Contact Fill by Ionized Cluster Beam

Abstract

Ionized cluster beam (ICB) deposition of TiN barrier metal for ultra large scale integration (ULSI) applications has been developed. The bottom coverage of reactive-ICB was 54% and 24% for 4.0 and 6.7 aspect ratio contacts (2.0 µm in depth and 0.5 µm amd 0.3 µm in diameter). Therefore the ICB has high potential to fill sub-half-micron contact holes with high aspect ratios. The resistivity of Ti and TiN deposited by ICB and reactive-ICB is found to be 50 µQ cm and 180 µQ cm, respectively, at a substrate temperature of 300°C. The ICB can also provide low contact resistance and good adhesion by low energy ion bombardment during film growth. The beam simulation explains the bottom coverage of ICB as well as conventional sputtering. Using the larger number of atoms in a cluster, the bottom coverage becomes almost 100% due to the long mean free path of the deposited cluster in gas and its heavy mass.

Microstructuring characteristics of a chemically amplified photoresist synthesized for ultra-thick UV-LIGA applications

“…To accelerate the chemical amplified reaction, a PEB treatment is necessary because thermal energy will increase the mobility of photoacid proton and will also shorten the cycle time of the de-protection, structure rearrangement and new proton release. Therefore, one unit photacid proton can cause many cycles of such a catalytic reaction and the exposure dose can be also reduced [14][15][16]. Figure 3(d ) shows an SEM photograph of the gear mould of developed MMA/TBMA photoresist with a thickness of about 100 µm, indicating good enough selectivity between radiated and non-radiated zones during a long development process.…”

“…In this work, a novel positive-tone MMA/TBMA photoresist, which was prepared by a combination of copolymerization and chemical amplification (CA), was developed for use in the UV-LIGA process. The concept of CA was proposed by Ito and co-workers [14][15][16], its critical feature was that the acid-labile group attached to the polymer would react with the photogenerated acid in such a way that a new molecule of acid would be generated, thus beginning a catalytic cycle [17]. The use of chemically amplified reaction for resist photolithography offers the advantages of high sensitivity, high resolution and high contrast imaging; hence, several chemically amplified photoresists have also been expanded to be usable in deep-UV or electro-beam lithography [17].…”

Effects of photoacid generator decomposition on dissolution kinetics of poly(4-hydroxystyrene) in tetraalkylammonium hydroxide aqueous solutions

“…5) Among the requirements for resist materials, the suppression of stochastic effects, such as line width roughness (LWR) and stochastic defects (pinching and bridging), is the most difficult task to be accomplished. [6][7][8] Currently, chemically amplified resists 9,10) are used as standard materials in high-volume production lines of semiconductors. However, they may not be suitable for further miniaturization owing to acid diffusion.…”

Effect of Molecular Structure on Depth Profile of Acid Generator Distribution in Chemically Amplified Resist Films

“…Below 100 nm thickness, the effects of resist interfaces become increasingly important. Surface effects such as acid generator segregation, 2,3) T-top shape caused by an insoluble surface layer, 4,5) and film loss during development have been reported. In addition to these factors common to deep UV (DUV), EUV, and electron beam (EB) resists, a strong absorption has to be taken into account in EUV resists.…”