Method for adjusting charged particle beam drawing apparatus, charged particle beam drawing apparatus, and program

Abstract

To provide a method for adjusting a charged particle beam drawing apparatus, a charged particle beam drawing apparatus, and a program, which can reduce a downtime without reducing maintenance.SOLUTION: An adjustment method for a charged particle beam drawing apparatus according to an embodiment is a method for adjusting a charged particle beam drawing apparatus in which an undrawn substrate received from outside via an interface unit is transported to a drawing chamber and placed on a stage, the substrate on the stage is irradiated with a charged particle beam to draw a pattern, and the substrate after drawing is transported from the drawing chamber to the outside via the interface unit, and at least a part of the adjustment work for the equipment of the charged particle beam drawing apparatus is performed while the substrate is being transported between the interface unit and the drawing chamber.SELECTED DRAWING: Figure 2

Description

[Technical field]

[0001] The present invention relates to a method for adjusting a charged particle beam drawing apparatus, a charged particle beam drawing apparatus, and a program. [Background technology]

[0002] As LSIs become more highly integrated, the circuit line width required for semiconductor devices is becoming finer year by year. To form the desired circuit pattern on a semiconductor device, a method is adopted in which a high-precision original pattern (mask, or particularly one used in steppers and scanners, called a reticle) formed on quartz is reduced and transferred onto a wafer using a reduction projection exposure apparatus. The high-precision original pattern is drawn by an electron beam drawing apparatus, and so-called electron beam lithography technology is used.

[0003] In electron beam lithography systems, electron beams are deflected by a deflector to perform drawing. A DAC (digital-analog converter) amplifier unit is used to deflect the electron beam. The role of beam deflection using such a DAC amplifier unit includes controlling the shape and size of the beam shot, controlling the shot position, and blanking the beam. In recent years, the accuracy (resolution, error, noise, etc.) required for the output of the DAC amplifier unit has been increasing in order to further fine the reticle patterns.

[0004] The characteristics of the components that make up the DAC amplifier unit change gradually over time, which can affect the output accuracy of the DAC amplifier unit and cause errors in the drawing pattern. For this reason, the operation of the DAC amplifier unit is diagnosed and adjusted to maintain output accuracy. Gain adjustment and linearity correction are known as methods for diagnosing and adjusting the DAC amplifier unit.

[0005] Diagnosis and adjustment of the DAC amplifier unit is performed during regular maintenance of the imaging device, which takes time, resulting in longer downtime for the imaging device and reduced productivity.

[0006] If maintenance is reduced in order to shorten the downtime of the imaging device, for example by reducing the frequency of regular maintenance, then defects in the imaging device, such as a decrease in the output accuracy of the DAC amplifier unit, may not be detected and production may continue, which may result in a deterioration in product quality. [Prior art documents] [Patent documents]

[0007] [Patent Document 1] JP 2019-084474 A [Patent Document 2] JP 2014-165202 A [Patent Document 3] Japanese Patent Publication No. 138732 / 1983 Summary of the Invention [Problem to be solved by the invention]

[0008] The present invention has been made in consideration of the above-described conventional situation, and has an object to provide a method for adjusting a charged particle beam drawing apparatus, a charged particle beam drawing apparatus, and a program that can reduce downtime without reducing maintenance. [Means for solving the problem]

[0009] According to one aspect of the present invention, there is provided a method for adjusting a charged particle beam drawing apparatus, which comprises transporting an undrawn substrate received from outside via an interface unit to a drawing chamber and placing it on a stage, irradiating a charged particle beam onto the substrate on the stage to draw a pattern, and transporting the substrate after drawing from the drawing chamber to the outside via the interface unit, and at least a part of the adjustment work for the equipment of the charged particle beam drawing apparatus is performed while the substrate is being transported between the interface unit and the drawing chamber.

[0010] A charged particle beam drawing apparatus according to one embodiment of the present invention comprises an interface unit that receives a substrate from outside and transports the substrate to the outside, a drawing chamber having a stage on which the substrate is placed and in which a charged particle beam is irradiated onto the substrate placed on the stage to draw a pattern, and a transport unit that transports the substrate between the interface unit and the drawing chamber, and performs at least a part of the adjustment work of the component equipment during the transport of the substrate between the interface unit and the drawing chamber.

[0011] A program according to one aspect of the present invention causes a computer of a charged particle beam drawing apparatus to execute the following processes: transporting an undrawn substrate received from outside through an interface unit of the charged particle beam drawing apparatus to a drawing chamber and placing it on a stage; irradiating a charged particle beam onto the substrate on the stage to draw a pattern; transporting the drawn substrate from the drawing chamber to the outside through the interface unit; and performing at least a part of the adjustment work of equipment of the charged particle beam drawing apparatus while the substrate is being transported between the interface unit and the drawing chamber. Effect of the Invention

[0012] According to the present invention, downtime can be reduced without reducing maintenance, and productivity can be improved. [Brief description of the drawings]

[0013] [Figure 1] 1 is a plan view of an electron beam drawing apparatus according to an embodiment of the present invention. [Diagram 2] FIG. 2 is a partial cross-sectional view of the electron beam drawing apparatus according to the embodiment. [Diagram 3] 11A and 11B are diagrams illustrating an example of the order of adjustment operations performed during transportation of a substrate. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0014] Hereinafter, an embodiment of the present invention will be described with reference to the drawings. In the embodiment, a configuration using an electron beam as an example of a charged particle beam will be described. However, the charged particle beam is not limited to an electron beam, and a beam using other charged particles such as an ion beam may be used.

[0015] Fig. 1 is a plan view of an electron beam lithography apparatus according to an embodiment of the present invention, and Fig. 2 is a cross-sectional view of a writing chamber (W chamber, lithography chamber) 400 and an electron beam tube 500 which are parts of the electron beam lithography apparatus. As shown in Figs. 1 and 2, the electron beam lithography apparatus includes an interface (I / F) unit 100, an input / output (I / O) chamber 200, a robot chamber (R chamber) 300, a W chamber 400, an electron beam tube 500, a control device 600, gate valves G1 to G3, etc. The electron beam tube 500 is not shown in Fig. 1.

[0016] The I / F unit 100 has a transfer robot (transfer arm) 110 that transfers the substrate M to be drawn, receives the substrate M from outside the electron beam drawing apparatus, and transfers it to a downstream chamber. In addition, the I / F unit 100 unloads the substrate M after drawing to the outside of the electron beam drawing apparatus.

[0017] The substrate M to be drawn includes an exposure mask used when manufacturing a semiconductor device, a semiconductor substrate (silicon wafer) on which a semiconductor device is manufactured, etc. The substrate M may also be a mask blank on which a resist is applied and on which nothing is yet drawn.

[0018] The I / O chamber 200 is a so-called load lock chamber for loading and unloading the substrate M while maintaining the inside of the R chamber 300 at a vacuum (low pressure). The I / O chamber 200 includes a vacuum pump 210 and a gas supply system 220, and a gate valve G1 is provided between the I / F unit 100 and the I / F chamber 200. The vacuum pump 210 is, for example, a dry pump or a turbo molecular pump, and evacuates the inside of the I / O chamber 200. The gas supply system 220 supplies a vent gas (for example, nitrogen gas or CDA) into the I / O chamber 200 when the I / O chamber 200 is brought to atmospheric pressure.

[0019] When evacuating the I / O chamber 200, a vacuum pump 210 connected to the I / O chamber 200 is used to evacuate the I / O chamber 200. When returning the pressure inside the I / O chamber 200 to atmospheric pressure, a vent gas is supplied from a gas supply system 220, and the pressure inside the I / O chamber 200 becomes atmospheric pressure. When evacuating the I / O chamber 200 and when returning it to atmospheric pressure, the gate valves G1 and G2 are closed.

[0020] The R chamber 300 includes a vacuum pump 310, an alignment chamber 320, a mask cover housing chamber 330, a transfer robot 340, and a soaking chamber 350. The R chamber 300 is connected to the I / O chamber 200 via a gate valve G2.

[0021] The vacuum pump 310 is, for example, a cryopump, a turbo molecular pump, etc. The vacuum pump 310 is connected to the R chamber 300, and maintains a high vacuum by evacuating the inside of the R chamber 300. The alignment chamber 320 is a chamber for positioning (aligning) the substrate M.

[0022] The mask cover accommodation chamber 330 is a chamber that accommodates the mask cover H and places the mask cover H on the substrate M. The mask cover H is conductive and has a frame-shaped frame with an opening in the center, on which multiple earth mechanisms (grounding pins) are provided. The size of the frame is slightly larger than the substrate M. The mask cover H is intended to discharge electric charges that accumulate on the substrate M due to irradiation with an electron beam.

[0023] The soaking chamber 350 is a chamber for performing a soaking process to adjust the temperature of the substrate M to the surrounding environment.

[0024] The transfer robot 340 transfers the substrate M between the I / O chamber 200 , the alignment chamber 320 , the mask cover housing chamber 330 , the soaking chamber 350 and the W chamber 400 .

[0025] The W chamber 400 includes a vacuum pump 410, an XY stage 420, and driving mechanisms 430A and 430B, and is connected to the R chamber 300 via a gate valve G3.

[0026] The vacuum pump 410 is, for example, a cryopump or a turbo molecular pump. The vacuum pump 410 is connected to the W chamber 400, and evacuates the inside of the W chamber 400 to maintain a high vacuum. The XY stage 420 is a stage on which the substrate M is placed. The driving mechanism 430A drives the XY stage 420 in the X direction. The driving mechanism 430B drives the XY stage 420 in the Y direction. The movement of the XY stage 420 is controlled by the control device 600.

[0027] 2, the electron beam column 500 includes an electron beam irradiation means including an electron gun 510, a blanking aperture 520, a first aperture 522, a second aperture 524, a blanking deflector 530, a shaping deflector 532, a main deflector 534, a sub-deflector 536, and lenses 540 (illumination lens (CL), projection lens (PL), objective lens (OL)), and irradiates an electron beam onto a substrate M placed on an XY stage 420. A mask cover H is set on the substrate M to be irradiated with the electron beam, but the mask cover H is not shown in FIG.

[0028] An electron beam 502, which is an example of a charged particle beam emitted from an electron gun 510, illuminates the entire first aperture 522 having a rectangular, for example, square hole by an illumination lens CL. Here, the electron beam 200 is first shaped into a rectangle, for example, a square. Then, the electron beam of the first aperture image that has passed through the first aperture 522 is projected onto the second aperture 524 by a projection lens PL. The position of the first aperture image on the second aperture 524 is controlled by a shaping deflector 532, and the beam shape and dimensions can be changed. Then, the electron beam of the second aperture image that has passed through the second aperture 524 is focused by an objective lens OL, deflected by a main deflector 534 and a sub-deflector 536, and irradiated onto a desired position of the substrate M on the moving XY stage 420. The electron beam drawing apparatus is a variable shaping type drawing apparatus.

[0029] An electron beam 502 emitted from an electron gun 510 is controlled by a blanking deflector 530 so that in the beam-on state, it passes through a blanking aperture 520, and in the beam-off state, it is deflected so that the entire beam is blocked by the blanking aperture 520. An electron beam that passes through the blanking aperture 520 from the beam-off state to the beam-on state until the beam is subsequently turned off constitutes one electron beam shot. The amount of irradiation of the electron beam per shot irradiated onto the substrate M is adjusted depending on the irradiation time of each shot.

[0030] The control device 600 is, for example, a computer, and has a function of controlling each chamber, gate valve, etc. The control device 600 also controls the deflection voltages applied to the blanking deflector 530, the shaping deflector 532, the main deflector 534, the sub-deflector 536, etc.

[0031] For example, the control device 600 generates shot data indicating the irradiation time, shot shape, and irradiation position of each shot, and outputs it to a deflection control circuit 610. The deflection control circuit 610 calculates deflection amount data for beam deflection, and outputs it to a DAC amplifier 620. The DAC amplifier 620 converts the deflection amount data, which is a digital signal, into an analog signal, amplifies it, and applies it to each deflector as a deflection voltage. Although only one DAC amplifier 620 is shown in Fig. 2, a DAC amplifier connected to each of the shaping deflector 532, the main deflector 534, and the sub-deflector 536 is provided.

[0032] The DAC amplifier 620 needs to be adjusted periodically to maintain the output accuracy. In the adjustment, for example, the DAC amplifier unit is instructed to output test data, the output value is measured, a parameter to be corrected is calculated from the measured value, and the parameter is used to perform gain adjustment for finely adjusting the reference voltage of the DAC amplifier, linearity correction, etc. The adjustment of the DAC amplifier 620 is performed under the control of the control device 600.

[0033] Conventionally, the adjustment work of the DAC amplifier 620 has been performed during regular maintenance of the drawing device. For example, regular maintenance is performed every six months, and the drawing device is stopped for, for example, about two days to perform the adjustment work of the DAC amplifier 620 and maintenance of other hardware. In other words, two days of downtime occurs every six months.

[0034] Therefore, in this embodiment, the adjustment work of the DAC amplifier 620 is performed while the substrate M is being transported, and at least a part of the adjustment work of the DAC amplifier 620 is omitted from the work performed in the regular maintenance, thereby reducing the amount of work in the regular maintenance. This reduces the work time for the regular maintenance, shortens the downtime of the drawing apparatus, and improves productivity. For example, it is possible to shorten the downtime due to regular maintenance from two days in the past to one day.

[0035] Here, "during transport of the substrate M" refers to the period from when the I / F unit 100 receives the substrate M before drawing from outside the electron beam drawing apparatus until the substrate M is placed on the XY stage 420 of the W chamber 400. Also, "during transport of the substrate M" refers to the period other than the drawing processing period from when the I / F unit 100 receives the substrate M before drawing from outside the electron beam drawing apparatus until the substrate M after drawing is carried out to outside the electron beam drawing apparatus.

[0036] In addition, the term "substrate M being transported" may refer not only to the time when substrate M is being transferred (not physically stopped) by transport robot 110, transport robot 340, etc., but also to the time when substrate M is physically stopped while undergoing soaking processes such as acclimatization to vacuum or temperature.

[0037] A DAC amplifier is provided for each deflector. Also, the main deflector 534 and the sub-deflector 536 have a plurality of electrodes, and a DAC amplifier is connected to each electrode. The order of the DAC amplifiers to be adjusted is determined according to the time that can be allocated to the adjustment work of the DAC amplifiers during the transportation of the substrate M.

[0038] For example, consider a case in which eight DAC amplifiers (MAMP1 to MAMP8) corresponding to the main deflector 534 are provided, and eight DAC amplifiers (SAMP1 to SAMP8) corresponding to the sub-deflector 536 are provided.

[0039] For example, if the adjustment work for one DAC amplifier can be performed during one (one) transfer of the substrate M, the adjustment work for the 16 DAC amplifiers (MAMP1 to MAMP8 and SAMP1 to SAMP8) is completed by transferring the substrate M 16 times (16 substrates).

[0040] When the time allocated to the adjustment work of the DAC amplifier during the transportation of the substrate M is shorter than the time required for the adjustment work of one DAC amplifier, the adjustment work of one DAC amplifier is divided and performed over the transportation of multiple (multiple) substrates M.

[0041] Table 1 shows an example of the time required for adjustment (gain adjustment and linearity correction) for each of the DAC amplifiers (MAMP1 to MAMP8) corresponding to the main deflector 534 and each of the DAC amplifiers (SAMP1 to SAMP8) corresponding to the sub-deflector 536.

[0042] [Table 1]

[0043] If the time that can be allocated to the adjustment work of the DAC amplifiers during the transportation of the substrate M is 5 minutes, the gain adjustment and linearity correction for MAMP1 to MAMP8 take a total of 5 minutes, so the adjustment work for one MAMP is completed during one transportation.

[0044] On the other hand, for SAMP1 to SAMP8, the gain adjustment and linearity correction take a total of 15 minutes, so the adjustment work is divided and performed. For example, the adjustment work is divided into three parts: gain adjustment, linearity correction (1), and linearity correction (2), each of which takes 5 minutes. Therefore, the adjustment work for one SAMP is completed with three substrate transports.

[0045] For example, the adjustment work of MAMP1 to MAMP8 and SAMP1 to SAMP8 is performed by dividing it into 32 (=1×8+3×8) substrate transports as shown in FIG.

[0046] The adjustment work performed during the transportation of the substrate M is not limited to the adjustment work of the DAC amplifier, and may be an adjustment work of other devices constituting the drawing apparatus. For example, parameter adjustment such as stage transportation adjustment may be performed. A plurality of types of adjustment work may be performed during one transportation of the substrate M (one substrate). In this case, it is preferable to determine the execution timing of each work so as to minimize the required time based on the attributes of each adjustment work.

[0047] For example, the attributes include information such as the time required for the work, whether it can be performed in parallel with the substrate movement, the location where it is performed, the order of execution, etc. "Whether it can be performed in parallel with the substrate movement" is an item that indicates whether it can be performed while the substrate is actually being moved by the transport robot. For example, since vibration diagnosis cannot be performed while the substrate is actually being moved by the transport robot, "no" is set for whether it can be performed in parallel.

[0048] The "place of implementation" indicates the location where the substrate M is located when the adjustment work is performed. For example, in the case of an adjustment work to be performed when the substrate M is accommodated in the soaking chamber 350, the "soaking chamber" is set as the place of implementation. In the case where the adjustment work can be performed regardless of where the substrate M is located between the I / F unit 100 and the W chamber 400, the place of implementation is set to "anywhere."

[0049] If there is an order in which multiple adjustment tasks should be performed, the order is set in the "execution order".

[0050] Attribute information for a plurality of adjustment tasks is created in advance and stored in a storage unit (not shown) of the control device 600. The control device 600 refers to the attribute information and determines the execution timing of each adjustment task.

[0051] For example, if the substrate transport from the I / F section 100 to the W chamber 400 is composed of the steps as shown in Table 2 and four types of adjustments 1 to 4 are performed during the transport, the control device 600 refers to attribute information as shown in Table 3 and determines the execution timing of each task so as to minimize the required time.

[0052] [Table 2]

[0053] [Table 3]

[0054] For example, adjustment 4 is performed during a total of 15 minutes, which includes 10 minutes for moving from the I / F unit 100 to the I / O chamber 200 and 5 minutes for moving from the I / O chamber 200 to the soaking chamber 350 .

[0055] Adjustment 1 and Adjustment 3 are performed during the 40-minute soaking in the soaking chamber 350. Thereafter, adjustment 2 is performed using the time spent moving from the soaking chamber 350 to the alignment chamber 320 and from the alignment chamber 320 to the W chamber 400.

[0056] Since it takes 5 minutes to move from the soaking chamber 350 to the alignment chamber 320 and 5 minutes to move from the alignment chamber 320 to the W chamber 400, there is a waiting time of 10 minutes after the substrate M is moved to the W chamber 400 until adjustment 2 is completed. In this example, the time required from when the I / F unit 100 receives the substrate M until the substrate M is transferred to the W chamber 400 and adjustments 1 to 4 are all completed is 75 minutes.

[0057] If adjustments 1 to 4 are grouped together as "pre-adjustments" without considering the attribute information of adjustments 1 to 4 and are performed during soaking of substrate M, the pre-adjustments start when soaking in soaking chamber 350 starts. Since the pre-adjustment takes 75 minutes (=10 minutes + 20 minutes + 30 minutes + 15 minutes), substrate M needs to wait 35 minutes in soaking chamber 350 after soaking ends until pre-adjustment is completed. In this example, the time required from when I / F unit 100 receives substrate M from outside the electron beam drawing apparatus (or from when substrate M is set in I / F unit 100 and waiting) until substrate M is transferred to W chamber 400 and pre-adjustments (adjustments 1 to 4) are completed is 100 minutes.

[0058] By determining the execution timing of each adjustment task in consideration of the attribute information, the time from when the I / F unit 100 receives the substrate M until the drawing process can start can be shortened, thereby improving productivity.

[0059] When the time allocated to the adjustment work of the equipment (equipment constituting the drawing apparatus) during the transportation of one substrate M is shorter than the time required for the adjustment work of this equipment, the adjustment work of this equipment is divided and performed over the transportation of multiple substrates M (multiple substrates).

[0060] The control function of the control device 600 for the adjustment work may be configured with hardware such as an electric circuit, or may be configured with software such as a program that executes these functions. When configured with software, a program that realizes at least some of the functions of the control device 600 may be stored in a non-transitory recording medium 602 such as a CD-ROM, and may be read and executed by a computer having a CPU. The recording medium 602 is not limited to a removable one such as a magnetic disk or an optical disk, and may be a fixed recording medium such as a hard disk device or a memory.

[0061] In the above embodiment, a single-beam lithography apparatus has been described as an electron beam lithography apparatus, but a multi-beam lithography apparatus may also be used.

[0062] The present invention is not limited to the above-described embodiment, and the components can be modified and embodied in the implementation stage without departing from the gist of the invention. In addition, various inventions can be formed by appropriately combining the multiple components disclosed in the above-described embodiment. For example, some components may be deleted from all the components shown in the embodiment. Furthermore, components from different embodiments may be appropriately combined. [Explanation of symbols]

[0063] 100 Interface section 200 Loading / unloading chamber 300 Robot Chamber 400 Lighting Chamber 500 Electron Beam Tube 600 Control device

Claims

1. 1. A method for adjusting a charged particle beam lithography apparatus, comprising the steps of: transporting an undrawn substrate received from outside via an interface unit to a drawing chamber and placing it on a stage; irradiating a charged particle beam onto the substrate on the stage to draw a pattern; and unloading the drawn substrate from the drawing chamber to outside via the interface unit, A method for adjusting a charged particle beam drawing apparatus, comprising performing at least a part of an adjustment operation of equipment of the charged particle beam drawing apparatus while the substrate is being transported between the interface unit and the drawing chamber.

2. 2. The method for adjusting a charged particle beam drawing apparatus according to claim 1, further comprising the step of: performing a plurality of types of adjustment operations while the substrate is being transported.

3. 2. The method for adjusting a charged particle beam drawing apparatus according to claim 1, further comprising determining a timing for performing the adjustment operation based on attribute information that specifies whether the adjustment operation can be performed while the substrate is being transported and a location where the substrate is located when the adjustment operation is performed.

4. 2. The method for adjusting a charged particle beam writing apparatus according to claim 1, wherein the device includes a plurality of DAC (digital-to-analog converter) amplifiers connected to a deflector that deflects the charged particle beam.

5. 2. The method for adjusting a charged particle beam drawing apparatus according to claim 1, wherein, when a substrate transfer is defined as a sequence from when the interface unit receives one substrate to when the substrate is placed on the stage, an adjustment operation of devices constituting the charged particle beam drawing apparatus is divided into a plurality of substrate transfers and executed.

6. an interface unit that receives a substrate from the outside and carries the substrate out to the outside; a drawing chamber in which a stage for placing the substrate thereon is provided, and in which a charged particle beam is irradiated onto the substrate placed on the stage to draw a pattern; a transport unit configured to transport the substrate between the interface unit and the writing chamber; Equipped with A charged particle beam writing apparatus, comprising: a writing chamber that writes the substrate to the writing chamber; and a writing unit that writes the substrate to the writing chamber.

7. a process of transporting an undrawn substrate received from outside via an interface unit of the charged particle beam drawing apparatus to a drawing chamber and placing the substrate on a stage; A process of irradiating a charged particle beam onto a substrate on the stage to write a pattern; a process of unloading the substrate after the drawing from the drawing chamber to the outside via the interface unit; performing at least a part of an adjustment operation of equipment of the charged particle beam drawing apparatus while the substrate is being transported between the interface unit and the drawing chamber; A program for causing a computer of the charged particle beam drawing apparatus to execute the above.

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