Semiconductor Metallization Without Adhesion Promoter
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Solution Overview
Problem
The production of semiconductor chips with diffusion solder connections is complex and costly, and the presence of an adhesion promoter layer leads to unreliable connections due to uncontrollable intermetallic phase growth, affecting the melting point and reproducibility of the soldering process.
Innovation Solution
A three-layer metallization structure without an adhesion promoter layer, comprising an aluminum layer, a diffusion barrier layer (Ti, Ni, or Cr), and a diffusion solder layer (Sn-based) applied by sputtering, which ensures a low-resistance contact, prevents diffusion reactions, and maintains mechanical and electrical stability without intermetallic phases, allowing for direct adhesion and reproducible soldering.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a four-layer metallization structure with adhesion promoter layer is used, then the adhesion between diffusion barrier layer and diffusion solder layer is improved, but the production complexity and cost increase
Solution Approach 1:
The invention extracts and removes the adhesion promoter layer from the traditional four-layer metallization structure. By eliminating this layer, the patent achieves reliable adhesion between the diffusion barrier layer and diffusion solder layer through direct contact, thereby reducing production complexity and cost while maintaining connection reliability.
Solution Approach 2:
The invention merges the functions of the adhesion promoter layer into the diffusion barrier layer by ensuring direct contact between the diffusion solder layer and diffusion barrier layer. This consolidation eliminates the need for a separate adhesion promoter layer, simplifying the metallization structure to three layers while maintaining effective adhesion.
2Reliability
If an adhesion promoter layer is used, then the adhesion between layers is improved, but the intermetallic phase growth becomes uncontrollable, affecting melting point and soldering reproducibility
Solution Approach 1:
The invention extracts and removes the adhesion promoter layer that causes uncontrollable intermetallic phase growth. By eliminating this layer, the patent prevents the formation of intermetallic phases at the interface between adhesion promoter and diffusion solder, thereby maintaining consistent melting points and reproducible soldering processes.
Solution Approach 2:
The invention converts the potential harm of having an adhesion promoter layer (which causes uncontrollable intermetallic phase growth) into a benefit by removing it. The direct contact between diffusion barrier layer and diffusion solder layer creates a controlled interface that prevents harmful intermetallic phase formation while maintaining reliable adhesion.
3Reliability
If a four-layer metallization structure is used, then the adhesion function is achieved, but the production time and cost increase
Solution Approach 1:
The invention extracts and removes the adhesion promoter layer from the metallization structure. This reduction from four layers to three layers decreases the number of deposition steps required during manufacturing, thereby reducing production time and cost while maintaining reliable connection through direct contact between the diffusion barrier layer and diffusion solder layer.
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 simplifies the production process, enhances the reliability of the semiconductor chip connection to a circuit carrier by eliminating the need for an adhesion promoter layer, ensuring consistent melting points and mechanical stability during thermal cycling, and reduces the complexity of the metallization structure.
Implementation Method 1
The aluminum layer has the function of specifying a low-resistance contact with the silicon of the semiconductor chip
Implementation Method 2
The diffusion barrier layer has the function of preventing a diffusion reaction between the aluminum layer and the diffusion solder
Implementation Method 3
All three layers are applied by sputtering in a process sequence
Data Source
AI summary
A semiconductor chip (1) is provided having an adhesion-promoting-layer-free three-layer metallization (2). The three-layer metallization (2) has an aluminum layer (4) applied directly on the semiconductor chip (1), a diffusion barrier layer (5) applied directly on the aluminum layer (4), and a solder layer (6) applied directly on the diffusion barrier layer (5). Ti, Ni, Pt or Cr is provided as the diffusion barrier layer (5) and a diffusion solder layer is provided as the solder layer (6). All three layers are applied by sputtering in a process sequence.