Semiconductor Package Laser Bonding Warpage Reduction
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Solution Overview
Problem
Semiconductor packages face warpage issues during bonding processes due to the vulnerability of flexible substrates to heat, which affects the reliability of the packaging process.
Innovation Solution
A method involving the use of a resin layer with solder and reducing agent granules, where laser irradiation generates heat to remove capsule layers and metal oxide layers, connecting the semiconductor chip to the substrate pad while reducing warpage, and incorporating a curing agent to solidify the base material layer.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a flexible substrate is used in the semiconductor package, then the package can be made more adaptable and flexible, but the substrate becomes vulnerable to heat during the bonding process causing warpage
Solution Approach 1:
A resin layer is introduced as an intermediary material between the semiconductor chip and the flexible substrate. This resin layer acts as a thermal buffer that protects the flexible substrate from direct exposure to high temperatures during laser bonding, thereby preventing warpage while allowing the flexible substrate to maintain its adaptability benefits
2Productivity
If laser irradiation is used for bonding the chip pad to the substrate pad, then the bonding speed and precision are improved, but the heat generated causes warpage of the flexible substrate
Solution Approach 1:
The resin layer serves as a thermal intermediary that absorbs and distributes the heat generated by laser irradiation during bonding. This prevents concentrated heat from causing substrate warpage while maintaining the high bonding speed and precision benefits of laser technology
Solution Approach 2:
The resin layer changes its physical parameters (viscosity, thermal conductivity) in response to controlled heating during the bonding process. Initially, it remains stable during rapid bonding; as temperature increases, it softens to provide thermal buffering, then cures to lock in the bonded structure, thereby managing heat effects at different process stages
3Reliability
If multiple layers (capsule layer, metal oxide layers) need to be removed during bonding, then the bonding reliability is improved, but the process complexity increases
Solution Approach 1:
The resin layer combines multiple functional capabilities into a single material system: it contains encapsulated reducing agents that remove metal oxide layers, provides thermal management during bonding, and offers structural support. This merging of functions reduces process complexity compared to separate treatments for each issue
4Reliability
If the resin layer contains reducing agent granules with capsule layers, then the metal oxide removal is enhanced, but the resin layer structure becomes more complex
Solution Approach 1:
The reducing agent granules are encapsulated within capsule structures that are themselves embedded in the resin layer matrix. This nested arrangement protects the reducing agents until needed, allows controlled release during bonding, and maintains a relatively simple overall resin layer structure despite the complex internal organization of functional components
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 method effectively reduces substrate warpage and enhances the bonding process, improving the reliability and stability of semiconductor packages by using laser-generated heat to remove layers and solidify the resin, ensuring strong connections between chip and substrate.
Implementation Method 1
bonding the chip pad to the substrate pad using laser irradiated to the semiconductor chip
Implementation Method 2
removing the first capsule layer by heat generated from the laser
Implementation Method 3
removing first to third metal oxide layers on the substrate pad, the solder, and the chip pad using the reducing agent granules
Implementation Method 4
connecting the chip pad to the substrate pad
Implementation Method 5
curing the base material layer using the curing agent granules
Data Source
AI summary
Provided is a method of fabricating a semiconductor package. The method includes preparing a package substrate having a substrate pad, and mounting a semiconductor chip on the substrate pad. Mounting the semiconductor chip includes forming a resin layer containing a solder and reducing agent granules having a first capsule layer, between a chip pad of the semiconductor chip and the substrate pad, and bonding the chip pad to the substrate pad using laser irradiated to the semiconductor chip.