Laser Contact Pad Bonding to Prevent PCB Warping
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Solution Overview
Problem
Traditional reflow bonding processes in electronic device manufacturing often result in circuit board warping and damage to electronic elements due to high-temperature soldering, which compromises structural reliability.
Innovation Solution
A manufacturing method involving a circuit substrate with a base material, a first metal layer, and a contact pad, where a conductive bump is used to bond an electronic element, and local heating with a laser is applied to the contact pad from the opposite side of the substrate to reduce thermal effects during bonding.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If traditional reflow oven heating is used to bond the contact pad, then bonding strength is achieved, but circuit board warping and electronic element damage occur due to high-temperature exposure
Solution Approach 1:
The patent applies local quality by using laser heating to locally heat only the contact pad area where bonding is required, rather than heating the entire circuit board. This localized heating approach achieves the necessary bonding temperature at the specific location while keeping the rest of the electronic elements and circuit board at lower temperatures, thus preventing thermal damage to temperature-sensitive components.
Solution Approach 2:
The patent replaces the traditional mechanical reflow oven heating system with a laser heating system. Instead of using a large oven to heat the entire assembly, a focused laser beam is used to deliver precise thermal energy only to the contact pad area, enabling bonding without subjecting the entire electronic device to high temperatures that cause warping and damage.
2Reliability
If high-temperature reflow soldering is applied to all members, then bonding reliability is improved, but circuit board warping occurs
Solution Approach 1:
The patent implements local quality by concentrating the heating action only on the contact pad region where bonding is needed. The laser heating method allows the contact pad to reach the required bonding temperature while the surrounding circuit board areas remain at lower temperatures, preventing the thermal expansion and warping that occur when the entire board is heated uniformly in traditional reflow processes.
Solution Approach 2:
The patent applies segmentation by dividing the heating process into a localized zone (contact pad) rather than heating the entire circuit board. This spatial segmentation of the thermal process allows bonding to occur at the specific location without subjecting the rest of the circuit board to high temperatures that would cause warping and deformation.
3Strength
If conventional reflow bonding process is used, then bonding is achieved, but electronic elements are damaged due to inability to withstand high temperature
Solution Approach 1:
The patent uses local quality by applying laser heating specifically to the contact pad area where bonding is required, rather than heating the entire electronic assembly. This localized thermal treatment allows the contact pad to reach bonding temperatures while keeping temperature-sensitive electronic elements at lower temperatures throughout the process, preventing damage to components that cannot withstand high temperatures.
Solution Approach 2:
The patent replaces the conventional reflow oven mechanical heating system with a laser-based heating system. This substitution enables precise control of the heating zone, allowing bonding to occur at the contact pad without exposing the entire electronic device to the high temperatures that would damage sensitive electronic elements.
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 effectively minimizes thermal stress and damage to electronic components, enhancing the structural reliability of the electronic device by localized heating instead of full reflow oven heating.
Implementation Method 1
A laser is applied to an area of the second side of the base material corresponding to the contact pad
Data Source
AI summary
An electronic device and a manufacturing method thereof are provided. The manufacturing method of the electronic device includes forming a circuit substrate. Forming the circuit substrate includes providing a base material, wherein the base material has a first side and a second side opposite to each other. A contact pad is formed on the first side. An electronic element is provided. A conductive bump is formed on the contact pad, wherein the electronic element is bonded onto the circuit substrate via the conductive bump. A laser is applied to an area of the second side of the base material corresponding to the contact pad.