Substrate Heating Device Sealing for Gas Control
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Solution Overview
Problem
Existing Rapid Thermal Processor devices face challenges in controlling the environment of the substrate during crystallization, leading to gas losses and contamination, which affect the accuracy of the temperature profile and the recrystallization process.
Innovation Solution
The device incorporates sealing means with flanges and a spring space to prevent gas escape, allowing precise control of the process gas environment, and includes adjustable gas stream control units to maintain desired pressure differences, ensuring efficient sealing and improved recrystallization.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the substrate is placed in a box for transport through the process chamber, then the substrate environment can be maintained, but the box adds thermal capacity that prevents the substrate from following the desired temperature profile
Solution Approach 1:
The patent removes the box from the system entirely. Instead of transporting the substrate in a box, the substrate is placed directly on transport rollers that move it through the process chamber. This extraction eliminates the thermal capacity problem while maintaining environment control through direct sealing of the process chamber around the substrate.
Solution Approach 2:
Instead of using a box to contain and protect the substrate environment, the patent inverts the approach by creating a sealed process chamber environment that directly accommodates the substrate on open rollers. The sealing is achieved through flanges and seals at the chamber openings rather than through an enclosing box structure.
2Loss of substance
If sealing means are added to prevent process gas escape, then gas loss is reduced, but device complexity increases
Solution Approach 1:
The patent employs flexible sealing elements including O-rings and lip seals that can deform to accommodate the passage of substrates and transport rollers while maintaining the seal. These thin film-like sealing components prevent gas escape without requiring complex rigid sealing structures, thus reducing device complexity while effectively preventing process gas loss.
3Reliability
If flanges are pressed against inner walls to prevent gas escape, then sealing is improved, but dimensional changes from thermal expansion cannot be compensated
Solution Approach 1:
The patent incorporates dynamic sealing solutions including spring-loaded flanges and flexible sealing elements that can adjust their position and pressure in response to thermal expansion and contraction. The springs provide continuous contact force while allowing movement, and the flexible seals can deform to maintain sealing effectiveness despite dimensional changes in the chamber components.
Solution Approach 2:
The patent explicitly accounts for thermal expansion by designing the sealing system with components that can accommodate dimensional changes. The flanges and sealing elements are positioned and dimensioned to allow for expansion gaps, and the spring mechanisms are pre-loaded to maintain sealing pressure throughout the temperature range of operation.
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 solution enhances the control over the substrate environment, reducing gas losses and contamination, allowing for better adherence to the temperature profile and improved recrystallization of materials, such as copper, indium, and selenium, used in solar cells.
Implementation Method 1
a) a spring element (30) which is arranged in the passage space for exerting a first force by means of an axially directed side of the first flange (25) on a part of the passage space around the first passage opening (21) and/or a second force by means of an axially directed side of the second flange (26) on a part of the passage space around the second passage opening (22)
Implementation Method 2
The known device may comprise several process chambers, each of which is subjected to a specific temperature profile by heating these process chambers by means of heating elements
Implementation Method 3
an evaporator (16) which is coupled to the first process chamber (3) via an inlet (17) for evaporating a material which is to be applied to the substrate (12), for example selenium
Implementation Method 4
a vapour transport deposition device (42) which is positioned in front of the at least first process chamber (4) with respect to a transport direction of the substrate (12)
Implementation Method 5
The device furthermore comprises transport rollers (15) which are arranged in the first process chamber (3) for transporting the substrate (12) through the first process chamber (3)
Data Source
Figure 1
Figure 2~4
Figure 5~6
AI summary
The invention relates to device (1) for heating a substrate (12) according to a predetermined temperature profile for crystallizing a material on the substrate comprising: a housing (2), at least a process chamber (3) which is situated inside the housing and which is provided with a first and second opening (6,7) for passing through a substrate, an inlet (17) for introducing a process gas which comprises the material in a vapour phase into the first process chamber, at least two transport rollers (15) for transporting the substrate into the process chamber (3), wherein the transport rollers are attached to the housing (2) so as to be rotatable. The device is furthermore provided with passage spaces (20,25) for preventing the escape of process gas from the process chamber to a space between the process chamber (3) and the housing (2), which are situated near respective ends of the transport rollers (15) in the process chamber (3), wherein the respective passage spaces (20) are provided with a first passage opening (21) on an inner wall (23) of the process chamber (3), a second passage opening (22) on an outer wall (24) of the process chamber (3) and a first flange (25) which is fixed around the transport roller (15).