JP2019204898A - Multi-charged particle beam lithography apparatus, blanking aperture array for multi-charged particle beam lithography apparatus, operation method of multi-charged particle beam lithography apparatus, and multi-charged particle beam lithography method - Google Patents

Abstract

To recover a blanking aperture array from damage due to irradiation of charged particle beams while being mounted on a multi-charged particle beam lithography apparatus so that period of service of a blanking aperture array can be extended.SOLUTION: A charged particle beam lithography apparatus includes: an emission part that emits a charged particle beam; a molded aperture array that forms a multi-beam; and a blanking aperture array including a semiconductor substrate 300 on which a blanker for performing blanking deflection of each beam is provided. The blanking aperture array includes: a control circuit formed on the semiconductor substrate and controlling the blanker; and a heater H provided in a formation area of the control circuit.SELECTED DRAWING: Figure 3

Description

  The present invention relates to a multi-charged particle beam drawing apparatus, a blanking aperture array for a multi-charged particle beam drawing apparatus, an operation method of the multi-charged particle beam drawing apparatus, and a multi-charged particle beam drawing method.

  As LSIs are highly integrated, circuit line widths required for semiconductor devices have been reduced year by year. In order to form a desired circuit pattern on a semiconductor device, a reduction projection type exposure apparatus is used to form a high-precision original pattern pattern formed on quartz (a mask, or a pattern used particularly in a stepper or scanner is also called a reticle). )) Is reduced and transferred onto the wafer. A high-precision original pattern is drawn by an electron beam drawing apparatus, and so-called electron beam lithography technology is used.

  Since a drawing apparatus using a multi-beam can irradiate many beams at a time as compared with the case of drawing with one electron beam, the throughput can be greatly improved. In a multi-beam drawing apparatus using a blanking aperture array, which is one form of the multi-beam drawing apparatus, for example, an electron beam emitted from one electron gun is passed through a shaped aperture array having a plurality of apertures to form a multi-beam ( A plurality of electron beams). The multi-beams pass through corresponding blankers of the blanking aperture array. The blanking aperture array has an electrode pair for individually deflecting the beam, and an opening for passing the beam between them. One of the electrode pair (blanker) is fixed at the ground potential, and the other is ground potential and the other. By switching to this potential, blanking deflection of the passing electron beam is performed individually. The electron beam deflected by the blanker is shielded, and the electron beam not deflected is irradiated onto the sample.

  The blanking aperture array is equipped with a control circuit for independently controlling the electrode potential of each blanker. For this reason, the blanking aperture array chip is formed by MEMS processing the LSI chip on which the control circuit is formed to form electrode pairs and openings. That is, a control circuit is disposed immediately below the electrode and around the beam passage hole. For this reason, when forming a multi-beam with a shaped aperture array, scattered electrons scattered at the opening edge hit the control circuit mounted on the blanking aperture array, causing damage to the control circuit and causing leakage. There was a risk of increasing the current. A blanking aperture array in which a malfunction of the control circuit has occurred or a leakage current has increased cannot be used for the drawing process and has to be replaced.

JP-A-9-134869 JP 2000-252198 A JP-A-11-186144

  The present invention has been made in view of the above-described conventional situation, and while the blanking aperture array is mounted on the multi-charged particle beam drawing apparatus, the blanking aperture array is recovered from damage caused by irradiation of the charged particle beam. PROBLEM TO BE SOLVED: To provide a multi-charged particle beam drawing apparatus capable of extending the use period, a blanking aperture array for the multi-charged particle beam drawing apparatus, an operation method of the multi-charged particle beam drawing apparatus, and a multi-charged particle beam drawing method To do.

  A multi-charged particle beam drawing apparatus according to an aspect of the present invention includes a discharge unit that emits a charged particle beam and a plurality of first openings, and the region including the plurality of first openings is irradiated with the charged particle beam. In response, a shaped aperture array that forms a multi-beam by passing the charged particle beam through the plurality of first openings, and a corresponding beam among the multi-beams that have passed through the plurality of first openings. A blanking aperture array including a semiconductor substrate in which a plurality of second openings are formed, and each second opening is provided with a blanker for performing blanking deflection of the beam, and the blanking aperture array is formed on the semiconductor substrate. A control circuit that is formed and controls the blanker, and a heater provided in a formation region of the control circuit. .

  In the multi-charged particle beam lithography apparatus according to one aspect of the present invention, the control circuit includes a plurality of element isolation insulating films provided separately from each other, and an active element provided between the adjacent element isolation insulating films. The heater is provided apart from the active element in the depth direction of the semiconductor substrate or in the element isolation insulating film.

  A blanking aperture array for a multi-charged particle beam lithography apparatus according to an aspect of the present invention includes a semiconductor substrate having a plurality of openings through which a multi-beam passes, and a blanker provided in each of the openings and blanking-deflecting the multi-beam. And a control circuit which is formed on the semiconductor substrate and controls the blanker, and a heater which is provided in a formation region of the control circuit.

  An operation method of a multi charged particle beam drawing apparatus according to an aspect of the present invention includes a step of emitting a charged particle beam, a plurality of first openings, and the charged particle beam in a region including the plurality of first openings. The charged particle beam passes through the plurality of first apertures to form a multi-beam, and the corresponding multi-beams pass through the plurality of first apertures. A step of performing blanking deflection of each of the corresponding beams by a control circuit that controls a blanker provided in each of the plurality of second openings, a step of drawing at a desired position of the drawing object by the multi-beam, And the heater provided in the formation region of the control circuit generates heat during a predetermined diagnosis process.

  According to one aspect of the present invention, there is provided a multi-charged particle beam writing method, a step of emitting a charged particle beam, a plurality of first openings formed, and irradiation of the charged particle beam onto a region including the plurality of first openings. And a step of forming a multi-beam by passing the charged particle beam through the plurality of first openings, and a plurality of first beams through which the corresponding beams pass among the multi-beams that have passed through the plurality of first openings. The control circuit for controlling the blankers provided in the two openings respectively performs the blanking deflection of the corresponding beam and the multi-beam while generating heat in the heater provided in the formation area of the control circuit. Drawing at a desired position of the drawing object.

  ADVANTAGE OF THE INVENTION According to this invention, it can recover from the damage accompanying irradiation of a charged particle beam with mounting a blanking aperture array in a multi charged particle beam drawing apparatus, and can extend the use period of a blanking aperture array.

It is the schematic of the multi charged particle beam drawing apparatus which concerns on embodiment of this invention. It is a top view of a shaping | molding aperture array. FIG. 3 is a cross-sectional view of the transistor according to the same embodiment. It is a graph which shows the example of the change of leak current.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. In the embodiment, a structure using an electron beam will be described as an example of a charged particle beam. However, the charged particle beam is not limited to the electron beam, and may be an ion beam or the like.

  FIG. 1 is a schematic configuration diagram of a drawing apparatus according to an embodiment. The drawing apparatus shown in FIG. 1 is an example of a multi-charged particle beam drawing apparatus. The drawing apparatus includes a drawing unit 100 having an electron column 102 and a drawing chamber 103, a control computer 50, and a heater control unit 52. In the electron column 102, an electron gun 111, an illumination lens 112, a shaping aperture array 10, a blanking aperture array 30, a reduction lens 115, a limiting aperture member 116, an objective lens 117, and a deflector 118 are arranged.

  The blanking aperture array 30 is mounted (mounted) on the mounting substrate 40. An opening 42 through which an electron beam (multi-beam 130M) passes is formed at the center of the mounting substrate 40.

  An XY stage 105 is disposed in the drawing chamber 103. On the XY stage 105, a drawing target substrate 101 is arranged at the time of drawing. The substrate 101 may be an exposure mask for manufacturing a semiconductor device, or a semiconductor substrate (silicon wafer) on which the semiconductor device is manufactured. Further, the substrate 101 may be a mask blank coated with a resist and on which nothing is drawn yet.

  As shown in FIG. 2, openings (first openings) 12 in the vertical m rows × horizontal n rows (m, n ≧ 2) are formed in the molded aperture array 10 at a predetermined arrangement pitch. Each opening 12 is formed of a rectangle having the same size and shape. The shape of the opening 12 may be circular.

  The electron beam 130 emitted from the electron gun 111 (emission unit) illuminates the entire shaped aperture array 10 almost vertically by the illumination lens 112. The electron beam 130 passes through the plurality of openings 12 of the shaped aperture array 10 to form a plurality of electron beams (multi-beam 130M).

  The blanking aperture array 30 is provided below the molding aperture array 10, and a passage hole (second opening) 32 is formed in accordance with the arrangement position of each opening 12 of the molding aperture array 10. In each passage hole 32, a blanker made up of a pair of two electrodes is arranged. One of the blankers is fixed at the ground potential, and the other is switched to a potential different from the ground potential. The electron beam that passes through each passage hole 32 is independently deflected by a voltage applied to the blanker. In this way, the plurality of blankers perform blanking deflection of the corresponding beams among the multi-beams 130M that have passed through the plurality of openings 12 of the shaping aperture array 10.

  The multi-beam 130M that has passed through the blanking aperture array 30 is reduced by the reduction lens 115 and travels toward the hole in the center of the limiting aperture member 116. Here, the electron beam deflected by the blanker of the blanking aperture array 30 is displaced from the central hole of the limiting aperture member 116 and is blocked by the limiting aperture member 116. On the other hand, the electron beam that has not been deflected by the blanker passes through the hole in the center of the limiting aperture member 116. Blanking control is performed by turning on / off the blanker, and on / off of the beam is controlled.

  The limiting aperture member 116 shields each beam deflected to be in a beam-off state by a plurality of blankers. A beam of one shot is formed by the beam that has passed through the limiting aperture member 116 formed from when the beam is turned on to when the beam is turned off.

  The multi-beams that have passed through the limiting aperture member 116 are focused by the objective lens 117 and become a pattern image with a desired reduction ratio. The entire multi-beam is deflected together in the same direction by the deflector 118, and is irradiated to each irradiation position on the substrate 101 of each beam. When the XY stage 105 is continuously moving, the beam irradiation position is controlled by the deflector 118 so as to follow the movement of the XY stage 105.

  The multi-beams irradiated at a time are ideally arranged at a pitch obtained by multiplying the arrangement pitch of the plurality of openings 12 of the shaping aperture array 10 by the desired reduction ratio described above. The drawing apparatus 100 performs a drawing operation by a raster scan method in which shot beams are continuously irradiated in order, and when drawing a desired pattern, unnecessary beams are controlled to be beam-off by blanking control.

  The control computer 50 performs a plurality of stages of data conversion processing on the drawing data to generate apparatus-specific shot data. In the shot data, the irradiation amount and irradiation position coordinates of each shot are defined.

  The control computer 50 outputs the dose of each shot to the deflection control unit (not shown) based on the shot data. The deflection controller obtains the irradiation time t by dividing the input irradiation amount by the current density. The deflection control unit controls the deflection voltage applied to the corresponding blanker so that the beam is turned on for the irradiation time t when performing the corresponding shot.

  The control computer 50 outputs the deflection position data to the deflection controller so that each beam is deflected to the position (coordinates) indicated by the shot data. The deflection control unit calculates the deflection amount and applies a deflection voltage to the deflector 118. Thereby, the multi-beams shot at that time are deflected together.

  As described above, in the blanking aperture array 30, each blanker performs blanking deflection of the corresponding beam. Therefore, the blanking aperture array 30 is provided with a control circuit for independently controlling the electrode potential of each blanker. The control circuit includes a transistor and a wiring.

  When the electron beam 130 passes through the aperture 12 of the shaped aperture array 10 to form the multi-beam 130M, the scattered electrons scattered at the aperture edge hit the control circuit mounted on the blanking aperture array and cause damage (positive) Hole may be charged). Such damage causes malfunction of the transistor such as an increase in leakage current.

  Therefore, in the present embodiment, a heater is provided in the vicinity of a transistor that is an active element constituting a control circuit that controls the blanker electrode potential of the blanking aperture array 30, and an annealing process (heat treatment) is performed using the heater. Recover damage. For example, by performing annealing at about 200 ° C. using a heater, the transistor can be regenerated from damage.

  FIG. 3 shows an example of the configuration of the transistors provided in the blanking aperture array 30. The transistor Tr includes impurity diffusion layers 306 and 308 to be a source electrode and a drain electrode, and a gate electrode 304 formed on the semiconductor substrate 300 between the impurity diffusion layer 306 and the impurity diffusion layer 308 with a gate insulating film 302 interposed therebetween. With. Illustration of wiring is omitted.

  The semiconductor substrate 300 is, for example, a silicon substrate. FIG. 3 shows an X direction and a Y direction that are parallel to the main surface of the semiconductor substrate 300 and orthogonal to each other, and a Z direction that is perpendicular to the main surface of the semiconductor substrate 300. The X direction corresponds to the gate length direction of the transistor Tr, and the Y direction corresponds to the channel width direction of the transistor Tr.

  The gate insulating film 302 is, for example, a silicon oxide film, and the gate electrode 304 is, for example, a polysilicon layer. A sidewall insulating film made of a silicon oxide film or a silicon nitride film may be provided on the side surface of the gate electrode 304.

  A plurality of element isolation insulating films 310 having an STI (Shallow Trench Isolation) structure are formed to extend in the Y direction at intervals. The element isolation insulating film 310 is, for example, a silicon oxide film. The transistor Tr is provided between the element isolation insulating films 310.

  The element isolation insulating film 310 can be formed by forming an element isolation groove in the semiconductor substrate 300, embedding the insulating film in the element isolation groove, and planarizing the surface of the insulating film by CMP (Chemical Mechanical Polishing). .

  An interlayer insulating film 312 is formed on the semiconductor substrate 300 so as to cover the transistor Tr. The interlayer insulating film 312 is, for example, a silicon oxide film.

  Accumulation of holes due to electron beam irradiation occurs frequently on the side surfaces of the element isolation insulating film 310 in particular. Therefore, the heater H is provided on the lower surface portion (bottom surface portion) of the element isolation insulating film 310 to efficiently perform the annealing process. For example, after forming the element isolation groove, the heater H is formed on the bottom surface of the groove. After the heater H is formed, an insulating film is embedded in the element isolation trench.

  As the heater H, for example, a micro heater that performs an annealing process by Joule heat generated by passing a current through a resistance heating element can be used. A thin metal film such as tungsten or nickel can be used for the resistance heating element.

  Supply of current to the heater H is controlled by the heater control unit 52. For example, the heater control unit 52 supplies an electric current to the heater H at the time of diagnosis periodically performed during drawing in the drawing apparatus, and performs an annealing process. Diagnosis periodically performed by the drawing apparatus is, for example, drift diagnosis for diagnosing the drift amount of the electron beam.

  As shown in FIG. 4, when the annealing process is not performed, the leakage current continues to increase with time, and the blanking aperture array cannot be used for a long time. On the other hand, when the annealing process is performed during the periodical diagnosis at times T1 and T2, damage can be recovered and leakage current can be suppressed.

  As described above, according to the present embodiment, by performing the annealing process using the heater H, the blanking aperture array can be recovered from the damage caused by the irradiation of the charged particle beam, and the use period of the blanking aperture array can be extended. it can.

  In the above-described embodiment, the example in which the heater H is provided on the lower surface portion of the element isolation insulating film 310 has been described. However, the installation location of the heater H is not limited thereto, and the upper surface portion of the element isolation insulating film 310 may be used. The inside of the semiconductor substrate 300 may be spaced apart in the depth direction.

  In the above-described embodiment, the example in which the annealing process is performed in the periodic diagnosis has been described. However, the annealing process may be performed all the time. For example, the annealing process may be continuously performed during the drawing process on the drawing target substrate 101 so that damage accumulation and recovery are balanced.

  In the above-described embodiment, an example in which a micro heater using a resistance element (resistance heating element) is used as the heater H has been described. However, an external heater (mini heater) may be attached to the blanking aperture array 30. Further, the annealing process may be performed using heat generated by the operation of the blanking aperture array 30.

  Note that the present invention is not limited to the above-described embodiment as it is, and can be embodied by modifying the components without departing from the scope of the invention in the implementation stage. In addition, various inventions can be formed by appropriately combining a plurality of constituent elements disclosed in the embodiment. For example, some components may be deleted from all the components shown in the embodiment. Furthermore, constituent elements over different embodiments may be appropriately combined.

DESCRIPTION OF SYMBOLS 10 Molding aperture array 30 Blanking aperture array 40 Mounting substrate 100 Drawing part 101 Substrate 102 Electronic lens tube 103 Drawing chamber 111 Electron gun

Claims (5)

An emission part for emitting a charged particle beam;
A plurality of first openings are formed, a region including the plurality of first openings is irradiated with the charged particle beam, and the charged particle beam passes through the plurality of first openings to form a multi-beam. Molded aperture array,
A semiconductor substrate in which a plurality of second openings through which the corresponding beams pass among the multi-beams that have passed through the plurality of first openings is formed, and a blanker that performs blanking deflection of the beam is provided in each second opening. Blanking aperture array with
With
The blanking aperture array is
A control circuit formed on the semiconductor substrate for controlling the blanker;
A heater provided in a formation region of the control circuit;
A multi-charged particle beam drawing apparatus comprising: The control circuit includes a plurality of element isolation insulating films provided separately from each other, and an active element provided between adjacent element isolation insulating films,
2. The multi-charged particle beam drawing apparatus according to claim 1, wherein the heater is provided apart from the active element in a depth direction of the semiconductor substrate or in the element isolation insulating film. A semiconductor substrate having a plurality of openings through which the multi-beams pass;
A blanker provided at each of the openings for blanking deflection of the multi-beam;
A control circuit formed on the semiconductor substrate for controlling the blanker;
A heater provided in a formation region of the control circuit;
A blanking aperture array for a multi-charged particle beam drawing apparatus. Emitting a charged particle beam;
A plurality of first openings are formed, a region including the plurality of first openings is irradiated with the charged particle beam, and the charged particle beam passes through the plurality of first openings to form a multi-beam. Process,
Among the multi-beams that have passed through the plurality of first openings, blanking deflection of each of the corresponding beams is performed by control circuits that respectively control blankers provided in the plurality of second openings through which the corresponding beams pass. A process of performing;
Drawing at a desired position of the drawing object by the multi-beam;
With
An operation method of a multi-charged particle beam drawing apparatus, wherein a heater provided in a formation region of the control circuit generates heat during a predetermined diagnostic process. Emitting a charged particle beam;
A plurality of first openings are formed, a region including the plurality of first openings is irradiated with the charged particle beam, and the charged particle beam passes through the plurality of first openings to form a multi-beam. Process,
Among the multi-beams that have passed through the plurality of first openings, blanking deflection of each of the corresponding beams is performed by control circuits that respectively control blankers provided in the plurality of second openings through which the corresponding beams pass. A process of performing;
Drawing at a desired position of the drawing object by the multi-beam while heating the heater provided in the formation region of the control circuit; and
A multi-charged particle beam writing method comprising:

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