Drying device for a semiconductor wafer

Abstract

The invention relates to a drying device which is designed to dry at least one wetted semiconductor wafer (200), which is temporarily arranged in said device on a carrier unit (10), during at least one drying process, wherein the drying device (100) comprises a drying hood unit (110). The drying hood unit (110) comprises at least one transparent pane element (111, 112, 113) which is designed and arranged on the drying hood unit (110) such that, when the drying hood unit (110) is in the closed state, the pane element provides a substantially unrestricted optical view of substantially the entire surface of the arranged semiconductor wafer (200), in particular for at least one operator, when viewed from outside the drying device (100) via the at least one transparent pane element (111, 112, 113), throughout the entire at least one drying process.

Description

[0001] Drying device for a semiconductor wafer

[0002] Technical area

[0003] The invention relates to a drying device for a semiconductor wafer and a method for drying a semiconductor wafer within the drying device.

[0004] State of the art and technical task

[0005] In known drying processes or drying devices for wetted semiconductor wafers that have previously undergone a cleaning step, drying usually takes place within a drying device arranged at the end of a cleaning line and formed with a housing made at least predominantly of plastic or stainless steel. After drying, it is then usually provided that each semiconductor wafer, along with other semiconductor wafers of a predefined quantity that have undergone the drying process (serially or in parallel), is mechanically deposited in a cassette unit temporarily docked to the drying device. This cassette unit, in turn, is then usually transferred mechanically or manually to a subsequent process step (e.g., analysis station) for the semiconductor wafer(s) of the predefined quantity.

[0006] At this point in time, however, the operator has no information as to whether the process control or the process parameters on the drying device were actually set correctly and adapted to the specific requirements for the wetted semiconductor wafers to be dried, in other words, whether the set process parameters led to completely dried semiconductor wafer surfaces (in other words, without undried^) area(s) on the surface) of the semiconductor wafers during the drying process.

[0007] It is known that the drying process for wetted semiconductor wafers following a cleaning step within the drying devices provided for this purpose can result in inconsistent or incomplete drying processes of the semiconductor wafer.

[0008] This manifests itself negatively in one or more remaining, unsuccessfully dried areas (hereinafter referred to as non-dried areas) on the surface of the semiconductor wafer, visible to the naked eye. There are many reasons for this. Among other things, the non-dried area can be a result of:

[0009] - Clogged holes of an IPA spray bar of the drying device,

[0010] - Change in the supply and exhaust air conditions of the drying device,

[0011] - Changes in differential pressures between different areas of the drying system, etc.

[0012] As described above, such errors can only be made accessible to the operator at a later point in time at another process station visually or by means of suitable measuring methods (particularly in a separate inspection station), if such analyses are provided at all.

[0013] Even if a downstream inspection station is provided, a drying quality analysis of the semiconductor surfaces can result in particles being deposited on the surface of the semiconductor wafer due to additional handling processes in the inspection station. These particles then have to be removed by a further cleaning step (followed by another drying step), which in turn is detrimental to the entire production chain in terms of time (and therefore cost). Furthermore, in this state of analysis or assessment of the semiconductor wafer, many parameters relevant to drying are inevitably not within the actual process window of the completely closed drying device. In order to readjust these parameters relevant to drying and establish a stable drying process, it is necessary to temporarily remove part of the drying device (the drying hood unit).This is the only way to directly observe the drying process. However, in this dryer state, the parameters relevant for drying do not correspond to those of a closed system. Therefore, this approach may only lead to the desired drying result (a previously successfully cleaned semiconductor wafer) after several attempts.

[0014] The present invention is therefore based on the objective, technical problem of providing a drying method and a drying device for a previously cleaned (and accordingly wetted) semiconductor wafer in a simple manner, which drying method and drying device do not have the above-mentioned disadvantages or at least have them to a lesser extent and which, in particular, do not result in any time losses for the manufacturing process and without any quality losses for the semiconductor wafer.

[0015] The object is achieved by a drying device with a drying hood unit according to claim 1, as well as by a method for drying a semiconductor wafer according to claim 9.

[0016] Description of the invention

[0017] The invention is based on the technical teaching or the invention has recognized that the time losses in the drying process and qualitative losses of the semiconductor wafer just described can be easily overcome by providing a drying device during the drying process which, instead of the conventionally provided drying hood unit in the form of an opaque dryer hood (e.g. made of stainless steel), provides a drying hood unit with at least one integrated, transparent pane element which allows or provides an optical inspection by the operator (or another person commissioned for the inspection as the operator) directly during the actual drying process.In other words, the invention has recognized that by providing said at least one transparent pane element at corresponding locations on the drying hood unit, the time of the drying process during which the semiconductor wafer is in the closed device can be used for this purpose, and the predetermined drying time (e.g. in the range of 20 s to 120 s for a single-wafer process, for temporally parallel processes (batch processes; e.g. 50 semiconductor wafers per batch up to approx. 12 min) is sufficient to simultaneously optically inspect the progress of the drying through the at least one transparent pane element and to detect residues of non-dried areas (which are an indication of incorrect, current process control) without the semiconductor wafer even having to be removed from the drying device, i.e. the semiconductor wafer remains under real process conditions during the inspection.If necessary, the operator can then intervene immediately to correct the drying process, i.e. in particular by changing the process parameters (such as printing parameters, printing cascade, concentration gradient, speed of the semiconductor wafer during the drying process, acceleration of the semiconductor wafer during the drying process) and in particular by adjusting the drying process to ensure successful drying of at least one next semiconductor wafer in the subsequent drying process and / or to make a change in the sense of extending the current drying time of the current drying process in order to, if necessary, directly contribute to successful drying quality of the semiconductor wafer(s) currently to be dried within the drying device.With the drying device according to the invention in conjunction with the drying method according to the invention, a faster and more effective readjustment of suitable process parameters under real process conditions can be enabled in the event of drying problems, which is initiated in response to the enabled simultaneous optical inspection of the semiconductor wafer(s) through the at least one transparent wafer element.

[0018] Furthermore, the particle performance can be improved by using the method according to the invention on the drying device according to the invention.

[0019] In addition, non-dried areas in geometry measurement methods generate measurement artifacts that lead to incorrect conclusions regarding the geometric properties of the semiconductor wafer. This, in turn, leads to problems with the adjustment of process parameters that influence the semiconductor wafer geometry during polishing. By avoiding both effects, it is possible to minimize failures and increase wafer yield.

[0020] The invention has particularly recognized that when using the provided drying hood unit with at least one transparent pane element, the regular drying time (as provided in conventional drying processes with conventional, opaque drying hood units) is sufficient to enable inspection on both sides of the semiconductor wafer.For this purpose, the distances between the positioned semiconductor wafer and the drying wafer unit, in particular with respect to the at least one transparent wafer element, are preferably kept comparatively small, and the wafer element (or wafer elements) are preferably arranged such that, viewed over the entire drying process, all sections of the semiconductor wafer that are essential for inspection, in particular essentially the entire semiconductor wafer, are visible and thus inspectable (this complete visibility is made possible in particular by the interaction of the at least one transparent wafer element with the conventional, guided movements of the semiconductor wafer within the drying device). Thanks to the interaction of the internal process control and the arrangement of the transparent wafer elements, a single person is sufficient for the complete inspection during the drying process.

[0021] A further advantage of the invention is that the basic structural internal design of the drying device does not have to be changed, but only the drying hood unit according to the invention has to be provided on it, so that the advantages for the process control and the desired drying quality of the semiconductor wafers can be realized by one operator.

[0022] According to a first aspect, the invention therefore relates to a drying device which is designed to dry at least one wetted semiconductor wafer temporarily arranged therein on a carrier unit during at least one drying process, in particular by utilizing the Marangoni effect, wherein the drying device comprises a drying hood unit. The drying hood unit comprises at least one transparent pane element which is designed and arranged on the drying hood unit in such a way that, in a closed state of the drying hood unit (orin a closed state of the drying device) from outside the drying device via the at least one disk element, viewed over the entire at least one drying process, provides a substantially unrestricted optical view of substantially the entire surface of the arranged semiconductor wafer, in particular for at least one operator.

[0023] In this way, the disadvantages of the prior art described above can be completely overcome and the advantages described above in connection with the invention can be achieved fully and in a simple manner.

[0024] The drying device according to the invention with the drying hood unit according to the invention is preferably suitable for a drying process utilizing the known Marangoni effect. However, it is also possible to use the drying hood unit according to the invention for an HF / O3 drying process, particularly if the drying hood unit is designed as a plastic frame structure with at least one transparent pane element.

[0025] In preferred variants, the drying device is preferably designed such that during a drying process more than one semiconductor wafer is arranged in the drying device at the same time (in particular using a bath system for several, e.g. up to 50 semiconductor wafers).

[0026] Preferably, the drying hood unit is designed to be in a closed state on the drying device during at least one drying process of a semiconductor wafer arranged within the drying hood device, wherein the drying hood unit can further be designed to enable an open state which, for example, allows adjustment of the components or of the at least one semiconductor wafer, or removal of the semiconductor wafer(s) or maintenance of the internal components of the device.

[0027] In preferred variants, the drying hood unit can be substantially thin-walled and / or shell-shaped and the at least one transparent pane element can be integrated into the shell, in particular integrated into a shell part of a hood of the drying hood unit.

[0028] In principle, the shape of the drying hood unit can be designed as desired, as long as it fulfills the function required to achieve the advantages described above in connection with the invention. However, in further preferred variants, it is preferably provided that the drying hood unit comprises a hood which, viewed in cross-section along its longitudinal axis, essentially describes the geometric shape of an ellipse segment, in particular a quarter ellipse. The hood can comprise at least two transparent pane elements, which can be arranged on hood segments with different geometric orientations.Such a geometric design for the drying hood unit is particularly advantageous because it is optimally adapted to the guided movement of the at least one semiconductor wafer across the carrier unit within the drying device during the drying process (translational movement and pivoting movement along the longitudinal axis), thus providing a small distance between the semiconductor wafer and the "cover surface" of the drying hood unit. If this "cover surface" is designed as a transparent pane element, a small distance is particularly useful for the optical inspection of the at least one semiconductor wafer (or facilitates the inspection).

[0029] In further preferred variants, essentially the entire drying hood unit can be designed as a hood.

[0030] In further preferred variants, the hood may comprise at least four hood segments, wherein

[0031] (i) a first hood segment, which may essentially have the shape of an elliptical cylinder shell section and may be designed as a kind of cover surface of the hood, and

[0032] (ii) a second hood segment, which may substantially have the shape of a rectangle and may close the hood on the side of the raised edge of the first hood segment, and (iii) a third and a fourth hood segment may each substantially have the shape of an ellipse section, in particular a quarter ellipse, wherein preferably a transparent pane element is integrated in at least two of the at least four hood segments.

[0033] In further preferred variants, the hood can be constructed in a frame-like manner, at least partially or across all hood segments. The frame structure is preferably formed from an electrically conductive material, and the at least one transparent pane element of the hood is formed from an electrically conductive material, in particular ESD antistatic polycarbonate.

[0034] In further preferred variants, the first hood segment can be designed in a frame-like manner, in particular from stainless steel or plastic, and a first, transparent pane element, in particular designed as an electrically conductive transparent material, for example polycarbonate ESD antistatic, can be arranged therein, and the second hood segment can be designed in a frame-like manner, in particular from stainless steel or plastic, and a second, transparent pane element, in particular designed as an electrically conductive transparent material, for example polycarbonate ESD antistatic, can be arranged therein.Furthermore, in this preferred variant, the third hood segment can be designed like a frame, in particular from stainless steel or plastic, and a third, transparent pane element, in particular designed as an electrically conductive transparent material, for example ESD antistatic polycarbonate, can be arranged therein, and the fourth hood segment can be designed over its entire surface, in particular from stainless steel or plastic. Alternatively, the fourth hood segment can be designed like a frame, in particular from stainless steel or plastic, and a fourth, transparent pane element, in particular designed as an electrically conductive transparent material, for example ESD antistatic polycarbonate, can be arranged therein, and the third hood segment, in contrast, can be designed over its entire surface, in particular from stainless steel or plastic.

[0035] A particularly simple to manufacture, but effective for the need for sufficient optical insight, design is therefore preferably provided with three transparent pane elements, in particular with a combination of three transparent pane elements from the first, second and third transparent pane elements described above or the first, second and fourth transparent pane elements described above.

[0036] In further preferred variants, the geometry of the drying hood unit can be designed such that the clear distances between the semiconductor wafer positioned on the carrier unit within the drying device and at least two transparent wafer elements are kept small.

[0037] Furthermore, the at least two transparent pane elements of the hood can be arranged on differently geometrically aligned hood segments, so that in a simple manner from outside the operator can visually inspect the entire drying process for all sections of the semiconductor wafer that are essential for the inspection, in particular essentially the entire semiconductor wafer, which performs a guided movement via the carrier unit within the drying device during the at least one drying process.

[0038] In further preferred variants, the at least one transparent

[0039] The pane element can be made of plastic or plexiglass.

[0040] In further preferred variants, the at least one transparent

[0041] The pane element may be made of electrically conductive material, in particular ESD antistatic polycarbonate. Additionally or alternatively, substantially the entire drying hood unit may be constructed from the at least one transparent pane element, which may be made of electrically conductive material, in particular ESD antistatic polycarbonate.

[0042] In further preferred variants, the at least one transparent pane element can be tightly fixed, and in particular releasably fixed, to the drying hood unit, in particular to a frame-like segment of a hood of the drying hood unit. Additionally or alternatively, the drying hood unit, in particular a hood of the drying hood unit, can be at least partially constructed in a frame-like manner, wherein this frame structure can be made of an electrically conductive material.

[0043] In further preferred variants, the at least one transparent pane element can be arranged within an associated, frame-like hood segment of a hood of the drying hood unit and form a monolithic unit with the associated, frame-like hood segment.

[0044] According to a second aspect, the invention relates to a method for drying a semiconductor wafer within the drying device according to the invention (or in combination with one or more of its advantageous variants) after the semiconductor wafer has undergone at least one cleaning step, wherein

[0045] • during at least one drying process, the surface of the at least one wetted semiconductor wafer, in particular substantially the entire surface, is dried, in particular by utilising the Marangoni effect, and

[0046] • during the at least one drying process, the drying progress and the drying quality are visually inspected by at least one operator via an optical inspection of the drying device from outside the drying device via the at least one transparent pane element.

[0047] In this way, the disadvantages of the prior art described above can be completely overcome and the advantages described above in connection with the invention can be achieved fully and in a simple manner.

[0048] In advantageous variants, a predeterminable drying time can be assigned to the at least one drying process, wherein the predeterminable drying time substantially corresponds to the predeterminable drying time of a comparison drying process during which the at least one semiconductor wafer is dried in a drying device with an opaque drying hood unit. If, for example, an operator has not identified any non-dried areas on the surface of the at least one semiconductor wafer during the inspection during the drying process, the drying time substantially corresponds to the drying time of a comparison drying process during which a semiconductor wafer is dried in a drying device with an opaque drying hood unit; however, the drying process has a longer drying time than known processes orComparison processes (POR) have the advantage that, through the simultaneous assessment of the drying progress and the drying quality directly during the drying process, essentially all drying-related inspection processes after the removal of the semiconductor wafer are eliminated and thus, in absolute terms, manufacturing time per semiconductor wafer can be saved for the entire manufacturing process of the semiconductor wafer.

[0049] In advantageous variants, a final inspection and final assessment of the drying progress and the drying quality, in particular of the assessment of whether at least one non-dried area has remained on the surface of the at least one semiconductor wafer at the latest upon expiration of the predetermined drying time, can be carried out exclusively in a closed state of the drying hood unit (or in a closed state of the drying device) with the semiconductor wafer arranged therein in the carrier unit via the optical inspection, in particular by the at least one operator, from the outside via the at least one transparent pane element.

[0050] In further advantageous variants, the operator can change locally between at least two positions during the drying process in order to inspect the substantially complete surface of the semiconductor wafer in order to inspect at least two different, in particular three, transparent wafer elements.

[0051] As described in detail above, the drying device according to the invention offers the advantage that, thanks to the at least one transparent pane element on the drying hood unit, the operator obtains unrestricted insight into the surfaces of the at least one semiconductor wafer during the drying process and, based on this insight, the operator can make an assessment of the drying quality and the drying progress.

[0052] Depending on the result of his assessment, different reaction scenarios may be available to the operator.

[0053] If the operator finds no non-dried areas or non-dried areas below a predeterminable tolerance threshold on the at least one semiconductor wafer, the drying process on the drying device is successfully completed at this stage for this at least one semiconductor wafer and it can then be transferred to the next process station by means of the cassette unit.

[0054] If, however, the operator detects at least one non-dried area (in particular above a predeterminable tolerance threshold) on the at least one semiconductor wafer, he can intervene essentially immediately by adjusting at least one process parameter on the drying device in order to provide stable process conditions for the subsequent drying processes for the semiconductor wafers introduced subsequently, leading to completely dried semiconductor wafers, for the further process sequence.

[0055] For this purpose, at least one of the following process parameters can be changed on the drying device: printing parameters, printing cascade, concentration gradient, speed of the semiconductor wafer during the drying process, acceleration of the semiconductor wafer during the drying process.

[0056] Preferably, after completion of the at least one drying process, the at least one semiconductor wafer is then arranged in the cassette unit temporarily docked to the drying device and, after at least partial filling of this cassette unit, the cassette unit is transferred to the next process station, manually or mechanically.

[0057] (i) In this case, the adjustment of at least one process parameter can comprise the step of the operator extending the predetermined drying time of the current drying process by an extension period via a setting on the drying device or starting a further drying process for the currently at least one semiconductor wafer if the assessment of the optical shape of the at least one non-dried region on the at least one semiconductor wafer during the drying process by the operator via the optical inspection via the at least one transparent wafer element is such that a temporal extension of the current drying process, in particular by a value in a range of 1 s to 60 s, is to be expected by direct intervention,that the at least one non-dried region on the at least one semiconductor wafer is substantially completely removed by the drying process at the latest upon expiration of the extension period.

[0058] (ii) In addition or alternatively to (i), the at least one semiconductor wafer within the cassette unit can be fed as the next process station to a renewed cleaning step on the cleaning line upstream of the drying device in the form of the next process station if the prior assessment by the operator at the drying device for this at least one semiconductor wafer via the optical inspection via the at least one transparent wafer element revealed that the optical shape of the at least one non-dried region on the at least one semiconductor wafer during the drying process or during the drying process extended by an extension period is so pronounced that a renewed cleaning step with a subsequent renewed drying process within the drying device is necessary.

[0059] Short description of the figure

[0060] Figure 1 shows a schematic three-dimensional representation of a drying device 100 according to the invention with a semiconductor wafer 200 with a drying hood unit 110 according to the invention with three transparent wafer elements 111, 112, 113 for complete inspection of the surface of the semiconductor wafer 200 during the drying process by an operator.

[0061] Preferred embodiment of the device according to the invention and of the method according to the invention In the following and with reference to Figure 1, a preferred embodiment of the drying device 100 according to the invention for a semiconductor wafer 200 to be dried with a drying hood unit 110 according to the invention with three transparent pane elements 111, 112, 113 for complete inspection of the surface of the semiconductor wafer 200 during the drying process during the method according to the invention by an operator is described.

[0062] The drying device 100 is designed to dry the wetted semiconductor wafer 200, temporarily arranged therein on a carrier unit 10, during a drying process by utilizing the known Marangoni effect after the semiconductor wafer 200 has undergone a cleaning step. The drying device 100 comprises the drying hood unit 110.

[0063] The drying hood unit 110 is thin-walled and shell-shaped and comprises a hood which, viewed in cross-section along its longitudinal axis, describes the geometric shape of an elliptical section, in particular essentially a quarter ellipse.

[0064] The hood comprises three transparent pane elements 111, 112, 113, which are arranged on differently geometrically aligned hood segments 121, 122, 123, wherein the hood comprises four hood segments 121, 122, 123, 124:

[0065] • a first hood segment 121, which essentially has the shape of an elliptical cylinder jacket section and is designed as a kind of cover surface of the hood,

[0066] • a second hood segment 122, which has substantially the shape of a rectangle and closes the hood on the side of the raised edge of the first hood segment 123, and a third 123 and a fourth 124 hood segment, each of which has the shape of an elliptical section.

[0067] The first hood segment 121 is frame-like, made of stainless steel, and the first transparent pane element 111 is arranged therein.

[0068] The second hood segment 122 is frame-like, made of stainless steel, and the second, transparent pane element 112 is arranged therein. The third hood segment 123 is frame-like, made of stainless steel, and the third, transparent pane element 113 is arranged therein. The fourth hood segment 124 is made entirely of stainless steel.

[0069] Three of the four hood segments are frame-like. This frame structure of the hood and the fourth, full-surface hood segment are made of electrically conductive material (stainless steel), and the three transparent pane elements are also made of electrically conductive material (in the form of ESD antistatic polycarbonate).

[0070] As can be seen in Figure 1, the geometry of the drying hood unit 110 is designed such that the clear distances between the semiconductor wafer 200 positioned on the carrier unit 10 within the drying device 100 and the three transparent wafer elements 111, 112, 113 are each kept small. The three transparent wafer elements 111, 112, 113 are arranged on differently geometrically aligned hood segments 121, 122, 123 such that, viewed over the entire drying process, all sections of the semiconductor wafer 200 that are essential for inspection, essentially the entire semiconductor wafer 200, which performs a guided movement over the carrier unit 10 within the drying device 100 during the drying process, are visually visible to the operator without restriction for inspecting the surface for undried areas.This allows the operator to visually monitor the drying progress and drying quality during the drying process.

[0071] A final inspection and final assessment of the drying progress and drying quality, in particular the assessment of whether at least one non-dried area remains on the surface of the semiconductor wafer 200 at the latest upon expiration of the specified drying time, can advantageously be carried out exclusively in a closed state of the drying hood unit 110 (or in a closed state of the drying device 100) with the semiconductor wafer 200 arranged therein in the carrier unit 10. The transparent pane elements 111, 112, 113 are tightly and detachably fixed to the drying hood unit 110, specifically within the associated, frame-like hood segment.

[0072] In the present embodiment, the operator did not observe any non-dried areas on the surface of the semiconductor wafer 200 during the inspection during the drying process. The drying time therefore essentially corresponds to the drying time of a comparative drying process during which a semiconductor wafer 200 is dried in a drying device with an opaque drying hood unit 110, but in the preferred embodiment, compared to known processes orComparison processes (POR) with the advantage described above that, due to the simultaneous assessment of the drying progress and the drying quality directly during the drying process, some drying-related inspection processes (as described at the beginning) after the removal of the semiconductor wafer 200 can be omitted (and thus, in absolute terms, the manufacturing time per semiconductor wafer 200 can be reduced for the entire manufacturing process of the semiconductor wafer 200).

[0073] In other words, in this specific case, the drying time already specified is sufficient for the final inspection by the operator to assess the drying quality.

[0074] It was also possible to determine that the process parameters for the specific drying process were set correctly.

[0075] After completion of the drying process, the semiconductor wafer 200 is arranged in a cassette unit temporarily docked to the drying device 100 (indicated purely schematically in Figure 1 ), and after filling the cassette unit with further semiconductor wafers that have undergone the drying process on the drying device 100, the cassette unit is manually transferred to the next process station (here a polishing station).

Claims

Claims 1 . A drying device which is designed to dry at least one wetted semiconductor wafer (200) temporarily arranged therein on a carrier unit (10) during at least one drying process, wherein the drying device (100) comprises a drying hood unit (110), characterized in that • the drying hood unit (110) comprises at least one transparent pane element (111, 112, 113) which is designed and arranged on the drying hood unit (110) in such a way that, in a closed state of the drying hood unit (110), it provides a substantially unrestricted optical view of substantially the entire surface of the arranged semiconductor wafer (200), in particular for at least one operator, when viewed from outside the drying device (100) via the at least one transparent pane element (111, 112, 113), over the entire at least one drying process.

2. Drying device according to claim 1, wherein the drying hood unit (110) is substantially thin-walled and / or shell-shaped and the at least one transparent pane element (111, 112, 113) is integrated into the shell, in particular is integrated into a shell part of a hood of the drying hood unit (110).

3. Drying device according to claim 1 or 2, wherein the drying hood unit (110) comprises a hood, in particular is designed as a hood (110), which, viewed in cross section along its longitudinal axis, essentially describes the geometric shape of an ellipse section, in particular a quarter ellipse, wherein the hood (110) comprises at least two transparent pane elements (111, 112, 113) which are arranged on differently geometrically aligned hood segments (121, 122, 123).

4. Drying device according to claim 3, wherein the hood has at least four Hood segments (121, 122, 123, 124), wherein a first hood segment (121), which essentially has the shape of an elliptical cylinder jacket section and is designed as a type of cover surface of the hood, and a second hood segment (122), which essentially has the shape of a rectangle and closes off the hood on the side of the raised edge of the first hood segment, and a third (123) and a fourth (124) hood segment each essentially have the shape of an elliptical section, in particular a quarter ellipse, wherein a transparent pane element is integrated into at least two of the at least four (121, 122, 123, 124) hood segments.

5. Drying device according to claim 4, wherein the first hood segment (121) is designed like a frame, in particular made of stainless steel or plastic, and a first, transparent pane element (111) is arranged therein, and the second hood segment (122) is designed like a frame, in particular made of stainless steel or plastic, and a second, transparent pane element (112) is arranged therein, and • the third hood segment (123) is frame-like, in particular made of stainless steel or plastic, and a third, transparent pane element (113) is arranged therein, and the fourth hood segment (124) is formed over the entire surface, in particular made of stainless steel or plastic, or • the fourth hood segment is designed like a frame, in particular from stainless steel or plastic, and a fourth, transparent pane element is arranged therein, and the third hood segment is designed over the entire surface, in particular from stainless steel or plastic.

6. Drying device according to one of the preceding claims, wherein • the geometry of the drying hood unit (110) is designed such that the clear distances between the semiconductor wafer (200) positioned on the carrier unit (10) within the drying device (100) and at least two transparent wafer elements (111, 112, 113) are kept small, and • the at least two transparent pane elements (111, 112, 113) are arranged on differently geometrically aligned hood segments (121, 122, 123) in such a way that, viewed over the entire drying process, all sections of the semiconductor wafer (200) that are essential for the inspection, in particular essentially the entire semiconductor wafer (200), which performs a guided movement over the carrier unit (10) within the drying device (100) during the at least one drying process, are optically visible.

7. Drying device according to one of the preceding claims, wherein the at least one transparent pane element (111, 112, 113) is made of electrically conductive material, in particular polycarbonate ESD antistatic, and / or wherein substantially the entire drying hood unit (110) is constructed from the at least one transparent pane element which is made of electrically conductive material, in particular polycarbonate ESD antistatic.

8. Drying device according to one of the preceding claims, wherein the at least one transparent pane element (111, 112, 113) is arranged in a tightly fixed manner on the drying hood unit (110), in particular on a frame-like hood segment of a hood of the drying hood unit (110), and / or the drying hood unit, in particular a hood of the drying hood unit, is at least partially constructed in a frame-like manner, said frame structure being made of an electrically conductive material.

9. A method for drying a semiconductor wafer (200) within a drying device (100) according to one of claims 1 to 8, after the at least one semiconductor wafer (200) has undergone at least one cleaning step, wherein • during at least one drying process, the surface of the at least one wetted semiconductor wafer (200), in particular substantially the entire surface, is dried, and • during the at least one drying process, the drying progress and the drying quality are visually inspected by at least one operator via an optical inspection of the drying device (100) from outside the drying device via the at least one transparent pane element (111, 112, 113).

10. The method according to claim 9, wherein the at least one drying process is assigned a predeterminable drying time, wherein the predeterminable drying time substantially corresponds to the predeterminable drying time of a comparison drying process during which at least one semiconductor wafer (200) is dried in a drying device (100) with an opaque drying hood unit (110).

11. Method according to claim 9 or 10, wherein a final inspection and final assessment of the drying progress and the drying quality, in particular of the assessment of whether at least one non-dried area has remained on the surface of the semiconductor wafer (200) at the latest upon expiry of the predetermined drying time, takes place exclusively in a closed state of the drying hood unit (110) with the at least one semiconductor wafer (200) arranged therein in the carrier unit (10) via the optical inspection by the at least one operator from the outside via the at least one transparent pane element (111, 112, 113).

12. Method according to one of claims 9 to 11, wherein the at least one operator is able to inspect the substantially complete surface the at least one semiconductor wafer (200) changes locally between at least two positions during the drying process in order to carry out an inspection via at least two different, in particular three, transparent wafer elements (111, 112, 113).

13. The method according to any one of claims 9 to 12, wherein • during the at least one drying process, if at least one non-dried area is detected by the at least one operator on the at least one semiconductor wafer (200), the operator intervenes essentially directly by adjusting at least one process parameter on the drying device (100) in order to provide stable process conditions leading to completely dried semiconductor wafers for the subsequent drying processes for the semiconductor wafers (200) introduced subsequently, wherein at least one of the following process parameters is adjusted: printing parameters, printing cascade, concentration gradient, speed of the semiconductor wafer during the drying process, acceleration of the semiconductor wafer during the drying process, • after completion of the at least one drying process, the at least one semiconductor wafer (200) is arranged in a cassette unit temporarily docked to the drying device (100), and • after at least partially filling the cassette unit with at least one semiconductor wafer (200), the cassette unit is transferred to the next process station, manually or mechanically.

14. The method according to claim 13, wherein during the at least one Drying process: • the adjustment of at least one process parameter comprises the step of the operator extending the predetermined drying time of the current drying process by an extension period via a setting on the drying device (100) sets or starts a further drying process for the currently at least one semiconductor wafer (200) if the assessment of the optical shape of the at least one non-dried region on the at least one semiconductor wafer (200) during the drying process by the operator via the optical inspection via the at least one transparent wafer element (111, 112, 113) is such that by directly intervening for a temporal extension of the current drying process, in particular by a value in a range of 1 s to 60 s, it can be expected that the at least one non-dried region on the at least one semiconductor wafer (200) will be substantially completely removed by the drying process at the latest upon expiration of the extension period.

15. The method according to claim 13 or 14, wherein the at least one semiconductor wafer (200) within the cassette unit is fed as the next process station to a renewed cleaning step on the cleaning line upstream of the drying device (100) in the form of the next process station if the prior assessment by the operator at the drying device (100) for this at least one semiconductor wafer (200) via the optical inspection via the at least one transparent pane element (111, 112, 113) showed that the optical shape of the at least one non-dried region on the at least one semiconductor wafer (200) during the drying process or during the drying process extended by an extension period is so pronounced that a renewed cleaning step with a subsequent renewed drying process within the drying device (100) is necessary.

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