Benefits of Soldering with Vacuum Profiles

Estimated reading time: 4 minutes

Where modern vacuum systems are concerned, we no longer speak of simply evacuating the atmosphere, but rather the user is provided with the option of influencing the gradient at which the vacuum is generated and adjusting dwell time at a specified pressure. This provides, above all, sensitive components and volatile flux ingredients with the opportunity of adapting to prevailing ambient conditions. Damage to components or solder splashing may otherwise occur. However, this type of vacuum profiling must not be seen a separate step—it’s available for the entire duration of the soldering process. As a result, pressure can be adjusted in addition to the temperature profile, making it possible to fulfill various requirements. Moisture absorbed by the solder paste can be removed before soldering, or all of the process gas can be exchanged (i.e., at 160°C, in order to remove residues that have evaporated out of either the PCB material or the solder paste, and to assure that they don’t condense onto sensitive components (e.g., optics) during the cooling process). The CondensoX provides users with greatest possible flexibility in this respect, allowing them to respond to a vast variety of tasks and to influence the PCB assembly manufacturing process in a targeted and reproducible fashion.

Where modern vacuum systems are concerned, we no longer speak of simply evacuating the atmosphere, but rather the user is provided with the option of influencing the gradient at which the vacuum is generated and adjusting dwell time at a specified pressure. This provides, above all, sensitive components and volatile flux ingredients with the opportunity of adapting to prevailing ambient conditions. Damage to components or solder splashing may otherwise occur. However, this type of vacuum profiling must not be seen a separate step—it’s available for the entire duration of the soldering process. As a result, pressure can be adjusted in addition to the temperature profile, making it possible to fulfill various requirements. Moisture absorbed by the solder paste can be removed before soldering, or all of the process gas can be exchanged (i.e., at 160°C, in order to remove residues that have evaporated out of either the PCB material or the solder paste, and to assure that they don’t condense onto sensitive components (e.g., optics) during the cooling process). The CondensoX provides users with greatest possible flexibility in this respect, allowing them to respond to a vast variety of tasks and to influence the PCB assembly manufacturing process in a targeted and reproducible fashion.

The utilized vacuum and temperature profile is shown in Figure 4, with which BGA and QFN (BTC) components were soldered in the CondensoX during the course of the case study. Not only were the PCBs soldered with and without vacuum for the study—stencil apertures were varied as well. The goal was to demonstrate the extent to which void results can be influenced for both soldering processes. 

Helmut Öttl is head of application and product management at Rehm Thermal Systems.

ABOUT REHM THERMAL SYSTEMS:

Today, over 450 creative minds work for Rehm worldwide and the product portfolio continues to grow. In addition to reflow soldering systems offering convection, condensation and vacuum processes, this also includes drying and coating systems, cold and hot function testing systems and systems for metallizing solar cells. Rehm has also gained an international reputation for developing individual special systems matched specifically to customer requirements. With production facilities in Germany and China and 26 representations in 24 countries, the company is an established entity and technological leader in the production of efficient machines for the economically viable production of electronic modules.

Visit Rehm Thermal Systems online for more information.

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