Induction Reflow Bonding for Fast Semiconductor Bump Joining
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Solution Overview
Problem
Existing semiconductor reflow apparatuses face inefficiencies in heating conductive bumps and applying pressure during the reflow process, leading to potential defects in semiconductor packages due to prolonged exposure to high temperatures.
Innovation Solution
A semiconductor reflow apparatus incorporating a conveyor, a pickup tool, and an induction heating coil that generates a magnetic field to heat conductive bumps through eddy currents while applying vertical pressure, ensuring efficient bonding of chip dies to a package substrate.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional heating methods are used to melt conductive bumps, then the bumps can be bonded to the substrate, but the heating time is prolonged causing defects in semiconductor packages
Solution Approach 1:
The patent replaces conventional thermal conduction heating with induction heating technology. The induction heating coil generates a magnetic field that directly induces eddy currents in the conductive bumps, converting electromagnetic energy directly into heat at the target location. This eliminates the need for prolonged thermal conduction through the substrate, significantly reducing heating time while maintaining bonding quality.
Solution Approach 2:
The induction heating coil applies periodic alternating current to generate oscillating magnetic fields. This periodic action creates continuous eddy currents in the conductive bumps, enabling rapid and controlled heating. The periodic nature of the electromagnetic field allows for precise control of the heating process, achieving melting and bonding in a short duration without causing thermal damage to surrounding components.
2Manufacturing precision
If conventional heating is applied without pressure, then the process is simple, but bonding quality deteriorates due to insufficient contact between chip dies and substrate
Solution Approach 1:
The patent combines the induction heating function with a pressing mechanism into an integrated assembly. The pressing member applies vertical pressure to ensure intimate contact between the chip dies and substrate during the induction heating process. This merging of heating and pressing functions achieves high-quality bonding without requiring separate complex processing steps, as the pressure application is synchronized with the rapid heating cycle.
3Strength
If high temperature is applied for extended duration to ensure bonding, then bonding strength increases, but thermal damage and defects occur in semiconductor packages
Solution Approach 1:
The patent replaces prolonged thermal conduction with direct electromagnetic induction heating. The induction heating coil generates a magnetic field that penetrates the substrate and directly induces eddy currents in the conductive bumps, heating them rapidly to melting temperature. This direct heating method achieves the necessary bonding strength in seconds, preventing thermal damage to temperature-sensitive semiconductor components that would occur with extended heating.
Solution Approach 2:
The patent fundamentally changes the heating parameter from slow thermal conduction to rapid electromagnetic heating. By using induction heating, the temperature rise rate increases dramatically, allowing the conductive bumps to reach melting temperature almost instantly. This parameter change enables the bonding process to complete before heat can diffuse to and damage surrounding semiconductor structures, maintaining both bonding strength and component integrity.
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
The apparatus efficiently melts conductive bumps in a short time, reducing defects by minimizing exposure to high temperatures and enhancing the quality of the reflow process.
Implementation Method 1
an induction heating coil configured to heat the plurality of bumps through eddy current
Implementation Method 2
an induction heating coil configured to generate a magnetic field in a direction passing through a surface of the conveyor
Data Source
AI summary
A semiconductor reflow apparatus includes a conveyor comprising a laterally moveable surface configured to move in a first direction, a pickup tool including a head disposed above the conveyor, and an induction heating coil configured to generate a magnetic field in a direction passing through a surface of the conveyor, wherein the pickup tool is further configured to move the head in a vertical direction toward the conveyor.