Mask box with anti-static damage and processing method thereof

Abstract

A mask box with anti-static damage and a processing method thereof, the mask box comprising a base and a plurality of supporting elements. The base has a bearing surface, the bearing surface is formed with a groove, and the groove has a bottom surface. The supporting element surrounds the bearing surface of the base and is configured to support a mask. The groove has a depth, the depth extends between the bearing surface and the bottom surface, and the depth is between 300μm and 3400μm, thereby weakening the electrostatic force on the particles on the bearing surface. The present application can effectively weaken the influence of the residual voltage of the mask on the particles on the surface of the base by controlling the processing depth of the groove in the base of the mask box or the distance between the bottom surface of the groove and the downward surface of the mask, thereby reducing the attraction of the particles to the downward surface of the mask and avoiding contamination of the pattern area.

Description

Technical Field

[0001] The invention relates to a mask box and a processing method thereof, in particular to a mask box with anti-static damage capability and a processing method thereof. Background Art

[0002] In the current extreme ultraviolet (EUV) process, the masks involved need to be protected by a dedicated EUV mask box. Figure 1 A mask box for accommodating the EUV mask is shown, having an inner and outer accommodating space defined by an outer box 100 and an inner box 110. The outer box 100 includes a box cover 101 and a base 102, which are combined to define an accommodating space for accommodating the inner box 110. The inner box 110 includes a box cover 111 and a base 112, which are combined by special means to define an accommodating space with a sealed effect to accommodate a mask 120.

[0003] Specifically, when the mask 120 is accommodated in the inner box 110, the edge or bottom of the mask 120 is supported by a plurality of supporting elements 1121 on the base 112, so that the downward surface of the mask 112 is slightly higher than an upward bearing surface 1122 of the mask 120. The upward bearing surface (1122, hereinafter referred to as the bearing surface) is a surface surrounded by a plurality of supporting elements 1121, and the area of ​​the bearing surface 1122 is generally larger than the pattern area of ​​the mask 120 (not shown in the figure). In addition, the bearing surface 1122 is different from the upward contact surface 1123 located around the base 112 for contacting the box cover 111, and the upward contact surface 1123 is generally an annular surface.

[0004] When the mask 120 is taken out of the exposure device, a certain voltage will remain in the mask 120, which is generally greater than 50 V. If the mask 120 in this state is put back into the inner box 110, the particles on the base 112 may be adsorbed to the bottom of the mask 120, and when the particles adhere to the pattern area of ​​the mask 120, the mask 120 will produce pattern defects in the next exposure process.

[0005] Figure 2 Schematic diagram of a continuous process of a charged mask 120 approaching a base 112. A negatively charged mask 120 approaches a base 112, wherein the base 112 is grounded and has no charge, but a particle P exists on an upper surface of the base 112 (such as the aforementioned supporting surface 1122). When the charged mask 120 approaches the base 112 to a certain extent, the electric field generated by the negative charge of the mask 120 causes the upper surface of the base 112 and the particle P to generate positive charges. When the mask 120 is closer to the base 112, the strength of the electrostatic field is sufficient to attract the particle P, causing the particle P to detach from the upper surface of the base 112 and attach to the bottom of the mask 120. Obviously, grounding the base 112 still cannot overcome all the defects caused by static electricity.

[0006] In view of the mask defects caused by static electricity, it is necessary to develop a mask box with anti-static damage to accommodate the mask with static charge. Summary of the invention

[0007] Figure 3 The particle P is shown to be subjected to gravity (Fw) and electrostatic force (Fe), where F is the resultant force, q is the charge, E is the electrostatic field, m is the mass of the particle, g is the gravity constant, V is the voltage, and d is the distance between the bottom of the mask and the upper surface of the base. In other words, the factors that cause the particle P on the base to adhere to the bottom of the mask may include the size (weight) of the particle, the charge of the mask, and the distance from the bottom of the mask to the upper surface of the base.

[0008] Accordingly, the object of the present invention is to provide a mask box with anti-static damage, comprising: a base having a carrying surface, the carrying surface forming a groove, the groove having a bottom surface; and a plurality of supporting elements surrounding the carrying surface of the base and configured to support a mask, so that the groove has a depth, the depth extends between the carrying surface and the bottom surface, the depth is between 300μm and 3400μm, thereby weakening the electrostatic force on the particles on the carrying surface.

[0009] In a specific embodiment, the base further has an upward contact surface, which surrounds the carrying surface and is used to contact a box cover to form a sealed accommodating space.

[0010] In a specific embodiment, the groove has an annular edge, and an area surrounded by the annular edge is equal to or larger than an area of ​​a pattern region of the mask.

[0011] In a specific embodiment, the groove has an annular edge, and an area surrounded by the annular edge is sufficient to cover a pattern area of ​​the mask.

[0012] In a specific embodiment, the groove has a rectangular edge, the rectangular edge has a length and a width, the length is 138 mm, and the width is 110 mm.

[0013] In a specific embodiment, a residual voltage of the mask is greater than 50V, and the depth is at least greater than 400 μm.

[0014] Another object of the present invention is to provide a mask box with anti-static damage, comprising: a base having an upper surface, the upper surface being a curved surface formed by mechanical processing; and a plurality of supporting elements surrounding the upper surface and configured to support a mask, so that a distance is formed between a downward surface of the mask and the upper surface, and the distance is at least greater than 300 μm, thereby weakening the electrostatic force on the particles on the upper surface.

[0015] In a specific embodiment, the base further has an upward contact surface, which surrounds the upper surface and is used to contact a box cover to form a sealed accommodating space.

[0016] In a specific embodiment, an area of ​​the upper surface is equal to or larger than an area of ​​a pattern region of the mask.

[0017] In one embodiment, an area of ​​the upper surface is sufficient to cover a pattern area of ​​the mask.

[0018] In a specific embodiment, the upper surface has a rectangular edge, the rectangular edge has a length and a width, the length is 138 mm, and the width is 110 mm.

[0019] In a specific embodiment, a residual voltage of the mask is greater than 50V, and the spacing is at least greater than 400 μm.

[0020] Another object of the present invention is to provide a method for processing a mask box, which is implemented on a base of a mask box, the base having a bearing surface and a plurality of supporting elements, the plurality of supporting elements surrounding the bearing surface of the base and configured to support a mask. The processing method includes: mechanically processing the bearing surface to form a groove on the bearing surface, the groove having a bottom surface; and processing the groove to have a depth of at least greater than 300 μm due to a residual voltage of the mask.

[0021] In a specific embodiment, when the residual voltage is greater than 50V, the depth is at least greater than 400 μm.

[0022] In a specific embodiment, when the residual voltage is greater than 100 V, the depth is at least greater than 400 μm.

[0023] In a specific embodiment, when the residual voltage is greater than 200 V, the depth is greater than or less than 800 μm.

[0024] In a specific embodiment, when the residual voltage is greater than 400 V, the depth is at least greater than 1600 μm. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] The present invention may be further understood with reference to the following drawings and descriptions. Non-limiting and non-exhaustive examples are described with reference to the following drawings. The components in the drawings are not necessarily to actual size; the emphasis is on illustrating the structure and principle.

[0026] Figure 1 An exploded view of a known mask box is shown.

[0027] Figure 2 Schematic diagram of a continuous process of a charged mask approaching the mask box base.

[0028] Figure 3 Illustration of a particle being affected by electrostatic force and gravity.

[0029] Figure 4 An exploded view of the mask box of the present invention is shown.

[0030] Figure 5 A perspective view of an example mask box base.

[0031] Figure 6 Based on Figure 5 A cross-sectional view of .

[0032] Figure 7 for Figure 5 A top view of the mask box base.

[0033] Figure 8 for Figure 5 A bottom view of the mask box base.

[0034] Fig. 9A Schematic diagram of the relationship between the mask pattern area and the groove coverage area; Fig. 9B The figure shows the distance between the mask and the bottom of the groove.

[0035] Fig.10 A three-dimensional diagram of another embodiment of a mask box base.

[0036] FIG. 11A to FIG. 11D The effects of different residual voltages of the mask, different particle sizes, and different spacings on the net force on the particles are described.

[0037]

Explanation of symbols

[0038] 100 outer boxes

[0039] 101 Lid

[0040] 102 Base

[0041] 110 Inner box

[0042] 111 Lid

[0043] 112 Base

[0044] 1121 Support element

[0045] 1122 upward bearing surface, bearing surface

[0046] 1123 Upward contact surface

[0047] 120 Mask

[0048] P particles

[0049] 200 outer boxes

[0050] 201 Lid

[0051] 202 Base

[0052] 210 Inner box

[0053] 211 Lid

[0054] 212 Base

[0055] 2121 Support element

[0056] 2122 bearing surface

[0057] 2123 Upward contact surface

[0058] 2124 Groove

[0059] 220 Mask

[0060] 600 Bottom

[0061] 601 wall

[0062] D Depth

[0063] 800 Positioning Structure

[0064] 900 Mask

[0065] 901 Mask pattern area

[0066] 902 groove area, groove coverage area

[0067] 903 Bottom

[0068] 904 bearing surface

[0069] G Spacing

[0070] 1001 Wall

[0071] 1002 Upper surface

[0072] 1003 upward contact surface DETAILED DESCRIPTION

[0073] The invention will be more fully described below with reference to the drawings, and specific exemplary embodiments are shown by way of illustration. However, the claimed subject matter may be embodied in many different forms, and thus the construction of the claimed subject matter covered or claimed is not limited to any exemplary embodiment disclosed in this specification; the exemplary embodiments are merely illustrative. Likewise, the invention is intended to provide a reasonably broad scope for the claimed subject matter claimed or covered.

[0074] The term "in one embodiment" used in this specification does not necessarily refer to the same embodiment, and the term "in other (some / certain) embodiments" used in this specification does not necessarily refer to different embodiments. It is intended that, for example, the claimed subject matter includes a combination of all or part of the exemplary embodiments.

[0075] Figure 4 An exploded view of the mask box of the present invention is shown as follows Figure 1 The configuration includes an outer box 200 and an inner box 210. The outer box 200 further includes a box cover 201 and a base 202, both of which define a storage space for accommodating the inner box 210. The inner box 210 further includes a box cover 211 and a base 212, both of which define a storage space for accommodating a mask 220. The improvement of the present invention mainly lies in the structure of the base 212, and other details of the outer box 200 and the inner box cover 211 will be omitted in the subsequent description.

[0076] The base 212 has a plurality of support elements 2121, an upward bearing surface (hereinafter referred to as the bearing surface 2122) and an upward contact surface 2123. The support elements 2121 are located between the bearing surface 2122 and the upward contact surface 2123 and surround the bearing surface 2122. The support elements 2121 can be configured in different forms to support the bottom or side edges of the mask 220. For example, each support element 2121 of the present embodiment has two limit posts for limiting the lateral displacement of the mask 220 and a support pin for contacting the downward surface of the mask to lift the mask above the bearing surface 2122. The height of the support pin can determine a distance between the downward surface of the mask and the bearing surface 2122. The bearing surface 2122 is basically a plane, but in fact, at least a portion of the bearing surface 2122 has a deflection surface formed by machining, which is usually not recognizable by the naked eye. The carrying surface 2122 is further processed to form a groove 2124, which is substantially located at the center of the carrying surface 2122 and surrounded by the carrying surface 2122. When the mask 220 is placed on the supporting element 2121, the pattern area of ​​the mask 220 faces the groove 2124.

[0077] Figure 5 Showing more details of the base 212, while Figure 6 Display according to Figure 5 The dashed line cross-sectional view shows that a groove (not numbered) is formed between the bearing surface 2122 and the upward contact surface 2123 around the base 212, which is used to capture particles that enter from between the box cover 211 and the base 212 when they are combined. Figure 6It is clearly shown that the bearing surface 2122 is higher than the upward contact surface 2123. Such a configuration helps to create a structural barrier, increase the difficulty of the particles falling on the bearing surface 2122, and ensure the cleanliness of the inner box 210. In other possible embodiments, the bearing surface 2122 and the upward contact surface 2123 can be the same height or the bearing surface 2122 is lower, and the groove can also be filled. The groove 2124 is defined by a bottom surface 600 and a wall 601, so that the groove 2124 has a depth D. The depth D is the processing depth, which also refers to the vertical drop from the bearing surface 2122 to the bottom surface 600 of the groove, as shown in the figure, the depth D near the wall 601. Since the groove 2124 is also formed by mechanical processing, the bottom surface 600 may have a deflection phenomenon.

[0078] Figure 7 show Figure 5 A top view of the base 212 shows that the opening of the groove 2124 (defined by the inner edge of the bearing surface) and the bottom surface 600 are rectangular, and the opening and the bottom surface 600 are substantially the same in area. In one embodiment, the length of the rectangle is 138 mm and the width is 110 mm. The groove 2124 is substantially located in the center of the bearing surface 2122, not close to any side. Figure 8 show Figure 5 From the bottom view of the base 212 , it can be seen that a plurality of positioning structures 800 are disposed at the bottom of the base 212 , which are used to position the base 212 in the process machine.

[0079] Fig. 9A This is a top view, which mainly illustrates the relationship between a mask pattern area (901, surrounded by a solid line) of a mask 900 and a base groove area 902. It can be seen that the dotted line can be a circular edge defining the groove opening, and the groove covering area 902 defined by it is at least larger than the mask pattern area 901. In such a configuration, it is ensured that each position of the mask pattern area faces the bottom surface of the groove. Fig. 9B 904 is a side view, which mainly shows that there is a distance G between the downward surface of the mask pattern area 901 and the bottom surface 903 of the groove. According to the height at which the mask is supported, the height of the lower surface 904 of the mask can be very close to the height of the supporting surface of the base, that is, the distance between the lower surface 904 of the mask and the bottom surface 600 of the groove is equivalent to the depth of the groove (such as Figure 6 In one embodiment, the depth D of the groove is between 300 μm and 3400 μm, or between 3400 μm and 3750 μm. In other words, the spacing G is at least greater than 300 μm. Accordingly, when a mask with static electricity is placed on a base, the electrostatic force on the particles on the base supporting surface can be effectively weakened by controlling the depth D of the groove or the spacing G, thereby reducing the chance of the particles being attracted to the downward surface of the mask.

[0080] Fig.10 Another embodiment of the base of the present invention is shown. Figure 5 In comparison, we can see Fig.10 The area of ​​the bearing surface in the base has been greatly reduced while the area covered by the groove has been increased, forming an upper surface 1002 surrounded by a wall 1001, and the height of the wall 1001 is still higher than the upward contact surface 1003 to increase the difficulty of contamination particles entering the upper surface 1002. In some embodiments, the wall 1001 can be omitted, and only the groove as shown in the figure separates the upward contact surface and the upper surface. Similarly, when a gap is formed between a downward surface of the mask placed on the base and the upper surface 1002, and the depth of the upper surface 1002 is properly controlled, for example, the vertical height of the wall 1001 is between 300μm and 3400μm, or the gap between the lower surface of the mask and the upper surface 1002 is at least greater than 300μm, the electrostatic force on the particles on the upper surface of the base can be effectively weakened.

[0081] FIG. 11A to FIG. 11D The effects of different residual voltages of the mask, different particle sizes, and different groove depths on the net force on the particles are explained. Fig.11A The six sizes of particles are shown in the configuration shown in Figures 6 and 9B, especially when these particles are located on the bottom surface 903 of the groove and the residual voltage of the mask is 400V. The relationship curve between the depth D and the net force (net force) on the particles can be seen in which when the depth is greater than 1600μm, the net force of all particles turns negative, indicating that the force direction of the particles is downward, which means that the electrostatic force on these particles is effectively weakened. Similarly, Fig. 11B The curves show the relationship between the depth D and the net force on the particles of these sizes when the residual voltage of the mask is 200V. It can be seen that when the depth is greater than 800μm, the electrostatic force on these particles can be effectively weakened. Fig. 11C The curves show the relationship between the depth D and the net force on the particles of these sizes in an environment where the residual voltage of the mask is 100V. It can be seen that when the depth is greater than 400μm, the electrostatic force on these particles can be effectively weakened. Fig.11D The curves showing the relationship between the depth D and the net force on the particles of these sizes in an environment where the residual voltage of the mask is 50V show that when the depth is greater than 400μm, the electrostatic force on the particles can be effectively weakened. Although the curves of particles of different sizes are not distinguished by color in the figure, those skilled in the art can still distinguish the trend differences of the curves based on the content disclosed in the figure and understand the above description.

[0082] Based on the above description, the present invention proposes a mask box, which effectively weakens the influence of the residual voltage of the mask on the particles on the surface of the base by controlling the processing depth of the groove in the base of the mask box or the distance between the bottom surface (upper surface) of the groove and the downward surface of the mask, thereby reducing the particles from being attracted to the downward surface of the mask and avoiding contamination of the pattern area.

Claims

1. A mask box with anti-static damage, characterized in that: Include: A base having a bearing surface, wherein the bearing surface is formed with a groove, and the groove has a bottom surface; and A plurality of support elements surround the bearing surface of the base and are configured to support a mask, The groove has a depth extending from the supporting surface to the bottom surface, and the depth is between 300 μm and 3400 μm, thereby weakening the electrostatic force on the particles on the supporting surface. The groove has an annular edge, and the area of ​​a region surrounded by the annular edge is equal to or larger than the area of ​​a pattern region of the mask.

2. The mask box according to claim 1, characterized in that: The base also has an upward contact surface, which surrounds the carrying surface and is used to contact a box cover to form a sealed accommodating space.

3. The mask box according to claim 1, characterized in that: The area surrounded by the annular edge covers the pattern area of ​​the mask.

4. The mask box according to claim 1, characterized in that: The groove has a rectangular edge, the rectangular edge has a length and a width, the length is 138 mm, and the width is 110 mm.

5. The mask box according to claim 1, characterized in that: A residual voltage of the mask is greater than 50V, and the depth is at least greater than 400 μm.

6. A mask box with anti-static damage, characterized in that: Include: A base having an upper surface, wherein the upper surface is a deflection surface formed by machining; and A plurality of support elements surround the upper surface and are configured to support a mask so that a gap is formed between a downward surface of the mask and the upper surface, and the gap is at least greater than 300 μm, thereby weakening the electrostatic force on the particles on the upper surface. The base has an annular edge extending between the plurality of support elements and the upper surface, and an area of ​​the upper surface defined by the annular edge is equal to or larger than an area of ​​a pattern region of the mask.

7. The mask box according to claim 6, characterized in that: The base also has an upward contact surface, which surrounds the upper surface and is used to contact a box cover to form a sealed accommodating space.

8. The mask box according to claim 6, characterized in that: The upper surface covers the pattern area of ​​the mask.

9. The mask box according to claim 6, characterized in that: The upper surface has a rectangular edge, the rectangular edge has a length and a width, the length is 138 mm, and the width is 110 mm.

10. The mask box according to claim 6, characterized in that: A residual voltage of the mask is greater than 50V, and the spacing is at least greater than 400 μm.

11. A method for processing a mask box, characterized in that: The method is implemented on a base of a mask box, the base having a bearing surface and a plurality of supporting elements, the plurality of supporting elements surrounding the bearing surface of the base and configured to support a mask, and the processing method includes: The bearing surface is machined to form a groove on the bearing surface, wherein the groove has a bottom surface, wherein the groove has an annular edge, and an area surrounded by the annular edge is equal to or larger than an area of ​​a pattern area of ​​the mask; In response to the mask having a residual voltage, the groove is processed so that the groove has a depth, and the depth is at least greater than 300 μm.

12. The method according to claim 11, characterized in that When the residual voltage is greater than 50V, the depth is at least greater than 400 μm.

13. The method according to claim 11, characterized in that When the residual voltage is greater than 100 V, the depth is at least greater than 400 μm.

14. The method according to claim 11, characterized in that When the residual voltage is greater than 200V, the depth is at least greater than 800 μm.

15. The method according to claim 11, characterized in that When the residual voltage is greater than 400V, the depth is at least greater than 1600 μm.

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