Effect of Potassium Tartrate on Removal Rate Selectivity of Co/TiN/TEOS for Cobalt “Buff Step” Chemical Mechanical Planarization

Self Cite

In this study, the passivation mechanism of three azole inhibitors with different functional groups, benzotriazole (BTA), 5-methylbenzotriazole (TTA), 1-H carboxyl benzotriazole (CBT), on cobalt in H 2 O 2 based slurry were investigated. Results showed that cobalt (Co) has the highest removal rate (RR) and static etching rate (SER) in the solution without inhibitors, and RR and SER of Co decreased when three inhibitors were added to the reference solution respectively. However, compared with BTA and TTA, CBT showed the strongest passivation effect. Through the single frequency EIS experiments and X-ray photoelectron spectroscopy (XPS) measurements analysis, all three azole inhibitors can react with Co 2+ to form insoluble networked nanoparticles on the Co surface, but CBT had the thickest passivation film, which was inferred that the carboxyl group on the CBT can not only increase the coverage area on the Co surface like the methyl group, but also the oxygen on the carboxyl group can chemically adsorb on the Co surface like the N 17 on the imidazole ring. Moreover, TTA showed better passivation effect than BTA due to the existence of the methyl on TTA, which can increase the coverage area on Co surface and prevent the polishing slurry from contacting Co surface.

Section: Resultsmentioning

confidence: 99%

Effect of Benzotriazole and 5-Methyl/1-H Carboxyl Benzotriazole on Chemical Mechanical Polishing of Cobalt in H₂O₂ Based Slurry

Lei

Wang

et al. 2021

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“…SiO 2 film was in contact with water, siloxane bonds (Si-O-Si) at the surface of SiO 2 film were converted to silanol groups (Si-OH) through a hydrolysis reaction (i.e. hydroxylation) via the reaction 1, 4,5,[19][20][21][22] and the schematic diagram is shown in Figs. 2a, 2b.…”

Section: Resultsmentioning

confidence: 99%

Role of Slurry Additives on Chemical Mechanical Planarization of Silicon Dioxide Film in Colloidal Silica Based Slurry

Wang

Zhou

et al. 2021

Self Cite

Chemical mechanical planarization (CMP) is a critical process for smoothing and polishing the surfaces of various material layers in semiconductor device fabrication. The applications of silicon dioxide films are shallow trench isolation, an inter-layer dielectric, and emerging technologies such as CMOS Image Sensor. In this study, the effect of various chemical additives on the removal rate of silicon dioxide film using colloidal silica abrasive during CMP was investigated. The polishing results show that the removal rate of silicon dioxide film first increased and then decreased with an increasing concentration of K+, pH, and abrasive size. The removal rate of silicon dioxide film increased linearly as the abrasive concentration increased. The influence mechanisms of various additives on the removal rate of silicon dioxide film were investigated by constructing simple models and scanning electron microscopy. Further, the stable performance of the slurry was achieved due to the COO- chains generated by poly(acrylamide) hydrolysis weaken the attraction between abrasives. High-quality wafer surfaces with low surface roughness were also thus achieved. The desirable and simple ingredient slurry investigated in this study can effectively enhance the planarization performance, for example, material removal rates and wafer surface roughness.

“…According to the principle of mutual attraction of dissimilar charges, the electrostatic repulsion between the abrasive and TEOS was weakened by K + , which raised the mechanical friction, then the RR of TEOS was increased. 23,24 With the addition of 0.05 wt% HPAA, the RR of Cu/Co/TEOS were 163 Å min −1 , 350 Å min −1 , and 374 Å min −1 , respectively. Therefore, the RR selectivity of Co to Cu and TEOS to Cu were V Co /V Cu ≈ 2.15, V TEOS /V Cu ≈ 2.30, respectively, which could effectively remove the material and reduce the depth of dishing and erosion.…”

Section: Resultsmentioning

confidence: 99%

“…The reactions could be written as follows:21 It was well known that weak ionization of Co(OH) 2 could produce Co 2+ , as shown in reaction 9 22. Co 2+ reacted with H 2 O 2 to generate Co 3+ and free hydroxyl groups 23. HPAA reacted with Co 2+ /Co 3+ to form easily soluble complexes to improve the RR of Co (Reactions 10-12).…”

mentioning

confidence: 99%

The Effect of 2-hydroxyphosphonoacetic Acid on the Removal Rate Selectivity of Cu/Co/TEOS in H₂O₂Based Alkaline Slurries

Liu

Zhu

et al. 2021

As the technology node shrinks to 14 nm, Co has been widely used as a liner in semiconductor devices. However, the dishing and erosion produced after fine polishing seriously affect the RC delay of the device, so achieving a reasonable Cu/Co/TEOS removal rate (RR) selectivity is the key to correct the dishing and erosion. In this paper, the effect of 2-hydroxyphosphonoacetic Acid (HPAA) as a complexing agent on Cu/Co/TEOS RR selectivity in H2O2 based alkaline slurries was well investigated. In addition, the complexation mechanism between Co and HPAA was analyzed through electrochemical experiments, UV/vis, XPS tests, etc. The results showed that the RRs of Cu/Co/TEOS in the optimized slurry containing 5 wt% SiO2, 0.15 wt% H2O2, 0.05 wt% HPAA, 500 ppm TT-LYK at pH = 10 are ∼ 163 Å min−1, ∼ 350 Å min−1, ∼ 374 Å min−1, respectively. The RR selectivity of Co to Cu (VCo/VCu) and TEOS to Cu (VTEOS/VCu) were ∼ 2.15 and ∼ 2.3. At this time, the surface quality of the polished wafer was good, the dishing was corrected by ∼ 910 Å, and the erosion was corrected by ∼ 1117 Å.