TWI303456B - - Google Patents

Description

1303456__ V. INSTRUCTION DESCRIPTION (1) ^^ Field of the Invention: The present invention relates to a method for changing the transmittance of a semiconductor photomask, in particular to an attenuated phase shift in a high transmittance (transmi ttance) attenuation phase shift mask (attenuated phase shift) Mask: APSM) Photoresist coating background: Integral circuit (IC) has been significantly improved in technology, and with the light, thin, short and small requirements of electronic products, increasing the density of electronic components has become a kind of trend. By reducing the size of the electronic components, the integration density of the semiconductor & With the shrinking of the size of electronic components, many new challenges have arisen in the manufacturing process of the body circuit. For example, although the size of the random memory (DRAM) unit is reduced, the storage capacity is reduced and the components are reliable. Deficiency in re li ability. In lithography, the size of electronic components on semiconductor wafers is shrinking and lithography. = The role played is also important. In the integrated circuit, the lithography system ^% shells a complete copy (C〇py) of the pattern on the reticle onto the wafer, and the same negative must have an accurate alignment between multiple layers (a 1丨gnment), And whether the multiple layers are precisely aligned, often determines the formation of metal interconnects. Long-term performance

1303456 V. DESCRIPTION OF THE INVENTION (2) ~ ^ 'The lithography contains a photoresist pattern formed as a mask to form a desired structure such as a contact window 'metal interconnect and a semiconductor element, so the photoresist coating is good. Bad will also affect the process results. This photoresist pattern is patterned on a film layer and aligned to its bottom layer. & The construction of semiconductor components with very fine patterns requires a lithography process with ultra-sub micrometer resolution. In semiconductor lithography, the main key to limiting resolution is the numerical aperture (NA) of the lens used in the optical system and the wavelength (λ) of the source. A larger ΝΑ provides a better resolution for a particular wavelength. However, in order to obtain this advantage, it also pays a great price. That is, as να increases, the depth of the focal length (depth of f〇cus: D0F) is significantly reduced. In addition, other methods can be used to enhance the resolution of the resist pattern, such as a device using off-axis exposure (0 A I ) in an exposure machine, or a phase shift mask for resist pattern transfer. The principle that the phase shifting reticle can make the resolution of the south is that after the light passes through the reticle, different phase changes are generated, and the constructive or destructive interference between the different phases is utilized to make the light resisting band ( Energy band) is sharper and improves resolution. Therefore, as the size of electronic components is reduced, the use of phase shift masks to enhance the resolution of photoresist patterns is becoming more common. In the process of manufacturing the reticle, there is a step that cannot be lacked, that is, the inspection of defects, and the inspection of defects is done after the reticle is manufactured.

Page 6 1303456 V. Description of invention (3) After the completion of the reticle to the reticle inspection machine (inSpecti〇n t〇〇i). The mask inspection machine performs the defect inspection in the contrast mode, so the black area and the white area on the mask are very clear, the black area is completely opaque and the white area is completely transparent. section. That is to say, the beta-like reticle inspection machine is based on gray scales as a contrast, and is divided into 256 levels with extremely black and ultra-white, and uses this level of color to capture the lack of the mask. Therefore, a mask is sent. When the reticle inspection machine is used to perform the reticle defect inspection, the sensitivity of the machine to the defect ("...^" "is very important. The material of the binary mask is generally quartz plus chrome. (Cr), its light transmittance is 〇 and 1〇〇% respectively, that is to say, the f-light condition of the binary mask is only the difference between extremely black and very white, which is to capture the reticle inspection machine. The defect of the mask itself is relatively easy. In addition, the phase shift mask comprises a transparent substrate and a phase shift layer, wherein the transparent substrate is generally composed of quartz material, and the phase shift layer may comprise M〇Si〇N or M. 〇Si〇 or CrF 'Because they are all light-transmissive, the light transmittance of the phase shift layer is very important for the reticle inspection machine with gray scale as the contrast of light and dark. Therefore, for a reticle inspection machine with a wavelength of 3 6 5 angstroms, if the phase shift layer is transparent When the rate is very high (for example, more than 45%) and the contrast with the brightness of quartz is insufficient, it will affect the gray scale distribution made by the reticle inspection machine', and the reticle inspection machine will over-capture the reticle defect. Sensitive and detected many false defects (fa 1 sedefect ).

1303456 V. INSTRUCTIONS (4) Attenuation phase shift mask is a commonly used phase shift mask whose phase change is usually 0 degrees and 180 degrees. At present, for the reticle inspection machine with a light source wavelength of 3 6 50 Å, it is difficult to test the phase shifting reticle with a phase shift layer transmittance of more than 4 5%, and the only way to verify it is to reduce the reticle. Check the sensitivity of the machine, but this type of inspection is very likely to lose some of the important defects on the mask, and has a very serious impact on the wafer. Accordingly, the present invention provides a method of reducing the surface transmittance of a phase shifting layer of an attenuated phase shifting mask to improve contrast between light and dark and to enhance the inspection capability of a high transmittance attenuating phase shifting mask. __ OBJECTS AND SUMMARY: The object of the present invention is to provide a photoresist coating applied to a high transmittance attenuating phase shift mask inspection to reduce the transmittance of the attenuated phase shift mask to facilitate high transmittance. Attenuation of the phase shift mask inspection. The present invention is a photoresist coating applied to a high transmittance attenuating phase shift mask inspection, comprising: first, providing an attenuating phase shift mask, and then applying a photoresist to the attenuating phase shift mask, Then, the phase shift layer and the photoresist layer of the attenuated phase shifting light 4 are exposed, and finally, the photoresist layer is developed to remove the photoresist on the transparent substrate, leaving the photoresist on the phase shift layer. In this way, the light transmittance of the attenuated phase shift mask can be reduced to facilitate the inspection of the high transmittance attenuating phase shift mask.

Page 8 1303456 V. Description of the invention (5) Contains a transparent substrate and a phase shift layer. Wherein the phase shifting layer may comprise MoSiON or the attenuating phase shifting reticle of the present invention. The transparent substrate may comprise quartz, 〇 〇 S i 〇 or cr F 〇 detailed description of the invention: s a description of the semiconductor light The method of mask transmittance, in particular, is applied to the photoresist coating of the south transmittance reduction phase shift mask inspection. The purpose of the present invention is to provide a method for reducing the surface transmittance of a phase shift layer of an attenuated phase shift mask by applying a layer of removable photoresist on the phase shift layer to reduce the transmittance of the phase shift layer surface. And improve the contrast between light and dark, and improve the inspection ability of the high transmittance attenuation phase shift mask. The details of the following invention can be described in detail with reference to the drawings, and the photoresist coating of the present invention for the light transmittance subtractive phase shift mask inspection is depicted. Figure 1 is a cross-sectional view of an attenuated phase shift mask of the present invention. The attenuating phase shifting reticle comprises a transparent substrate 1 〇〇 and a phase shifting layer 2 〇〇, and the transparent substrate i 组成 is composed of a substance completely transparent. The phase shifting layer 200 is a light having a certain light transmittance. The composition of j. The material of the transparent substrate 100 may be quartz, and the material of the phase shift layer 200 may be MoSiON, MoSiO, or CrF. The phase change of incident light between the phase shifting layer 200 and the fully transparent region 250 is determined by the mode thickness of the phase shift layer 2 〇 。. Attenuating the phase shift mask is to use the transmittance of the phase shift layer 200

1303456 V. Description of the invention (6) Phase change and complete light transmission zone 250. 2 is a cross-sectional view of a photoresist coated on an attenuated phase shift mask of the present invention. & The photoresist is coated on the attenuating phase shift mask, and after the coating is completed, the photoresist layer 300 is formed on the attenuating phase shift mask. The above-mentioned photoresist does not react with the light source of the reticle inspection machine. The light source of the attenuating phase shift mask & inspection station is, for example, light having a wavelength of 3 6 5 Å. i Figure 3 is a schematic diagram of the phase shifting layer and photoresist exposure of the attenuated phase shifting mask of the present invention. Thereafter, the phase shift layer 200 and the photoresist 3 0 0 on the attenuated phase shift mask are exposed, and the exposure is entered from the transparent substrate of the attenuated phase shift mask, that is, the exposure direction. 4 0 0 points to the bottom of the transparent substrate 1 〇〇. The exposure light source cannot penetrate the phase shift layer 200, and the exposure light source is sufficiently sensitive to the photoresist, that is, the photoresist reacts with the exposure light source. Figure 4 is a cross-sectional view showing the phase shifting layer and photoresist development of the attenuated phase shifting mask of the present invention. Then, the photoresist layer 300 is developed, and the photoresist on the transparent substrate 100 is removed after the development is completed, leaving only the photoresist on the phase shift layer 2, that is, after the development is completed. A photoresist layer 3 5 形成 is formed on the phase shift layer 200. Thus, the 'phase shift layer 20 〇 plus the photoresist layer 305 forms a combined layer 5 〇〇, the group of human layers 500 can reduce the transmittance, and increase the brightness of the phase shift mask. : The method 'we can perform' - a strict attenuation phase shift: a good mask quality. Dry up

1303456 V. INSTRUCTION DESCRIPTION (7) The present invention forms a photoresist layer 305 through the phase shift layer 2000 so that the contrast of the attenuated phase shift mask can be similar to a binary mask. Therefore, the present invention can solve the problem that the transmittance of the phase shift layer 200 is high (for example, more than 45%) and the contrast between the light and the darkness of the transparent substrate 100 is insufficient to enable the reticle inspection machine to capture the reticle defect capability. Insufficient situation. The present invention has been described with reference to a preferred embodiment, and is not intended to limit the scope of the invention. Modifications and similar arrangements made without departing from the spirit and scope of the invention are intended to be included within the scope of the appended claims. The scope of the invention should be accorded to the broadest interpretation of all modifications and similar structures. Therefore, the above-described preferred embodiments of the present invention can be used to identify various modifications made without departing from the spirit and scope of the invention.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a cross-sectional view of an attenuated phase shift mask of the present invention. 2 is a cross-sectional view of a photoresist coated on an attenuated phase shift mask of the present invention. FIG. 3 is a schematic diagram of the phase shifting layer and photoresist exposure of the phase shifting mask of the present invention. Figure 4 is a cross-sectional view showing the phase shifting layer and photoresist development of the attenuated phase shifting mask of the present invention. Symbol comparison table: Transparent substrate 1 0 0 Phase shift layer 200 Complete light transmission area 250 Photoresist layer 300, 350 Exposure direction 4 0 0 Combination layer 500

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Claims (1)

1303456 VI. Patent Application No. 1 · A photoresist coating method applied to high transmittance attenuating phase shift mask inspection, the method comprising at least the following steps: providing an attenuated phase shift mask, wherein the attenuated phase shifting light The cover comprises a transparent substrate and a phase shifting layer; coating a photoresist on the attenuating phase shifting mask to form a photoresist layer on the attenuating phase shifting mask; and a phase shifting layer for the attenuating phase shifting mask Exposing with the photoresist layer, the exposure is from the transparent substrate of the attenuating phase shift mask, and the exposed light source is incapable of penetrating the phase shift layer, and the exposed light source is sensitive to the photoresist; and performing the photoresist layer After development and development, the light on the transparent substrate is removed, leaving only the photoresist on the phase shift layer. 2. A photoresist coating method for high transmittance attenuation phase shift mask inspection as claimed in claim 1 wherein the transparent substrate comprises quartz. 3. A photoresist coating method for high transmittance attenuation phase shift mask inspection as claimed in claim 1 wherein the phase shift layer comprises MoSiON. 4. A photoresist coating method for high transmittance attenuating phase shift mask inspection according to claim 1 of the patent application, wherein the phase shift layer comprises Μ 〇 S i 0. 〇 5. A photoresist coating method for high transmittance attenuation phase shift mask inspection as claimed in claim 1 wherein the phase shift layer comprises CrF. Page 13 1303456 VI. Patent Application Range 6. The photoresist coating method for high transmittance attenuation phase shift mask inspection according to item 1 of the patent application scope, wherein the light source is attenuated by the phase shifting mask inspection machine Can't react. 7. A photoresist coating method for high transmittance attenuation phase shift mask inspection according to claim 6 of the patent application, wherein the source of the attenuated phase shift mask inspection machine comprises a wavelength of 3 6 50 angstroms. 8. A photoresist coating structure for attenuating a phase shift mask, the structure comprising: a transparent substrate; a phase shift layer on the transparent substrate, wherein the phase shift layer may be selected from MoSiON, MoSiO, or CrF; and a photoresist A pattern is disposed on the phase shift layer, and the photoresist pattern is consistent with the phase shift layer pattern. 9. The photoresist coating structure of an attenuated phase shifting reticle of claim 8 wherein said transparent substrate comprises quartz. a photoresist coating structure for attenuating a phase shift mask, the structure comprising: a transparent substrate; a phase shift layer on the transparent substrate, wherein a transmittance of the phase shift layer is greater than 45 %; and light a resist pattern on the phase shift layer, the photoresist pattern being consistent with the phase shift layer pattern Page 14 1303456 VI. Designated representative map