TiCl4 Barrier Process Engineering in Semiconductor Manufacturing
Titanium nitride (TiN) not only was utilized in the wear-resistant coatings industry but it was also adopted in barrier processes for semiconductor manufacturing. Barrier processes include the titanium (Ti) and TiN processes, which are commonly used as diffusion barriers in via/contact applications. However, engineers frequently struggle at the via/contact module in the beginning of every technology node. As devices shrink, barrier processes become more challenging to overcome the both the physical fill-in and electrical performance requirements of advanced small via/contact plugs. The aim of this paper is to investigate various chemical vapor deposition (CVD) TiCl4-based barrier processes to serve the application of advanced small via/contact plugs and the metal gate processes. The results demonstrate that the plasma-enhanced chemical vapor deposition (PECVD) TiCl4-based Ti process needs to select a feasible process temperature to avoid Si surface corrosion by high-temperature chloride flow. Conventional high step coverage (HSC) CVD TiCl4-based TiN processes give much better impurity performance than metal organic chemical vapor deposition (MOCVD) TiN. However, the higher chloride content in HSC film may degrade the long-term reliability of the device. Furthermore, it is evidenced that a sequential flow deposition (SFD) CVD TiCl4-based process with multiple cycles can give much less chloride content, resulting in faster erase speeds and lower erase levels than that of conventional HSC TiN.
Preparation and characterisation of acrylic resin for electro-deposited mono-coat coatings
ABSTRACT Acrylic resins are known for their multifarious characteristics. Diversified properties of acrylic resins have been utilised for the development of acrylic cationic electrodeposition multicolour mono-coat corrosion protective coatings by acrylic graft polymer of methyl acrylate, butyl acrylate, styrene, and methyl methacrylate in the presence of hydroxy propyl acrylate at 113–117°C in the presence of AIBN (Azo-bis iso-butyronitrile) as the initiator. The concept was to develop acrylic graft polymer wherein chemical bonds are protected against UV radiation 400 h or 18-month outdoor exposure. Developed acrylic resin has special characteristic e.g. excellent metal protection against corrosion 500 h salt spray test as per ASTM B117, excellent durability, economical primer, and finish coat in single application and meeting the International and National legislation. Resulting polymers were characterised by using FTIR spectroscopy, particle size analyser and other Morden instrumental techniques. Thus the obtained polymers have high solid content (72 ± 1%) and can be used in electrodeposition emulsion paint as a binder. The coatings are mono-coat prepared and their anticorrosion behaviour is discussed in this paper. The experimental results depict that the resin thus synthesised has high anticorrosive property, UV light stability, and excellent weather resistance.
The chromosomes of Chrysanthemum,
NEW varieties of the garden chrysanthemum arise primarily from seed. They are propagated vegetatively and many give rise to bud sports in sequence and in parallel to give whole families of varieties. The original sports would naturally be chimras and it is not surprising therefore that they often revert to the previous type. Whereas some varieties sport continually from the time of their origin, others remain stable for many years. Those considered in this account do, mostly, sport freely. Since varieties may remain stable for a considerable number of years and then suddenly sport it is probable that all varieties possess the ability to sport. The origin of bud sports is unpredictable. Some confusion in naming has arisen as the same or similar sports have occurred and been propagated in different places under different names. Consequently there are, for example, several forms similar to, but not identical with, the original Favourite Supreme raised by Messrs A. G. Vinten. It might well be that each individual variety would be better termed a sub-family to include all its minor variants. The different Chrysanthemum sports are described in scattered numbers of the R.H.S. Journal—more particularly, for the Favourite family, in Vol. 63, 1938, pp. 139-141. The object of this study is to discover the cause of sporting.