Semiconductor Bonding Passivation Layer for Low-Temperature Oxidation Control
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Solution Overview
Problem
In the semiconductor industry, high-temperature bonding processes can lead to failure and oxidation issues due to the sensitivity of metal bonding surfaces, which hinders the formation of strong and conductive bonds, especially as transistor dimensions shrink and heterogeneous integration increases.
Innovation Solution
A passivation layer with specific metal compositions (Au, Ag, Pt, Ru, Al, Cu, Pd) and a polycrystalline structure is applied to prevent premature oxidation, allowing metal atoms to diffuse effectively at low temperatures, forming a strong and conductive bonding structure.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If high-temperature bonding process is used, then bonding strength can be improved, but oxidation of metal bonding surfaces occurs and reliability deteriorates
Solution Approach 1:
The patent applies this principle by creating a controlled low-oxygen environment during the bonding process. The passivation layer is formed with specific metal compositions (Au, Ag, Pt, Ru, Al, Cu, Pd) that provide oxidation resistance, allowing the bonding to proceed in an effectively inert atmosphere that prevents metal surface oxidation while enabling strong bond formation.
Solution Approach 2:
The patent applies this principle by forming the passivation layer on the bonding surfaces before the actual bonding process occurs. This preliminary protective layer prevents oxidation of the metal surfaces prior to bonding, ensuring that the surfaces remain reactive and capable of forming strong bonds when brought into contact, thus resolving the contradiction between needing high temperature for strength and avoiding oxidation for reliability.
2Strength
If high-temperature bonding process is used, then bonding strength can be improved, but metal bonding surfaces oxidize and conductivity deteriorates
Solution Approach 1:
The passivation layer creates a protective environment that prevents oxidation of the metal bonding surfaces. By selecting metals with high oxidation resistance (such as Au, Pt, Ru) or controlling the layer composition to minimize oxygen interaction, the bonding process can achieve high temperature conditions for strong bonding without forming oxide layers that would increase contact resistance and degrade conductivity.
Solution Approach 2:
The patent applies this principle by using composite material compositions for the passivation layer, combining multiple metals (Au, Ag, Pt, Ru, Al, Cu, Pd) in specific ratios. This composite structure provides both the oxidation resistance needed to prevent surface degradation and the thermal conductivity necessary to maintain electrical performance, thus enabling high bonding strength without compromising conductivity.
3Adaptability or versatility
If multiple and high-temperature bonding processes are used, then heterogeneous integration can be achieved, but previous bonding fails due to excessive temperature
Solution Approach 1:
The passivation layer provides a protective inert environment that allows subsequent high-temperature bonding processes to proceed without oxidizing previously bonded interfaces. This enables multiple bonding steps in heterogeneous integration workflows, as each bonding operation can be performed at optimal temperature without compromising earlier bonds through thermal oxidation or contamination.
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 enables the formation of semiconductor bonding structures with high bonding strength and conductivity at temperatures below 200°C, preventing oxidation and ensuring reliable connections.
Implementation Method 1
the passivation layer can cover the surface of the bonding substrate to prevent oxidation before bonding process
Implementation Method 2
ensure the metal atoms of the bonding substrate to diffuse in a sufficient amount during the bonding process
Data Source
AI summary
Provided are a passivation layer for forming a semiconductor bonding structure, a sputtering target making the same, a semiconductor bonding structure and a semiconductor bonding process. The passivation layer is formed on a bonding substrate by sputtering the sputtering target; the passivation layer and the sputtering target comprise a first metal, a second metal or a combination thereof. The bonding substrate comprises a third metal. Based on a total atom number of the surface of the passivation layer, O content of the surface of the passivation layer is less than 30 at %; the third metal content of the surface of the passivation layer is less than or equal to 10 at %. The passivation layer has a polycrystalline structure. The semiconductor bonding structure sequentially comprises a first bonding substrate, a bonding layer and a second bonding substrate: the bonding layer is mainly formed by the passivation layer and the third metal.