Methods for manufacturing hollow walls for controlling the directional deposition of materials

Abstract

A method for fabricating a hollow wall for controlling the directional deposition of material includes: forming a layer of photoresist on a substrate; selectively removing a portion of the photoresist to form a channel within the photoresist; forming an amorphous dielectric material layer within the channel; and removing the photoresist to form a hollow wall. The channel has a front surface configured to prevent bending of a corresponding front surface of the hollow wall. For example, hollow walls can be used to control material deposition in the fabrication of semiconductor-superconductor hybrid devices. By appropriately constructing the channel, bending of the hollow wall can be prevented, thereby allowing for more precise material deposition. Another method for fabricating a hollow wall is also provided; and a method for fabricating a device using a hollow wall.

Description

Background Technology

[0001] Directional deposition processes such as molecular beam epitaxy are techniques that have been used to grow materials on substrates.

[0002] Selective region growth is a technique for forming nanostructures of controlled shapes in controlled locations by applying a patterned amorphous mask to a substrate and performing molecular beam epitaxy. Various other growth techniques, such as metal-organic vapor phase epitaxy, can be used in a similar manner.

[0003] Molecular beam epitaxy (MBE) is a method for depositing thin film single crystals onto a substrate. The method involves heating the material to be deposited, causing it to enter the gas phase, thereby generating a beam that, when directed onto the substrate, causes the material to condense onto the substrate. This method is performed at very low pressures: the evaporated atoms have long mean free paths, preventing them from interacting before reaching the substrate. Summary of the Invention

[0004] This article provides a method for fabricating a hollow wall for controlling the directional deposition of a material. The method includes: forming a layer of photoresist on a substrate; selectively removing a portion of the photoresist to form a channel within the photoresist; forming an amorphous dielectric material layer within the channel; and removing the photoresist to form a hollow wall. The channel has a front surface configured to prevent bending of the corresponding front surface of the hollow wall.

[0005] A method for manufacturing a hollow wall for controlling the directional deposition of a material is also provided. The method includes: forming a layer of photoresist on a substrate; selectively removing a portion of the photoresist to form a channel within the photoresist; depositing an amorphous dielectric material layer within the channel; and removing the photoresist to form a hollow wall. The channel includes a first surface and a second surface. The channel includes a protrusion disposed at a corner between the first and second surfaces, the protrusion being configured to prevent deformation of the corresponding corner of the hollow wall.

[0006] A method for manufacturing a device is also provided. The method includes fabricating a hollow wall using the method provided herein; and selectively depositing material over a substrate using a beam. The beam is directed toward the substrate in a selected direction so that the hollow wall prevents material from depositing in shadowed areas created by the hollow wall.

[0007] This summary is provided to introduce, in a simplified form, a series of concepts that will be further described in the detailed description below. This summary is not intended to highlight key or essential features of the claimed subject matter, nor is it intended to limit the scope of the claimed subject matter. The claimed subject matter is also not limited to embodiments that address any or all of the shortcomings mentioned herein. Attached Figure Description

[0008] To aid in understanding the embodiments of this disclosure and to illustrate how these embodiments can be implemented, reference is made to the accompanying drawings, which are provided by way of example only, wherein:

[0009] Figure 1 It is a flowchart outlining the method for manufacturing hollow walls;

[0010] Figures 2a to 2d Is Figure 1 A series of schematic cross-sections of the product obtained in each step of the method;

[0011] Figure 3 These are scanning electron microscope (SEM) images of devices fabricated using hollow walls according to comparative examples, with annotations showing bending, deformation, and their effects;

[0012] Figure 4a yes Figure 3 The enlarged portion shows the curvature of the hollow wall surface;

[0013] Figure 4b yes Figure 3 The magnified portion shows the deformation of the corner of the hollow wall;

[0014] Figure 5a It is a schematic plan view of the channel used to form the hollow wall according to the comparative example;

[0015] Figure 5b Is it used as in Figure 5a The image shows a SEM micrograph of the hollow wall obtained from the channel shown in the image.

[0016] Figure 6a This is a schematic plan view of a channel for forming a hollow wall according to a first example of this disclosure, labeled to illustrate a technique for determining the curvature;

[0017] Figure 6b Is it as in Figure 6a The schematic plan view of the channel shown is labeled to illustrate alternative techniques used to determine the bend;

[0018] Figure 6c Is it used as in Figure 6a The image shows a SEM micrograph of the hollow wall obtained from the channel shown in the image.

[0019] Figure 7 It is a schematic plan view of the channel used to form the hollow wall according to the second example;

[0020] Figure 8 It is a schematic plan view of the channel used to form the hollow wall according to the third example;

[0021] Figure 9It is a schematic plan view of part of a channel constructed to reduce corner deformation of the hollow wall;

[0022] Figure 10 It is a flowchart outlining a method for manufacturing devices using hollow walls;

[0023] Figure 11 This is a schematic plan view of an example arrangement of hollow walls used to control material deposition;

[0024] Figure 12 Is it used as in Figure 11 The image shows a SEM micrograph of the device after aluminum deposition, illustrating the arrangement of hollow walls.

[0025] It should be understood that, in the schematic diagram, the angles and / or relative proportions of the components may be exaggerated for clarity. Detailed Implementation

[0026] As used herein, the verb “includes” is used as a shorthand for “includes or constitutes.” In other words, while the verb “includes” is intended to be an open-ended term, it is explicitly considered that the closed-ended term “consisting of” should be used instead, especially in cases relating to chemical compositions.

[0027] For ease of description, this document uses directional terms such as “top,” “bottom,” “left,” “right,” “up,” “down,” “horizontal,” and “vertical” to refer to the orientation shown in the figures. To avoid any ambiguity, these terms are not intended to limit the orientation of the device within an external reference frame.

[0028] In the context of this disclosure, "front" refers to the face of the hollow wall facing the area to be patterned. In other words, the front is close to the area to be patterned. Figure 3 Box A in the middle corresponds to the part in front.

[0029] As used herein, the term "superconductor material" refers to a material that becomes superconducting when cooled to a temperature below its critical temperature Tc. The use of this term is not intended to limit the temperature during the manufacturing process.

[0030] The term "nanowire" as used herein refers to an elongated structure having a width on the nanometer scale and an aspect ratio of at least 10, at least 50, or at least 100. Typical examples of nanowires have widths ranging from 10 nm to 500 nm, optionally from 50 nm to 100 nm or 75 nm to 125 nm. Lengths are typically on the micrometer scale, for example, at least 1 μm or at least 10 μm. In this context, nanowires are typically formed from semiconductor materials.

[0031] Geometric terms are used for convenience of description. The term "substantially rectangular" refers to a shape based on a rectangle but including modified shapes such as chamfers at one or more corners, bends or serrations in one or more sides, etc. The term "substantially triangular" refers to a shape based on a triangle but including modified shapes such as serrations in one or more sides or protrusions extending from one or more corners, etc.

[0032] The content of all documents cited herein is hereby incorporated herein by reference in its entirety.

[0033] Hollow walls can be used to selectively deposit materials using methods involving the use of directed beam deposition of materials. The hollow walls block the beam, creating a "shadow" in which no material is deposited. Since the walls are thin, they can be easily removed after the deposition process. A method for forming hollow walls is described in co-pending U.S. Patent Application No. 16 / 258,025, the content of which is incorporated herein by reference.

[0034] Reference will now be made Figure 1 to FIG. 2 and describe a method of fabricating hollow walls for controlling material deposition.

[0035] At block 101, a resist layer 14 is formed on a substrate 10. A schematic cross-section of the product of this block is shown in Figure 2a .

[0036] In the context of the present disclosure, a "substrate" can be any structure on which a hollow wall is to be constructed. Generally, the substrate includes a wafer of semiconductor material. The substrate can include other structures disposed above the wafer. The substrate can include multiple layers of materials. The substrate can include nanowires of semiconductor material disposed on the wafer.

[0037] Any semiconductor material can be used. Schematic examples of semiconductor materials include III-V semiconductors, especially those of formula I:

[0038] (1)InAs ,

[0039] , ,

[0038] , x ,

[0040] , <​​​​​​​Indium arsenide (InAs) has been found to have good processing properties. Indium antimonide (InSb) can provide improved performance for some devices. Ternary mixtures exhibit properties between those of the binary compound InAs and InSb. Values ​​of x in the range of 0.35 to 0.8 can provide special advantages for some applications.

[0041] Specifically, the material of Formula 1 can be arranged as nanowires.

[0042] One example wafer material is indium phosphide, a high-bandgap semiconductor. Other examples include gallium arsenide, indium antimonide, and silicon.

[0043] There are no particular restrictions on the type of photoresist, as long as it is compatible with the technology to be used. Photoresists are typically electron beam photoresists. Photoresists are well-known in the semiconductor manufacturing industry.

[0044] The resist layer 14 has a depth. Controlling the depth of the resist layer 14 allows for control over the height of the resulting hollow wall. The depth of the resist layer can be, for example, in the range of 0.5 μm to 2 μm.

[0045] A useful technique for forming the resist layer 14 is spin coating. Spin coating allows for uniform application of the resist to achieve substantially equal depths on the surface of the substrate 10. Spin coating also allows for good control over the thickness of the resist layer 14. The thickness can be controlled by selecting the number of spin coating cycles.

[0046] At box 102, a portion of the resist is selectively removed to form a channel within the resist. The result of this step is as shown in... Figure 2b As shown in the image.

[0047] This step removes a portion of the resist layer 14 to form a partial resist layer over the wafer 10. The partial resist layer 14 defines a channel 15. A region 10a of the surface of the substrate 10 is exposed in the channel 15. The channel 15 is defined by an inner surface 14b of the partial resist layer 14, which extends from the surface of the substrate 10 to the top surface 14a of the resist layer 14.

[0048] The shape and position of channel 15 determine the shape and position of the hollow wall 18 to be manufactured by this method.

[0049] Photolithography can be used to selectively remove resist. In an example where the resist includes an electron beam resist, a portion of the resist layer 14 is exposed to an electron beam. The electron beam alters the solubility of the resist in the resist developer.

[0050] The photoresist can be a positive or negative photoresist. With a positive photoresist, the areas to be removed are exposed to an electron beam, making these areas soluble in the developer. With a negative photoresist, areas of the photoresist 14 that will not be removed are exposed to an electron beam, making the photoresist 14 in these areas insoluble in the developer.

[0051] After the resist 14 has been exposed to the electron beam, it is developed using a resist developer.

[0052] Photoresists and suitable developers are known in the semiconductor manufacturing industry.

[0053] Although this example has been explained with reference to electron beam resist, the technique for selectively removing the resist can be appropriately selected depending on the type of resist. Some resists can be developed using other techniques, such as exposure to light with a specific wavelength.

[0054] Any residual resist remaining in channel 15 after the removal step can be removed using slag removal processes known in the art.

[0055] Figure 2b The illustration shows the case where only a portion of the resist layer 14 is removed. For some applications, removing multiple portions of the resist layer 14 is useful because it allows for the formation of multiple hollow walls. As will be explained later, the use of multiple hollow walls can be used for fine control of material deposition.

[0056] At frame 130, an amorphous dielectric material layer 16 is formed on the surface of the substrate to obtain the effect shown in the figure. Figure 2c The structure shown in the figure.

[0057] Amorphous dielectric materials will form walls. Examples of useful amorphous dielectric materials include silicon nitride and silicon oxide, especially silicon nitride.

[0058] The thickness of the amorphous dielectric material layer 16 will determine the thickness of the hollow wall 18. This thickness is typically in the range of 30 nm to 300 nm, for example, 30 nm to 100 nm. In the methods of this disclosure, selected portions of the layer may have a smaller thickness, less than 30 nm, which will be explained further below.

[0059] Forming the amorphous dielectric layer 16 may include directly depositing the amorphous dielectric material. Alternatively, a precursor may be deposited, followed by a reaction to form the amorphous dielectric material in situ. One type of precursor used for in-situ formation of silicon oxide is hydrogen silsesquioxane (HSQ). HSQ can be converted in situ into silicon oxide by exposure to an electron beam or electromagnetic radiation of a suitably selected wavelength.

[0060] Amorphous dielectric materials or their precursors are typically deposited non-directionally. An example technique for non-directional deposition of amorphous dielectric materials is magnetron sputtering.

[0061] The amorphous dielectric material layer 16 covers the exposed portion 10a of the substrate 10 in the channel 15 and the side surfaces 14a, 14b of the resist that define the channel 15.

[0062] In this example, the amorphous dielectric material layer 16 also covers the top surface 14a of the resist layer 14. In a subsequent step, a portion of the layer covering the top surface of the resist layer 14 is removed.

[0063] Figure 2c An amorphous dielectric material layer 16 with a substantially uniform thickness is shown above the side surface of the resist layer 14 and on the exposed surface of the substrate 10 within the cavity 15. In a variation, the thickness of the wall material layer is not necessarily uniform. Non-uniform layers can still be used to create usable hollow walls.

[0064] This example uses a single layer of amorphous dielectric material. In a variation, two or more layers of different materials can be formed. This creates hollow walls formed by the composite material. The use of composite materials allows for stress compensation.

[0065] At frame 104, the remaining portion of the resist layer 14 is removed to form a hollow wall 18 disposed on the substrate 10.

[0066] Any amorphous dielectric material deposited on the top surface of the resist 14 is removed along with the resist 14. This then leaves the hollow shadow wall 13 located at the channel 15.

[0067] The hollow wall 18 includes a base 18a and a side 18b. The base 18a is formed from the wall material in the area 10a of the previously left (now removed) partially exposed resist layer 14, and the side 18b is formed from the amorphous dielectric material of the inner surface 14b of the previously partially covered resist layer 14.

[0068] Resist 14 can be removed by stripping, as is known in the art. An example of a stripping solvent is acetone.

[0069] After stripping, plasma cleaning can be performed to remove impurities from the surface of substrate 10. Oxygen plasma treatment can be used. Oxygen plasma treatment can oxidize the surface of silicon nitride to form a silicon oxide coating.

[0070] The inventors have found it challenging to reliably manufacture hollow walls with well-defined geometries. It has been observed that the shape of the channel formed at frame 102 can be controlled very precisely, and this shape can be maintained when an amorphous dielectric material is deposited at frame 103. However, the inventors have found that the shape of the completed hollow wall can deform. This deformation is inconsistent, and the differences between the individual walls result in unique shapes. This makes it more difficult to reliably control the deposition of the material.

[0071] Without being bound by theory, it is believed that the removal of the resist may introduce bending on various surfaces of the wall and deformation at corners. Internal mechanical stress within the wall is considered a contributing factor.

[0072] Figure 3 Figure 4 illustrates the problems discovered by the inventors.

[0073] Figure 3 These are SEM micrographs showing three hollow walls 30, 32, and 34 fabricated from channels with simple block shapes. These walls are formed of silicon nitride and are shown using the reference above. Figure 1 The method described above is used to fabricate hollow walls 30, which are manufactured using simple trapezoidal channels. Hollow walls 32 and 34 are manufactured using conventional triangular channels. Hollow walls 30, 32, and 34 are used to control the deposition of aluminum on nanowires 36.

[0074] The hollow wall 30 has a curved front (region A). Figure 4a The image shown is an enlarged view of this portion of the hollow wall 30. A more pronounced curvature exists on the front of the hollow walls 32 and 34. This curvature creates irregular shadows: the shadows curve in regions 36 and 38 and extend less than the distance required at 40.

[0075] As highlighted at 42, further curvature is observed in the shadow on its side. The inventors believe this is a result of the corner deformation of the hollow walls 32 and 34. One such corner is in region B, and... Figure 4b The image shows a magnified view of this corner. As can be seen, the shape of the corner is distorted.

[0076] Because the shadows don't have the desired shape, aluminum is deposited in unwanted locations. Devices used in quantum computing applications must be manufactured with extremely high precision. Undesirable material deposition can be very detrimental to device performance. In the worst case, the device can short-circuit and become completely unusable. This is a particularly difficult problem when scaling up devices, as the increased size and complexity make it more likely that defects will appear somewhere in the device.

[0077] Figure 5a and Figure 5b Additional illustrations of the bending problem observed by the inventors are provided. Figure 5a A schematic plan view of channel shape 500 is shown, in this case, a basic rectangular shape; and Figure 5b SEM micrographs of the hollow wall 510 obtained using this channel shape are shown. Figure 5b Use line 512 to mark the front shape of the hollow wall 510 more clearly.

[0078] As can be clearly seen, the front of the hollow wall has been bent, causing its shape to deviate significantly from the expected linear shape.

[0079] There is a need to provide a method for manufacturing hollow walls with improved linearity of surfaces.

[0080] Figure 6a and Figure 6b Plan views of a first example of a channel shape 600 according to this disclosure, with different labels, are shown respectively. Figure 6c It shows the use of Figure 6a / Figure 6b The image of the hollow wall obtained from the channel shape.

[0081] Channel 600 has a generally rectangular shape. The front surface 610 of the generally rectangular shape has an outward curve. The degree of curvature is chosen so that when this channel shape is used to form a hollow wall, the corresponding front surface 620 is approximately linear. This avoids the negative impact of the front curvature in the comparative example.

[0082] An interior angle 616 between the midpoint of the generally rectangular front surface 610 and the midpoint of one of the generally rectangular side surfaces 612a, 612b provides a measurement of the amount of curvature. The front surface 610 may have a selected curvature such that the angle is in the range of 96° to 104°, for example 98° to 102° or 99° to 101°. One example has an angle of approximately 100°. Curvature levels within these ranges have been found to be particularly useful for fabricating hollow walls with linear surfaces. This range is particularly suitable when the spacing between the channels in the sidewalls is in the range of 1.8 μm to 2.2 μm.

[0083] The amount of curvature can be adjusted based on the distance between the side surfaces of the rectangle. Longer channels may benefit from greater curvature.

[0084] Now refer to Figure 6b To describe alternative measurements of bending.

[0085] Line 618 is projected perpendicularly from the corner between the side surface 612a and the front surface 610 along the x-direction. The distance of the widest part of the curve from the side surface to the front surface 610 is 0.5s.

[0086] Make the distance p the distance by which the surface deviates from the linear surface at its midpoint; in other words, the distance in the y-direction from the midpoint of the front surface 610 to the line 618.

[0087] The distance p and 0.5s can be related as follows:

[0088]

[0089] Where θ is in the range of 6° to 14°, and can be selected as 8° to 12°, or 9° to 11°, or approximately 10°. This provides the observed degree of curvature, thus giving the wall good linearity, especially when s is in the range of 1.8 μm to 2.2 μm.

[0090] Figure 7 Another example of a channel shape 700 is shown, which has a front surface configured to reduce the curvature of the resulting hollow wall. The channel shape 700 is generally rectangular in shape, with chamfered portions 702, 704 at the corners between the front surface 706 and the side surfaces 708, 710 of the channel.

[0091] In this example, the interior angles 712a and 712b between the side surfaces 708 and 710 and the chamfered portions 702 and 704 are in the range of 96° to 104°. Angles in this range, especially 98° to 102°, 99° to 101°, or about 100°, have been found to be particularly useful in preventing the negative effects associated with bending of the front of the hollow wall.

[0092] The chamfered portion has a length c in the range of 500 nm to 700 nm. In some examples, the non-chamfered portion 707 of the front surface may also have a length in the range of 500 nm to 700 nm. More generally, each of the two chamfered and non-chamfered portions may have equal lengths.

[0093] The spacing s between the side surfaces 708 and 710 of the channel is typically in the range of 1.5 μm to 2.5 μm.

[0094] It has been found that providing a channel shape with an outwardly extending front by providing a chamfer at the corner of the channel reduces the negative impact of the front bending of the hollow wall manufactured using the channel.

[0095] Although this example has been described with reference to specific aspects, the interior angle at the chamfered portion, the length of the chamfered portion, and the relative length of the non-chamfered portion can be adjusted to extend the effect to larger or smaller hollow walls.

[0096] This example is symmetrical and has two chamfered sections. In one variation, one corner is chamfered.

[0097] Figure 8 It shows in Figure 7 The diagram shows a variation of the channel shape. In this example, the corners 850 and 852 between the side surfaces 808 and 810 of the channel and the rear surface 812 are also chamfered. This can allow for improved reproducibility of the sides of the hollow wall fabricated using the channel, which may be advantageous in examples where more than one surface is used to control material deposition.

[0098] In the example that uses only the hollow wall at the front, the construction at the back is not particularly restricted.

[0099] exist Figure 7 and Figure 8 In the example shown, the chamfered portion is typically a straight section. In various variations, the chamfered portion can be curved. In such an example, the interior angle will vary along the arc of the chamfered portion. The relevant measurement of the interior angle is then the measurement of the interior angle between a point on the sidewall and the midpoint of the arc. In this example, the length of the chamfer is measured along the arc.

[0100] Figure 9 A plan view of a portion of the channel is shown, which includes protrusions 910 for preventing deformation of the corners of the hollow wall.

[0101] The protrusion 910 is an extension of the channel located at the corner between the first surface and the second surfaces 902 and 904 of the channel.

[0102] The protrusion can have a length L ranging from 50 nm to 150 nm. For some applications, a length in the range of 70 nm to 100 nm may be preferred. This length typically does not exceed approximately 300 nm, due to the possible observation of increased sensitivity to deformation.

[0103] The protrusion can have a width W in the range of 30nm to 100nm.

[0104] The protrusion is at an angle relative to each of the first and second surfaces of the channel. Angles θ1 and θ2 are the interior angles between the first or second surface and the adjacent surface of the protrusion minus 180°, respectively, and are less than 45°, typically in the range of 20° to 45°.

[0105] By including protrusions with the aforementioned parameters, it has been found that the effects of deformation at the corners of the hollow wall can be reduced.

[0106] The wall portions formed in the raised regions can be thinner than those farther from the raised areas. This is because the narrower regions of the channel receive less material flux during the deposition process of the wall material than the wider portions. For example, the material thickness in the raised regions can be less than 30 nm, while the thickness of a typical wall portion ranges from 30 nm to 100 nm. Without being bound by theory, it is assumed that the reduced amount of material in the raised regions implies less stress accumulation in the material, thus reducing corner deformation.

[0107] Figure 10 This is a flowchart outlining a method for manufacturing a device using the hollow walls of this disclosure.

[0108] At box 1001, use the previous reference. Figure 1 The hollow walls are fabricated on the substrate using the method described in Figure 2. The channels used to form the hollow walls are configured to reduce the curvature of the hollow wall surfaces, as previously shown in Figures 6 to 7. Figure 8 As described; or configured to include protrusions configured to prevent corner deformation of the hollow wall, as referenced. Figure 9 As described.

[0109] Multiple hollow walls can be manufactured. The location and orientation of the hollow walls can be selected as needed, depending on where the material will be deposited. See below for reference. Figure 11 A useful construction with multiple hollow walls is described in more detail.

[0110] In one variation, after the hollow walls are fabricated, additional components are formed or placed on the substrate. Nanowires are an example of such additional components.

[0111] At box 1002, material is selectively deposited onto the substrate using a beam directed toward the substrate in a selected direction, such that the hollow walls prevent material from being deposited in the shadowed areas created by the hollow walls.

[0112] Material is deposited onto a substrate via directional deposition. Shadow walls create shaded areas on the device where no material is deposited. As a result, a pattern of material is formed on the surface of the device.

[0113] Materials can be selected as needed. Examples include superconductors, semiconductors, and dielectrics.

[0114] Various types of directional deposition are known. For example, molecular beam epitaxy or electron gun epitaxy can be used.

[0115] Examples of superconducting materials include aluminum, lead, indium, and tin. These materials can be stored as solids in the source cell and evaporated for projection onto the device. Examples of semiconductor materials include those of Formula 1 as previously defined.

[0116] One or more subsequent depositions can then be performed. The material deposited in the subsequent depositions can be the same as the material deposited in the first deposition, or a different material. In one example, a superconductor can be deposited in the first deposition, and a dielectric can be deposited in the second deposition. The angle of material deposition can be varied with each deposition. By changing the angle, different patterns can be formed on the device using the same hollow walls.

[0117] After the material has been deposited, the sidewalls 13b of the hollow wall 13 can be removed. For some applications where chemical methods may cause damage, mechanical methods such as ultrasonication are preferred. Because the wall is hollow, mechanical removal is easier.

[0118] Removing the wall using ultrasound can involve placing the device in a liquid bath and applying ultrasound. Other mechanical methods can also be used. Generally, thinner walls are easier to remove, but also more fragile.

[0119] After the wall is removed, a thin overlay area may remain on wafer 10 corresponding to the base of the wall. This thin overlay area is generally well tolerated in any subsequent manufacturing steps.

[0120] Figure 11 Figure 6 to 10 are shown. Figure 8 The type of hollow wall described and reference Figure 9 The combination of hollow walls of the described types enables good control over the deposition of material (superconductor material in this example) on the target (selected nanowire in this example).

[0121] The roughly triangular hollow walls 1110 and 1112 have clearly defined point boundaries, thus providing shaded regions 1114a and 1114b with sharp, well-defined edges 1115a and 1115b. The front surfaces of the roughly triangular hollow walls 1110 and 1112 cast shadows on the left-hand and right-hand portions of the nanowire, respectively, ensuring that material is deposited only in selected central regions of the nanowire.

[0122] A rectangular hollow wall 1118 is arranged between and behind triangular hollow walls 1110 and 1112. The rectangular hollow wall 1118 projects a shadow 1114c over the area in front of the hollow wall, almost down to the nanowire. Because the front boundary of the rectangular hollow wall 1118 is clearly defined, the length of the shadow 1114c is precisely controlled. The arrangement of the triangular hollow walls 1110 and 1112 relative to the rectangular hollow wall 1118 helps ensure that the shadow 1114c has clearly defined edges. (As shown in...) Figure 11 As shown, the points of the triangular hollow walls 1110 and 1112 are in front of the rectangular hollow wall 1118.

[0123] Figure 12 It is shown in Figure 11 The image shows a SEM micrograph of the arrangement, which allows for precise control of the shadow edges. The edges are highlighted with dashed lines. As can be seen, the shadows have straight edges, and the edges of the shadows are parallel. The image shows azimuth misalignment. This misalignment is due to a manual cleaving process used during manufacturing, and not any effect of the shadow wall.

[0124] Figure 12 The lower left and lower right sides show the use of including Figure 9 The corners of the shadowed walls are created using channels of the shapes shown. As can be seen, sharp, well-defined corners are achieved. These examples are made using channels with serrated edges. This serrated pattern has been found to reduce the effects of bending. The serrations are described in more detail in co-pending U.S. Patent Application No. 16 / 258,025.

[0125] It should be understood that the above embodiments are described by way of example only.

[0126] More generally, according to one aspect disclosed herein, a method is provided for manufacturing a hollow wall for controlling the directional deposition of a material, the method comprising: forming a layer of photoresist on a substrate; selectively removing a portion of the photoresist to form a channel within the photoresist; forming an amorphous dielectric material layer within the channel; and removing the photoresist to form a hollow wall; wherein the channel has a front surface configured to prevent bending of a corresponding front surface of the hollow wall. The inventors have discovered that the surface of a hollow wall formed on the surface of a linear channel in a plane tends to bend during the manufacturing process. Improved linearity of the wall surface can be achieved by modifying the shape of the channel. For example, configuring the channel to have a convex surface in a plane can counteract the effects of bending.

[0127] Hollow walls can control the directional deposition of materials by blocking the beams of material, thereby defining shaded areas where no material is deposited.

[0128] Forming an amorphous dielectric material layer may include forming the layer in the channel and over the layer of resist. Removing the resist to form a hollow wall may include removing the amorphous dielectric material formed over the resist.

[0129] Amorphous dielectric materials can be silicon nitride or silicon oxide. Amorphous dielectric materials can be formed in situ from suitable precursors, such as HSQ in the case of silicon oxide.

[0130] The channel can have a generally rectangular shape, comprising a front surface, a rear surface opposite the front surface, and a pair of side surfaces. This generally rectangular shape may include a chamfered corner between one of the side surfaces in the front and side surface pair, the chamfered corner having an interior angle with the corresponding side surface, and a chamfer length selected to prevent bending of the front surface of the hollow wall. Providing a channel with a chamfered corner is a useful method for counteracting the effects of bending.

[0131] The chamfer angle can range from 96° to 104°. The chamfer length can range from 400 nm to 800 nm, optionally from 500 nm to 700 nm. The two side surfaces can be spaced apart by a distance ranging from 1.5 μm to 2.5 μm, optionally from 1.8 μm to 2.2 μm. This is an example of a channel shape that has been studied and proven to be able to fabricate hollow walls with front surfaces exhibiting good linearity. The chamfer length and angle can be appropriately adjusted according to the overall dimensions of the hollow wall to be fabricated. Generally, the greater the spacing between the side surfaces, the greater the chamfer angle and / or chamfer length.

[0132] The two corners between the front and side surfaces can be chamfered.

[0133] The roughly rectangular shape can also include corresponding chamfered corners between the side surface and the rear surface in each side surface pair. This can be particularly useful when it is necessary to deposit one or more materials from two or more different directions. In such an example, good control over the geometry of all faces of the hollow wall can be achieved.

[0134] The front surface may have an outward bend selected to prevent the front surface of the hollow wall from bending. In other words, the front surface may have a convex bend in the plane.

[0135] The channel may include a pair of opposing side surfaces at corresponding ends of the front surface, wherein the surface is curved outwards such that the interior angle between the midpoint of the front surface and one of the side surfaces of the opposing side surface pair is in the range of 96° to 104°. In this example, the opposing side surfaces may be spaced apart from each other at a distance in the range of 1.8 μm to 2.2 μm. This combination of curvature and length of the hollow wall has been found to be effective for manufacturing walls with good linearity.

[0136] Selective removal of the resist can form multiple channels in the resist, including a second channel for forming a second hollow wall. The second channel may include a first surface and a second surface. The second channel may include a protrusion disposed at a corner between the first and second surfaces, the protrusion being configured to reduce deformation at the corresponding corner of the second hollow wall.

[0137] Precise control over material deposition can be achieved by forming multiple hollow walls, and especially multiple hollow walls with different shapes. Various combinations of hollow wall shapes and various relative orientations of these shapes can be used to achieve deposition at the desired locations.

[0138] The multiple channels may include: a first channel having a front surface configured to prevent bending of a hollow wall of the type described above, and two second channels arranged on either side of the first channel.

[0139] This configuration allows for shadows with clearly defined lengths and side edges. The second channel can be arranged such that its protrusion is in front of the corner of the first channel to create a shadow with sharp edges.

[0140] On the other hand, a method for manufacturing a hollow wall for controlling the directional deposition of a material is provided, the method comprising: forming a layer of photoresist on a substrate; selectively removing the photoresist to form a channel in the photoresist; depositing an amorphous dielectric material layer in the channel; and removing the photoresist to form a hollow wall. The channel may include a first surface and a second surface. The channel may include a protrusion disposed at a corner between the first and second surfaces, the protrusion being configured to prevent deformation of the corresponding corner of the hollow wall.

[0141] It has been found that sharp corners can be achieved by providing a protrusion at the corner between the two side surfaces. In use, this allows for more precise control over material deposition.

[0142] The protrusion can have a length ranging from 50 nm to 150 nm. The protrusion can form an angle ranging from 20° to 45° relative to the first and second surfaces. Protrusions with these lengths and orientations have been found to be particularly useful.

[0143] The first and second surfaces can be serrated to prevent the corresponding first and second surfaces of the hollow wall from bending.

[0144] The channel can have a roughly triangular shape.

[0145] Another aspect provides a method for manufacturing a device, the method comprising: manufacturing a hollow wall using the method described above; and selectively depositing material over a substrate using a beam. The beam is directed toward the substrate in a selected direction such that the hollow wall prevents material from being deposited in the shadowed areas created by the hollow wall.

[0146] The hollow walls produced by the methods described in this article have well-defined geometries, making them particularly useful for the precise deposition of materials.

[0147] This method may also include removing the hollow wall after deposition.

[0148] Because the walls produced by the methods provided herein are hollow, they may be relatively easy to remove compared to solid walls (i.e., solid blocks of material). Hollow walls can be removed mechanically, for example. One useful technique for the mechanical removal of hollow walls is ultrasonic treatment. For some applications, mechanical methods are preferred over chemical methods because components of some devices may be easily damaged by certain reagents.

[0149] The substrate may include semiconductors. The material may include superconducting materials.

[0150] The techniques disclosed in this paper are particularly useful for constructing semiconductor-superconductor hybrid devices.

[0151] The method may also include forming nanowires on a substrate prior to deposition. Deposition may include selectively depositing material on at least a portion of the nanowires.

[0152] Nanowires are significant for constructing semiconductor-superconductor hybrid devices. The methods described in this paper have been successfully applied to the controlled deposition of superconducting materials on nanowires at selected locations.

[0153] This disclosure provides the following terms:

[0154] Clause 1. A method for manufacturing a hollow wall for controlling the directional deposition of a material, the method comprising:

[0155] A layer of resist is formed on the substrate;

[0156] Selectively remove a portion of the resist to form channels within the resist;

[0157] An amorphous dielectric material layer is formed in the channel; and

[0158] Remove the resist to form a hollow wall;

[0159] The channel has a front surface that is configured to prevent the corresponding front surface of the hollow wall from bending.

[0160] Clause 2. The method according to Clause 1, wherein the channel has a generally rectangular shape, the generally rectangular shape comprising a front surface, a rear surface opposite the front surface, and a pair of side surfaces;

[0161] The generally rectangular shape includes a chamfered corner between one of the side surfaces of the front and side surfaces, the chamfered corner having: an interior angle with the corresponding side surface, and a chamfer length selected to prevent the front surface of the hollow wall from bending.

[0162] Clause 3. The method described in Clause 2, wherein the interior angle is in the range of 96° to 104°.

[0163] Clause 4. The method described in accordance with Clause 2 or Clause 3, wherein the chamfer length is in the range of 400 nm to 800 nm.

[0164] Clause 5. The method according to any one of Clauses 2 to 4, wherein the side surfaces are spaced apart from each other by a distance ranging from 1.5 μm to 2.5 μm.

[0165] Clause 6. The method according to any one of Clauses 2 to 5, wherein the generally rectangular shape further includes a corresponding chamfered corner between each side surface and the rear surface in the side surface pair.

[0166] Clause 7. The method according to Clause 1, wherein the front surface has an outward bend selected to prevent the front surface of the hollow wall from bending.

[0167] Clause 8. The method according to Clause 7, wherein the channel comprises a pair of opposing side surfaces at respective ends of the front surface.

[0168] The outward curvature results in an interior angle between the midpoint of the front surface and one of the opposite side surfaces ranging from 96° to 104°.

[0169] Clause 9. The method according to Clause 8, wherein the opposite side surfaces are spaced apart by a distance ranging from 1.8 μm to 2.2 μm.

[0170] Clause 10. The method according to any of the preceding clauses, wherein removing a portion of the resist selectively forms a plurality of channels in the resist, the plurality of channels including a second channel for forming a second hollow wall.

[0171] The second channel includes a first surface and a second surface; and

[0172] The second channel includes a protrusion located at the corner between the first and second surfaces, the protrusion being configured to reduce deformation of the corresponding corner of the second hollow wall.

[0173] Clause 11. The method according to Clause 10, wherein the plurality of channels comprises: a first channel and two second channels, the first channel being a channel as defined in any one of claims 1 to 9, the two second channels being two second channels arranged on either side of the first channel.

[0174] Clause 12. A method for manufacturing a hollow wall for controlling the directional deposition of a material, the method comprising:

[0175] A layer of resist is formed on the substrate;

[0176] Selectively remove a portion of the resist to form channels within the resist;

[0177] Depositing an amorphous dielectric material layer in the channel; and

[0178] Remove the resist to form a hollow wall;

[0179] The channel includes a first surface and a second surface; and

[0180] The channel includes a protrusion located at the corner between the first and second surfaces, the protrusion being configured to prevent deformation of the corresponding corner of the hollow wall.

[0181] Clause 13. The method according to Clause 12, wherein the protrusion has a length in the range of 50 nm to 150 nm.

[0182] Clause 14. The method according to Clause 12 or Clause 13, wherein the protrusion forms an angle with respect to the first surface and the second surface in the range of 20° to 45°.

[0183] Clause 15. The method according to any one of Clauses 12 to 14, wherein the first surface and the second surface are serrated to prevent the corresponding first and second surfaces of the hollow wall from bending.

[0184] Clause 16. The method described in any one of Clauses 12 to 15, wherein the channel has a generally triangular shape.

[0185] Clause 17. A method of manufacturing a device, the method comprising:

[0186] Hollow walls are manufactured using the method according to any of the preceding claims; and

[0187] Material is selectively deposited over a substrate using a beam;

[0188] The beam is directed toward the substrate in a selected direction so that the hollow walls prevent material from depositing in the shadowed areas created by the hollow walls.

[0189] Clause 18. The method described in Clause 17 further includes removing the hollow wall after deposition.

[0190] Clause 19. The method according to Clause 18 or Clause 19, wherein the substrate comprises a semiconductor, and wherein the material comprises a superconducting material.

[0191] Clause 20. The method according to any one of Clauses 17 to 19 further comprises: forming nanowires on a substrate prior to deposition; and

[0192] The deposition includes selectively depositing material on at least a portion of the nanowire.

[0193] Once the disclosure herein is given, other variations or use cases of the disclosed technology may become apparent to those skilled in the art. The scope of this disclosure is not limited to the described embodiments, but only to the appended claims.

Claims

1. A method for manufacturing a hollow wall for controlling the directional deposition of a material, the method comprising: A layer of resist is formed on the substrate; Selectively remove a portion of the resist to form channels in the resist; An amorphous dielectric material layer is formed in the channel; as well as Remove the resist to form the hollow wall; The channel has a generally rectangular shape, the generally rectangular shape including a front surface, a rear surface opposite to the front surface, and a pair of side surfaces, the front surface being configured to prevent the corresponding front surface of the hollow wall from bending, and the generally rectangular shape including a chamfered corner between the front surface and one of the side surfaces in the pair of side surfaces, the chamfered corner having an interior angle with the corresponding side surface.

2. The method of claim 1, wherein the chamfered corner has a chamfer length selected to prevent bending of the front surface of the hollow wall.

3. The method according to claim 2, wherein the interior angle is in the range of 96° to 104°.

4. The method according to claim 2, wherein the chamfer length is in the range of 400 nm to 800 nm and / or wherein the side surfaces are spaced apart from each other by a distance in the range of 1.5 μm to 2.5 μm.

5. The method according to any one of claims 1 to 4, wherein the generally rectangular shape further includes a corresponding chamfered corner between each side surface and the rear surface in the pair of side surfaces.

6. The method of claim 1, wherein the front surface has an outward bend selected to prevent the front surface of the hollow wall from bending.

7. The method of claim 6, wherein the channel comprises a pair of opposing side surfaces at respective ends of the front surface; The outward curvature is such that the interior angle between the midpoint of the front surface and one of the side surfaces in the pair of opposite side surfaces is in the range of 96° to 104°.

8. The method of claim 7, wherein the opposite side surfaces are spaced apart by a distance ranging from 1.8 μm to 2.2 μm.

9. The method according to any one of claims 1 to 4, wherein the portion of the resist removed forms a plurality of channels in the resist, the plurality of channels including a second channel for forming a second hollow wall. The second channel includes a first surface and a second surface; The second channel includes a protrusion disposed at the corner between the first surface and the second surface, the protrusion being configured to reduce deformation at the corresponding corner of the second hollow wall.

10. The method of claim 9, wherein the plurality of channels comprises: A first channel and two second channels, wherein the first channel is a channel as defined in any one of claims 1 to 4, and the two second channels are arranged on either side of the first channel.

11. A method for manufacturing a hollow wall for controlling the directional deposition of a material, the method comprising: A layer of resist is formed on the substrate; Selectively remove a portion of the resist to form channels in the resist; An amorphous dielectric material layer is deposited in the channel; as well as Remove the resist to form the hollow wall; The channel includes a first surface and a second surface; as well as The channel includes a protrusion disposed at the corner between the first surface and the second surface, the protrusion being configured to prevent deformation of the corresponding corner of the hollow wall.

12. The method of claim 11, wherein the protrusion has a length in the range of 50 nm to 150 nm; and / or wherein the protrusion forms an angle in the range of 20° to 45° with respect to the first surface and the second surface.

13. The method according to claim 11 or 12, wherein the first surface and the second surface are serrated to prevent the corresponding first and second surfaces of the hollow wall from bending.

14. The method according to any one of claims 11 to 12, wherein the channel has a generally triangular shape.

15. A method of manufacturing a device, the method comprising: Hollow walls are manufactured using the method according to any one of claims 1 to 14; as well as Material is selectively deposited over a substrate using a beam; The beam is directed toward the substrate in a selected direction so that the hollow wall prevents the material from being deposited in the shadowed area created by the hollow wall.

16. The method of claim 15, further comprising removing the hollow wall after the deposition.

17. The method of claim 15, wherein the substrate comprises a semiconductor, and wherein the material comprises a superconducting material.

18. The method according to any one of claims 15 to 17, further comprising: Nanowires are formed on the substrate prior to the deposition; as well as The deposition includes selectively depositing the material on at least a portion of the nanowires.

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