Semiconductor Bonding Structure for Low-Temperature 3D IC Joining
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Copper-copper bonding in three-dimensional integrated circuits is prone to failure and requires high temperatures, limiting material and process selection and increasing the difficulty of achieving surface flatness.
Innovation Solution
A semiconductor structure with a first bonding structure comprising a first metal layer and a second metal layer with a lower melting point, featuring a groove and a conductive via that coincides with the groove projection, allowing bonding at lower temperatures and promoting intermetallic compound formation through thermal expansion.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If copper-copper bonding is used in three-dimensional integrated circuits, then bonding between wafers can be achieved, but the bonding is prone to failure and requires high temperatures
Solution Approach 1:
The patent uses a composite bonding structure consisting of a first metal layer (Cu) and a second metal layer (low melting point metal) in the first bonding structure, and a third metal layer (Cu) in the second bonding structure. This composite material approach allows bonding at lower temperatures while improving bonding reliability by combining the advantages of different materials.
Solution Approach 2:
The patent changes the material composition and melting point parameters of the bonding structures. By introducing a second metal layer with lower melting point than copper, the bonding temperature parameter is reduced, and the bonding reliability is improved through the phase transition characteristics of the low melting point metal.
2Ease of manufacture
If high temperature bonding is used, then copper-copper bonding can be achieved, but material and process selection is limited and manufacturing difficulty increases
Solution Approach 1:
By changing the material parameters (introducing low melting point metals) and temperature parameters, the patent enables bonding at lower temperatures, which expands material and process selection options and reduces manufacturing difficulty.
3Manufacturing precision
If copper-copper bonding is used, then bonding can be achieved, but surface flatness requirements become more difficult to achieve
Solution Approach 1:
The patent utilizes the phase transition (melting and solidification) of the low melting point metal in the second metal layer during bonding. This phase transition allows the material to flow and fill gaps, automatically compensating for surface flatness variations and reducing the stringency of surface flatness requirements.
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
Enhances bonding reliability by reducing the need for high-temperature bonding and improving surface flatness requirements, ensuring successful fusion even with small gaps.
Implementation Method 1
promoting intermetallic compound formation through thermal expansion
Implementation Method 2
a second metal layer with a melting point lower than a melting point of the first metal layer
Data Source
Figure 1~3
Figure 4~6
Figure 7~8b
AI summary
A semiconductor structure is provided. The semiconductor structure includes a first substrate, and a first bonding structure and a first conductive via which are formed in the first substrate. The first bonding structure includes a first metal layer and a second metal layer with a melting point lower than a melting point of the first metal layer. The first metal layer includes a first surface and a second surface arranged opposite to each other. The first surface of the first metal layer is provided with a first groove, and the second metal layer is arranged in the first groove. The first conductive via is in contact with the second surface of the first metal layer. A projection of the first conductive via coincides with a projection of the first groove in a direction perpendicular to the first surface of the first metal layer.