JP2013041980A - Charged particle beam drawing device and method for manufacturing product - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an advantageous configuration for a drawing device individually executing blanking to a plurality of charged particle beams.SOLUTION: A charged particle beam drawing device comprises: a data transmission unit 102 for transmitting a blanking command signal synchronously with a synchronizing clock; and a blanking control circuit 105. The data transmission unit transmits,in a prescribed order synchronously with the synchronizing clock, a plurality of pieces of data that are identifiable from each other. The blanking control circuit comprises: a reception unit 130 for receiving a plurality of pieces of data and sequentially reading out the data synchronously with a communication clock having a period shorter than the period of the synchronizing clock; a detection unit for detecting one datum of the plurality of data read out of the reception unit synchronously with the synchronizing clock; and a determination unit 131 for determining a delay time from a prescribed time point based on the synchronizing clock to the time point of the blanking control unit receiving the blanking command signal based on one datum detected by the detection unit, the period of the synchronizing clock, and the period of the communication clock.

Description

  The present invention relates to a charged particle beam drawing apparatus and a method for manufacturing an article using the charged particle beam drawing apparatus.

  In recent years, miniaturization of elements in semiconductor integrated circuits, complicated circuit patterns, and large capacity of pattern data (drawing data) have been advanced. Thus, a drawing apparatus that draws a pattern on a substrate using a charged particle beam such as an electron beam used for manufacturing a semiconductor integrated circuit is required to improve drawing accuracy and drawing throughput. In order to improve the drawing throughput, it is conceivable to increase the number of charged particle beams. However, as the number increases, the pattern data becomes enormous, the data transmission unit that processes and transmits the pattern data becomes complicated, and the processed pattern data is transmitted to the blanking control circuit (blanking control unit). The communication for this also becomes complicated.

  In the electron beam drawing apparatus, a blanking deflector (blanking unit) that controls blanking of the electron beam based on the pattern data transmitted from the data transmitting unit and a position control deflector that controls the irradiation position of the electron beam High-precision synchronization is required between them. The data transmission unit needs to complete transmission of the pattern data before the blanking control circuit operates, and it is desirable that the data transmission unit and the blanking control circuit are also synchronized. In the case of such a system that achieves synchronization at the end, it is generally realized by increasing the communication speed and loosening the synchronization accuracy by preparing a large amount of memory on the receiving side. As a method for detecting a synchronization error in an electron beam drawing apparatus, a method for detecting a synchronization error from a drawing result has been proposed (Patent Document 1).

JP 2009-88202 A

  In the case of a drawing apparatus that performs drawing with a large number of electron beams, the amount of pattern data is enormous, and it is difficult to mount a large amount of memory corresponding to the amount of pattern data in the blanking control circuit on the receiving side is there. Therefore, high synchronization accuracy is also required between the data transmission unit that transmits pattern data and the blanking control circuit that receives pattern data. In order to achieve high synchronization accuracy, when a synchronization error is detected from a drawing result as in Patent Document 1, drawing and development processes on the substrate are necessary, and the number of systems that need to be adjusted is large. It takes time to analyze the results.

  The present invention has been made in view of these problems, and an object of the present invention is to provide an advantageous configuration for a drawing apparatus that individually blanks a plurality of charged particle beams.

  One aspect of the present invention is a drawing apparatus that performs drawing on a substrate with a plurality of charged particle beams, a blanking unit that individually blanks the plurality of charged particle beams, and a blanking in synchronization with a synchronization clock. A data transmission unit that transmits a command signal; and a blanking control unit that receives the blanking command signal transmitted from the data transmission unit and controls the blanking unit. A plurality of unique data that can be distinguished from each other is transmitted in a predetermined order in synchronization with a synchronization clock, and the blanking control unit receives the plurality of unique data transmitted from the data transmission unit and receives the synchronization clock. A receiver that sequentially reads out in synchronization with a communication clock having a cycle shorter than the cycle of the first and second signals read from the receiver in synchronization with the synchronous clock. Based on the detection unit that detects one unique data among the unique data, the one unique data detected by the detection unit, the period of the synchronization clock, and the period of the communication clock. A processing unit for obtaining a delay time from a predetermined time point to a time point when the blanking control unit receives the blanking command signal.

  ADVANTAGE OF THE INVENTION According to this invention, the structure advantageous to the drawing apparatus which performs blanking separately with respect to several charged particle beam can be provided, for example.

It is a figure which shows the structure of an electron beam drawing apparatus. It is a figure explaining the method of calculating the delay time in Example 1. FIG. It is a figure explaining the method of calculating the delay time in Example 2. FIG. It is a figure explaining the method of reducing the delay time in Example 3. FIG.

  Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings. The present invention can be applied to a drawing apparatus that performs drawing on a substrate with a plurality of charged particle beams such as an electron beam and an ion beam. An example applied to a drawing apparatus that performs drawing with a plurality of electron beams will be described. FIG. 1 is a diagram illustrating an example of a multi-electron beam drawing apparatus. The electron gun 211 forms a crossover image 212. The electron beams emitted from the crossover 212 are made parallel by the action of the collimator lens 213 formed of an electromagnetic lens and enter the aperture array 216. The electron beam that has passed through the aperture array 216 is incident on an electrostatic lens 217 that is composed of three electrode plates (three in the drawing are shown integrally) having a circular opening. A blanking aperture 219 is disposed at a position where the electrostatic lens 217 first forms a crossover. A blanking deflector 218 and a blanking aperture 219 (blanking unit) individually turn on / off (blanking) a plurality of electron beams.

  The blanking deflector 218 is controlled by a blanking control circuit (blanking control unit) 105, and the blanking control circuit 105 receives a blanking command signal generated by the data transmission unit 102 that processes and transmits drawing data. Be controlled. The electron beam that has passed through the blanking aperture 219 is imaged by the electrostatic lens 221, and the original image of the crossover 212 is imaged on the substrate 224 such as a wafer or mask or the current detection unit 222. During drawing, the substrate 224 is continuously scanned in the Y direction by the stage 223. An image on the surface of the substrate 224 is deflected in the X direction by the deflector 220 based on the measurement result of the position of the stage 223 by a laser length measuring device or the like. Further, the electron beam is blanked by the blanking deflector 218 based on the blanking command signal so as to be synchronized with them.

  The deflector 220 is controlled by the deflector amplifier 110. The deflection signal generation circuit 109 generates a deflection signal and transmits the deflection signal to the deflector amplifier 110. The collimator lens 213 and the electrostatic lenses 217 and 221 are controlled by the lens control circuits 101 and 106, respectively, and the stage 223 is controlled by the stage control circuit. The controller 100 controls all the drawing operations. The clock distribution unit (distribution unit) 126 distributes the master synchronization clock to the synchronization clock a, the synchronization clock b, and the like according to an operation start command from the controller 100. The clock distribution unit 126 supplies the distributed synchronous clocks a to c to the blanking control circuit 105, the data transmission unit 102, and the deflector amplifier 110, respectively. Hereinafter, a method for calculating a delay time from a predetermined time point of the synchronization clock b related to a synchronization error between the data transmission unit 102 and the blanking control circuit 105 to a time point when the blanking control circuit 105 receives the blanking command signal will be described. To do.

[Example 1]
FIG. 2 illustrates a method for calculating the delay time in the first embodiment. The clock distribution unit 126 starts outputting the synchronous clock a and the synchronous clock b in response to an operation start command from the controller 100. The output synchronization clock a is distributed to the data transmission unit 102 and the synchronization clock b is distributed to the blanking control circuit 105 via different transmission paths. The data transmission unit 102 has a drawing operation mode and a delay detection mode for detecting a delay time. In the drawing operation mode, the data transmission unit 102 transmits drawing data to the blanking control circuit 105 in response to an edge (rising edge) of the synchronous clock a recognized after being delayed from the master synchronous clock. Transmission by the data transmission unit 102 is performed using high-speed serial communication.

  In the delay detection mode, the data transmission unit 102 transmits a group of a plurality of unique data that can be distinguished from each other instead of the drawing data transmitted in the drawing operation mode. In response to a predetermined edge of the synchronous clock a in the delay detection mode, the data transmission unit 102 transmits the unique data group in a predetermined order in synchronization with a communication clock having a period shorter than the period of the synchronous clock a. In the first embodiment, the first edge of the synchronous clock a in the delay detection mode is used as the predetermined edge of the synchronous clock a, but the second and subsequent edges may be used. The unique data group is a data group transmitted during one cycle of the synchronous clock a. In this embodiment, one unique data group is composed of 10 unique data of “A” to “J”. Yes. The data transmission unit 102 starts transmission of a unique data group triggered by a predetermined edge of the synchronous clock a, and the unique data group reaches the blanking control circuit 105 after a delay time corresponding to the length of the transmission path.

The blanking control circuit 105 that receives the unique data group performs the following three operations.
(First Operation) The blanking control circuit 105 operates the synchronous clock counter 133 that increments at the rising edge of the synchronous clock b.
(Second Operation) The blanking control circuit 105 converts the unique data group into, for example, 8-bit parallel data at the communication receiving unit 130 and performs parallel processing in synchronization with the communication clock 135 that is 1/8 of the communication speed of high-speed serial communication. Read data sequentially. The communication receiving unit 130 constitutes a receiving unit that sequentially receives the unique data group transmitted from the data transmitting unit 102 and receives it in synchronization with a communication clock having a cycle shorter than the cycle of the synchronous clock b.
(Third Operation) The blanking control circuit 105 checks the signal level of the synchronous clock b at the edge of the communication clock 135 at the determination unit 131. The determination unit 131 detects a point where the signal level of the synchronous clock b changes from 0 to 1 (later edge) and unique data received at that time. Then, the unique data detected by the determination unit 131 is stored in the unique data storage unit 132, and at the same time, the counting operation of the synchronous clock counter 133 is stopped. In this embodiment, the stored unique data is “G”, which is the seventh in the unique data group. The count value when the synchronous clock counter 133 is stopped is “2”. The determination unit 131, the unique data storage unit 132, and the synchronous clock counter 133 constitute a detection unit that detects the unique data received by the receiving unit at the subsequent edge and the subsequent edge.

It is assumed that the count value when the synchronous clock counter 133 determined by the third operation is stopped is CLK_C, and the order of the stored unique data in the unique data group is Unique_N. The frequency of the synchronous clock b is Sync_F, and the frequency of the communication clock is Data_F. At that time, by substituting these values into Equation 1, a delay time T from when a predetermined edge of the synchronous clock b appears until the reception unit starts receiving the unique data group is determined as a timing calculation unit (processing unit). 134.
T = {CLK_C × (1 / Sync_F)}
-{Unique_N × (1 / Data_F)} (1)

[Example 2]
FIG. 3 illustrates a method for calculating the delay time in the second embodiment. The operation of the clock distribution unit 126 is the same as that of the first embodiment. In the delay detection mode of the data transmission unit 102 according to the second embodiment, a data group including a plurality of data starting with unique data (specific data) 139 is transmitted instead of the unique data group. In this embodiment, the unique data 139 is “A”.

The data transmission unit 102 starts transmission of a data group including the unique data 139 and the random data 140 triggered by the edge of the synchronous clock a. The data group including the unique data 139 and the random data 140 reaches the blanking control circuit 105 after a delay time corresponding to the length of the transmission path. At that time, the blanking control circuit 105 performs four operations.
(First Operation) The blanking control circuit 105 operates the synchronous clock counter 133 that increments at the rising edge of the synchronous clock b.
(Second Operation) The blanking control circuit 105 converts the data group composed of the unique data 139 and the random data 140 transmitted using the high-speed data communication into, for example, 8-bit parallel data at the communication receiving unit 130. . The blanking control circuit 105 calls parallel data in synchronization with a communication clock of 1/8 of the communication speed of high-speed serial communication, and the unique data detection unit 138 detects the unique data 139 included in the data group. Do.
(Third Operation) When the blanking control circuit 105 detects the unique data 139, the blanking control circuit 105 operates the communication clock counter 137 incremented at the edge of the communication clock 135. The communication clock counter 137 constitutes a counting unit that counts communication clocks.
(Fourth Operation) The blanking control circuit 105 confirms the signal level of the synchronous clock b at the edge of the communication clock 135 in the determination unit 131, and the signal level of the synchronous clock b changes from 0 to 1 ( Detect later edge). When a changing point is detected, the count operations of the communication clock counter 137 and the synchronous clock counter 133 are stopped. In this embodiment, the count value when the communication clock counter 137 is stopped is “7”, and the count value when the synchronous clock counter 133 is stopped is “2”.

Assume that the count value when the synchronous clock counter 133 is stopped determined by the fourth operation is CLK_C, and the count value when the communication clock counter 137 is stopped is Data_CLK_N. Further, the frequency of the synchronous clock b is Sync_F, and the frequency of the communication clock 135 is Data_F. At that time, the timing calculation unit (processing unit) 134 can obtain the delay time T by substituting those values into Equation 2.
T = {CLK_C × (1 / Sync_F)}
-{Data_CLK_N × (1 / Data_F)} (2)

  In the first and second embodiments, the time resolution is determined by the frequency of the communication clock 135. In the present embodiment, a communication clock 135 of 1/8 of the communication speed of high-speed serial communication is generated by 8-bit serial-parallel data conversion, and one period of the communication clock 135 has a time resolution. Therefore, for example, in the case of 16-bit serial-parallel data conversion, the communication clock 135 has a frequency that is 1/16 of the communication speed of the high-speed serial communication, and one period of the frequency is the time resolution. By changing the communication speed and the number of bits for serial-parallel data conversion, the required resolution can be obtained. However, it should be noted that the maximum operating frequency of the circuit is limited. In the first and second embodiments, the examples using the rising edges of the synchronous clock a and the synchronous clock b have been described. However, the falling edges may be used.

[Example 3]
A third embodiment in which the delay time calculated by the calculation unit 134 is reduced will be described with reference to FIG. In the third embodiment, a timing adjustment unit 141 is provided in the blanking control circuit 105. Normally, when there is a delay time, the blanking control circuit 105 requires a memory capacity that is at least twice as much as the amount of memory for storing data required for operation within one clock of the synchronous clock b. Therefore, the timing adjusting unit 141 adjusts the timing of receiving drawing data by delaying the synchronous clock b by the delay time T calculated in the first or second embodiment. By doing so, the memory capacity in the blanking control circuit 105 can be made the amount of memory for storing data necessary for operation within one clock of the synchronous clock b.

  In the present embodiment, the timing adjustment unit 141 is provided in the blanking control circuit 105. However, the timing adjustment unit 141 may be provided in the data transmission unit 102 to adjust the timing for transmitting drawing data to the blanking control circuit 105. Good. Further, a timing adjustment unit 141 may be provided in the clock distribution unit 126 to adjust the timing at which the synchronous clock a and the synchronous clock b are output to the data transmission unit 102 and the blanking control circuit 105, respectively.

  The blanking unit includes a plurality of blanking deflectors 218 for blanking a plurality of charged particle beams, respectively. Correspondingly, as shown in FIG. 4, the data transmission unit 102 includes a plurality of data transmission units for transmitting blanking command signals for a plurality of charged particle beams. The blanking control circuit 105 receives a plurality of blanking command signals transmitted by a plurality of data transmission units, and controls a plurality of blanking deflectors 218 based on the received plurality of blanking command signals. A plurality of blanking control units to be included. Therefore, the delay time of each blanking control unit is obtained by any one of the methods described above. Here, if there is a difference in delay time between a plurality of blanking control units, blanking synchronization cannot be achieved among a plurality of blanking deflectors (or blanking deflector groups) corresponding thereto. . This leads to distortion (distortion) of the drawn pattern. Therefore, the non-blanking period is shifted according to the difference in delay time. Specifically, the deflector 220 has a deflection angle larger than that required for drawing, and scans the electron beam blanked by the blanking deflector 218 on the substrate at a constant speed. Here, for example, when the blanking command signal for the part on the substrate that is not irradiated with the electron beam is set to “0”, “0” corresponding to the first blanking period in one deflection period by the deflector 220. What is necessary is just to increase / decrease a number according to the above-mentioned delay time. In other words, if there is a delay, the number of '0's should be reduced accordingly. In other words, in the blanking command signal, the range in which “1” corresponding to the non-blanking period is continuously arranged may be shifted. Therefore, for example, a function of calculating a difference in delay time between a plurality of blanking control units (or a difference between each delay time and a predetermined delay time) is added to the timing calculation unit 134. Then, a blanking command signal adjusted for each blanking control unit may be generated based on the delay time (difference) and the scanning speed of the deflector 220 (the above-mentioned '1' is continuous). You can shift the line-up range). Thereby, more accurate drawing can be performed.

[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 microdevice 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.

Claims (5)

A drawing apparatus for drawing on a substrate with a plurality of charged particle beams,
A blanking section for individually blanking the plurality of charged particle beams;
A data transmission unit that transmits a blanking command signal in synchronization with the synchronous clock;
A blanking control unit that receives the blanking command signal transmitted from the data transmission unit and controls the blanking unit, and
The data transmission unit, in synchronization with the synchronous clock, transmits a plurality of unique data that can be distinguished from each other in a predetermined order,
The blanking control unit
A receiver that receives the plurality of unique data transmitted from the data transmitter and sequentially reads out in synchronization with a communication clock having a cycle shorter than the cycle of the synchronous clock;
A detection unit for detecting one unique data among the plurality of unique data read from the reception unit in synchronization with the synchronization clock;
Based on the one unique data detected by the detection unit, the period of the synchronous clock, and the period of the communication clock, the blanking control unit outputs the blanking command signal from a predetermined time based on the synchronous clock. Including a processing unit that obtains a delay time until reception.
A drawing apparatus characterized by that. A drawing apparatus for drawing on a substrate with a plurality of charged particle beams,
A blanking section for individually blanking the plurality of charged particle beams;
A data transmission unit that transmits a blanking command signal in synchronization with the synchronous clock;
A blanking control unit that receives the blanking command signal transmitted from the data transmission unit and controls the blanking unit, and
The data transmission unit transmits a plurality of data starting with specific data in synchronization with the synchronization clock,
The blanking control unit
A receiver that receives the plurality of data transmitted from the data transmitter and sequentially reads out the data in synchronization with a communication clock having a cycle shorter than the cycle of the synchronous clock;
A counting unit that counts the communication clock from when the specific data is read by the receiving unit until data is read by the receiving unit in synchronization with the synchronous clock;
A delay from a predetermined time based on the synchronous clock to a time when the blanking control unit receives the blanking command signal based on the count value by the counting unit, the cycle of the synchronous clock, and the cycle of the communication clock A processing unit for obtaining time,
A drawing apparatus characterized by that.   Based on the delay time obtained by the processing unit, adjust the timing to output the synchronous clock to the blanking control unit, adjust the timing at which the data transmission unit transmits the blanking command signal, or The drawing apparatus according to claim 1, further comprising an adjustment unit that adjusts a timing at which the blanking control unit receives the blanking command signal.   3. The adjusting device for adjusting the blanking command signal by shifting a signal corresponding to a non-blanking period in the blanking command signal based on the delay time. The drawing apparatus described in 1. Drawing on a substrate using the drawing apparatus according to any one of claims 1 to 4, and
Developing the substrate on which the drawing has been performed in the step;
A method for producing an article comprising:

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