Substrate handling device for wafers

Abstract

The present invention relates to a substrate handling device for a wafer, a substrate handling system for a wafer, and a method for substrate handling. The substrate handling device comprises: an end effector, a straightening ring, and a suction cup. The suction cup is arranged in the straightening ring. At least the straightening ring is releasably attached to the end effector. The first part of the suction cup can be connected to a vacuum supply, and the second part of the suction cup can be attached to the substrate by the reduced pressure provided by the vacuum supply. The suction cup protrudes from the straightening ring under normal pressure. The suction cup is at the same level as the straightening ring under reduced pressure, and in the reduced pressure state, the substrate is held by the suction cup so that the straightening ring contacts the substrate.

Description

Technical Field

[0001] The present invention relates to a substrate handling device for a wafer, a substrate handling system for a wafer and a method for substrate handling. The present invention particularly relates to single wafer handling for thin substrates. Thin substrates refer to substrates from several hundred microns to less than 100 microns. Background Art

[0002] In semiconductor and adjacent industries (packaging, solar panels, etc.), wafer processing and substrate handling in general often requires reliable handling of thin substrates. Reliable means for picking up, placing or replacing substrates from storage cassettes in vertical or horizontal position or for robotic handling in processing tools without scratching, breaking, strongly bending or even cracking the substrates. Thin substrates are those from a few hundred microns to sometimes well below 100 microns.

[0003] As a result of the thinness, these substrates are often very fragile and already warped, thus not forming or appearing a planar substrate when held without a support structure. This natural occurrence of substrate bending, either through stresses in the material or simply gravity, is a major problem when attempting to handle thin wafers, especially when attempting to handle thin substrates with handling tools that hold the substrate in place by applying a certain amount of vacuum at one or more locations on the substrate.

[0004] When a vacuum is applied that is strong enough so that the substrate does not fall off the moving handling device, the following happens in currently existing systems: the substrate is deformed by the vacuum force in addition to the deformation that is already present. This additional deformation leads in many cases to the fact that the vacuum suction is lost and the substrate falls off the handling device or, in some cases, to cracks and breaks due to the additional deformation at the location where the vacuum force was applied.

[0005] WO 2015 / 134258 A1 discloses a wafer handling end effector and a semiconductor manufacturing device including and / or used with the wafer handling end effector. The end effector includes an end effector body and a plurality of wafer contact surfaces, the wafer contact surfaces being supported by the end effector body and configured to form at least partial face-to-face contact with a wafer. The end effector further includes a vacuum distribution manifold extending between a robot proximal end of the end effector body and the plurality of wafer contact surfaces. The end effector also includes a plurality of vacuum openings defined within the plurality of wafer contact surfaces and extending between the plurality of wafer contact surfaces and the vacuum distribution manifold. The end effector further includes a plurality of sealing structures, each of the sealing structures being associated with a respective one of the plurality of wafer contact surfaces.

[0006] When a thin, already curved substrate is contacted by the end effector of, for example, WO 2015 / 134258 A1, the substrate remains curved or curves even more, because the gasket is adjusting its deformation to the given curved state of the substrate. This deformation leads to the fact that the vacuum suction is lost, the substrate falls off the handling device and / or cracks.

[0007] Furthermore, when the vacuum is turned off, there is a significant delay in releasing the wafer from the vacuum holding system. Because the substrate is in close contact with the wafer contact surface of the integrated vacuum source, it takes between hundreds of microseconds to several seconds before the vacuum is weak enough to release the wafer. In large manufacturing operations that process hundreds of thousands of wafers per day, this release delay results in significant processing and manufacturing delays. Summary of the invention

[0008] Therefore, it may be desirable to provide an improved substrate handling apparatus which allows for better handling, in particular of thin substrates.

[0009] The problem of the invention is solved by the subject matter of the independent claims, wherein further embodiments are incorporated in the dependent claims.It should be noted that the aspects of the invention described below also apply to a substrate handling apparatus for wafers, a substrate handling system for wafers and a method for substrate handling.

[0010] According to the present invention, a substrate handling device for a wafer is provided. The substrate handling device comprises:

[0011] - End effector,

[0012] - straightening rings, and

[0013] -Suction cup.

[0014] The suction cup is arranged inside the straightening ring. A first portion of the suction cup can be connected to a vacuum supply via the end effector, and a second portion of the suction cup can be attached to a substrate by a reduced pressure provided by the vacuum supply. The suction cup protrudes from the straightening ring in a normal pressure state. The suction cup is at the same level as the straightening ring in a reduced pressure state, in which the substrate is held by the suction cup so that the straightening ring contacts the substrate.

[0015] The substrate handling device is configured to handle a substrate. The substrate to be handled may be a wafer. The substrate may be thin or ultra-thin, which should be understood as a substrate with a thickness from a few hundred micrometers to less than 100 micrometers, preferably 10 to 750 μm, and more preferably 20 to 100 μm. Substrates with this thickness are usually very fragile and initially already bent, possibly due to gravity, stresses inside the material or similar reasons. This means that thin substrates usually do not have a flat surface or do not form a flat surface when held without support.

[0016] The suction cup is arranged in the straightening ring. The suction cup may be arranged in the center of the straightening ring. The straightening ring may surround the suction cup. The straightening ring thereby constrains the suction cup. The straightening ring constrains or prevents (radial) deformation of the suction cup and does not allow the suction cup to deform according to a given bending state of the substrate. Thus, in the case of thin and generally non-planar substrates, the vacuum suction is not lost and such substrates are neither broken nor lost.

[0017] The straightening ring may be releasably attached to the end effector. The straightening ring may be removably or interchangeably connected to the end effector. In other words, the straightening ring may not be part of the end effector, integrated into the end effector, or integral with the end effector. The straightening ring may not be fixed or permanently connected to the end effector, but may be replaced or replaced with another straightening ring that is newer or has other properties, shapes or sizes. Additionally or alternatively, the suction cup may be releasably attached to the end effector.

[0018] In an embodiment, the straightening ring may be connected to the end effector directly or indirectly via a support element arranged between the end effector and the straightening ring. When mounted to the end effector or the support element, the straightening ring may provide a form fit, a force fit or a threaded connection, so that the straightening ring can be easily released, exchanged or replaced.

[0019] In an embodiment, the suction cup may be connected to the end effector directly or indirectly via a support element arranged between the end effector and the straightening ring. The suction cup may be connected to the end effector independently of the straightening ring, so that removal of the straightening ring does not affect the suction cup. When mounted to the end effector or the support element, the suction cup may provide a form fit, a force fit or a threaded connection, so that the suction cup can be easily released, exchanged or replaced.

[0020] During operation of the substrate handling apparatus, the first portion of the chuck is connected to the vacuum supply and the second portion of the chuck is sucked to the substrate or wafer.

[0021] In a normal pressure state or ambient pressure, the suction cup protrudes from the straightening ring. In particular, the substrate contact surface of the suction cup may protrude from the straightening ring. In other words, the outer edge of the suction cup may initially extend a distance further away from the end effector body than the straightening ring.

[0022] In the reduced pressure state provided by the vacuum supply, the suction cup is at the same level as the straightening ring. In other words, the outer edge of the suction cup can reach the same height as the straightening ring. In the reduced pressure state, the straightening ring can contact the substrate, a reduced pressure or vacuum can be applied to the substrate surface, and the suction cup can hold the substrate in the appropriate position. The straightening ring provides a specific contact area (specific area profile) with the substrate and thereby provides a means for straightening also bent and / or otherwise deformed substrates. As a result, the curvature of the substrate caused by the reduced pressure or vacuum and, if applicable, the initial or pre-existing curvature of the substrate can also be significantly reduced.

[0023] The substrate handling device for wafers according to the invention thus allows better handling of thin substrates. It significantly improves the performance and functionality of fragile substrate handling. The disc-shaped straightening ring is arranged around the suction cup, acting as a vacuum suction gasket. The straightening ring thus limits or prevents (radial) deformation of the suction cup and does not allow the suction cup to deform according to a given bending state of the substrate. Therefore, in the case of thin and generally non-planar substrates, the vacuum suction is not lost, and such substrates are neither broken nor lost. Thus, it is possible to safely move thin and / or curved substrates into and out of very small gaps (such as conveyor cassettes or specific processing chambers or equipment or the like) whose dimensions are close to the thickness of the substrate. In other words, thin and even warped, curved, bent and / or otherwise non-planar wafers / substrates can be handled, held, transferred and / or the like. Such substrates can be straightened or flattened during handling to allow movement also under reduced space requirements.

[0024] In an embodiment, the rate of protrusion or release of the suction cup from the straightening ring can be adjusted by controlling the pressure or vacuum applied in the suction cup so as to release the substrate from the suction cup in a controlled manner. Thus, the reduced pressure or vacuum can be gradually turned off or reduced. Thus, the substrate can be released at a predetermined point in time. The release of the suction cup from the straightening ring and thereby the substrate can be performed at all speeds from immediate to relatively slow. It can be a pop-up or it can be done carefully and smoothly. In some cases, the main advantage can be that the release of the substrate can be achieved with zero uncontrollable delay. There can also be an intentional delay of microseconds to seconds in releasing the substrate before the reduced pressure or vacuum is intentionally weakened enough to release the substrate. When the substrate is released again, the reduced pressure or vacuum can be turned off or gradually reduced. Thus, the suction cup is raised, moved, expanded back to its initial position and again extends a distance further away from the end effector body than the straightening ring. Thus, the substrate is pushed away from the straightening ring and can be released from the suction cup at a predetermined moment without any difficulty or release delay. In other words, the release of the substrate occurs instantaneously at a moment determined as required. Thus, substrate handling and substrate handling time are significantly improved, and the risk of wafer cracking caused by delayed substrate release is significantly eliminated.

[0025] In an embodiment, when the straightening ring contacts the substrate and the substrate is non-planar, the straightening ring at least partially straightens the non-planar substrate. The straightening ring may not only contact the substrate, but also carefully force the straightening of an initially bent or curved substrate. The straightening may depend on the vacuum strength and / or the size and / or shape of the straightening ring. In other words, the straightening effect on the curved substrate may be adjusted by the strength of the applied vacuum or reduced pressure and / or the size and / or shape of the straightening ring. In an embodiment, the suction cup may be retracted with the strength of the applied vacuum or reduced pressure. Thus, flattening of a curved substrate may be facilitated without damaging the (ultra) thin substrate.

[0026] The substrate may comprise a conductor plate, a semiconductor substrate, a thin film substrate, a substantially plate-shaped, metallic or metallized workpiece or the like. A vacuum or reduced pressure may be supplied to the substrate via the suction cup and preferably to the back side of the substrate. The back side of the substrate is the side of the substrate which has no structures, e.g. electronic components, or has smaller structures, if applicable. However, the front side of the substrate may also be contacted, the front side being the side with (more) structures or electronic components. The structures or electronic components may be protected from contact damage by, for example, a passivation layer deposited on top of the structures or electronic components. The vacuum outlet may be positioned below the straightening ring and preferably at a distance from the straightening ring.

[0027] The end effector may include a plurality of substrate handling surface contacts and utilize vacuum or reduced pressure to hold the substrate or wafer on the end effector. The intensity of the applied vacuum or reduced pressure may be adjusted based on the requirements of different substrates and their curved profiles. In addition, the shape, size and material of the straightening ring may be adjusted based on the requirements of different substrates and their curved profiles. The same is true for the suction cup.

[0028] The suction cup may be elastic, soft and / or flexible. It may be made of an elastic, soft and / or flexible material. It may be made of a material that does not contaminate the substrate. The suction cup may be made of silicone.

[0029] The straightening ring or disc may be implemented in an annular shape or in a non-annular shape, it may be circular, oval or square or any other shape that may provide a beneficial effect. The straightening ring may be hard, stiff and / or rigid. In an embodiment, the straightening ring is made of a material that is more rigid than the material of the suction cup. The straightening ring may be made of ceramic (e.g. SiC) or plastic (e.g. PEEK).

[0030] In an embodiment, the substrate handling device further comprises a plurality of suction cups. Preferably, the substrate handling device comprises two to twenty, and more preferably comprises two, three or four suction cups.

[0031] In an embodiment, the substrate handling device further comprises a plurality of straightening rings, each straightening ring surrounding one of the suction cups. Preferably, the substrate handling device comprises two to twenty, and more preferably comprises two, three or four straightening rings, each straightening ring surrounding one of the suction cups. The substrate handling device preferably comprises an equal number of suction cups and straightening rings.

[0032] In an embodiment, the suction cup can hold the substrate in a reduced pressure state at all positions or a few selected positions or an arbitrary position relative to the ground. Preferably, the substrate handling device and the suction cup can hold the substrate in the reduced pressure state in a substantially horizontal or vertical position. When the substrate and the substrate handling device are positioned in a horizontal extension direction, the substrate can be placed or on top of the suction cup of the substrate handling device. The substrate can also be mounted under the suction cup when the handling device is turned upside down to pick up the substrate from a position where the substrate has been previously placed. When the substrate and the substrate handling device are positioned in a vertical extension direction, such as in a storage or transport cassette, the substrate can be placed or placed parallel and vertically extending close to the suction cup. Due to the reduced pressure or vacuum, the suction cup can be attached to the substrate in a horizontal or vertical position and pull the substrate closer until the substrate touches the straightening ring.

[0033] In an embodiment, the outer circumference of the straightening ring is larger than the outer circumference of the suction cup. This can be understood as the straightening ring can extend radially above the suction cup.

[0034] In an embodiment, under normal pressure, the suction cup protrudes a certain distance from the straightening ring. The ratio of the distance to the size of the substrate may be in the range of 30:1 to 800:1, and preferably in the range of 100:1 to 600:1. In other words, under normal pressure, the suction cup may extend axially above the straightening ring. In contrast, under reduced pressure, the suction cup may be at the same level as the straightening ring.

[0035] According to the present invention, a substrate handling system for wafers is also proposed. The substrate handling system comprises a substrate handling device as described herein and a vacuum supply. The vacuum supply is connected to a first part of a chuck of the substrate handling device.

[0036] In an embodiment, the substrate handling system further comprises at least one replacement straightening ring to replace a straightening ring of the substrate handling device.

[0037] According to the present invention, a method for substrate handling is also provided. The substrate handling method comprises the following steps, not necessarily in this order:

[0038] a) Providing suction cups arranged within the straightening ring.

[0039] At least the straightening ring is releasably attached to an end effector. A first portion of the suction cup is connected to a vacuum supply via the end effector. The suction cup protrudes from the straightening ring under normal pressure.

[0040] b) Providing contact between the second portion of the chuck and the substrate.

[0041] c) providing a reduced pressure state by the vacuum supply so that the substrate is held by the chuck.

[0042] The suction cup is at the same level as the straightening ring in the decompressed state, so that the straightening ring contacts the substrate.

[0043] The straightening ring contacts the substrate in the reduced pressure state and may at least partially straighten the substrate if the substrate is non-planar.

[0044] In particular, the apparatus, system and method are suitable for the processing of structured semiconductor substrates, conductor plates and thin film substrates, but are also suitable for the processing of the entire surface of planar metal and metallized substrates. According to the invention, the apparatus, system and method can also be used to produce large-surface photovoltaic panels or large monitor panels for solar power generation.

[0045] It is to be understood that the system, device and method for substrate handling of wafers according to the independent claims have similar and / or identical preferred embodiments, in particular as defined in the dependent claims. It is to be further understood that a preferred embodiment of the invention may also be any combination of the dependent claims with the respective independent claim.

[0046] These and other aspects of the invention will be apparent from and will be elucidated with reference to the embodiments described hereinafter. BRIEF DESCRIPTION OF THE DRAWINGS

[0047] Exemplary embodiments of the present invention will be described below with reference to the accompanying drawings:

[0048] Figure 1 An embodiment of a substrate handling apparatus for wafers according to the present invention is schematically and exemplarily shown. DETAILED DESCRIPTION

[0049] Figure 1 An embodiment of a substrate handling device 10 for wafers according to the present invention is schematically and exemplarily shown. The substrate handling device 10 is configured to handle thin or ultra-thin substrates or wafers (not shown), which may have a thickness of about 20 μm to 500 μm. Substrates with such thickness are usually very fragile, initially already bent, and have no flat surface.

[0050] The substrate handling device 10 comprises:

[0051] - end effector 11,

[0052] - straightening ring 12, and

[0053] - Suction cup 13.

[0054] The end effector 11 includes a plurality of suction cups 13 (only one is shown) that contact the substrate and utilize vacuum or reduced pressure to hold the substrate on the suction cups 13 or the end effector 11 .

[0055] The straightening ring 12 is more rigid than the suction cup 13, which is softer and more elastic than the straightening ring 12. The straightening ring 12 is releasably attached to the end effector 11. The outer circumference of the straightening ring 12 is larger than the outer circumference of the suction cup 13. This can be understood as the straightening ring 12 extending radially above the suction cup 13.

[0056] The suction cup 13 is arranged inside the straightening ring 12 and in the center of the straightening ring 12. The straightening ring 12 surrounds the suction cup 13 and thereby constrains the suction cup 13. It limits or prevents radial deformation of the suction cup 13 and does not allow the suction cup 13, which acts as a gasket, to deform according to a given bending state of the thin substrate. Therefore, in the case of thin and generally non-planar substrates, the vacuum suction force is not lost, and such substrates are neither broken nor lost.

[0057] The first portion of the suction cup 13 is connected to a vacuum supply via a vacuum outlet 15 of the end effector 11, and the second portion of the suction cup 13 can be attached to the substrate by the reduced pressure provided by the vacuum supply. During operation of the substrate handling apparatus 10, the vacuum supply is activated and the second portion of the suction cup 13 is sucked to the substrate. Figure 1 In the embodiment shown in FIG. 1 , the substrate will lie horizontally extending on top of the suction cup 13 .

[0058] As shown, the suction cup 13 protrudes from the straightening ring 12 in a normal pressure state. In particular, the substrate contacting surface 14 or outer edge of the suction cup 13 protrudes axially from the straightening ring 12. It extends a distance further away from the end effector body than the straightening ring 12. The suction cup 13 will be at the same level as the straightening ring 12 in a decompressed state (not shown), where the straightening ring 12 contacts the substrate so that the substrate is held by the suction cup 13. The outer edge of the suction cup 13 will reach the same height as the straightening ring 12 and will thus straighten a potentially bent substrate.

[0059] When the substrate should be released, the reduced pressure or vacuum will be turned off or gradually reduced. As a result, the suction cup 13 will be raised back to its initial position and extend further away from the end effector body and the straightening ring 12 again. As a result, the substrate will be pushed away from the straightening ring and then released from the suction cup 13 at a predetermined moment.

[0060] The straightening ring 12 and the suction cup 13 are releasably, detachably and exchangeably attached to the end effector 11. They can be exchanged or replaced by another straightening ring 12 or suction cup 13 that is newer or has other properties, shapes or sizes.

[0061] It must be noted that embodiments of the invention are described with reference to different subject matters. In particular, some embodiments are described with reference to method type claims, while other embodiments are described with reference to apparatus type claims. However, one skilled in the art will appreciate from the above and below descriptions that, unless otherwise indicated, any combination of features belonging to one type of subject matter is considered to be disclosed herein as relating to different subject matters. However, all functions may be combined, thereby providing more synergistic effects than the simple addition of the functions.

[0062] Although the present invention has been illustrated and described in detail in the drawings and the foregoing description, such illustration and description should be considered illustrative or exemplary and non-restrictive. The present invention is not limited to the disclosed embodiments. Other variations to the disclosed embodiments may be understood and realized by those skilled in the art when practicing the claimed invention in light of a study of the drawings, the disclosure, and the appended claims.

[0063] In the claims, the word "comprising" does not exclude other elements or steps, and the indefinite article "a" or "an" does not exclude a plurality. A single processor or other unit may fulfill the functions of several items recited in the claims. The mere fact that certain measures are recited in mutually different dependent claims does not indicate that a combination of these measures cannot be used to advantage. Any reference signs in the claims should not be construed as limiting the scope.

Claims

1. A substrate handling device (10) for a wafer, comprising: - an end effector (11), - a straightening ring (12), and - a suction cup (13), wherein the suction cup (13) is arranged inside the straightening ring (12), and at least the straightening ring (12) is releasably attached to the end effector (11), wherein a first portion of the suction cup (13) is connectable to a vacuum supply via the end effector (11), and a second portion of the suction cup (13) is attachable to a substrate by a reduced pressure provided by the vacuum supply, wherein when the substrate is provided onto the suction cup (13), the second portion of the suction cup (13) is opposed to the end effector (11) to contact the substrate, wherein the suction cup (13) protrudes from the straightening ring (12) under normal pressure, and The suction cup (13) is at the same level as the straightening ring (12) under a reduced pressure state. Under the reduced pressure state, the substrate is held by the suction cup (13) so that the straightening ring (12) contacts the substrate.

2. The substrate handling device (10) according to claim 1, wherein the suction cup (13) is also releasably attached to the end effector (11).

3. The substrate handling device (10) according to claim 1 or 2, wherein the straightening ring (12) surrounds the suction cup (13) and limits radial deformation of the suction cup (13).

4. The substrate handling apparatus (10) according to claim 1 or 2, wherein the suction cup (13) holds the substrate in the decompressed state in a substantially horizontal or substantially vertical position relative to the ground.

5. The substrate handling apparatus (10) of claim 1 or 2, wherein when the straightening ring (12) contacts the substrate and the substrate is non-planar, the straightening ring (12) at least partially straightens the non-planar substrate.

6. A substrate handling device (10) according to claim 1 or 2, wherein under the normal pressure state, the suction cup (13) protrudes from the straightening ring (12) by a distance d, and wherein the ratio of the distance d to the size s of the substrate is in the range between 30:1 and 800:

1.

7. The substrate handling device (10) according to claim 1 or 2, wherein an outer circumference of the straightening ring (12) is larger than an outer circumference of the suction cup (13).

8. The substrate handling device (10) according to claim 1 or 2, wherein in the normal pressure state, the substrate contact surface (14) of the suction cup (13) protrudes from the straightening ring (12).

9. The substrate handling device (10) according to claim 1 or 2, wherein the straightening ring (12) is made of a material that is more rigid than a chuck material of the chuck (13).

10. The substrate handling device (10) according to claim 1 or 2, further comprising a plurality of suction cups (13), and preferably three suction cups (13).

11. The substrate handling device (10) according to claim 10, further comprising a plurality of straightening rings (12), and preferably three straightening rings (12), each straightening ring surrounding one of the chucks (13).

12. A substrate handling system for wafers, comprising a substrate handling device (10) according to any of the preceding claims and a vacuum supply connected to a first part of a chuck (13) of the substrate handling device (10).

13. The substrate handling system of claim 12, further comprising at least one replacement straightening ring to replace the straightening ring (12) of the substrate handling device (10).

14. A method for substrate handling comprising the steps of: - providing a suction cup (13) arranged in the straightening ring (12), wherein at least the straightening ring (12) is releasably attached to the end effector (11), wherein a first portion of the suction cup (13) is connected to a vacuum supply via the end effector (11), and wherein the suction cup (13) protrudes from the straightening ring (12) under normal pressure, - providing contact between a second portion of the suction cup (13) and a substrate, wherein when the substrate is provided on the suction cup (13), the second portion of the suction cup (13) is opposite to the end effector (11) to contact the substrate, and - providing a reduced pressure state by means of the vacuum supply so that the substrate is held by the suction cup (13), The suction cup (13) is at the same level as the straightening ring (12) in the decompression state, so that the straightening ring (12) contacts the substrate.

15. The method of claim 14, wherein the straightening ring (12) contacts the substrate and, in the event that the substrate is non-planar, at least partially straightens the substrate under the reduced pressure conditions.

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