Multi-row carrier cassette for semiconductor wafers, method for using a carrier cassette and method for treating wafers with a treatment fluid using a carrier cassette

Abstract

A wafer holder cassette has two side plates opposite each other in a first direction, each with a locking groove on its upper side, at least one lower retaining bar mounted between the two opposing side plates, and at least two lateral retaining bars opposite each other in a second direction, also mounted between the two opposing side plates, and an upper locking bar that can be locked in the locking grooves of the opposing side plates to hold wafers in the holder cassette. The side plates, the lower retaining bar, the at least two lateral retaining bars, and the upper locking bar define two receiving areas for two rows of wafers extending in the first direction, the two receiving areas being arranged side by side in the second direction.The upper locking bar is designed to hold down the two rows of wafers and has projections designed to separate adjacent wafers of both rows in the first direction when the upper locking bar is locked in the locking grooves.

Description

[0001] The present invention relates to carrier cassettes for semiconductor wafers, and in particular to carrier cassettes for semiconductor wafers that enable the treatment of semiconductor wafers in batch mode. Such wafer carriers, typically also referred to as baskets or carriers, are used to place multiple wafers in a tank in batch mode and treat them there with a treatment liquid.

[0002] Various carrier cassettes are known from the state of the art.

[0003] For example, DE 20 2015 104 876 U1 discloses a substrate carrier for solar cells, which has two opposing side plates, between which side rods and base rods are arranged. Notches are provided on the upper side of the side plates, into which a pressure rod can be inserted and locked by rotating the pressure rod. The side rods and base rods each have teeth by which adjacent wafers arranged between the side plates can be separated from each other. The substrate carrier is designed to accommodate a row of wafers between the two side plates and to hold them in place by locking the pressure rod in the notches.

[0004] From DE 10 2015 224 980 B4 a cassette for holding the plate-shaped elements is known, which is also designed to hold a row of wafers between two side plates, and which in Fig. 12a of the present application. The cassette has two side plates 2, 4, between which six receiving rods or toothed racks 6 are arranged. The toothed racks 6 are firmly connected to the side plates 2 and 4. A locking bar is also designed as a toothed rack. The locking bar 8 can be locked in engagement sections 10 formed in the upper sides of the side plates 2, 4. Each engagement section 10 has two grooves into which pins of the locking bar fit, so that the locking bar can be locked in the engagement sections. The side plates 2 and 4 also have hooks / receiving means 12 in their upper sides, which enable the cassette to be inserted or removed, for example from a basin.

[0005] EP 4 113 586 A1 discloses a wafer carrier that also has two opposing side plates and support rods mounted between the opposing side plates. The side walls each have at least one groove for receiving at least one movable support rod. Thus, two wafers can be arranged one above the other in the wafer carrier, with the at least one movable support rod arranged between the two wafers.

[0006] A simplified schematic cross-sectional view of a carrier cassette similar to that shown in Fig. 12a is shown in Fig. 12b. As shown in Fig. 12b, the bars 6 and 8 of the basket have elements in the form of projections 16 which prevent mutual contact of adjacent wafers, such a wafer 20 in Fig. 12b. The locking bar 8 serves to prevent the wafer 20 from escaping upwards from the carrier cassette. The locking bar 8, which can also be referred to as a hold-down device or pressure bar, is not permanently mechanically bound to the basket, but can be locked in the mechanism 10. A carrier cassette, as shown in the Fig. 12a and Fig. 12b, has only one receiving area for wafers arranged one behind the other, which is closed by the locking bar 8. The carrier cassette is designed in particular for the treatment of square wafers.

[0007] The production of solar cells requires various treatments of wafers, especially silicon wafers, including etching, cleaning, and drying. Carrier cassettes must be designed in such a way that the wafers do not touch each other during the treatment steps, as this could lead to surface inhomogeneities. Furthermore, buoyancy of the wafers due to reactions and reaction products occurring during etching processes must be prevented, as this could lead to a loss of wafers from the carrier cassette and / or undesirable mutual contact between the wafers.

[0008] Cost pressure is a significant issue in the solar industry. Reducing wafer thickness is a key factor in lowering the cost of solar modules, particularly the cost per watt. The thinner the wafers, the cheaper they become due to a corresponding reduction in the silicon material. The trend is towards using material with a thickness of less than 100 µm, although the current standard thickness of M12 / G12 wafers is between 170 and 150 µm. One limitation arises during the wet-chemical treatment. The thinner the wafers, the more they tend to stick together during the process, meaning the greater the distance between wafers (pitch distance) in the carrier cassette must be selected to prevent sticking.The larger the pitch distance, the fewer wafers fit in a carrier cassette and the smaller the throughput of a treatment machine, which ultimately leads to higher costs.

[0009] During wet-chemical processing, the wafer support on the rods or the spacers in the form of the rod protrusions can cause shadows on the wafers, also known as carrier marks, which are caused by flow during the etching process. These shadows are visible after the wet-chemical treatment and are often considered a cosmetic defect, which can lead to problems with satisfaction and machine acceptance.

[0010] The object of the present invention is to provide alternative carrier cassettes for wafers that enable increased throughput at reduced wafer costs, as well as to provide methods for using carrier cassettes and methods for processing wafers.

[0011] This object is achieved by a carrier cassette according to claim 1 and methods according to claims 17 and 18. Further developments of the invention are set out in the dependent claims.

[0012] According to embodiments, a wafer carrier cassette comprises two side plates facing each other in a first direction, each of which has a locking groove on an upper side thereof, at least one lower retaining bar mounted between the two facing side plates, at least two lateral retaining bars mounted between the two facing side plates in a second direction, and an upper locking bar lockable in the locking grooves of the opposing side plates to hold down wafers in the carrier cassette. The side plates, the lower retaining bar, the at least two lateral retaining bars, and the upper locking bar define two receiving areas for two rows of wafers extending in the first direction, wherein the two receiving areas are arranged side by side in the second direction.The upper locking bar is configured to hold down the two rows of wafers and has projections configured to separate adjacent wafers of both rows from each other in the first direction when the upper locking bar is locked in the locking grooves.

[0013] According to the invention, two receiving areas for two rows of wafers are provided horizontally next to each other in the carrier cassette, which makes it possible to provide a common upper locking bar for both receiving areas. This enables a simple construction of a carrier cassette in which two adjacent rows of wafers can be held in the carrier cassette by a common locking bar during treatments such as those required in the manufacture of solar cells, such as etching, cleaning, or drying. The projections in the locking bar prevent the wafers from touching each other during the treatment steps, thus preventing inhomogeneities on the surface.

[0014] In embodiments, the projections of the locking bar can have a first row of projections configured to separate adjacent wafers of one of the two rows from one another in the first direction, and a second row of projections configured to separate adjacent wafers of the other of the two rows from one another in the first direction. The projections of the first row of projections can extend at a first angle from the upper locking bar, and the projections of the second row of projections can extend at a second angle from the upper locking bar. Providing separate rows of projections for the individual rows of wafers makes it possible to reduce the material required for the projections and prevent mutual contact between adjacent wafers of both rows.

[0015] In embodiments, the projections may comprise a series of projections, each of which is configured to separate adjacent wafers of both rows from each other in the first direction. In such embodiments, the locking bar may have a simple structure while simultaneously preventing mutual contact between adjacent wafers in the two horizontally adjacent rows.

[0016] In embodiments, the carrier cassette further comprises means for separating the two receiving areas from one another in the second direction. Such means can be provided in addition to the support rod. The separating means can delimit the first receiving area and the second receiving area on the mutually facing sides.

[0017] In embodiments, the means for separating the two receiving areas comprise a central support rod mounted between the side plates and separating the two receiving areas from each other in the second direction. In such examples, the central support rod may have projections for separating adjacent wafers of the two rows of wafers from each other in the first direction. Such embodiments make it possible to hold the wafers stably within the two receiving areas, since rods can be provided that delimit the respective receiving area on all four sides.

[0018] In embodiments, the lower support rod can have a continuous or discontinuous web designed to separate adjacent wafers from one another in the second direction. The web represents the means for separating the two receiving areas in the second direction. In other words, the lower support rod can have the means for separating the wafers of the two horizontally adjacent wafer rows from one another. This reliably prevents contact between wafers in the first row and wafers in the second row.

[0019] In some embodiments, the lower support rod is configured to delimit both receiving areas at the bottom. Such examples enable a carrier cassette with a simple structure, since only one lower support rod is required.

[0020] In embodiments, the carrier cassette may have two lower support rods mounted between the two opposite side plates, each of which defines one of the two receiving areas at the bottom. In such examples, the stability of the wafers held in the receiving areas may be increased.

[0021] In embodiments, the at least two lateral holding rods and / or the at least one lower holding rod can have projections that are designed to separate adjacent wafers from one another in the first direction. In embodiments in which a lower holding rod is provided for both rows of wafers, this holding rod can have projections that are designed to separate adjacent wafers of both rows from one another in the first direction, for example by means of projections extending in different directions or by means of projections that are designed to separate adjacent wafers of both rows from one another in the first direction. Embodiments thus make it possible to increase the reliability with which adjacent wafers are prevented from touching one another.

[0022] Embodiments enable the processing of cut wafers by closing two receiving areas for the wafers in the carrier cassette by the locking bar. In embodiments, a dimension of the two receiving areas in one direction between the at least one lower support bar and the locking bar is twice as large as a dimension of the two receiving areas in the second direction. Embodiments thus enable the processing of halved wafers side by side in a carrier cassette.

[0023] Embodiments enable the processing of wafers with a smaller surface area, allowing wafer thickness to be reduced, for example, to a thickness of less than 100 µm with a small pitch of less than 5 µm, without the risk of adjacent wafers touching or sticking together. This can enable a throughput of up to 18,400 wafers per hour (wph) in embodiments.

[0024] Furthermore, embodiments allow for a reduction in the wafer support positions in the carrier cassette. Typical standard M12 / G12 carrier cassettes have nine rods, resulting in nine support points and correspondingly nine carrier marks. Embodiments allow for a reduction to four to eight rods, which reduces the support points and carrier marks accordingly.

[0025] By enabling the processing of thinner wafers and also adjacent rows of wafers, embodiments of the invention enable an increase in throughput when processing sliced ​​wafers using a carrier cassette. Only one locking bar is required to vertically delimit two receiving sections, or treatment chambers, in a carrier cassette. This simplifies automation and material usage.

[0026] In embodiments, the carrier cassette can have more than two receiving areas arranged next to one another in the horizontal direction.In embodiments, the carrier cassette has a plurality of upper locking bars and the side plates each have a plurality of locking grooves, wherein the side plates, the lower holding bar, the at least two lateral holding bars and the plurality of upper locking bars delimit more than two receiving areas for more than two rows of wafers extending in the first direction, wherein the more than two receiving areas are arranged next to one another in the second direction and wherein each of the upper locking bars is designed to hold down two rows of wafers that are adjacent in the second direction, and wherein each of the upper locking bars has projections that are designed to separate wafers of the two rows that are adjacent in the first direction from one another when the upper locking bar is locked in two respective ones of the locking grooves.Embodiments thus enable a further increase in throughput by designing the carrier cassette to accommodate more than two rows of wafers arranged side by side in the horizontal direction.

[0027] In embodiments, the respective projections of the locking bar and / or the support rods are configured to position rows of wafers with a thickness of ≤ 160 µm, preferably ≤ 100 µm, with a distance of ≤ 7 mm, preferably ≤ 5 mm, between wafers in the first direction in the receiving areas. Embodiments thus enable increased throughput due to the ability to process thin wafers with a small distance between them.

[0028] In some embodiments, the side plates have receiving means on the upper side for mechanical handling of the carrier cassettes. Some embodiments thus enable automated production of wafers for solar cells by means of a wet-chemical treatment of halved or multiply cut semiconductor wafers, such as silicon wafers.

[0029] In embodiments, the carrier cassettes are designed to process wafers in batch mode. The wafers can be semiconductor wafers, for example, silicon wafers. The wafers can be halved or multiply cut wafers. In embodiments, the wafers can be rectangular wafers obtained by halving square wafers, with one side being twice as long as the other side. In embodiments, the carrier cassettes or receiving areas thereof are designed to receive two rows of such wafers edgewise next to one another.

[0030] Embodiments relate to a use of such carrier cassettes, in particular for treating wafers with a treatment liquid in batch operation, wherein two rows of wafers are placed next to each other in the carrier cassette.

[0031] Embodiments provide methods for treating wafers with a treatment liquid using a carrier cassette as described herein, comprising the following steps: placing two rows of wafers next to each other in the carrier cassette; locking the upper locking bar in the locking grooves to hold down the two rows of wafers with the locking bar; and placing the carrier cassette with the wafers into a bath containing the treatment liquid to subject the wafers to treatment with the treatment liquid. Short description of the drawings

[0032] Examples of the invention are explained in more detail below with reference to the accompanying drawings. They show: Fig. 1 a schematic representation of an embodiment of a carrier cassette according to the invention; Fig. 2 to 5 show schematic cross-sectional views of embodiments of carrier cassettes according to the invention; Fig. 6a to 6c are schematic representations of embodiments of upper locking bars; Fig. 7a to 7c are schematic representations for explaining an embodiment of a carrier cassette according to the invention; Fig. 8a and Fig. 8b schematic representations to explain a configuration of an embodiment of a lower support rod; Fig. 9 is a schematic diagram illustrating an embodiment with more than two rows of wafers arranged side by side; Fig. 10a to 10c are schematic representations for explaining embodiments of middle support rods; Fig. 11 is a schematic diagram illustrating an embodiment with more than two horizontal rows of wafers arranged side by side; and Fig. 12a and Fig. 12b an isometric view and a schematic cross-sectional view of a known carrier cassette.

[0033] Examples of the present invention are described in detail below with the use of the accompanying drawings. It should be noted that like elements or elements having the same functionality are provided with the same or similar reference numerals, and repeated description of elements provided with the same or similar reference numerals is typically omitted. Descriptions of elements having the same or similar reference numerals may be interchangeable. In the following description, many details are described in order to provide a more thorough explanation of examples of the invention. However, it will be apparent to those skilled in the art that other examples may be implemented without these specific details.Features of the different examples described may be combined with each other unless features of a corresponding combination are mutually exclusive or such a combination is expressly excluded.

[0034] Fig. 1 shows an embodiment of a carrier cassette having a first side plate 52 and a second side plate 54 that oppose each other in a first direction. The first side plate 52 has a locking groove 56 on an upper side thereof, and the side plate 54 has a locking groove 58 on an upper side thereof. Between the side plates 52 and 54, a lower support rod 60 is provided that extends in the first direction. The lower support rod 60 is fixedly attached to the first side plate 52 and the second side plate 54. Furthermore, two lateral support rods 62 and 64 are provided between the first side plate 52 and the second side plate 54. The two lateral support rods 62 and 64 can oppose each other in a second direction that is perpendicular to the first direction.The side support rods 62 and 64 are fixedly attached to the first side plate 52 and the second side plate 54 and thus define, together with the side plates 52 and 54 and the lower support rod 60, a rigid carrier cassette.

[0035] The carrier cassette further comprises an upper locking bar 70 which can be locked in the locking grooves 56 and 58 of the opposing side plates 52 and 54 to hold down wafers W1, W2 in the carrier cassette. Although only two wafers in Fig. 1, it requires no further explanation that a plurality of wafers, for example more than 50 or more than 100 wafers, can be arranged next to one another in the first direction, or the carrier cassette is designed to accommodate such a plurality of wafers.

[0036] The side plates 52, 54, the lower support rod 60, the lateral support rods 62, 64 and the upper locking rod 70 define two receiving areas for two rows of wafers extending in the first direction, wherein the two receiving areas are arranged side by side in the second direction, which is perpendicular to the first direction. Of the two rows of wafers, Fig. 1, for the sake of clarity, only one wafer is shown at a time: wafer W1 of the first row of wafers and wafer W2 of the second row of wafers. The upper locking bar 70 is designed to hold down the two rows of wafers. For this purpose, the locking bar 70 can be arranged centrally in the second direction. The locking bar has dimensions in the second direction such that it comes into contact with both rows of wafers simultaneously when it is locked in the locking grooves 56, 58. The locking bar 70 has projections 72 which are designed to separate adjacent wafers of both rows from one another in the first direction when the upper locking bar 70 is locked in the locking grooves 56 and 58.

[0037] Since the extension of the carrier cassette in the direction between the two side plates 52 and 54 is generally greater than in the second direction perpendicular thereto, the first direction will be referred to below as the longitudinal direction for the sake of simplicity, while the second direction will be referred to below as the transverse direction for the sake of simplicity. The direction perpendicular to the longitudinal direction and the transverse direction between the lower holding rod 60 and the locking rod 70 will be referred to below as the vertical direction for the sake of simplicity. The vertical direction can correspond to the direction in which the carrier cassette is immersed in a wafer bath and removed from the wafer bath.

[0038] The first receiving area is delimited in the transverse direction on the outer side by the lateral holding rod 62, on the upper side by the locking rod 70, and on the lower side by the lower holding rod 60. The second receiving area is delimited on the outer side by the lateral holding rod 64, on the upper side by the locking rod 70, and on the lower side by the lower holding rod 60. In the longitudinal direction, the two receiving areas are delimited by the respective side plates 52 and 54, respectively. The holding rod 70 can be designed to delimit the receiving areas on the side facing each other, for example, by parts of the holding rod 70 protruding between wafers spaced apart in the transverse direction. As explained below, additional means can be provided to delimit the receiving areas on the inner side, i.e., to separate wafers adjacent in the transverse direction from one another.Such limiting means may, in examples, be formed by a continuous or interrupted web on the lower support rod, or by one or more central support rods provided between the receiving areas and firmly connected to the side plates.

[0039] The projections 72 are provided to protrude into the receiving areas in order to separate longitudinally adjacent wafers in both rows from one another. The locking bar 70 can be configured to be locked by rotation in the locking grooves 60 and 58, wherein in the locked state the projections 72 protrude into the receiving areas for the above-mentioned purpose. For this purpose, the locking bar and the locking grooves can be designed as described, for example, in the above-mentioned documents DE 20 2015 104 876 U1 or DE 10 2015 224 980 B4. However, it does not require a separate explanation that the locking bars and the locking grooves can be designed in any suitable manner to enable locking of the locking bar in the locking grooves. For example, the locking bar can have an oval or eccentric shape in cross-section in order to be locked by rotation in a locking groove.

[0040] To hold down both rows of wafers, the locking bar 70 is positioned centrally in the transverse direction above the two receiving areas and thus above the two wafers received in the receiving areas. In the locked state, the dimension of the locking bar in the transverse direction is larger than the distance between the wafers W1, W2, at least in the areas where the wafers are to be held down, so that both wafers can be held down.

[0041] Although in Fig. 1 only one lower support rod 60 is shown, in other embodiments two or more lower support rods may be provided. Although in Fig. 1 only one holding rod 62 or 64 is provided on each side in the transverse direction, in embodiments more than one side rod, for example two side rods, can be provided.

[0042] Although it is in Fig. 1, the holding rods 60, 62, 64 can also have respective projections to separate longitudinally adjacent wafers in the two rows from one another. The projections can be designed as disclosed in the above-mentioned documents DE 20 2015 104 876 U1 and DE 10 2015 224 980 B4. For example, the holding rods can be formed by toothed racks with teeth and intermediate spaces, so that a tooth is arranged between wafers adjacent in the longitudinal direction. The projections in the hold-down rod can also be formed by corresponding teeth to achieve the described functionality.

[0043] Examples of different arrangements of lateral and lower support rods are described below with reference to the Fig. 2 to 5 are explained in more detail. Fig. 2 to 5 represent schematic cross-sectional views (section in the transverse and vertical directions). In the examples shown, the upper locking bar 70 has a first row of projections 72a and a second row of projections 72b. The first row of projections 72a protrudes into the first receiving area, in which the row of wafers, to which the wafer W1 belongs, is arranged, and the second row of projections 72b protrudes into the second receiving area, in which the second row of wafers, to which the wafer W2 belongs, is arranged. Receiving means 12 for mechanical handling of the carrier cassette are provided on the upper side of the side plates, for example in the form of hooks, as shown schematically.

[0044] In the Fig. In the embodiments shown in Figure 2, two lateral support rods 62a, 62b and 64a, 64b are provided on each side in the transverse direction, which are arranged one above the other. Furthermore, in the embodiment shown, two lower support rods 60a and 60b are provided. The lower support rod 60a defines the first receiving area at the bottom, and the lower support rod 60b defines the second receiving area at the bottom. As further shown in Fig. 2, the respective support rods are provided with projections 80 to separate adjacent wafers from each other in the longitudinal direction.

[0045] The Fig. The embodiment shown in Figure 3 differs from the one shown in Fig. 2 in that only one lower holding rod 60 is provided. The lower holding rod 60 is provided centrally below the two receiving areas in the transverse direction, wherein the dimensions of the holding rod 60 in the transverse direction are larger, at least in the sections in which the wafers are to be held, than a distance between the wafers adjacent in the transverse direction, so that both transversely adjacent rows can be held jointly by the lower holding rod 60. In the example shown, the lower holding rod 60 has projections 80a and 80b, wherein the projections 80a extend into the first receiving area and the projections 80b into the second receiving area. Like the projections 72a and 72b, the projections 80a and 80b thus extend at different angles from the lower holding rod 60 and the upper locking rod 70, respectively.Thus, longitudinally adjacent wafers in both rows can be separated from each other by the projections 80a, 80b.

[0046] Fig. 4 shows an embodiment that differs from that shown in Fig. 3 in that only one lateral holding rod 62 or 64 is provided, and that a central holding rod 90 is provided in the transverse direction between the two receiving areas. The central holding rod 90 is provided with projections 92a and 92b. The projections 92a protrude into the first receiving area and the projections 92b protrude into the second receiving area. The projections 92a and 92b are thus designed to separate wafers in both rows that are adjacent in the longitudinal direction from one another. The projections 92a and 92b are optional. The central holding rod 90 represents a means for delimiting the two receiving areas in the transverse direction on the side on which they face each other. This makes it more reliable to ensure that wafers that are adjacent in the transverse direction do not come into contact with one another.

[0047] The Fig. The embodiment shown in Figure 5 differs from the one shown in Fig. 4 in the design of the lower support rod 60 and in particular in the configuration of the projections 80a and 80b. In the example shown, the projections have a section extending in the transverse direction and a section extending in the vertical direction, with at least the section extending in the vertical direction projecting into the first and second receiving areas. In such embodiments, the section of the projections extending in the transverse direction could also be continuous in order to provide a support for the wafers and thereby hold them from below.

[0048] As in the Fig. 2 to 5, in the embodiments in which a central support rod is provided, the diameter of the lateral and central support rods can be smaller than in the embodiments in which no central support rod is provided, so that the external dimensions of the carrier cassettes are the same.

[0049] Referring to the Fig. 6a to 6c describe embodiments of how the upper locking bar can be implemented.

[0050] In the Fig. In the example shown in Figure 6a, the upper locking bar has two rows of protrusions 72a and 72b, as described above. The protrusions 72a and 72b extend in different directions from the locking bar 70 and each protrude into the space between two longitudinally adjacent wafers to separate them. The protrusions 72a and 72b can be formed by respective teeth. For example, an angle of 90° can be formed between the protrusions 72a and 72b, with one protrusion extending at an angle of 45° with respect to the height direction and one protrusion extending at an angle of -45° with respect to the height direction.

[0051] According to Fig. 6b, the locking bar 70 has a series of projections 72c, each of which is configured to separate adjacent wafers of both rows from each other in the first direction. For this purpose, each of the individual projections 72c is configured to protrude into the space between longitudinally adjacent wafers of both rows, so that the wafers of both rows can be separated from each other. In other words, each projection has a dimension in the transverse direction that is greater than the distance between transversely adjacent wafers.

[0052] According to Fig. 6c, the locking bar 70 has four rows of projections 72d, each extending in directions 90° apart from the locking bar 70. This embodiment allows for increased flexibility with regard to the orientation of the locking bar 70 relative to the receiving areas and thus the wafers. If the respective projections are sufficiently wide, it can be ensured that the longitudinally adjacent wafers are separated from one another, regardless of the orientation of the locking bar 70 relative to the receiving areas.

[0053] To illustrate this, the Fig. 7a to 7c a schematic perspective view of the Fig. 3, but the side support rods are omitted for clarity. As in Fig. As can be seen in Figure 7a, the projections 72a and 72b are designed as teeth that extend in different directions from the locking bar 70. Fig. Figure 7b shows a schematic top view, wherein, for simplicity, only two wafers W1 of the first row of wafers and two wafers W2 of the second row of wafers are shown. A respective tooth 72a is arranged between two wafers W1 of the first row, and a respective tooth 72b is arranged between two wafers W2 of the second row. Fig. Figure 7c shows a perspective view of a support rod or locking bar, which may be the support rod 60 or the locking bar 70, or at least a portion of the locking bar 70. As shown, the respective projections extend in two different directions from the rod, so that they protrude into the respective receiving areas and thus between the longitudinally adjacent wafers. It should be noted that in embodiments, the locking bar and the lower support rod 60 may have a substantially identical structure with regard to the projections.

[0054] In some embodiments, the protrusions of the support rods may have a shark-tooth design, while the protrusions of the locking rod may have a fishbone design. If the lower support rod also serves to hold more than one row of wafers, it may also have a fishbone design.

[0055] A further embodiment is described with reference to the Fig. 8a and Fig. 8b. The Fig. 8a and Fig. The example shown in Figure 8b differs from the one referring to the Fig. 7a to 7c by the design of the lower support rod 60. In the example shown in the Fig. 8a and Fig. In the example shown in Figure 8b, the lower support rod 60 has a continuous web 94 designed to separate the transversely adjacent wafers W1 and W2 from one another. For this purpose, the web 94 protrudes into a gap between the transversely adjacent wafers W1 and W2. In other words, the web protrudes from the lower support rod 60 in the direction of the locking rod 70. As a result, the web 94 delimits the two receiving areas to the inside, i.e., between the two rows of wafers. In embodiments, the web can also have interruptions, as long as it is provided in the areas where wafers are opposite one another in the transverse direction. The web 94 thus represents a means for separating transversely adjacent wafers.

[0056] Fig. 9 shows a schematic perspective view of an embodiment which differs from the Fig. 7a in that the carrier cassette is designed to accommodate three horizontally adjacent rows of wafers. As shown in Fig. As shown in Figure 9, the first side plate 52 has a further locking groove 56a on its upper side, and the second side plate 54 has a further locking groove 58a on its upper side. Furthermore, a further upper locking bar 70a is provided, which can be locked in the locking grooves 56a and 58a. The further locking bar 70a is designed to hold down the row of wafers W2 and a further row of wafers W3. Furthermore, the further locking bar 70a in turn has projections that are designed to separate wafers of the two rows of wafers W2 and W3 that are adjacent in the longitudinal direction from one another when the upper locking bar 70a is locked in the locking grooves 56a and 58a. Furthermore, a further lower holding bar 60a is provided, which is firmly attached between the first side plate 52 and the second side plate 54.The structure of the second retaining rod 60a can correspond to the structure of the first retaining rod 60, with corresponding projections 80a and 80b. Similarly, the structure of the further locking rod 70a can correspond to the structure of the first locking rod 70, with corresponding projections 72a and 72b. In the embodiment shown in FIG. Fig. In the example shown in Figure 9, in which the lateral support rods are again omitted for clarity, the carrier cassette thus has three receiving areas defined by the two upper locking bars 70, the lower support rods 60 and 60a, the side plates, and the lateral support rods. It goes without saying that more than three corresponding receiving areas may be provided in exemplary embodiments.

[0057] Examples of central support bars for separating transversely adjacent wafers will now be described with reference to the Fig. 10a to 10c.

[0058] According to Fig. 10a, a central support rod 90 is provided between the two receiving areas and thus between the two rows of wafers W1 and W2. The central support rod 90 extends from the first side plate 52 to the second side plate 54 and is attached to the same. The central support rod thus represents a means for separating the two rows of wafers from each other. In the example shown, the support rod 90 has no projections. In alternative embodiments, the support rod can have corresponding projections 92a and 92b, as described above with reference to the Fig. 4 and Fig. 5 described.

[0059] The Fig. The example shown in Figure 10b differs from the one in Fig. 10a in that two central support rods 90a and 90b are provided one above the other in the vertical direction. Such an arrangement can be advantageous for more reliably preventing transversely spaced wafers from coming into contact with each other.

[0060] The Fig. The example shown in 10c differs from the one in Fig. 10b in that the two superimposed middle support rods 90a and 90b have respective projections 92a and 92b, as described above with reference to the Fig. 4 and Fig. 5. This makes it possible to more reliably ensure in embodiments that wafers adjacent in the longitudinal direction do not come into contact with each other.

[0061] In embodiments, separating means are thus provided in order to separate wafers adjacent to one another in the transverse direction, wherein such separating means can be provided, for example, in the form of a web of the lower holding rod or in the form of one or more central holding rods.

[0062] Fig. Figure 11 shows a schematic cross-sectional view to explain how a carrier cassette could be expanded. A solid line 100 schematically shows a side wall for a carrier cassette for two rows of wafers W1 and W2, a dashed line 102 schematically shows a side wall for a carrier cassette for four rows of wafers W1 to W4, and a dash-dotted line 104 schematically shows a side wall for a carrier cassette for six rows of wafers W1 to W6. Carrier cassettes can generally be expanded as desired. Although in Fig. 11 different designs of the middle support rods are shown, it is needless to say that this does not represent any limitation, whereby the same or no middle support rods could be used, whereby middle support rods could also be provided between the wafers W2 and W3 and / or W4 and W5.

[0063] Although specific embodiments have been described above, it is not necessary to explain separately that the features of the embodiments can be combined with each other, unless explicitly stated otherwise. Fig. 1 shown carrier cassette with all features as they refer to the Fig. 2 to 10c. For example, the lower support rod 60, as shown in Fig. 5, the support rod as shown in Fig. 3 shown.

[0064] The present invention thus provides a carrier cassette, which can also be referred to as a substrate carrier, which with its components delimits at least two receiving areas arranged next to one another, wherein the locking bar is designed such that it delimits two receiving areas in the carrier cassette at the top, i.e., that it can hold down two rows of wafers. To this end, embodiments of the invention provide an apparatus for processing semiconductor wafers, comprising two side plates, on each side at least one bar for laterally holding the substrates, on the upper side a removable bar, and optionally further bars that segment the carrier cassette so that at least two areas for receiving substrates are created, wherein the pressure bar is designed such that it delimits at least two receiving areas.Limitation can also be achieved by a central bar firmly connected to the side plates. A corresponding device can also be designed for transporting and storing semiconductor wafers. Examples include reducing sticking effects, reducing carrier marks, increasing throughput, increasing customer satisfaction, and increasing competitiveness.

[0065] Embodiments of the invention are particularly suitable for handling halved or multiply cut silicon wafers, as they allow two cut halves to be processed side by side in a carrier cassette in a batch process. Treating cut wafers can be advantageous because it can reduce the occurrence of bending, allowing the use of thinner wafers and thus increasing throughput.

[0066] Examples of the invention also relate to a method for using a corresponding carrier cassette, in which two rows of wafers are placed side by side in the carrier cassette, whereupon the cassette with the wafers is immersed in a bath containing a treatment liquid to subject the wafers to a treatment, for example, etching or cleaning. Examples of the present invention thus also relate to a method for processing wafers in a batch operation, in which several rows of wafers are placed side by side in a corresponding carrier cassette, and the carrier cassette is then immersed in a liquid bath for the corresponding treatment.

[0067] Although features of the invention have been described in each case with reference to device features or method features, it will be apparent to those skilled in the art that corresponding features can also be part of a method or device. Thus, the device can be configured to perform corresponding method steps, and the respective functionality of the device can represent corresponding method steps.

Claims

[1] Carrier cassette for wafers (W1 - W5) with the following features: two side plates (52, 54) opposite each other in a first direction, each of which has a locking groove (56, 56a, 58, 58a) on an upper side thereof; at least one lower support rod (60, 60a, 60b) mounted between the two opposite side plates (52, 54), and at least two lateral support rods (62, 64) mounted between the two opposite side plates (52, 54), an upper locking bar (70, 70a) which can be locked in the locking grooves (56, 56a, 58, 58a) of the opposite side plates (52, 54) in order to hold down wafers (W1 - W5) in the carrier cassette, where the side plates (52, 54), the at least one lower support rod (60, 60a, 60b), the at least two lateral support rods (62, 64) and the upper locking rod (70, 70a) define two receiving areas for two rows of wafers (W1 - W5) extending in the first direction, wherein the two receiving areas are arranged next to one another in a second direction which is perpendicular to the first direction, and the upper locking bar (70, 70a) is designed to hold down the two rows of wafers (W1 - W5) and has projections (72, 72a - 72d) which are designed to separate adjacent wafers (W1 - W5) of both rows from one another in the first direction when the upper locking bar (70, 70a) is locked in the locking grooves (56, 56a, 58, 58a). [2] Carrier cassette according to claim 1, wherein the projections (72, 72a - 72d) comprise a first row of projections (72a, 72d) which are designed to separate, in the first direction, adjacent wafers (W1 - W5) of one of the two rows from one another, and a second row of projections (72b, 72d) which are designed to separate, in the first direction, adjacent wafers (W1 - W5) of the other of the two rows from one another. [3] A carrier cassette according to claim 2, wherein the projections (72a, 72d) of the first row of projections (72a, 72d) extend at a first angle from the upper locking bar (70, 70a), and the projections (72b, 72d) of the second row of projections (72b, 72d) extend at a second angle from the upper locking bar (70, 70a). [4] Carrier cassette according to claim 1, wherein the projections (72, 72a - 72d) comprise a series of projections (72c), each of which is designed to separate adjacent wafers (W1 - W5) of both rows from each other in the first direction. [5] A carrier cassette according to any one of claims 1 to 4, further comprising means for separating the two receiving areas from each other in the second direction. [6] A carrier cassette according to claim 5, wherein the means for separating comprises a central support rod (90, 90a, 90b) mounted between the side plates (52, 54) and separating the two receiving areas from each other in the second direction. [7] Carrier cassette according to claim 6, wherein the central support rod (90, 90a, 90b) has projections (92a, 92b) for separating adjacent wafers (W1 - W5) of the two rows from each other in the first direction. [8] Carrier cassette according to claim 6 or 7, wherein the means for separating comprise a continuous or interrupted web (94) of the at least one lower support rod (60, 60a, 60b) which is designed to separate adjacent wafers (W1 - W5) from one another in the second direction. [9] Carrier cassette according to one of claims 1 to 8, wherein the at least one lower holding rod (60) is designed to delimit both receiving areas downwards. [10] Carrier cassette according to one of claims 1 to 7, comprising two lower support rods (60a, 60b) mounted between the two opposite side plates (52, 54), each of which delimits one of the two receiving areas downwards. [11] Carrier cassette according to one of claims 1 to 10, wherein the at least two lateral support rods (62, 64) and / or the at least one lower support rod (60, 60a, 60b) have projections (80, 80a, 80b) which are designed to separate adjacent wafers (W1 - W5) from one another in the first direction. [12] Carrier cassette according to claim 9, wherein the at least one lower support rod (60, 60a, 60b) has projections (80a, 80b) which are designed to separate adjacent wafers (W1 - W5) of both rows from each other in the first direction. [13] Carrier cassette according to one of claims 1 to 12, wherein a dimension of the two receiving areas in one direction between the at least one lower holding rod (60, 60a, 60b) and the locking rod (70, 70a) is twice as large as a dimension of the two receiving areas in the second direction. [14] Carrier cassette according to one of claims 1 to 13, which has a plurality of upper locking bars (70, 70a), wherein the side plates (52, 54) each have a plurality of locking grooves (56, 56a, 58, 58a), wherein the side plates (52, 54), the at least one lower holding bar (60, 60a, 60b), the at least two lateral holding bars (62, 64) and the plurality of upper locking bars (70, 70a) delimit more than two receiving areas for more than two rows of wafers (W1 - W5) extending in the first direction, wherein the more than two receiving areas are arranged next to one another in the second direction, and wherein each of the upper locking bars (70, 70a) is designed to hold down two rows of wafers adjacent in the second direction, and has projections (72a, 72b) which are designed to to separate adjacent wafers (W1 - W5) of the two rows from each other in the first direction when the upper locking bar (70, 70a) is in two respective ones of the locking grooves (56, 56a,58, 58a) is locked., [15] Carrier cassette according to one of claims 1 to 14, wherein the respective projections (72, 72a - 72d, 80, 80a, 80b, 92a, 92b) are designed to position rows of wafers (W1 - W5) of a thickness ≤ 160 µm, preferably ≤ 100 µm, with a distance ≤ 7 mm, preferably ≤ 5 mm, between wafers (W1 - W5) in the first direction in the receiving areas. [16] Carrier cassette according to one of claims 1 to 15, wherein the side plates (52, 54) have on the upper side receiving means (12) for mechanical handling of the carrier cassette. [17] A method of using a carrier cassette according to any one of claims 1 to 16, wherein two rows of wafers (W1 - W5) are placed side by side in the carrier cassette. [18] Method for treating wafers (W1 - W5) with a treatment liquid using a carrier cassette according to one of claims 1 to 16, comprising the following steps: Placing two rows of wafers (W1 - W5) next to each other in the carrier cassette; Locking the upper locking bar (70, 70a) in the locking grooves (56, 56a, 58, 58a) in order to hold down the two rows of wafers (W1 - W5) with the locking bar (70, 70a); Placing the carrier cassette with the wafers (W1 - W5) into a bath containing the treatment liquid in order to subject the wafers (W1 - W5) to treatment with the treatment liquid.

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