Semiconductor Conductive Plug Dielectric Spacer TDDB
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Solution Overview
Problem
As semiconductor integrated circuit technology advances, the shrinking size of gate lines and increasing device density lead to deteriorated time-dependent dielectric breakdown (TDDB) performance of dielectric materials between conductive plugs, affecting electrical performance and reliability.
Innovation Solution
A two-step approach is used to form a dielectric spacer on the lower portion of a conductive structure, surrounding the upper portion, which increases the distance between conductive structures and enhances electrical performance and reliability by forming a semiconductor device with a semiconductor substrate, gate structures, source/drain region, dielectric layer, and conductive barrier layer.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If the spacing between gate lines is reduced to increase device density, then the device density increases, but the TDDB performance of dielectric material between conductive plugs deteriorates
Solution Approach 1:
The conductive plug formation process is segmented into two distinct steps: first forming a lower conductive plug portion, then forming an upper conductive plug portion. This segmentation allows for optimized dielectric spacer formation between the portions, improving TDDB performance while maintaining reduced gate line spacing for high device density.
Solution Approach 2:
The invention introduces a vertical dimension to the conductive plug structure by creating distinct lower and upper portions separated by a dielectric spacer. This vertical segmentation within the plug structure allows improved electrical isolation and TDDB performance without requiring increased horizontal spacing between gate lines, thus maintaining high device density.
2Reliability
If the spacing between gate lines is reduced to enhance integrated circuit integrity, then the circuit integrity improves, but the process window for forming conductive plugs becomes extremely small
Solution Approach 1:
The conductive plug formation is divided into two separate manufacturing steps with a dielectric spacer formation in between. This segmentation creates a larger effective process window by allowing independent optimization of each step, avoiding the extremely tight process constraints that would result from attempting to form a single conductive plug at reduced gate line spacing.
Solution Approach 2:
A dielectric spacer is introduced as an intermediary layer between the lower and upper conductive plug portions. This intermediary structure provides better process control and larger process window by enabling separate formation and optimization of each conductive portion, while maintaining the required circuit integrity at reduced gate line spacing.
3Ease of manufacture
If a single-step conductive plug formation is used, then the manufacturing process is simpler, but the TDDB performance and electrical reliability deteriorate
Solution Approach 1:
The manufacturing process is segmented into two conductive plug formation steps with dielectric spacer formation in between. While this increases process steps, it significantly improves TDDB performance and electrical reliability by enabling optimized isolation between conductive portions, which cannot be achieved with single-step formation.
Solution Approach 2:
A dielectric spacer is introduced as an intermediary structure between conductive plug portions. This intermediary layer provides superior electrical isolation and TDDB performance compared to single-step formation, justifying the increased manufacturing complexity through improved device reliability.
Data Source
AI summary
A manufacturing method of a semiconductor device includes the following steps. A semiconductor substrate with gate structures formed thereon is provided. A source/drain region is formed in the semiconductor substrate and formed between the gate structures. A dielectric layer is formed on the source/drain region and located between the gate structures. An opening penetrating the dielectric layer on the source/drain region is formed. A lower portion of a first conductive structure is formed in the opening. A dielectric spacer is formed on the lower portion and on an inner wall of the opening. An upper portion of the first conductive structure is formed in the opening and on the lower portion. The dielectric spacer surrounds the upper portion of the first conductive structure. The first conductive structure is formed by two steps for forming the dielectric spacer surrounding the upper portion and improving the electrical performance of the semiconductor device.