Improved Proximity Effect Correction Technique Suitable for Cell Projection Electron Beam Direct Writing System

Tamura, Takao; Nakajima, Ken; Nozue, Hiroshi

doi:10.1143/jjap.33.6953

Cited by 10 publications

(3 citation statements)

References 19 publications

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“…Especially in the case of the CP method, using a high acceleration voltage, this method can be applied to CP EB direct writing using Convoluted El for each array of CP shot areas along the y-axis can be easily calculated (Fig.! ) because the deposited energy saturates enough within one CP shot area [6]. The El CcpAj on an array of the CP shot area Ai from other array of the CP shot area is therefore easily estimated using the convoluted El which is weighted with W, by y-axis.…”

Section: -Dimensional Calculation Methods For Cp Eb Direct Writingmentioning

confidence: 99%

One-dimensional calculation method for proximity effect correction in cell projection electron-beam direct writing

et al. 1997

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Electron beam (EB) direct writing has often been used for advanced device development because the dimensions of the pattern required for advanced device fabrication are below the maximum resolution of applicable optical lithography. Recently, EB direct writing has been put practical use in advanced device production using the cell projection (CP) method, which drastically increases the writing throughput of an EB direct writing system. When CP EB direct writing is used to produce advanced DRAM, however the handling of a large volume of data becomes an important issue. A data preparation system with simple proximity effect correction, which is suitable for the CP method, is therefore required for the reduction of the data preparation time (conversion time). We therefore propose the improved proximity effect correction, which is based on the self-consistent method, using a one dimensional calculation method for CP direct writing. This method can drastically reduce the exposure intensity calculation time because the calculation of a linear integral can be substituted for that of a surface integral. The conversion time to fabricate a O.15j.tm Gbit DRAM (lO.3x iø rectangle patterns) with a CD accuracy within was reduced to be only 10% of original elapsed time. (in conventional 2-D correction method).

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Section: -Dimensional Calculation Methods For Cp Eb Direct Writingmentioning

confidence: 99%

One-dimensional calculation method for proximity effect correction in cell projection electron-beam direct writing

et al. 1997

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“…This causes an error, 21,27 and the error can be considered as a sort of the edge error. Thus, the estimation gives the guideline for the maximum character size.…”

Section: ͑C5͒mentioning

confidence: 99%

Reticle fabrication by high acceleration voltage electron beam: Representative figure method for proximity effect correction [VI]

Abe

1996

Journal of Vacuum Science &Amp; Technology B: Microelectronics and Nanometer Structures Processing, Measurement, and Phenomena

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Proximity effect correction for reticle making by the dose correction method is discussed. A new algorithm for calculating the optimum dose is proposed, which is based on the dose formula method and the representative figure method. Its main feature is that dose evaluation points are fixed at individual small regions whose size is sufficiently small compared with the backscattering range. The calculation speed of the computer is evaluated which is sufficient to suppress the correction time to less than the writing time. The required calculation speed is 500 MIPS×4 CPU at most for a minimum feature size greater than 0.2 μm on the reticle. This result suggests that the real-time proximity effect correction is possible for making reticles. Furthermore, when the algorithm is applied to x-ray mask fabrication and direct writing process, the calculation time can be suppressed to less than the writing time.

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“…1,2 For instance, the dose compensation method, which needs a complicated calculation in order to obtain the correction dose by the self-consistent method 1 or the pattern density method 3 using the exposure intensity distribution ͑EID͒ function, is generally used in 50 kV cell projection lithography. 4,5 The calculation will become more enormous for a higher voltage exposure due to a larger backscattering range. On the other hand, in the SCALPEL technique, 6 the GHOST method is used in which some of electrons scattered by the scatterer on the membrane ͑SCALPEL͒ mask are selectively used to form a correction beam.…”

Section: Introductionmentioning

confidence: 99%

Proximity effect correction by the GHOST method using a scattering stencil mask

Yamashita

Nomura

Manako

et al. 1999

Journal of Vacuum Science &Amp; Technology B: Microelectronics and Nanometer Structures Processing, Measurement, and Phenomena

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Proximity effect correction (PEC) by the SCALPEL GHOST method, using a scattering stencil mask in which mask-scattered electrons are used as a correction beam, is discussed and a new correction dose adjustment method is proposed. We simulate electron scattering in order to trace electron trajectories in the Si membrane and obtain exiting angular distribution by using a Monte Carlo method. We found that the GHOST can be used for a PEC using a Si scattering stencil mask of about 0.3–2 μm thickness under a 100 kV accelerating voltage. In the SCALPEL technique, the correction dose is adjusted by changing the radius of the annular aperture size for different mask conditions and for various under-layer conditions. In the method proposed, the vertical position of an additional correction dose adjustment aperture is shifted. The angular range becomes narrow as the aperture shifts so that the electron transmission determining the correction dose can be corrected in the doublet optics. This method can also be applied to the membrane mask.

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Improved Proximity Effect Correction Technique Suitable for Cell Projection Electron Beam Direct Writing System

Cited by 10 publications

References 19 publications

One-dimensional calculation method for proximity effect correction in cell projection electron-beam direct writing

One-dimensional calculation method for proximity effect correction in cell projection electron-beam direct writing

Reticle fabrication by high acceleration voltage electron beam: Representative figure method for proximity effect correction [VI]

Proximity effect correction by the GHOST method using a scattering stencil mask

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