• Tribology and Lubricants
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• 제34권3호
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• pp.115-122
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• 2018

Chemical mechanical polishing (CMP) is a hybrid processing method in which the surface of a wafer is planarized by chemical and mechanical material removal. Since mechanical material removal in CMP is caused by the rolling or sliding of abrasive particles, interfacial friction during processing greatly influences the CMP results. In this paper, the trend of tribology research on CMP process is discussed. First, various friction force monitoring methods are introduced, and three elements in the CMP tribo-system are defined based on the material removal mechanism of the CMP process. Tribological studies on the CMP process include studies of interfacial friction due to changes in consumables such as slurry and polishing pad, modeling of material removal rate using contact mechanics, and stick-slip friction and scratches. The real area of contact (RCA) between the polishing pad and wafer also has a significant influence on the polishing result in the CMP process, and many researchers have studied RCA control and prediction. Despite the fact that the CMP process is a hybrid process using chemical reactions and mechanical material removal, tribological studies to date have yet to clarify the effects of chemical reactions on interfacial friction. In addition, it is necessary to clarify the relationship between the interface friction phenomenon and physical surface defects in CMP, and the cause of their occurrence.

• Tribology and Lubricants
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• 제38권6호
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• pp.247-254
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• 2022

Chemical mechanical polishing (CMP) is a hybrid surface-polishing process that utilizes both mechanical and chemical energy. However, the recently emerging semiconductor substrate and thin film materials are challenging to process using the existing CMP. Therefore, previous researchers have conducted studies to increase the material removal rate (MRR) of CMP. Most materials studied to improve MRR have high hardness and chemical stability. Methods for enhancing the material removal efficiency of CMP include additional provision of electric, thermal, light, mechanical, and chemical energies. This study aims to introduce research trends on CMP using ultraviolet (UV) light to these methods to improve the material removal efficiency of CMP. This method, photocatalysis-assisted chemical mechanical polishing (PCMP), utilizes photocatalytic oxidation using UV light. In this study, the target materials of the PCMP application include SiC, GaN, GaAs, and Ru. This study explains the photocatalytic reaction, which is the basic principle of PCMP, and reviews studies on PCMP according to materials. Additionally, the researchers classified the PCMP system used in existing studies and presented the course for further investigation of PCMP. This study aims to aid in understanding PCMP and set the direction of future research. Lastly, since there have not been many studies on the tribology characteristics in PCMP, research on this is expected to be required.

• 한국가시화정보학회:학술대회논문집
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• 한국가시화정보학회 2004년도 추계학술대회 논문집
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• pp.48-51
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• 2004

Chemical Mechanical Polishing(CMP) is popularly used in production of semiconductor because of large area polishing ability probability of improvement for more integrated circuit. However, present CMP processing causes some non-uniformity errors which can be critical for highly integrated circuit. Previous studies predict that flow-field of slurry during CMP can create non-uniformity, but no quantitative measurement has conducted. In this study, using PIV, slurry velocity flow-field during CMP is measured by changing the ratio of RPM of pad and carrier with tuned PIV system adequate for small room in CMP machine and Cabot's non-groove pad Epad-A100. The result show that velocity of slurry is majorly determined by pad-rpm and the ratio of between carrier and pad rpm make some changes in streamlines.

• 한국전기전자재료학회논문지
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• 제15권10호
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• pp.838-843
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• 2002

Chemical mechanical polishing(CMP) process has been widely used to planarize dielectric layers, which can be applied to the integrated circuits for deep sub-micron technology. The reverse moat etch process has been used for the shallow trench isolation(STI)-chemical mechanical polishing(CMP) process with conventional low selectivity slurries. Thus, the process became more complex, and the defects were seriously increased. In this paper, we studied the direct STI-CMP process without reverse moat etch step using high selectivity slurry(HSS). As our experimental results show, it was possible to achieve a global planarization without the complicated reverse moat process, the STI-CMP process could be dramatically simplified, and the defect level was reduced. Therefore the throughput, yield, and stability in the ULSI semiconductor device fabrication could be greatly improved.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2005년도 하계학술대회 논문집 Vol.6
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• pp.651-652
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• 2005

Chemical mechanical polishing (CMP) has emerged as the planarization technique of choice in integrated circuit manufacturing. Especially, polishing pad is considered as one of the most important consumables because of its properties. Generally, conventional polishing pad has irregular pores and asperities. If conditioning process is except from whole polishing process, smoothing of asperities and pore glazing occur on the surface of the pad, so repeatability of polishing performances cannot be expected. In this paper, CMP pad with microstructure was made using micro-molding technology and repeatability of ILD(interlayer dielectric) CMP performances and was evaluated.

• Tribology and Lubricants
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• 제38권1호
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• pp.1-7
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• 2022

Chemical-mechanical polishing (CMP) process is a semiconductor process that planarizes a wafer surface using mechanical friction between a polishing pad and a substrate surface during a specific chemical reaction. During the CMP process, polishing pad conditioning is applied to prevent the rapid degradation of the polishing quality caused by polishing pad glazing through repeated material removal processes. However, during the conditioning process, uneven wear on the polishing pad is inevitable because the disk on which diamond particles are electrodeposited is used. Therefore, the abrasion of the polishing pad should be considered not only for the variables during the conditioning process but also when designing the CMP conditioning system. In this study, three design variables of the conditioning system were analyzed, and the effect on the pad wear profile during conditioning was investigated. The three design variables considered in this study were the length of the conditioner arm, diameter of the conditioner disk, and distance between centers. The Taguchi method was used for the experimental design. The effect of the three design variables on pad wear and uniformity was assessed, and new variables used in conditioning system design were proposed.

• 대한전기학회논문지:전기물성ㆍ응용부문C
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• 제50권9호
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• pp.438-443
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• 2001

In the shallow trench isolation(STI)-chemical mechanical polishing(CMP) process, the key issues are the optimized thickness control, within-wafer-non-uniformity, and the possible defects such as pad oxide damage and nitride residue. The defect like nitride residue and silicon (or pad oxide) damage after STI-CMP process were discussed to accomplish its optimum process condition. To understand its optimum process condition, overall STI related processes including reverse moat etch, trench etch, STI fill and STI-CMP were discussed. Consequently, we could conclude that law trench depth and high CMP thickness can cause nitride residue, and high trench depth and over-polishing can cause silicon damage.

• Tribology and Lubricants
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• 제33권6호
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• pp.282-287
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• 2017

SU-8 is an epoxy-type photoresist widely used for the fabrication of high-aspect-ratio (HAR) micro-structures in micro-electro-mechanical systems (MEMS). To fabricate highly integrated structures, chemical mechanical polishing (CMP) has emerged as the preferred manufacturing process for planarizing the MEMS structure. In SU-8 CMP, an oxidizer decomposes organic impurities and particles in the CMP slurry remove the chemically reacted surface of SU-8. To fabricate HAR microstructures using the CMP process, the adhesion between SU-8 and substrate material is important to avoid the delamination of the SU-8 film caused by the mechanical-dominant material removal characteristic. In this study, the friction force during the CMP process is measured with a CMP monitoring system to detect the delamination phenomenon and investigate the delamination of the SU-8 film from the silicon substrate under various pressure conditions. The increase in applied pressure causes an increase in the frictional force and wafer-edge stress concentration. The frictional force measurement shows that the friction force changes according to the delamination phenomenon of the SU-8 film, and that it is possible to monitor the delamination phenomenon during the SU-8 CMP process. The delamination at a high applied pressure is explained by the effect of stress distribution and pad deformation. Consequently, it is necessary to control the pressure of polishing, which can avoid the delamination in SU-8 CMP.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 1999년도 춘계학술대회 논문집
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• pp.501-504
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• 1999

In the shallow trench isolation(STI) chemical mechanical polishing(CMP) process, the key issues are the optimized thickness control within- wafer-non-uniformity, and the possible defects such as nitride residue and pad oxide damage. These defects after STI CMP process were discussed to accomplish its optimum process condition. To understand its optimum process condition, overall STI related processes including reverse moat etch, trench etch, STI filling and STI CMP were discussed. It is represented that the nitride residue can be occurred in the condition of high post CMP thickness and low trench depth. In addition there are remaining oxide on the moat surface after reverse moat etch. It means that reverse moat etching process can be the main source of nitride residue. Pad oxide damage can be caused by over-polishing and high trench depth.

• 한국정밀공학회지
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• 제17권1호
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• pp.179-184
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• 2000

Chemical Mechanical Polishing (CMP) refers to a material removal process done by rubbing a work piece against a polishing pad under load in the presence of chemically active and abrasive containing slurry. CMP process is a combination of chemical dissolution and mechanical action. The mechanical action of CMP involves hydrodynamic behavior. The liquid slurry is trapped between the work piece and pad forming a hydrodynamic film. For the first step to understand material removal mechanism of the CMP process, the hydrodynamic analysis is done with semiconductor wafer. Three-dimensional Reynolds equation is applied to get pressure distribution of the slurry film. Shear stress distributions on the wafer surface are also analyzed