Chemical Mechanical Polishing of Al-Co Films for Replacement Metal Gate Applications

Lagudu, Uma Rames Krishna; Chockalingam, Ashwin; Babu, S. V.

doi:10.1149/2.012305jss

Cited by 23 publications

(34 citation statements)

References 24 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The model is compared with the experimental data 52,53 and good agreement is obtained. Unless otherwise indicated, the specific values of the following parameters are set to be V = 0.5m/s, E p = 3M Pa, υ = 0.2, k 1 = 4.87×10 −6 m/s, M = 27g/mol and ρ 0 = 2.7g/cm 3 for convenience in the following simulation and verification.…”

Section: Resultsmentioning

confidence: 81%

See 1 more Smart Citation

A Material Removal Rate Model for Aluminum Gate Chemical Mechanical Planarization

Chen

2015

ECS J. Solid State Sci. Technol.

View full text Add to dashboard Cite

In this work, a new aluminum gate chemical mechanical planarization (CMP) model for material removal rate (MRR) is proposed in high-k metal gate (HKMG) process. Using the basic principles of steady-state oxidation reaction and mechanical abrasion mechanism, the combinational interaction of chemical and mechanical coupled effects on MRR was systematically described by process parameters, pad properties and concentration of oxidizer, and then balanced to construct an overall polishing rate. Because of the great significance of the slurry pH on MRR in CMP process, the effects of surface forces, including the influences of van der Waals (vdW) and double-layer (DL) forces simultaneously acted between the wafer and the particles were investigated. Meanwhile, the influence of particle sizes, abrasive loadings and zeta potentials of the wafer and particles on MRR was also analyzed. It is found that the attractive vdW forces strengthen the MRR, while the DL forces, calculated to be repulsive, lower the MRR. The magnitude of surface forces increases with a smaller particle size compared with the pad-particle force. When zeta potentials of the wafer and particles are considered as a function of slurry pH, the experimental trends for the MRR with slurry pH, applied pressure and abrasive loading were predicted well by the present model. Therefore, the governing equation of aluminum removal reveals some insights into the HKMG CMP process and can be utilized for optimizing and controlling the polishing rate of aluminum gate structures and performing sensitivity analyses of operating parameters. With the steady shrinkage of the feature size and device geometry of modern integrated circuits (ICs), chemical mechanical planarization (CMP) has become the most important process choice for the surface planarization in the fabrication of advanced multilever ICs in microelectronic industry.1 A variety of materials and structures, including copper damascene metallization, oxides in shallow trench isolation (STI) and inter-level dielectrics (ILD), replacement metal gate for high-k metal gate (HKMG) structures and fin field effect transistor (FinFET) devices are polished with different slurries. [2][3][4] In CMP process, a rotating wafer with different types of design structures is pushed against a rotating polishing pad which is immersed in slurries containing chemicals and abrasive particles. Pattern structures on the wafer surface are first chemically passivated by slurry chemicals and then removed by effects of contact interactions of abrasive particles which are trapped between the pad and the wafer. The contact mechanism of the particles in the slurry provides the opportunity to remove the material from the wafer surface at an acceptable production rate. 5The material removal rate (MRR) which has been studied extensively from both a modeling and experimental standpoint depends sensitively on pattern geometry, process parameters, chemical reactions, pad properties and mechanical abrasion. If the CMP process is not properly controlled...

show abstract

Section: Resultsmentioning

confidence: 81%

“…In the present calculation, the concentration of oxidizer is 0.003 mol/L, the particle diameter is 35 nm and the slurry pH is 6 which is same as the experiment. 53 The Fig. 2 shows that the increase of the abrasive loading leads to the increase of the MRR.…”

Section: Resultsmentioning

confidence: 94%

A Material Removal Rate Model for Aluminum Gate Chemical Mechanical Planarization

Chen

2015

ECS J. Solid State Sci. Technol.

View full text Add to dashboard Cite

show abstract

“…It is found that KMnO 4 is a good oxidizer which can achieve oxidbillity preservation and be used to enable the formation of a protective MnO 2 film to reduce the corrosion potential gap and minimize galvanic corrosion. 8,9 According to the Pourbaix diagram of Al, 7 the oxide or hydroxide is not stable and can be dissolved into the slurry under the acidic environment and the rate constant k 32 :…”

Section: Modelingmentioning

confidence: 99%

An Aluminum Gate Chemical Mechanical Planarization Model for HKMG Process Incorporating Chemical and Mechanical Effects

Chen

2014

ECS J. Solid State Sci. Technol.

View full text Add to dashboard Cite

In this work, a new aluminum gate chemical mechanical planarization (CMP) model is proposed in high-k metal gate (HKMG) process for controlling and simulating the metal gate height variation. It systematically captures the effects of mechanical abrasion and concentrations of different types of chemical reagents on material removal rate and surface height evolution. Based on the fundamentals of steady-state oxidation reaction and etched removal in addition to mechanical abrasion, the combinational synergistic interaction is described by separate kinetic parameters such as process parameters, pad properties and slurry chemistry. It can be seen that the removal rate and the coupled effects of the chemical additives are determined from a closed-form equation, making use of the concepts of chemical mechanical equilibrium, chemical kinetics and contact mechanics. The model prediction results show good agreement with the collected experimental data. The metal gate dishing post-Al-CMP is found to increase with increasing the pattern density when the line space is fixed. The dishing value increases with increasing the pattern density up to a certain maximum and then it decreases for a fixed pitch. The present model can be adopted to analyze the influence of the design pattern structures, slurry properties, pad characteristics and polishing conditions on removal rate and wafer surface evolution. The governing equation of aluminum removal and dishing effect reveal some insights into the polishing process and can be used for assisting in HKMG test pattern design and performing the sensitivity analyzes of operating parameters on surface topography during Al-CMP.With the steady shrinkage of the feature size and device geometry of modern integrated circuits (ICs), chemical mechanical planarization (CMP) has emerged as one of the most important solution for surface local and global planarization. Aluminum metal CMP (Al-CMP) process was once a key solution to form the Al damascene interconnects in back-end-of-line (BEOL) application. 1,2 However, due to the low resistivity and better reliability performance of copper, the Cu damascene approach has eventually taken up the mainstream in BEOL interconnect structures.In recent years, the introduction of high-k metal gate (HKMG) structure has enabled the resumption of Moore's Law at the 45/32 nm nodes, when conventional Poly/SiON gate stacks run out of steam. HKMG technology which adopts a replacement metal gate (RMG) approach promises to enable conventional scaling of the transistor as well as reduced stand-by power. Intel had the first 45 nm HKMG processor in volume production in 2007 and most of the foundries introduce HKMG to fabricate their 32/22 nm devices and products. 3 Correspondingly, poly opening polish (POP) processing before dummy poly removed and Al-CMP implementation after work function metal deposited, have been developed to fabricate the HKMG products. 4,5 During the Al metal gate CMP process, the combinational effect of the polishing pad, abrasive particles and chemi...

show abstract

“…In the alkaline region in the presence of KMnO4 four cathodic reactions, oxygen reduction (reaction 6) and the three permanganate ion (MnO 4 -reduction reactions (reaction7, 8 and 9) consume the electrons generated from the anodic reactions (1)(2)(3)(4)(5). It is well known that during the permanganate ion reduction, (MnO 4 -gets reduced to MnO2 and adsorbs on the surface of the metal films [7][8][9]. The MnO2 can in turn be reduced to Mn2O3 and MnOOH (reactions 8,9).…”

Section: Ru/tin As Barriermentioning

confidence: 99%

“…It is well known that during the permanganate ion reduction, (MnO 4 -gets reduced to MnO2 and adsorbs on the surface of the metal films [7][8][9]. The MnO2 can in turn be reduced to Mn2O3 and MnOOH (reactions 8,9). However, especially, in the KMnO4 oxidizer system, similar corrosion potential values of the three films Cu, Ru and TiN indicates that the MnO2, Mn2O3 and MnOOH formed on all the three surfaces could fill the porous regions as well as form an adsorbed passive layer on the respective oxides and hydroxides.…”

Section: Ru/tin As Barriermentioning

confidence: 99%

Mitigation of corrosion challenges for barrier films at advanced nodes

Sagi

Babu

2016

2016 China Semiconductor Technology International Conference (CSTIC)

Self Cite

View full text Add to dashboard Cite

show abstract

Chemical Mechanical Polishing of Al-Co Films for Replacement Metal Gate Applications

Cited by 23 publications

References 24 publications

A Material Removal Rate Model for Aluminum Gate Chemical Mechanical Planarization

A Material Removal Rate Model for Aluminum Gate Chemical Mechanical Planarization

An Aluminum Gate Chemical Mechanical Planarization Model for HKMG Process Incorporating Chemical and Mechanical Effects

Mitigation of corrosion challenges for barrier films at advanced nodes

Contact Info

Product

Resources

About