Proximity effect (electron beam lithography)

About: Proximity effect (electron beam lithography) is a research topic. Over the lifetime, 940 publications have been published within this topic receiving 8508 citations.

Proximity effect correction for high‐voltage electron beam lithography

Abstract: A new proximity effect correction method using an approximate dose correction formula has been developed. The method is especially effective for a high acceleration voltage. In the case of an acceleration voltage of 40 kV, the correction error for the energy deposition in the resist was estimated analytically to be less than ±7%. The deviations of the line and space pattern dimensions were also evaluated experimentally to be less than ±0.03 μm. The calculation time for correcting a 4‐Mbit dynamic random access memory (DRAM) was only 0.7 h using a large‐scale computer of 15 MIPS (mega instructions per second). Even if the LSI patterns have no hierarchical structure, in an application specific integrated circuit (ASIC) pattern the calculation time would be 1 h or so. A 4‐Mbit DRAM pattern can be written using the electron beam direct‐writing system EX‐7 with sufficient accuracy. These results suggest that the method is practical.

Proximity effect correction method for mask production

Abstract: A proximity effect correction method for mask production by integrating the electron beam proximity effect correction method and the optical proximity effect correction method such that the problems of having too large a computer-aided design pattern data file during mask production and using the mask to transfer the image to the wafer by a stepper is solved. The correction method of this invention comprises the steps of providing a pattern for forming on a mask, and then dividing the mask area into a plurality of first area patches and a plurality of second area patches, wherein each first area patch contains part of the whole pattern while each second area patch does not contain any pattern. Next, according to pattern density and light contrast, the amount of exposure by electron beam is adjusted such that electron beam proximity effect and optical proximity effect are corrected forming a corrected pattern. Finally, using the corrected pattern, an electron beam exposure operation is carried out to form the mask.

Electron beam transferring mask and manufacture thereof

Abstract: PURPOSE:To enable to perform an electron beam transfer and the correction of proximity effect simultaneously by one transfer process by a method wherein the width of pattern to be formed on a substrate is corrected in proportion to the quantity of back-scattering electron of each region on the sample on which an electron beam transfer is performed. CONSTITUTION:The width of the patterns 2 on a photoelectric mask is formed thicker on the circumferential part and thinner in the center part than that of the pattern 1 to be formed on a sample by performing an electron beam transfer. When an electron beam transfer is performed using the mask such as above-mentioned, the dosage which is received by the resist on the sample becomes the sum of the dosage of the beam projected from the pattern on the mask and that of the back-scattering. As a result, the pattern to be formed on the sample is thickly formed in the center part when compared with that on the cicumferential part. Accordingly, the width of the pattern on the mask is to be formed thinner in the center part than that on the circumferential part. As a result, the pattern to be formed on the sample can be formed equal in width.

Proximity correction and resolution enhancement of plasmonic lens lithography far beyond the near field diffraction limit

Abstract: Near-field optical imaging methods have been suffering from the issue of a near field diffraction limit, i.e. imaging resolution and fidelity depend strongly on the distance away from objects, which occurs due to the great decay effect of evanescent waves. Recently, plasmonic cavity lens with off-axis light illumination was proposed as a method for going beyond the near field diffraction limit for imaging dense nanoline patterns. In this paper, this investigation was further extended to more general cases for isolated and discrete line patterns, by enhancing the resolution and correcting the proximity effect with assistant peripheral groove structures. Experiment results demonstrate that the width of single, double and multiple line patterns is well controlled and the uniformity is significantly improved in lithography with a 365 nm light wavelength and 120 nm working distance, being approximately ten times the air distance defined by the near field diffraction limit. The methods are believed to find applications in nanolithography, high density optical storage, scanning probe microscopy and so forth.