Copper-Ceramic Bonded Structure for Thermal Cycle-Resistant Substrates
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Solution Overview
Problem
High-temperature semiconductor devices require insulating circuit substrates that can withstand severe thermal cycles without breaking, as existing technologies fail to adequately suppress ceramic substrate failure under such conditions.
Innovation Solution
A copper/ceramic bonded body is created with an active metal nitride layer on the ceramic side and a Mg solid solution layer between the nitride layer and the copper member, along with Cu-containing particles dispersed within the nitride layer, to enhance interfacial bonding and stress relaxation, using specific processing conditions to achieve reliable thermal cycle performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If conventional active metal brazing method using Ag-Cu-Ti-based brazing material is used to bond copper sheet to ceramic substrate, then bonding strength is improved, but ceramic substrate breaking occurs under severe thermal cycles
Solution Approach 1:
The invention changes the bonding parameters by using Cu-Mg-Ti-based brazing material with specific composition ratios (Mg: 3-15 wt%, Ti: 1-5 wt%) and controlling the bonding temperature (560-800°C) and atmosphere (nitrogen gas). This parameter optimization prevents ceramic substrate breaking while maintaining bonding strength, resolving the contradiction between bonding strength and thermal cycle reliability.
Solution Approach 2:
The invention uses a composite brazing material containing Cu, Mg, and Ti elements that work synergistically. The Cu-Mg-Ti-based brazing material forms a complex intermetallic compound structure at the bonding interface, providing both strong bonding and resistance to thermal cycling-induced breaking, thus resolving the contradiction between bonding strength and thermal reliability.
2Strength
If bonding temperature is increased to improve bonding strength, then bonding strength is improved, but Mg sublimation occurs and TiN formation is suppressed
Solution Approach 1:
The invention uses a nitrogen gas atmosphere during the bonding process to prevent Mg sublimation and control the chemical reactions. The nitrogen atmosphere provides an inert environment that suppresses Mg loss while allowing controlled formation of TiN and other intermetallic compounds, thus resolving the contradiction between bonding strength and Mg sublimation.
Solution Approach 2:
The invention optimizes the bonding temperature range (560-800°C) to achieve sufficient bonding strength while preventing excessive Mg sublimation. By carefully controlling the temperature parameter within this specific range and maintaining nitrogen atmosphere, the invention balances bonding strength improvement with prevention of Mg loss.
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 solution effectively suppresses ceramic substrate breaking during severe thermal cycles, ensuring high reliability and firm bonding between the copper and ceramic components, thereby improving the thermal cycle reliability of the insulating circuit substrate.
Implementation Method 1
a Mg solid solution layer in which Mg is solid-dissolved in a Cu matrix is formed between the active metal nitride layer and the copper member
Implementation Method 2
an active metal nitride layer containing nitrides of one or more active metals selected from Ti, Zr, Nb, and Hf is formed on a ceramic member side
Implementation Method 3
Cu-containing particles composed of either one or both of Cu particles and compound particles of Cu and the active metal are dispersed in an interior of the active metal nitride layer
Data Source
Figure 1~2
Figure 3
Figure 4
AI summary
This copper/ceramic bonded body (10) includes: a copper member (12, 13) made of copper or a copper alloy; and a ceramic member (11) made of nitrogen-containing ceramics, the copper member (12, 13) and the ceramic member (11) are bonded to each other, in which, between the copper member (12, 13) and the ceramic member (11), an active metal nitride layer (41) containing nitrides of one or more active metals selected from Ti, Zr, Nb, and Hf is formed on a ceramic member (11) side, and a Mg solid solution layer (45) in which Mg is solid-dissolved in a Cu matrix is formed between the active metal nitride layer (41) and the copper member (12, 13), and Cu-containing particles (42) composed of either one or both of Cu particles and compound particles of Cu and the active metal are dispersed in an interior of the active metal nitride layer (41).