Semiconductor Device Contact Insulation via Dielectric Pillar
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Solution Overview
Problem
In three-dimensional NAND flash memory devices, there is a challenge in preventing electrical connections between contacts and conductive layers of lower layers, leading to potential short circuits and reduced integration due to the staircase structure of conductive layers, where contacts may penetrate through and connect with lower layer conductive layers.
Innovation Solution
The semiconductor device employs a dielectric support pillar with a larger diameter than the contact, positioned to prevent contact with the lower layer conductive layer, and a metal film with a larger thickness than the conductive layer to increase the process margin and avoid short circuits, while also using a spacer film to enhance insulation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If contacts are formed to connect upper layer conductive layers in the staircase structure, then electrical connection between layers is achieved, but contacts may penetrate through and create unwanted electrical connection with lower layer conductive layers
Solution Approach 1:
A dielectric film is introduced as an intermediary layer between the contact and the lower layer conductive layer. This dielectric film acts as a mediator that allows the contact to pass through while preventing direct electrical connection with the lower layer conductive layer, thus resolving the unwanted electrical connection issue while maintaining the necessary electrical connection function
Solution Approach 2:
The conductive layer is designed with locally varying thickness, being thicker in regions where contacts are formed and thinner in other regions. This local quality variation ensures that the contact can reliably connect to the conductive layer while the thicker portion provides sufficient material to prevent penetration through to lower layers, eliminating unwanted electrical connections
2Ease of manufacture
If the staircase structure is used to facilitate contact connection, then ease of manufacture is improved, but the terrace area increases reducing integration density
Solution Approach 1:
The thickness parameter of the conductive layer is dynamically adjusted based on the functional requirements of different regions. By changing the thickness parameter locally - thicker where contacts connect and thinner elsewhere - the design achieves both easy contact connection and reduced overall terrace area, thereby improving integration density while maintaining manufacturing ease
Data Source
AI summary
A semiconductor device according to an embodiment includes a first contact electrically connected to a first conductive layer with a diameter size smaller than a diameter size of a first support pillar at a region position on an inner side in a radial direction of the first support pillar in a first region and extending to the opposite side of the substrate with respect to the first conductive layer; and a second contact electrically connected to a second conductive layer with a diameter size smaller than a diameter size of a second support pillar at a position of penetrating through the first conductive layer at a region position on an inner side in a radial direction of the second support pillar in the first region and extending to the opposite side of the substrate with respect to the second conductive layer.