Gate Sidewall Protective Structure for Tungsten Residue Isolation
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
As semiconductor devices become smaller, tungsten residue around stitch or peripheral circuit regions forms leakage paths between source and drain contacts, decreasing yield due to integration challenges in semiconductor process technology.
Innovation Solution
A semiconductor device and method involving a substrate with first and second gate structures, where a protective structure with different dielectric materials is formed to cover the sidewall of one of the first gate structures adjacent to the second region, preventing tungsten residue and leakage paths by using a sacrificial material, stop layer, and interlayer dielectric layer to create a protective layer during the etching process.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If line width is reduced to make devices light, thin, and compact, then integration increases and products become smaller, but tungsten residue forms around stitch and peripheral circuit regions creating leakage paths
Solution Approach 1:
A protective structure is formed in advance around the first gate structure adjacent to the second region before the etching process. This protective structure includes a lower portion and an upper portion with different dielectric materials, creating a barrier that prevents tungsten residue from forming leakage paths between source and drain contacts during subsequent processing steps.
Solution Approach 2:
The protective structure is selectively formed only around specific gate structures adjacent to stitch or peripheral circuit regions where tungsten residue problems occur. The lower and upper portions use different dielectric materials tailored to local requirements, providing targeted protection without affecting other areas of the device.
2Ease of manufacture
If conventional etching process is used without protective structure, then manufacturing is simpler, but stop layer is lost during etching back process causing tungsten residue
Solution Approach 1:
The protective structure is formed preliminarily before the etching and etching back processes. This pre-formed structure acts as a barrier that prevents stop layer loss during etching back, ensuring precise contact formation without requiring complex process modifications.
Solution Approach 2:
The protective structure serves as an intermediary barrier between the etching process and the stop layer. It mediates the interaction by absorbing or preventing the etching attack from reaching the stop layer, thus protecting the stop layer from being lost during the etching back process.
Data Source
AI summary
Provided is a semiconductor device including a substrate, multiple first gate structures, and a protective structure. The substrate includes a first region and a second region. The first gate structures are disposed on the substrate in the first region. The protective structure conformally covers a sidewall of one of the first gate structures adjacent to the second region. The protective structure includes a lower portion and an upper portion disposed on the lower portion. The lower portion and the upper portion have different dielectric materials. A method of forming a semiconductor device is also provided.