Processing Oven Pressure Control for Small Solder Reflow
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Solution Overview
Problem
Current solder reflow methods using batch thermal ovens are inadequate for small solder geometries due to suboptimal pressure and chemical vapor delivery, leading to reduced yield and precision in thermal process control.
Innovation Solution
A solder reflow oven that operates at reduced pressures (0.1-50 Torr) with controlled temperature profiles and uses formic acid vapor and nitrogen to enhance chemical vapor distribution, ensuring uniform heating and cooling of substrates with precise temperature control.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If atmospheric pressure is used for chemical vapor delivery during solder reflow, then the process is simple to operate, but the chemical vapor cannot effectively reach all regions of small solder bumps, reducing solder yield
Solution Approach 1:
The patent changes the pressure parameter from atmospheric pressure to reduced pressure (vacuum conditions). This parameter change allows chemical vapor to effectively reach all regions of small solder bumps by eliminating atmospheric pressure resistance, thereby improving solder yield while maintaining process effectiveness.
2Manufacturing precision
If batch thermal reflow systems are used for small solder bumps, then the equipment is simple, but the thermal process control precision is insufficient to achieve desirable solder yield
Solution Approach 1:
The patent transitions from static batch processing to dynamic continuous processing. The system continuously adjusts temperature profiles and chemical vapor delivery during the reflow process, enabling precise thermal control for small solder bumps while maintaining high throughput through continuous substrate processing.
3Manufacturing precision
If chemical vapor is introduced at atmospheric pressure, then the equipment configuration is simple, but the vapor delivery effectiveness to small solder geometries is poor
Solution Approach 1:
The patent changes the pressure parameter from atmospheric pressure to reduced pressure (vacuum conditions). This parameter change allows chemical vapor to effectively reach all regions of small solder bumps by eliminating atmospheric pressure resistance, thereby improving solder yield while maintaining process effectiveness.
4Manufacturing precision
If conventional batch reflow ovens are used, then the device complexity is low, but the precision for small solder geometries is insufficient
Solution Approach 1:
The patent transitions from static batch processing to dynamic continuous processing. The system continuously adjusts temperature profiles and chemical vapor delivery during the reflow process, enabling precise thermal control for small solder bumps while maintaining high throughput through continuous substrate processing.
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 improves the yield and precision of solder reflow by ensuring effective chemical vapor coverage and uniform heating, addressing the limitations of traditional batch reflow systems for small solder geometries.
Implementation Method 1
decreasing a pressure of the chamber to a first pressure between about 0.1-50 Torr
Implementation Method 2
the temperature of the at least one substrate may be increased to a first temperature... the temperature of the at least one substrate may be further increased to a second temperature higher than the first temperature
Implementation Method 3
Formic acid vapor may be admitted into the chamber above the at least one substrate
Implementation Method 4
nitrogen is admitted into the chamber below the at least one substrate
Implementation Method 5
the at least one substrate may be cooled
Data Source
AI summary
A method of using a processing oven may include disposing at least one substrate in a chamber of the oven and activating a lamp assembly disposed above them to increase their temperature to a first temperature. A chemical vapor may be admitted into the chamber above the at least one substrate and an inert gas may be admitted into the chamber below the at least one substrate. The temperature of the at least one substrate may then be increased to a second temperature higher than the first temperature and then cooled down.