Patent Application
20240153883
This application is based on and claims priority under 35 U.S.C. § 119 to Korean Patent Application No. 10-2022-0147373, filed on Nov. 7, 2022, in the Korean Intellectual Property Office, the disclosure of which is incorporated by reference herein in its entirety.
Example embodiments of the present disclosure relate to a device including an overlay target structure.
The degree of integration of various integrated circuit devices including a memory, a driving integrated circuit (IC), a logic device, an image sensor, and the like is increasing, and thus, the size of electronic elements provided therein is decreasing. In addition, optical elements may be made flat on a wafer substrate in a nanostructure.
These electronic and optical elements formed on different substrates may be packaged in a single package by using an alignment mark provided on each substrate. The alignment marks include patterns that transmit and reflect light, and the degree of alignment may be confirmed by detecting transmission, reflection, and scattering patterns according to an overlay form of facing alignment marks.
In order to improve the alignment precision, the shape dimensions of the patterns provided in the alignment marks are reduced, however it is difficult to implement a sub-micron level, for example, 100 nm level of measurement precision, due to an optical resolution limit.
One or more example embodiments provide an alignment key capable of increasing the alignment precision when manufacturing an electronic device and a device including the same.
Additional aspects will be set forth in part in the description which follows and, in part, will be apparent from the description, or may be learned by practice of the example embodiments of the disclosure.
According to an aspect of an example embodiment, there is provided a device including a substrate, and an overlay target structure provided on the substrate, wherein the overlay target structure includes a first alignment key having a first pattern that includes a plurality of first line masks provided at a first pitch in a second direction, each first line mask of the plurality of first line masks having a first width in the second direction and a first length in a first direction perpendicular to the second direction, a second alignment key spaced apart from the first alignment key in a third direction perpendicular to the first direction and the second direction to face the first alignment key, and having a second pattern that includes a plurality of second line masks provided at a second pitch in the second direction, each second line mask of the plurality of second line masks having a second width in the second direction and a second length in the first direction, and a nanostructure layer including a plurality of nanostructures between the first alignment key and the second alignment key, each nanostructure of the plurality of nanostructures having a width that is less than or equal to the first width and the second width and being provided at a pitch that is less than the first pitch and the second pitch.
The plurality of nanostructures may include a metal material or a dielectric material.
Each nanostructure of the plurality of nanostructures may have a cylindrical shape or polygonal pillar shape, and wherein a cross-section diameter or one side of each nanostructure of the plurality of nanostructures may be less than or equal to the first width and the second width.
The plurality of nanostructures may be provided in two or more layers in the third direction.
An interval between adjacent layers among the two or more layers may be less than or equal to 100 nm.
Each first line mask of the plurality of first line masks and each second line mask of the plurality of second line masks includes a metal material.
The first pattern may include a plurality of first groups, each first group of the plurality of first groups including the plurality of first line masks, and the plurality of first groups may be provided in the first direction, and adjacent groups of the plurality of first groups are offset at a predetermined interval in the second direction with respect to each other.
The plurality of first groups may be provided in the first direction and gradually offset in the second direction.
The predetermined interval may be less than or equal to ½ of the first width.
The predetermined interval may be less than or equal to 100 nm.
A size of each first group of the plurality of first groups in the first direction may be greater than or equal to 1 μm.
The first alignment key may further include a third pattern on a same layer as the first pattern, the third pattern including a plurality of third line masks provided at a third pitch in the first direction, each third line mask of the plurality of third line masks having a third length in the second direction and a third width in the first direction, and the second alignment key may further include a fourth pattern on a same layer as the second pattern, the fourth pattern including a plurality of fourth line masks provided at a fourth pitch in the first direction, each fourth line mask of the plurality of fourth line masks having a fourth length in the second direction and a fourth width in the first direction.
The first pattern may include a plurality of first groups, each first group of the plurality of first groups including the plurality of first line masks, the plurality of first groups may be provided in the first direction, and adjacent groups of the plurality of first groups may be offset at a predetermined interval in the second direction with respect to each other.
The third pattern may include a plurality of third groups, each third group of the plurality of third groups including the plurality of third line masks, and the plurality of third groups may be provided in the second direction, and adjacent groups of the plurality of third groups may be offset at a predetermined interval in the first direction with respect to each other.
The plurality of first groups included in the first pattern may form a first set, and the plurality of third groups included in the third pattern key may form a third set, the first alignment key may further include a second set including a plurality of second groups having a configuration same as the first set and a fourth set including a plurality of fourth groups having a configuration same as the third set, and a trajectory in which the plurality of first groups included in the first set, the plurality of second groups included in the second set, the plurality of third groups included in the third set, and the plurality of fourth groups included in the fourth set are provided is rectangular.
The first alignment key may further include a mask pattern in a central portion of a rectangular trajectory formed by the first set, the second set, the third set, and the fourth set.
According to another aspect of an example embodiment, there is provided a device including a substrate, a first alignment key having a first pattern that includes a plurality of first line masks provided at a first pitch in a second direction, each first line mask of the plurality of first line masks having a first width in the second direction and a first length in a first direction perpendicular to the second direction, and a nanostructure layer including a plurality of nanostructures provided on the first alignment key, each nanostructure of the plurality of nanostructures having a width that is less than the first width and provided at a pitch less than the first pitch.
The first alignment key may further include a third pattern on a same layer as the first pattern, and includes a plurality of third line masks provided at a third pitch in the first direction, each third line mask of the plurality of third line masks having a third length in the second direction and a third width in the first direction.
The first pattern may include a plurality of first groups, each first group of the plurality of first groups including the plurality of first line masks, the plurality of first groups may be provided in the first direction, and adjacent groups of the plurality of first groups may be offset at a predetermined interval in the second direction with respect to each other.
The third pattern may include a plurality of third groups, each third group of the plurality of third groups having the plurality of third line masks, the plurality of third groups may be provided in the second direction, and adjacent groups of the plurality of third groups may be offset at a predetermined interval in the first direction with respect to each other.
The above and other aspects, features, and advantages of certain example embodiments of the disclosure will be more apparent from the following description taken in conjunction with the accompanying drawings, in which:
Reference will now be made in detail to embodiments, examples of which are illustrated in the accompanying drawings, wherein like reference numerals refer to like elements throughout. In this regard, the example embodiments may have different forms and should not be construed as being limited to the descriptions set forth herein. Accordingly, the embodiments are merely described below, by referring to the figures, to explain aspects. As used herein, the term “and/or” includes any and all combinations of one or more of the associated listed items. Expressions such as “at least one of,” when preceding a list of elements, modify the entire list of elements and do not modify the individual elements of the list. For example, the expression, “at least one of a, b, and c,” should be understood as including only a, only b, only c, both a and b, both a and c, both b and c, or all of a, b, and c.
Hereinafter, example embodiments will be described in detail with reference to the accompanying drawings. The embodiments described below are merely exemplary, and various modifications are possible from these embodiments. In the following drawings, the same reference numerals refer to the same components, and the size of each component in the drawings may be exaggerated for clarity and convenience of description.
Hereinafter, the term “upper portion” or “on” may also include “to be present above on a non-contact basis” as well as “to be on the top portion in directly contact with”.
Terms such as first and second may be used to describe various components, but are used only for the purpose of distinguishing one component from another component. These terms do not limit the difference in the materials or structures of the components.
Singular expressions include plural expressions unless they are explicitly meant differently in context. In addition, when a part “includes” a component, this means that it may include more other components, rather than excluding other components, unless otherwise stated.
Further, the terms “unit”, “module” or the like mean a unit that processes at least one function or operation, which may be implemented in hardware or software or implemented in a combination of hardware and software.
The use of the term “the” and similar indicative terms may correspond to both singular and plural.
Steps constituting the method may be performed in an appropriate order unless there is a clear statement that the steps should be performed in the order described. In addition, the use of all illustrative terms (e.g., etc.) is simply intended to detail technical ideas and, unless limited by the claims, the scope of rights is not limited due to the terms.
The device 1 includes a substrate SU and an overlay target structure OTS arranged on the substrate SU. The overlay target structure OTS includes a first alignment key 100, a second alignment key 200, and a nanostructure layer 500 arranged between the first alignment key 100 and the second alignment key 200.
The overlay target structure OTS is used to precisely couple two separately manufactured electronic devices. The overlay target structure OTS may be provided to be divided into two parts in the two substrate structures SS1 and SS2 to be coupled. The device 1 is an example of a structure in which, for example, a substrate structure SS1 having the first alignment key 100 and a part of the nanostructure layer 500, and a substrate structure SS2 having the second alignment key 200 and another part of the nanostructure layer 500 are combined. When combining two substrate structures SS1 and SS2, the degree of misalignment of the two substrate structures SS1 and SS2 may be measured from the transmission or reflection pattern after light passes through the overlay target structure OTS. Accordingly, it is possible to determine whether the misalignment of the two substrate structures SS1 and SS2 are good or bad. Thus, considering the measured results, the two substrate structures SS1 and SS2 may be aligned to their desired positions, or the conditions of bonding the two substrate structures SS1 and SS2 may be corrected. After the two substrate structures SS1 and SS2 are aligned to desired positions, they are directly bonded to each other. As illustrated by dotted circles, the two substrate structures SS1 and SS2 may be, for example, metal bonded or hybrid bonded. The shape in which the overlay target structure OTS is divided into two parts in the two substrate structures SS1 and SS2 is not limited to the shape shown in
The device 1 consisting of a combination of two substrate structures SS1 and SS2 includes a device layer DL made of, for example, an insulating pattern, a semiconductor pattern, a metal pattern, etc. The device 1 may be various semiconductor devices, for example, a memory device, a logic device, an image sensor, an integrated circuit device, or the like, and may be a flat nanostructure-based optical device formed on a wafer substrate, but embodiments are not limited thereto.
Referring to
Referring to
The first width w1, the first pitch p1, the second width w2, and the second pitch p2 may have a sub-wavelength, that is, may be less than a wavelength of a light used to measure alignment. The central wavelength of the wavelength band of light to be used will hereinafter be referred to as a reference wavelength. The reference wavelength may be, for example, approximately 1 μm. For example, w1 and w2 may be in a range of about 100 nm to about 300 nm, and p1 and p2 may be in a range of about 200 nm to about 600 nm, but these are only examples and embodiments are not limited thereto. The widths w1 and w2 may be the same or different from each other. The pitches p1 and p2 may also be the same or different from each other.
The line masks 10 of the first alignment key 100 and the line masks 20 of the second alignment key 200 may be made of metal materials. For example, the metal materials may include copper (Cu), tungsten (W), titanium (Ti), platinum (Pt), nickel (Ni), aluminum (Al), iridium (Ir), chromium (Cr), ruthenium (Ru), gold (Au), silver (Ag), molybdenum (Mo), titanium nitride (TiN), tantalum nitride (TaN), or tungsten nitride (WN). The material of the line masks 10 and 20 may be made of the same metal material as that of the metal pattern of the device layer DL located on the same layer as each of the line masks 10 and 20. The line masks 10 of the first alignment key 100 and the line masks 20 of the second alignment key 200 may be made of different metal materials. Each of the line masks 10 may include a plurality metal materials. Each of the line masks 10 may include a plurality of metal layers. The plurality of metal layers may be arranged in a direction perpendicular to the Z direction. Each of the line masks 20 may include a plurality metal materials. Each of the line masks 20 may include a plurality of metal layers. The plurality of metal layers may be arranged in a direction perpendicular to the Z direction.
When the metal material has a structure of not larger than the wavelength of incident light, it has a property of forming a surface plasmon, and in connection with this, the transmission and reflection patterns of light transmitted through the overlay target structure OTS vary according to the alignment shapes of the first alignment key 100 and the second alignment key 200. The measurement of the misalignment state of the line masks 10 and 20 with the illustrated sub-wavelength shape dimension requires approximately 10 nm to 200 nm of measurement precision, and it may be difficult to image the misalignment state by a general optical system due to a light diffraction limit.
The overlay target structure OTS according to an example embodiment includes a nanostructure layer 500 arranged between the first alignment key 100 and the second alignment key 200, and sub-wavelength imaging of a misaligned state between the first alignment key 100 and the second alignment key 200 may be possible by the nanostructure layer 500.
Referring to
Each of the plurality of nanostructures NS may include a plurality of metal materials. Each of the plurality of nanostructures NS may include a plurality of metal layers. The plurality of metal layers may be arranged along a radial direction. Each of the plurality of nanostructures NS may include a plurality of dielectric materials. Each of the plurality of nanostructures NS may include a plurality of dielectric layers. The plurality of dielectric layers may be arranged along a radial direction.
The nanostructure layer 500 may include a plurality of layers. The nanostructure layer 500 may include a plurality of layers arranged in a third direction (Z direction) perpendicular to the first direction (Y direction) and the second direction (X direction). For example, the nanostructures NS may be arranged between the first alignment key 100 and the second alignment key 200 to form different layers. Although illustrated as four layers in
The regions between the nanostructures NS in the nanostructure layer 500 may be filled with an insulating material. The insulating material may include, for example, SU-8, polymethyl methacrylate (PMMA), organosilicate glass (SiCOH), silicon carbon-nitride (SiCN), silicon oxide (SiO2), or SOG. When the nanostructures NS are formed of a dielectric material or a semiconductor material, the insulating material may have a refractive index less than those of the nanostructures NS. When the nanostructure layers 500 are formed of a plurality of layers, an interval between adjacent layers, that is, a thickness t of a region in which the nanostructures NS are not arranged in a horizontal direction (X direction or Y direction) in the nanostructure layers 500 may be set to be less than a predetermined reference value. For example, the thickness t may be about 1/10 or less of the reference wavelength. The thickness t may be approximately 100 nm or less. When the nanostructure layer 500 is formed of a plurality of layers, intervals between adjacent layers may be different from each other. For example, an interval between the first layer and the second layer and an interval between the second layer and the third layer may be different.
Although
The nanostructures NS may be made of the same metal material as that of a metal pattern of the device layer DL positioned on the same layer as each layer of the nanostructure layer 500. The nanostructures NS may be formed of a semiconductor material or a dielectric material such as a semiconductor pattern or a dielectric pattern of the device layer DL located on the same layer as each layer of the nanostructure layer 500. Accordingly, the nanostructures NS forming different layers may be formed of different materials. The insulating material around the nanostructures NS may be made of an insulating material used in the insulating pattern provided in the device layer DL located on each layer of the nanostructure layer 500.
The nanostructure layer 500 may transmit fine pattern information of light transmitted through the first alignment key 100 to the second alignment key 200 with little loss. This is because the plurality of fine nanostructures NS act similarly to a waveguide array which guides light in the vertical direction (Z-direction) and the effective refractive index of the nanostructure layer 500 in the horizontal direction (X direction and Y direction) is increased. When light transmitting through the first alignment key 100 travels inside the nanostructure layer 500, light lost in the horizontal direction (X direction or Y direction) may be reduced or minimized, and may reach the second alignment key 200 by proceeding in the vertical direction (Z direction).
In the computational simulations of
The overlay target structure OTS provided in the device 2 is different from the overlay target structure OTS illustrated in
The overlay target structure OTS1 includes a first alignment key 101, a nanostructure layer 500, and a second alignment key 201.
The first alignment key 101 includes a first pattern 110 and a third pattern 130. The first pattern 110 includes a plurality of line masks 10 that have a length direction of a first direction (Y direction) and a first width w1 in a second direction (X direction), and are arranged at a first pitch p1 in the second direction (X direction). The third pattern 130 includes a plurality of line masks 10 that have a length direction of a second direction (X direction) and a third width w3 in the first direction (Y direction), and are arranged at a third pitch p3 in the first direction (Y direction). The first width w1 and the third width w3 may be the same or different from each other. The first pitch p1 and the third pitch p3 may also be the same or different from each other.
The second alignment key 201 includes a second pattern 220 and a fourth pattern 240. The second pattern 220 includes a plurality of line masks 20 that have a length direction of a first direction (Y direction) and a second width w2 in the second direction (X direction), and are arranged at a second pitch p2 in the second direction (X direction). The fourth pattern 240 includes a plurality of line masks 20 having a length direction in the second direction (X direction) and a fourth width w4 in the first direction (Y direction), and are arranged at a fourth pitch p4 in the first direction (Y direction). The second width w2 and the fourth width w4 may be the same or different from each other. The second pitch p2 and the fourth pitch p4 may also be the same or different from each other. The first width w1 and the second width w2 may be the same or different from each other. The first pitch p1 and the second pitch p2 may be the same or different from each other. For example, the first pitch p1 and the second pitch p2 may be the same, and the first width w1 and the second width w2 may be different. The third pitch p3 and the fourth pitch p4 may be the same, and the third width w3 and the fourth width w4 may be different from each other.
The first pattern 110 and the second pattern 220 form a pair that may measure alignment errors in the second direction (X direction), and the third pattern 130 and the fourth pattern 240 form a pair that may measure alignment errors in the first direction (Y direction).
The overlay target structure OTS2 includes a first alignment key 102 and a second alignment key 202, and a nanostructure layer arranged between the first alignment key 102 and the second alignment key 202. Since the nanostructure layer is substantially the same as the nanostructure layer 500 described above, redundant illustration or description thereof will be omitted.
The first alignment key 102 includes a first pattern 112, and the first pattern 112 is divided into a plurality of groups 112a, 112b, 112c, 112d, and 112e. Although the first pattern 112 is illustrated to include five groups, this is only an example and embodiments are not limited thereto. The partitioned size, that is, the length in the first direction (Y direction) of each of the groups 112a to 112e, may be greater than or equal to a reference wavelength, for example, about 1 μm or more. Each of the groups 112a to 112e includes a plurality of line masks 10 that have a length direction of a first direction (Y direction) and a width w1 of a second direction (X direction), and are arranged at a first pitch p1 in the second direction (X direction). The groups 112a to 112e are arranged in the first direction (Y direction), and adjacent groups are arranged to be offset by an interval d in the second direction (X direction).
The groups 112a to 112e are arranged in the first direction (Y direction) in order that the offset interval in the second direction (X direction) gradually increases. For example, the offset intervals of the second group 112b to the fifth group 112e with respect to the first group 112a are d, 2d, 3d, and 4d, respectively.
The second alignment key 202 includes a second pattern 222. The second pattern 222 includes a plurality of line masks 20 that have a length direction of a first direction (Y direction) and a width w2 in the second direction (X direction), and are arranged at a second pitch p2 in the second direction (X direction). The second pattern 222 faces the first pattern 112 shown in
In the overlay target structure OTS2 as illustrated in
The overlay target structure OTS3 as illustrated in
The overlay target structure OTS3 includes a first alignment key 103 and a second alignment key 203. A nanostructure layer is arranged between the first alignment key 103 and the second alignment key 203, and since the nanostructure layer is substantially the same as the nanostructure layer 500 described above, redundant illustration or description thereof will be omitted.
The first alignment key 103 includes a first pattern 113 and a third pattern 133. The first pattern 113 includes a plurality of groups 113a, 113b, 113c, 113d, and 113e, and similar to the first pattern 112 shown in
The second alignment key 203 includes a second pattern 223 and a fourth pattern 243. Similar to the second pattern 222 shown in
The second patterns 223 are arranged to face the entire first pattern 113 to form a pair that measures a degree of misalignment in the second direction (X direction). The fourth pattern 243 is arranged to face the entire third pattern 133 to form a pair for measuring a degree of misalignment in the first direction (Y direction).
Referring to
Referring to
The size of the horizontal cross section (XY plane) of the overlay target structure OTS4 may be approximately 20 μm×20 μm to 300 μm×300 μm. For example, the number of groups of the first alignment keys 104 arranged in the first direction (Y direction) and the second direction (X direction) may be approximately 20 to 300. However, embodiments are not limited thereto.
In this way, the plurality of groups of the first alignment key 104 provided in the overlay target structure OTS4 may act as a two-dimensional scale to measure the degree of misalignment. For example, depending on the location of the group representing the brightest or darkest pattern, the degree of misalignment in the first direction (Y direction) and the second direction (X direction) may be easily measured.
Referring to
The first alignment key 105 includes a plurality of groups 115. The plurality of groups 115 are similar to the groups forming the first pattern 112 described in
For example, the first alignment key 105 corresponds to a form in which a plurality of first patterns 112 as described in
The second alignment key 205 includes a second pattern 225. Similar to the second pattern 222 shown in
This type of overlay target structure OTS5 may be used to measure misalignment in the X direction in more detail and accurately.
Referring to
The first alignment key 106 includes a plurality of groups 136, and each of the plurality of groups 136 has a length direction of the X direction and includes a plurality of line masks arranged in the Y direction. The second alignment key 206 includes a fourth pattern 246, and the fourth pattern 246 includes a plurality of line masks having a length direction of X direction and arranged in the Y direction.
The overlay target structure OTS6 according to the example embodiment corresponds to a shape in which the overlay target structure OTS5 of FIG. 12 rotates by 90 degrees, that is, may be used to measure misalignment in the Y direction in more detail and accurately.
Referring to
This type of overlay target structure OTS7 may be used to measure misalignment in the X direction and misalignment in the Y direction in more detail and accurately.
Referring to
Referring to
In
In
The overlay target structure described above has a structure capable of more precisely measuring alignment errors in the manufacture of stacking of various electronic and optical devices, and thus a device including the same may have improved precision.
It should be understood that embodiments described herein should be considered in a descriptive sense only and not for purposes of limitation. Descriptions of features or aspects within each example embodiment should typically be considered as available for other similar features or aspects in other embodiments. While example embodiments have been described with reference to the figures, it will be understood by those of ordinary skill in the art that various changes in form and details may be made therein without departing from the spirit and scope as defined by the following claims and their equivalents.
| Number | Date | Country | Kind |
|---|---|---|---|
| 10-2022-0147373 | Nov 2022 | KR | national |
