Self-Aligned Shallow and Deep Contacts for Equal Spacing
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Solution Overview
Problem
Conventional semiconductor device fabrication techniques face challenges in maintaining consistent spacing between shallow and deep electrical contacts, leading to potential electrical shorts due to misalignment issues when using separate masks for these contacts.
Innovation Solution
A self-aligned method is employed to form shallow and deep metal contacts using ring-shaped structures of a metallic layer, eliminating the need for separate masks and ensuring equal spacing between contacts, thereby preventing misalignment and shorts.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If separate masks are used for forming shallow and deep contacts, then the fabrication process can be simplified in terms of process steps, but manufacturing precision deteriorates leading to misalignment and inconsistent spacing between contacts
Solution Approach 1:
The patent employs a self-aligned fabrication process where the deep contact holes are formed first, then shallow contact holes are formed using the deep contact structures as alignment references. This self-service approach ensures that the shallow contacts are automatically positioned relative to the deep contacts, eliminating misalignment issues while maintaining consistent spacing without requiring complex separate mask alignment procedures
Solution Approach 2:
The patent performs preliminary formation of deep contact holes and their associated structures before forming the shallow contact holes. This preliminary action establishes fixed reference points that guide the subsequent shallow contact formation, ensuring precise spacing and alignment is achieved before the final contact pattern is completed
2Productivity
If critical dimensions are reduced for IC miniaturization, then device integration density is improved, but manufacturing precision deteriorates making it harder to maintain consistent contact spacing
Solution Approach 1:
By using the deep contact structures as self-aligned references for shallow contact formation, the process automatically maintains precise spacing even as critical dimensions are reduced. This self-service mechanism scales down with the device, ensuring consistent contact spacing is maintained throughout IC miniaturization and high-density integration
3Productivity
If contact spacing is reduced to increase device density, then productivity is improved, but reliability deteriorates due to increased risk of electrical shorts between contacts
Solution Approach 1:
The self-aligned process ensures that shallow contacts are precisely positioned relative to deep contacts, maintaining consistent spacing even when overall device density is increased. This precise positioning control prevents electrical shorts between adjacent contacts while still allowing high-density integration to be achieved
Data Source
AI summary
A semiconductor device is provided. The semiconductor device includes an interlayer dielectric layer; and a plurality of metal contacts formed in the interlayer dielectric layer. The plurality of metal contacts include a plurality of shallow metal contacts having a first depth, and a plurality of deep metal contacts having a second depth that is greater than the first depth, wherein a first one of the shallow metal contacts overlaps and directly contacts a first one of the deep metal contacts, and wherein the plurality of metal contacts have an equal spacing therebetween.