JP2005166928A - Electron beam drawing system - Google Patents

Abstract

An object of the present invention is to provide an electron beam drawing system and an electron beam drawing apparatus capable of calculating the time required for the entire drawing before drawing and obtaining the stage speed accurately.
A storage device stores drawing formation data including drawing data, exposure time, beam irradiation preparation time, stage speed table, and total drawing time. The drawing device stores the drawing formation data stored in the storage device. , And drawing formation is performed, and the drawing formation performed by the drawing apparatus and the creation of the drawing formation data performed by the data conversion preprocessing apparatus are performed asynchronously.
[Selection] Figure 1

Description

  The present invention relates to an electron beam drawing system and an electron beam drawing apparatus.

  In a semiconductor integrated circuit manufacturing process, a wafer or mask is drawn using a charged electron beam drawing apparatus. As the LSI pattern becomes finer, drawing with a higher resolution electron beam is performed in order to draw a fine pattern.

  Drawing is performed in units of stripe drawing areas (also referred to as frames). The stripe drawing area unit is an area that exists along the moving direction of the stage and has the same width as the deflection width of the deflector. At the time of drawing, the electron beam drawing apparatus reads the drawing data and converts it into shot data of a size that can be drawn unique to the electron beam drawing apparatus. Then, drawing is performed while continuously moving the stage along the stripe drawing area unit.

  The stage must be moved so that it can follow the drawing. Drawing can be followed by moving the stage at a constant slow speed. However, this will affect the throughput of the electron beam drawing apparatus. Therefore, it is necessary to change the stage moving speed according to the density of the drawing pattern.

  In the stage moving speed calculation method disclosed in Japanese Patent Laid-Open No. 2002-33265 (Patent Document 1) (Prior Art 1), empty drawing (drawing) is performed for each small region (drawing divided region) obtained by dividing the stripe drawing region unit into an arbitrary width. (Drawing simulation performed by sending data to the apparatus) to obtain a distribution of shot patterns that are irradiation of each electron beam. Compare the settling time required for beam forming and settling time for shot positioning for each shot pattern, and set the longer time as the beam irradiation preparation time for each shot, and the sum of the drawing time from the sum of the beam irradiation preparation time in the small area Then, the stage moving speed is calculated by dividing the small area width (length) by the total drawing time. The slowest speed is calculated in the small area in the stripe drawing area unit, and the stripe area is stage-moved at the calculated speed.

  By the way, when drawing is performed using an electron beam with high resolution, the electrons are reflected inside the wafer, and the resist is exposed again. For this reason, the phenomenon that the space | interval of the part which adjoins a big figure will be drawn narrow occurs. That is, the drawing interval becomes narrower when the amount of drawing drawing data is high than when the amount of drawing drawing operation data is low. This phenomenon is called proximity effect. This re-exposure is equivalent to thinning again over a wider area. Therefore, overexposure occurs and the interval is drawn narrowly. This proximity effect is shown in Japanese Patent No. 2862532 (Patent Document 2) (Conventional Example 2).

Patent Document 2 describes that proximity effect correction is performed in order to draw a desired pattern in consideration of the proximity effect. According to the description, the figure pattern is divided into a plurality of partial areas before drawing by the electron beam drawing apparatus, and empty drawing for calculating the drawing area (exposure amount map) of each partial area is performed. The exposure time considering the proximity effect can be calculated in a short time by empty drawing, and the proximity effect can be corrected in real time.

  The electron beam drawing apparatus disclosed in Patent Document 1 stores design pattern data (drawing data) such as wafer chips and masks in a storage device, reads the drawing data in units of stripe regions, pattern memory, and drawing graphic data. In the decoder and the drawing position data decoder, the drawing tool of the drawing apparatus is changed into drawing operation data that can be drawn and passed to the drawing tool.

JP 2002-33265 A

Japanese Patent No. 2862532

  In the above conventional example, the drawing operation data remade for each stripe area unit is passed to the drawing tool (drawing apparatus) side. The (drawing apparatus) side has always been linked to each other.

  Since the drawing tool (drawing apparatus) side and the side for recreating the drawing operation data are configured to cooperate with each other, they cannot operate independently without being restrained. For this reason, the time required for drawing a chip or a mask cannot be known in advance, and it is difficult to plan and manage the entire production time.

  Further, the drawing pattern of the wafer chip, mask, and the like is complicated, and drawing is not performed at the stage speed corresponding to the drawing figure, although the drawing figure is different for each unit of the stripe region.

  SUMMARY OF THE INVENTION An object of the present invention is to provide an electron beam drawing system and an electron beam drawing apparatus that can solve the above-described problems, can calculate the entire drawing time before drawing, and can accurately determine the stage speed. To do.

  The present invention includes a drawing device, a data conversion preprocessing device, and a storage device, and the data conversion preprocessing device has a size or a figure that allows the drawing device to draw design data such as a sample wafer or chip. Figure decomposition unit to convert to drawing data, exposure time calculation unit to calculate exposure time from drawing data, beam irradiation preparation time calculation to calculate beam irradiation preparation time from settling time required for electron beam shaping and electron beam deflection And a stage speed calculation unit that calculates a stage speed table during drawing and a total drawing time from drawing data, exposure time, and beam irradiation preparation time, and a storage device includes drawing data, exposure time, beam irradiation preparation time, The drawing speed data including the stage speed table and the total drawing time is stored, and the drawing device reads the drawing data stored in the storage device to form the drawing. And generation of the drawing forming data drawing forming a data conversion pretreatment apparatus drawing apparatus performs performed is characterized by being performed asynchronously.

  According to the present invention, it is possible to know in advance the time required for drawing before operating the drawing apparatus, and overall plan management of production time can be established.

  In addition, since an accurate stage speed corresponding to the drawing figure can be obtained, it is possible to know a more accurate time required for drawing.

  An example according to the embodiment of the present invention will be described below with reference to the drawings.

  FIG. 1 shows a schematic configuration of an electron beam drawing system / electron beam drawing apparatus. The electron beam drawing system includes a data conversion pre-processing device 110, a storage device 120, and a drawing device 130. The host computer 1000 controls the data conversion preprocessing device 110, the storage device 120, and the drawing device 130. The data in the recording unit 910 is taken into the data conversion pre-processing device 110 under the instruction of the host computer 1000.

  The data conversion pre-processing apparatus 110 recreates design data such as wafer chips and masks into drawing formation data that can be drawn by the drawing apparatus 130. This drawing formation data includes drawing data and exposure time calculated by dividing the design data into figures that can be drawn by the drawing device 130, and calculates the stage speed table using these values and beam irradiation preparation time. Also included.

  The storage device 120 stores the drawing data of the entire drawing area calculated by the data conversion preprocessing device 110, the exposure time, and the stage speed table. The drawing device 130 reads data from the storage device 120, performs follow-up control, stage control, and exposure control, and performs drawing. The data conversion pre-processing device 110 and the drawing device 130 perform processing asynchronously. That is, the data conversion pre-processing device 110 and the drawing device 130 operate independently without being constrained to each other. The drawing device 130 arbitrarily reads the drawing formation data stored in the storage device 120, and the drawing operation is performed.

  Since the drawing formation data recreated by the data conversion pre-processing apparatus 110 can be stored in the storage device, the data conversion pre-processing apparatus can create drawing formation data regardless of the operation of the drawing apparatus. Further, the drawing apparatus can arbitrarily read the drawing formation data in the storage device and perform drawing irrespective of the operation of the data conversion pre-processing apparatus.

  FIG. 2 shows a configuration diagram of the data conversion pre-processing device 110. The data conversion pre-processing apparatus 110 includes a graphic decomposition unit 111, an exposure time calculation unit 112, a beam irradiation preparation time calculation unit 113, and a stage speed calculation unit 114.

  The graphic decomposition unit 111 reads design data such as a wafer chip and mask including LSI data from the recording unit 910 and converts the design data into a graphic having a size and shape that can be drawn by the drawing apparatus 130.

  The exposure time calculation unit 112 receives the drawing data converted by the figure decomposition unit 111, performs proximity effect correction and fog correction in consideration of the area of the drawing pattern to be drawn, and calculates the exposure time of each figure. In the proximity effect, the drawing interval is narrower when the area of the drawing pattern is large than when the area of the drawing pattern is small, and proximity effect correction and fog correction corresponding to the area of the drawing pattern are required. It is.

  The beam irradiation preparation time calculation unit 113 calculates the time taken from the time when the previous graphic is shot until the next graphic can be shot. This beam irradiation preparation time is calculated for each figure. The stage speed calculation unit 114 receives drawing data from the graphic decomposition unit 111, exposure time for drawing from the exposure time calculation unit 112, and beam irradiation preparation time from the beam irradiation preparation time calculation unit 113. As the beam irradiation preparation time, the longer settling time required for electron beam shaping or electron beam deflection is used.

  A stage speed table is calculated for each stripe area from the drawing data, the exposure time of the drawing pattern, and the beam irradiation preparation time.

  Further, the total drawing time for one chip / one mask is calculated from the following equation.

In the storage device 120, the drawing data created by the graphic decomposition unit 111, the exposure time calculated by the exposure time control unit 112, the stage speed table calculated by the stage speed calculation unit 114, and the total drawing time are written. Even when the data read by the graphic decomposition unit 111 is CAD data or other converted data, the data conversion pre-processing device 110 can be similarly configured.

  In this way, the time required to draw one chip / one mask can be created by the data conversion pre-processing device before the drawing apparatus is operated, so that the host computer 1000 can be based on the drawing time for one chip / one mask. Thus, by summing up the entire production, production time plan management can be easily established.

  FIG. 3 shows a sequence of the data conversion preprocessing apparatus 110.

  First, LSI data is read (step 20). Next, the figure is decomposed into a size and shape that can be shot by the drawing apparatus with respect to the read LSI data (step 30). The beam irradiation preparation time after finishing the shot of the figure is obtained for all the figures (step 41).

  The beam irradiation preparation time is calculated from the settling time required for electron beam shaping and electron beam deflection. The settling time is the time until the shaping voltage or deflection voltage of the electron beam is stabilized, and the longer one is set as the beam irradiation preparation time.

  Here, the calculation of the exposure time (step 42) will be described along the sequence of FIG.

  First, the stripe drawing area unit is divided into divided drawing areas that are divided so as to cross the stage moving direction, drawing data occupying each divided drawing area is calculated, and an exposure amount map is created (step 422). Next, proximity effect correction and fog correction are performed, and exposure times of all figures are calculated (step 423).

  Here, the stage speed calculation table (step 50) of FIG. 3 is described along the sequence of FIG.

  The time for drawing each figure is determined from the beam irradiation preparation time and exposure time of each figure (step 502). An optimal stage speed table is calculated from the drawing time and drawing position of each figure (step 503).

  Through these steps, the stage speed table, exposure time, and drawing data shown in FIG. 3 are written in the storage device 120 in units of stripe drawing areas (step 60).

  FIG. 6 shows a configuration diagram of the drawing apparatus 130. The drawing apparatus 130 includes a data correction unit 131, a follow-up control unit 132, a length meter 133, a stage speed control unit 134, an exposure control unit 135, and an exposure unit 136. The data correction unit 131 reads the drawing data, the exposure time, and the stage speed table from the storage device 120, corrects the exposure time and the stage speed table with parameters unique to the apparatus, and changes the exposure time and the stage speed table suitable for the apparatus. This is a process for reflecting data unique to the apparatus, such as a beam current. The follow-up control unit 132 receives the drawing pattern position data included in the drawing data from the data correction unit 131, receives the current stage position coordinates from the length meter 133, and obtains the beam deflection amount in consideration of the stage position. The length meter 133 calculates stage position coordinates from the stage of the exposure unit 136. The stage speed calculation unit 134 receives the current stage position from the length meter 133 and the drawing data and the stage speed table from the data correction unit, calculates the target stage speed, and controls the stage speed. The exposure control unit 135 controls the exposure unit 136 and the exposure unit 136 performs drawing.

  FIG. 7 shows a sequence diagram of the drawing apparatus 130. Drawing is started (step 81). A stage speed table for one stripe is read from the storage device 120 (step 82). The stage speed table suitable for the drawing apparatus 130 is corrected using the apparatus parameters (step 83). The exposure time and drawing data are read from the storage device 120 in graphic units (step 84). The exposure time suitable for the drawing apparatus 130 is corrected using the apparatus parameters (step 85). A target stage speed is obtained from the read stage speed table for one stripe and the current stage position coordinates (step 86). A beam deflection amount is obtained from the current position coordinates of the stage and the position coordinates of the drawing pattern included in the drawing data (step 87). Drawing is performed by controlling the electron beam and the stage (step 88). If a drawing figure remains in the stripe data, the process jumps to step 84. If no drawing figure remains in the stripe data, the process proceeds to step 90 (step 89). If stripe data remains in the storage device, the process jumps to step 82. If no stripe data remains in the storage device 120, the process proceeds to step 91 (step 90). Drawing ends (step 91).

  FIG. 8 shows another configuration of the pattern drawing system. The data conversion preprocessing apparatus 110 performs figure decomposition on the entire drawing area, calculates the exposure time and beam irradiation preparation time, and calculates the stage speed using the calculated values. The storage device 120 stores drawing data, exposure time, and stage speed of the entire drawing area calculated by the data conversion preprocessing device 110. The plurality of drawing apparatuses 130 read data from the storage device 120, perform absolute calibration, follow-up control, stage control, and exposure control, and perform drawing. The data conversion pre-processing device 110 and each drawing device 130 perform processing asynchronously.

  In this configuration, by storing the data conversion pre-processing device 110 in the storage device 120, a plurality of drawing devices 130 can be operated, and an overall configuration of an electron beam drawing system having a plurality of drawing devices. Can be made compact.

The block diagram which concerns on the Example of this invention and shows the structure of the electron beam drawing system which manufactures a semiconductor. The block diagram which concerns on the Example of this invention and shows the structure of the data pre-processing apparatus in FIG. The figure which concerns on the Example of this invention and shows the sequence of the data pre-processing apparatus in FIG. The figure which concerns on the Example of this invention and shows the sequence in exposure time calculation in FIG. The figure which concerns on the Example of this invention and shows the sequence in the stage speed table calculation in FIG. The block diagram which concerns on the Example of this invention and shows the structure of the drawing apparatus in FIG. The figure which concerns on the Example of this invention and shows the sequence of the drawing apparatus in FIG. The block diagram which concerns on the other Example of this invention, and shows the structure of the electron beam drawing system which manufactures a semiconductor.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 110 ... Data conversion pre-processing apparatus, 120 ... Memory | storage device, 130 ... Drawing apparatus, 111 ... Graphic decomposition | disassembly part, 112 ... Exposure time calculation part, 113 ... Beam irradiation preparation time calculation part, 114 ... Stage speed calculation part.

Claims (5)

A drawing device, a data conversion pre-processing device, and a storage device;
The drawing apparatus includes an exposure unit that performs drawing by irradiating a sample with an electron beam, and a stage speed control unit that controls a moving speed of a stage when the exposure unit performs drawing,
The data conversion pre-processing device includes a figure decomposition unit that changes design data of a sample into drawing data of a figure that can be drawn by the drawing device, an exposure time calculation unit that calculates an exposure time from the drawing data, A beam irradiation preparation time calculation unit for calculating a beam irradiation preparation time from a settling time required for electron beam shaping and electron beam deflection, and the stage during drawing of the drawing apparatus from the drawing data, exposure time, and beam irradiation preparation time A stage speed table for controlling the moving speed of the stage and a stage speed calculator for calculating the total drawing time,
The storage device stores drawing formation data including the drawing data, the exposure time, the beam irradiation preparation time, the stage speed table, and the total drawing time.
The drawing device reads the drawing formation data stored in the storage device, performs drawing by irradiating the drawing device with an electron beam, and the calculation performed by the drawing and the data conversion preprocessing device. An electron beam drawing system characterized by being performed asynchronously. The electron beam drawing system according to claim 1,
A proximity effect correction is performed by correcting the exposure time according to an area of a drawing pattern based on the drawing data. The electron beam drawing system according to claim 1,
2. The electron beam drawing system according to claim 1, wherein the drawing formation data is calculated for each stripe area scanned in the moving direction of the stage. The electron beam drawing system according to claim 1,
2. The electron beam drawing system according to claim 1, wherein the drawing apparatus includes a data correction unit that corrects the drawing formation data read from the storage device with parameters unique to each drawing apparatus. The electron beam drawing system according to claim 1,
An electron beam drawing system comprising a plurality of drawing devices that receive the drawing formation data from the storage device.

Images