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Photomask blank, photomask and fabrication method thereof

A mask blank and photomask technology, applied in the field of photomasks, can solve the problems of hindering defect inspection, high film reflectivity, and the photomask blank structure cannot satisfactorily satisfy fine photomask patterns, etc. Achieve the effect of increasing dry etching rate, ensuring etching resistance, and reducing thickness

Active Publication Date: 2014-01-22
SHIN ETSU CHEM CO LTD +1
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

However, if SiO 2 film as an etch mask, there will be SiO 2 Problems with excessively high film reflectivity, which hinders defect inspection
[0017] As described above, conventional photomask blank structures cannot satisfactorily meet the demand for forming fine photomask patterns on light shielding films with high precision.

Method used

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  • Photomask blank, photomask and fabrication method thereof
  • Photomask blank, photomask and fabrication method thereof
  • Photomask blank, photomask and fabrication method thereof

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0065] (Example 1: Light-shielding film of photomask blank according to the present invention)

[0066] In order to reduce the thickness of a photoresist used as a mask for forming a photomask pattern, damage to the light shielding film, which is patterned with the photoresist mask, must be reduced during etching of the light shielding film. For this reason, it is necessary to reduce the time required to etch the light shielding film by reducing the physical thickness of the light shielding film to be patterned and / or by increasing the etching rate of the light shielding film.

[0067] The inventor's research proves that increasing the etching rate of the light-shielding film can be achieved by reducing the percentage of metal in the light-shielding film. This means that high-rate etching can be obtained by designing the commonly used chromium-based light-shielding film and reducing the chromium content (percentage) in the light-shielding film.

[0068] For example, when usin...

Embodiment 2

[0120] (Embodiment 2: basic structure of photomask blank)

[0121] Figure 9A is a schematic cross-sectional view for explaining an exemplary structure of a photomask blank according to the present invention, in which a light-shielding film 12 is formed on one principal plane of a transparent substrate 11 made of quartz or the like and used as a photomask substrate superior. The light-shielding film 12 has a layered structure as described above with respect to Embodiment 1, and functions not only as a "light-shielding film" but also as an antireflection film. A film of such a composition is used because it has excellent dry etching properties, electrical conductivity, and chemical resistance.

[0122] In the case where the photomask blank according to the present invention is designed as a mask for making ArF exposure, the thickness and composition of the light-shielding film 12 are selected such that the optical density OD of the light-shielding film 12 for light having a w...

Embodiment 3

[0132] (Embodiment 3: photomask blank, and the first embodiment of patterning process)

[0133] Figure 10 An exemplary arrangement of a film deposition apparatus (sputtering apparatus) used to make a photomask blank according to the present invention is shown, Figures 11A to 11D is a view illustrating an exemplary process of patterning a photomask blank.

[0134] exist Figure 10 In, reference numeral 11 denotes a transparent substrate, which is a 6-inch rectangular quartz substrate. Usually, the surface and end faces of the quartz substrate are finely polished. Reference numeral 101 represents a chamber, reference numeral 102a represents a first target (target), reference numeral 102b represents a second target, reference numeral 103 represents a sputtering gas inlet, reference numeral 104 represents a gas outlet, and reference numeral 105 represents a substrate turntable. A power supply for biasing the first and second targets.

[0135] Both the first target 102a and ...

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Abstract

On one main surface of a transparent substrate (11) such as quartz as a photo mask substrate, a light shielding film (12) is arranged for exposure light. The light shielding film (12) is a so-called 'light shielding film' and may also serve as a reflection preventing film. Moreover, the light shielding film has a film thickness not greater than 100 nm and is designed so that a film thickness of chrome-based compound having an optical density (OD) per unit film thickness for light having a wavelength of 450 nm is 0.025 nm-1 occupies 70% of the entire film thickness or above. When this photo mask blank is used for fabricating a mask for ArF exposure, the film thickness and composition are selected so that the optical density of the light shielding film (12) is within a range from 1.2 to 2.3 for the light having a wavelength of 193 nm or 248 nm.

Description

technical field [0001] The present invention relates to photomasks, photomask blanks as raw materials for photomasks, and methods for their production. Background technique [0002] In recent years, the increase in packing density of large integrated circuits requires miniaturization of circuit patterns, and in order to meet the demand for such miniaturization, advanced semiconductor micromachining technology has become extremely important. For example, the increase in packing density of large integrated circuits essentially requires a technique for thinning wires of wiring patterns in circuits, or a technique for miniaturizing contact hole patterns for interleaving wiring units. This trend toward miniaturization of circuit patterns for large integrated circuits is accelerating because it is the most effective way to increase computing speed and reduce power consumption. [0003] Most of these advanced micromachining techniques are based on photolithography using photomasks...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): G03F1/32G03F1/54C23C14/06G03F1/58G03F1/68H01L21/027
Inventor 吉川博树洼田宽木名濑良纪冈崎智丸山保原口崇岩片政秀福岛祐一佐贺匡
Owner SHIN ETSU CHEM CO LTD