Electron source module and electron beam direct writing machine

Abstract

An electron source module (10) and an electron beam direct writing machine. The electron source module (10) comprises: an array-type electron source substrate (1), wherein a plurality of electron emission units (2) are formed on a first main surface (1-1) of the array-type electron source substrate (1); and a local temperature control mechanism (3), which is in contact with the array-type electron source substrate (1) and used for controlling the temperature of the array-type electron source substrate (1) not to be greater than a preset temperature value. The local temperature control mechanism (3) is arranged to control the temperature of the array-type electron source substrate (1) in the electron source module (10), greatly reducing the level of phonon scattering.

Description

Electron source module and electron beam direct writer Technical Field

[0001] The present application relates to the field of semiconductor technology, and in particular to an electron source module and an electron beam direct writing machine. 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 patterns (including patterns on photomasks and structural patterns at various device levels) requires both finer and more accurate direct writing and high-speed direct writing despite the dramatic increase in pattern data volume. To accurately write fine patterns, the electron beam spot size must be reduced to facilitate precise scanning. While maintaining a constant current density, reducing the electron beam spot size means reducing the electron beam current, which results in longer direct writing times. Furthermore, when the pattern size to be written is below tens of nanometers, the smaller the line width, the more significant the impact of shot noise, seriously impacting critical line width uniformity and line edge roughness. To ensure that critical line width uniformity and line edge roughness for small line width patterns meet product performance requirements, electron beam photoresists with lower sensitivity are used for smaller line widths during direct writing. Consequently, smaller line widths require larger direct writing exposures. This means that, while maintaining a constant current density, smaller line widths require longer direct writing times. To increase the throughput of electron beam direct writing equipment per unit time, a multi-beam direct writer, which uses multiple electron beams to write simultaneously, has become a necessary tool. To meet actual needs, a multi-beam direct writer needs to have hundreds of thousands of electron beams.

[0004] Currently, practical multi-electron beam direct writers generally use a single electron source, splitting the source electron beam emitted from this single electron source into multiple direct-writing electron beams. To increase the current density of the direct-writing electron beam, the total current of the source electron beam needs to be increased. However, increasing the total current of the source electron beam is difficult, and the increase in the current density of each direct-writing electron beam is relatively limited. Furthermore, since switching these split direct-writing electron beams cannot be performed at the source, beam blankers must be added to the electron optical system to allow or block the electron beams.

[0005] However, the introduction of the electron beam gate makes the entire electron beam direct writing machine system very complicated, and it is also easy to generate problems such as electrification near the electron beam gate. The electron source disclosed in Reference 1 (Reference 1: Japanese Journal of Applied Physics 61, SD0807 (2022), https: / / doi.org / 10.35848 / 1347-4065 / ac4ce1) adopts an array electron source. Each electron beam of this array electron source is emitted by a separate electron source unit. Therefore, in principle, the degree of freedom of the current of each electron source unit of the array electron source is very high. The electron emission of this array electron source is quasi-ballistic emission, which has the advantage that the initial energy distribution of the emitted electrons is relatively concentrated.

[0006] 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. Summary of the Invention

[0007] The inventors discovered that in a technical solution using an array electron source, a major factor affecting the initial energy distribution of emitted electrons is phonon scattering during electron transmission within the electron source device. The smaller the phonon scattering, the more concentrated the initial energy distribution of the emitted electrons. One of the most effective ways to reduce phonon scattering is to lower the temperature of the electron source device. Therefore, how to effectively reduce the temperature of the electron source device has become a problem that needs to be solved.

[0008] In order to solve the above problems or at least similar problems, the embodiments of the present application provide an electron source module and an electron beam direct writer, which are equipped with a local temperature control mechanism to control the temperature of the array electron source substrate in the electron source module, thereby significantly reducing the level of phonon scattering.

[0009] According to one aspect of an embodiment of the present application, there is provided an electron source module (10), comprising:

[0010] An array type electron source substrate (1), wherein a plurality of electron emission units (2) are formed on a first main surface (1-1) of the array type electron source substrate; and

[0011] A local temperature control mechanism (3) is in contact with the array-type electron source substrate (1) and controls the temperature of the array-type electron source substrate (1) to be no higher than a preset temperature value.

[0012] In some embodiments, the local temperature control mechanism comprises:

[0013] a temperature measuring unit (4) for measuring the temperature of the array-type electron source substrate (1);

[0014] a temperature control unit (5) which receives the temperature signal from the temperature measuring unit, compares the temperature signal with the preset temperature value and makes a heat exchange decision;

[0015] A heat exchange unit (6) controls the heat input and output of the array-type electron source substrate (1) through heat conduction according to the heat exchange decision.

[0016] In some embodiments, the heat exchange unit comprises:

[0017] a refrigerant control mechanism that controls the temperature and transport of the refrigerant according to the heat exchange decision; and

[0018] A heat exchanger (7), wherein the array electron source substrate (1) exchanges heat with the refrigerant through the heat exchanger.

[0019] The first main surface (7-1) of the heat exchanger (7) is in close contact with the second main surface (2-2) of the array electron source substrate (1), and the second main surface (7-2) of the heat exchanger is in close contact with the refrigerant; the refrigerant flows through the second main surface (7-2) of the heat exchanger under the control of the refrigerant control mechanism.

[0020] In some embodiments, the refrigerant is an insulating gas, an insulating liquid, or a mixture of an insulating gas and an insulating liquid.

[0021] In some embodiments, the cryogen includes liquid nitrogen or liquid helium.

[0022] In some embodiments, the first main surface of the heat exchanger (7) and the second main surface of the array electron source substrate (1) are in close contact with each other through semiconductor substrate bonding;

[0023] The bonding includes direct bonding or indirect bonding through an intermediate layer;

[0024] The intermediate layer is a bonding glue, or a metal including any one of copper, gold, tin and aluminum, or an alloy including two or more of copper, gold, tin, aluminum and germanium, or a semiconductor material including silicon or a silicon compound.

[0025] In some embodiments, the heat exchanger (7) is a microfluidic chip, and the microfluidic chip includes a plurality of microchannels formed on a silicon substrate;

[0026] The first main surface of the silicon substrate is in close contact with the second main surface of the array electron source substrate (1), and the second main surface of the silicon substrate is in close contact with the refrigerant;

[0027] The microchannel has an opening on the second main surface of the silicon substrate and extends toward the first main surface of the silicon substrate;

[0028] The microchannel penetrates the first main surface of the silicon substrate, or does not penetrate the first main surface of the silicon substrate.

[0029] In some embodiments, the width of the microchannel is between 10 micrometers and 200 micrometers, and the depth thereof is between 50 micrometers and 800 micrometers.

[0030] In some embodiments, the heat exchange unit includes a thermoelectric conversion device.

[0031] In some embodiments, the heat exchanger comprises metal plates.

[0032] In some embodiments, the thickness of the array electron source substrate (1) is between 50 microns and 400 microns.

[0033] In some embodiments, the preset temperature value is lower than 273K.

[0034] In some embodiments, an electron beam direct writer is provided, wherein the electron source of the electron beam direct writer has the electron source module described in any of the above embodiments.

[0035] The beneficial effect of the present application is that, by providing a local cooling mechanism, the temperature of the array electron source substrate is lowered to a level that can significantly reduce phonon scattering, thereby improving the consistency of the initial energy of electrons emitted by the electron source, thereby reducing the requirements for the electron optical system of the electron beam direct writer and improving the performance of the electron beam direct writer.

[0036] 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.

[0037] 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.

[0038] 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

[0039] 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:

[0040] FIG1 is a schematic diagram of an electron source module of the present application;

[0041] FIG2 is another schematic diagram of the electron source module of the present application;

[0042] FIG3 is another schematic diagram of the electron source module of the present application;

[0043] FIG. 4 is a schematic diagram of an example of a heat exchanger of the electron source module of the present application. DETAILED DESCRIPTION

[0044] 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.

[0045] In various embodiments of the application, "ON" of the electron source unit corresponds to the electron source unit emitting an electron beam, and "OFF" of the electron source unit corresponds to the electron source unit not emitting an electron beam.

[0046] In the description of each embodiment of the present application, for the convenience of description, the direction parallel to the surface of the array-type electron source substrate is called "horizontal", and the direction perpendicular to the surface of the array-type electron source substrate is called "longitudinal", and the dimension in the "longitudinal" direction can be called "height" or "thickness"; in the "longitudinal", the direction from the array-type electron source substrate to the electron source control circuit substrate is called the "up" direction, and the opposite direction of the "up" direction is the "down" direction.

[0047] It should be noted that the above-mentioned “up” and “down” directions are only for the convenience of explanation and do not limit the orientation or posture of the electron source module of the present application during manufacture or use.

[0048] Example

[0049] An embodiment of the present application provides an electron source module.

[0050] FIG1 is a schematic diagram of the electron source module of the present application. As shown in FIG1 , the electron source module 10 includes: an array-type electron source substrate 1 and a local temperature control mechanism 3 .

[0051] A plurality of electron emission units 2 are formed on a first main surface 1 - 1 of the array-type electron source substrate 1 , and each electron emission unit 2 can emit electrons.

[0052] The thickness of the array-type electron source substrate 1 is between 50 micrometers and 400 micrometers. In a special example, the thickness of the array-type electron source substrate 1 is 100 micrometers.

[0053] The local temperature control mechanism 3 contacts the arrayed electron source substrate 1, thereby controlling the temperature of the arrayed electron source substrate 1. For example, the local temperature control mechanism 3 controls the temperature of the arrayed electron source substrate 1 to no higher than a preset temperature value. This preset temperature value enables phonon scattering within the electron source units on the arrayed electron source substrate 1 to be significantly lower than room temperature. In some examples, the preset temperature value is lower than 273K, more specifically, lower than 100K; in a specific example, the preset temperature value is 77K.

[0054] Fig. 2 is another schematic diagram of the electron source module of the present application. Fig. 2 shows an implementation state of the local temperature control mechanism 3 included in the electron source module 10 of the present application.

[0055] In the embodiment shown in FIG2 , the local temperature control mechanism 3 includes a temperature measuring unit 4, a temperature control unit 5, and a heat exchange unit 6. The temperature measuring unit 4 is a temperature sensor in close contact with the arrayed electron source substrate 1. It measures the temperature of the arrayed electron source substrate 1 and transmits the temperature signal to the temperature control unit 5. The temperature control unit 5 receives the temperature signal from the temperature measuring unit 4, compares it with a preset temperature value, and makes a heat exchange decision. The heat exchange unit 6 controls the heat input and output of the arrayed electron source substrate 1 through heat conduction based on the heat exchange decision signal from the temperature control unit 5, thereby maintaining the temperature of the arrayed electron source substrate 1 near the preset temperature value.

[0056] In some examples, the heat exchange unit 6 may include a thermoelectric conversion device, and thus, by controlling the voltage or current of the thermoelectric conversion device to adjust the temperature of the thermoelectric conversion device, heat exchange is performed with the array-type electron source substrate 1. For example, by applying a certain voltage or current to the thermoelectric conversion device, the temperature of the thermoelectric conversion device is reduced or heat is absorbed by the thermoelectric conversion device, so that the thermoelectric conversion device can exchange heat with the array-type electron source substrate 1 to reduce the temperature of the array-type electron source substrate 1.

[0057] Fig. 3 is another schematic diagram of the electron source module of the present application. Fig. 3 shows an implementation state of the local temperature control mechanism 3 included in the electron source module 10 of the present application.

[0058] In the embodiment shown in FIG. 3 , the heat exchange unit 6 may include a heat exchanger 7 .

[0059] In some examples, the heat exchanger 7 may be a solid structure, which may include a metal plate. The metal plate has good thermal conductivity and facilitates heat exchange with the array-type electron source substrate 1. In addition, in some embodiments, the solid structure may also include a columnar array, which is conducive to improving the efficiency of heat exchange. The columnar array and the metal plate may be made of the same material.

[0060] In some embodiments, in addition to the heat exchanger 7, the heat exchange unit 6 may further include a refrigerant control mechanism (not shown). The refrigerant control mechanism includes a refrigerant temperature regulating mechanism and a refrigerant transport mechanism. For example, the refrigerant control mechanism can control the temperature and transport of the refrigerant according to the heat exchange decision of the temperature control unit 5. For the sake of simplicity, the refrigerant control mechanism and the refrigerant are not shown in this figure, and reference can be made to the refrigerant control mechanisms commonly used in semiconductor devices. The refrigerant is an insulating gas, or liquid, or a mixture thereof with good thermal conductivity and fluidity. Under certain requirements, the refrigerant has good electrical insulation. For example, the refrigerant includes liquid nitrogen or liquid helium.

[0061] The heat exchanger 7 is used to exchange heat between the arrayed electron source substrate 1 and the refrigerant, maintaining the temperature of the arrayed electron source substrate 1 near a predetermined value. For example, the first main surface 7-1 of the heat exchanger 7 is in close contact with the second main surface 1-2 of the arrayed electron source substrate 1, while the second main surface 7-2 of the heat exchanger 7 is in close contact with the refrigerant (not shown). The refrigerant flows through the second main surface 7-2 of the heat exchanger 7 under the control of the refrigerant control mechanism.

[0062] In this embodiment, the first main surface 7-1 of the heat exchanger 7 and the second main surface 1-2 of the array-type electron source substrate 1 are closely bonded via semiconductor substrate bonding. This bonding is either direct bonding between the two or indirect bonding via an intermediate layer. The intermediate layer is a bonding adhesive, or a metal including any one of copper, gold, tin, and aluminum, or an alloy including any two or more materials such as copper, gold, tin, aluminum, and germanium, or a semiconductor material including silicon and silicon compounds. Furthermore, the present application is not limited thereto, and the first main surface 7-1 of the heat exchanger 7 and the second main surface 1-2 of the array-type electron source substrate 1 may also be closely bonded via other methods.

[0063] FIG4 is another schematic diagram of the electron source module of the present application. FIG4 shows another embodiment of the electron source module 10 of the present invention. In the embodiment shown in FIG4 , the first main surface 7-1 of the heat exchanger 7 and the second main surface 1-2 of the array electron source substrate 1 are in close contact through a semiconductor substrate bonding method. The bonding is a direct bonding between the two, or an indirect bonding through an intermediate layer. The intermediate layer is a bonding glue, or a metal including any one of copper, gold, tin, and aluminum, or an alloy including any two or more materials such as copper, gold, tin, aluminum, and germanium, or a semiconductor material including silicon and silicon compounds.

[0064] Fig. 4 is a schematic diagram of an example of a heat exchanger of the electron source module of the present application. Fig. 4A) is a plan view of the heat exchanger 7, and Fig. 4B) is a cross-sectional view of the heat exchanger 7 along line AA'.

[0065] As shown in FIG4A) and B), in some examples, the heat exchanger 7 can be a microfluidic chip, which can include: a silicon substrate 8 and a plurality of microchannels 9 formed on the second main surface 8-2 of the silicon substrate 8. The microchannels 9 have openings on the second main surface 8-2 of the silicon substrate 8 and extend toward the first main surface 8-1 of the silicon substrate 8. The microchannels 9 may not penetrate the first main surface 8-1 of the silicon substrate, or they may penetrate the first main surface 8-1 of the silicon substrate 8. For example, the width of the microchannels 9 is between 10 microns and 200 microns, and the depth of the microchannels 9 is between 50 microns and 800 microns. In a special case, the thickness of the silicon substrate 8 is 500 microns, the width of the microchannels 9 is 50 microns, and the depth of the microchannels 9 is 400 microns.

[0066] During use, the first principal surface 8-1 of the silicon substrate 8 is in close contact with the second principal surface 1-2 of the array-type electron source substrate 1. The second principal surface 8-2 of the silicon substrate 8 is in close contact with the refrigerant, allowing the refrigerant to enter the microchannels 9. Because the silicon substrate 8 has good thermal conductivity, the microchannels 9 increase the contact area between the silicon substrate 8 and the refrigerant and bring the refrigerant closer to the array-type electron source substrate 1. This structure achieves higher thermal conductivity and facilitates heat exchange between the refrigerant and the array-type electron source substrate 1.

[0067] The present application also provides an electron beam direct writer, wherein the electron source of the electron beam direct writer includes the electron source module 10 described in the above embodiment.

[0068] In the present application, by providing a local cooling mechanism, the temperature of the array electron source substrate 1 is lowered to a level that can significantly reduce phonon scattering, thereby improving the consistency of the initial energy of electrons emitted by the electron source, thereby reducing the requirements for the electron optical system of the electron beam direct writer and improving the performance of the electron beam direct writer.

[0069] 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 source module (10), characterized in that: The electron source module includes: An array type electron source substrate (1), wherein a plurality of electron emission units (2) are formed on a first main surface (1-1) of the array type electron source substrate; and A local temperature control mechanism (3) is in contact with the array-type electron source substrate (1) and controls the temperature of the array-type electron source substrate (1) to be no higher than a preset temperature value.

2. The electron source module according to claim 1, wherein: The local temperature control mechanism includes: a temperature measuring unit (4) for measuring the temperature of the array-type electron source substrate (1); a temperature control unit (5) which receives the temperature signal from the temperature measuring unit, compares the temperature signal with the preset temperature value and makes a heat exchange decision; A heat exchange unit (6) controls the heat input and output of the array-type electron source substrate (1) through heat conduction according to the heat exchange decision.

3. The electron source module according to claim 2, characterized in that: The heat exchange unit comprises: a refrigerant control mechanism that controls the temperature and transport of the refrigerant according to the heat exchange decision; and A heat exchanger (7), wherein the array electron source substrate (1) exchanges heat with the refrigerant through the heat exchanger. The first main surface (7-1) of the heat exchanger (7) is in close contact with the second main surface (2-2) of the array electron source substrate (1), and the second main surface (7-2) of the heat exchanger is in close contact with the refrigerant; the refrigerant flows through the second main surface (7-2) of the heat exchanger under the control of the refrigerant control mechanism.

4. The electron source module according to claim 3, wherein: The refrigerant is an insulating gas, an insulating liquid, or a mixture of an insulating gas and an insulating liquid.

5. The electron source module according to claim 4, wherein: The refrigerant includes liquid nitrogen or liquid helium.

6. The electron source module according to claim 3, wherein: The first main surface of the heat exchanger (7) and the second main surface of the array electron source substrate (1) are in close contact with each other through semiconductor substrate bonding; The bonding includes direct bonding or indirect bonding through an intermediate layer; The intermediate layer is a bonding glue, or a metal including any one of copper, gold, tin and aluminum, or an alloy including two or more of copper, gold, tin, aluminum and germanium, or a semiconductor material including silicon or a silicon compound.

7. The electron source module according to any one of claims 3 to 6, characterized in that: The heat exchanger (7) is a microfluidic chip, and the microfluidic chip includes a plurality of microchannels formed on a silicon substrate; The first main surface of the silicon substrate is in close contact with the second main surface of the array electron source substrate (1), and the second main surface of the silicon substrate is in close contact with the refrigerant; The microchannel has an opening on the second main surface of the silicon substrate and extends toward the first main surface of the silicon substrate; The microchannel penetrates the first main surface of the silicon substrate, or does not penetrate the first main surface of the silicon substrate.

8. The electron source module according to claim 7, wherein: The width of the microchannel is between 10 micrometers and 200 micrometers, and the depth thereof is between 50 micrometers and 800 micrometers.

9. The electron source module according to claim 3, wherein: The heat exchange unit includes a thermoelectric conversion device.

10. The electron source module according to claim 3, wherein: The heat exchanger comprises metal plates.

11. The electron source module according to claim 1, wherein: The thickness of the array electron source substrate (1) is between 50 microns and 400 microns.

12. The electron source module according to claim 1, wherein: The preset temperature value is lower than 273K.

13. An electron beam direct writing machine, characterized in that: The electron source of the electron beam direct writer includes the electron source module according to any one of claims 1 to 12.

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