JP2009162851A - Mask, method for manufacturing the same, exposure method and apparatus, and device manufacturing method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a mask for suppressing deformation of a pattern caused by radiation heat of illumination light for exposure. <P>SOLUTION: A transmissive reticle R1 to be irradiated with illumination light IL includes a glass blank 5 transmitting the illumination light IL and provided on one surface with a pattern of shield film 9 of a predetermined transmittance for attenuating the illumination light IL, and a single- or multi-layered reflection film 8 higher in reflectance to the illumination light IL than the shield film 9 formed at least in an area between the shield film 9 and the glass blank 5. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a mask on which a transfer pattern is formed, an exposure technique using the mask, and a device manufacturing technique using the exposure technique.

  In a lithography process for manufacturing a device such as a semiconductor element or a liquid crystal display element (electronic device, microdevice, etc.), a photoresist is applied to a circuit pattern formed on a reticle (or a photomask) via a projection optical system. In order to perform projection exposure on a wafer (or glass plate, etc.), a static exposure type (collective exposure type) projection exposure apparatus such as a stepper, or a scanning projection exposure apparatus (scanning type exposure apparatus) such as a scanning stepper Such an exposure apparatus is used. The reticle used in such an exposure apparatus is usually manufactured by forming a predetermined pattern on a glass blank with a light shielding film such as chromium.

Recently, in addition to shortening the exposure wavelength, optimizing illumination conditions, and increasing the numerical aperture of the projection optical system in accordance with the miniaturization of patterns of semiconductor elements, etc., a phase shifter between the patterns of the light shielding film is used. In order to control the amount of light reduced in the light transmission part in addition to the phase shift reticle (for example, see Patent Document 1) provided with a halftone reticle in which a certain degree of transmittance is imparted to the pattern of the light shielding film, or the light attenuation part It has been proposed to use various reticles such as a reticle (see, for example, Patent Document 2) provided with a reduced light amount control layer.
Japanese Examined Patent Publication No. 62-50811 JP 2006-330635 A

  In a conventional exposure apparatus, for example, when the same reticle pattern is sequentially exposed to a lot of wafers, the irradiation heat of the exposure light is applied to the glass blank through the light-shielding film forming the reticle pattern. There is a possibility that the glass blank gradually expands due to conduction, and the pattern of the reticle is gradually deformed. Although the amount of deformation of the reticle pattern due to such irradiation heat is small, it is preferable to suppress the thermal expansion of such a pattern as much as possible when circuit patterns such as semiconductor elements are further miniaturized in the future.

  In particular, in order to form a finer pattern on the wafer, when performing double patterning in which the reticle pattern is exposed twice on the wafer across the wafer development process, or different exposures on different layers on the same wafer. When exposure is performed by a mix-and-match method using an apparatus, it is necessary to suppress deformation including thermal expansion of a reticle pattern during exposure as much as possible.

  In view of such circumstances, it is an object of the present invention to provide a mask capable of suppressing deformation of a pattern due to exposure heat of exposure light, a manufacturing technique thereof, and an exposure technique and a device manufacturing technique using the mask.

A mask according to the present invention is a transmission type mask that is irradiated with illumination light, and has a flat plate member having a pattern formed by a light-shielding film that transmits the illumination light and attenuates the illumination light on one surface, and And a reflection film that is formed in at least a part of the region between the light shielding film and the flat plate member and has a higher reflectance with respect to the illumination light than the light shielding film.
The method for manufacturing a mask according to the present invention is a method for manufacturing a transmissive mask to which illumination light is irradiated, and a reflective film that reflects the illumination light is formed on one surface of a flat plate member that transmits the illumination light. Forming a light-shielding film that has a lower reflectance to the illumination light than the reflective film and attenuates the illumination light so as to cover the reflective film on one surface of the flat plate member, and the flat plate And patterning the reflective film and the light shielding film formed on the shaped member.

The exposure method according to the present invention includes the steps of illuminating the mask of the present invention with illumination light and exposing the object with illumination light transmitted through the mask.
An exposure apparatus according to the present invention includes a first stage that holds the mask of the present invention, an illumination optical system that illuminates the mask with illumination light, and a second stage that holds an object exposed by the illumination light transmitted through the mask. Are provided.

  According to the present invention, the illumination light is reflected by the reflective film provided in at least a part of the area between the light shielding film of the mask and the flat plate member. Therefore, the irradiation heat of the illumination light (exposure light) is less likely to be transmitted to the flat plate member, so that the deformation of the mask pattern due to the irradiation heat is suppressed.

Hereinafter, an example of a preferred embodiment of the present invention will be described with reference to the drawings.
FIG. 1 shows a schematic configuration of an exposure apparatus EX according to the present embodiment. The exposure apparatus EX is a so-called scanning stepper as a step-and-scan projection exposure apparatus (scanning exposure apparatus). In FIG. 1, an exposure apparatus EX includes an illumination system 20 that illuminates a reticle R1 (mask) using exposure illumination light (exposure light) IL, a reticle stage RST that holds and drives the reticle R1, and a reticle R1. A projection optical system PL for projecting an image of the pattern onto the wafer W, a wafer stage WST for holding and driving the wafer W, a main control system 31 comprising a computer for comprehensively controlling the operation of the entire apparatus, and exposure. A quantity control system 32, a stage control system 33, and other processing systems are provided. In the following description, the Z axis is taken in parallel with the optical axis AX of the projection optical system PL, the Y axis is relative to the reticle and the wafer in a direction perpendicular to the Z axis, and the X axis is perpendicular to the Y axis. A description will be given assuming that the rotation (tilt) directions around the X, Y, and Z axes are the θx, θy, and θz directions, respectively.

  The illumination system 20 includes a light source and an illumination optical system as disclosed in, for example, Japanese Patent Application Laid-Open No. 2001-313250 (corresponding US Patent Application Publication No. 2003/0025890). A part of the light source and the illumination optical system is installed in the main body 14. The illumination optical system includes an illuminance uniformizing optical system including an optical integrator (a fly-eye lens, a rod integrator (internal reflection type integrator), a diffractive optical element, etc.), a reticle blind (these are installed in the main body 14). A mirror 15 that bends the optical path of the illumination light IL downward, and a condenser lens 16.

The illumination system 20 illuminates the slit-shaped illumination region 21R in the pattern region 22 on the pattern surface (lower surface, reticle surface) of the reticle R1 defined by the reticle blind with illumination light IL with a substantially uniform illuminance. In the vicinity of the pattern region 22 of the reticle R1, a pair of alignment marks (reticle marks) 23A and 23B are formed at predetermined intervals in the X direction. As the illumination light IL, for example, ArF excimer laser light (wavelength 193 nm) is used. Illumination light includes KrF excimer laser light (wavelength 247 nm), F ₂ laser light (wavelength 157 nm), harmonic of YAG laser, harmonic of solid-state laser (semiconductor laser, etc.), or emission line of mercury lamp (i-line) Etc.) can also be used.
The exposure control system 32 monitors the amount of illumination light branched in the illumination optical system, and obtains the illuminance (product of pulse energy and frequency) of the illumination light on the wafer W from the monitoring result. Based on this illuminance, the output of the light source and the like are controlled so that the exposure amount for the wafer W becomes the target value set by the main control system 31.

  The mirror 15 and the condenser lens 16 of the illumination system 20 are held on a frame (not shown) via holding members 17 and 18, respectively. The main body 14 is also held by the frame. On the surfaces other than the surfaces of the holding members 17 and 18, the surface of the holding member (not shown) of the optical member in the main body 14, and the surface in contact with the reticle R 1 above the reticle stage RST, the reticle R 1 ( Alternatively, a rough surface of the ground glass surface for diffusing the illumination light IL reflected from (or another reticle) is formed. Further, the rough surface is provided with a black paint or film for absorbing the illumination light IL. This prevents the reflected light of the illumination light IL from the reticle R1 or the like from causing flare in the illumination system 20.

  Under the illumination light IL, the pattern in the illumination area 21R of the reticle R1 is projected onto the wafer W at a projection magnification β (β is, for example, 1/4, 1/5, etc.) via the bilateral telecentric projection optical system PL. Are projected onto an exposure area (not shown) elongated in the non-scanning direction on one shot area. The projection optical system PL of this example is a refractive system, for example, but a catadioptric system or the like can also be used. In this example, the wafer W as an object to be exposed (photosensitive substrate) is a disk-shaped substrate made of a semiconductor such as silicon or SOI (silicon on insulator), and a target layer or the like is formed on this surface as described later. A photoresist (photosensitive material) is applied thereon.

  The reticle R1 is attracted and held on the reticle stage RST, and the reticle stage RST moves on the reticle base 24 at a constant speed in the Y direction. For example, a synchronization error (or pattern image of the reticle R1 and the exposure on the wafer W is being exposed). The reticle R1 is scanned by slightly moving in the X direction, Y direction, and θz direction so as to correct the positional deviation amount with respect to the shot area. The laser interferometers 25X and 25Y measure, for example, at least the position of the reticle stage RST in the X direction and the Y direction with a resolution of about 0.1 nm with reference to the projection optical system PL, and measure the rotation angle in the θz direction. The value is supplied to the stage control system 33 and the main control system 31. The stage control system 33 controls the position and speed of the reticle stage RST via a drive mechanism (such as a linear motor) (not shown) based on the measured value and the control information from the main control system 31.

  Further, since the exposure apparatus EX of this example performs exposure applying the liquid immersion method, the exposure apparatus EX is locally arranged so as to surround an optical element (not shown) on the most image plane side (wafer W side) constituting the projection optical system PL. A nozzle unit 40 constituting a part of the liquid immersion mechanism is provided. At the time of scanning exposure, the liquid LQ that transmits the illumination light IL such as pure water is supplied from the liquid supply device 41 to the flow path in the nozzle unit 40 via the supply pipe 42, and the projection optical system PL, the wafer W, and the like. A local space (local immersion space) surrounding the exposure area is filled with the liquid LQ at a predetermined temperature. Further, the liquid LQ supplied in this way is recovered by the liquid recovery device 43 via the flow path in the nozzle unit 40 and the recovery pipe 44. The liquid supply device 41 and the liquid recovery device 43 are controlled by the main control system 31. In addition, as a local immersion mechanism of this example, the immersion mechanism currently disclosed by the international publication 99/49504 pamphlet or the international publication 2004/053955 pamphlet etc. can also be used, for example.

  In FIG. 1, a wafer W is held on a wafer stage WST via a wafer holder (not shown). The wafer stage WST moves on the wafer base 26 at a constant speed in the Y direction, and steps in the X and Y directions. An XY stage 27 that moves and a Z tilt stage 28 are provided. The Z tilt stage 28 performs focusing and leveling of the wafer W based on a measurement value of the Z position on the surface of the wafer W by an auto focus sensor (not shown). The position of wafer stage WST in the XY plane and the rotation angles in the θx, θy, and θz directions are measured by laser interferometers 29X and 29Y. Based on the measured values and control information from main control system 31, the stage Control system 33 controls the operation of wafer stage WST via a driving mechanism (not shown) (such as a linear motor).

  Further, an off-axis type alignment sensor ALG for measuring an alignment mark (wafer mark) on the wafer W is arranged on the side surface of the projection optical system PL, and the main control system 31 is based on the detection result. The wafer W is aligned. Further, the Z tilt stage 28 has an aerial image measurement system 35 that scans images of the reticle marks 23A and 23B by the projection optical system PL through slits 36 parallel to the Y axis and the X axis, and detects the positions of the images. It is provided. Based on the detection result of the aerial image measurement system 35, the main control system 31 can perform alignment of the reticle R1. In this case, the positional relationship (baseline) between the centers of the images of the reticle marks 23A and 23B and the detection center of the alignment sensor ALG can be obtained using a reference mark (not shown) on the Z tilt stage 28.

  At the time of exposure, step movement that moves wafer stage WST in the X and Y directions to move a shot area to be exposed next on wafer W to the front of the exposure area and scanning exposure are repeated. At the time of scanning exposure, the projection magnification of the reticle stage RST and wafer stage WST in the scanning direction SD (Y direction) while supplying the liquid LQ between the projection optical system PL and the wafer W by the local liquid immersion mechanism including the nozzle unit 40. Driving with β as the speed ratio, the reticle R1 and one shot region on the wafer W are synchronously scanned in a state where the illumination light IL is irradiated. In this way, an image of the pattern of the reticle R1 by the projection optical system PL is exposed to each shot area on the wafer W by the step-and-scan method.

Next, an example of an operation for forming a pattern for a predetermined device on the wafer W by the double process method using the exposure apparatus EX of the present embodiment will be described.
In this case, it is assumed that several layers of circuit patterns have already been formed in a plurality of shot regions on the wafer W by the device manufacturing process so far, and wafer marks for alignment have also been formed. The device to be manufactured in this embodiment is a flash memory as an example, and the pattern formation process described below is applied when forming an element isolation gate contact metal which is the finest pattern in the device as an example. It can be done.

Specifically, the circuit pattern formed in each shot region of the wafer W has a period (pitch) P in the X direction and a width of the protrusion P / 2 as shown in the partial enlarged view of FIG. A line-and-space pattern (hereinafter referred to as an L & S pattern) in which the ratio of the width in the X direction between the convex portion and the concave portion (duty ratio) is 1: 1.
2A is an enlarged view showing a part of the pattern formed in the pattern region 22 of the reticle R1 in FIG. 1, and FIG. 2B is a cross-sectional view taken along line BB in FIG. 2A. is there. As shown in FIG. 2A, an L & S pattern 6 in which line patterns 7 having a width Pr in the X direction are arranged in the X direction with a period of 2Pr is formed on the reticle R1. In this case, using the projection magnification β of the projection optical system PL, there is a relationship of Pr = P / β with respect to the period P of the L & S pattern on the wafer W in FIG.

  That is, the period (β · 2Pr) of the image of the line pattern 7 of the L & S pattern 6 on the reticle R1 by the projection optical system PL is twice the period P of the L & S pattern finally formed on the wafer W. The period 2Pr (line width Pr) of the L & S pattern 6 on the reticle R1 is a value close to the resolution limit of the projection optical system PL, for example, and the period P (line width P / 2) of the L & S pattern on the wafer W is The value exceeds the resolution limit of the projection optical system PL. For example, the line width P / 2 is 32 to 64 nm, and the value obtained by converting the line width Pr of the L & S pattern 6 on the reticle R1 into the line width of the image on the wafer W (= β · Pr = P) is 64 to 128 nm. It is.

In FIG. 2B, a reticle R1 has a line pattern 7 on a lower surface 5a of a rectangular flat glass blank 5 made of quartz (SiO ₂ ) or fluorite (CaF ₂ ) that transmits the illumination light IL. Is formed in the X direction with a period of 2Pr. Further, each line pattern 7 includes a reflection film 8 that is formed on the lower surface 5a of the glass blank 5 and reflects the illumination light IL, and a light shielding film 9 that is formed so as to cover the reflection film 8 and attenuates the illumination light IL. It is configured.

The reflective film 8 has a higher reflectance with respect to the illumination light IL than the light shielding film 9, and the reflectance of the illumination light IL in the reflective film 8 is 60% or more. The transmittance of the illumination light IL in the light shielding film 9 is approximately 0%. The light shielding film 9 is, for example, a chromium (Cr) single-layer film or a multi-layer film. On the other hand, the reflective film 8 includes, as an example, an aluminum (Al) layer 8a, 8d, 8g, a silicon oxide (SiO ₂ ) layer 8b, 8e, and a molybdenum (Mo) layer as shown in FIG. It is a film having a seven-layer structure in which 8c and 8f are alternately stacked.

  Since each line pattern 7 of the L & S pattern 6 of the reticle R1 of the present embodiment has a reflective film 8 between the light shielding film 9 and the glass blank 5, the illumination light IL irradiated from the upper surface to the reticle R1. Among them, most of the light beam shielded by the light shielding film 9 is reflected by the reflective film 8 and travels toward the upper part of the reticle R1. Therefore, the proportion of the irradiation heat of the illumination light IL that is conducted to the glass blank 5 through the light shielding film 9 is extremely small, and the deformation amount of the L & S pattern 6 due to the irradiation heat of the illumination light IL is extremely small.

  In this embodiment, as will be described later, a reticle R2 formed with an L & S pattern whose phase is 180 ° different from that of the L & S pattern 6 in FIG. 2A is used. In each line pattern, a reflective film 8 is formed between the light shielding film 9 and the glass blank 5. Therefore, even when the reticle R2 is used, the deformation amount of the L & S pattern due to the irradiation heat of the illumination light IL is extremely small.

  Hereinafter, the circuit pattern forming process of the present embodiment will be described with reference to the flowchart of FIG. 4 and FIGS. 3A to 3G which are enlarged sectional views of a part of one shot area on the wafer W. explain. The following circuit pattern formation process is sequentially performed on one lot of wafers. Hereinafter, a case where a circuit pattern is formed on the wafer W of FIG.

  First, in step 101 of FIG. 4, as shown in FIG. 3B, a target layer 51 made of an interlayer insulating film such as an organic polymer is formed on the wafer W, and a silicon oxide film or silicon is formed thereon. A hard mask layer 52 made of a ceramic such as a nitride film and having different reactivity to etching with both the target layer 51 and the photoresist is formed. Further, a positive photoresist 53 is applied on the hard mask layer 52 of the wafer W by a coater / developer (not shown). Note that the present invention can also be applied when the target layer 51 is a metal film. Further, instead of using the hard mask layer 52, it is possible to use a bilayer (two-layer) resist.

  Thereafter, the wafer W is transferred to the exposure apparatus EX shown in FIG. Then, in step 102, the reticle R1 is loaded onto the reticle stage RST of the exposure apparatus EX in FIG. 1, and the reticle R1 is aligned using the aerial image measurement system 35. Next, in steps 103 to 105, the wafer W coated with the photoresist in step 101 is loaded onto the exposure apparatus EX, and an image of a pattern including the L & S pattern 6 of FIG. Exposure. That is, in step 103, the wafer W is loaded onto the wafer stage WST of the exposure apparatus EX, and in step 104, the alignment of the wafer W is performed using the alignment sensor ALG. In the next step 105, an image of the pattern of the reticle R1 is exposed to each shot area of the wafer W using the exposure apparatus EX by the liquid immersion method and the scanning exposure method. As a result, each shot area on the wafer W is exposed to an image of the L & S pattern 6 of the reticle R1 (that is, an image of the L & S pattern having the pitch 2P in FIG. 3A). However, the exposure amount at this time is set so that the width of the exposure amount distribution E (X) across the sensitivity Eth of the photoresist 53 on the wafer W becomes P / 2 as shown in FIG. It is set so that substantially the same result as that obtained by exposing an image of an L & S pattern having a ratio of line width to space width of 1: 3 is obtained.

Thereafter, the wafer W exposed in step 105 is transferred to a coater / developer (not shown) in step 106 to develop the photoresist 53 on the wafer W. As a result, a resist pattern in which resist portions 53A having a width P / 2 are arranged in the X direction at a pitch 2P is obtained on the wafer W as shown in FIG.
Next, the wafer W is transferred to an etching apparatus (not shown), and as shown in FIG. 3C, following the heating (curing), the hard mask layer 52 is etched using the resist portion 53A as a mask, and the resist is resisted. The portion 53A is peeled off to form a hard mask portion 52A having a period 2P shown in FIG.

  In the next step 107, a coater / developer (not shown) applies a positive photoresist 53D onto the wafer W as indicated by a two-dot chain line, and then the wafer W is transferred to the exposure apparatus EX shown in FIG. In the next step 108, the reticle R2 is loaded onto the reticle stage RST of the exposure apparatus EX, and alignment of the reticle R2 is performed using the aerial image measurement system 35. On the reticle R2, there is formed an L & S pattern which is the same as the L & S pattern 6 on the reticle R1 in FIG. 2A and whose position in the X direction is different by Pr (180 ° in phase).

  In the next step 109, the wafer W coated with the photoresist in step 107 is loaded onto the wafer stage WST of the exposure apparatus EX, and the reticle R2 is loaded on each shot area on the wafer W in the same manner as in steps 103 to 105. Expose the pattern image. In this case, the position of wafer W on wafer stage WST is the same as that in FIG. 3B, whereas the exposure amount distribution E (X) of the pattern image of reticle R2 is shown in FIG. As shown, the phase is 180 ° different from the state of FIG. The exposure amount at this time is also set so that the width of the exposure amount distribution E (X) across the sensitivity Eth of the photoresist 53D on the wafer W becomes P / 2.

  In the next step 110, the wafer W exposed in step 109 is transferred to a coater / developer (not shown), and the photoresist 53D of the wafer W is developed. As a result, as shown in FIG. 3F, a resist pattern in which resist portions 53B having a width P / 2 are arranged in the X direction at a pitch 2P is disposed between the plurality of hard mask portions 52A on the wafer W. A mask layer 54 having a shape is obtained. Thereafter, in an etching apparatus (not shown), the wafer W is heated (cured), the target layer 51 is etched using the mask layer 54 of the wafer W as a mask, and then the hard mask portion 52A and the resist portion 53B are peeled off. . As a result, as shown in FIG. 3G, an L & S pattern with a duty ratio of 1: 1 is formed on the wafer W by arranging the target portions 51A having the width P / 2 in the X direction with the period P.

In the next step 111, resist coating, exposure, development, and substrate processing (heating (curing), etching, etc.) are repeated a predetermined number of times on the wafer W, and then a device assembly step (dicing process, bonding process, packaging process). Semiconductor devices are manufactured through an inspection step and the like.
In the above-described pattern forming operation of the double process method, the reticles R1 and R2 each have a high reflectance of the illumination light IL, and the thermal deformation of the patterns of the reticles R1 and R2 due to the irradiation heat of the illumination light IL is extremely small. Therefore, the position of the pattern of the reticle R1 and the image of the reticle R2 can be accurately set so that the phase is 180 ° different between the two exposures, so that the pattern has a pitch P and a duty ratio of 1: 1. Can be accurately formed on the wafer. In other words, a fine pattern exceeding the resolution limit of the exposure apparatus can be formed with high accuracy.

  Further, since the illumination light IL reflected from the reticles R1 and R2 is absorbed by the black paint or coating on the surfaces (rough surfaces) such as the holding members 17 and 18 and the reticle stage RST, flare occurs in the illumination system 20. There is nothing. Further, since the holding members 17 and 18 are supported by a frame (not shown) and have a large heat capacity, the amount of deformation of the holding members 17 and 18 due to the reflected light is negligible.

  Next, an example of a method for manufacturing the reticle R1 will be described with reference to the partially enlarged views of FIGS. First, as shown in FIG. 5A, a reflective film 8R is formed on one surface of the glass blank 5 (a surface corresponding to the lower surface 5a in FIG. 2B) by vapor deposition or the like. Next, as shown in FIG. 5B, a light shielding film 9R is formed on the reflective film 8R by vapor deposition or the like. Next, as shown in FIG. 5C, after applying a resist PR onto the light shielding film 9R, an L & S pattern with a period of 2Pr in FIG. A pattern corresponding to 6 is formed. Thereafter, the resist PR is developed, and then a series of processes (patterning) in which etching is performed, whereby a line pattern 7 made of a reflective film 8 and a light shielding film 9 is formed on the glass blank 5 as shown in FIG. Are arranged in a period of 2Pr. In this way, the reticle R1 can be easily manufactured.

Effects and modifications of the above embodiment are as follows.
(1) The reticle R1 of the above embodiment is a transmissive reticle that is irradiated with the illumination light IL. The reticle R1 transmits the illumination light IL, and the L & S pattern is formed on the lower surface 5a by the light shielding film 9 that attenuates the illumination light IL. Are formed between the light shielding film 9 and the glass blank 5 and have a reflection film 8 having a higher reflectance with respect to the illumination light IL than the light shielding film 9.

According to this reticle R1, since the illumination light IL is reflected by the reflective film 8, the irradiation heat of the illumination light IL is hardly conducted to the glass blank 5, and the deformation of the pattern of the reticle R1 due to the irradiation heat is suppressed. .
In FIG. 2B, the reflective film 8 is provided on the entire surface of the light shielding film 9, but the reflective film 8 may be provided between at least a part of the light shielding film 9 and the glass blank 5.

(2) Moreover, since the reflection film 8 is a multi-layer film 8a to 8g, high reflection characteristics can be obtained. Further, since the reflection film 8 includes the metal films (8a, 8c) and the oxide film (8b), it can be easily formed. The reflective film 8 may be formed from a single layer film.
Moreover, since the reflectance of the reflective film 8 is 60% or more, the influence of the irradiation heat of the illumination light IL can be sufficiently reduced.

The reflectance of the reflective film 8 may be smaller than 60% under the condition that it should be larger than the reflectance of the light shielding film 9.
(3) Moreover, since the light shielding film 9 is a metal single layer or a plurality of layers, it can be easily formed. However, as the light shielding film 9, an arbitrary film having a high attenuation effect of the illumination light IL can be used.
Further, the transmittance of the light shielding film 9 of the above embodiment is approximately 0%.

However, when the reticle R1 is, for example, a halftone reticle, the overall transmittance of the reflective film 8 and the light shielding film 9 of the line pattern 7 (this is regarded as the transmittance of the light shielding film 9) is 0 to 10. %, For example, about 6%.
Thus, a halftone reticle can be obtained and thermal deformation of the reticle pattern can be suppressed.

Furthermore, the mask of the present invention can also be applied to a phase shift reticle. Furthermore, the present invention can also be applied when the reticle pattern is an isolated pattern.
(4) In addition, the reticle manufacturing method shown in FIGS. 5A to 5D of the above embodiment is a method for manufacturing a transmissive reticle R1 irradiated with illumination light, and transmits the illumination light. The step of forming the reflective film 8R that reflects the illumination light on one surface of the glass blank 5 (FIG. 5A) and the one surface of the glass blank 5 that is illuminated more than the reflective film 8R so as to cover the reflective film 8R A step of forming a light-shielding film 9R that attenuates illumination light while having a low reflectance to light (FIG. 5B), and a step of patterning the reflective film 8R and the light-shielding film 9R formed on the glass blank 5 (FIG. 5) (C) and (D)).

Therefore, the reticle R1 can be easily manufactured by a lithography process.
(5) Further, the exposure method of the exposure apparatus EX of the above embodiment includes the step 105 of illuminating the reticle R1 with the illumination light IL and exposing the wafer W (object) with the illumination light IL transmitted through the reticle R1. In addition, the exposure apparatus EX of the above embodiment includes a reticle stage RST that holds the reticle R1, an illumination optical system that illuminates the reticle R1 with the illumination light IL (a part of the illumination system 20), and illumination that passes through the reticle R1. And a wafer stage WST that holds the wafer W exposed by the light IL.

In the present embodiment, since the thermal deformation of the pattern of the reticle R1 is small, the image of the pattern of the reticle R1 can be transferred onto the wafer W with high accuracy.
(6) In this case, a rough surface and a coating (coating) that diffuses and absorbs the illumination light IL reflected from the reflective film of the reticle R1 on the holding members 17, 1 and the like such as the reticle stage RST and the mirror 15 (antireflection part) Step 105 includes a step of diffusing and absorbing the illumination light IL reflected from the reflective film of the reticle R1. Accordingly, the occurrence of flare in the illumination system 20 can be prevented. Note that only the diffusion or absorption of the illumination light IL may be performed.

Note that the holding members 17 and 18 and the like may only diffuse or absorb the illumination light IL.
(7) Further, in the exposure method, the wafer W exposed with the illumination light IL is developed 106, the reticle R2 is illuminated with the illumination light IL, and the wafer W is exposed with the illumination light IL transmitted through the reticle R2. Step 109 is included. In this case, a fine pattern exceeding the resolution limit of the exposure apparatus EX can be formed on the wafer W by the double process method. In addition, since the reticle R2 also has little pattern deformation due to irradiation heat, the fine pattern can be formed with high accuracy.

  (8) In the above embodiment, the reticle R1 may be used as the reticle R2. In this case, the positional relationship between the reticle R1 and the wafer W when the wafer W is exposed through the reticle R1 for the second time is the same as the positional relationship when the wafer W is exposed through the reticle R1 for the first time. Thus, it is necessary to make the difference by the line width Pr (180 ° in phase) of the L & S pattern 6.

(9) In the device manufacturing method of the above embodiment, the steps 105 and 109 for exposing the wafer W using the exposure method or the exposure apparatus EX of the above embodiment and the step 106 for processing the exposed wafer W are performed. , 110.
According to this manufacturing method, the pattern of the reticle can be formed on the wafer W with high accuracy, so that the semiconductor device can be manufactured with high accuracy.

In the above embodiment, the exposure amount is controlled with respect to the threshold value to form a pattern with a duty ratio of 1: 3 in FIG. 3B. For example, this is disclosed in Japanese Patent Application Laid-Open No. 2007-31508. As described, a pattern having a duty ratio of 1: 3 may be formed by combining a lithography process and a resist slimming process.
Of course, the present invention can also be applied to a process in which exposure is performed at a normal time without using a double process.

The present invention can also be applied to the case where exposure is performed by a mix-and-match method.
Furthermore, the present invention can be applied not only to a scanning exposure type projection exposure apparatus but also to exposure using a batch exposure type (stepper type) projection exposure apparatus. The present invention can also be applied to the case where exposure is performed with a dry exposure apparatus.
Further, as disclosed in, for example, Japanese translations of PCT publication No. 2004-51850 (and corresponding US Pat. No. 6,611,316), two reticle patterns are synthesized on a substrate via a projection optical system. The present invention can also be applied to an exposure apparatus that performs double exposure of one shot area on a substrate almost simultaneously by one scanning exposure.

  In addition, the present invention is not limited to application to a semiconductor device manufacturing process. For example, a manufacturing process of a display device such as a liquid crystal display element or a plasma display formed on a square glass plate, or an imaging element (CCD, etc.), micromachines, MEMS (Microelectromechanical Systems), thin film magnetic heads, and various devices such as DNA chips can be widely applied to the manufacturing process. Furthermore, the present invention can also be applied to a manufacturing process when manufacturing a mask (photomask, reticle, etc.) on which mask patterns of various devices are formed using a photolithography process.

  As described above, the present invention is not limited to the above-described embodiment, and it is needless to say that various configurations can be taken without departing from the gist of the present invention.

It is a perspective view which shows schematic structure of the exposure apparatus used in an example of embodiment of this invention. (A) is an enlarged plan view showing a part of the pattern of reticle R1 in FIG. 1, (B) is a sectional view taken along line BB in FIG. 2 (A), and (C) is a line pattern in FIG. 2 (B). 7 is an enlarged view of FIG. In the circuit pattern formation process of embodiment of this invention, it is an expanded sectional view which shows the exposure amount distribution of the projection image on a wafer, and the change of the pattern formed on a wafer. It is a flowchart which shows the circuit pattern formation process of embodiment of this invention. It is a partial enlarged view which shows an example of the manufacturing process of reticle R1 of FIG.

Explanation of symbols

  5 ... Glass blank, 6 ... L & S pattern, 7 ... Line pattern, 8 ... Reflection film, 9 ... Light shielding film, 17, 18 ... Holding member, 20 ... Illumination system, R1, R2 ... Reticle, PL ... Projection optical system, W ... wafer, 51 ... target layer, 52 ... hard mask layer, 53, 53D ... photoresist, 54 ... mask layer

Claims (16)

A transmissive mask irradiated with illumination light,
A plate-like member having a pattern formed by a light-shielding film that transmits the illumination light and attenuates the illumination light on one surface;
A reflection film that is formed in at least a part of the area between the light shielding film and the flat plate member and has a greater reflectance to the illumination light than the light shielding film;
A mask characterized by comprising:   The mask according to claim 1, wherein the reflective film is a multilayer film.   The mask according to claim 2, wherein the reflective film includes a metal film and an oxide film.   The mask according to any one of claims 1 to 3, wherein the reflectance of the reflective film is 60% or more.   The mask according to claim 1, wherein the light shielding film is a metal single layer or a multilayer film.   6. The mask according to claim 1, wherein the light-shielding film has a transmittance of 0 to 10%. A method of manufacturing a transmission type mask irradiated with illumination light,
Forming a reflective film that reflects the illumination light on one surface of the flat member that transmits the illumination light;
Forming a light-shielding film on the one surface of the flat plate member that has a lower reflectance to the illumination light than the reflective film and attenuates the illumination light so as to cover the reflective film;
Patterning the reflective film and the light shielding film formed on the flat plate member;
A method for manufacturing a mask, comprising:   An exposure method comprising: illuminating the first mask according to any one of claims 1 to 6 with illumination light, and exposing the object with the illumination light transmitted through the first mask. .   9. The exposure method according to claim 8, further comprising a step of performing at least one of diffusion and absorption of the illumination light reflected from the reflective film of the first mask. Developing the object exposed with the illumination light;
Illuminating the second mask according to any one of claims 1 to 6 with the illumination light, and exposing the object with the illumination light transmitted through the second mask;
The exposure method according to claim 8 or 9, wherein The first mask and the second mask are the same;
The positional relationship between the second mask and the object when the object is exposed through the second mask is different from the positional relationship when the object is exposed through the first mask. The exposure method according to claim 10, wherein: Exposing the photosensitive substrate using the exposure method according to any one of claims 8 to 11,
Processing the exposed photosensitive substrate. A first stage for holding the mask according to any one of claims 1 to 6;
An illumination optical system for illuminating the mask with illumination light;
A second stage for holding an object exposed by the illumination light transmitted through the mask;
An exposure apparatus comprising:   The antireflection part that performs at least one of diffusion and absorption of the illumination light reflected from the reflective film of the mask is provided in at least a part of the first stage and the illumination optical system. Item 14. The exposure apparatus according to Item 13.   The exposure apparatus according to claim 14, wherein the antireflection portion includes a member having a film that absorbs the illumination light on a rough surface. Exposing the photosensitive substrate using the exposure apparatus according to any one of claims 13 to 15,
Processing the exposed photosensitive substrate.

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