Heat Insulating Member Through-Hole Wafer Temperature Uniformity
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Solution Overview
Problem
In semiconductor manufacturing, existing film forming processes using vertical heat treatment apparatuses face challenges in achieving uniform film thickness distribution across wafers, particularly when forming silicon films with SiH4 gas, as the film thickness in the peripheral portions is often smaller than in the central portions due to inadequate heating and decomposition of the gas, leading to a trade-off between film shape and uniformity.
Innovation Solution
A film forming apparatus and method that includes a heat insulating member with a through-hole positioned to overlap with the central portions of substrates, thermally insulating the substrate arrangement region from above or below, which adjusts the temperature distribution and enhances gas decomposition, thereby increasing film thickness in peripheral areas and maintaining uniformity between wafers.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If dummy wafers are mounted on the lower side of the wafer group to thermally insulate the substrates, then the uniformity of film thickness between wafers is improved, but the film thickness in the peripheral portions becomes smaller than in the central portions
Solution Approach 1:
The patent applies local quality by providing heat insulating members only at specific locations (above or below the wafer group at peripheral regions) rather than uniformly across the entire wafer boat. This localized insulation approach creates a temperature distribution that compensates for the lower temperature at peripheral portions, thereby improving film thickness uniformity in those regions while maintaining the desired film shape.
Solution Approach 2:
The heat insulating members act as intermediary elements between the heating source and the wafers. These insulating members (made of materials like quartz or alumina) mediate the heat transfer process by reducing heat loss at peripheral regions, thereby adjusting the temperature distribution to achieve both uniform film thickness and proper film shape.
2Manufacturing precision
If SiH4 gas is supplied from the lower side to form silicon film, then film formation is achieved, but the film thickness in peripheral portions becomes smaller due to insufficient heating and decomposition
Solution Approach 1:
The patent addresses the temperature distribution issue by applying local quality through strategically positioned heat insulating members. These members are placed above or below the wafer group at peripheral regions where temperature is lower, creating a localized temperature increase that ensures sufficient SiH4 gas decomposition and film formation in those critical areas.
Solution Approach 2:
The patent employs parameter changes by modifying the thermal environment parameters (temperature distribution) through the introduction of heat insulating members. This changes the temperature parameter locally at peripheral regions, enabling adequate gas decomposition and film thickness control without altering the overall film formation process parameters.
3Manufacturing precision
If heat insulating members are provided above or below the substrate arrangement region, then temperature distribution is adjusted and peripheral film thickness is increased, but the device complexity increases
Solution Approach 1:
The patent minimizes device complexity by applying local quality - heat insulating members are provided only at specific locations (above or below the wafer group at peripheral regions) rather than throughout the entire structure. This selective placement achieves the desired temperature adjustment and film thickness control while keeping the overall structure simple and manageable.
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 solution effectively adjusts the film thickness distribution in the plane of the substrates, ensuring that the film thickness in the peripheral portions is larger than in the central portions, while maintaining the uniformity of film thickness between wafers, thus addressing the trade-off between film shape and uniformity.
Implementation Method 1
a first heat insulating member provided above or below an arrangement region of the plurality of substrates in the substrate holder so as to overlap with the arrangement region and configured to thermally insulate the arrangement region from an upper region above the arrangement region or to thermally insulate the arrangement region from a lower region below the arrangement region
Implementation Method 2
a through-hole provided in the first heat insulating member at a position overlapping with central portions of the substrates so as to adjust a temperature distribution in a plane of each of the substrates held in a vicinity of the first heat insulating member
Implementation Method 3
by heating the substrates with a heating part in a state in which the substrates are held in a shelf shape by a substrate holder
Data Source
AI summary
There is provided a film forming apparatus for performing a film forming process on substrates by heating the substrates while the substrates are held in a shelf shape by a substrate holder in a vertical reaction container. The film forming apparatus includes: an exhaust part configured to evacuate the reaction container; a gas supply part configured to supply a film forming gas into the reaction container; a heat insulating member provided above or below an arrangement region of the substrates to overlap with the arrangement region and configured to thermally insulate the arrangement region from an upper region above the arrangement region or a lower region below the arrangement region; and a through-hole provided in the heat insulating member at a position overlapping with central portions of the substrates to adjust a temperature distribution in a plane of each substrate held near the heat insulating member.