Method for producing a high-temperature resistant lead free solder joint, and high-temperature-resistant lead-free solder joint

A method for creating a high-temperature-resistant, lead-free solder joint between a printed circuit board and a component, the method comprising:

• providing a lead-free solder preform, wherein the lead-free solder preform includes a composite material including a first composite component arranged in layers;
• attaching the solder preform to a solderable surface of the printed circuit board such that the layers of the first composite component are parallel to the solderable surface;
• applying the component to the solder preform attached to the solderable surface, the component having a solderable first surface facing the solder preform;
• and
• soldering the component to the solder preform in a hot-bar selective soldering process, the soldering including:
• pressing a bar onto a second surface of the component facing away from the solder preform;
• flowing an electric current through the bar until a predefined soldering temperature is reached in the bar, wherein at the predefined soldering temperature a first surface of the solder preform facing away from the solderable surface is soldered to the solderable first surface of the component facing the solder preform and wherein intermetallic phases are formed from the layers of the first composite component;
• and
• moving the bar away from the component.

A high-temperature-resistant, lead-free solder joint, comprising:

• a component;
• a printed circuit board;
• and
• a lead-free solder preform including a composite material including a first composite component arranged in layers,
• wherein the solder joint is made by:
• attaching the solder preform to a solderable surface of the printed circuit board such that the layers of the first composite component are parallel to the solderable surface;
• applying the component to the solder preform attached to the solderable surface, the component having a solderable first surface facing the solder preform;
• and
• soldering the component to the solder preform in a hot-bar selective soldering process, the soldering including:
• pressing a bar onto a second surface of the component facing away from the solder preform;
• flowing an electric current through the bar until a predefined soldering temperature is reached in the bar, wherein at the predefined soldering temperature a first surface of the solder preform facing away from the solderable surface is soldered to the solderable first surface of the component facing the solder preform and wherein intermetallic phases are formed from the layers of the first composite component;
• and
• moving the bar away from the component.

A field device of automation technology for determining and/or monitoring the process variable of a medium, comprising:

• an electronic unit which includes at least one printed circuit board having electrical and/or electronic components soldered thereon, wherein a solder joint of at least one of the electrical and/or electronic components is a high-temperature-resistant, lead-free solder joint, including:
• the at least one electrical and/or electronic component;
• the at least one printed circuit board;
• and
• a lead-free solder preform including a composite material including a first composite component arranged in layers,
• wherein the solder joint is made by:
• attaching the solder preform to a solderable surface of the printed circuit board such that the layers of the first composite component are parallel to the solderable surface;
• applying the component to the solder preform attached to the solderable surface, the component having a solderable first surface facing the solder preform;
• and
• soldering the component to the solder preform in a hot-bar selective soldering process, the soldering including:
• pressing a bar onto a second surface of the component facing away from the solder preform;
• flowing an electric current through the bar until a predefined soldering temperature is reached in the bar, wherein at the predefined soldering temperature a first surface of the solder preform facing away from the solderable surface is soldered to the solderable first surface of the component facing the solder preform and wherein intermetallic phases are formed from the layers of the first composite component;
• and
• moving the bar away from the component.