3D Stacked Substrate TSV Interface with Conductive Coating
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Solution Overview
Problem
Current semiconductor device manufacturing faces challenges in scaling down solder bumps for smaller contact pads and tighter pitches, leading to mechanically and thermally weaker solder joints, along with issues of copper oxidation affecting electrical contact and high costs due to complex processes.
Innovation Solution
A 3D substrate stacking-joint interface structure is formed by bonding a pretreated through substrate via (TSV) protrusion with a conductive protective coating and isolation liner to another substrate, eliminating the need for top-side μ-bump photo processes and reducing current leakage, while using solder plating to enhance bonding.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of moving object
If solder bump sizes are decreased to accommodate smaller contact pads and pitches, then device integration density is improved, but solder joint mechanical and thermal strength deteriorates
Solution Approach 1:
The patent changes the material parameter from conventional eutectic solder to low-melting-point glass, fundamentally altering the bonding mechanism. This glass material enables strong mechanical and thermal bonds at smaller bump sizes while maintaining joint integrity, resolving the contradiction between miniaturization and joint strength
Solution Approach 2:
The patent uses a composite structure combining copper protrusions with low-melting-point glass bonding material. This composite approach allows the copper to provide structural strength while the glass provides bonding and sealing, achieving both small size and high joint strength simultaneously
2Ease of manufacture
If conventional eutectic solder is used for bonding, then ease of manufacture is maintained, but wetting performance on copper surface deteriorates
Solution Approach 1:
The patent changes the bonding material from conventional eutectic solder to low-melting-point glass, which exhibits superior wetting characteristics on copper surfaces. This material parameter change improves wetting performance while the low melting point maintains manufacturing simplicity through easy reflow processing
3Reliability
If copper is exposed during solder process, then electrical conductivity is maintained, but copper oxidation increases
Solution Approach 1:
The patent introduces low-melting-point glass as an intermediary material that bonds to the copper protrusion. This glass layer acts as a protective barrier preventing copper oxidation while maintaining electrical conductivity through the glass-copper interface, eliminating the need for complex protective atmosphere controls
Solution Approach 2:
The patent applies a protective coating on the copper protrusion before the bonding process. This preliminary protection prevents oxidation during subsequent processing steps, ensuring the copper remains in a clean, conductive state for optimal electrical contact
4Reliability
If first-side isolation and metallization are included in the process, then device reliability is improved, but manufacturing complexity and cost increase
Solution Approach 1:
The patent extracts and eliminates the first-side isolation and metallization steps from the conventional manufacturing process. By using direct copper protrusions with low-melting-point glass bonding, the process removes unnecessary intermediate layers and steps, reducing complexity and cost while maintaining device reliability through the effective bonding interface
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 allows for a smaller package size, reduced costs, and improved reliability by eliminating first-side isolation and metallization, and protects copper from oxidation, enhancing electrical and structural bonds.
Implementation Method 1
A first protruding portion of the TSV has a conductive protective coating and a second protruding portion of the TSV has an isolation liner
Implementation Method 2
using solder plating to enhance bonding
Data Source
AI summary
A system, a structure and a method of manufacturing stacked semiconductor substrates is presented. A first substrate includes a first side and a second side. A through substrate via (TSV) protrudes from the first side of the first substrate. A first protruding portion of the TSV has a conductive protective coating and a second protruding portion of the TSV has an isolation liner. The system further includes a second substrate and a joint interface structure that bonds the second substrate to the first substrate at the conductive protective coating of the first protruding portion of the TSV.