Skip Via Structures with Protective Masking for Wiring Integrity
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Solution Overview
Problem
The manufacturing process of skip vias often results in surface damage to upper wiring structures due to differences in etch depths, leading to higher resistivity and decreased device performance.
Innovation Solution
A protective material, such as a sacrificial plug, is formed over the exposed surface of the upper wiring structure during the skip via etching process to prevent damage, and is subsequently removed after formation to allow for conventional metallization processes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If skip via etching process is performed to connect lower wiring structures, then area efficiency and capacitance reduction are improved, but surface damage occurs to upper wiring structures leading to higher resistivity
Solution Approach 1:
A protective material is introduced as an intermediary substance during the skip via etching process. This material is deposited over the upper wiring structure surface before etching, acting as a mediator that prevents direct contact between the etching chemistry and the copper wiring, thereby preventing surface damage while allowing the skip via to be formed through the dielectric to reach the lower wiring structure.
Solution Approach 2:
The protective material is applied in advance before the skip via etching process begins. This preliminary action ensures that the upper wiring structure surface is protected prior to exposure to the etching chemistry, preventing damage before it can occur. The protective layer is then removed after the etching is complete, leaving the wiring structure intact.
2Quantity of substance
If skip via etching process is performed to bypass upper wiring levels, then capacitance for lower wiring structure is minimized, but surface damage results at the interface between upper wiring structure and via interconnect structure
Solution Approach 1:
The protective material serves as an intermediary barrier between the etching process and the upper wiring structure surface. It allows the etching to proceed through the dielectric material to create the skip via while preventing the etching chemistry from attacking the copper surface, thus maintaining manufacturing precision and preventing surface damage.
Solution Approach 2:
The protective material temporarily introduces an additional processing step, but this apparent complexity converts the potential harm of etching-induced surface damage into a benefit by enabling the skip via process to proceed without compromising the upper wiring structure integrity.
Data Source
AI summary
The present disclosure relates to semiconductor structures and, more particularly, to skip via structures and methods of manufacture. The structure includes: a first wiring layer with one or more wiring structures; a second wiring layer with one or more wiring structures, located above the first wiring layer; a skip via with metallization, which passes through upper wiring levels including the second wiring layer and which makes contact with the one or more wiring structures of the first wiring layer; and a via structure which comprises a protective material and contacts at least one of the one or more wiring structures at the upper wiring level.