Kazuya Kadota

Analysis for effects of mask defects to resist pattern using a three‐dimensional photolithography simulator

A three‐dimensional (3D) photolithography simulator was developed which is composed of the two‐dimensional (2D) mask aerial image simulator, simulator for 2D intensity pattern in aligner (STIPAL), and the 3D resist image simulator, resist process 3D simulator (RESPROT). STIPAL can calculate the mask aerial image in projection printing considering lens aberrations and reticle defects which are very important factors influencing submicron pattern transfer, in addition to the parameters of lens NA (numerical aperture), source wavelength λ, partial coherency σ and defocusing. RESPROT can simulate the 3D resist image in a conventional resist process and contrast enhancement lithography (CEL) using the mask aerial image data calculated by STIPAL. Resist pattern printability or fidelity in the submicron process can be analyzed by these simulators. Resist linewidth shifts caused by reticle defects and lens aberrations were analyzed. Effects of a dark defect (a surplus pattern) or a clear defect (a lack of pattern...

Microwave Plasma Etching of Silicon Dioxide for Half-Micron ULSIs

A new Si02 etching technology for half-micron IILSIs has been developed using the microwave plasma etcher. The optimum conditions for SiO2 etching are obtained, in terms of etch rate, geometrical controllability, and radiation damage by fully utilizing such advantages of the microrrave plasma etcherr BS independent control of ion energy and plasma density in low pressure regions. The condition for high selectivity is also found in the 1ow pressure region with C+Fg/CH3F. The technology has been successfully applied to the formation of contact holes down to 0.4 Um with an aspect ratio of 6.

Resist Pattern Analysis For Submicron Feature Size Using 3-D Photolithography Simulator

Photolithography has been used for manufacturing LSIs for a long time and it also becomes a key technology for submicrometer VLSIs. Three dimensional photolithography simulator, RESPROT, has been developed, and reported its concept and application data at the last SPIEs symposium, Vol : 922-02. In this paper RESPROT was improved to simulate optical aberrations, proximity effects and repeatable reticle defects which are remarkably important process factors on submicrometer pattern transfer. And resist pattern printability or fidelity were studied. At first three dimensional simulator, RESPROT, was improved for the quantitative calculation of higher order reduction lens aberrations and contrast enhance layer, CEL, for resist images. It was confirmed by the calculations that there is existent sixth order aberration and critical dimension loss was decreased by using of CEL. For proximity effect it is slightly improved by higher numerical aperture, NA, but resist images are deformed on defocusing. Printability of submicron reticle defects are depend on the defect type ; clear or dark defects. Both defects decrease imaged resist sizes on defocusing, but these are transferred more clearly on higher NA imaging. Also reticle defects are printed with more faithful by optical aberrations.

Novel indices characterizing resolution power of photoresist for half-micron feature size photolithography

The photoactive and development parameters of commercially available g‐line photoresists which are TOKs OFPR800, OFPR5000, TSMR8900, and TSMR‐V3, were measured. From the simulated and experimental linewidth linearity data, it was found that the photoactive parameters have very little effect on the resolution power (linearity limit) of photoresists, while the development parameters (dissolution rate characteristics) greatly affect the resolution power. New indices, which can properly characterize the resolution power of photoresists, were extracted from the dissolution rate characteristics curves. One is Cd, which is the contrast of the dissolution rate and the other is Rd, which is the range of the dissolution rate. These indices are closely related to the resist resolution power. A larger Cd or Rd gives a higher resolution power to the photoresist. The necessary value of Cd⋅Rd for the 0.5‐μm feature size photolithography process was derived from experimental data under the present highest NA(=0.55) g‐lin...

New indexes of the 0.5-μm resolution resist for optical lithography

New indexes to evaluate and simulate the resolution power of the UV resists based on the dissolution rate curve as it relates to local inhibitor concentration are proposed. Optical parameters and the dissolution rate curve of commercially available resists were measured and studied to show their effect on the resolution power. The optical parameters A B and C had very little effect on the resolution power while the dissolution rate curve greatly effected the resolution power. Two indexes are extracted from the dissolution rate curve. One is the contrast of the dissolution rate and the other is the range of the dissolution rate. By using these indexes the resolution power can be easily described. The indexes of an imaginary resist required for a 0. 5. tm process is shown. 1 .