ELECTRON BEAM LITHOGRAPHY DEVICE AND LITHOGRAPHIC METHOD

• US 20140231668A1
• Filed: 09/27/2012
• Published: 08/21/2014
• Est. Priority Date: 10/03/2011
• Status: Active Grant

• Current Assignee: Param Corporation
• Original Assignee: Param Corporation
• Inventors: Yasuda, Hiroshi
• Granted Patent: US 8,878,143 B2
• Time in Patent Office: Days
• US Class Current: 250/396.R
• CPC Class Codes: B82Y 10/00 Nanotechnology for information processing, storage or transmission, e.g. quantum computing or single electron logic
• CPC Class Codes: B82Y 40/00 Manufacture or treatment of nanostructures
• CPC Class Codes: H01J 2237/0437 Semiconductor substrate
• CPC Class Codes: H01J 2237/31762 Computer and memory organisation
• CPC Class Codes: H01J 2237/31764 Dividing into sub-patterns
• CPC Class Codes: H01J 2237/31774 Multi-beam
• CPC Class Codes: H01J 37/045 Beam blanking or chopping, i.e. arrangements for momentarily interrupting exposure to the discharge
• CPC Class Codes: H01J 37/147 Arrangements for directing or deflecting the discharge along a desired path H01J37/045 take precedence; lenses H01J37/10
• CPC Class Codes: H01J 37/3007 Electron or ion-optical systems electron or ion-optical details H01J37/06 - H01J37/153
• CPC Class Codes: H01J 37/3026 Patterning strategy
• CPC Class Codes: H01J 37/3177 Multi-beam, e.g. fly's eye, comb probe

Abstract

A high-accuracy and high-speed lithographic pattern is acquired by forming a square lattice matrix beam group with an interval which is an integral multiple of a beam size in a two-dimensional plane, switching on and off the mesh of a device to be drawn by a bitmap signal, forming a desired beam shape, deflecting the beam to a necessary position, and radiating a beam with a whole blanker being opened after the beam state is stabilized. On and off signals and a vector scan signal of each beam are provided, and the whole blanker is released after the beam is stabilized, and thus high-accuracy and high-speed lithography is performed with a small amount of data. When the total number of shots exceeds a constant value, the pattern data are modified and high-speed lithography is achieved. A semiconductor reversed bias p-n junction technique is preferably used for an individual blanker electrode.

Claims

1. An electron beam lithographic method in which an electron beam lithography device is used for scanning a plurality of individual element beams on a specimen for lithography,

the electron beam lithography device comprising:

an electron gun which emits an electron beam in a Z-axis direction;

a shielding plate having a plurality of openings arranged in X and Y directions at a predetermined arrangement pitch, the shielding plate obtaining a plurality of individual element beams having a beam size which is restricted to a size of the opening from the electron beam emitted from the electron gun;

a plurality of individual blankers configured to turn the plurality of individual element beams obtained by the shielding plate ON/OFF individually;

a whole blanker configured to turn the plurality of individual element beams emitted from the plurality of individual blankers ON/OFF as a whole; and

a deflector which deflects the plurality of individual element beams having passed through the plurality of individual blankers and the whole blanker as a whole by every predetermined pitch, so as to scan the plurality of individual element beams stepwise with respect to the specimen,

the method comprising the steps of;

in a state in which emission of the plurality of individual element beams from the whole blanker is turned OFF, the deflector determining a direction of emission of the plurality of individual element beams, and, in accordance with a bitmap indicating ON/OFF of emission of the individual element beam from each individual blanker which is generated per shot in each emission direction, controlling the plurality of individual element blankers to control ON/OFF of the individual element beams emitted from the respective individual element blankers,

after processing for emitting the individual element beam from each individual blanker is settled, with the emission of the plurality of individual element beams from the whole blanker being turned ON, emitting to the specimen one shot formed by the individual element beams from the plurality of individual blankers in the ON state, and, with repetition of this one-shot emission formed by the plurality of individual element beams while shifting positions of the plurality of individual element beams by the deflector, drawing on the specimen a pattern in accordance with pattern data which is a target of lithography, and

generating the bitmap based on comparison between the pattern data and irradiation positions of the plurality of individual element beams onto the specimen that are determined in accordance with the arrangement pitch of the openings in the shielding plate, and, at the time of generating the bitmap, calculating the number of shots that is necessary for performing lithography corresponding to the pattern data, and when the number of necessary shots which is calculated exceeds the predetermined number, changing the pattern data.

2. The electron beam lithographic method according to claim 1, further comprising

assuming that the arrangement pitch of the plurality of individual blankers is P and a repetition pitch of a pattern in the pattern data is L, selecting an appropriate value of L such that a value obtained by dividing the least common multiple of P and L by L or P does not exceed a predetermined value, and modifying the pattern data to be drawn based on the value of L which is selected.

3. The electron beam lithographic method according to claim 1, further comprising:

providing a plurality of sets of the shielding plate and the individual blanker, with the arrangement pitch in the X and Y directions in each set being different from each other, and selecting one of the plurality of sets, for lithography, in accordance with the pattern data.

4. The electron beam lithographic method according to claim 1, further comprising:

externally supplying the bitmap data via a parallel serial data conversion circuit and storing the bitmap data as parallel data in a register through a deserializer.

5. The electron beam lithographic method according to claim 4, further comprising:

in a process in which the bitmap data are externally supplied via a parallel serial data conversion circuit and stored, as parallel data, in a register through a deserializer, employing laser optical communication using an optical fiber.

6. An electron beam lithography device for use in the electron beam lithographic method according to claim 1, wherein

the individual blanker includes a pair of electrodes for deflecting the individual element beam, and

in the pair of electrodes, an intrinsic semiconductor layer including SiC, Si, and the like, or a semiconductor depletion layer is used as an insulating film.

7. An electron beam lithography device, comprising:

an electron gun which emits an electron beam in a Z-axis direction;

a shielding plate having a plurality of openings arranged in X and Y directions at a predetermined arrangement pitch, the shielding plate obtaining a plurality of individual element beams having a beam size which is restricted to a size of the opening from the electron beam emitted from the electron gun;

a plurality of individual blankers configured to turn the plurality of individual element beams obtained by the shielding plate ON/OFF individually;

a whole blanker configured to turn the plurality of individual element beams emitted from the plurality of individual blankers ON/OFF as a whole;

a deflector which deflects the plurality of individual element beams having passed through the plurality of individual blankers and the whole blanker as a whole by every predetermined pitch, so as to scan the plurality of individual element beams stepwise with respect to the specimen; and

a control device which performs control such that in a state in which emission of the plurality of individual element beams from the whole blanker is turned OFF, a direction of emission of the plurality of individual element beams is determined by the deflector, and, in accordance with a bitmap indicating ON/OFF of emission of the individual element beam from each individual blanker which is generated per shot in each emission direction, the bitmap being generated based on comparison between the pattern data, which is a target of lithography, and irradiation positions of the plurality of individual element beams onto the specimen that are determined in accordance with the arrangement pitch of the openings in the shielding plate, the plurality of individual element blankers are controlled to control ON/OFF of the individual element beam emitted from each individual element blanker; and

, after processing for emitting the individual element beam from each individual blanker is settled, with emission of the plurality of individual element beams from the whole blanker being turned ON, one shot formed by the individual element beams from a plurality of individual blankers in the ON state is emitted to the specimen, and, with repetition of this one-shot emission formed by a plurality of individual beams while shifting positions of the plurality of individual element beams by the deflector, a pattern in accordance with pattern data which is a target of lithography is drawn on the specimen,

wherein

the individual blanker includes a pair of electrodes for deflecting the individual element beam, and

the pair of electrodes are formed using a semiconductor layer which is provided at a location of a P-type or N-type semiconductor substrate through which the individual element beam passes and in which N-type or P-type impurities which are of a type opposite the type of the semiconductor substrate are doped on a side surface of the opening.

8. The electron beam lithography device according to claim 7, wherein

a plurality of the semiconductor substrates are bonded together to form a blanking electrode which is elongated in a beam traveling direction.

9. The electron beam lithography device according to claim 7, wherein

in order to insulate wiring metals connected to the blanking electrode from each other, the wiring metal is covered with a PN junction diode, and the PN junction diode has a backward bias property so as to prevent electric current from flowing in the semiconductor substrate in the periphery when a voltage other than 0 voltage is applied to the wiring metal.

10. The electron beam lithography device according to claim 7, wherein

a multilayer wiring substrate is used for a wiring line for connection to the blanking electrode of each individual blanker, and

the total number of individual blankers is divided by an integer to separate the individual blankers into a plurality of small groups, wherein in each of the groups, wiring is performed in the same layer in the vertical direction and the horizontal direction.

11. The electron beam lithography device according to claim 7, wherein

wiring for connecting to the blanking electrode of each individual blanker is performed within one layer, and connection to another layer is performed by using a through hole.