Embedded Isolation Dielectric Gate Stack for Short-Circuit Prevention
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Solution Overview
Problem
The continuous reduction in semiconductor device critical dimensions leads to smaller contact holes and closer proximity between gates and contact holes, increasing the likelihood of short-circuits during the dual-contact-hole process.
Innovation Solution
A gate stack structure is developed with an isolation dielectric layer embedded in the gate, where the sidewall spacer covers the isolation dielectric layer, and the layer on the active region is thicker than on the connection region, creating an isolation zone to prevent short-circuits, and the material of the isolation dielectric layer can differ from the barrier layer to minimize etching damage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the critical dimension is reduced continuously, then the device size and contact hole size are reduced, but the distance between gate and contact hole is reduced causing increased short-circuit risk
Solution Approach 1:
The patent introduces an isolation dielectric layer embedded within the gate structure, creating a vertical isolation barrier. This adds a dimensional element (vertical isolation) to prevent lateral short-circuits between the contact hole and gate, allowing continued scaling while maintaining reliability.
Solution Approach 2:
The isolation dielectric layer acts as an intermediary barrier between the conductive gate and the contact hole. By placing this dielectric material within the gate stack, it mediates the electrical interaction and prevents direct contact that would cause short-circuits.
2Reliability
If the isolation dielectric layer is made thicker on the active region, then the vertical distance to the contact hole is increased reducing short-circuit risk, but the gate structure becomes more complex
Solution Approach 1:
The isolation dielectric layer is implemented with different thicknesses in different regions: thicker on the active region where isolation is most critical, and thinner or absent on the connection region. This local differentiation provides targeted isolation effectiveness while minimizing overall structural complexity.
Data Source
AI summary
A gate stack structure comprises an isolation dielectric layer formed on and embedded into a gate. A sidewall spacer covers opposite side faces of the isolation dielectric layer, and the isolation dielectric layer located on an active region is thicker than the isolation dielectric layer located on a connection region. A method for manufacturing the gate stack structure comprises removing part of the gate in thickness, the thickness of the removed part of the gate on the active region is greater than the thickness of the removed part of the gate on the connection region so as to expose opposite inner walls of the sidewall spacer; forming an isolation dielectric layer on the gate to cover the exposed inner walls. There is also provided a semiconductor device and a method for manufacturing the same. The methods can reduce the possibility of short-circuit occurring between the gate and the second contact hole and can be compatible with the dual-contact-hole process.