• Tribology and Lubricants
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• 제31권6호
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• pp.239-244
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• 2015

Chemical mechanical polishing (CMP) is one of the most important processes for enabling sub-14 nm semiconductor manufacturing. Moreover, post-CMP defect control is a key process parameter for the purpose of yield enhancement and device reliability. Due to the complexity of device with sub-14 nm node structure, CMP-induced defects need to be fixed in the CMP in-situ cleaning module instead of during post ex-situ wet cleaning. Therefore, post-CMP in-situ cleaning optimization and cleaning efficiency improvement play a pivotal role in post-CMP defect control. CMP in-situ cleaning module normally consists of megasonic and brush scrubber processes. And there has been an increasing effort for the optimization of cleaning chemistry and brush scrubber cleaning in the CMP cleaning module. Although there have been many studies conducted on improving particle removal efficiency by brush cleaning, these studies do not consider the effects of brush contamination. Depending on the process condition and brush condition, brush cross contamination effects significantly influence post-CMP cleaning defects. This study investigates brush cross contamination effects in the CMP in-situ cleaning module by conducting experiments using 300mm tetraethyl orthosilicate (TEOS) blanket wafers. This study also explores brush pre-treatment in the CMP tool and proposes recipe effects, and critical process parameters for optimized CMP in-situ cleaning process through experimental results.

• 한국전기전자재료학회논문지
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• 제22권2호
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• pp.114-118
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• 2009

PVA (polyvinyl alcohol) brush cleaning method is a typical cleaning method for semiconductor cleaning process especially post-CMP cleaning. PVA brush contacts with the wafer surface and abrasive particle, generating the contact rotational torque of the brush, which is the removal mechanism. The brush rotational torque can overcome theoretically the adhesion force generated between the abrasive particle and wafer by zeta potential. However, after CMP (chemical mechanical polishing) process, many particles remained on the wafer because the brush was contaminated in previous post-CMP cleaning step. The abrasive particle on the brush redeposits to the wafer. The level of the brush contamination increased according to the cleaning run time. After cleaning the brush, the level of wafer contamination dramatically decreased. Therefore, the brush cleanliness effect on the cleaning performance and it is important for the brush to be maintained clearly.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2007년도 하계학술대회 논문집 Vol.8
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• pp.557-557
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• 2007

최근 Ruthenium (Ru)은 높은 화학적 안정성, 누설전류에 대한 높은 저항성, 저유전체와의 높은 안정성 등과 같은 특성으로 인해 캐패시터의 하부전극으로 각광받고 있다. 이렇게 형성된 Ru 하부전극은 각 캐패시터간의 분리와 평탄화를 위해 CMP 공정이 도입되게 되었다. 이러한 CMP 공정후에는 화학적 또는 물리적 상호작용에 의해 웨이퍼 표면에 오염물이 발생할 수 있다. CMP 공정중에 공급되는 슬러리에는 부식액, pH 적정제, 연마입자등이 첨가되는데 이때 사용된 연마입자는 CMP 공정후 입자오염을 유발할 수 있다. 그러므로, CMP 공정후에는 이러한 오염으로 인해 cleaning 공정이 반드시 필요하게 되었다. 하지만, Post Ru CMP cleaning에 대한 연구는 아직 미비한 상태이다. 그리하여 본 연구에서는 post Ru CMP cleaning에 대한 연구와 cleaning solution 그리고 첨가제에 따른 영향을 살펴보았다.

• 대한화학회지
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• 제47권6호
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• pp.608-613
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• 2003

Post-Oxide CMP(Chemical-Mechanical Polishing) 결과 실리콘 웨이퍼를 오염 시키고 있는 슬러리 입자의 세정 가능성을 조사하기 위하여DHF(Diluted HF)에 비이온성 계면 활성제인 PAAE(Polyoxyethylene Alkyl Aryl Ether), 비양성자성 용제인 DMSO(Dimethylsulfoxide) 와 초순수의 혼합물인 새로운 세정액을 제조하였다. 세정력을 평가하기 위해서 세정제 내에서 각각 다른 제타 포텐셜을 갖는 실리카($SiO_2$), 알루미나($Al_2O_3$)와 PSL(polystylene latex) 입자를 실리콘 웨이퍼 표면의 산화막에 인위적으로 오염시킨 후 실험에 이용하였다. 초음파하에서 세정액의 성능 평가 결과 본 세정기술은 효과적인 입자의 세정능력과 금속이온에 대한 세정 능력을 나타내고 있음을 확인하였다. 즉 기존의 APM($NH_4OH,\;H_2O_2$와 D.I.W의 혼합물)과 달리 상온에서 세정이 가능하고 세정과정이 단축 되었으며, 낮은 농도의 HF를 사용함으로써 최소의 에칭에 의하여 표면 거칠기를 감소시킬 수 있음을 보여주고 있다. 또한 주요 CMP 금속 배선 물질들에 대한 낮은 부식력으로 기존의 CMP 후 세정공정에 뿐만 아니라 차세대CMP 공정으로 각광 받고 있는 Copper CMP 에 대한 Brush 세정 공정의 보조 세정제로 본 세정제가 적용될 가능성이 있음을 확인하였다.

• 대한기계학회논문집A
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• 제33권10호
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• pp.1023-1028
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• 2009

Cleaning is required following CMP (chemical mechanical planarization) to remove particles. The minimization of particle residue is required with each successive technology generation, and the cleaning of wafers becomes more complicated. In copper damascene process for interconnection structure, it utilizes 2-step CMP consists of Cu and barrier CMP. Such a 2-steps CMP process leaves a lot of abrasive particles on the wafer surface, cleaning is required to remove abrasive particles. In this study, the chemical mechanical cleaning(CMC) is performed various conditions as a cleaning process. The CMC process combined mechanical cleaning by friction between a wafer and a pad and chemical cleaning by CMC solution consists of tetramethyl ammonium hydroxide (TMAH) / benzotriazole (BTA). This paper studies the removal of abrasive on the Cu wafer and the cleaning efficiency of CMC process.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2008년도 추계학술대회A
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• pp.1880-1884
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• 2008

Cleaning is required following CMP (chemical mechanical planarization) to remove particles. The minimization of particle residue is required with each successive technology generation, and the cleaning of wafers becomes more complicated. In copper damascene process for interconnection structure, it utilizes 2-steop CMP consists of Cu CMP and barrier CMP. Such a 2-steps CMP process leaves a lot of abrasive particles on the wafer surface, cleaning is required to remove abrasive particles. In this study, the buffing is performed various conditions as a cleaning process. The buffing process combined mechanical cleaning by friction between a wafer and a buffing pad and chemical cleaning by buffing solution consists of tetramethyl ammonium hydroxide (TMAH)/benzotriazole(BTA).

• 반도체디스플레이기술학회지
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• 제15권4호
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• pp.73-78
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• 2016

Contact pressure distribution between PVA brush and semiconductor wafer was measured by developing a test setup which could simulates the post CMP cleaning process. The test set-up used thin film type pressure sensor which could measure the pressure distribution of contact area with the resolution of $15.5ea/cm^2$. As the experimental results, it was verified that there had been severe contact pressure non-uniformity along the axis of the brush and between the adjacent projections on the brush's surface. These results should be considered when developing post CMP cleaning stage or designing the PVA brush.

• 한국재료학회지
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• 제19권3호
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• pp.174-178
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• 2009

The effects of post-CMP cleaning on the chemical and galvanic corrosion of copper (Cu) and titanium (Ti) were studied in patterned silicon (Si) wafers. First, variation of the corrosion rate was investigated as a function of the concentration of citric acid that was included in both the CMP slurry and the post-CMP solution. The open circuit potential (OCP) of Cu decreased as the citric acid concentration increased. In contrast with Cu, the OCP of titanium (Ti) increased as this concentration increased. The gap in the OCP between Cu and Ti increased as citric acid concentration increased, which increased the galvanic corrosion rate between Cu and Ti. The corrosion rates of Cu showed a linear relationship with the concentrations of citric acid. Second, the effect of Triton X-$100^{(R)}$, a nonionic surfactant, in a post-CMP solution on the electrochemical characteristics of the specimens was also investigated. The OCP of Cu decreased as the surfactant concentration increased. In contrast with Cu, the OCP of Ti increased greatly as this concentration increased. Given that Triton X-$100^{(R)}$ changes its micelle structure according to its concentration in the solution, the corrosion rate of each concentration was tested.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2007년도 추계학술대회 논문집
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• pp.529-529
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• 2007

Ruthenium (Ru) is a white metal and belongs to platinum group which is very stable chemically and has a high work function. It has been widely studied to apply Ru as an electrode material in memory devices and a Cu diffusion barrier metal for Cu interconnection due to good electrical conductivity and adhesion property to Cu layer. To planarize deposited Ru layer, chemical mechanical planarization(CMP) was suggested. However, abrasive particle can induce particle contamination on the Ru layer surface during CMP process. In this study, zeta potentials of Ru and interaction force of alumina particles with Ru substrate were measured as a function of pH. The etch rate and oxidation behavior were measured as a function of chemical concentration of several organic acids and other acidic and alkaline chemicals. PRE (particle removal efficiency) was also evaluated in cleaning chemical.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2006년도 추계학술대회 논문집 전기물성,응용부문
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• pp.103-104
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• 2006

$Pb(Zr,Ti)O_3(PZT)$ is very attractive ferroelectric materials for ferroelectric random access memory (FeRAM) applications because of its high polarization ability and low process temperature. However, Chemical Mechanical Polishing (CMP) pressure and velocity must be carefully adjusted because FeRAM shrinks to high density devices. The contaminations such as slurry residues due to the absence of the exclusive cleaning chemicals are enough to influence on the degradation of PZT thin film capacitors. The surface characteristics of PZT thin film were investigated by the change of process parameters and the cleaning process. Both the low CMP pressure and the cleaning process must be employed, even if the removal rate and the yield were decreased, to reduce the fatigue of PZT thin film capacitors fabricated by damascene process. Like this, fatigue characteristics were partially controlled by the regulation of the CMP process parameters in PZT damascene process. And the exclusive cleaning chemicals for PZT thin films were developed in this work.