Pellicle frame and pellicle

Abstract

The present invention is to provide a pellicle frame in a frame shape, having an upper end face to arrange a pellicle film thereon and a lower end face to face a photomask, and which is characterized by being provided with a notched part from an outer side face toward an inner side face of the upper end face, and to provide a pellicle characterized by including the pellicle frame as a component.

Claims

1. A pellicle comprising: a pellicle frame having a frame shape, an upper end face and a lower end face to face a photomask; and a pellicle film arranged at the upper end face of the pellicle frame, wherein the pellicle frame is provided with at least one recessed portion from an outer side face toward an inner side face of the upper end face, and wherein the recessed portion is a ventilation part.

2. The pellicle according to claim 1, wherein the recessed portion is formed from the outer side face up to the inner side face.

3. The pellicle according to claim 1, wherein the pellicle frame has a thickness of less than 2.5 mm.

4. The pellicle according to claim 1, wherein an adhesive agent or a pressure-sensitive adhesive is provided on the upper end face of the pellicle frame excluding the recessed portion in the upper end face of the pellicle frame.

5. The pellicle according to claim 1, wherein a curved part is not formed in a ventilation passage of the ventilation part.

6. The pellicle according to claim 1, wherein the pellicle is applied to EUV.

7. An assembly comprising the pellicle of claim 1 and an exposure original plate, wherein the pellicle is attached to the exposure original plate.

8. An exposure method, comprising performing an exposure using the assembly according to claim 1.

9. A manufacturing method of a semiconductor device, comprising a step of forming a pattern by irradiating a semiconductor wafer with light wherein the assembly according to claim 7 is adopted.

10. The pellicle according to claim 1, wherein the pellicle film is arranged on the upper end face of the pellicle frame.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) FIG. 1 is a perspective view showing an example of the pellicle frame according to the present invention;

(2) FIGS. 2A and 2B show another example of the pellicle frame according to the present invention, FIG. 2A is a plan view as viewed from the upper end face side, and FIG. 2B is a plan view as viewed from the outer face side of the short side; and

(3) FIG. 3 is a schematic view showing a state that the pellicle according to the present invention is attached onto a photomask.

DESCRIPTION OF THE PREFERRED EMBODIMENT

(4) The pellicle frame according to the present invention is a pellicle frame in a frame shape, which has an upper end face on which a pellicle film is to be arranged and a lower end face to face a photomask.

(5) As long as the pellicle frame has a frame shape, the shape corresponds to the shape of a photomask onto which a pellicle is to be attached. In general, the shape of a pellicle frame is a quadrilateral (rectangular or square) frame shape.

(6) In addition, in a pellicle frame, there are a face on which a pellicle film is to be arranged (herein, referred to as an upper end face) and a face to face a photomask (herein, referred to as a lower end face) when the pellicle frame is attached onto the photomask.

(7) In general, on the upper end face of a pellicle frame, a pellicle film is arranged with an adhesive agent or the like therebetween, and on the lower end face, a pressure-sensitive adhesive or the like for attaching a pellicle onto a photomask is provided, but cases of the present invention are not limited to the above.

(8) The material for a pellicle frame is not limited, and a known material can be used. In a pellicle frame for EUV, since there is a possibility of being exposed to a high temperature, a material having a small thermal expansion coefficient is preferred. As the material for a pellicle frame, Si, SiO.sub.2, SiN, quartz, invar, titanium, a titanium alloy, or the like can be mentioned. Among them, from the viewpoint of the ease of processing or the lightness in weight, titanium, or a titanium alloy is preferably used.

(9) The size of a pellicle frame is not particularly limited, however, since the height of a pellicle for EUV is limited to 2.5 mm or less, the thickness of a pellicle frame for EUV is smaller than the height and is less than 2.5 mm.

(10) In addition, the thickness of a pellicle frame for EUV is preferably 1.5 mm or less in consideration of the thickness of a pellicle film, a mask pressure-sensitive adhesive and the like.

(11) In the pellicle frame according to the present invention, a notched part is provided from an outer side face toward an inner side face of an upper end face of the pellicle frame. Although there are no restrictions on the position to be provided with the notched part and the number of the notched parts, the total area of the opening parts is preferably 20 mm.sup.2 or more, and more preferably 30 mm.sup.2 or more.

(12) In addition, usually, on a side face of a pellicle frame, a jig hole used for handling or peeling off a pellicle from a photomask is provided. The size of the jig hole is 0.5 to 1.0 mm in length (diameter in a case of a circle) in a thickness direction of the pellicle frame. The shape of the hole is not limited, and may be a circle or a rectangle. Further, usually, the jig hole is a hole that does not penetrate from an outer side face to an inner side face, and in addition to the jig hole, a vent hole that penetrates from an outer side face to an inner side face may also be provided. In a case of the vent hole, there are no restrictions on the position to be provided with the vent hole and the number of the vent holes.

(13) In addition, a filter may be arranged in a notched part formed from an outer side face up to an inner side face of a pellicle frame. In that case, a filter may be arranged on either the inner side face or the outer side face of the pellicle frame so as to cover the notched part.

(14) In the pellicle according to the present invention, a pellicle film is arranged on an upper end face of the pellicle frame as described above with a pressure-sensitive adhesive or an adhesive agent therebetween. The material for the pressure-sensitive adhesive or the adhesive agent is not limited, and a known material can be used. The pressure-sensitive adhesive or the adhesive agent is arranged on an upper end face excluding the notched parts of the pellicle frame. In order to strongly hold the pellicle film, a pressure-sensitive adhesive or adhesive agent having a strong adhesive force is preferred.

(15) On the material for the pellicle film described above, there are no particular restrictions, and a material having a high transmittance and a high light resistance, at a wavelength of an exposure light source is preferred. For example, an ultrathin silicon film, a carbon film, or the like is used for EUV exposure.

(16) Further, on a lower end face of the pellicle frame, a mask pressure-sensitive adhesive for attaching the pellicle frame onto a photomask is formed. In general, the mask pressure-sensitive adhesive is preferably arranged over the entire circumference of the pellicle frame.

(17) As the above-described mask pressure-sensitive adhesive, a known pressure-sensitive adhesive can be used, and an acrylic pressure-sensitive adhesive or a silicone-based pressure-sensitive adhesive can be suitably used. The pressure-sensitive adhesive may be processed into an arbitrary shape as needed.

(18) Onto a lower end face of the above-described mask pressure-sensitive adhesive, a release layer (separator) for protecting the pressure-sensitive adhesive may be attached. There are no particular restrictions on a material for the release layer, and for example, polyethylene terephthalate (PET), polytetrafluoroethylene (PTFE), tetrafluoroethylene-perfluoroalkyl vinyl ether copolymer (PFA), polyethylene (PE), polycarbonate (PC), polyvinyl chloride (PVC), polypropylene (PP), or the like can be used. Further, as needed, a release agent such as a silicone-based release agent or a fluorine-based release agent may be applied onto a surface of the release layer.

(19) Herein, FIG. 1 shows an example of a pellicle frame 1 according to the present invention, and in each drawing, the reference sign 11 shows an inner side face of the pellicle frame, the reference sign 12 shows an outer side face of the pellicle frame, the reference sign 13 shows an upper end face of the pellicle frame, and the reference sign 14 shows a lower end face of the pellicle frame. In the upper end face of the pellicle frame 1 of FIG. 1, notched parts 10 and 10 are provided on the short sides, respectively, and not provided on the long sides, in the upper end face. In addition, usually, on the long side of the pellicle frame, a jig hole used for peeling off a pellicle from a photomask is provided, however, the jig hole is not specifically shown in FIG. 1.

(20) FIGS. 2A and 2B show an example in which in an upper end face of a pellicle frame 1, notched parts 10 and 10 are provided on the short sides in the upper end face, respectively, and further notched parts 10 and 10 are provided also on the long sides in the upper end face, respectively, that is, a total of four notched parts are provided in the upper end face. In FIGS. 2A and 2B, the notched parts are each formed by communicating from an outer side face up to an inner side face. In FIGS. 2A and 28, the reference sign W shows a width of the notched part, the reference sign D shows a depth of the notched part, and the reference sign T shows a height of the notched part.

(21) FIG. 3 shows a pellicle 20, and a pellicle film 2 is bonded and stretched onto an upper end face of a pellicle frame 1 by an adhesive agent 4. Further, the pellicle frame 1 is peelably bonded to a photomask 3 by a pressure-sensitive adhesive 5 to protect a pattern surface on the photomask 3.

EXAMPLES

(22) Hereinafter, the present invention is specifically described with reference to Examples and Comparative Examples, however, the present invention is not limited to the following Examples.

Example 1

(23) A pellicle frame (with an outer size of 150 mm×118 mm×1.5 mm, and a frame width of 4.0 mm) made of titanium (having a linear expansion coefficient of 8.4×10.sup.−6 (1/K), and a density of 4.5 g/cm.sup.3) was prepared.

(24) In an outer side face of a long side of the pellicle frame, two jig holes each having a diameter of 1 mm and a depth of 1.2 mm were provided at two places each with a distance of 52 mm away from the center of the side to each of the corner directions. A notched part with a width of 90 mm, a height of 0.1 mm, and a depth of 4 mm was provided in an upper end face at the center of each of the sides of the pellicle frame. The notched part was formed from an outer side face up to an inner side face.

(25) The pellicle frame was cleaned, and one obtained by adding 1 part by weight of a curing agent (PT-56 manufactured by Shin-Etsu Chemical Co., Ltd.) into 100 parts by weight of a silicone pressure-sensitive adhesive (X-40-3264 manufactured by Shin-Etsu Chemical Co., Ltd.) and stirring the mixture was applied on the upper end face excluding the notched parts of the pellicle frame so as to have a width of 1 mm and a thickness of 0.1 mm. Further, as a mask pressure-sensitive adhesive, one obtained by adding 0.1 part by weight of a curing agent (L-45 manufactured by Soken Chemical & Engineering Co., Ltd.) into 100 parts by weight of an acrylic pressure-sensitive adhesive agent (SK-1495 manufactured by Soken Chemical & Engineering Co., Ltd.) and stirring the mixture was applied over the entire circumference on a lower end face of the pellicle frame so as to have a width of 1 mm and a thickness of 0.1 mm.

(26) After that, the pellicle frame was heated at 90° C. for 12 hours to cure the pressure-sensitive adhesive on the upper end face and lower end face of the pellicle frame. Subsequently, an ultrathin silicon film was used as a pellicle film, and the ultrathin silicon film was press bonded to the pressure-sensitive adhesive formed on the upper end face of the pellicle frame, and a pellicle was completed.

(27) The pellicle was attached onto a quartz mask with a size of 150 mm×150 mm as a substitute for a photomask.

Example 2

(28) A pellicle frame (with an outer size of 150 mm×118 mm×1.5 mm, and a frame width of 4 mm) made of titanium was prepared.

(29) In an outer side face of a long side of the pellicle frame, two jig holes each having a diameter of 1 mm and a depth of 1.2 mm were provided at two places each with a distance of 52 mm away from the center of the side to each of the corner directions. In an upper end face of each of the long sides of the pellicle frame, two notched parts each with a width of 50 mm, a height of 0.1 mm and a depth of 4 mm were provided at two places with a space of 15 mm. In an upper end face of each of the short sides of the pellicle frame, two notched parts each with a width of 40 mm, a height of 0.1 mm and a depth of 4 mm were provided at two places with a space of 15 mm. These notched parts were each formed from an outer side face up to an inner side face.

(30) The pellicle frame was cleaned, and one obtained by adding 1 part by weight of a curing agent (PT-56 manufactured by Shin-Etsu Chemical Co., Ltd.) into 100 parts by weight of a silicone pressure-sensitive adhesive (X-40-3264 manufactured by Shin-Etsu Chemical Co., Ltd.) and stirring the mixture was applied on the upper end face excluding the notched parts of the pellicle frame so as to have a width of 1 mm and a thickness of 1 mm. Further, a silicone pressure-sensitive adhesive similar to the above pressure-sensitive adhesive was also applied over the entire circumference on a lower end face of the pellicle frame so as to have a width of 1 mm and a thickness of 1 mm.

(31) After that, the pellicle frame was heated at 90° C. for 12 hours to cure the pressure-sensitive adhesive on the upper end face and lower end face of the pellicle frame. Subsequently, an ultrathin silicon film was used as a pellicle film, and the ultrathin silicon film was press bonded to the pressure-sensitive adhesive formed on the upper end face of the pellicle frame, and a pellicle was completed.

(32) The pellicle was attached onto a quartz mask with a size of 150 mm×150 mm as a substitute for a photomask.

Comparative Example 1

(33) A pellicle frame (with an outer size of 150 mm×118 mm×1.5 mm, and a frame width of 4 mm) made of titanium was prepared. Instead of providing a notched part on each side of the pellicle frame, through holes each having a diameter of 0.8 mm were provided at 20 positions on each side as ventilation parts. The constitution except for the constitution described above was the same as the constitution of Example 1.

Comparative Example 2

(34) A pellicle frame (with an outer size of 150 mm×118 mm×1.5 mm, and a frame width of 4 mm) made of titanium was prepared. The constitution was the same as the constitution of Example 1 except that a notched part was provided at the center of each side in the lower end face of the pellicle frame.

(35) The pellicle of each example of Examples 1 and 2 and Comparative Examples 1 and 2 was subjected to the following attachment stability test, ventilation test, and foreign matter inspection after cleaning. The evaluation results are shown in Table 1.

(36) [Attachment Stability Test]

(37) A pellicle attached to a quartz substrate was placed so that the pellicle was positioned on the lower side, heated to 80° C. in an oven, and left to stand for 1 week, and the presence or absence of the dropping of the pellicle was confirmed. As a result, only the pellicle of Comparative Example 2 was dropped.

(38) [Ventilation Test]

(39) A pellicle attached to a quartz substrate was placed in a vacuum device, and the pressure was reduced to 1E-4 (1.0×10.sup.−4) Pa in 1 minute. After that, the pressure was returned to an atmospheric pressure over 2 minutes, and the state of the pellicle film was confirmed. In all of the pellicle films of Examples 1 and 2 and Comparative Examples 1 and 2, abnormality was not confirmed.

(40) [Foreign Matter Inspection after Cleaning]

(41) After cleaning a pellicle frame, adhered foreign matters on a surface of the pellicle frame was inspected by using a condensing light under a fluorescent lamp and in a dark room, and the adhered foreign matters were not confirmed in all of the pellicle films of Examples 1 and 2 and Comparative Examples 1 and 2.

(42) In Comparative Example 1, since the presence or absence of foreign matters inside a through hole cannot be confirmed by visual inspection, the presence or absence of foreign matters inside the through hole was confirmed by using a microscope after cleaning the pellicle frame. Of the 80 through holes, a foreign matter with a size of around 100 μm was found in two through holes. Further, since the visual observation was performed by using a microscope, many foreign matters adhered to a surface of the pellicle frame due to the use of the microscope.

(43) TABLE-US-00001 TABLE 1 Attachment Ventilation Foreign matter Material stability characteristic inspection Example 1 Titanium ○ ○ ○ Example 2 Titanium ○ ○ ○ Comparative Titanium ○ ○ x Example 1 Comparative Titanium x ○ ○ Example 2

(44) From the above Table 1, in each of the pellicles of Examples 1 and 2, by using a pellicle frame having a notched part in an upper end part of the pellicle frame, the foreign matter inspection can be more easily performed as compared with the pellicles of Comparative Examples 1 and 2, and it can be understood that the attachment stability is favorable, and the ventilation ability is sufficient.

(45) Japanese Patent Application No. 2019-016992 is incorporated herein by reference.

(46) Although some preferred embodiments have been described, many modifications and variations may be made thereto in light of the above teachings. It is therefore to be understood that the invention may be practiced otherwise than as specifically described without departing from the scope of the appended claims.