Semiconductor Contact Alignment via Gate Spacer Capping
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Solution Overview
Problem
As semiconductor devices undergo miniaturization, the gap between transistors and contacts decreases, leading to challenges in maintaining alignment during the Self Aligned Contact (SAC) process, which can result in electrical shorts to peripheral devices.
Innovation Solution
A method for fabricating semiconductor devices involves forming specific trench structures with gate spacers and electrodes, followed by capping patterns and interlayer insulating layers, allowing for precise control of contact formation to prevent shorts, including the use of passivation layers to protect gate spacers during etching.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the gap between contacts is decreased to achieve higher integration, then the productivity and integration degree are improved, but the alignment precision deteriorates leading to electrical shorts
Solution Approach 1:
The method forms gate spacers and capping patterns before forming the contact holes. The gate spacers are formed on the side walls of the gate electrodes, and the capping patterns are formed on top of the gate electrodes, creating a protective structure in advance that guides the subsequent contact hole formation process and prevents misalignment
Solution Approach 2:
The gate spacers and capping patterns serve as intermediary structures that mediate between the gate electrodes and the contact holes. These intermediary structures provide physical guidance and protection during the contact hole formation process, ensuring precise alignment even at reduced pitch
2Area of stationary object
If the contact pitch is reduced to increase device density, then the area is reduced, but the reliability deteriorates due to increased risk of electrical shorts
Solution Approach 1:
The protective structure consisting of gate spacers and capping patterns is formed before contact hole etching. This preliminary structure prevents electrical shorts by maintaining proper spacing and alignment throughout the contact formation process, ensuring reliability even when contacts are closely spaced
Solution Approach 2:
The gate spacers and capping patterns act as a protective cushion that prevents direct contact between the contact holes and gate electrodes. This protective structure absorbs potential alignment errors and prevents electrical shorts before they can occur
Data Source
AI summary
A method for fabricating a semiconductor device is disclosed. The method includes forming a first interlayer insulating layer including a first trench that is defined by a first gate spacer and a second trench that is defined by a second gate spacer on a substrate, forming a first gate electrode that fills a part of the first trench and a second gate electrode that fills a part of the second trench, forming a first capping pattern that fills the remainder of the first trench on the first gate electrode, forming a second capping pattern that fills the remainder of the second trench on the second gate electrode, forming a second interlayer insulating layer that covers the first gate spacer and the second gate spacer on the first interlayer insulating layer, forming a third interlayer insulating layer on the second interlayer insulating layer and forming a contact hole that penetrates the third interlayer insulating layer and the second interlayer insulating layer between the first gate electrode and the second gate electrode.