Semiconductor Chip Sintering Paste for Reliable Carrier Attachment
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Solution Overview
Problem
Current methods for fabricating electronic devices with semiconductor chips face challenges in efficiently attaching and electrically coupling these chips to carriers, particularly in achieving strong, reliable connections with minimal mechanical stress and oxidation, while maintaining thermal conductivity and scalability.
Innovation Solution
A method involving the application of a paste with electrically conductive particles, which are sintered onto a carrier, forming a solid layer that securely attaches and electrically couples the semiconductor chip, using a controlled temperature process to prevent oxidation and reduce mechanical stress, and incorporating a mold material for encapsulation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional methods are used to attach semiconductor chips to carriers, then electrical coupling is achieved, but mechanical stress and oxidation occur reducing connection reliability
Solution Approach 1:
The invention changes the physical and chemical parameters of the attachment process by using sintering at controlled temperatures (e.g., 200-400°C for AuSn, 600-800°C for Ag) instead of conventional high-temperature reflow soldering. This parameter change reduces mechanical stress on the chip-carrier connection while preventing oxidation through controlled atmosphere or material selection, thereby improving connection reliability
Solution Approach 2:
The invention employs composite materials in the form of electrically conductive pastes containing metal particles (Au, Ag, Cu, Al) combined with metallization layers (Ni, Pd, Pt) on both the chip and carrier surfaces. This composite material approach creates a multi-layered attachment structure that simultaneously provides electrical conductivity, mechanical strength, stress distribution, and oxidation resistance, resolving the contradiction between reliability and harmful factors
2Strength
If high temperature processes are used for attaching chips, then strong bonds are formed, but thermal damage and oxidation occur
Solution Approach 1:
The invention optimizes the temperature parameter by establishing specific sintering temperature ranges (200-400°C for AuSn, 600-800°C for Ag) that are lower than conventional reflow soldering temperatures. This parameter change achieves sufficient bond strength while avoiding thermal damage to the semiconductor chip and preventing oxidation through controlled processing conditions
Solution Approach 2:
The invention employs inert or controlled atmosphere conditions during the sintering process to prevent oxidation of the metal particles and metallization layers. This may involve using inert gases (nitrogen, argon) or vacuum environments, or selecting oxidation-resistant materials, thereby achieving strong bonds without oxidative degradation
3Ease of manufacture
If traditional soldering methods are used, then electrical coupling is achieved, but process complexity and oxidation control requirements increase
Solution Approach 1:
The invention extracts and eliminates the flux material commonly used in traditional soldering processes. By using sintering of electrically conductive particles without flux, the process simplifies manufacturing while reducing oxidation control requirements, as fluxless sintering avoids the complex chemistry and residue management associated with conventional soldering
Solution Approach 2:
The invention replaces the chemical-mechanical soldering process with a thermal sintering process that relies on direct metal-to-metal bonding through diffusion and metallurgical bonding. This substitution simplifies the manufacturing process by eliminating flux application, activation, and cleanup steps, thereby reducing process complexity while maintaining electrical coupling effectiveness
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 ensures strong, reliable attachment and electrical coupling of semiconductor chips to carriers with reduced mechanical stress and oxidation, while allowing for efficient heat dissipation and scalability in device fabrication.
Implementation Method 1
A method is disclosed that involves the application of a paste with electrically conductive particles, which are sintered onto a carrier
Implementation Method 2
using a controlled temperature process to prevent oxidation
Data Source
AI summary
An electronic device and fabrication of an electronic device. One embodiment provides applying a paste including electrically conductive particles to a surface of a semiconductor wafer. The semiconductor wafer is singulated with the electrically conductive particles for obtaining a plurality of semiconductor chips. At least one of the plurality of semiconductor chips is placed over a carrier with the electrically conductive particles facing the carrier. The electrically conductive particles are heated until the at least one semiconductor chip adheres to the carrier.