Glass substrate, intended for use in the microelectronics field

Abstract

Glass substrate, intended for use in the microelectronics field Glass substrate (100), intended for use in the microelectronics field, the glass substrate (100) comprising a first main face (110) and a second main face (120). The first main face (110) and / or the second main face (120) have a transparent central zone and an opaque periphery (111, 121). The second main face (120) can be covered by a stack comprising a first layer (140) of a transparent conductive oxide, preferably indium tin oxide, and a second layer (150) of a dielectric material, preferably a silicon nitride layer or a TEOS layer. The first main face (110) can be covered by a substrate of interest (300). Figure for abstract: Fig. 6A

Description

Title of the invention: Glass substrate, intended for use in the microelectronic field Technical field

[0001] The present description relates generally to glass substrates used in the microelectronics industry. Prior art

[0002] It is sometimes necessary to manufacture certain components to use a glass plate as a support instead of a standard silicon plate.

[0003] However, the use of transparent glass plates in conventional microelectronic equipment has several drawbacks.

[0004] Firstly, the supports must be opaque in order to be detected by the optical presence or alignment sensors. Indeed, in such equipment, the substrate is positioned between a light radiation source 20 and a sensor 21, for example a CCD type sensor. The non-transparent silicon substrates 11 are detected because they prevent the transmission of the light radiation from the source 20 to the sensor 21 ([Fig. 1 ]). On the other hand, the light radiation passes through the transparent glass substrates 12, and is transmitted from the source 20 to the sensor 21 ([Fig. 2]). The glass substrates 12 are therefore not detected in this equipment.

[0005] The alignment of the silicon plates can be done thanks to the presence of a notch of approximately 2 mm width on the edge of the plate. The plate is rotated, only the notch lets the radiation pass and thus allows the plates to be aligned. In the case of a transparent plate, the notch is not detected, the plate cannot be aligned.

[0006] Another disadvantage is that the electrical conductivity of the back side of the substrate must be sufficient to allow the plates to be held on the electrostatic clamps ('chuck'). However, the electrical conductivity of glass substrates is not sufficient.

[0007] To overcome these various drawbacks, it is possible to form a conductive layer 13 (metallic or semi-conductive) on the rear face of the transparent substrates 12 not only to make them opacified but also to increase their electrical conductivity on the rear face ([Fig.3A]). Thus, the light radiation does not pass through the substrate 12. The layer 13 can be removed at the end of the process.

[0008] However, this conductive layer 13 must be resistant to the chemicals used to clean the rear face of the plates 12.

[0009] One solution is to encapsulate layer 13 with an additional layer 14 ( [Fig.3A]) to protect it from cleaning chemicals and to limit or even avoid metallic contamination.

[0010] For example, in the article by Zhang et al. ("Enabling Glass Wafers in a Si Fab." 2022 33rd Annual SEMI Advanced Semiconductor Manufacturing Conference (ASMC), 2022, pp. 1-4, doi: 10.1109 / ASMC54647.2022.9792475), the authors used glass substrates covered either by a titanium deposit followed by a SiNx encapsulation layer or by a stack comprising an amorphous silicon (a-Si) layer, a SiO2 layer, a nanocrystalline silicon (ne-Si) layer and then a SiNx layer.

[0011] However, the authors indicate that the Si-based multilayer coating shows insufficient opacity at wavelengths used in chemical mechanical polishing (CMP) machines.

[0012] Furthermore, they add that, although the 100 nm thick SiNx coating can effectively prevent the diffusion of unwanted metallic elements at an operating temperature of 450°C, further research needs to be done to find coatings capable of withstanding higher operating temperatures, such as temperatures above 900°C.

[0013] Furthermore, it should be emphasized that, under certain manufacturing process conditions, the encapsulation of the conductive layer 13 by a dielectric layer 14 may be insufficient to protect it from cleaning chemicals, in particular at the edge of the plates (dielectric layer too thin and therefore not very resistant). When the coating is damaged at the edges, the incident radiation can pass through the substrate 12 at the edges and the latter is no longer detected by the machine ([Fig.3B]). Summary of the invention

[0014] There is a need to at least partially overcome the drawbacks of the prior art and to obtain a glass substrate usable in equipment in the microelectronics industry.

[0015] This aim is achieved by a glass substrate, intended for use in the microelectronic field, the glass substrate comprising a first main face and a second main face, the first main face and / or the second main face having a transparent central zone and an opaque periphery.

[0016] According to a particular embodiment, the opaque perimeter of the first main face and / or the opaque perimeter of the second main face have a width of at least 0.5 mm, preferably at least 2 mm, and even more preferably between 2 and 8 mm.

[0017] According to a particular embodiment, the opaque periphery of the first main face and / or the opaque periphery of the second main face have a roughness between 100 nm and 100 nm, preferably between 400 nm and 3 pm.

[0018] According to a particular embodiment, the opaque periphery of the first main face and / or the opaque periphery of the second main face form a notch, preferably with a depth of between 400 nm and 50 pm, relative to the central zone.

[0019] According to a particular embodiment, the second main face is covered by a stack comprising a first layer of transparent conductive oxide, preferably indium tin oxide, and a second layer of a dielectric material, preferably a layer of silicon nitride or a layer of TEOS.

[0020] According to a particular embodiment, the first main face is covered by a substrate of interest, the substrate of interest comprising microelectronic components, for example emissive microelectronic components, and / or the substrate of interest being bonded to the glass substrate by means of a photosensitive layer.

[0021] This object is also achieved by a method of manufacturing a glass substrate, intended for use in the microelectronic field, the glass substrate comprising a first main face and a second main face, the method comprising a step during which an opaque perimeter is formed on the first main face and / or on the second main face, whereby the first main face and / or the second main face of the substrate have a transparent central zone and an opaque perimeter.

[0022] According to a particular embodiment, the opaque periphery of the first main face and / or the opaque periphery of the second main face are produced by lapping, sandblasting or chemical attack.

[0023] According to a particular embodiment, the method comprises the following steps: - Bonding a substrate of interest to the first main face of the glass substrate, the substrate of interest being able to comprise microelectronic components, for example emissive microelectronic components, and / or the substrate of interest being able to be bonded to the glass substrate by means of a photosensitive element, - Cutting out the substrate of interest, - Forming an opaque edge on the first main face of the glass substrate, by lapping.

[0024] This aim is also achieved by a method for detecting a substrate in a machine in the microelectronics industry, the method comprising a step during which the presence or absence of the substrate is determined by means of light radiation emitted by a source and a light radiation detector, the absence of reception of the light radiation by the light radiation detector being linked to the presence of the substrate which blocks the transmission of the light radiation between the source and the light radiation detector, the substrate being a substrate in glass comprising a first main face and a second main face, the first main face and / or the second main face having a transparent central zone and an opaque surround.

[0025] According to a particular embodiment, the second main face is covered by a stack comprising a first layer of a transparent conductive oxide, preferably indium tin oxide, and a second layer of a dielectric material, preferably a layer of silicon nitride or a layer of TEOS.

[0026] According to a particular embodiment, the glass substrate comprises a notch on the opaque periphery and the method further comprises a step during which the glass substrate is rotated in the machine and aligned thanks to the presence of the notch. Brief description of the drawings

[0027] These characteristics and advantages, as well as others, will be explained in detail in the following description of particular embodiments given without limitation in relation to the attached figures among which:

[0028] [Fig.l], previously described, represents, schematically and in three dimensions, a silicon substrate positioned between a source of light radiation and a sensor, according to the prior art;

[0029] [Fig.2], previously described, represents, schematically and in three dimensions, a glass substrate positioned between a source of light radiation and a sensor, according to the prior art;

[0030] [Fig.3A] and [Fig.3B] previously described, represent, schematically and in three dimensions, a glass substrate covered by a stack comprising a metal layer and a dielectric layer, according to the prior art, respectively, before deterioration of the stack and after deterioration of the stack, the substrate being positioned between a source of light radiation and a sensor;

[0031] [Fig.4A], [Fig.4B] and [Fig.4C] represent, schematically and in three dimensions, glass substrates according to different embodiments of the invention;

[0032] [Fig.4D] and [Fig.4E] represent, schematically and, respectively, in top view and in bottom view, the glass substrate of [Fig.4C];

[0033] [Fig. 5] represents, schematically and in three dimensions, a glass substrate covered by a stack on the rear face, according to another embodiment of the invention;

[0034] [Fig.6A] and [Fig.6B] represent, schematically and in three di dimensions, glass substrates, covered by a stack on the rear face and by a substrate of interest on the front face, according to different embodiments of the invention;

[0035] [Fig.7A] and [Fig.7B] represent, schematically and in three dimensions, different steps of a method of transferring and trimming a substrate of interest onto a glass substrate, according to a particular embodiment; and

[0036] [Fig.8A] and [Fig.8B] are photographs obtained using an optical microscope of a glass plate whose edge has been ground, according to a particular embodiment. Description of the embodiments

[0037] The same elements have been designated by the same references in the different figures. In particular, the structural and / or functional elements common to the different embodiments may have the same references and may have identical structural, dimensional and material properties.

[0038] For the sake of clarity, only the steps and elements useful for understanding the embodiments described have been represented and are detailed.

[0039] Unless otherwise specified, when referring to two elements connected to each other, this means directly connected without intermediate elements other than conductors, and when referring to two elements connected (in English "coupled") to each other, this means that these two elements can be connected or be connected by means of one or more other elements.

[0040] In the following description, when reference is made to absolute position qualifiers, such as the terms "front", "back", "top", "bottom", "left", "right", etc., or relative position qualifiers, such as the terms "above", "below", "upper", "lower", etc., or to orientation qualifiers, such as the terms "horizontal", "vertical", etc., reference is made unless otherwise specified to the orientation of the figures.

[0041] Unless otherwise specified, the expressions "about", "approximately", "substantially", and "of the order of" mean to within 10%, preferably to within 5%.

[0042] By "transparent" is meant that an element (here the central zone) has a transmittance greater than or equal to 70%, preferably greater than 85%. By "opaque" is meant that the transmittance is less than 30% and preferably less than 15%.

[0043] Transmittance represents the ratio between the light intensity having passed through a given element (transmitted intensity) and the light intensity arriving at the element (incident intensity) on the visible spectrum. It can be measured by UV-Vis-IR spectrometry. Transmittance on the visible spectrum corresponds to the transmittance for wavelengths typically between 380 and 780 nm.

[0044] As shown in the various figures 4A to 4E, 5, 6A and 6B, 7A and 7B, the glass substrate 100, intended for use in the microelectronic field, comprises a first main face 110 (called the front face) and a second face main face 120 (called rear face). The two main faces 110, 120 are parallel or substantially parallel to each other. The main faces 110, 120 are connected to each other by a side wall.

[0045] The main faces 110, 120 are preferably circular. The diameter of the main faces 110, 120 is between 50 and 500 mm. It is, for example, 100 mm, 200 mm or 300 mm.

[0046] The substrate 100, also called a plate, has a thickness of between 100 μm and 2 mm.

[0047] For example, a 200 mm plate 100 may have a thickness of 500 μm.

[0048] At least one of the first main face 110 or the second main face 120 is locally opacified on its periphery 111, 121.

[0049] According to an alternative embodiment, this is the second main face 120 ([Fig.4A]). The second main face 120 comprises an opacified periphery 121 and a transparent central zone 122.

[0050] According to another embodiment variant, this is the first main face 110 ([Fig.4B]). The first main face 110 comprises an opacified periphery 111 and a transparent central zone 112.

[0051] According to another embodiment variant, the two main faces 110, 120 are locally opacified on their periphery (FIGS. 4C, 4D and 4E). The first main face 110 comprises an opacified periphery 111 and a transparent central zone 112. The second main face 120 comprises an opacified periphery 121 and a transparent central zone 122. Preferably, when the two main faces 110, 120 are locally opacified, the dimensions of the opacified peripheries 111, 121 are identical.

[0052] Thus, the first main face 110 and / or the second main face 120 have a transparent central zone 112, 122 and an opaque perimeter 111, 121.

[0053] For a circular plate, the opaque periphery 111, 121 forms a ring and the central zone 112, 122 forms a disc.

[0054] The opacification of the edge of the glass substrate 100 makes it possible to create a sufficiently opaque area so that the incident light radiation does not pass through it. Thus, in a machine conventionally used in microelectronics, the light radiation emitted by the source 220 (or the fraction of light radiation necessary for detection) does not reach the sensor 210. The glass substrate 100 is thus easily detected and it can be easily positioned within the machine in order to implement various steps (for example, deposition, photolithography, etching, characterization steps, etc.). The substrate 100 can be aligned thanks to the detection of the notch.

[0055] Only the perimeter 111, 121 is opaque. The central zone 112, 122 remains transparent.

[0056] This is particularly advantageous because it allows, if necessary, to observe possible defects and / or to check the optical properties of the components (emissive component or sensor) through the glass substrate 100. Such control is sometimes necessary during the manufacturing process of the final device. In addition, when the central area is transparent, the substrate can be part of the final optical component.

[0057] The opacification located on the periphery 111, 121 of the substrate 100 also makes it possible to activate the components by photoluminescence through the plate 100.

[0058] It is also possible to crosslink a photosensitive element (glue or resin) through the substrate 100. This may be, for example, an element photocrosslinkable by ultraviolet radiation.

[0059] With a transparent substrate 100, it is also possible to implement laser lift-off processes.

[0060] The width L of the opaque perimeter is preferably at least 0.5 mm. It may be at least 2 mm. For example, the width L is between 2 and 8 mm, and preferably between 2 and 6 mm. As an indication, the typical width of a notch is generally between 1 and 1.2 mm.

[0061] In the case where the substrate of interest is cut out, it no longer includes a notch. If the glass substrate has a notch, this will not be covered.

[0062] In the case where the glass substrate 100 is covered by a substrate of interest 300, of the same dimension, the substrate of interest 300 having a notch on its periphery (for example a silicon substrate), such dimensions make it possible to cover the notch.

[0063] According to another alternative, if the substrate of interest 300 has the same dimension as the glass substrate 100 and if they both have a notch, these will advantageously be aligned.

[0064] Preferably, the width L of the opacified part is identical from one face to the other.

[0065] The opacified portion 111, 121 has a roughness greater than the roughness of the non-opacified portion. For example, the opacified portion 111, 121 has a roughness of at least 100 nm or even at least 400 nm. Preferably, the opacified portion 111, 121 has a roughness of between 100 nm and 10 pm, preferably between 100 nm and 5 pm, and even more preferably between 400 nm and 3 pm. Such roughnesses facilitate the diffusion of visible light radiation.

[0066] Roughness can be measured with a mechanical profilometer. It could also be measured with an atomic force microscope (AFM).

[0067] The thickness of the glass substrate 100 at the opacified portion(s) 111, 121 is less than the thickness of the glass substrate 100 at the central portions 112, 122.

[0068] Indeed, opacification is typically achieved by chemical attack or action mechanical properties of the substrate, which leads to a loss of material at the opacified area 111, 121. The thickness h removed can be at least 400 nm. It can go up to 30 pm or even 50 pm depending on the thickness of the substrate. It is for example approximately 15 pm. For example, a thickness h of 10 pm can be adapted, in particular to a glass substrate with a diameter of 200 mm.

[0069] This variation in thickness is sufficiently small so as not to deteriorate the mechanical properties of the substrate 100.

[0070] Chemical attack is, for example, an attack with a solution containing fluorides. This may be a hydrofluoric acid solution or ammonium fluoride.

[0071] Opacification by mechanical action is, for example, obtained by grinding or by sandblasting or abrading. A mask can advantageously be used to define the perimeter to be opacified and to protect the central zone 112, 122.

[0072] According to a particular embodiment, the glass substrate 100 may have a notch allowing the substrate 100 to be aligned in the microelectronic machines.

[0073] The second main face 120 (rear face) is preferably covered by a stack comprising a first electrically conductive and transparent layer 140 and a second transparent dielectric layer 150 (FIGS. 5, 6A and 6B).

[0074] The first layer 140 is preferably made of transparent conductive oxide (or TCO for 'Transparent Conductive Oxide'). In particular, it may be indium-tin oxide (or ITO for 'Indium Tin Oxide'). Preferably, the first layer 140 completely covers the rear face 120 of the substrate 100.

[0075] The thickness of the TCO is chosen so as to allow the evacuation of charges. The TCO has, for example, a thickness of 100nm.

[0076] Alternatively, the first layer 140 could partially cover the rear face 120 of the substrate 100, for example it could be a layer 140 in the form of a grid.

[0077] The first layer 140 is covered by a second layer 150 which acts as a protective layer. The second layer 150 protects the first layer 140 from the external environment and in particular from the various solutions which may be used during the process.

[0078] In particular, the protective layer 150 is made of a dielectric material, such as tetraethyl orthosilicate (TEOS) or a nitride, preferably a silicon nitride. This layer can be deposited by plasma-enhanced chemical vapor deposition (or PECVD for 'Plasma-Enhanced Chemical Vapor Deposition').

[0079] The protective layer 150 has, for example, a thickness of 300nm.

[0080] The second protective layer 150 is also transparent.

[0081] The stack is transparent.

[0082] Preferably, the coating comprises a first layer 140 of ITO and a second layer 150 of SiN.

[0083] Thus, the substrate 100 can be used in machines of the microelectronics industry, and in particular it is compatible with electrostatic clamps ('chucks').

[0084] Unlike prior art devices, the stack is transparent and the transparency in the center of the substrate is preserved. Only the edges are opaque.

[0085] When the rear face 120 of the substrate 100 is covered by the stack described above, the opacified periphery 111, 121 may be on the front face 110 and / or on the rear face 120.

[0086] An opacification of the edges 111 of the front face 110 is particularly interesting in the case where at least one of the layers 140, 150 of the stack is not deposited in a conforming manner.

[0087] A substrate of interest 300 can be transferred to the front face 110.

[0088] The reported substrate of interest 300 may comprise components 310. These may be emissive components and / or passive components.

[0089] According to one embodiment, the substrate of interest 300 is transferred onto the first main face 110 (front face) of the glass substrate 100 and the second main face 120 (rear face) of the glass substrate 100 is covered by the stack formed from the first layer 140 and the second layer 150 (FIGS. 6A and 6B). The opacified periphery 111, 121 may be on the first main face 110 and / or on the second main face 120.

[0090] The substrate of interest 300 can be assembled to the glass substrate 100 by means of a photosensitive element 400. It can be, for example, a resin photo-crosslinkable under ultraviolet radiation.

[0091] The opacification can be carried out before or after the transfer of the substrate of interest 300. Preferably, it is carried out after.

[0092] The substrate of interest 300 can be trimmed once it has been transferred onto the glass substrate 100. This is particularly interesting for removing possible defects at the edge of the plate.

[0093] The trimming of the substrate of interest 300 and the opacification of the edge 111 of the plate 100 can be carried out by grinding. These steps can be carried out consecutively or simultaneously. Preferably, the grinding step is followed by the opacification step.

[0094] For example, as shown in Figures 7A and 7B, the method may comprise the following steps: i) Bonding a substrate of interest 300 to the first main face 110 of the glass substrate 100, the substrate of interest 300 being able to comprise microelectronic components 310 (for example emissive microelectronic components) and / or the substrate of interest being able to be bonded to the glass substrate 100 by means of a photosensitive layer 400, ii) Cut out the substrate of interest 300, iii) Forming an opaque edge 111 on the first main face 110 of the substrate 100, by lapping.

[0095] The steps are advantageously carried out in the following order: i), ii) and iii).

[0096] Nevertheless, it would be possible to carry them out in one of the following orders: iii), i) and ii) or ii), iii) and i) or iii), ii) and i).

[0097] The glass substrate described above can be used in machines in the microelectronics industry. The method for detecting a substrate in such a machine comprises a step during which the presence or absence of the substrate is determined by means of light radiation emitted by a source 220 and a light radiation detector 210. The source is for example an LED.

[0098] The reception of the light radiation by the light radiation detector 210 is linked to the absence of the substrate: the light radiation is transmitted directly between the source 220 and the light radiation detector 210.

[0099] The absence of reception of the light radiation by the light radiation detector 210 is linked to the presence of the substrate which blocks the transmission of the light radiation between the source 220 and the light radiation detector 210.

[0100] Once detected, the glass substrate 100 can be aligned in the machine.

[0101] The detection of the substrate 100 by the edge can also allow its centering in the machine relative to a desired position, for example on the electrostatic clamps ('chuck').

[0102] In addition, the detection of the notch makes it possible to align the substrates during the process. To do this, the substrate, located in an alignment module internal to the machine, is rotated. Once detected and centered, the detection of the presence of the notch makes it possible to align it in the machine and thus define its position for the rest of the process.

[0103] Illustrative and non-limiting example of a particular embodiment

[0104] The edge of a circular glass plate has been ground ('grinding'). The plate includes a notch.

[0105] The plate was observed under an optical microscope (Figures 8A and 8B). The lapped part is clearly visible. The notch does not protrude from the lapped part. Profilometry measurements were carried out with a mechanical profilometer. The average roughness Ra is 1.54 pm and the root mean square roughness Rq is 1.96 pm.

[0106] Various embodiments and variations have been described. Those skilled in the art will understand that certain features of these various embodiments and variations could be combined, and other variations will occur to those skilled in the art.

[0107] Finally, the practical implementation of the embodiments and variants described is within the reach of those skilled in the art from the functional indications given above.

Claims

Claims

1. Glass substrate (100), intended for use in the microelectronic field, the glass substrate (100) comprising a first main face (110) and a second main face (120), characterized in that the first main face (110) and / or the second main face (120) have a transparent central zone (112, 122) and an opaque periphery (111, 121).

2. Substrate according to claim 1, characterized in that the opaque periphery (111) of the first main face (110) and / or the opaque periphery (121) of the second main face (120) have a width of at least 0.5 mm, preferably at least 2 mm, and even more preferably between 2 and 8 mm.

3. Substrate according to one of claims 1 and 2, characterized in that the opaque periphery (111) of the first main face (110) and / or the opaque periphery (121) of the second main face (120) have a roughness of between 100 nm and 100 nm, preferably between 400 nm and 3 pm.

4. Substrate according to any one of the preceding claims, characterized in that the opaque periphery (111) of the first main face (110) and / or the opaque periphery (121) of the second main face (120) form a detachment, preferably with a depth of between 400 nm and 50 pm, relative to the central zone (112, 122).

5. Substrate according to any one of the preceding claims, characterized in that the second main face (120) is covered by a stack comprising a first layer (140) of transparent conductive oxide, preferably indium tin oxide, and a second layer (150) of a dielectric material, preferably a layer of silicon nitride or a layer of TEOS.

6. Substrate according to any one of the preceding claims, characterized in that the first main face (110) is covered by a substrate of interest (300), the substrate of interest (300) comprising microelectronic components (310), for example emissive microelectronic components, and / or the substrate of interest (300) being bonded to the glass substrate (100) by means of a photosensitive layer (400).

7. A method of manufacturing a glass substrate (100), intended for use in the microelectronic field, the glass substrate (100) comprising a first main face (110) and a second main face (120), the method comprising a step during which an opaque perimeter (111, 121) is formed on the first main face (110) and / or on the second main face (120), whereby the first main face (110) and / or the second main face (120) of the substrate (100) have a transparent central zone (112, 122) and an opaque perimeter (111, 121).

8. Method according to claim 7, characterized in that the opaque periphery (111) of the first main face (110) and / or the opaque periphery (121) of the second main face (120) are produced by lapping, sandblasting or chemical attack.

9. Method according to one of claims 7 and 8, characterized in that the method comprises the following steps: - Bonding a substrate of interest (300) on the first main face (110) of the glass substrate (100), the substrate of interest (300) being able to comprise microelectronic components (310), for example emissive microelectronic components, and / or the substrate of interest (300) being able to be bonded to the glass substrate (100) by means of a photosensitive element (400), - Cutting out the substrate of interest (300), - Forming an opaque periphery (111) on the first main face (110) of the glass substrate (100), by lapping.

10. A method of detecting a substrate in a machine in the microelectronics industry, the method comprising a step during which the presence or absence of the substrate is determined by means of light radiation emitted by a source (220) and a light radiation detector (210), the absence of reception of the light radiation by the light radiation detector (210) being linked to the presence of the substrate which blocks the transmission of the light radiation between the source (220) and the light radiation detector (210), characterized in that the substrate is a glass substrate (100) comprising a first main face (110) and a second main face (120), the first main face (110) and / or the second main face (120) having a transparent central zone (112, 122) and an opaque periphery (111, 121).

11. Method according to claim 10, characterized in that the second main face (120) is covered by a stack comprising a first layer (140) of a transparent conductive oxide, preferably indium tin oxide, and a second layer (150) of a dielectric material, preferably a layer of silicon nitride or a layer of TEOS.

12. Method according to one of claims 10 and 11, characterized in that the glass substrate (100) comprises a notch on the opaque periphery (111, 121) and in that the method further comprises a step during which the glass substrate (100) is rotated in the machine and aligned thanks to the presence of the notch.

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