Semiconductor Gate Pads with Variable Thickness for Contact Reliability
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Solution Overview
Problem
Semiconductor devices with stack structures face challenges in maintaining electrical and mechanical reliability due to the need for increased integration and capacity, which can lead to issues such as the punching phenomenon during contact hole formation.
Innovation Solution
The semiconductor device incorporates R-type and P-type pads with varying thicknesses, where the R-type pad is thicker and connected to the gate electrodes, and the P-type pad is thinner and connected to the dummy word line, preventing the punching phenomenon by providing sufficient process margins and ensuring reliable contact formation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the thickness of gate pads is increased to prevent the punching phenomenon, then the reliability of contact formation is improved, but the manufacturing complexity and process difficulty increase
Solution Approach 1:
The patent applies different thicknesses to different pad types (R-type pads with greater thickness, P-type pads with lesser thickness) based on their specific functional requirements and vulnerability to punching phenomenon, rather than uniformly increasing all pad thicknesses. This localized differentiation resolves the contradiction by providing enhanced reliability only where needed while maintaining manufacturing simplicity.
Solution Approach 2:
The gate pad structure is segmented into multiple types (R-type and P-type) with different thickness characteristics. This segmentation allows each pad type to be optimized independently for its specific function, preventing the punching phenomenon in critical areas without unnecessarily complicating the entire pad structure.
2Quantity of substance
If more insulating layers and electrode layers are vertically stacked to increase device capacity, then the integration degree is improved, but the electrical and mechanical reliability deteriorates
Solution Approach 1:
The patent introduces dummy word lines with specific thickness characteristics at strategic locations within the stacked structure. These dummy elements provide localized mechanical support and electrical stabilization without requiring a complete redesign of the entire stack, thus maintaining high integration while improving reliability at critical points.
Solution Approach 2:
Dummy word lines are incorporated into the stack structure during the manufacturing process before final device operation. These preliminary structural elements prevent potential reliability issues from developing, providing mechanical support and electrical stability that preemptively address the challenges of high-density stacking.
3Reliability
If R-type pads with greater thickness are used for all gate electrodes, then the punching phenomenon is prevented, but the manufacturing process efficiency decreases
Solution Approach 1:
The patent applies greater thickness only to R-type pads that are more susceptible to the punching phenomenon, while P-type pads maintain lesser thickness. This selective approach prevents the punching phenomenon where needed without unnecessarily increasing manufacturing complexity and process time for all pads, thus resolving the contradiction between reliability and productivity.
Data Source
AI summary
A semiconductor device includes lower gate electrodes placed on a substrate and spaced apart from one another; upper gate electrodes placed over the lower gate electrodes and spaced apart from one another; an R-type pad extending from one end of at least one electrode among the lower gate electrodes or the upper gate electrodes and having a greater thickness than the lower gate electrode or upper gate electrode connected to the R-type pad; and a P-type pad extending from one end of at least one electrode to which the R-type pad is not connected among the lower gate electrodes or the upper gate electrodes and having a different thickness than the R-type pad, wherein the P-type pad includes a first pad connected to an uppermost lower gate electrode among the lower gate electrodes.