JPH07271017A - Pellicle frame for photomask - Google Patents

Abstract

PURPOSE:To obtain a pellicle the superposing accuracy of which is not deteriorated and which is easily detached. CONSTITUTION:This invention is concerning a photomask 7 and a pellicle frame 1 provided inside from the outer edge of the photomask 7. The pellicle frame 1 is constituted of a hollow rectangular parallelopiped and attaching parts extending to the outside on a pair of facing sides of the parallelopiped, and a pellicle film 3 is attached to one surface of the parallelopiped and the photomask 7 is attached to the other surface at four corners of the attaching parts by fixing frames 8 provided in parallel with the sides of the parallelopiped, so that the pellicle frame 1 for the photomask is obtained.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a photomask having a pellicle, which is used for the purpose of preventing foreign matter from adhering to a photomask used for manufacturing a semiconductor device such as an LSI.

[0002]

2. Description of the Related Art A photomask used in a lithography process for manufacturing a semiconductor has a metal film pattern formed on a quartz substrate, and foreign matters attached to the photomask are transferred to the wafer, which greatly reduces the yield. Affect. In the conventional technique, for example, as disclosed in Japanese Patent Laid-Open No. 4-199055, the bottom of a pellicle frame having a pellicle film attached to the upper part of the frame is adhered to the surface of the photomask with an adhesive layer to attach foreign matter to the photomask. Was being prevented.
However, if the pellicle film is damaged, or if the photomask is attached to the device that exposes the wafer, the pellicle film may be damaged.
There is a case where a foreign substance having a size enough to be transferred onto the pellicle is adhered to the pellicle from an operator. In that case, the operator needs to manually peel off the pellicle and reattach a new pellicle. However, since the pellicle frame is strongly adhered to the photomask by the adhesive layer, when reattaching the pellicle, for example, a wedge-shaped metal is adhered to the mask substrate and the adhesive layer via the adhesive layer. Work is performed by pushing in between and floating the pellicle frame from the photomask to remove it, and in this work, there is a high possibility that foreign matter will be generated from the adhesive layer, the pellicle frame, and the like, which further reduces the yield.

Therefore, in order to solve the above problems, a pellicle frame disclosed in Japanese Patent Laid-Open No. 4-81758 is considered. Hereinafter, referring to FIG. 14 to FIG.
The pellicle shown in 81758 will be described. Figure 1
In FIGS. 4 and 15, 511 is a fixing jig, 512 is a pellicle frame, 513 is a photomask, and 522 is a pellicle film.
6, 531 is thin rubber, 532 is a fixing jig, 53
Reference numeral 3 denotes a U-shaped fixing jig, and the pellicle frame 512 is installed such that a portion where the pellicle frame 512 and the photomask 513 are in contact with each other spreads to the outer peripheral portion of the photomask 513 as shown in FIG. The fixing jig 511 is shown in FIGS.
Upper and lower pellicle frame 512 and photomask 513
And the photomask 513 is completely fixed in the two longitudinal directions as shown in FIG.
The fixing jig 533 having the structure shown in FIG. 16 performs the same operation as the fixing jig 511 of FIGS. 14 and 15.

[0004]

When the photomask is set on the stepper, as shown in FIG. 17, the pattern surface of the mask is faced down, and the two adjoining sides of the photomask are formed on the mask stage. It is adsorbed and fixed by. The flatness of the pattern surface of the mask fixed to the stage greatly affects the overlay accuracy of the patterns when transferring the patterns to the wafer. The flatness of the surface of the mask is quite high, and the height variation of a 12 cm square surface is within 2 μm. On the other hand, in the conventional pellicle frame and fixing jig, as shown in FIG.
As shown in FIG. 7, the outer surface of the fixing jig is attracted to the surface where the conventional mask surface is attracted. Further, it is very difficult to bring the flatness of the outer surface of the fixing jig close to that of the mask. As a result, the overlay accuracy of the patterns at the time of transfer is deteriorated. Further, in the conventional pellicle frame, since the pellicle frame and the photomask are fixed by the elasticity of the thin rubber 531 of the fixing jig, the photomask is distorted, which also affects the pattern overlay accuracy. there is a possibility.

[0005]

In a pellicle frame for a photomask according to the present invention, in a photomask and a pellicle frame provided inside an outer edge of the photomask, the pellicle frame is a hollow rectangular parallelepiped. , A pair of facing sides of the rectangular parallelepiped that are attached to each other, and a pellicle film is attached to one of the rectangular parallelepipeds, and the other side of the rectangular parallelepiped is attached to the four corners of the attachment. The photomask is attached by a fixing frame provided in parallel with each other. Furthermore, a surface of the pellicle frame which is in contact with the pattern surface side of the photomask is provided with a first elastic surface, and an auxiliary surface is provided between the surface opposite to the pattern surface of the photomask and the fixing frame according to claim 1. A frame is sandwiched, and the auxiliary frame is provided with a second elastic surface on a contact surface with a surface opposite to the pattern surface of the photomask. Furthermore, a convex portion and a concave portion are provided on a surface of the fixing frame that is in contact with the upper surface of the pellicle frame bottom portion, and a concave portion and a convex portion are provided on the upper surface of the pellicle frame bottom portion,
The pellicle frame for a photomask is installed by combining the convex portion and the concave portion and the concave portion and the convex portion.
Furthermore, a surface that extends laterally inside the fixing frame and is in contact with the auxiliary frame is provided with a convex portion and a concave portion, and a surface of the auxiliary frame that contacts the laterally expanding surface inside the fixing frame. At the concave portion and the convex portion,
The pellicle frame for a photomask is installed by combining the convex portion and the concave portion and the concave portion and the convex portion.

[0006]

Since the fixing frames are installed at the four corners of the bottom of the pellicle frame body in parallel with the installation surface of the stepper, during the exposure, when the photomask is installed on the stepper, the adsorption surface of the stepper is covered by the photomask of the photomask. Since the surface is installed as it is, exposure can be performed while maintaining the flatness of the photomask, and the pattern overlay accuracy does not deteriorate. Since the photomask is sandwiched between the elastic surface of the pellicle frame and the elastic surface of the auxiliary frame, the distortion of the photomask is relieved and the pattern overlay accuracy does not deteriorate. By providing convex parts and concave parts on the fixing frame, pellicle frame, and auxiliary frame and aligning them, the fixing frame can be prevented from being displaced from the pellicle frame and auxiliary frame and can be fixed more firmly, and the pellicle can be fixed during installation on the mask. Prevents dust generation due to displacement from the work frame, pellicle frame, and auxiliary frame. Since the photomask and the pellicle frame are fixed by the fixing frame, they can be easily removed.

[0007]

【Example】

Example 1. FIG. 1 shows a pellicle 6 according to an embodiment of the present invention.
FIG. 2 is a side view showing a state in which is fixed to the photomask 7 using the fixing frame 8, FIG. 2 is a cross-sectional view of the fixing frame 8, and FIG. 3 shows fixing the pellicle 6 to the photomask 7 using the fixing frame 8. FIG. 4 is a cross-sectional view showing the pellicle, and is a top view showing the state in which it is formed. The drawings will be described below. In FIG. 1, 1 is a pellicle frame, 2 is an adhesive, 3 is a pellicle film, 4 is an adhesive,
5 is an elastic material layer as a first elastic surface, 6 is a pellicle as a pellicle structure composed of the pellicle frame 1, adhesive 2, pellicle film 3, adhesive 4 and elastic material layer 5, and 7 is a photomask , 8 is a fixing frame, 15 is a pattern surface side of the photomask, 16 is a glass surface side of the photomask on the side opposite to the pattern surface of the photomask, 111 is a bottom portion of the pellicle frame which spreads as an attachment portion, 150 Is a stepper installation surface, and 151 is a stepper. The pellicle 6 is installed so that the elastic material layer 5 is in contact with the metal film pattern surface side 15 of the photomask 7, and the fixing frame 8 is positioned parallel to the installation surface 150 of the stepper as shown in FIG. The pellicle 6 is fixed to the photomask 7 by sandwiching the four corners 300 of the expanded bottom 111 of the pellicle frame 1. Then, as shown in FIG.
The surface of the photomask 7 is set on the stepper without the fixing frame 8 being in contact with the stepper. As shown in FIG. 4, the pellicle frame 1 is characterized by having a hollow rectangular parallelepiped and an expanded bottom portion 111 having a certain thickness on a pair of facing two sides of the rectangular parallelepiped. The pellicle film 3 is adhered via the adhesive 2. An elastic material layer 5 is adhered to the back surface of the expanded bottom portion 111 of the pellicle frame 1 via an adhesive 4. The pellicle film 3 and the adhesive 2 in this embodiment are the same as those used in the prior art. The fixing frame 8 can be made of metal such as stainless steel or aluminum alloy, or polymer resin such as polyvinyl chloride. Expanded bottom 111 of the pellicle frame 1
A polymer resin such as silicon rubber can be used for the elastic material layer 5 adhered to the back surface of the.

Example 2. 5, 6, and 7, respectively,
FIG. 5 is a view showing another embodiment of the present invention, FIG. 5 is a top view of the auxiliary frame 12, FIG. 6 is an enlarged cross-sectional view of the auxiliary frame 12 taken along the line AA, and FIG. It is a state diagram when installed on the glass surface side 16 and sandwiched by the fixing frame 8a. In FIG. 6, 9 is a frame body of an auxiliary frame, 10 is an adhesive, 11 is an elastic material layer as a second elastic surface, 12 is an auxiliary frame, and in FIG. 7, 8a is a fixing frame. Auxiliary frame 12
5 is a hollow plate having the same top surface shape and size as the expanded bottom portion 111 of the pellicle frame 1 in the first embodiment as shown in FIG. 5, and the structure is bonded to the auxiliary frame body 9 as shown in FIG. Agent 10
This is a structure in which the elastic material layer 11 is adhered via. As shown in FIG. 7, the auxiliary frame 12 is set on the glass surface side 16 of the photomask 7, and the pellicle 6, the photomask 7, and the auxiliary frame 12 are sandwiched by the fixing frame 8a to fix the pellicle 6 to the photomask 7. To do. By installing the auxiliary frame 12 on the glass surface side 16 of the photomask, it is possible to alleviate distortion such as warpage of the photomask due to the stress of pinching the fixing frame 8a, and the fixing frame 8a is directly attached to the quartz substrate. It is possible to eliminate scratches caused by contact with the.

Embodiment 3. 8, 9 and 10 are views showing another embodiment of the present invention. FIG. 8 is a top view when the pellicle 6a is placed on the photomask 7, and FIG. 9 is the pellicle 6a.
8 in FIG. 8 when the photomask 7 is installed on the photomask 7.
FIG. 10 is a sectional view showing a line section, and FIG. 10 is a sectional view of the fixing frame 8b. In the third embodiment, the pellicle frame and the fixing frame in the first embodiment are partially modified. As shown in FIGS. 8 and 9, the pellicle frame 1a includes a bottom portion 11 of the pellicle frame 1a.
A concave portion 100 is formed on the upper surface of 1. Further, in the fixing frame 8b, as shown in FIG.
Convex portion 1 on the surface in contact with the upper surface of the bottom 111 of the pellicle frame
01 is formed. Recessed portion 100 of the pellicle frame 1a
And the convex portion 101 of the fixing frame 8b are aligned, and the pellicle 6a and the photomask 7 are fixed to the fixing frame 8 in the same manner as in the first embodiment.
At the position b, the pellicle 6a and the photomask 7 are fixed with each other. In the first embodiment, the bottom of the pellicle 6 is a flat surface, and the pinching portion of the fixing frame 8 is also a flat surface. However, the concave portion 100 is formed like the pellicle 6a and the convex portion formed on the fixing frame 8b. By combining 101, the pellicle 6a and the photomask 7 can be more firmly fixed to each other. A convex portion may be provided instead of the concave portion 100 of the pellicle frame 1a, and a concave portion may be provided instead of the convex portion 101 of the fixing frame 8b, and the pellicle frame 1a may be fixed together.

Embodiment 4. FIG. 11 is a partial sectional view showing another embodiment of the present invention. In FIG. 11, 102 is a convex portion provided on the pellicle frame 1b, and 103 is an auxiliary frame 12
Reference numeral 104 denotes a concave portion provided on a, and reference numeral 104 denotes a convex portion provided on the auxiliary frame 12b. 11 (a), (b), (c), (d)
Shows the modification of Example 2, respectively. In FIG. 11A, the pellicle frame 1a, the adhesive 2, the pellicle film 3, the adhesive 4, and the elastic material layer 5 constitute a pellicle 6a.
(A) shows a state in which the photomask 7 is sandwiched between the pellicle 6a and the auxiliary frame 12a. In FIG. 11B, the pellicle frame 1b, the adhesive 2, the pellicle film 3, the adhesive 4, and the elastic material layer 5 constitute a pellicle 6b. In FIG. 11B, the pellicle 6b and the auxiliary frame 12a form the photomask 7. It shows how to sandwich. FIG. 11C shows a state in which the photomask 7 is sandwiched between the pellicle 6a and the auxiliary frame 12b. In FIG. 11 (d),
The photomask 7 is sandwiched between the pellicle 6b and the auxiliary frame 12b. In FIG. 12, 105 is a concave portion and 106 is a convex portion. 12 (a), (b), (c), and (d) are fixing frames 8c, 8d, which are modifications of the second embodiment, respectively.
8e and 8f are sectional views. The fixing frame 8c is shown in FIG.
As shown in (a), convex portions 106 are formed on the upper and lower portions, respectively.
Is provided. The convex portion 106 on the upper portion of the fixing frame 8c
11A, the concave portion 100 of the pellicle frame 1a, the lower convex portion 106 of the fixing frame 8c, and the auxiliary frame 1 of FIG. 11A.
Insert the recessed portions 103 of 2a into the pellicle 6a.
The auxiliary frame 12a is fixed and the fixing frame 8c is used.
As shown in FIG. 12B, the fixing frame 8d is provided with a concave portion 105 in the upper portion and a convex portion 106 in the lower portion. The upper concave portion 105 of the fixing frame 8d, the convex portion 102 of the pellicle frame 1b of FIG. 11B, and the lower convex portion 1 of the fixing frame 8d.
06 and the recessed portions 103 of the auxiliary frame 12a in FIG. 11B are fitted respectively, the pellicle 6b and the auxiliary frame 12a are fixed, and the fixing frame 8d is used. The fixing frame 8e is shown in FIG.
As shown in (c), a convex portion 106 is provided on the upper portion and a concave portion 105 is provided on the lower portion. The convex portion 106 on the upper portion of the fixing frame 8e and the concave portion 10 of the pellicle frame 1b of FIG. 11C.
0, the concave portion 105 at the bottom of the fixing frame 8e and FIG.
The convex portions 104 of the auxiliary frame 12b are fitted into each other to fix the pellicle 6a and the auxiliary frame 12b, and the fixing frame 8e.
To use. As shown in FIG. 12D, the fixing frame 8f is provided with a concave portion 105 in the upper portion and a concave portion 105 in the lower portion. The concave portion 105 at the upper part of the fixing frame 8f and FIG.
(D) Convex portion 102 of pellicle frame 1b, fixing frame 8f
The concave portion 105 at the lower part of FIG. 11 and the convex portion 104 of the auxiliary frame 12b in FIG. 11D are fitted into each other, and the pellicle 6b and the auxiliary frame 12b are fixed, and the fixing frame 8f is used. Thus, sandwiched between the fixing frame, the concave portion of the pellicle frame and the convex portion of the fixing frame, the convex portion of the pellicle frame and the concave portion of the fixing frame, the concave portion of the auxiliary frame and the convex portion of the fixing frame, By fixing the pellicle and the auxiliary frame by aligning the convex portion of the auxiliary frame and the concave portion of the fixing frame, it is possible to prevent the fixing frame from being displaced from the pellicle frame and the auxiliary frame, and to fix the pellicle frame more strongly.

Embodiment 5. In the first embodiment, it is possible to prevent the fixing frame from being displaced by adhering a resin such as silicon rubber to the inner side surface of the fixing frame 8.

Embodiment 6. FIG. 13 is a sectional view showing the sixth embodiment. The auxiliary frame 12 in the second embodiment may be the same as the pellicle 6.

[0013]

As described above, according to the present invention, a photomask is obtained which is easy to remove, does not deteriorate the pattern superposition accuracy, further reduces dust emitted from the pellicle, and suppresses a decrease in yield. .

[Brief description of drawings]

FIG. 1 uses a fixing frame in Example 1 of the present invention,
It is a side view showing the state where the pellicle was fixed to the photomask.

FIG. 2 is a cross-sectional view of a fixing frame according to the first embodiment of the present invention.

FIG. 3 is a diagram illustrating a first embodiment of the present invention using a fixing frame,
It is a top view showing the state where the pellicle was fixed to the photomask.

FIG. 4 is a cross-sectional view of a pellicle according to the first embodiment of the present invention.

FIG. 5 is a top view of an auxiliary frame according to the second embodiment of the present invention.

FIG. 6 is a sectional view of an auxiliary frame according to a second embodiment of the present invention.

FIG. 7 is a diagram showing a second embodiment of the present invention using a fixing frame,
It is a side view showing a state where a pellicle and an auxiliary frame are fixed to a photomask.

FIG. 8 is a top view showing a third embodiment of the present invention.

FIG. 9 is a partial cross-sectional view showing a third embodiment of the present invention.

FIG. 10 is a sectional view of a fixing frame according to a third embodiment of the present invention.

FIG. 11 is a partial cross-sectional view of a pellicle and an auxiliary frame according to the fourth embodiment of the present invention.

FIG. 12 is a sectional view of a fixing frame according to a fourth embodiment of the present invention.

FIG. 13 is a sectional view of a pellicle and a photomask according to a sixth embodiment of the present invention.

FIG. 14 is a diagram in which a pellicle frame is attached to a photomask in the related art.

FIG. 15 is a diagram in which a pellicle frame is attached to a photomask in the conventional technique.

FIG. 16 is a view showing a fixing jig used in a conventional technique.

FIG. 17 is a diagram in which a photomask is installed on a stepper in the related art.

[Explanation of symbols]

 1 Pellicle Frame 1a Pellicle Frame 1b Pellicle Frame 2 Adhesive 3 Pellicle Film 4 Adhesive 5 Resilient Material Layer 6 Pellicle 6a Pellicle 6b Pellicle 7 Photomask 8 Fixing Frame 8a Fixing Frame 8b Fixing Frame 8d Fixing Frame 8d Frame 8e Fixing frame 8f Fixing frame 9 Auxiliary frame body 10 Adhesive 11 Resilient material layer 12 Auxiliary frame 12a Auxiliary frame 12b Auxiliary frame 15 Photomask metal film pattern surface side 16 Photomask glass surface side 100 Recessed portion 101 convex part 102 convex part 103 concave part 104 convex part 105 concave part 106 convex part 111 expanded bottom part 300 expanded four bottom corners 511 fixing jig 512 pellicle frame 513 photomask 531 thin rubber 532 fixing jig 533 U-shaped Fixing jig 550 Stepper installation surface

Claims (4)

[Claims] 1. A photomask and a pellicle frame provided inside an outer edge of the photomask, wherein the pellicle frame is a hollow rectangular parallelepiped and a mounting portion extending outward at a pair of opposing sides of the rectangular parallelepiped. The pellicle film is attached to one of the rectangular parallelepipeds, and the photomask is attached to the other of the rectangular parallelepipeds at the four corners of the attachment portion by fixing frames provided in parallel to the sides of the rectangular parallelepiped. A pellicle frame for a photomask, which is characterized in that 2. The pellicle frame for a photomask according to claim 1, wherein a surface of the pellicle frame in contact with the pattern surface side of the photomask is provided with a first elastic surface, and a surface opposite to the pattern surface of the photomask. The auxiliary frame is interposed between the fixing frame and the fixing frame according to claim 1, and in the auxiliary frame, a second elastic surface is provided on a contact surface with a surface opposite to the pattern surface of the photomask. A pellicle frame for a photomask. 3. The convex frame and the concave portion are provided on the surface of the fixing frame which contacts the upper surface of the pellicle frame bottom portion, and the concave portion and the convex portion are provided on the upper surface of the pellicle frame bottom portion. The pellicle frame for a photomask according to claim 1, wherein the pellicle frame for a photomask according to claim 1, wherein the pellicle frame and the concave portion are provided so as to be aligned with each other. 4. A convex portion and a concave portion are provided on a surface that spreads laterally inside the fixing frame and is in contact with the auxiliary frame,
And in the surface of the auxiliary frame, which is in contact with the laterally-extending surface inside the fixing frame, a concave portion and a convex portion are provided, and the convex portion and the concave portion, and the concave portion and the convex portion are combined. The pellicle frame for a photomask according to claim 1, which is installed.