Copper Wiring Protective Film Structure for Stable Semiconductor Processing
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Solution Overview
Problem
The challenge in semiconductor device manufacturing is the difficulty in processing metals like copper, aluminum, gold, and silver, which are used in wiring, leading to impurity diffusion into semiconductor films, affecting electrical characteristics and reliability.
Innovation Solution
A semiconductor device design that incorporates protective films to prevent metal elements from diffusing into the semiconductor film, using a stacked-layer structure of first and second protective films to cover conductive films, reducing exposure to plasma and minimizing impurity diffusion.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If copper, aluminum, gold, silver, or molybdenum is used as wiring material, then electrical conductivity is improved, but impurity diffusion into semiconductor film occurs causing deterioration of electrical characteristics
Solution Approach 1:
A protective film is introduced as an intermediary layer between the conductive film containing copper, aluminum, gold, silver, or molybdenum and the semiconductor film. This protective film prevents direct contact and diffusion of metal impurities into the semiconductor film while allowing the conductive film to maintain its electrical function. The protective film acts as a barrier that mediates the interaction between the conductive material and semiconductor material.
Solution Approach 2:
The structure is segmented into distinct layers: a first protective film in contact with the semiconductor film, the conductive film containing the metal material, and a second protective film on the opposite side. This segmentation separates the conductive material from the semiconductor material, preventing impurity diffusion while maintaining electrical conductivity through the segmented layered structure.
2Reliability
If protective films are added to prevent impurity diffusion, then reliability is improved, but device complexity increases
Solution Approach 1:
The protective film serves multiple functions simultaneously: it acts as a barrier to prevent impurity diffusion from the conductive film to the semiconductor film, serves as an etching mask during fabrication processes, and provides structural support. This multi-functionality reduces the need for additional separate components, thereby limiting the increase in device complexity while achieving improved reliability.
Data Source
AI summary
The stability of steps of processing a wiring formed using copper or the like is increased. The concentration of impurities in a semiconductor film is reduced. Electrical characteristics of a semiconductor device are improved. A semiconductor device includes a semiconductor film, a pair of first protective films in contact with the semiconductor film, a pair of conductive films containing copper or the like in contact with the pair of first protective films, a pair of second protective films in contact with the pair of conductive films on the side opposite the pair of first protective films, a gate insulating film in contact with the semiconductor film, and a gate electrode overlapping with the semiconductor film with the gate insulating film therebetween. In a cross section, side surfaces of the pair of second protective films are located on the outer side of side surfaces of the pair of conductive films.