Semiconductor Die Stacking Vertical Interconnects
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Solution Overview
Problem
Conventional semiconductor die stacking techniques result in long electrical pathways and limited heat sink mounting options, leading to slower performance and thermal management challenges.
Innovation Solution
A method and apparatus where a second semiconductor die is coupled to the opposite side of a first semiconductor die, with electrical connections formed between them, allowing for short electrical pathways and the availability of the bulk semiconductor side for heat sink mounting, using conductor structures and a metallization layer for efficient interconnects.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If bonding wires are used to establish electrical conductivity between stacked dice, then electrical connections are formed, but the electrical pathways become long and exhibit high inductance resulting in slower performance
Solution Approach 1:
The patent transitions from planar wire bonding to three-dimensional vertical interconnection through conductor bumps and through-silicon vias. This dimensional change allows electrical connections to be made directly through the substrate thickness rather than across the surface, dramatically shortening the electrical pathway and reducing inductance while maintaining connection reliability.
Solution Approach 2:
The patent introduces conductor bumps and through-silicon via structures as intermediary elements to establish direct electrical contact between stacked dice. These intermediaries replace the indirect wire bonding path with a streamlined conductive pathway that minimizes resistance and inductance, thereby improving signal speed while ensuring reliable electrical connection.
2Reliability
If conductor traces are formed on the bulk silicon side for electrical interconnects, then electrical connections are established, but the pathways represent high inductance and limit speed performance
Solution Approach 1:
The patent moves electrical interconnections from the two-dimensional surface plane to the three-dimensional vertical dimension by forming through-silicon vias and conductor bumps. This allows signals to travel directly through the substrate thickness rather than along surface traces, significantly reducing pathway length and inductance while maintaining connection reliability.
3Reliability
If multiple smaller dice are electrically interconnected using a metal layer and dielectric layer, then electrical connections are formed, but a very high degree of die alignment is required resulting in limited yields
Solution Approach 1:
The patent performs preliminary formation of conductor bumps and alignment features on the dice before the stacking process. This pre-preparation includes creating protruding conductor structures that self-align during bonding, eliminating the need for high-precision die alignment during assembly and thereby improving manufacturing yield while ensuring reliable electrical interconnections.
4Reliability
If dice are stacked with active circuitry sides facing each other, then electrical connections can be established, but the bulk semiconductor side is not available for heat sink mounting
Solution Approach 1:
The patent utilizes the vertical dimension by stacking dice with their bulk silicon sides facing each other, leaving the active circuitry sides exposed on the outer surfaces. This three-dimensional arrangement simultaneously enables electrical connections through the substrate thickness and provides access to both active sides for heat sink mounting, resolving the thermal management constraint.
Data Source
AI summary
Various stacked semiconductor devices and methods of making the same are provided. In one aspect, a method of manufacturing is provided that includes providing a first semiconductor die that has a first bulk semiconductor side and a first opposite side. A second semiconductor die is provided that has a second bulk semiconductor side and a second opposite side. The second opposite side of the second semiconductor die is coupled to the first opposite side of the first semiconductor die. Electrical connections are formed between the first semiconductor die and the second semiconductor die.