Backside Power Delivery with Grain-Aligned Conductors for Low Resistance
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Solution Overview
Problem
Conventional frontside power delivery in integrated circuits faces challenges as more components are built in multiple layers, leading to increased resistance and electromigration issues, which are exacerbated by the use of polycrystalline conductive materials with random grain orientations.
Innovation Solution
Implementing backside power delivery (BPD) using conductive materials with preferential grain alignment, which reduces the thickness of barrier material liners and minimizes electromigration, thereby reducing overall resistance and preserving performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If frontside power delivery is used in multi-layer integrated circuits, then power delivery is straightforward, but resistance increases and electromigration issues worsen
Solution Approach 1:
The patent inverts the conventional power delivery approach by delivering power from the backside of the substrate rather than the frontside. This inversion allows power to be delivered through a dedicated path that does not share resources with signal lines, thereby reducing electromigration and resistance issues while improving overall power delivery reliability
Solution Approach 2:
The patent transitions from two-dimensional frontside power delivery to three-dimensional backside power delivery. By utilizing the substrate's backside, the invention creates an additional dimensional space for power delivery, enabling separate power and signal paths that reduce interference and improve reliability
2Ease of manufacture
If polycrystalline conductive materials with random grain orientations are used, then manufacturing is easier, but electromigration increases
Solution Approach 1:
The patent changes the microstructural parameters of the conductive material by controlling grain orientation during deposition. By adjusting deposition conditions to create preferential grain alignment, the invention reduces electromigration while maintaining manufacturing feasibility through controlled parameter changes in the deposition process
Solution Approach 2:
The patent employs conductive materials with specific grain structure characteristics, creating a composite microstructure that combines the ease of polycrystalline deposition with the electromigration resistance of oriented grains. This is achieved through controlled deposition processes that produce materials with intermediate properties between fully random and fully single-crystal structures
3Reliability
If barrier material liner thickness is increased, then electromigration is reduced, but resistance increases
Solution Approach 1:
The patent applies local quality optimization by using conductive materials with preferential grain alignment specifically in regions where electromigration is a concern. This localized improvement in material structure provides enhanced electromigration resistance without requiring increased barrier material thickness, thereby maintaining low resistance
Data Source
Figure 1A~1C
Figure 2A
Figure 2B
AI summary
Disclosed herein are IC structures with backside power delivery (BPD) using conductive materials with preferential grain alignment. An example IC structure may include a device layer including a plurality of transistors, the device layer having a first side and a second side opposite the first side; one or more backend layers at the first side of the device layer, the one or more backend layers including backend interconnects coupled to one or more of the plurality of transistors; and a BPD arrangement that includes one or more backside layers at the second side of the device layer, wherein the one or more backside layers include an insulator material, an opening in the insulator material, the opening lined with a liner material, and a conductive material within the opening lined with the liner material, wherein the conductive material has a preferential grain alignment.