Alignment device for aligning the first substrate with the second substrate.

Abstract

This invention provides a means to enable the technically simple and reliable method of aligning a wafer in close proximity to a mask. [Solution] The alignment device 10 comprises a first substrate holder 12 for holding a first substrate 14 and a second substrate holder 16 for holding a second substrate 18, wherein the first and second substrate holders are mounted so as to be able to adjust the distance between them. Furthermore, it comprises a distance control element 20 that can be inserted between the first and second substrate holders. The distance control element comprises a main body 22. The main body has a fluid inlet 24, a first substrate fluid outlet 26 connected to the fluid inlet that injects pressurized fluid from the main body toward the first substrate when the first substrate is placed in the first substrate holder, and a second substrate fluid outlet 28 connected to the fluid inlet that injects pressurized fluid from the main body toward the second substrate when the second substrate is placed in the second substrate holder.

Description

Technical Field

[0001] The present invention relates to an alignment apparatus for aligning a first substrate with respect to a second substrate.

Background Art

[0002] In manufacturing components having fine or nano structures such as semiconductor devices, it is often necessary to align a first substrate (e.g., a wafer) with respect to a second substrate (e.g., a mask) with high precision.

[0003] The wafer and the mask are typically placed in a state close to each other, and then relatively moved horizontally with respect to each other to achieve a desired alignment.

[0004] However, due to warping of the wafer and / or the mask, or incompleteness in the alignment process, undesirable local contact may occur between the mask and the wafer, resulting in scratches and even more serious damage to the wafer and / or the mask.

[0005] In order to improve process control, during alignment, for example, a spherical spacer made of a small ceramic ball can be disposed between the mask and the wafer. The spherical spacer forms a Hertz contact with respect to the wafer and the mask, and while the wafer and the mask are relatively moved horizontally with respect to each other, rotation of the spherical spacer prevents scratches from occurring on the mask or the wafer.

[0006] However, there are also some drawbacks to using spherical spacers. Since spherical spacers typically have a small size of less than 2 mm, they are difficult to handle. Furthermore, the use of spherical spacers is limited to regions of the mask and the wafer that do not have geometric structures or surfaces sensitive to contact.

[0007] Therefore, the object of the present invention is to provide a means that enables the alignment of a wafer in close proximity to a mask to be performed in a technically simple and reliable manner. [Overview of the Initiative]

[0008] The object of the present invention is solved by an alignment device for aligning a first substrate (e.g., a wafer) with respect to a second substrate (e.g., a mask). The alignment device comprises a first substrate holder for holding the first substrate and a second substrate holder for holding the second substrate. The first and second substrate holders are mounted so as to be at an adjustable distance from each other. The alignment device further comprises a distance control element that can be inserted between the first and second substrate holders. The distance control element comprises a body and a fluid inlet provided in the body. The main body has a first substrate fluid outlet connected to the fluid inlet and positioned toward the first substrate holder, configured to inject pressurized fluid from the main body toward the first substrate when the first substrate is positioned in the first substrate holder, and a second substrate fluid outlet connected to the fluid inlet and positioned toward the second substrate holder, configured to inject pressurized fluid from the main body toward the second substrate when the second substrate is positioned in the second substrate holder.

[0009] The pressurized fluid mentioned above is, for example, pressurized air, nitrogen, or an inert gas.

[0010] By injecting pressurized fluid in the direction of the first substrate and the direction of the second substrate, a fluid cushion, such as an air cushion, is formed between the distance control element and the second substrate, and between the distance control element and the first substrate. The fluid cushion prevents physical contact between the distance control element and the second substrate, between the distance control element and the first substrate, and ultimately between the second substrate and the first substrate. Therefore, the second substrate and the first substrate can be aligned while moving relative to each other in close proximity without physical contact with a rigid object, and as a result, the risk of damage to the second substrate and / or the first substrate can be reduced.

[0011] In particular, the first substrate is a wafer, and / or the second substrate is a mask. Therefore, the alignment apparatus according to the present invention is particularly suitable for lithography applications.

[0012] Alternatively, the first substrate may be a mask, an imprint stamp, or any other type of substrate, and / or the second substrate may be a wafer, an imprint stamp, or any other type of substrate. Therefore, the alignment device according to the present invention can be used in a variety of applications.

[0013] In a preferred embodiment, the distance between the distance control element and the first substrate, and / or the distance between the distance control element and the second substrate, can be controlled by adjusting the pressure of the pressurized fluid. In other words, the distance control element can be used as a distance setting element to set a desired distance between the first substrate and the second substrate by injecting pressurized fluid at a predetermined pressure through its respective fluid outlets.

[0014] Additionally or alternatively, the distance control element can be used as a distance measuring element to measure the distance between the distance control element and the first substrate, and / or the distance between the distance control element and the second substrate, and / or the distance between the first substrate and the second substrate, by monitoring or measuring the pressure of the fluid ejected from each fluid outlet. The measured distance can be used as input in a subsequent step, for example, in subsequent wedge error correction. The wedge error correction can be performed by the distance control element functioning as a distance setting element, or by other distance setting means, such as actuators (in particular, piezo actuators) that control the tilt of the first substrate holder and / or the second substrate holder.

[0015] In one technically feasible embodiment, the body of the distance control element is formed by two plates spaced apart from each other and a fluid-impermeable connector connecting the two plates along their peripheries. The plates are, for example, metal plates.

[0016] The above-mentioned connection is, for example, a weld line. By welding the two plates, a highly reliable and durable connection can be formed. Furthermore, compared to other connection methods that rely on, for example, rubber sealing elements, the rigidity of the main body can be increased, and handling becomes easier, especially when inserting the main body between the first substrate and the second substrate.

[0017] According to one aspect of the present invention, the distance control element comprises at least one spacer positioned between the two plates. The spacer precisely defines the distance between the two plates. Thus, a clearly defined channel is formed between the two plates, through which the pressurized fluid flows from the fluid inlet to the respective fluid outlets. Furthermore, the spacer can prevent the channel from collapsing even if a force is accidentally applied to either of the plates.

[0018] In yet another embodiment, the second substrate fluid outlet and the first substrate fluid outlet of the distance control element are formed by through-holes that extend through both of the two plates. This can be easily achieved technically by drilling or laser cutting through the two plates in a single processing step. Furthermore, the through-holes provide a balanced fluid flow in opposite directions. As a result, the force caused by the pressurized fluid flowing on the surfaces of the second and first substrates is uniformly distributed, thus improving process control.

[0019] Furthermore, it is also conceivable that the main body of the distance control element comprises at least one additional second substrate fluid outlet and at least one additional first substrate fluid outlet, where each second substrate fluid outlet forms a fluid outlet pair with one of the first substrate fluid outlets, and the fluid outlet pairs are distributed and arranged across the main body.

[0020] Of course, the distance control element described above may include more than two fluid outlet pairs, for example, 50 or 100 fluid outlet pairs.

[0021] The two or more fluid outlet pairs described above allow for a uniform distribution of the force generated by the pressurized fluid injected toward the second substrate and the first substrate. This makes it possible to precisely control the distance across the entire surface of the first substrate and the second substrate.

[0022] In yet another embodiment of the alignment device, the body of the distance control element comprises at least two fluid channels, each fluid channel connected to at least one fluid outlet pair, and each fluid channel is configured to be supplied with pressurized fluid at a predetermined fluid pressure independently of the other fluid channels.

[0023] This allows pressurized fluid to be injected from different fluid outlet pairs at different pressures. For example, pressurized fluid can be injected from one of the fluid outlet pairs at a first pressure toward predetermined areas of the first and second substrates, and pressurized fluid can be injected from another fluid outlet pair at a second pressure different from the first pressure toward other areas of the first and second substrates. Therefore, different forces can be applied to the first and second substrates at different lateral positions. By precisely adjusting the fluid pressure, and thus the force, acting on the second and first substrates, the distance between them can be locally adjusted. In this way, wedge errors can be corrected.

[0024] In another embodiment, the alignment device further comprises a fluid supply unit for supplying pressurized fluid to the fluid inlet of the distance control element, and a control unit configured to control the fluid pressure of the pressurized fluid supplied to the distance control element. By controlling the fluid pressure, the local or average distance between the first substrate and the second substrate can be adjusted. For example, increasing the fluid pressure increases the force pressing the second substrate and the first substrate, and consequently their respective holders, in a direction that separates them from each other, thereby increasing the distance between them.

[0025] Of course, the alignment device may further include means for reducing the local or overall distance between the second substrate and the first substrate. Such means include, for example, a mechanism that applies force to the second substrate holder and / or the first substrate holder to press them together, or elastic elements connecting the holders.

[0026] In yet another embodiment, the alignment device further comprises a pressure sensor configured to measure the fluid pressure of a pressurized fluid supplied to the distance control element. The control unit is configured, for example, to determine the local distance between the first substrate and the second substrate based on the measured fluid pressure. In other words, the pressurized fluid can be used not only to adjust the distance but also to measure the distance between the second substrate and the first substrate.

[0027] According to another aspect of the present invention, the alignment device further comprises at least a second distance control element insertable between the first substrate holder and the second substrate holder. The second distance control element may have the same structure as the first distance control element. The second distance control element comprises a second body and a second fluid inlet provided on the second body. The second body further comprises a second first substrate fluid outlet connected to the second fluid inlet and positioned toward the first substrate holder, configured to inject pressurized fluid from the second body toward the first substrate when the first substrate is positioned in the first substrate holder, and a second second substrate fluid outlet connected to the second fluid inlet and positioned toward the second substrate holder, configured to inject pressurized fluid from the second body toward the second substrate when the second substrate is positioned in the second substrate holder. The control unit described above is configured to independently control the fluid pressure of the pressurized fluid supplied to different distance control elements.

[0028] By using two or more distance control elements, pressurized fluid can be injected at different pressures at different lateral positions of the second substrate and the first substrate. For example, from one of the distance control elements, pressurized fluid is injected at a first pressure toward a predetermined region of the first substrate and the second substrate, and from another distance control element, pressurized fluid is injected at a second pressure different from the first pressure toward another region of the first substrate and the second substrate. Therefore, different forces can be applied at different lateral positions of the first substrate and the second substrate. By precisely adjusting the fluid pressure, and thus the force, acting on the second substrate and the first substrate, the distance between them can be locally adjusted. In this way, the wedge error can be corrected.

Brief Description of the Drawings

[0029] Hereinafter, further advantages and features of the present invention will become apparent from the description of the present invention and the accompanying drawings. The accompanying drawings illustrate non-limiting embodiments of the present invention, [Figure 1] FIG. 1 is a side view schematically showing a first embodiment of an alignment apparatus according to the present invention. [Figure 2] FIG. 2 is a side view schematically showing a second embodiment of an alignment apparatus according to the present invention. [Figure 3] FIG. 3 is a side view schematically showing a third embodiment of an alignment apparatus according to the present invention. <0000I01>

Embodiments for Carrying Out the Invention

[0030] FIG. 1 schematically shows a first embodiment of an alignment apparatus ˈ0. This alignment apparatus ˈ0 includes a first substrate holder ˈ2 for holding a first substrate ˈ4 and a second substrate holder ˈ6 for holding a second substrate ˈ8.

[0031] It should be noted that in the original text, there is an unclear tag which is translated as <0000I01> here. You may need to check and correct it according to the actual situation. Also, the reference numbers in the text seem to be a bit disordered in terms of the normal numbering logic for FIGS. 1 - 3. You might want to review and adjust this part if it's for a more formal presentation.In the following description, all embodiments of the alignment device 10 will be explained using the example where the first substrate holder 12 is a wafer holder 13, the first substrate 14 is a wafer 15, the second substrate holder 16 is a mask holder 17, and the second substrate 18 is a mask 19. However, this is merely an example and does not limit the present invention.

[0032] For example, the first substrate 14 and / or the second substrate 18 may be a wafer, a mask, an imprint stamp, or any other type of substrate.

[0033] The wafer holder 13 and the mask holder 17 are mounted so that the distance between them can be adjusted.

[0034] The alignment device 10 further includes a distance control element 20 that can be inserted between the wafer holder 13 and the mask holder 17. This distance control element 20 allows the mask 19 held in the mask holder 17 and the wafer 15 held in the wafer holder 13 to be aligned relative to each other with a predetermined distance between them.

[0035] The distance control element 20 comprises a main body 22, which has a fluid inlet 24, a first substrate fluid outlet 26, and a second substrate fluid outlet 28.

[0036] In the following description, all embodiments of the distance control elements 20 and 52 are explained using the example where the first substrate fluid outlets 26 and 58 are wafer fluid outlets 27 and 59, and the second substrate fluid outlets 28 and 60 are mask fluid outlets 29 and 61. However, this is merely an example and does not limit the present invention.

[0037] The main body 22 is formed by two metal plates 30 arranged at a distance from each other, and a fluid-impermeable connecting portion 32 that connects these two plates 30 along their periphery. The connecting portion 32 is, for example, a weld line.

[0038] The distance control element 20 further includes a plurality of spacers 34 positioned between the two plates 30, thereby holding the two plates 30 at a predetermined distance from each other, and forming a fluid channel 36 between them that connects the fluid inlet 24 to each fluid outlet 26, 28 or 27, 29.

[0039] In the embodiment shown in Figure 1, both the mask fluid outlet 29 and the wafer fluid outlet 27 are formed by through-holes 38 that extend through both of the two plates 30.

[0040] The distance control element 20 may be positioned such that the wafer fluid outlet 27 is directed toward the wafer holder 13 and the mask fluid outlet 29 is directed toward the mask holder 17.

[0041] The alignment device 10 further includes a fluid supply unit 40 (e.g., an air compressor) for supplying pressurized fluid to the fluid inlet 24 of the main body 22, and a control unit 42 for controlling the fluid pressure of the pressurized fluid supplied to the fluid inlet 24.

[0042] To control the distance between the wafer 15 and the mask 19, the fluid supply unit 40 can supply pressurized fluid to the fluid inlet 24 of the body 22 of the distance control element 20.

[0043] The pressurized fluid flows through the fluid channel 36 to the wafer fluid outlet 27 and the mask fluid outlet 29.

[0044] The pressurized fluid is then injected from the main body 22 towards the wafer 15 through the wafer fluid outlet 27 when the wafer 15 is held in the wafer holder 13, and towards the mask 19 through the mask fluid outlet 29 when the mask 19 is held in the mask holder 17.

[0045] The injected pressurized fluid forms fluid cushions 44 between the distance control element 20 and the mask 19, and between the distance control element 20 and the wafer 15. The fluid cushions 44 exert forces on the wafer 15 and the mask 19. These forces press the wafer 15 and the mask 19, and consequently their respective holders 13 and 17, apart from each other, or at least prevent them from approaching each other and coming into contact.

[0046] In the embodiment shown in Figure 1, the control unit 42 can control the fluid pressure and therefore the distance between the wafer 15 and the mask 19. That is, the distance control element 20 functions as a distance setting element for setting the distance between the wafer 15 and the mask 19.

[0047] Optionally, the alignment device 10 may further include means 46 for reducing the local or overall distance between the mask holder 17 and the wafer holder 13. For example, a mechanism for applying a predetermined force to the mask holder 17, the wafer holder 13, or both, to bring them closer to each other or prevent them from separating by at least a certain distance.

[0048] The alignment device 10 shown in Figure 1 further includes a pressure sensor 48 configured to measure the fluid pressure of the pressurized fluid supplied to the distance control element 20. The control unit 42 is configured to determine the distance between the wafer 15 held in the wafer holder 13 and the mask 19 held in the mask holder 17 based on the measured fluid pressure. That is, the distance control element 20 also functions as a distance measuring element that measures the distance between the wafer 15 and the mask 19 by monitoring or measuring the pressure of the fluid ejected through the fluid outlets 27, 29. The measured distance can be used as input for subsequent wedge error correction. Wedge error correction can be performed by the distance control element 20, which functions as a distance setting element, or by other distance setting means such as actuators (particularly piezo actuators) that control the tilt of the wafer holder 13 and / or the mask holder 17.

[0049] Figure 2 schematically shows a second embodiment of the alignment device 10 according to the present invention. Since the second embodiment shares several essential points with the first embodiment, only the differences will be described below. The same reference numerals are used for identical or functionally identical components.

[0050] In the second embodiment, the main body 22 has at least one additional mask fluid outlet 29 and at least one additional wafer fluid outlet 27. That is, the main body 22 has two or more wafer fluid outlets 27 and two or more mask fluid outlets 29.

[0051] Each mask fluid outlet 29 forms a fluid outlet pair 50 with one of the wafer fluid outlets 27. The fluid outlet pairs 50 are uniformly distributed across the main body 22.

[0052] The alignment device 10 shown in Figure 2 further comprises two or more fluid channels 36. Each fluid channel 36 is connected to at least one fluid outlet pair 50.

[0053] The fluid pressure of the pressurized fluid supplied to the different fluid channels 36 can be individually adjusted by the control unit 42.

[0054] This makes it possible to inject pressurized fluid from different fluid outlet pairs 50 at different pressures, and as a result, different forces can be applied to the wafer 15 and mask 19 at different lateral positions. These different forces are schematically shown in Figure 2 by double-headed arrows of different sizes.

[0055] By precisely adjusting the fluid pressure of each fluid channel 36, and consequently the forces acting on the mask 19 and wafer 15 in different regions, the distance between them can be locally adjusted. In this way, wedge errors can be corrected.

[0056] Figure 3 schematically shows a third embodiment of the alignment device 10 according to the present invention. Since the third embodiment shares several essential points with the first and second embodiments, only the differences will be described below. The same reference numerals are used for identical or functionally identical components.

[0057] In the third embodiment, the alignment device 10 includes a second distance control element 52 that can be inserted between the wafer holder 13 and the mask holder 17.

[0058] The second distance control element 52 comprises a second body 54, which has a second fluid inlet 56 and a second wafer fluid outlet 59. The second wafer fluid outlet 59 is connected to the second fluid inlet 56 and is positioned toward the wafer holder 13, and is configured to inject pressurized fluid from the second body 54 toward the wafer 15 when the wafer 15 is held in the wafer holder 13.

[0059] The second body 54 further has a second mask fluid outlet 61. The second mask fluid outlet 61 is connected to the second fluid inlet 56 and is positioned toward the mask holder 17, and is configured to inject pressurized fluid from the second body 54 toward the mask 19 when the mask 19 is held in the mask holder 17.

[0060] In the third embodiment, the control unit 42 is configured to independently control the fluid pressure of the pressurized fluid supplied to different distance control elements 20 and 52.

[0061] This makes it possible to inject pressurized fluid from different bodies 22 and 54 at different pressures, and as a result, different forces can be applied to the wafer 15 and mask 19 at different lateral positions.

[0062] Similar to the second embodiment, the force acting on the mask 19 and wafer 15, and consequently the distance between them, can be locally adjusted by individually adjusting the fluid pressure of the pressurized fluid supplied to both distance control elements 20 and 52.

[0063] This makes it possible to precisely and non-contact control the distance between the mask 19 and the wafer 15 during the alignment process, particularly during the alignment process in which the mask 19 and the wafer 15 are moved relative to each other in the lateral direction.

Claims

1. An alignment device for aligning a first substrate (14) with respect to a second substrate (18), A first substrate holder (12) for holding the first substrate (14) described above, A second substrate holder (16) for holding the second substrate (18) and Equipped with, The first substrate holder (12) and the second substrate holder (16) are mounted so that their distance from each other can be adjusted. The device includes a distance control element (20) that can be inserted between the first substrate holder (12) and the second substrate holder (16). The distance control element (20) described above comprises a main body (22), The above main body (22) is, Fluid inlet (24) and A first substrate fluid outlet (26) is connected to the fluid inlet (24) and positioned toward the first substrate holder (12), and is configured to inject pressurized fluid from the main body (22) toward the first substrate (14) when the first substrate (14) is positioned in the first substrate holder (12), A second substrate fluid outlet (28) is connected to the fluid inlet (24) and positioned toward the second substrate holder (16), and is configured to inject pressurized fluid from the main body (22) toward the second substrate (18) when the second substrate (18) is positioned in the second substrate holder (16). has A positioning device characterized by the following features.

2. In the alignment device according to claim 1, The first substrate (14) is a wafer (15), and / or the second substrate (18) is a mask (19). A positioning device characterized by the following features.

3. In the alignment device according to claim 1 or 2, The distance between the distance control element (20) and the first substrate (14), and / or the distance between the distance control element (20) and the second substrate (18) can be controlled by adjusting the pressure of the pressurized fluid. A positioning device characterized by the following features.

4. In the alignment device according to any one of claims 1 to 3, The main body (22) of the distance control element (20) is formed by two plates (30) arranged at a distance from each other, and a fluid-impermeable connecting portion (32) that connects the two plates (30) along their peripheries. A positioning device characterized by the following features.

5. In the alignment device according to claim 4, The above-mentioned connection portion (32) is a weld line. A positioning device characterized by the following features.

6. In the alignment device according to claim 4 or 5, The distance control element (20) includes at least one spacer (34) positioned between the two plates (30). A positioning device characterized by the following features.

7. In the alignment device according to any one of claims 4 to 6, The first substrate fluid outlet (26) and the second substrate fluid outlet (28) are formed by through holes (38) that extend through both of the two plates (30). A positioning device characterized by the following features.

8. In the alignment device according to any one of claims 1 to 7, The main body (22) of the distance control element (20) is provided with at least one additional first substrate fluid outlet (26) and at least one additional second substrate fluid outlet (28), Each second substrate fluid outlet (28) forms a fluid outlet pair (50) with one of the first substrate fluid outlets (26). The fluid outlet pairs (50) are distributed and arranged across the main body (22). A positioning device characterized by the following features.

9. In the alignment device according to claim 8, The main body (22) of the distance control element (20) is equipped with at least two fluid channels (36), Each fluid channel (36) is connected to at least one of the fluid outlet pairs (50), Each fluid channel (36) is configured to be supplied with pressurized fluid at a predetermined fluid pressure independently of the other fluid channels (36). A positioning device characterized by the following features.

10. In the alignment device according to any one of claims 1 to 9, A fluid supply unit (40) for supplying pressurized fluid to the fluid inlet (24) of the distance control element (20), A control unit (42) is configured to control the fluid pressure of the pressurized fluid supplied to the distance control element (20) and Equipped with A positioning device characterized by the following features.

11. In the alignment device according to claim 10, The system further includes a pressure sensor (48) configured to measure the fluid pressure of the pressurized fluid supplied to the distance control element (20), The control unit (42) is configured to determine the local distance between the first substrate (14) and the second substrate (18) based on the measured fluid pressure. A positioning device characterized by the following features.

12. In the alignment device according to claim 10 or 11, The system further includes a second distance control element (52) that can be inserted between the first substrate holder (12) and the second substrate holder (16), The second distance control element (52) described above comprises a second body (54), The second main body (54) described above is The second fluid inlet (56) and A second fluid outlet for the first substrate (58) is connected to the second fluid inlet (56) and positioned toward the first substrate holder (12), and is configured to inject pressurized fluid from the second body (54) toward the first substrate (14) when the first substrate (14) is positioned in the first substrate holder (12), A second second substrate fluid outlet (60) is connected to the second fluid inlet (56) and positioned toward the second substrate holder (16), and is configured to inject pressurized fluid from the second body (54) toward the second substrate (18) when the second substrate (18) is positioned in the second substrate holder (16), and It has, The control unit (42) is configured to independently control the fluid pressure of the pressurized fluid supplied to the distance control element (20) and the second distance control element (52). A positioning device characterized by the following features.

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