In the latest ITRS roadmap updated in July 2010, Maskless remains identified as one of the candidate to address lithography needs for the sub-16nm technology nodes. The attractiveness of this solution in terms of cost and flexibility linked to the throughput potential of the massively parallel writing solutions maintain the interest of large scale IC manufacturers, such as TSMC(1) and STMicroelectronics, to push the development of this technology. In July 2009, LETI and MAPPER have initiated an open collaborative program IMAGINE focused on the assessment of the MAPPER technology. This paper reports on the key results obtained during this first assessment year in terms of: resolution capabilities, stitching performances, technology reliability and infrastructure development. It also provides an extensive overview on the maturity degree and the ability of this low energy accelerating voltage multibeam option to answer to the industry needs in the 2015 horizon.
With the willingness of the semiconductor industry to push manufacturing costs down, the mask
less lithography solution represents a promising option to deal with the cost and complexity concerns
about the optical lithography solution. Though a real interest, the development of multi beam tools still
remains in laboratory environment. In the frame of the seventh European Framework Program (FP7), a
new project, MAGIC, started January 1st 2008 with the objective to strengthen the development of the
mask less technology. The aim of the program is to develop multi beam systems from MAPPER and
IMS nanofabrication technologies and the associated infrastructure for the future tool usage. This paper
draws the present status of multi beam lithography and details the content and the objectives of the
MAGIC project.
Molecular resist have potential interest for low CDs and LERs required in future lithography
technology. The lithographic ability of one of them is exposed in this study, by e-beam and by EUV-IL. Work
on process condition is described and leads to dense-lines resolution down to 32.5nm for.
In this study, it is investigated how chemical modifications of a given resist platform can induce improvements in e-beam lithographic performances. Molecular weight (Mw) as well as photo-acid generator (PAG) modifications will act as fine tuners for Sumitomo NEB-33 negative resist to match specific applications: preparation of advanced CMOS R&D architecture (highly resolving resists needed) and fast patterning for production environment (highly sensitive resists needed).
Laurent Pain, C. Gourgon, K. Patterson, B. Scarfogliere, Serge Tedesco, Gilles Fanget, B. Dal'zotto, M. Ribeiro, Tadashi Kusumoto, Masumi Suetsugu, Ryotaro Hanawa
Chemical Amplification Resists (CAR) are now widely used in optical lithography since the introduction of the deep UV era. One advantage of the CARs is also their full compatibility with electron beam writing. This paper is focused on the development work of a negative tone resist. The influence of resist compounds such as polymer matrix composition and PAG size on diffusion and ultimate resolution is detailed. Finally the pattern transfer capabilities of a 30 nm isolated line into a polysilicon layer is presented.
This paper presents the process optimization study of negative tone Chemically Amplified Resists (CAR) under E-Beam exposure. The importance of post apply bake temperature choice on resolution is underlined. The process study determines the process window in which optimal conditions of both post apply and post exposure bake steps are defined and present a method to define more precisely the thermal cross-linking onset. Finally lithographic performances of CARs are studied and we show that resolution can be pushed down to 40 nm.
Olivier Joubert, C. Martinet, Jacques Pelletier, Michel Pons, Jean-Marc Francou, Jean-Pierre Panabiere, Andre Weill, Serge Tedesco, Francoise Vinet, Thierry Mourier
A parametric study of the pattern transfer step in a trilevel resist system using oxygen-based plasmas has been made using a distributed electron cyclotron resonance reactor with independent rf biasing. In pure oxygen plasmas, critical dimension loss is always present in the O2 pressure and ion bombardment energy ranges investigated. The mechanisms most likely to be responsible for these defects during the pattern transfer process are presented and discussed. Perfect anisotropy can only be obtained at substrate temperatures below -60 degree(s)C. A novel plasma etching process based on sidewall passivation by sulfur is proposed using SO2/O2 mixtures. Perfect anisotropy without critical dimension loss is obtained at room temperature by using an 80% SO2/20% O2 mixture and a moderate ion bombardment energy. The ultimate resolution using this new plasma process in conjunction with deep UV exposure and a phase-shift mask is presented.
Dry developable lithography as represented by the DESIRE process, is one of the most attractive surface imaging technologies for advanced optical lithography. A resolution of 0.25 micrometers has been demonstrated with this process, using i-line exposure in conjunction with a phase shifting mask and by deep-UV exposure (248 nm). Surface imaging is especially suited for deep-UV lithography since it overcomes the poor CD-control over topography encountered with highly transparent wet developable resists. In this work the applicability of DESIRE to sub-0.5 micrometers processing has been studied. With regard to the silylation process, crosslinking effects resulting from the radiation at 248 nm have been found to reduce the Si incorporation. This crosslinking effect can be reduced by the use of alternative silylating agents (such as TMDS 1,1,3,3-tetramethyl disilazane), which silylate at a lower temperature. A comparison of processing latitudes for lines and for contact holes has been made for silylation with HMDS and with TMDS. Other issues related to the implementation of DESIRE in typical CMOS processing, such as dry etch compatibility and resist stripping have also been addressed.
Polysilicon etching is a critical process for VLSI. Recently1, HBr appeared to be the best choice for a good selectivity versus oxide and a good profile control. In this paper, we investigated a HBr-Cl2 chemistry in a classical RIE system at pressure below 15 Pa. The etching was performed with either resist or oxide masks. Results were optimized through statistical experimental designs. The influence of the different process parameters: power, pressure and gas flows were detailed. Etching of 100nm patterns, stopping within 70A thin gate oxide (even with a long overetch time) was achieved using the developped process.
New development on both positive and negative tone resist allows maskmaking technology to achieve sub half micron fea tures through dry etching process. This paper will demonstrate lOOnm to 200nm lines and spaces maskmaking capability using standard chromium photomask coa ted with single layer resist SAL6O1 from Shipley for negative tone image and PLASI4ASK from UCB Electronics using the PRIME process for positive tone image. Moreover using PRIME a full dry process from resist deve lopment to chromium etching is proposed. An optimized process point for chromium etching using both SAL6O1 and PLASMASK resists obtained by statiscal experimen tal design is proposed. I .
A new positive working system for e-beam lithography, called
PRIME (Positive Resist IMage by dry Etching) is proposed.
High contrast (about 6) and resolution 75 nm L/S in O.351um
thick resist are achieved. Very steep profiles can be obtai-
ned on thick resist even at low accelerating voltage as
O.2pm hole in l.2pm thick resist at 20 keV.
To be able to quantify both intra and inter proximity effect
on positive tone resist specific two layers electric tests
chips were designed.
Then PRIME process has been compared, in terms of proximity
effects magnitude, at 20kV and 50 kV, to RAY-PF resist show-
ing clearly advantages over such three components novolac ba-
sed positive resist.
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