Makoto Nakajima

Approach to hp10nm resolution by applying Dry Development Rinse Process (DDRP) and Materials (DDRM)

EUV lithography has been desired as the leading technology for single nm half-pitch patterning. However, the source power, masks and resist materials still have critical issues for mass production. Especially in resist materials, RLS trade-off is the key issue. To overcome this issue, we are suggesting Dry Development Rinse Process (DDRP) and Materials (DDRM) as the pattern collapse mitigation approach. This DDRM can perform not only as pattern collapse free materials for fine pitch, but also as the etching hard mask against bottom layer (spin on carbon : SOC). In this paper, we especially propose new approaches to achieve high resolution around hp10nm. The key points of our concepts are 1) control PR profiles, 2) new solvent system to avoid chemical mixture, 3) high etching selective DDR materilas and 4) high planar DDR materials. This new DDRM technology can be the promising approach for hp10nm level patterning in N7/N5 and beyond.

Multilayer BARCs for hyper-NA immersion lithography process

Organic Bottom Anti-Reflective Coatings (BARCs) has been used in the lithography process. BARCs may play an important role to control reflections and improve swing ratios, CD variations, reflective notching, and standing waves. In 32-45nm node, application of the immersion lithography technique is not avoided to obtain the high resolution. To obtain the high resolution, numerical aperture (NA) of the optical system needs the Hyper-NA lens of 1.0 or more but come up to the problem of affections the polarized light in the Hyper-NA lens. The substrate of reflection control also will become more difficult by using single BARCs system and the thin film resist becomes the necessity and indispensable at Hyper-NA lithography. To achieve an appropriate reflection control, to suppress the CD difference to the minimum, and to prevent the pattern collapse, hard mask with the spin coating film and antireflection characteristic is needed. In order to solve these issues, we designed and developed new materials with the suitable optical parameter, square resist shape and large dry etching selectivity. These Multi-layer materials of each process are spin-coated by using the current system and conventional ArF photo resist or immersion resist is available in this process. This paper presents the detail of our newest materials for Hyper NA lithography.

Design and development of next-generation bottom anti-reflective coatings for 45nm process with hyper NA lithography

Integrated circuit manufacturers are consistently seeking to minimize device feature dimensions in order to reduce chip size and increase integration level. Feature sizes on chips are achieved sub 65nm with the advanced 193nm microlithography process. R&D activities of 45nm process have been started so far, and 193nm lithography is used for this technology. The key parameters for this lithography process are NA of exposure tool, resolution capability of resist, and reflectivity control with bottom anti-reflective coating (BARC). In the point of etching process, single-layer resist process cant be applied because resist thickness is too thin for getting suitable aspect ratio. Therefore, it is necessary to design novel BARC system and develop hard mask materials having high etching selectivity. This system and these materials can be used for 45nm generation lithography. Nissan Chemical Industries, Ltd. and Brewer Science, Inc. have been designed and developed the advanced BARCs for the above propose. In order to satisfy our target, we have developed novel BARC and hard mask materials. We investigated the multi-layer resist process stacked 4 layers (resist / thin BARC / silicon-contained BARC (Si-ARC) / spin on carbon hard mask (SOC)) (4 layers process). 4 layers process showed the excellent lithographic performance and pattern transfer performance. In this paper, we will discuss the detail of our approach and materials for 4 layers process.

Novel ArF extension technique by applying Dry Development Rinse Process (DDRP) and Materials (DDRM)

ArF lithography is still major process to develop N7/N5 devices. Especially in resist materials, DOF, roughness and CD uniformity are the biggest key parameters in fine pitches. To improve these issues, we newly propose to apply Dry Development Rinse Process (DDRP) and Materials (DDRM) as the ArF extension approach. In EUV lithography, DDRP is already one of the approaches to achieve high resolution. However, the performance of DDRP for ArF lithography was never demonstrated in detail. In this paper, we especially focus to improve DOF, CD uniformity and roughness by applying DDRP for ArF generation. Finally we succeeded to enhance every parameter at the same time by controlling DDRM etching condition. This new DDRP technology can be the promising approach for ArF extension stages in N7/N5 and beyond.

Novel DDR process and materials for front-edge NTD process

We developed the novel process and material which can prevent the pattern collapse issue perfectly. The process was Dry Development Rinse (DDR) process, and the material used in this process was DDR Material (DDRM). DDRM was containing siloxane polymer which could be replaced the space area of the photo resist pattern. And finally, the reversed pattern would be created by dry etching process without any pattern collapse issue. This novel process was useful not only in positive tone development (PTD) process but also in negative tone development (NTD) process. We newly developed DDRM for NTD process. Novel DDRM consist of special polymer and it used organic solvent system. So, new DDRM showed no mixing property with NTD photo resist and it has enough etch selectivity against NTD photo resist. Image reversal was successfully achieved by combination of NTD process and DDR process keeping good pattern quality. Tone reverse pattern below hp 18nm was obtained without any pattern collapse issue, which couldn’t be created by just using normal NTD process.

Development of Si-HM for NTD process

Negative Tone Development (NTD) process with ArF immersion has been developed for the next generation lithography technology because it shows good resolution performance and process window for C/H and trench patterning. Because of the etch requirement, tri-layer process has been used popularly. However, most of the Si-HM materials are optimized for positive tone development process and most of them show poor lithography performance in NTD process. In this paper, we study the behaviors of Si-HM for NTD process, develop new concepts and optimize the formulation of Si-HM to match the resist for NTD process bellow N28 node device.

Advanced development of organic and inorganic under layers for EUV lithography (Conference Presentation)

EUV lithography has been desired as the leading technology for below Hp20nm. However, the source power, masks and resist materials still have critical issues for mass production. Especially in resist materials, RLS trade-off is the key issue. To overcome this issue, we are focusing on Organic & Inorganic Hard Mask as the bottom layer of EUV PR. Especially, Inorganic under layers (Si-HM) can perform not only as the lithographic performance enhancement layer for fine pitch, but also as the etching hard mask against bottom layer (spin on carbon : SOC). In this paper, we especially propose new approaches to achieve high resolution below hp16nm. The key points of our concepts are EUV-sensitive units of Si-HM. This new EUV sensitive Si-HM could resolve Hp14nm L/S pattern with wide DOF margin. It can also perform as the high universal materials in any development process (PTD & NTD) and any PR materials. Moreover, the latest Organic under layers developed for the advanced EUV CAR PR & Metal resist also will be discussed in the paper. From the Organic & Inorganic under layer material design, we will present new concepts to get high resolution in EUVL.

DDR process and materials for novel tone reverse technique

We developed the novel process and material which can be created reverse-tone pattern without any collapse. The process was Dry Development Rinse (DDR) process, and the material used in this process was DDR material. DDR material was containing siloxane polymer which could be replaced the space area of the photo resist pattern. And finally, the reverse-tone pattern could be obtained by dry etching process without any pattern collapse issue. DDR process could be achieved fine line and space patterning below hp14nm without any pattern collapse by combination of PTD or NTD photo resist. DDR materials were demonstrated with latest coater track at imec. DDR process was fully automated and good CD uniformity was achieved after dry development. Detailed evaluation could be achieved with whole wafer such a study of CD uniformity (CDU). CDU of DDR pattern was compared to pre-pattern’s CDU. Lower CDU was achieved and CDU healing was observed with special DDR material. By further evaluation, special DDR material showed relatively small E-slope compared to another DDR material. This small E-slope caused CDU improvement.

DDR process and materials for NTD photo resist toward 1Xnm patterning and beyond

We developed the novel process and material which can prevent the pattern collapse issue perfectly. The process was Dry Development Rinse (DDR) process, and the material used in this process was DDR material. DDR materials were containing siloxane polymer which could be replaced the space area of the photo resist pattern. And finally, the reversed pattern would be created by dry etching process without any pattern collapse issue.

Single-nm resolution approach by applying DDRP and DDRM

EUV lithography has been desired as the leading technology for 1x or single nm half-pitch patterning. However, the source power, masks and resist materials still have critical issues for mass production. Especially in resist materials, RLS trade-off has been the key issue. To overcome this issue, we are suggesting Dry Development Rinse Process (DDRP) and Materials (DDRM) as the pattern collapse mitigation approach. This DDRM can perform not only as pattern collapse free materials for fine pitch, but also as the etching hard mask against bottom layer (spin on carbon : SOC). In this paper, we especially propose new approaches to achieve high resolution around hp1X nm L/S and single nm line patterning. Especially, semi iso 8nm line was successfully achieved with good LWR (2.5nm) and around 3 times aspect ratio. This single nm patterning technique also helped to enhance sensitivity about 33%. On the other hand, pillar patterning thorough CH pattern by applying DDRP also showed high resolution below 20nm pillar CD with good LCDU and high sensitivity. This new DDRP technology can be the promising approach not only for hp1Xnm level patterning but also single nm patterning in N7/N5 and beyond.