Copper Bonding Paste for Pressureless Low-Hydrogen Sintering
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Solution Overview
Problem
The challenge is to achieve sufficient bonding strength for semiconductor devices in a non-pressure condition without hydrogen or with low hydrogen concentration, as existing methods like sintered silver or copper layers require high pressure and are costly, and silver has high material costs.
Innovation Solution
A metal paste containing copper particles and a coordinating compound with electron back donation properties, such as nitrogen-containing aromatic heterocyclic compounds, is used, which allows for bonding in a non-pressure, low-hydrogen atmosphere, ensuring strong connections.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If sintered silver layer is used to achieve high thermal conductivity and connection reliability, then thermal conductivity is improved, but material cost increases and high pressurization is required
Solution Approach 1:
The patent substitutes expensive silver particles with cheaper copper particles as the metal powder in the paste. This replacement maintains the essential function of forming a sintered bonding layer while significantly reducing material cost, aligning with the principle of using cheaper materials to achieve the same functional outcome.
Solution Approach 2:
The patent introduces a sintering accelerator compound that enables sintering to proceed at lower pressures and temperatures. By changing the chemical parameters (adding the accelerator compound), the physical conditions required for sintering are modified, allowing the process to occur under milder conditions without compromising bonding strength.
2Reliability
If thermal compression bonding with high pressurization is applied to improve density of sintered silver layer, then connection reliability is improved, but damage to semiconductor element chip occurs and throughput decreases
Solution Approach 1:
The patent modifies the sintering process parameters by introducing a sintering accelerator compound. This chemical additive changes the sintering behavior to occur at lower pressures and temperatures, eliminating the need for high pressurization that causes chip damage and reduces throughput.
Solution Approach 2:
The sintering accelerator compound acts as an intermediary substance that facilitates the sintering process. It mediates between the copper particles and the sintering conditions, enabling particle bonding to occur under milder conditions without requiring extreme pressure that would damage the chip or reduce production speed.
3Strength
If sintered copper layer is formed by reducing and sintering copper oxide particles in hydrogen atmosphere, then bonding strength is improved, but equipment must be made explosion-proof when hydrogen concentration exceeds 10%
Solution Approach 1:
The patent replaces the hydrogen atmosphere with a sintering accelerator compound that enables reduction and sintering in a safer environment. The accelerator compound allows the process to proceed without requiring explosive hydrogen gas, thereby eliminating the need for explosion-proof equipment while maintaining bonding strength.
Solution Approach 2:
The patent uses a organic sintering accelerator compound as a substitute for hydrogen gas. This compound serves the same functional purpose of enabling reduction and sintering but without the safety hazards and equipment complexity associated with hydrogen, effectively replacing a dangerous substance with a safer alternative.
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 enables strong bonding of semiconductor devices without the need for high-pressure conditions, reducing material costs and maintaining connection reliability, even in low-hydrogen environments.
Implementation Method 1
a sintered silver layer formed by the sintering phenomenon of silver particles
Implementation Method 2
the sintering accelerator includes a coordinating compound having electron back donation properties
Data Source
AI summary
A metal paste for bonding contains metal particles, a dispersion medium, and a sintering accelerator, the metal particles contain copper particles, the sintering accelerator includes a coordinating compound having electron back donation properties, and the coordinating compound is at least one type selected from the group consisting of a nitrogen-containing aromatic heterocyclic compound, an acetylene derivative, an ethylene derivative, an organic arsenic compound, and a cyanide.