Apparatus for removing coatings from rectangular substrates

Abstract

In an apparatus for removing a coating from an angular substrate (2) by means of a coating removal head (3.1, 3.2) and a moving device (5), it is required that the coating removal head (3.1, 3.2) can be guided in a working trajectory along the substrate longitudinal edge (4.1, 4.2, 4.3, 4.4) of the substrate (2).

Description

[Technical field]

[0001] The present invention relates to a device according to the preamble of claim 1 and to a method therefor.

[0002] Background technology Such devices are already known in a wide variety of forms and configurations and are commonly used, for example in DE 10 2012103330 A1 an apparatus for removing coatings from substrates is disclosed.

[0003] Substrates, such as wafers or boards, are coated for a variety of different uses or processing steps. In many cases, this coating is carried out over the entire surface of the substrate. However, in certain applications, it is necessary to leave the edge area of ​​the substrate free of coating. Usually, it is very laborious to coat only a portion of the substrate, and in a very uniform manner. Therefore, it is common to first coat the entire substrate and then remove the coating again in a predetermined edge area.

[0004] Removing a coating on a circular substrate is relatively simple: a nozzle is preferably directed at the edge area to be removed at a specific distance, and then the coating is removed using a solvent ejected through the nozzle while the substrate rotates under the nozzle. This is possible even when increased speed requirements are imposed during coating removal.

[0005] However, on angular substrates, such as rectangular, square or triangular substrates, it is nearly impossible to remove the coating at such high rates.

[0006] Furthermore, the coating on the substrate may consist of different layers that have different solubilities or may even only be removable by etching, and it is not possible to simply remove the different layers with just one nozzle.

[0007] Problem to be solved by the invention The object of the present invention is to overcome the drawbacks of the prior art. In particular, it is required to provide an apparatus that can quickly remove coatings from substrates of any shape, whereby in addition to saving time, it is required to achieve at least a constant quality of the coating removal, in the setting that it is required to be possible to remove the coating of a substrate in less than one minute and to be able to remove different resist and / or metal layers on the upper and / or lower side of the substrate.

[0008] Solution to the problem The problem is solved by the features stated in claims 1 and 10.

[0009] The device and method according to the invention for removing coatings from rectangular substrates are useful for removing so-called photoresist and / or metal from substrates in the field of photovoltaic or computer chip manufacturing. Both of these fields the device and method are not limited to, but are especially designed for these fields. By removing a coating from a substrate we mean removing the coating from the top and / or bottom surface of the substrate. The concept of coating removal also includes resist removal and other terms that mean removing a layer or resist or metal or the like.

[0010] In the device and method according to the invention, so-called coating removal heads with corresponding nozzles are used. The applied photoresist and / or applied metal, which needs to be removed in the edge area of ​​the substrate in order to be able to carry out further processing, are usually applied to the support plate in liquid form or, in the case of metals, by electroplating or deposition, and form a hard surface after a drying process. The solvents and / or etching media used in the coating removal heads are usually adapted to the coating to be removed.

[0011] The device according to the invention for removing coatings is required in particular for removing coatings from angular substrates and wafers that are not perfectly round (flat). Such substrates may have a size of, for example, 2000 mm x 2000 mm. However, other sizes are also conceivable. However, circular substrates can of course also be used in the invention. In the present invention, the device comprises a coating removal head and a movement device. By angular substrates is meant substrates that are not perfectly round. An angular substrate is also given when essentially rectangular substrates are present, for example with rounded and chamfered corner edges.

[0012] The coating removal head has a nozzle by means of which a solvent and / or etching medium is applied to the substrate at one working position. Each medium serves to remove the resist or metal, i.e. the coating, present on the substrate. In particular, it is required that the resist and / or metal is removed uniformly from the edge area of ​​the rectangular substrate.

[0013] Particularly preferably, the solvent and / or etching medium is ejected in a straight line or in the form of a jet. The use of a nozzle has the advantage that the width of the area to be removed can be defined by how close or far the nozzle is guided to the edge of the substrate, preferably within ±20 μm from the edge. It is furthermore advantageous that the removal of the coating is possible without damaging the substrate. It is furthermore advantageous that the coating can be completely removed by a suitable selection of the solvent and / or etching medium and the pressure of the jet.

[0014] In a typical embodiment, the nozzle is adapted to emit a medium jet such that it is guided within the nitrogen jet and then impinges on the coating to be removed, which has the advantage that the medium jet is highly stable and micro-sputtering is induced, which leads to a more precise removal of the coating areas on the substrate.

[0015] The coating removal head is guideable in a working trajectory along the substrate longitudinal edge of the substrate, in this context guideable means that the coating removal head is reciprocable in a first direction.

[0016] In the current prior art, the coating removal head is arranged statically, and the usually circular substrate is held to rotate under and / or above the coating removal head, so that the coating can be removed from the edge area of ​​the substrate. This method is meaningless when removing the coating from a square substrate, because this method always removes the coating only from the corner area, but not from the longitudinal edge of the substrate.

[0017] Further, a moving device is provided, and the moving device and the coating removal head are connected to each other in an OR circuit, and the moving device rotates the substrate so that the coating removal head is guided to work or another substrate longitudinal edge of the substrate is operatively connected to the working track of the coating removal head.

[0018] It may be specified that the moving device can also be actuated between the forward and retraction movements of the coating removal head. Thus, during the forward movement, the coating can be removed from a first substrate longitudinal edge. Then, when the moving device operatively connects another substrate longitudinal edge to the working track of the coating removal head, the retraction movement of the coating removal head can be used to remove the coating from another substrate longitudinal edge. However, depending on the resist and / or metal, it is also possible to end the reciprocating movement of the coating removal head before the moving device operatively connects another substrate longitudinal edge of the substrate to the working track of the coating removal head.

[0019] In order to further increase the efficiency, it is also possible for the device to be provided with further working tracks with further coating removal heads, which would be advantageous.

[0020] It is also advantageous for the coating removal head and the other coating removal head to operate simultaneously, so that opposing longitudinal edges of the substrate are equally and simultaneously loaded, which generally simplifies stabilization of the substrate and halves the time for substrate alignment.

[0021] Additionally, it may be specified that the coating removal head and the further coating removal head can be guided in the same direction or in the opposite direction to one another. In the same direction it is meant that both coating removal heads perform identical reciprocating movements parallel to one another. In the opposite direction it is meant that one coating removal head performs a forward movement while the other performs a backward movement. In such an arrangement, it is advantageous that structures in the device can be arranged in a space-saving manner. The supply lines of both coating removal heads, in the case of coating removal heads operating in opposite directions, have less risk of the supply lines interfering with one another in the narrow housing of the device.

[0022] Furthermore, a bracket may be provided on the device. The bracket is designed so that a gas outlet is provided. The gas outlet is designed as an air outlet or as an air outlet nozzle. In the working position, the bracket slides along the substrate from which the coating is to be removed on the side opposite the respective coating removal head. Thin substrates would be deformed if stabilization by the bracket is not provided on the opposite side. For this purpose, the bracket has a gas outlet. The gas outlet forms a stabilizing air flow. The gas outlet is thus an air outlet provided on the bracket and is designed to flow gas along the substrate on the side opposite the coating removal head and thus stabilize the substrate.

[0023] By thin it is meant that the substrate may have a thickness of less than 1 mm. Of course, the invention is not limited to a substrate having a thickness of less than 1 mm, since the substrate may have a thickness of several mm.

[0024] Moreover, it is also possible to use two or more nozzles in each coating removal head.This can advantageously reduce the working time for removing the coating from the substrate.Furthermore, different solvents, etching media, water and / or gases or gas mixtures can be discharged through different nozzles, which can dissolve, water-clean or dry different layers possibly present in the coating on the substrate in different ways.

[0025] In this case, the possibility of using different nozzles with different solvents and / or etching media for the reciprocating movement of the coating removal head should also be considered. For example, a first nozzle can dispense a first solvent / etching medium during the forward movement of the coating removal head, then another nozzle can dispense a different solvent / etching medium during the retraction movement, a third nozzle can dispense a third solvent / etching medium during a new forward movement of the coating removal head, etc. Of course, it should also be considered that all nozzles dispense different solvents / etching media only during the forward and / or retraction movement of the coating removal head. However, this does not seem to be very practical.

[0026] In a typical embodiment, the apparatus further comprises a suction device. This has the advantage that the solvent and / or etching medium splashing from the substrate does not reach the environment or the process environment, but can be sucked in, possibly treated and possibly reused. Another advantage of the suction device is that it can suck in the coating removed from the substrate, so that the coating does not reach the process environment. To this end, the suction device is preferably equipped with a hood. As a result, the hood serves as an additional protection against the solvent and / or etching medium and / or the dissolved coating splashing into the surroundings.

[0027] Furthermore, a sensor monitoring device is provided to ensure the quality of the work process.

[0028] Additionally, a method according to the invention for removing a coating from an angular substrate is claimed. The method likewise uses a coating removal head and a displacement device, the coating removal head being guided in a working track along the substrate longitudinal edge of the substrate, and the displacement device then operatively connects another substrate longitudinal edge of the substrate to the working track of the coating removal head. To this end, the coating removal head and the displacement device have an OR circuit, i.e. either the coating removal head is actuated or the displacement device is actuated. It is not excluded that the coating removal head performs the coating removal during the forward movement. The displacement device can then bring another substrate longitudinal edge of the substrate into the working track of the coating removal head by rotating the substrate by 90°. Then, further, the coating of the other substrate longitudinal edge is removed during the backward movement. This also allows, for example, a further increase in efficiency.

[0029] The method according to the invention can also use a further coating removal head which simultaneously processes a further substrate longitudinal edge of the substrate with a further working track to remove the coating, whereby it is advantageous if the coating removal head and the further coating removal head work simultaneously, i.e. the coating removal head runs on its working track and the further coating removal head runs on its own further working track.

[0030] Furthermore, the coating removal head and the further coating removal head are guided in the same direction or in the opposite direction to each other. In the same direction means that the coating removal head and the further coating removal head are moved in one direction, side by side, parallel to each other. In the opposite direction means, for example, that one coating removal head performs a forward movement, while at the same time the other coating removal head performs a backward movement. Simultaneously or at the same time means that within the scope of the invention, a slight time delay may also be included. A time delay in a barely perceptible time window can be considered as simultaneous or synchronous. The same applies if both coating removal heads run at different speeds and reach the start or end of their respective working paths at the same time.

[0031] It is likewise possible to carry out the removal of the coating of the substrate or the substrate edge on the upper and lower sides of the substrate either one after the other or simultaneously.

[0032] During the coating removal process or during the working process or in the working position, a bracket runs on the opposite side of the substrate, either physically connected to the respective coating removal head or running together with the coating removal head as part of the device independently of the coating removal head in the working position on the opposite side of the substrate, and always flows a gas or a gas mixture on one side along the part of the substrate longitudinal edge, which is exactly opposite the substrate and exactly processed by the coating removal head, relative to the plane of the coating removal head. This is advantageous because it stabilizes the area of ​​the substrate or the substrate longitudinal edge exactly where the coating is removed.

[0033] The present embodiment has been described assuming the use of one or two coating removal heads. However, it should be understood that the provision of more than two coating removal heads is within the scope of the present invention. For example, three or four coating removal heads or more than four coating removal heads may be provided for substrates with five or more longitudinal side edges. In such a configuration, the coating removal heads must be switched so as not to interfere with each other with respect to their reciprocating motion.

[0034] Furthermore, the invention requires that edge coating removal is possible, especially from rectangular substrates with ABF coatings (Ajinomoto Build-Up Film) or other resin-like coatings. For this purpose, for example, a rectangular substrate with an ABF coating is provided. This substrate is bonded with a plastic film (for ABF made of PET), which covers the coating almost completely. On the outside of the film, typically a few mm of edges are free of film and are not covered by it. For example, by bonding the film to the area coated with ABF, a part of the ABF is pressed outwards and thus bulges under the film. This excess coating material must be removed.

[0035] The following process steps serve to remove this residual coating at the edges: - Soften the coating by applying a solvent (e.g. MEK = methyl ethyl ketone: butanone in the case of ABF) at low pressure. After the softening stage, the dissolved but still slimy and sticky coating material can be removed by a high-pressure jet from a fan nozzle, so that only the coating remains underneath the film.

[0036] In this method, a low-pressure nozzle and a high-pressure nozzle are combined in one nozzle head. In a first step, only the low-pressure nozzle is switched on and a solvent is applied for dissolution. Then, after a waiting time of about 15 seconds (for ABF), the coating is removed with a second throughput using the high-pressure fan nozzle. Depending on the coating material and layer thickness, the action time can be varied. This method also allows for simultaneous removal of the coating on the top and bottom side of the substrate.

[0037] Further advantages, features and details of the invention will become apparent from the following description of preferred embodiments taken in conjunction with the drawings. [Brief description of the drawings]

[0038] [Figure 1] FIG. 1 is a schematic plan view of an apparatus for removing a coating from a rectangular substrate. [Diagram 2] FIG. 2 is a schematic side view of the device shown in FIG. 1.

[0039] Working Example 1 and 2 show an apparatus 1 for removing a coating from an angular substrate 2. Coating removal involves the removal of a coating, in particular photoresist and / or metal, from the surface of the substrate 2, in this embodiment in particular from the edge region 12 of the substrate 2.

[0040] Examples of possible substrates are square wafers, rectangular wafers, polygonal wafers, thin film plates, boards or the like.

[0041] The device 1 has in this embodiment two coating removal heads 3.1, 3.2, both of which can be guided along the substrate longitudinal edge 4.1; 4.2 of the substrate 2 in the respective working trajectories along the arrows 10, 11. That is to say, the coating removal heads 3.1, 3.2 can be moved along the arrows 10, 11 in the X-direction and in the Y-direction. However, it may also be preferred if a moveability of the coating removal heads 3.1, 3.2 in the Z-direction is provided. In this way, the distance between the coating removal heads 3.1; 3.2 and the surface of the substrate 2 can be adjusted, but also the distance between the coating removal heads 3.1; 3.2 and the respective substrate longitudinal edge 4.1; 4.2 can be adjusted. The adjustability or moveability of the coating removal heads 3.1, 3.2 is effected by an adjustment device (not shown).

[0042] The apparatus 1 further comprises a movement device 5 for holding, positioning and / or aligning the substrate 2. The movement device 5 is shown in dashed lines in Fig. 1. The movement device 5 in this embodiment is capable of rotating the substrate 2 by 90° in the direction of the arrow 6, so that another substrate longitudinal edge 4.3; 4.4 of the substrate 2 can be operatively connected to the working tracks of the coating removal heads 3.1; 3.2.

[0043] The coating removal heads 3.1; 3.2 and the movement device 5 have an OR circuit (not shown) by which the coating removal heads 3.1, 3.2 are guided in their working trajectories along the longitudinal edges 4.1; 4.2 or 4.3; 4.4 of the substrate or the movement device 5 rotates the substrate 2, so that the individual elements do not interfere with each other.

[0044] Furthermore, both coating removal heads 3.1, 3.2 preferably act in opposite directions. However, within the scope of the invention, a movement of both coating removal heads 3.1, 3.2 in the same direction may also be included. However, such a movement is only possible if the substrate 2 is large enough that there remains sufficient space for each coating removal head 3.1, 3.2 along each substrate longitudinal edge.

[0045] The device 1 further comprises a bracket 7, which in the working position is arranged on the opposite side of the substrate 2 from the coating removal heads 3.1; 3.2. The bracket 7 is provided with a gas extrusion 8 for the substrate 2. A stabilizing air flow is delivered to the substrate 2 via the gas extrusion 8. The substrate 2 is usually very thin (less than 1 mm at most), so that if the substrate has a large surface area, it may bend or sag downwards during the treatment. This would result in unevenness in the area from which the coating is to be removed. To prevent this, a stabilizing air flow is delivered to the substrate 2 via the gas extrusion 8. The stabilizing air flow is thereby delivered to the substrate 2 via the gas extrusion 8 along the opposite side of the substrate 2 from the coating removal heads 3.1; 3.2, which in turn stabilizes and pulls the substrate 2 flat, so that a uniform coating removal of the substrate 2 can be achieved.

[0046] For coating removal, each coating removal head 3.1, 3.2 has two or more nozzles 9, preferably five to six nozzles 9.

[0047] Furthermore, the device 1 comprises a sensor monitoring device (not shown), preferably a quality assurance sensor monitoring device.

[0048] The function of the device according to the invention will now be explained with reference to FIGS.

[0049] The substrate 2 from which the coating is to be removed is placed on the transfer device 5 and held via suction cups (not shown). The two coating removal heads 3.1, 3.2 are positioned at the two opposite longitudinal edges 4.1, 4.2 of the substrate at a predetermined distance from the longitudinal edges 4.1; 4.2, i.e. the two coating removal heads 3.1, 3.2 are arranged diagonally from one another on the one hand. On the other hand, the nozzles 9 of the coating removal heads 3.1, 3.2 must be arranged at a predetermined distance from the surface of the substrate 2, in particular from the regions of the substrate 2 from which the coating is to be removed.

[0050] At the same time, the bracket 7 with the gas extrusion 8 is positioned at a small distance below the substrate or on the opposite side of the substrate 2 from the coating removal heads 3.1, 3.2. This is done so that the stabilizing air flow can flow directly from the gas extrusion 8 to the opposite areas to be stabilized in the edge region 12 of the substrate 2. Through the small gap between the gas extrusion 8 and the substrate 2, the air flows very quickly. The static pressure between both elements is reduced. As a result, less pressure acts on the underside of the substrate 2 than on the upper side. The substrate 2 is therefore pressed downwards by the greater ambient pressure on the upper side.

[0051] Once the substrate 2 has been positioned on the moving device 5 and the coating removal heads 3.1, 3.2 have been positioned at the substrate longitudinal edges 4.1, 4.2, the coating removal heads 3.1, 3.2 are run along the substrate longitudinal edges 4.1, 4.2 in their working trajectory, i.e. in opposite directions in this embodiment, i.e. towards the distal ends of the respective substrate longitudinal edges 4.1; 4.2 as shown in relation to FIG. 1.

[0052] While the coating removal heads 3.1, 3.2 are guided in their working path along the substrate longitudinal edges 4.1, 4.2, the brackets 7, including the gas pushers 8, are also guided uniformly under the substrate 2, so that a flow along the substrate 2 can be generated and thus the substrate 2 can be kept uniformly flat during the coating removal process. If the substrate 2 is tilted or curved, the coating cannot be removed uniformly and in the desired area. Furthermore, curved substrates are also problematic, since in some cases too much or too little material can be removed from the substrate. This means that the leveling of the substrate 2 is performed simultaneously with the running of the coating removal heads 3.1, 3.2 along the substrate longitudinal edges 4.1, 4.2 and, as a result, simultaneously with the coating removal.

[0053] Furthermore, while the coating removal heads 3.1, 3.2 are run along the longitudinal edge 4.1, 4.2 of the substrate in their working trajectory, one or more solvents and / or etching media are sprayed via the nozzle 9 depending on the structure of the coating present on the substrate surface. For this purpose, the nozzle 9 is connected to a medium pump (not shown) and a solvent or etching medium reservoir (not shown). The medium pump is suitable for discharging the solvent and / or etching medium under (low) pressure. At the same time, the solvent and / or etching medium is also preferably discharged straight or in the form of a jet. For this purpose, the nozzle 9 is preferably connected to a compressed air or nitrogen source (not shown). In order to be able to discharge the solvent and / or etching medium and the compressed air / nitrogen jet, the nozzle 9 may have two discharge tubes (not shown) guided inside each other. Preferably, the solvent and / or etching medium is discharged straight or in the form of a jet under pressure from the inner tube. A compressed air or nitrogen jet is then discharged from the outer tube. Thus, the coating is dissolved and removed along the longitudinal edges 4.1, 4.2 of the substrate.

[0054] The medium may be any suitable solvent, an etching medium or small particles having an abrasive action.

[0055] The coating removed by the solvent and / or etching medium and / or the solvent and / or etching medium itself must be directed away from the substrate 2 in order to prevent damage to the substrate 2. For this purpose, a suction device 13 with a hood (not shown) is provided, which is connected to a negative pressure source (not shown) via a line (not shown). The hood serves as an additional protection device to prevent the solvent and / or etching medium from splashing into the surroundings.

[0056] When the coating removal heads 3.1, 3.2 reach the distal end of each of the substrate longitudinal edges 4.1; 4.2 and have completed the coating removal process for these substrate longitudinal edges 4.1, 4.2, the coating removal heads 3.1, 3.2 are returned to their starting position in the working track. The moving device 5 then rotates the substrate 2 by 90° and operatively connects another substrate longitudinal edge 4.3, 4.4 of the substrate 2 to another working track of another coating removal head, and the above-mentioned process is repeated. Depending on the OR circuit, the coating removal heads 3.1, 3.2 or the moving device 5 are activated. These above-mentioned steps are repeated until all desired edges and / or sides of the substrate 2 have been processed and completely or at least to the desired level decoated.

[0057] While only one preferred embodiment of the invention has been described and illustrated, it will be appreciated that numerous modifications can be made by one skilled in the art without departing from the spirit and scope of the invention. [Explanation of symbols]

[0058] 1 device 2. Board 3 Coating removal head 4. Longitudinal edge of board 5. Mobile Devices 6 Arrows 7 Bracket 8 Gas Extrusion Section 9 Nozzles 10 Arrows 11 Arrow 12 Edge Region 13 Suction device

Claims

1. In an apparatus for removing a coating from a rectangular substrate (2) by means of a coating removal head (3.1, 3.2) and a moving device (5), the coating removal head (3.1, 3.2) is characterized in that it can be guided along a working path along the longitudinal edges (4.1, 4.2, 4.3, 4.4) of the substrate (2) in the longitudinal direction of the substrate, the apparatus.

2. The moving device (5) operatively connects another longitudinal edge (4.1, 4.2, 4.3, 4.4) of the substrate (2) to the working path of the coating removal head (3.1, 3.2), and the coating removal head (3.1, 3.2) and the moving device (5) have an OR circuit, the apparatus according to claim 1.

3. The apparatus according to claim 1 or 2, characterized in that another working path with another coating removal head (3.1, 3.2) is provided.

4. The apparatus according to claim 1 or 2, characterized in that the coating removal head (3.1, 3.2) and another coating removal head (3.1, 3.2) can be guided in the same direction or in opposite directions with respect to each other.

5. The apparatus according to claim 1 or 2, characterized in that a bracket (7) is provided, and the bracket (7) has a gas extrusion part (8).

6. The apparatus according to claim 5, characterized in that the bracket (7) is arranged on the side of the substrate (2) opposite to the coating removal head (3.1, 3.2) in the working position.

7. The apparatus according to claim 5, characterized in that the bracket (7) has the gas extrusion part (8) for a stabilizing air flow, and the gas extrusion part (8) is configured such that gas flows along the substrate (2) on the side opposite to the coating removal head (3.1, 3.2).

8. The apparatus according to claim 1 or 2, characterized in that each coating removal head (3.1, 3.2) has two or more nozzles (9).

9. The apparatus according to claim 1 or 2, characterized in that a sensor monitoring device is provided.

10. In a method for removing a coating from a rectangular substrate by means of a coating removal head (3.1, 3.2) and a moving device (5), A method, characterized in that the coating removal head (3.1, 3.2) is moved along a working track along the longitudinal edges (4.1, 4.2, 4.3, 4.4) of the substrate (2).

11. The method according to claim 10, characterized in that the moving device (5) operatively connects another longitudinal edge (4.1, 4.2, 4.3, 4.4) of the substrate (2) to the working track of the coating removal head (3.1, 3.2), and the coating removal head (3.1, 3.2) and the moving device (5) are connected via an OR circuit.

12. The method according to claim 10 or 11, characterized in that another longitudinal edge (4.1, 4.2, 4.3, 4.4) of the substrate (2) is operatively connected to another working track of another coating removal head (3.1, 3.2).

13. The method according to claim 12, characterized in that the coating removal head (3.1, 3.2) and the other coating removal head (3.1, 3.2) are guided in the same direction or in opposite directions to each other.

14. The method according to claim 10, characterized in that a stabilizing air flow of the gas extrusion part (8) of the bracket (7) is flowed along the substrate (2) on the side opposite to the coating removal head (3.1, 3.2) to stabilize the substrate (2).

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