness uniformity.
3Device complexity
If a single nozzle is used to supply both precursor and reactant, then device complexity is reduced, but the ability to control in-plane film thickness distribution is compromised
Solution Approach 1:
The gas supply function is segmented across two separate nozzles: the first nozzle supplies precursor gas and the second nozzle supplies inert gas and reactant gas. This functional segmentation allows independent control of gas flow rates and timing, enabling precise control of film thickness distribution without requiring a single complex multi-functional nozzle.
4Manufacturing precision
If the inert gas flow rate is increased to improve central coverage, then in-plane thickness uniformity improves, but precursor dilution increases reducing film formation rate
Solution Approach 1:
The inert gas flow rate is made dynamic with two distinct phases: first flow rate during precursor supply to ensure uniform distribution without excessive dilution, and second flow rate after precursor supply to enhance central coverage and control the reaction environment. This dynamic adjustment optimizes both uniformity and film formation rate.
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 enables the formation of films with controlled in-plane thickness distributions, achieving flat or center convex distributions on both bare and pattern wafers, improving film formation rates and productivity while maintaining uniformity across wafer surfaces.
Implementation Method 1
forming a first layer by supplying a precursor to the substrate from a first nozzle
Implementation Method 2
forming a second layer by supplying a reactant to the substrate from a second nozzle different from the first nozzle to thereby modify the first layer
Implementation Method 3
supplying an inert gas from the second nozzle at a first flow rate smaller than a flow rate of the precursor
Data Source
AI summary
A method of manufacturing a semiconductor device includes forming a film on a substrate by performing a cycle a predetermined number of times. The cycle includes non-simultaneously performing (a) forming a first layer by supplying a precursor to the substrate from a first nozzle and (b) forming a second layer by supplying a reactant to the substrate from a second nozzle different from the first nozzle to thereby modify the first layer. The act (a) includes sequentially performing (a-1) supplying an inert gas from the second nozzle at a first flow rate smaller than a flow rate of the precursor in a state in which the precursor is supplied from the first nozzle and (a-2) supplying an inert gas from the second nozzle at a second flow rate larger than the flow rate of the precursor in a state in which the precursor is supplied from the first nozzle.