The phase-shifting mask consists of a normal transmission mask that has been coated with a transparent layer patterned to ensure that the optical phases of nearest apertures are opposite. Destructive interference between waves from adjacent apertures cancels some diffraction effects and increases the spatial resolution with which such patterns can be projected. A simple theory predicts a near doubling of resolution for illumination with partial incoherence σ < 0.3, and substantial improvements in resolution for σ < 0.7. Initial results obtained with a phase-shifting mask patterned with typical device structures by electron-beam lithography and exposed using a Mann 4800 10× tool reveals a 40-percent increase in usuable resolution with some structures printed at a resolution of 1000 lines/mm. Phase-shifting mask structures can be used to facilitate proximity printing with larger gaps between mask and wafer. Theory indicates that the increase in resolution is accompanied by a minimal decrease in depth of focus. Thus the phase-shifting mask may be the most desirable device for enhancing optical lithography resolution in the VLSI/VHSIC era.

Improving resolution in photolithography with a phase-shifting mask

Process gas discharged from a bypass pipe to a gas exhaust system can be prevented from diffusing back to the inside of a process chamber without having to install a dedicated vacuum pump at the downstream side of the bypass pipe. The substrate processing apparatus includes a process chamber accommodating a substrate, a gas supply system supplying process gas from a process gas source to the process chamber for processing the substrate, a gas exhaust system configured to exhaust the process chamber, two or more vacuum pumps installed in series at the gas exhaust system, and a bypass pipe connected between the gas supply system and the gas exhaust system. The most upstream one of the vacuum pumps is a mechanical booster pump, and the bypass pipe is connected between the mechanical booster pump and the rest vacuum pumps located at a downstream side of the mechanical booster pump.

Substrate Processing Apparatus

A method and apparatus for creating a phase shifting mask and a structure mask for shrinking integrated circuit designs. One embodiment of the invention includes using a two mask process. The first mask is a phase shift mask and the second mask is a single phase structure mask. The phase shift mask primarily defines regions requiring phase shifting. The single phase structure mask primarily defines regions not requiring phase shifting. The single phase structure mask also prevents the erasure of the phase shifting regions and prevents the creation of undesirable artifact regions that would otherwise be created by the phase shift mask. Both masks are derived from a set of masks used in a larger minimum dimension process technology.

Phase shifting circuit manufacture method and apparatus

A method for performing design rule checking on OPC corrected or otherwise corrected designs is described. This method comprises accessing a corrected design and generating a simulated image. The simulated image corresponds to a simulation of an image which would be printed on a wafer if the wafer were exposed to an illumination source directed through the corrected design. The characteristics of the illumination source are determined by a set of lithography parameters. In creating the image, additional characteristics can be used to simulate portions of the fabrication process. However, what is important is that a resulting simulated image is created. The simulated image can then be used by the design rule checker. Importantly, the simulated image can be processed to reduce the number of vertices in the simulated image, relative to the number of vertices in the OPC corrected design layout. Also, the simulated image can be compared with an idea layout image, the results of which can then be used to reduce the amount of information that is needed to perform the design rule checking.

Design rule checking system and method

A method and apparatus for the correction of integrated circuit layouts for optical proximity effects which maintains the original true hierarchy of the original layout is provided. Also provided is a method and apparatus for the design rule checking of layouts which have been corrected for optical proximity effects. The OPC correction method comprises providing a hierarchically described integrated circuit layout as a first input (205), and a particular set of OPC correction criteria as a second input (260). The integrated circuit layout is then analyzed to identify features of the layout which meet the provided OPC correction criteria (210, 240). After the areas on the mask which need correction have been identified (310), optical proximity correction data (320) is generated in response to the particular set of correction criteria. Finally, a first program data is generated which stores the generated optical proximity correction data in a hierarchical structure (320) that corresponds to the hierarchical structure of the integrated circuit layout (310). As the output correction data is maintained in true hierarchical format, layouts which are OPC corrected according to this method are able to be processed through conventional design rule checkers with no altering of the data.

Data hierarchy layout correction and verification method and apparatus

In a halftone type phase shift photomask, a patterned halftone layer is formed on a transparent substrate, and a light screen layer is formed on the halftone layer. A part of a mask pattern is changed from opaque to halftone, thus improving the resist pattern fidelity.

Optical proximity correction halftone type phase shift photomask

Disclosed is a photomask in which contrast of light intensity of a pattern to be transferred (main pattern) is enhanced on an image plane while transfer of auxiliary pattern themselves is suppressed. The photomask, which is used in exposure to which is applied four-point illumination method for inverting phase of light that passes through mutually adjacent patterns, has first auxiliary patterns, disposed above and below and to the left and right of a main pattern to be transferred, to thereby provide a transparent substrate with a surface flush with the main pattern or with a difference in level corresponding to a phase difference with respect to the main pattern that is K times 360° (where K is an integer that does not include zero), and second auxiliary patterns disposed at angles of 45° with respect to the main pattern, the second auxiliary patterns providing a difference in level corresponding to a phase difference, with respect to the first auxiliary patterns, that is (2L+1) times 180° (where L is an integer inclusive of zero). The contrast of the first auxiliary patterns is reduced by the second auxiliary patterns, thereby enlarging the depth of focus.

Photomask and exposure method using a photomask

PROBLEM TO BE SOLVED: To obtain desired mask patterns by partially using the effect of a phase shift mask. SOLUTION: The mask patterns are formed of light shielding films 2 and translucent films 3 on a transparent substrate 1. The light shielding films 2 are composed by substituting the ends among the pattern shapes of the intrinsic mask with the translucent films 3. The translucent films 3 have transmittance of about 4 to 15% and give rise to a phase difference of about 180 deg. between the light transmitted therethrough and the light not transmitted therethrough. As a result, the light intensity at the edges of the translucent films 3 is steepened and the degeneracy of the patterns transferred to a photoresist is prevented. Since the light shielding films 2 are partly substd. with the translucent films, the design and production thereof are easy.

Photomask and its production

After forming a light shielding layer 2 of ruthenium in a thickness of 70 nm and a reflection preventing layer 3 of a ruthenium oxide in thickness of 30 nm, and a photosensitive resin layer, a sililated layer is formed by electron beam lithography and sililation. Etching is performed for the photosensitive resin layer, and the reflection preventing layer and the light shielding layer are dry etched using oxygen gas with taking the sililated layer as a mask. By this, dimensional precision of a pattern of a photo mask can be improved.

Photo mask and fabrication process therefor

To improve the depth of focus of isolated windows, large assist feather technique has been proposed This large assist method uses the assist features having almost the same size as main patterns, and the quartz substrate was vertically etched at the assist features These large assist features were not printed on a wafer by mask topography effect; that is, the light intensity at large assist feature was decreased by the scattering effect of the vertical quartz edges In this large assist feature masks, the phase shift angle of an assist feature has large effect on focus latitude We chose two phase shift angles: 180 degrees for small sigma illumination and 360 degrees for annular illumination The performances of two large assist feature masks were evaluated by using a 055 NA, valuable sigma, and KrF excimer laser stepper Moreover, we applied surface insoluble layer to the assist feature method Large assist features having the same size as main patterns were not printed on resist surface for 016 - 02 micrometer windows Wide DOF (08 micrometer) of 016 micrometer window was obtained by using this method

Shinji Ishida

Papers

Optical proximity correction halftone type phase shift photomask

Photomask and exposure method using a photomask

Photomask and its production

Photo mask and fabrication process therefor

Large assist feature phase-shift mask for sub-quarter-micrometer window pattern formation