Gate Contact Above Active Region for Semiconductor Packing Density
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Solution Overview
Problem
In integrated circuits, the positioning of gate contacts above the active region is limited, leading to space inefficiency due to the need to avoid electrical shorts, which hampers the packing density of transistor devices.
Innovation Solution
Methods are developed to form conductive gate contact structures completely above the active region of semiconductor devices, using techniques such as etching and metal deposition, with internal spacers to prevent contact with source/drain metallization structures, allowing for the formation of conductive gate and source/drain contacts in a sequence that optimizes space usage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If gate contacts are positioned above the active region, then packing density is improved, but risk of electrical shorts increases
Solution Approach 1:
The patent introduces an internal spacer as an intermediary structure positioned between the gate contact and the source/drain metallization structures. This spacer acts as a physical mediator that prevents direct contact and potential electrical shorts while allowing the gate contact to be positioned above the active region, thus resolving the contradiction between improved packing density and maintained electrical integrity.
Solution Approach 2:
The patent segments the contact formation process into distinct stages: first forming the gate contact structure, then subsequently forming the source/drain contact structures. This temporal segmentation allows each contact type to be independently positioned and isolated, enabling the gate contact to be placed above the active region without compromising electrical integrity through improper contact with source/drain structures.
2Area of stationary object
If gate contacts are positioned above the active region, then space utilization is improved, but manufacturing complexity increases
Solution Approach 1:
The patent applies preliminary action by forming the internal spacer structure in advance, before forming the source/drain contact structures. This pre-positioned spacer serves as a guide and protective element during subsequent manufacturing steps, simplifying the overall process despite the non-traditional gate contact positioning. The preliminary placement of the spacer reduces the complexity of maintaining proper spacing and preventing shorts during later stages.
3Reliability
If internal spacers are used to prevent contact, then electrical integrity is maintained, but device structure becomes more complex
Solution Approach 1:
The internal spacer serves multiple functions simultaneously: it acts as a physical barrier to prevent electrical shorts between gate and source/drain structures, provides structural support during subsequent processing steps, and defines the spatial relationship between different contact structures. This multi-functionality justifies the additional structural element by providing multiple benefits beyond merely preventing shorts.
Data Source
AI summary
One illustrative method disclosed includes, among other things, completely forming a first conductive structure comprising one of a conductive gate contact structure (CB) or a conductive source/drain contact structure (CA), wherein the entire conductive gate contact structure (CB) is positioned vertically above a portion of an active region of a transistor device, and, after completely forming the first conductive structure, completely forming a second conductive structure comprising the other of the conductive gate contact structure (CB) or the conductive source/drain contact structure (CA).