JP5430703B2 - Drawing apparatus and article manufacturing method - Google Patents

Description

  The present invention relates to a drawing apparatus for drawing on a substrate with a plurality of charged particle beams, and an article manufacturing method.

  2. Description of the Related Art A drawing apparatus that performs drawing on a substrate by controlling deflection scanning and blanking of a charged particle beam such as an electron beam is known. This drawing apparatus can be employed as one of pattern formation techniques that replaces the light exposure method in the production of memory devices after 4GDRAM having a line width of 0.1 μm or less. As an example of this drawing apparatus, by illuminating an aperture member (aperture array) having a plurality of openings with a charged particle beam, and individually controlling a plurality of charged particle beams further formed through the respective openings, There is a multi-beam drawing apparatus that draws a desired pattern on a substrate. This multi-type drawing apparatus is advantageous in terms of throughput because the drawing area at one time, that is, the drawing area is wide. However, since the multi-type drawing apparatus performs batch irradiation corresponding to a large drawing area, it is necessary to irradiate a large current from a charged particle beam source. Therefore, there is a possibility that the electrode in the charged particle beam source evaporates and changes under the influence of heat during the current irradiation, and the irradiation position and irradiation area of the charged particle beam change. Therefore, Patent Document 1 efficiently adjusts the irradiation position and the irradiation area by detecting the beam current on the downstream side of the aperture or the substrate surface arranged downstream of the aperture member divided into a plurality of charged particle beams. A charged particle beam exposure apparatus that can be well implemented is disclosed.

Japanese Patent No. 3800343

  However, in the drawing apparatus shown in Patent Document 1, since it is necessary to put a detector in and out of the detection position every time the beam current is detected, the beam current cannot be detected in real time during drawing. Furthermore, this drawing apparatus cannot detect the irradiation position or irradiation area directly irradiated from the charged particle beam source. Therefore, it is difficult to determine whether the change due to the value detected by the detector is due to the irradiation position shift of the charged particle beam source or due to the influence of components such as a diaphragm.

  The present invention has been made in view of such a situation, and an object thereof is to provide a drawing apparatus that is advantageous for adjusting a charged particle beam that irradiates an aperture member, for example.

  In order to solve the above problems, the present invention is a drawing apparatus for drawing on a substrate with a plurality of charged particle beams, and a charged particle beam source and a lens that focuses the charged particle beam emitted from the charged particle beam source And an aperture member having a plurality of apertures that allow the charged particle beam focused by the lens to pass therethrough, and a detection unit that detects radiation generated from the aperture member by irradiation of the charged particle beam.

  ADVANTAGE OF THE INVENTION According to this invention, the drawing apparatus advantageous to adjustment of the charged particle beam which irradiates an opening member can be provided, for example.

It is a figure which shows the structure of the drawing apparatus which concerns on 1st Embodiment of this invention. It is a top view which shows the structure of the aperture array which concerns on 1st Embodiment. It is sectional drawing which shows the some structural example of the aperture array which concerns on 1st Embodiment. It is a flowchart which shows the flow of the adjustment sequence which concerns on 1st Embodiment. It is a figure which shows the structure of the drawing apparatus which concerns on 2nd Embodiment of this invention. It is a figure which shows the structure of the drawing apparatus which concerns on 3rd Embodiment of this invention.

  Hereinafter, embodiments for carrying out the present invention will be described with reference to the drawings.

(First embodiment)
First, a charged particle beam drawing apparatus (hereinafter referred to as “drawing apparatus”) according to a first embodiment of the present invention will be described. The drawing apparatus described in the present embodiment deflects (scans) a plurality of electron beams (charged particle beams), and individually controls blanking of the electron beam (irradiation OFF), thereby providing predetermined drawing data. Is a multi-beam type drawing apparatus for drawing at a predetermined position of the substrate to be processed. Here, the charged particle beam is not limited to the electron beam as in the present embodiment, and may be another charged particle beam such as an ion beam (ion beam).

  FIG. 1 is a schematic diagram illustrating a configuration of a drawing apparatus 1 according to the present embodiment. In each of the following drawings, the Z axis is taken in the nominal irradiation direction of the electron beam with respect to the substrate to be processed, and the X axis and Y axis perpendicular to each other are taken in a plane perpendicular to the Z axis. Moreover, in each following figure, the same code | symbol is attached | subjected to the same structure as FIG. The drawing apparatus 1 includes an electron source 2, an optical system 5 that divides, deflects, and forms an electron beam 4 emitted from a crossover 3 into a plurality of electron beams, a substrate stage 7 that holds a substrate 6 to be processed, A detector 8 and a control unit 9 that controls the operation of each component of the drawing apparatus 1 are provided. The substrate 6 to be processed is, for example, a wafer made of single crystal silicon, and a photosensitive resist is applied on the surface.

Here, the electron beam is attenuated immediately in an atmospheric pressure atmosphere, and the internal pressure of each component such as the electron source 2 and the optical system 5 is reduced by an evacuation system in order to prevent discharge due to a high voltage. Installed inside the conditioned vacuum vessel. For example, the drawing apparatus 1 first includes a first chamber 20 in which the electron source 2 is accommodated, a second chamber 21 in which the aperture array 31 and the blanking deflector array 33 in the optical system 5 are accommodated, and a deflector array. And a third chamber 22 for accommodating 35 and the like. Similarly, the drawing apparatus 1 also has a fourth chamber 23 that houses the substrate stage 7. In particular, the inside of the first chamber 20 is connected to an ion pump 24 and another vacuum pump 25 installed outside the first chamber 20 and is kept at a high degree of vacuum. It is about 5.0 * 10 < ^-7 > -3.0 * 10 < ^-6 > Pa in the state which is not irradiated. Further, the insides of the second to fourth chambers 21 to 23 are also connected to the vacuum pumps 26 to 28, respectively, and the degree of vacuum is lower than the inside of the first chamber 20, but is maintained at about 10 ⁻⁵ Pa level. .

The electron source (charged particle beam source) 2 is a so-called thermoelectron type in which a cathode electrode 10 of a dispenser cathode type (a cathode material is, for example, tungsten, impregnated barium oxide, calcium oxide, or aluminum oxide) is included in an electron emission portion. Is an electron source. The electron source 2 heats the cathode electrode 10 to about 1250 to 1450 K by supplying a current from an electron source control power supply 11 installed outside, and emits thermoelectrons. The emitted thermoelectrons are accelerated by applying a voltage of several kV by the anode electrode 13 with the beam current amount controlled by the Wehnelt electrode 12, and are emitted from the crossover 3 as an electron beam (electron beam bundle) 4. In FIG. 1, the trajectory of the electron beam 4 emitted from the crossover 3 is indicated by a dotted line. Further, the electron source 2 is not limited to such a dispenser cathode type, but may be a single crystal type such as a LaB6 type. In addition, the drawing apparatus 1 includes an aligner (deflector) 14 that can deflect the emitted electron beam 4 and direct the electron beam 4 on the downstream side of the electron source 2 in the first chamber 20. The aligner 14 is controlled by applying a desired voltage from a first voltage source 40 installed outside the first chamber 20.

  The optical system 5 is a projection system that projects the electron beam 4 emitted from the electron source 2 onto the substrate 6 to be processed. The optical system 5 includes, in order from the electron source 2 side, a collimator lens 30, an aperture array 31, a first electrostatic lens array 32, a blanking deflector array 33, a blanking stop 34, a deflector array 35, and a second. An electrostatic lens 36 is included. Further, the optical system 5 is provided adjacent to the third electrostatic lens 37 installed between the blanking deflector array 33 and the blanking diaphragm 34 and between the blanking diaphragm 34 and the deflector array 35. A fourth electrostatic lens 38 and a fifth electrostatic lens 39 are included. First, the collimator lens 30 is an electromagnetic lens that collimates (converges) the electron beam 4 diverged by the crossover 3 to obtain an area beam having a desired size. The collimator lens 30 is controlled by applying a desired voltage from a second voltage source 41 installed outside the second chamber 21. The collimator lens 30 may be an electrostatic lens. The aperture array 31 is an aperture member having a plurality of circular apertures (aperture rows) arranged in a matrix, and divides the electron beam 4 incident substantially perpendicularly from the collimator lens 30 into a plurality of electron beams. The configuration of the aperture array 31 will be described in detail below. The first electrostatic lens array 32 is a lens composed of three electrode plates having a circular opening (in the figure, the three electrode plates are shown integrally), and the blanking deflector array 33. The electron beam 4 is imaged (converged) on the top. The blanking deflector array 33 is composed of blanking deflectors arranged in a matrix, and performs an ON (non-blanking state) / OFF (blanking state) operation of irradiation of each electron beam 4. The blanking diaphragm 34 shields a desired electron beam 4 deflected from the electron beams 4 that have passed through the blanking deflector array 33 and focused by the third electrostatic lens 37. The deflector array 35 deflects (scans) the electron beam 4 that has passed through the fourth and fifth electrostatic lenses 38 and 39 in the X-axis direction on the surface of the substrate 6 to be processed placed on the substrate stage 7. . Further, the second electrostatic lens 36 images (converges) the electron beam 4 that has passed through the deflector array 35 on the substrate 6 to be processed.

  The substrate stage 7 is a substrate holder that moves the substrate 6 to be processed in at least two XY directions while holding the substrate 6 by electrostatic attraction, for example. The movement position of the substrate stage 7 is measured in real time by an unillustrated interferometer (laser length measuring device) or the like.

  The light detector (detection unit) 8 can detect light having a specific wavelength whose intensity changes depending on the irradiation position (or irradiation area) of the electron beam 4 when the aperture array 31 is irradiated with the electron beam 4. The two-dimensional synchrotron radiation detector. For example, since heat is generated when the electron beam 4 is irradiated to a specific area of the aperture array 31, the photodetector 8 of the present embodiment detects infrared light emitted due to the heat. It is desirable to make it. In the first chamber 20, a transmission window 42 that allows infrared light from the aperture array 31 to pass is installed on the upstream flange where the electron source 2 is installed. The photodetector 8 is installed on the atmosphere side of the transmission window 42 so as to receive infrared light through the transmission window 42. Here, in the first chamber 20, apart from the aperture array 31, there is a cathode electrode 10 that can be a radiation source of infrared light. Therefore, in this embodiment, the outer peripheral portion of the electron source 2 is covered with a shielding plate (shielding portion) 43 other than the electron beam irradiation port so as to prevent detection of infrared light from the cathode electrode 10 by the photodetector 8. It has been broken. Further, the photodetector 8 transmits (inputs) the detection result to the image processing unit 44. The image processing unit 44 calculates the center position (X, Y) of the electron beam irradiation and the irradiation size (irradiation area) S.

  As described above, the photodetector 8 detects infrared light radiated from the aperture array 31. In order to efficiently perform this detection, the aperture array 31 preferably has the following configuration. . FIG. 2 is a schematic top view showing the aperture array 31. FIG. 3 is a schematic cross-sectional view showing a plurality of configuration examples of the aperture array 31. First, as shown in FIG. 2, the aperture array 31 has nine openings arranged in a 3 × 3 region that is a region through which the electron beam 4 passes in a region 31 a irradiated with the electron beam 4 (region parallel to the XY plane). It is assumed that (aperture) 31b is provided. In this case, the aperture array 31 divides the electron beam 4 incident from the collimator lens 30 into nine. Note that the aperture array 31 can actually be applied with a numerical aperture of several thousand to 100,000. Next, as a first configuration example, first, the aperture array 31 shown in FIG. 3A has a high emissivity (infrared emissivity of about 0.8), such as molybdenum, and a heat-resistant metal. As a material. Next, as a second configuration example, the aperture array 31 shown in FIGS. 3B and 3C emits radiation different in a desired (designed value) region irradiated with the electron beam 4 and a non-irradiated region. It is composed of a combination of at least two materials having a rate. This is because the photodetector 8 facilitates detection of infrared light when the electron beam 4 is irradiated on a desired region of the aperture array 31, and is formed of, for example, a material having a high emissivity. It is desirable to combine the first member and the second member formed of a material having a low emissivity. In particular, in the aperture array 31 shown in FIG. 3B, the first member 50 in a desired region is formed of a metal material having a high emissivity (for example, molybdenum). On the other hand, the second member 51 around the first member 50 is formed of a metal material having a low emissivity (for example, tungsten, infrared emissivity of about 0.1). On the other hand, the material shown in FIG. 3B is reversed in the first member 50 and the second member 51 in the aperture array 31 shown in FIG. Furthermore, as a third configuration example, the aperture array 31 shown in FIG. 3D changes the emissivity depending on the region by changing the surface roughness (shape) of the material without using two different types of materials. It is set as the structure to be made. In this example, in order to emit infrared light in a specific direction (direction toward the photodetector 8), the surface structure of the first member (in this case, the entire upper surface of the aperture array 31) 52 has a certain directivity ( (Angle).

  The control unit 9 is configured by, for example, a computer, is connected to each component of the drawing apparatus 1 via a line, and can control each component according to a program or the like. The control unit 9 of this embodiment executes at least an irradiation position or irradiation area adjustment sequence of an electron beam 4 described later. Note that the control unit 9 may be configured integrally with other parts of the drawing apparatus 1 (in a common housing), or separate from the other parts of the drawing apparatus 1 (in another housing). It may be configured.

  Next, adjustment of the irradiation position and irradiation area of the electron beam 4 using the photodetector 8 will be described. In a multi-type drawing apparatus such as the drawing apparatus 1, a large current is irradiated from an electron source in order to perform batch irradiation corresponding to a large drawing area. By performing such a drawing process for a certain period (arbitrary period), the electrode in the electron source evaporates and changes due to the influence of heat upon current irradiation. This means that the irradiation position and irradiation area of the electron beam may change depending on the usage period of the drawing apparatus (particularly the electron source). Therefore, the drawing apparatus 1 of the present embodiment adjusts the irradiation position and irradiation area of the electron beam 4 as described below after an arbitrary period has elapsed since the start of use of the apparatus.

  FIG. 4 is a flowchart showing the flow of an adjustment sequence for adjusting the irradiation position and irradiation area of the electron beam 4 in the present embodiment. First, when the adjustment sequence is started, the control unit 9 irradiates a desired electron beam 4 from the electron source 2 (step S100). At this time, the aperture array 31 generates heat by emitting the electron beam 4 and emits infrared light. Next, the control unit 9 causes the photodetector 8 to detect infrared light emitted from the aperture array 31 (step S101). Then, the detection result (two-dimensional temperature profile) in step S101 is transmitted to the image processing unit 44. Next, the control unit 9 causes the image processing unit 44 to extract a detected temperature or higher than the preset temperature, and based on the extracted detection result, the center position of electron beam irradiation ( X1, Y1) and the irradiation size S1 are calculated (step S102). Next, the control unit 9 determines the difference between the electron beam irradiation center position (X1, Y1) obtained in step S102 and the preset design electron beam irradiation center position (X0, Y0). Is calculated (step S103). Next, the control unit 9 determines whether or not the difference calculated in step S103 is within an acceptable desired value (step S104). At this time, when the control unit 9 determines that the difference is equal to or less than a desired value (YES), the control unit 9 proceeds to the following step S105. On the other hand, if the controller 9 determines that the difference does not fall below the desired value, that is, the error is large (NO), the controller 9 proceeds to step S107, which is an aligner adjustment step. In step S107, the control unit 9 determines an output voltage value to be set in the first voltage source 40 so that the difference is small, and changes the deflection state by applying the output voltage value to the aligner 14 by the first voltage source 40. The irradiation position of the electron beam 4 is corrected. After completion of step S107, the control unit 9 proceeds to step S101 again and confirms whether the difference in the center position is within a desired value or less. Next, in step S105, the control unit 9 calculates a difference between the irradiation size S1 of the electron beam irradiation obtained in step S102 and the preset irradiation size S0 of the designed electron beam irradiation. Next, the control unit 9 determines whether or not the difference calculated in step S105 falls within an allowable desired value or less (step S106). At this time, when the control unit 9 determines that the difference is equal to or less than a desired value (YES), the adjustment sequence is terminated. On the other hand, when the control unit 9 determines that the difference does not fall below the desired value, that is, it is large (NO), the control unit 9 proceeds to step S108 which is a collimator lens adjustment step. In step S108, the control unit 9 determines the output voltage value to be set to the second voltage source 41 so that the difference is small, and changes the focusing state by applying the output voltage value to the collimator lens 30 by the second voltage source 41. Then, the irradiation area of the electron beam 4 is corrected. After completion of step S108, the control unit 9 proceeds to step S101 again and confirms whether the difference in irradiation size is within a desired value or less.

  As described above, according to the configuration in which the photodetector 8 is installed, the irradiation information of the electron beam 4 can be obtained with high accuracy even during the normal operation (during drawing) of the drawing apparatus 1. According to the adjustment sequence using the light detector 8, the irradiation position or irradiation area of the electron beam 4 can be quickly adjusted (corrected) from the obtained irradiation information. 1 is advantageous in terms of improving the productivity.

  As described above, according to the present embodiment, it is possible to provide a drawing apparatus that is advantageous for adjusting the electron beam 4 that irradiates the aperture array 31.

(Second Embodiment)
Next, a drawing apparatus according to the second embodiment of the present invention will be described. The feature of the drawing apparatus of the present embodiment is that the installation position of the photodetector 8 shown in the first embodiment is changed. FIG. 5 is a schematic diagram showing the configuration of the drawing apparatus 60 of the present embodiment specialized in the components of the first chamber 20 and the second chamber 21 of the drawing apparatus 1 according to the first embodiment shown in FIG. . In FIG. 5, the same components as those of the drawing apparatus 1 shown in FIG. As shown in FIG. 5, the drawing device 60 first includes a transmission window 61 on the side surface of the second chamber 21 so that the upper surface of the aperture array 31 (the irradiation region of the electron beam 4) can be observed. Furthermore, the drawing apparatus 60 includes a photodetector 62 corresponding to the photodetector 8 of the first embodiment on the atmosphere side of the transmission window 61. According to this configuration, the influence of infrared light from the cathode electrode 10 on the photodetector can be further suppressed. Further, it is known that the emissivity of the substance is almost constant from 0 ° to 50 ° in the front, but starts to decrease when it exceeds 50 °, and rapidly decreases from 60 °. Therefore, infrared light traveling toward the photodetector 62 by adjusting the directivity in combination with the aperture array 31 in which a large number of protrusions having a certain angle are formed on the surface of the member as shown in FIG. The infrared light can be detected by the photodetector 62 more efficiently.

(Third embodiment)
Next, a drawing apparatus according to the third embodiment of the present invention will be described. The feature of the drawing apparatus of this embodiment is that the installation position of the photodetector 8 shown in the first embodiment is changed. FIG. 6 is a schematic diagram showing a configuration of the drawing apparatus 70 of the present embodiment specialized in the components of the first chamber 20 and the second chamber 21 of the drawing apparatus 1 according to the first embodiment shown in FIG. . In FIG. 5, the same components as those of the drawing apparatus 1 shown in FIG. In each of the above embodiments, the photodetector 8 (62) is installed on the atmosphere side. On the other hand, in this drawing apparatus 70, the photodetector 71 is installed inside the first chamber 20 and toward the aperture array 31 in the second chamber 21, as shown in FIG. . Here, the inside of the first chamber 20 requires a vacuum degree of 10 ⁻⁶ Pa or less as described above. Therefore, if the photodetector 71 is installed as it is in the first chamber 20, impurities contained in the photodetector 71 may be vaporized and released into the first chamber 20. Therefore, it is desirable that the photodetector 71 be installed while being accommodated in a dedicated sealed container 72 having a transmission window (transmission member) (not shown). According to this configuration, the photodetector 71 can be installed in the relatively vicinity of the aperture array 31, so that the infrared light can be detected more efficiently by the photodetector.

  In each of the above embodiments, the photodetector has been described as receiving infrared light caused by the heat generated in the aperture array 31, but the present invention is not limited to this. For example, it is assumed that the aperture array 31 in which the first member 51 shown in FIGS. 3B and 3C is a phosphor is employed, and the fluorescence wavelength light is emitted by irradiation of the electron beam 4. If the photodetector detects this fluorescence, it is not necessary to consider the influence of infrared light from the cathode electrode 10. Further, in the adjustment sequence shown in FIG. 4, it has been described that the irradiation position and irradiation area of the electron beam 4 are continuously adjusted. However, this adjustment sequence includes the adjustment of only one of them. obtain. Further, in each of the above embodiments, the control of the aligner 14 and the collimator lens 30 has been described as changing the electric field by changing the voltage as an example, but for example, changing the magnetic field by changing the current. There may be.

(Product manufacturing method)
The method for manufacturing an article according to an embodiment of the present invention is suitable for manufacturing an article such as a micro device such as a semiconductor device or an element having a fine structure. The manufacturing method includes a step of forming a latent image pattern on the photosensitive agent on the substrate coated with the photosensitive agent using the above drawing apparatus (a step of drawing on the substrate), and the latent image pattern is formed in the step. Developing the substrate. Further, the manufacturing method may include other well-known steps (oxidation, film formation, vapor deposition, doping, planarization, etching, resist stripping, dicing, bonding, packaging, and the like). The method for manufacturing an article according to the present embodiment is advantageous in at least one of the performance, quality, productivity, and production cost of the article as compared with the conventional method.

  As mentioned above, although preferable embodiment of this invention was described, this invention is not limited to these embodiment, A various deformation | transformation and change are possible within the range of the summary.

DESCRIPTION OF SYMBOLS 1 Drawing apparatus 2 Electron source 4 Electron beam 6 Substrate 8 Optical detector 30 Collimator lens 31 Aperture array

Claims (10)

A drawing apparatus for drawing on a substrate with a plurality of charged particle beams,
A charged particle beam source;
A lens that focuses the charged particle beam emitted from the charged particle beam source;
An aperture member having a plurality of apertures through which the charged particle beam focused by the lens passes;
A detector that detects radiation generated from the aperture member by irradiation of the charged particle beam;
A drawing apparatus comprising:   The drawing apparatus according to claim 1, further comprising: a control unit that controls the lens so that a focused state of the charged particle beam by the lens changes based on an output of the detection unit. A deflector that is disposed between the charged particle beam source and the lens and deflects the charged particle beam emitted from the charged particle beam source;
A control unit for controlling the deflector so that a deflection state by the deflector changes based on an output of the detection unit;
The drawing apparatus according to claim 1, further comprising:   The drawing apparatus according to claim 1, wherein the radiation is infrared light.   The drawing apparatus according to claim 4, wherein the opening member includes a plurality of regions having different emissivities of infrared light. The aperture member has a surface structure in which the radiation has directivity,
The drawing device according to claim 1, wherein the detection unit is arranged according to the directivity. The opening member includes a phosphor,
The drawing apparatus according to claim 1, wherein the radiation is fluorescence generated from the phosphor. The opening member is disposed inside a vacuum vessel provided with a transmission member that transmits the radiation,
The drawing device according to claim 1, wherein the detection unit is disposed outside the vacuum container and detects the radiation through the transmission member. The opening is disposed inside the vacuum vessel,
The said detection part is accommodated in the inside of the airtight container provided with the permeation | transmission member which permeate | transmits the said radiation, and is arrange | positioned inside the said vacuum vessel, The said radiation is detected through the said permeation | transmission member, It is characterized by the above-mentioned. Item 8. The drawing apparatus according to any one of Items 1 to 7. Drawing on a substrate using the drawing apparatus according to any one of claims 1 to 9,
Developing the substrate on which the drawing has been performed in the step;
A method for producing an article comprising:

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