TWI607861B - Exposure method, exposure equipment and 3-d structure - Google Patents

Description

Exposure method, exposure apparatus and three-dimensional structure

The present disclosure relates to a 3D printing technique, and in particular to an exposure method, an exposure apparatus, and a three-dimensional structure formed thereby.

Due to its low cost and simple process, 3D printing technology has attracted wide attention in design and manufacturing in recent years. However, limited by the technical capabilities of the fabrication equipment, the critical dimensions of the fabricated 3D structures are on the order of tens of microns, which is not conducive to the production of miniature and fine products.

For example, in a 3D structure fabricated by an inkjet printing process, the critical dimension of the final structure is limited by the size of the ink droplets. Furthermore, in the 3D structure fabricated by the Selective Laser Sintering or Selective Laser Melting process, the critical dimension of the final structure is limited by the beam size of the source. Since the critical dimension cannot be further reduced, the application of 3D printing to MEMS and printed electronics is limited. Therefore, there is still a need to improve the 3D printing technology to have a smaller critical dimension.

An embodiment of the present disclosure provides an exposure method comprising: coating a photocurable material on a substrate; providing a first light source by using an optical fiber for exposure, curing at least a portion of the photocurable material to form a first photocurable material And wherein the optical fiber has a light output end, and a tapered portion that gradually narrows toward the light output end; and removes the photocurable material that is not exposed by the first light source, leaving the first photocurable material.

Another embodiment of the present disclosure provides an exposure apparatus including: a carrier platform, wherein the carrier platform is configured to place a photocurable material; and a light source module, wherein the light source module includes an optical fiber, wherein the optical fiber has a light output end, and the light is directed toward the light The tapered end of the output is tapered, and the optical fiber provides a light source to perform an exposure step on the photocurable material; and a control module that controls the movement of the optical fiber.

Yet another embodiment of the present disclosure provides a three-dimensional structure including: a substrate; and a photocurable structure formed on the substrate, wherein the photocurable structure has a height of 10 to 1000 μm in a direction perpendicular to an upper surface of the substrate, and is cured The structure has a width and a length in a direction parallel to the upper surface of the substrate, wherein at least one of the width and the length is 1-100 nm.

100‧‧‧Exposure equipment

110‧‧‧Loading platform

120‧‧‧Light source module

130‧‧‧Control Module

202‧‧‧Substrate

204, 204-1, 204-2‧‧‧Photocurable materials

204a, 204a-1, 204a-2, 204b-1‧‧‧ light curing materials

206‧‧‧Photomask

210‧‧‧ fiber

210-A‧‧‧Light output

210-B‧‧‧Cone

212‧‧‧Light source generator

220, 510‧‧‧ light source

250, 260‧‧‧ three-dimensional structure

260a‧‧‧Part 1

260b‧‧‧ Part II

610‧‧‧etching tank

620‧‧‧etching solution

630‧‧‧ Controller

D‧‧‧Distance

L‧‧‧ length

R‧‧‧ area

W‧‧‧Width

△x, △y, △z‧‧‧ critical dimensions

1 is a schematic cross-sectional view of an exposure apparatus according to some embodiments of the present disclosure.

2A-2B are schematic cross-sectional views showing processes of an exposure method according to some embodiments of the present disclosure.

Figure 3 is an enlarged cross-sectional view of the region R of Figure 2A.

4A-4E are schematic cross-sectional views showing a process of an exposure method according to some embodiments of the present disclosure.

5A-5E are schematic cross-sectional views showing processes of an exposure method according to other embodiments of the present disclosure.

6A-6B illustrate forming a tapered portion of some embodiments of the present disclosure Schematic diagram of the process profile of the optical fiber.

The above and other objects, features and advantages of the present invention will become more <RTIgt; In order to simplify the drawings and highlight the technical features, the components may not be drawn to scale. The same element symbols may be used in the various embodiments to simplify the description, but this does not necessarily mean that there is a certain degree of association between the embodiments.

FIG. 1 is a cross-sectional view of an exposure apparatus 100 in accordance with some embodiments of the present disclosure. Referring to FIG. 1 , the exposure apparatus 100 can include a carrying platform 110 , a light source module 120 , and a control module 130 . The carrier platform 110 is used to place the substrate 202. In some embodiments, the substrate 202 can be first fixed on the carrying platform 110 by using a vacuum system (not shown) of the carrying platform 110, and then the material to be exposed, for example, the photocurable material 204, is applied to the substrate 202. on. In some embodiments, the carrier platform 110 can be configured to control the movement of the substrate 202 and the photocurable material 204 in the Z-axis direction. In other words, the distance between the photocurable material 204 and the light source module 120 can be controlled by the carrier platform 110.

The light source module 120 includes a light source generator 212 and an optical fiber 210. The light source module 120 can be configured to provide an exposure source that cures the photocurable material 204. The exposure source can include ultraviolet light. The wavelength λ of the exposure light source may be 100-450 nm. In some embodiments, the source wavelength λ can be from 100 to 400 nm. In other embodiments, the source wavelength λ can be between 200 and 400 nm. The exposure source can be a line source or a laser.

With continued reference to FIG. 1, the optical fiber 210 has a light output end 210-A and a tapered portion 210-B that tapers toward the light output end 210-A. In the exposure step The optical fiber 210 is configured to conduct the exposure light source emitted by the light source generator 212 to the photocurable material 204. Compared with the optical fiber without the tapered portion, since the optical fiber 210 has the tapered portion 210-B, the light output area of the light output end 210-A can be greatly reduced, and the critical dimension of the three-dimensional structure can be greatly reduced. Discussed in detail below.

The control module 130 is configured to control the movement of the optical fiber 210 in the X-axis, Y-axis, and Z-axis directions, thereby locally exposing the photocurable material 204. Wherein, by controlling the movement of the optical fiber 210 in the Z-axis, the control module 130 can adjust the exposed line width and help to reduce the critical dimension of the three-dimensional structure. In some embodiments, the control module 130 can use, for example, a control module suitable for an atomic force microscope, which can generally include a piezoelectric ceramic scanner, a cantilever beam, an offset detector, a scanner, a feedback circuit, and a computer control. system. Here, for the sake of simplicity, the cantilever beam is only schematically illustrated.

2A-2B are schematic cross-sectional views showing processes of an exposure method according to some embodiments of the present disclosure. Referring to FIG. 2A, first, a layer of photocurable material 204 is coated on the substrate 202. Substrate 202 can comprise a semiconductor substrate, glass, polymeric material, ceramic, metal, or a combination thereof. The photocurable material 204 is a polymer material having fluidity and can be uniformly coated on the surface of the substrate 202 to form a film. When the photocurable material 204 is irradiated (exposed) by light of a specific wavelength, the polymer is cured by a crosslinking reaction. The photocurable material 204 has a photocurable functional group, for example, an alkenyl group, a carboxyl group, an unsaturated polyester group, an acryl group, an epoxy group. Or other suitable functional groups. The photocurable material 204 can use any suitable photocurable material. In some embodiments, the photocurable material 204 Negative photoresist materials may be included, for example, phenolic resins, polyisoprene rubber, or other negative photoresist materials. In some embodiments, the photocurable material 204 can comprise an epoxy, an acrylic, or other suitable photocurable polymer.

With continued reference to FIG. 2A, light source 220 is then utilized to conduct light source 220 to the surface of photocurable material 204, thereby exposing portions of photocurable material 204 to form photocurable material 204a. Referring to FIG. 2B, next, after the photocurable material 204a is formed, the photocurable material 204 that is not cured by exposure of the light source 220 is removed. It will be understood herein that the size of the photocurable material 204a is dependent on the light output area of the light output end 210-A. The smaller the light output area, the smaller the size of the cured material 204a. In the present disclosure, by forming the tapered portion 210-B at one end of the optical fiber 210, the light output area of the light output end 210-A can be greatly reduced. Therefore, the critical dimension of the three-dimensional structure can be effectively reduced.

6A-6B are schematic cross-sectional views showing a process for forming an optical fiber 210 having a tapered portion according to some embodiments. The dotted line in the figure is an enlarged schematic view of the tip end of the optical fiber 210 in the etching solution 620. Referring to FIG. 6A, first, an etching solution 620 is placed in the etching bath 610, and a part of the optical fiber 210 is immersed in the etching solution 620. Next, as shown in FIG. 6B, the optical fiber 210 is slowly and gradually extracted from the etching solution 620 by the controller 630. The longer the portion closer to the end point is immersed in the etching solution 620, the more the fiber material is removed by etching. In this way, the optical fiber 210 having the tapered portion 210-B can be formed.

The optical fiber 210 can be selected from conventional optical fiber materials. In some embodiments, the optical fiber 210 can comprise quartz glass. The etching solution 620 can be an acidic solution or a base. Sexual solution or other suitable etching solution. A suitable etching solution 620 can be selected depending on the material of the optical fiber 210. For example, in embodiments where the optical fiber 210 is quartz glass, a hydrofluoric acid (HF) solution may be selected as the etching solution 620.

The function of controller 630 is to control the rate at which fiber 210 is extracted from etching solution 620. By adjusting the extraction speed of the optical fiber 210, the profile of the tapered portion 210-B and the light output area of the light output terminal 210-A can be adjusted. For example, the slower the extraction speed, the smaller the light output area of the light output terminal 210-A. In some embodiments, controller 630 can include a stepper motor.

As shown in FIG. 6B, by immersing in the etching solution 620, the light output area of the light output end 210-A of the optical fiber 210 can be greatly reduced. In some embodiments, the light output end 210-A has a light output area of 10-10 ⁶ nm ² . In some embodiments, the light output end 210-A has a light output area of 10-10 ⁵ nm ² . In some embodiments, the light output end 210-A has a light output area of 10-10 ⁴ nm ² . Since the light output area of the light output terminal 210-A is lowered, the resolution of the exposure process is improved, and the critical dimension of the three-dimensional structure can also be reduced.

In the present embodiment, the etching is performed by an isotropic etching method, and the optical fiber 210 used is cylindrical, so that the obtained light output terminal 210-A has a substantially circular cut surface. However, the disclosure is not limited thereto. The light output end 210-A can also have other shaped cut surfaces, such as rectangular, elliptical or irregular polygons. In order to change the shape of the cut surface of the light output end 210-A, the above etching step may be performed using the optical fiber 210 having other shapes (for example, rectangular) cut surfaces, or the optical fiber 210 may be etched by other etching methods (for example, dry etching). Further, the tapered portion 210-B may be formed by a mechanical grinding or molding method.

The inventor of the present invention found that the profile of the tapered portion 210-B, light can be The choice of curing material and the distance between the fiber and the photocurable material may affect the exposure process. These parameters are discussed in detail below.

Figure 3 is an enlarged cross-sectional view of the region R of Figure 2A. Referring to FIG. 3, the cross-sectional profile of the tapered portion 210-B has a length L and a width W. The ratio L/W of the length L to the width W can be controlled within a specific range. In some embodiments, the ratio L/W of length L to width W is 5-20. If the ratio of L/W is too small, the exposure light source will be largely lost in the tapered portion, and it is difficult to effectively cure the photocurable material. In addition, when the ratio of L/W is too small, it is difficult to control the soaking time because the length L soaked in the etching solution is too short. Once the immersion time is too short, the amount of fiber removed by the etch is too small to effectively reduce the light output area of the light output end 210-A. On the other hand, if the immersion time is too long, the amount of the optical fiber to be removed by etching is too large, so that the width of the tapered portion 210-B cannot be gradually narrowed, but is sharply narrowed. As a result, the fiber will be broken. However, if the ratio of L/W is too large, the length L of the tapered portion 210-B is too long, and the control module will have difficulty in accurately controlling the amount of movement of the optical fiber, and may cause optical fiber during the process of moving the optical fiber. Bend or flex.

Still referring to Figure 3, the length L of the tapered portion 210-B can be controlled within a particular range depending on the wavelength of the exposure source used. In some embodiments, the wavelength of the exposure source is λ, and the ratio L/λ of the length L to the wavelength λ is, for example, greater than 10. It is worth noting that when the profile of the optical fiber 210 changes too much, the ability of the optical fiber 210 to condense the exposure light source is greatly reduced. Therefore, by controlling the ratio L/λ of the length L of the tapered portion 210-B to the wavelength λ to be greater than 10, it is ensured that the contour change of the optical fiber 210 does not affect the convergence of the exposure light source, thereby improving the stability of the exposure process of the present disclosure. .

What is specifically stated here is that when selecting a photocurable material, it is required What is to be considered is the matching of the photocurable material to the exposure source and the ratio of the refractive index of the photocurable material to the refractive index of the fiber. When an energy mismatched exposure light source is used, it may result in incomplete curing of the photocurable material or a too low curing reaction rate. As a result, energy consumption and production costs will be increased and the yield of the product will be reduced. Therefore, a suitable photocurable material can be selected according to the wavelength of the exposure light source, and the desired exposure light source can be used according to the photocurable material. In some embodiments, the photocurable material may be a polymer material having a functional group such as an unsaturated polyester group, an acrylonitrile group or an epoxy group, and the exposure light source used is UV light having a wavelength of 100 to 400 nm. In addition, in order for light to be output from the light output end into the photocurable material, the refractive index of the photocurable material should be as close as possible to the refractive index of the fiber. If the refractive index of the photocurable material is too low, the light may cause total reflection at the interface between the optical fiber and the photocurable material, so that the light cannot enter the photocurable material. In some embodiments, the optical fiber has a refractive index n1, the photocurable material has a refractive index n2, and n1/n2 is 0.9-1.1. In other embodiments, the refractive index n1 of the optical fiber can be substantially equal to the refractive index n2 of the photocurable material.

Still referring to FIG. 3, during the exposure step, the optical fiber 210 is separated from the photocurable material 204 by a distance D. In the present disclosure, this distance D is also referred to as the shortest distance between the fiber and the photocurable material. The distance D can be controlled within a specific range. In some embodiments, the distance D between the fiber and the photocurable material is from 0.1 to 100 nm. In other embodiments, the distance D between the fiber and the photocurable material is from 0.1 to 1 nm. If the distance D is too small to directly contact the optically curable material, the uncured photocurable material may adhere to the surface of the fiber and solidify, resulting in shortened fiber life and scratching the photocurable material. Surface, which in turn reduces product yield and increases production costs. Conversely, if the distance If D is too large, the optical output efficiency of the optical fiber is lowered. As a result, the exposure time will be prolonged, which will reduce the production efficiency. Furthermore, if the distance D is too large, the effect of focusing light output from the optical fiber is deteriorated. Therefore, the critical dimension of the obtained three-dimensional structure also increases, which is disadvantageous for miniaturization of the critical dimension.

Due to the different surface roughness of the photocurable material or the underlying substrate, the distance D between the optical fiber and the photocurable material may be changed to affect the uniformity of the exposure process. Therefore, in some embodiments of the present disclosure, the Z-axis of the optical fiber can be finely adjusted through a control module (not shown) to maintain a fixed distance between the optical fiber and the photocurable material to improve the uniformity of the exposure process in different regions. Sex. As described above, the control module is, for example, a control module having a vertical fine adjustment capability such as an atomic force microscope.

The disclosure also provides an exposure method. 4A to 4E are schematic cross-sectional views showing a process of an exposure method according to some embodiments of the present disclosure. Referring to FIG. 4A, first, a photocurable material 204-1 is coated on the substrate 202. The materials of the substrate 202 and the photocurable material 204-1 are as described above and will not be described in detail herein. The photocurable material 204 can be applied by a suitable method, for example, spin coating, immersion coating, spray coating, printing, and the like. Next, as shown in FIG. 4B, the light source 220 is conducted to the surface of the photocurable material 204-1 by using the optical fiber 210, thereby exposing the surface of at least a portion of the photocurable material 204-1 to form the photocurable material 204a-1. .

Referring to FIG. 4C, the photocurable material 204-2 is coated on the photocurable material 204-1. Next, referring to FIG. 4D, the light source 220 is conducted to the surface of the photocurable material 204-2 by using the optical fiber 210, thereby curing at least a portion of the light. The surface of the material 204-2 is exposed to form a photocurable material 204a-2. The material and coating method selected for the photocurable material 204-2 can be similar to the photocurable material 204-1, and will not be described in detail herein. In some embodiments, the photocurable material 204-2 is the same as the photocurable material 204-1. In other embodiments, the photocurable material 204-2 can also be different than the photocurable material 204-1, so the optical fiber 210 and the exposure light source 220 can be replaced as needed.

In some embodiments, the steps of Figures 4A-4B can be repeated multiple times to obtain the desired three-dimensional structure. In other embodiments, when the photocurable material 204-2 is different from the photocurable material 204-1, the steps of FIGS. 4A-4B and 4C-4D may be repeated multiple times depending on the desired three-dimensional structure, The photocurable materials 204a-1 and 204a-2 in the final structure are each provided to have a desired thickness. This thickness is measured along a direction perpendicular to the upper surface of the substrate (i.e., the Z-axis direction), and thus, in the present disclosure, this thickness may also be referred to as a height. The height of the photocurable materials 204a-1 and 204a-2 can reach the order of micrometers or more. In some embodiments, the height of the photocurable materials 204a-1 and 204a-2 may range from 10 to 1000 [mu]m.

It should be noted that the embodiments set forth in the disclosure are for illustrative purposes only and are not intended to be limiting. It should be understood by those skilled in the art that depending on the desired three-dimensional structure, the photocurable material may include three or more kinds, and the number of exposure steps of each photocurable material may be determined according to the required height.

Referring to FIG. 4E, after all the exposure steps are completed, the photocurable materials 204-1 and 204-2 not exposed by the light source 220 are removed, and the photocurable materials 204a-1 and 204a-2 are left to form a three-dimensional structure 250. . The photocurable materials 204-1 and 204-2 can be removed using a suitable method, for example, plasma ashing or cleaning with a developer. In this embodiment, in order to shorten the time required for the process, the photocurable material The removal step of the material is carried out after all the exposure steps have been completed. However, the order and number of steps of removing the photocurable material can be adjusted as needed. For example, in some embodiments, the step of removing the photocurable material can be performed once after each exposure step is completed.

Referring to FIG. 4E, the dimension of the three-dimensional structure 250 in the X direction is Δx, the dimension in the Y direction is Δy, and the dimension in the Z direction is Δz. The minimum values that Δx, Δy, and Δz can achieve are defined as the critical dimensions of the three-dimensional structure 250 in the X, Y, and Z directions, respectively. It should be understood that the critical dimensions of the three-dimensional structure 250 in the X, Y, and Z directions are respectively determined by the minimum moving distance of the optical fiber 210 in the X, Y, and Z directions (ie, the control module is in the X, Y, and Z directions). Control accuracy on the basis). As described above, in some embodiments, when the control module of the atomic force microscope is used to control the movement of the optical fiber 210, the minimum moving distance of the optical fiber 210 in the X, Y, and Z directions can reach the nanometer level, and the three-dimensional structure can be greatly reduced. Critical dimension. In some embodiments, the critical dimensions Δx, Δy, and Δz of the three-dimensional structure 250 in the X, Y, and Z directions may each be 1-100 nm.

5A-5E are schematic cross-sectional views showing processes of an exposure method according to other embodiments of the present disclosure. In order to simplify the explanation, the portions in FIGS. 5A to 5E which are the same as those in FIGS. 4A to 4E are not described in detail. Referring to FIG. 5A, a photocurable material 204 is coated on the substrate 202. Next, referring to FIG. 5B, a mask 206 is provided as a mask, and a portion of the surface of the photocurable material 204 is exposed by the light source 510 to form a photocurable material 204b-1, as shown in FIG. 5C. After the photocurable material 204b-1 is formed, the photomask 206 is removed. Then, referring to FIG. 5D, after removing the reticle 206, the remaining portion of the photocurable material 204 (ie, previously masked by the reticle 206) is shielded by the optical fiber 210 and the light source 220 by the method described in the previous embodiment. Part or The portion which has not been cured by the light source 510 is exposed to form the photocurable material 204a-1.

Referring to FIG. 5E, the steps of FIGS. 5A-5D may be repeated multiple times to complete the three-dimensional structure 260. The three-dimensional structure 260 includes a first portion 260a and a second portion 260b. The first portion 260a is exposed and cured using the optical fiber 210 and the light source 220, and thus has a smaller critical dimension. The second portion 260b is cured by large-area exposure using the light source 510, so the critical dimension is much larger than the first portion 260a. In particular, in the present embodiment, the mask 206 and the light source 510 are first exposed to a large area, and then the optical fiber 210 and the light source 220 are exposed to portions that have not been cured by the light source 510. In other embodiments, a small area exposure may be performed by using the optical fiber 210 and the light source 220 as needed, and then the large area exposure is performed by the photomask 206 and the light source 510.

The embodiment illustrated in Figures 5A through 5E is a two-step exposure method that uses light sources of the same wavelength but different light output areas. The use of a light source with a small positive light source for a very small area of exposure and curing reaction can reduce the critical dimension of the three-dimensional structure. On the other hand, a large-area exposure and curing reaction is performed by using a light source having a large light output area, which can greatly reduce the time required for the process and improve the production efficiency. Therefore, the present embodiment can quickly and mass-produce a three-dimensional structure of high complexity and high precision.

In summary, the present disclosure provides an exposure apparatus. The exposure apparatus includes an optical fiber having a tapered portion, thereby greatly reducing the light output area and the critical dimension of the three-dimensional structure. Moreover, the exposure device controls the movement of the optical fiber in the X, Y, and Z directions, and simultaneously reduces the critical dimension of the three-dimensional structure in the three-dimensional direction, and also improves the uniformity of the exposure process in different regions. In addition, the present disclosure also provides an exposure method. In some embodiments, this exposure method has The tapered portion of the optical fiber exposes and cures the photocurable material, which greatly reduces the critical dimension of the three-dimensional structure. In other embodiments, the present disclosure provides a two-step exposure method. The two-step exposure method can perform high-complexity and high-precision three-dimensional structures quickly and in large quantities by exposing and curing the photocurable material using light sources having the same wavelength but different light output areas.

While the invention has been described above in terms of several preferred embodiments, it is not intended to limit the scope of the present invention, and any one of ordinary skill in the art can make any changes without departing from the spirit and scope of the invention. The scope of the present invention is defined by the scope of the appended claims.

100‧‧‧Exposure equipment

110‧‧‧Loading platform

120‧‧‧Light source module

130‧‧‧Control Module

202‧‧‧Substrate

204‧‧‧Photocurable materials

210‧‧‧ fiber

210-A‧‧‧Light output

210-B‧‧‧Cone

212‧‧‧Light source generator

Claims (13)

An exposure method comprising: coating a photocurable material on a substrate; using a fiber to provide a first light source for exposure, curing at least a portion of the photocurable material to form a first photocurable material, wherein The optical fiber has a light output end and a tapered portion that tapers toward the light output end; and the photocurable material that is not exposed by the first light source is removed, leaving the first photocurable material. The exposure method of claim 1, wherein the light output end has a light output area of 10 - 10 ⁶ nm ² . The exposure method of claim 1, wherein the tapered portion of the optical fiber has a length L and a width W in a cross-sectional view, wherein a ratio L/W of the length L to the width W is 5- 20. The exposure method of claim 3, wherein the light source has a wavelength λ, and a ratio L/λ of the length L to the wavelength λ is greater than 10. The exposure method of claim 1, wherein the optical fiber has a first refractive index n1, the photocurable material has a second refractive index n2, and the first refractive index and the second refractive index The ratio n1/n2 is 0.9-1.1. The exposure method of claim 1, wherein the shortest distance between the optical fiber and the photocurable material is from 0.1 to 100 nm when the photocurable material is exposed. The exposure method of claim 1, further comprising repeating the coating, exposing and removing steps at least once to form a three-dimensional structure. The exposure method of claim 1, further comprising: forming a patterned mask layer on the photocurable material before the exposing by using the first light source; Exposing the photocurable material covered by the patterned mask layer to form a second photocurable material; and removing the patterned photomask layer, wherein the step of exposing with the first light source is directed to the second light The photocurable material other than the cured material is implemented. An exposure apparatus includes: a carrier platform, wherein the carrier platform is configured to place a photocurable material; and a light source module, wherein the light source module comprises an optical fiber, wherein the optical fiber has a light output end, and the light is facing The output end is tapered by a tapered portion, and the optical fiber provides a light source to perform an exposure step on the photocurable material; and a control module controls the movement of the optical fiber. The exposure apparatus of claim 9, wherein the light output end has a light output area of 10 - 10 ⁶ nm ² . The exposure apparatus of claim 9, wherein the tapered portion of the optical fiber has a length L and a width W in a cross-sectional view, wherein a ratio L/W of the length L to the width W is 5- 20. The exposure apparatus of claim 10, wherein the light source has a wavelength λ, and a ratio L/λ of the length L to the wavelength λ is greater than 10. The exposure apparatus of claim 9, wherein the control module moves the optical fiber in the X direction by a minimum distance of Δx, and the minimum distance of the optical movement in the Y direction is Δy, and moves in the Z direction. The minimum distance is Δz, where At least one of Δx, Δy, and Δz is 1-100 nm.