Electron beam direct writing device and electron beam direct writing method

Abstract

Provided in the present application are an electron beam direct writing device and an electron beam direct writing method. The electron beam direct writing device comprises: an electron source, which comprises a plurality of electron source units, wherein each electron source unit generates a corresponding electron beam; and a controller, which controls the electron source to generate at least one electron beam. The plurality of electron source units comprise at least one first electron source unit and at least one second electron source unit, an electron beam generated by each first electron source unit corresponds to an electron beam having a first beam spot, an electron beam generated by each second electron source unit corresponds to an electron beam having a second beam spot, and the area of the first beam spot is at least twice the area of the second beam spot. By means of the present application, the precision of electron beam direct writing is ensured, and the speed of electron beam direct writing can also be increased.

Description

Electron beam direct writing device and electron beam direct writing method Technical Field

[0001] The present application relates to the technical field of semiconductor integrated circuit manufacturing, and in particular to an electron beam direct writing device and an electron beam direct writing method. Background Art

[0002] The development of the semiconductor microfabrication industry is placing increasing demands on electron beam direct writing technology. These requirements include ensuring the accuracy of fine pattern imaging and significantly increasing direct writing speeds. To meet these industry demands, multi-electron beam direct writing technology is rapidly developing and playing an irreplaceable role in the direct writing of fine patterns in the integrated circuit manufacturing process.

[0003] Specifically, in semiconductor manufacturing, the imaging of high-tech node graphics (for example, the graphics of photomasks and the structural graphics of each layer of the device) requires not only finer and more accurate direct writing, but also high-speed direct writing when the amount of graphic data increases dramatically. From the perspective of accurate direct writing of fine graphics, the electron beam spot needs to be made smaller to facilitate precise scanning. When the current density remains unchanged, making the electron beam spot smaller means making the current of the electron beam smaller, which results in a longer direct writing time. On the other hand, when the size of the graphics to be directly written is below tens of nanometers, the smaller the line width, the more significant the impact of shot noise, which seriously affects the uniformity of the critical dimension and the roughness of the line edge.

[0004] It should be noted that the above introduction to the technical background is merely intended to provide a clear and complete description of the technical solutions of this application and facilitate understanding by those skilled in the art. Simply because these solutions are described in the background technology section of this application, it should not be assumed that the above technical solutions are well known to those skilled in the art.

[0005] Summary of the Invention

[0006] To ensure that the critical line width uniformity and line edge roughness of small line width patterns meet product performance requirements, smaller line widths require a less sensitive electron beam photoresist during direct writing. As a result, smaller line width patterns require a greater direct writing exposure. This means that, for a constant current density, smaller line widths require longer direct writing times. Increasing the current density is an effective way to improve the throughput of electron beam direct writing equipment per unit time.

[0007] However, the electron source of a typical multi-electron beam direct writing device consists of only a single electron source unit. A single source electron beam emitted from this single electron source unit is split into multiple (for example, sometimes exceeding 100,000) direct writing electron beams. To increase the current density of the direct writing electron beam, the total current of the source electron beams must be increased. However, increasing the total current of the source electron beams is difficult, and the increase in the current density of each direct writing electron beam is very limited.

[0008] The inventors of this application discovered that in a semiconductor device, not every level of structural graphics is very fine. For example, some levels of structural graphics are fine graphics that require fine direct writing, while some levels of structural graphics are relatively non-fine graphics that do not require the finest conditions for direct writing. In addition, even within the structural graphics of the same level, there are fine graphics and non-fine graphics. For graphics with a relatively large area or low requirements for the uniformity of the line width and the roughness of the line edges, if a larger electron beam spot and a larger current density can be used for direct writing, the direct writing time will be greatly shortened. However, general electron beam direct writing equipment cannot easily achieve a large-scale switching of the electron beam spot and current density while maintaining direct writing accuracy.

[0009] In order to solve the above problems or at least similar problems, an embodiment of the present application provides an electron beam direct writing device and an electron beam direct writing method. The electron beam direct writing device uses different electron source units to generate electron beams with beam spots of different areas, thereby ensuring the fineness of electron beam direct writing and improving the speed of electron beam direct writing.

[0010] The present invention provides an electron beam direct writing device, which includes:

[0011] an electron source, the electron source comprising a plurality of electron source units, each of the electron source units generating a corresponding electron beam; and

[0012] a controller for controlling the electron source to generate at least one electron beam;

[0013] The plurality of electron source units include at least one first electron source unit and at least one second electron source unit, the electron beam generated by each of the first electron source units corresponds to an electron beam having a first beam spot, and the electron beam generated by each of the second electron source units corresponds to an electron beam having a second beam spot.

[0014] The area of ​​the first beam spot is more than twice the area of ​​the second beam spot.

[0015] In another embodiment, the electron source unit comprises:

[0016] an electron emitting structure for generating an electron beam;

[0017] A dedicated circuit unit controls the time when the electron emission structure generates the electron beam and the current density of the electron beam based on the instruction of the controller.

[0018] In another embodiment, the current density of the electron beam having the first beam spot is more than twice the current density of the electron beam having the second beam spot.

[0019] In another embodiment, the electron beam direct writing device further comprises:

[0020] An electron beam shaping mechanism (6-i) shapes the electron beam generated by the electron source unit to form the electron beam having the first beam spot and the electron beam having the second beam spot.

[0021] In another embodiment, the electron beam direct writing device further comprises:

[0022] A workpiece stage (7) is used for carrying a substrate (8), and the workpiece stage moves under the control of the controller.

[0023] In another embodiment, the controller processes the received graphic data, divides the graphic into a first graphic and a second graphic, allocates the first electron source unit to the first graphic, allocates the second electron source unit to the second graphic,

[0024] The line width of the first graphic is greater than the line width of the second graphic.

[0025] In another embodiment, the controller controls the first electron source unit and the second electron source unit to generate electron beams simultaneously to form the first pattern and the second pattern.

[0026] In another embodiment, an electron beam direct writing method is provided. The method uses the electron beam direct writing device described in any one of the above embodiments to perform electron beam direct writing. The method includes:

[0027] The controller processes the received graphic data, divides the graphic into a first graphic and a second graphic, allocates the first electron source unit to the first graphic, and allocates the second electron source unit to the second graphic.

[0028] The line width of the first graphic is greater than the line width of the second graphic.

[0029] In another embodiment, the method further comprises:

[0030] The controller controls the first electron source unit and the second electron source unit to generate electron beams for electron beam direct writing to form the first pattern and the second pattern.

[0031] In another embodiment, the controller controls the first electron source unit and the second electron source unit to generate the electron beam simultaneously.

[0032] The beneficial effect of the present application is that the electron beam direct writing device uses different electron source units to generate electron beams with beam spots of different areas, thereby ensuring the fineness of the electron beam direct writing and improving the speed of the electron beam direct writing.

[0033] With reference to the following description and accompanying drawings, specific embodiments of the present application are disclosed in detail, indicating the manner in which the principles of the present application can be employed. It should be understood that the embodiments of the present application are not limited in scope. Within the spirit and scope of the appended claims, the embodiments of the present application include many variations, modifications and equivalents.

[0034] Features described and / or illustrated with respect to one embodiment may be used in the same or similar manner in one or more other embodiments, combined with features in other embodiments, or substituted for features in other embodiments.

[0035] It should be emphasized that the term "include / comprising" when used herein refers to the presence of features, integers, steps or components, but does not exclude the presence or addition of one or more other features, integers, steps or components. BRIEF DESCRIPTION OF THE DRAWINGS

[0036] The included drawings are used to provide a further understanding of the embodiments of the present application, which constitute a part of the specification, are used to illustrate the implementation methods of the present application, and together with the text description, explain the principles of the present application. Obviously, the drawings described below are only some embodiments of the present application. For those of ordinary skill in the art, other drawings can be obtained based on these drawings without inventive work. In the drawings:

[0037] FIG1 is a schematic diagram of the composition of an electron beam direct writing device according to an embodiment of the present application;

[0038] FIG2 is a schematic diagram of an electron beam direct writing method according to an embodiment of the present application;

[0039] FIG3 is a schematic diagram showing the composition of the electron source 1 . DETAILED DESCRIPTION

[0040] The above and other features of the present application will become apparent through the following description with reference to the accompanying drawings. In the description and the accompanying drawings, specific embodiments of the present application are disclosed in detail, which illustrate some embodiments in which the principles of the present application can be adopted. It should be understood that the present application is not limited to the described embodiments. On the contrary, the present application includes all modifications, variations and equivalents that fall within the scope of the appended claims.

[0041] Example 1

[0042] Embodiment 1 of the present application provides an electron beam direct writing device.

[0043] FIG1 is a schematic diagram of the composition of an electron beam direct writing device according to an embodiment of the present application. As shown in FIG1 , the electron beam direct writing device 100 according to the present application includes an electron source 1 and a controller 3 .

[0044] The electron source 1 includes a plurality of independently operable electron source units 1-i (1≤i≤N; N≥2; i and N are both positive integers; the same applies hereinafter). Each electron source unit 1-i can generate an electron beam 2, for example, an electron beam 2-ia, which can be referred to as an initial electron beam, corresponding to an incident electron beam 2-ib.

[0045] The electron source unit 1 - i includes an electron emission structure 4 - i and a dedicated circuit unit 5 - i that can control the generation time of the electron beam and the current density of the electron beam according to the instruction of the controller 3 .

[0046] The electron beam 2-ia is an initial electron beam generated by the electron source unit 1-i, and the electron beam 2-ib is an incident electron beam formed after the initial electron beam 2-ia is shaped by the corresponding electron beam shaping mechanism 6-i.

[0047] The shaping mechanism 6 - i may include at least one of an electron beam anode, a collimating lens, a deflector, and a focusing lens (not shown in the figure). In addition, the shaping mechanism 6 - i may also include other units.

[0048] The incident electron beam 2-ib can perform direct write exposure on the electron beam photoresist 9 on the substrate 8. The substrate 8 is fixed on the workpiece stage 7, and the workpiece stage 7 can move under the control of the controller 3, for example, the workpiece stage 7 can move in the horizontal direction.

[0049] In the present application, at least one electron source unit 1-k (1≤k≤N; k is a positive integer. The same applies hereinafter) is a large-spot electron source unit (i.e., a first electron source unit), which is used to form an initial electron beam of a large-spot electron beam (i.e., an electron beam having a first beam spot); and at least one electron source unit (electron units other than 1-k) is a small-spot electron source unit (i.e., a second electron source unit), which is used to form an initial electron beam of a small-spot electron beam (i.e., an electron beam having a second beam spot). The beam spot area of ​​the large-spot electron beam is more than twice the beam spot area of ​​the small-spot electron beam.

[0050] In addition, the current density of a large-spot electron beam can be more than twice that of a small-spot electron beam. The electron beam spot referred to here refers to the shape of the electron beam projection on the surface of the electron beam photoresist 9 on the substrate 8, formed by the incident electron beam 2-ib formed after the initial electron beam 2-ia passes through the electron beam shaping mechanism 6-i.

[0051] In one example, the number of electron source units in the electron source 1 is N = 10,000, approximately 1 / 50 of the electron source units are large beam spot electron source units (i.e., first electron source units), and the remaining approximately 49 / 50 of the electron source units are small beam spot electron source units (i.e., second electron source units); all electron source units are arranged roughly in an array, with the large beam spot electron source units evenly distributed in the electron source unit array. In addition, the present application is not limited to this. For example, in the electron source unit array of the electron source 1, the large beam spot electron source units can be concentrated together instead of being evenly distributed in the electron source unit array.

[0052] In the present application, the electron emission structure 4-i can be a nanocrystalline silicon field emission electron source, as described in reference 1 (reference 1: Japanese Journal of Applied Physics 61, SD0807 (2022), https: / / doi.org / 10.35848 / 1347-4065 / ac4ce1). The electron emission structure of reference 1 is suitable for a large-scale array multi-beam electron emission source because the current of each electron emission structure can be precisely controlled, which is more suitable for the formation of a small beam electron beam; alternatively, the electron emission structure 4-i can also be a silicon field emission electron source, as described in reference 2 (reference 2: IEEE Electron Device Letters, VOL. 37, NO. 1, JANUARY 2016, DOI: 10.1109 / LED.2015.2499440); alternatively, the electron emission structure 4-i can also be a gallium nitride field emission electron source, as described in reference 3 (reference 3: 2022 IEEE International Electron Devices Meeting (IEDM), DOI: 10.1109 / IEDM45625.2022.10019399). Both silicon field emission electron sources and gallium nitride field emission electron sources have the characteristics of providing high current density. Therefore, silicon field emission electron sources and gallium nitride field emission electron sources can be used to form large beam spot electron beams.

[0053] In one example, the electron source unit 1-k (e.g., the first electron source unit) is the silicon field emission electron source described in Reference 2, and the remaining electron source units 1-i (i≠k) (e.g., the second electron source unit) are the nanocrystalline silicon field emission electron sources described in Reference 1. The electron source units 1-k and 1-i (i≠k) can be integrated on the same substrate using semiconductor microfabrication technology, or they can be manufactured on different substrates and then integrated into a module.

[0054] As needed, the electron source 1 may include a plurality of large beam spot electron source units.

[0055] FIG3 is a schematic diagram of the components of the electron source 1. As shown in FIG3 , in at least one embodiment of the present application, the electron emission structures 4-i of each of the plurality of electron source units 1-i in the electron source 1 can be integrated on the first substrate 11 to form an electron source chip 101. For example, at least one electron emission structure 4-i is fabricated on a single chip, and multiple electron emission structures 4-i correspond to multiple single chips. These multiple single chips are integrated onto the first substrate 11 using bonding technology to form an electron source chip 101. Alternatively, at least one electron emission structure 4-i (e.g., all electron emission structures 4-i) can be fabricated on the first substrate 11 using the same manufacturing process (e.g., multiple electron emission structures 4-i are formed on a silicon substrate serving as the first substrate 11 using a microelectronics manufacturing process), thereby forming an electron source chip 101.

[0056] In at least one embodiment of the present application, the dedicated circuit units 5-i of each of the plurality of electron source units 1-i are integrated on the second substrate 12 to form a dedicated circuit chip 102. For example, at least one dedicated circuit unit 5-i is fabricated on a single chip, and multiple dedicated circuit units 5-i correspond to multiple single chips, which are then integrated onto the second substrate 12 using bonding technology to form a dedicated circuit chip 102; or, at least one dedicated circuit unit 5-i (e.g., all dedicated circuit units 5-i) are fabricated on the second substrate 12 using the same manufacturing process (e.g., multiple dedicated circuit units 5-i are formed on a silicon substrate serving as the second substrate 12 using a microelectronics manufacturing process), thereby forming a dedicated circuit chip 102.

[0057] The electron source chip 101 and the dedicated circuit chip 102 are electrically connected, thereby realizing electrical connection between the electron emission structure 4 - i and the dedicated circuit unit 5 - i in each electron source unit 1 - i.

[0058] The first substrate 11 and the second substrate 12 may be semiconductor substrates (eg, silicon substrates) or non-semiconductor substrates (eg, glass substrates, etc.).

[0059] As shown in FIG. 3 , the electron source chip 101 and the dedicated circuit chip 102 can be electrically connected by wire bonding, thereby simplifying the process.

[0060] The present application is not limited thereto, and the electron source chip 101 and the dedicated circuit chip 102 may also be electrically connected by substrate bonding, wherein the electron source chip 101 and the dedicated circuit chip 102 are stacked in the thickness direction to perform substrate bonding between the first substrate 11 and the second substrate 12 .

[0061] In some embodiments, substrate bonding includes substrate bonding using bumps. For example, a plurality of conductive bumps are provided on the surface or back side of at least one of the first substrate 11 and the second substrate 12, and each bump is electrically connected to the corresponding electron emission structure 4-i or dedicated circuit unit 5-i on the respective substrate. When the substrates are bonded, the mechanical and electrical connections of the first substrate 11 and the second substrate 12 are achieved through the bumps.

[0062] In some embodiments, substrate bonding may also include substrate bonding using through silicon vias (TSVs) and / or through glass vias (TGVs). For example, at least one of the first substrate 11 and the second substrate 12 is formed with a through silicon via (TSV) or a through glass via (TGV), and a conductive material is provided in the through silicon via or the through glass via, and the two sides of the substrates are electrically connected through the conductive material. Thus, in the case of substrate bonding, an electrical connection between the first substrate 11 and the second substrate 12 can be formed by, for example, a bump, and the two side surfaces of the first substrate 11 and / or the second substrate 12 are electrically connected through the conductive material provided in the through silicon via or the through glass via.

[0063] In the present application, the controller 3 can split the graphics that need to be directly written into non-fine graphics (i.e., the first graphics) and fine graphics (i.e., the second graphics), calculate the time for direct writing of the graphics, and improve the speed of direct writing while ensuring the accuracy of direct writing. For example, the controller 3 can divide the graphics into a first graphic and a second graphic (for example, the line width of the first graphic is greater than the line width of the second graphic), allocate a first electron source unit to the first graphic, and allocate a second electron source unit to the second graphic. For another example, when the controller 3 determines that direct writing of non-fine graphics with a large beam spot electron beam can improve the production capacity per unit time of the electron beam direct writing device 100, it can control the direct writing of non-fine graphics with a large beam spot electron beam, and use a small beam spot electron beam for direct writing of fine graphics.

[0064] In the present application, the controller 3 can control the timing and / or duration of the electron beam generation by the first electron source unit and the second electron source unit, thereby performing direct write exposure on the electron beam photoresist 9 to form the first pattern and the second pattern in the electron beam photoresist 9. For example, the first electron source unit and the second electron source unit generate the electron beam simultaneously, or the first electron source unit and the second electron source unit generate the electron beam sequentially, or the processes of the first electron source unit and the second electron source unit generating the electron beam at least partially overlap.

[0065] In this embodiment, substrate 8 can be a wafer commonly used in the semiconductor manufacturing field, such as a silicon wafer, a silicon-on-insulator (SOI) wafer, a silicon-germanium wafer, a germanium wafer, a gallium nitride wafer, a silicon carbide (SiC) wafer, etc. It can also be an insulating wafer such as quartz, sapphire, or glass. In addition, the surface of the substrate can further have various thin films and various structures required for semiconductor devices and micro-electromechanical systems (MEMS) devices. This embodiment is not limited to this. Substrate 8 can also be a mask commonly used in the semiconductor manufacturing field.

[0066] According to Example 1 of the present application, in an electron beam direct writing device, a small beam spot electron beam can be used to form fine patterns, and a large beam spot electron beam can be used to form non-fine patterns, thereby ensuring the direct writing accuracy while increasing the direct writing speed and improving the production capacity per unit time of the electron beam direct writing device.

[0067] Example 2

[0068] Embodiment 2 of the present application provides an electron beam direct writing method, which uses the electron beam direct writing device 100 described in Embodiment 1 to perform electron beam direct writing (ie, without using a mask plate, using an electron beam to directly form a pattern in the photoresist).

[0069] FIG2 is a schematic diagram of an electron beam direct writing method according to an embodiment of the present application. As shown in FIG2 , the electron beam direct writing method includes:

[0070] Operation 201: The controller processes received graphic data, divides the graphic into a first graphic and a second graphic, allocates the first electron source unit to the first graphic, and allocates the second electron source unit to the second graphic;

[0071] In operation 202 , the controller controls the first electron source unit and the second electron source unit to generate electron beams for electron beam direct writing to form the first pattern and the second pattern.

[0072] In operation 201 , the controller 3 processes the graphic data required for direct writing and divides the graphic data into a non-fine graphic (ie, a first graphic) and a fine graphic (ie, a second graphic).

[0073] In operation 202, the controller 3 controls the electron source 1 to directly write the pattern, while also controlling the workpiece stage 7 to perform the necessary scanning motion, i.e., the direct writing process. During the pattern direct writing process, fine patterns are directly written by the small-spot electron source unit. When the controller determines that the overall direct writing time can be shortened, at least a portion of non-fine patterns is directly written by the large-spot electron source unit. During the direct writing process, the small-spot electron source unit and the large-spot electron source unit can perform direct writing simultaneously.

[0074] In addition, as shown in FIG2 , the method may further include:

[0075] Operation 200: The controller receives the required direct-write graphic data and performs data processing.

[0076] For example, in operation 200 , the controller 3 may receive graphic data and perform necessary data processing on the graphic data to identify the graphic data.

[0077] According to Example 2 of the present application, a small-spot electron beam is used to form fine patterns, and a large-spot electron beam is used to form non-fine patterns, thereby ensuring the direct writing accuracy while increasing the direct writing speed and improving the production capacity per unit time of the electron beam direct writing equipment.

[0078] The present application has been described above in conjunction with specific embodiments. However, those skilled in the art should understand that these descriptions are merely illustrative and are not intended to limit the scope of protection of the present application. Those skilled in the art may make various modifications and variations to the present application based on the spirit and principles of the present application, and such modifications and variations are also within the scope of the present application.

Claims

1. An electron beam direct writing device, characterized in that: The electron beam direct writing device comprises: An electron source (1), comprising a plurality of electron source units (1-i), each of the electron source units generating a corresponding electron beam; and A controller (3) for controlling the electron source to generate at least one electron beam; The plurality of electron source units include at least one first electron source unit and at least one second electron source unit. The electron beam generated by each of the first electron source units corresponds to an electron beam having a first beam spot, The electron beam generated by each of the second electron source units corresponds to an electron beam having a second beam spot, The area of ​​the first beam spot is more than twice the area of ​​the second beam spot.

2. The electron beam direct writing device according to claim 1, characterized in that: The electron source unit comprises: an electron emitting structure for generating an electron beam; A dedicated circuit unit controls the time when the electron emission structure generates the electron beam and the current density of the electron beam based on the instruction of the controller.

3. The electron beam direct writing device according to claim 1, characterized in that: The current density of the electron beam having the first beam spot is more than twice the current density of the electron beam having the second beam spot.

4. The electron beam direct writing device according to claim 1, characterized in that: The electron beam direct writing device also includes: An electron beam shaping mechanism (6-i) shapes the electron beam generated by the electron source unit to form the electron beam having the first beam spot and the electron beam having the second beam spot.

5. The electron beam direct writing device according to claim 1, characterized in that: The electron beam direct writing device also includes: A workpiece stage (7) is used to carry a substrate (8), and the workpiece stage moves under the control of the controller.

6. The electron beam direct writing device according to claim 1, characterized in that: The controller processes the received graphic data, divides the graphic into a first graphic and a second graphic, allocates the first electron source unit to the first graphic, allocates the second electron source unit to the second graphic, The line width of the first graphic is greater than the line width of the second graphic.

7. The electron beam direct writing device according to claim 6, characterized in that: The controller controls the first electron source unit and the second electron source unit to simultaneously generate electron beams to form the first pattern and the second pattern.

8. An electron beam direct writing method, characterized in that: The method uses the electron beam direct writing device according to any one of claims 1 to 7 to perform electron beam direct writing, and the method comprises: The controller processes the received graphic data, divides the graphic into a first graphic and a second graphic, allocates the first electron source unit to the first graphic, allocates the second electron source unit to the second graphic, The line width of the first graphic is greater than the line width of the second graphic.

9. The electron beam direct writing method according to claim 8, characterized in that: The method further comprises: The controller controls the first electron source unit and the second electron source unit to generate electron beams for electron beam direct writing to form the first pattern and the second pattern.

10. The electron beam direct writing method according to claim 8, characterized in that: The controller controls the first electron source unit and the second electron source unit to simultaneously generate electron beams.

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