Laser Soldering of Chip Substrates to Reduce Warpage
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Solution Overview
Problem
Existing soldering methods using high-temperature heat sources like ovens and IR lamps result in long processing times, leading to thermal deformation and package warpage due to CTE differences between chips and substrates, and cause thermal shock and uneven solder processing temperatures.
Innovation Solution
A laser-based soldering method that includes preheating the substrate and solder, using masks to protect the chip and edge, and rapid laser irradiation to attach solder within seconds, reducing process time and preventing defects.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If high-temperature heat sources like ovens and IR lamps are used for soldering, then solder melting and attachment can be achieved, but processing time becomes long and thermal deformation occurs
Solution Approach 1:
The patent replaces conventional thermal conduction heating (ovens, IR lamps) with laser beam heating. The laser directly irradiates the solder joint area, enabling rapid localized heating and melting of solder within seconds, dramatically reducing processing time while maintaining attachment quality.
Solution Approach 2:
The laser heating method applies heat locally only to the solder joint area rather than heating the entire substrate uniformly. This localized heating approach achieves solder melting quickly while minimizing thermal exposure to other components, reducing thermal deformation and processing time.
2Manufacturing precision
If high-temperature heat sources are applied to the entire substrate, then solder melting is achieved, but package warpage occurs due to CTE differences
Solution Approach 1:
The laser heating method applies heat locally only to the solder joint area rather than heating the entire substrate uniformly. This localized heating approach achieves solder melting quickly while minimizing thermal exposure to other components, reducing thermal deformation and processing time.
Solution Approach 2:
The heating process is segmented into localized zones using laser irradiation. Only the specific solder joint region receives high-intensity heating, while other areas remain at lower temperatures, preventing uniform thermal expansion and warpage across the substrate.
3Manufacturing precision
If conventional heating methods are used, then solder processing is achieved, but thermal shock occurs on the chip and substrate
Solution Approach 1:
The patent replaces conventional thermal conduction heating (ovens, IR lamps) with laser beam heating. The laser directly irradiates the solder joint area, enabling rapid localized heating and melting of solder within seconds, dramatically reducing processing time while maintaining attachment quality.
Solution Approach 2:
The laser heating method rapidly heats the solder joint area through in a very short time (within seconds), quickly passing through the heating phase before thermal shock can propagate to the chip and substrate, thereby reducing thermal shock damage.
4Manufacturing precision
If conventional heating methods are used, then solder processing is achieved, but uneven solder processing temperature occurs
Solution Approach 1:
The patent replaces conventional thermal conduction heating (ovens, IR lamps) with laser beam heating. The laser directly irradiates the solder joint area, enabling rapid localized heating and melting of solder within seconds, dramatically reducing processing time while maintaining attachment quality.
Solution Approach 2:
The system uses a camera to capture images of the solder joint area during laser heating and feeds this visual information back to a controller. The controller adjusts laser power and heating parameters in real-time based on the captured images, ensuring uniform temperature distribution and preventing overheating or underheating.
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
Reduces warpage and thermal shock by minimizing thermal expansion differences, shortens the process time, and prevents defects from uneven solder temperatures.
Implementation Method 1
an attachment process in which the upper portion of the substrate is irradiated with the laser so that the solder is melted and attached to the upper portion of the substrate
Implementation Method 2
a preheating process in which the substrate and the solder are preheated while the substrate is moved together with the substrate fixing member
Data Source
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AI summary
Proposed is a solder soldering method using a laser. The solder soldering method performs solder soldering within a few seconds by using the laser so that warpage occurring due to a difference in a coefficient of thermal expansion between a chip and a substrate may be reduced, thermal shock that occurs on the chip and the substrate may be reduced, an entire process time may be reduced, and defects due to an uneven solder processing temperature may be reduced. The solder soldering method includes a supplying process in which a substrate having solder is supplied to a substrate fixing member, a preheating process in which the substrate and the solder are preheated, an attachment process in which the substrate is irradiated with the laser and the solder is melted and attached to the substrate, and a discharging process in which the substrate is moved to a tray.