Diffusion Soldering for Semiconductor Chip Mounting
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current semiconductor chip packaging methods are costly and inefficient, particularly in forming reliable and high-yield connections between semiconductor chips and carriers, which hinders the cost-effective manufacturing of high-performance semiconductor devices.
Innovation Solution
The method involves depositing a solder material with specific metal compositions on both the semiconductor chip and carrier, followed by heating in a furnace to form intermetallic diffusion solder bonds, which provides strong mechanical and electrical connectivity without external pressure, using techniques like sputtering, electrochemical deposition, or printing, and applying these bonds to secure the chip to the carrier and contact clips.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If conventional packaging methods are used to mount semiconductor chips on carriers, then the manufacturing process is well-established and reliable, but the manufacturing cost is high and efficiency is low
Solution Approach 1:
The patent replaces conventional mechanical bonding methods (such as wire bonding and epoxy molding) with a diffusion-based bonding process. By depositing metal layers (e.g., copper, aluminum) on the chip and carrier surfaces and then heating them to enable atomic diffusion, the method creates strong metallurgical bonds without requiring complex mechanical assembly equipment, thereby reducing manufacturing cost and improving efficiency
Solution Approach 2:
The patent utilizes temperature as a critical parameter to enable diffusion bonding. By heating the deposited metal layers to specific temperatures (typically 200-400°C depending on the metal system), the process activates atomic diffusion between the chip and carrier surfaces, creating strong bonds. This parameter change transforms a low-cost deposition process into an effective bonding method, replacing expensive conventional packaging
2Reliability
If strong mechanical bonds are formed between semiconductor chips and carriers, then connection reliability is high, but the manufacturing process becomes complex and costly
Solution Approach 1:
The patent introduces deposited metal layers as an intermediary between the semiconductor chip and the carrier. These metal layers (such as copper, aluminum, or their alloys) serve as diffusion mediators that facilitate bonding between the chip substrate and carrier. The intermediary layers enable reliable metallurgical bonds while keeping the process simple, as they can be deposited using standard thin-film deposition techniques followed by a straightforward thermal diffusion step
Solution Approach 2:
The patent employs composite material systems consisting of multiple metal layers (e.g., copper-chromium, aluminum-silicon) to achieve both strong bonding and process simplicity. These composite material systems are designed to form intermetallic compounds during diffusion that provide strong mechanical and electrical bonds. The use of well-established metal deposition and diffusion couples simplifies the process while ensuring high connection reliability
3Strength
If conventional bonding methods are used, then the process is simple, but the connection strength and electrical conductivity are insufficient
Solution Approach 1:
The patent exploits phase transitions in metal materials during the diffusion process. By heating the deposited metal layers to temperatures where solid-state diffusion is activated, atoms migrate across the interface between chip and carrier, forming strong intermetallic bonds. The phase transition from simple physical deposition to thermally-activated diffusion creates strong bonds while maintaining process simplicity, as the same thermal processing equipment can be used
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 results in high-strength, high-conductivity intermetallic diffusion solder bonds that are thermally stable and cost-effective, enabling efficient and reliable mounting of semiconductor chips on carriers, thereby reducing manufacturing costs and improving yield.
Implementation Method 1
heating in a furnace to form intermetallic diffusion solder bonds
Implementation Method 2
depositing a solder material with specific metal compositions on both the semiconductor chip and carrier, followed by heating in a furnace
Implementation Method 3
depositing a solder material with specific metal compositions on both the semiconductor chip and carrier, followed by heating in a furnace, using techniques like sputtering, electrochemical deposition, or printing
Data Source
AI summary
A method includes providing a semiconductor chip having a first main surface and a second main surface. A semiconductor chip is placed on a carrier with the first main surface of the semiconductor chip facing the carrier. A first layer of solder material is provided between the first main surface and the carrier. A contact clip including a first contact area is placed on the semiconductor chip with the first contact area facing the second main surface of the semiconductor chip. A second layer of solder material is provided between the first contact area and the second main surface. Thereafter, heat is applied to the first and second layers of solder material to form diffusion solder bonds between the carrier, the semiconductor chip and the contact clip.