Reduced-Pressure Processing Oven for Small-Bump Solder Reflow
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Solution Overview
Problem
Current solder reflow methods using batch thermal reflow systems are inadequate for small solder geometries, as they fail to achieve desirable solder yield due to suboptimal pressure and chemical vapor delivery.
Innovation Solution
A processing oven with a chamber that decreases pressure to between 0.1-50 Torr, uses formic acid vapor and nitrogen to assist in solder reflow, and employs a controlled temperature profile to ensure uniform heating and vapor distribution.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If batch thermal reflow systems are used for solder reflow, then the process can handle larger solder geometries, but solder yield decreases for small solder bumps
Solution Approach 1:
The patent changes the pressure parameter from atmospheric to reduced pressure (0.1-100 Torr) to improve chemical vapor delivery to small solder bumps. This parameter change enables the system to achieve high solder yield for small geometries by allowing chemical vapor to reach all regions of the solder bumps without atmospheric pressure resistance
Solution Approach 2:
The patent uses reduced pressure (vacuum) environment to facilitate chemical vapor delivery. By creating a pressure differential, the system enables chemical vapor to effectively reach and interact with small solder bumps, overcoming the limiting effect of atmospheric pressure on vapor penetration
2Reliability
If atmospheric pressure is used during solder reflow, then the process is simpler to operate, but chemical vapor cannot reach all regions of small solder bumps
Solution Approach 1:
The patent modifies the pressure parameter from atmospheric to reduced pressure range (0.1-100 Torr) to enhance chemical vapor delivery effectiveness. This change allows chemical vapor to penetrate and reach all regions of small solder bumps, improving reflow reliability despite increased operational complexity
3Manufacturing precision
If conventional batch reflow ovens are used, then the equipment is simpler, but precise thermal process control and chemical vapor delivery are not achieved
Solution Approach 1:
The patent implements precise control of temperature and pressure parameters. The system maintains pressure within 0.1-100 Torr while controlling temperature profiles, enabling both precise thermal process control and effective chemical vapor delivery to small solder bumps
Solution Approach 2:
The patent incorporates a vacuum system to maintain reduced pressure environment throughout the reflow process. This pneumatic control mechanism enables consistent chemical vapor delivery and thermal processing, achieving high manufacturing precision despite increased system complexity
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 enhances solder yield by providing precise thermal process control and improved chemical vapor delivery, effectively 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
Formic acid vapor may be admitted into the chamber above the at least one substrate
Implementation Method 3
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 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.