ICPT 2015 Minutes: Latest Advances in CMP Technology

2015 The annual ICPT Conference (International Conference on Planarization/CMP Technology) was held from September 30 to October 2, 2015, in Phoenix, USA. This conference served as a premier international forum for exchanging ideas on chemical-mechanical polishing (CMP) and planarization technologies. Researchers and engineers from around the world gathered to discuss key issues in the planarization process, engage in extensive technical exchanges, and share valuable information.

This meeting includes: 2 The invited reports are from GlobalFoundries Inc., specifically: Mark Dougherty The invited report titled “Welcome to the Fifth Dimension,” and has already been from IBM Retired Klaus Beyer The problem is titled « IBM In device applications CMP “Discovering Dynamics,” and 9 A special seminar, including: 50 A series of oral presentations and 59 A posted report. Participants discussed semiconductors... CMP Applications, Emerging CMP and integration, CMP defects, cleaning, modeling, CMP Mechanism study, CMP Extensive and in-depth technical exchanges and discussions were held on a wide range of cutting-edge issues, including equipment, consumables, and more. Next, we will briefly introduce the contents of the report in conjunction with its content. CMP The latest advances in technology.

One,        In semiconductors CMP Application

In the trend toward ever-smaller feature sizes, we propose addressing advanced nodes. CMP Technical development requirements and discussion of the practical applications of corresponding technologies. Fujifilm of the Abhudaya Mishra 、 IMEC of the Patrick Ong Micron's Rutuparna Narulkar 、 Air Products of the James Schlueter and Hitachi Chemical of the Yasuhiro Ichige For different devices CMP the requirements, analyze the future CMP Trends in application.

Fujifilm of the Abhudaya Mishra The report points out that, FinFET of the device CMP In polishing different media, different reaction enhancers or inhibitors need to be added to the polishing slurry. During polishing, it is important to pay attention to factors such as removal rate, selectivity, post-polishing surface morphology, and defects.

IMEC of the Patrick Ong Based on experimental results from five different polishing pads and burnishing tools, the researchers have identified the optimal polishing pad combination, which can achieve wafer planarization within a reasonable time frame, effectively control oxide loss, and maintain an appropriate removal rate for bare wafers as well as minimize defects. For... Ge As for the polishing of blank wafers, there is currently no suitable endpoint detection method available, but for... SiGe Empty chip and Ge For the polishing of graphic images, an effective endpoint detection method can be found.

Micron's Rutuparna Narulkar Others pointed out the next generation. 3D NAND The challenges faced by memory devices during polishing include removal rate, flattening of the oxide layer, uniformity within the wafer and across chips, degree of etching, and defect control.

Air Products of the James Schlueter Experts pointed out that the polishing slurry for the next-generation barrier layer requires stricter control over the polishing process and lower defect levels. Experiments have demonstrated that by adding appropriate additives to the barrier-layer polishing slurry, it is possible to enhance the efficiency of mechanical material removal, thereby increasing the removal rate, improving selectivity, achieving better control over the post-polishing surface morphology, and reducing defects.

Hitachi Chemical of the Yasuhiro Ichige Others obtained [something] for [purpose] via electrochemical methods. Co-H₂ O The system's three dimensions pH The polarization curve can provide conventional information such as the corrosion rate. Pourbaix The graph cannot provide useful information, and it can be extended to a multi-dimensional graph of corrosion rates based on the actual polishing process and conditions.

II.        Emerging CMP And integration

As the semiconductor industry develops, feature sizes are becoming increasingly smaller. CMP As an indispensable part of this, it also proposes considerations for advanced nodes. CMP Technical development requirements. In the context of shrinking feature sizes, emerging... CMP The application of technology has received widespread attention and research. Zhang Baoguo from Hebei University of Technology and Wang Jie from Tsinghua University, Entegris of the Chintan Patel 、 Kyushu University and Ebara of the Masashi Kitamura Made and shared the corresponding report.

Zhang Baoguo and colleagues from Hebei University of Technology have been attempting to improve [something] by using different chemical solutions and abrasive particle sizes. Gallium nitride the removal rate, and ultraviolet light is incorporated into its polishing process. With the advancement of plasma technology, it is possible to... Gallium nitride Plasma is introduced during the polishing process or in the pre-treatment stage.

Wang Jie and others from Tsinghua University, based on... H ₂ O ₂-SiO₂  systemic   Gallium nitride The introduction of photocatalytic oxidation technology into the polishing process has been experimentally proven to be highly effective in enhancing removal efficiency. Furthermore, by testing various catalysts, it has been demonstrated that... TiO ₂ It exhibits better catalytic performance, and furthermore, a photocatalytic oxidation system has been established. Gallium nitride Physical model of removal.

Kyushu University and Ebara of the Masashi Kitamura Researchers have demonstrated that the cleanliness of a polishing pad’s surface can be characterized by the clogging ratio, which can be determined from images of the polishing pad. Meanwhile, the effect of the dresser can also be reflected by the clogging ratio.

Entegris of the Chintan Patel People, through the enhancement and innovation of materials, are working on... CMP Processes such as consumables, filtration, and cleaning have been improved, paving the way for the future. 10nm The following CMP The process provides an effective solution.

Three,        CMP Defects, cleaning, modeling

CMP As an indispensable component of the entire semiconductor manufacturing process, studying the causes of defects generated during this process can effectively prevent or reduce defects and enhance the efficiency of the entire production and manufacturing stage. On the other hand, cleaning technology significantly influences the process quality of each semiconductor fabrication step—naturally. CMP The subsequent cleaning process is also a key focus of research; and the research... CMP Currently, this approach relies more heavily on modeling and simulation, and this area also represents an important direction for future development. Wei-Tsu Tseng 、 Ruben Ghulghazaryan Texas Instruments' Christopher Eric Brannon 、 Yohei Hashimoto Wen Jialin from Tsinghua University and others presented reports and shared insights on defects, cleaning, and modeling, respectively.

Yohei Hashimoto People established CMP The contact model for the rough surface of the polishing pad during the process was analyzed, and the surface topography of the polishing pad after use was examined. Taking into account the topographical features, a new contact model was developed by combining the Hertz elastic contact model. However, the contact pressure calculated based on the new model differs significantly from that obtained using the conventional model.

Wei-Tsu Tseng Researchers have demonstrated through experiments that, during the cleaning process following polishing, one should not only take into account the acidity or alkalinity of the cleaning solution but also consider... pH Factors such as value, dilution ratio, hydrogen peroxide concentration, and additives.

Texas Instruments' Christopher Eric Brannon Others have developed the third-generation low [product/technology] through experimentation. pH Adding chemical components during the cleaning process after copper polishing can reduce costs while maintaining the same yield rate.

Ruben Ghulghazaryan People established FEOL CMP model, and explain how it can be used to establish... STI ， POP ， At RMG FEOL Waiting for CMP Models—these models can predict certain relevant data, making it possible to study multi-layer stacking and chip design.

Wen Jialin and colleagues from Tsinghua University used the method of chemical reaction molecular dynamics simulation to conduct their research. Yes During the polishing process, we analyzed the chemical and mechanical synergistic effects of water molecules involved, and investigated the role of polishing pressure. Higher pressure causes more silicon atoms to detach from the surface. This is... ReaxFF Molecular dynamics simulation for the first time in CMP Applications in the field.

Four,        CMP Mechanism Study

As feature sizes continue to shrink, it is inevitable that this will impact the future. CMP Make some new definitions and study under the new nodes. CMP Mechanism, which helps reveal its essence and better serve... CMP The development of the industry. Duane Boning 、  Julianne Truffa 、  Clarkson of the university Armin Saeedi Vahdat 、  Arizona of the university Changhong Wu and Lauren M. Jacobson Wait for the new one CMP The mechanism was presented in a report.

Duane Boning Others have studied. Pad-in-a-Bottle The model, compared to the traditional one CMP It can improve uniformity within the chip, and in the future, we can also explore the possibility of adjusting the removal rate and reducing defects.

Julianne Truffa Others have studied the chemical and physical interactions at the nanoparticle-polymer interface to gain a deeper understanding of advanced... CMP Filtration mechanism. The efficiency of polymer removal depends on pore size and the nature of the polymer itself. Adding additives to the system can reduce the filter's lifespan and impair particle retention. These effects can lead to certain chemical losses during the filtration process, thereby affecting performance. CMP Process.

Clarkson of the university Armin Saeedi Vahdat The researchers developed a mathematical model to describe the trajectories of abrasive particles, thereby investigating the material removal morphology and uniformity under rotary polishing conditions. The model examines the effects of polishing pad conditioning and continuous polishing fluid flow on the distribution and trajectories of abrasive particles.

Arizona of the university Changhong Wu Researchers have studied a thermal management system for the surface of polishing pads, which improves the copper polishing removal rate and in-wafer uniformity by locally regulating the temperature of the polishing pad surface. The study shows that it is possible to reduce the temperature in the central region of the wafer while keeping the temperature in the peripheral region unchanged. As a result, the removal rate in the central region of the wafer drops significantly, whereas the removal rate at the edges remains stable, thereby enhancing the overall in-wafer uniformity.

Lauren M. Jacobson For others to use FCS (Fluorescence Correlation Spectroscopy) technology characterizes abrasive particles in polishing liquids and discusses... FCS The application of technology in the surface chemical properties of silica sol and other abrasive particles.

Five,        New planarization technology

CMP As a global planarization technique, it has been widely adopted in the semiconductor manufacturing industry. However, beyond this, there are many other polishing methods available. By studying these techniques and comparing them with... CMP By integrating these approaches, we believe that further innovations can be proposed for the polishing process in future semiconductor manufacturing. CEA LETI of the Viorel Balan 、 Ozyegin of the university G. Bahar Basim 、 Dan Trojan and Paul Westerhoff A report was shared on the new planarization technology.

CEA LETI of the Viorel Balan The person introduced how to achieve 3D Structural CMP The processes and challenges that need to be faced include: 3D Door structure, 3D Single-chip integrated circuit, and 3D Hybrid direct bonding, etc.

Ozyegin of the university G. Bahar Basim Waiting for people to... CMP Technology has introduced the process of dental implantation, through which... CMP To induce You The microstructure on the surface enhances flatness while simultaneously forming a protective oxide layer, thereby creating a more biocompatible surface. Biocompatibility studies have demonstrated that... CMP The use of oxidizing agents during the process can enhance surface flatness and better facilitate cell adhesion.

Dan Trojan Others are using a new temporary bonding method, using 100mm Advanced silicon polishing equipment, combined with stress testing, has achieved a thickness of... 15um silicon wafers.

Paul Westerhoff People discussed. CMP The properties of polishing liquids containing dispersed particles, including physical, chemical, and in vitro toxicity characteristics.

Six,        CMP Equipment and Measurement

In to CMP As technological research continues to deepen, researchers have discovered that enhancing... CMP Post-effects, in addition to placing higher demands on consumable performance, also involve... CMP The demands on hardware devices and real-time measurement are also becoming increasingly high. Kwangehee Han 、 Keisuke Suzuki 、 Eiichi KONDOH 、 Carlo Dominic Aparece And Mei Guang's Andrew Carswell The corresponding equipment and measurement technologies are introduced, covering applications such as surface morphology and endpoint detection techniques.

Kwangehee Han People use wireless vibration sensors to detect. CMP The signals from the surface of the rotating motor of the equipment’s polishing head are collected during each polishing pad’s service cycle to acquire vibration signals. The relationships among these signals, the process endpoint time, and factors such as the roughness of the polishing pad surface are analyzed.

Keisuke Suzuki Researchers used an evaluation method based on optical Fourier transformation to study the surface topography of polishing pads. By varying the angle of incident light, they were able to measure the polishing pad’s topography under different conditions. After optimizing the angle of incident light, they also achieved a high correlation coefficient—exceeding—between the proportion of wavelength components and the material removal rate. 0.8 ). Therefore, the proportion of wavelength components can be used to evaluate the surface topography of polishing pads.

Eiichi KONDOH Researchers used the elliptical measurement method to quantitatively study particulate contaminants and demonstrated a very strong correlation between elliptical measurements and particle count. This method can be employed in the laboratory to rapidly evaluate the effectiveness of wafer cleaning processes.

Carlo Dominic Aparece Others have integrated the refractive index measurement method into... CMP Among them, refractive index measurement can be applied to the analysis of opaque mixtures and provides valuable information on the various materials mixed in polishing liquids. According to the experimental results, the refractive index measurement method is suitable for... fabulous The system provides sufficient stability for long-term, uninterrupted monitoring of the polishing liquid.

Micron's Andrew Carswell Others have studied optical endpoint detection technologies, including extending the spectral visibility of short-wavelength light and improving the window properties of polishing pads to achieve better endpoint detection. In addition, they have combined motor torque-based endpoint detection technology to investigate how reducing frictional forces can minimize membrane wear.

Seven,        CMP Consumables

CMP Consumable technology primarily refers to... CMP Polishing pads, polishing liquids, dressers, and other items used during the process... CMP Analysis of the impact of the results. At this stage, regarding... CMP The assessment focuses primarily on aspects such as the degree of planarization, technical reliability, and defect-control capability. Among these, defect control—particularly the analysis of factors like scratches, particulates, and corrosion—is a key area of research. Cabot of the Tina C. Li 、 Entegris of the YiWei Lu 、 Chun-Chieh Lee and Jinwoo Park I gave a presentation and shared it.

Cabot of the Tina C. Li The person introduced the company's products. iDIELTM D74XX The polishing liquid boasts advantages such as high planarization efficiency, high oxide removal rate, excellent scratch resistance, and a high dilution ratio, making it suitable for application in... 3D NAND Various applications including non-selective media polishing, selective oxide polishing, and bulk oxide polishing.

Entegris of the YiWei Lu Others have studied. CMP In the filtration process, the screening stage primarily takes place on the surface. Zeta The effect of potential on colloidal particle filtration—high differences. Zeta The potential can enhance filtration efficiency, based on a specific polishing liquid. Zeta Regarding potential performance, researchers can select more suitable materials.

Chun-Chieh Lee Researchers have studied a new additive for silicon polishing slurries that exhibits excellent performance in terms of corrosion resistance and surface roughness, and its material removal rate is adjustable. FinFET advanced CMP Technology is of great significance.

Jinwoo Park Others have studied optimizing the shape of the retaining ring to achieve better uniformity and reduce stress on the edge regions. However, considering the flow rate of the polishing slurry, further research is still needed regarding the positioning of the slots in the retaining ring.

CMP Technological development is advancing rapidly and becoming increasingly complex, while the challenges are mounting. Today, the challenges we face include: 10nm And below CMP Technology, research on new mechanisms, real-time monitoring technologies, exploration and discovery of novel planarization methods, and so forth— CMP It itself also needs to evolve toward automation, refinement, and generalization. In addition to the above-mentioned report, there is also... 59 Participants engaged in poster presentations and exchanges. While listening to inspiring reports, attendees also engaged in in-depth discussions and exchanges during the plenary sessions and breaks, sharing and exchanging a wide range of research findings.