JP5731257B2 - Charged particle beam drawing apparatus and charged particle beam drawing method - Google Patents

Description

  The present invention relates to a charged particle beam drawing apparatus and a charged particle beam drawing method, and more particularly, to a technique for correcting pattern dimension variations caused by a mask process in electron beam drawing.

  Lithography technology, which is responsible for the progress of miniaturization of semiconductor devices, is an extremely important process for generating a pattern among semiconductor manufacturing processes. In recent years, with the high integration of LSI, circuit line widths required for semiconductor devices have been reduced year by year. In order to form a desired circuit pattern on these semiconductor devices, a highly accurate original pattern (also referred to as a reticle or a mask) is required. Here, the electron beam (electron beam) drawing technique has an essentially excellent resolution, and is used for producing a high-precision original pattern.

FIG. 18 is a conceptual diagram for explaining the operation of a conventional variable shaping type electron beam drawing apparatus.
The variable shaped electron beam (EB) drawing apparatus operates as follows. In the first aperture 410, a rectangular opening for forming the electron beam 330, for example, a rectangular opening 411 is formed. Further, the second aperture 420 is formed with a variable shaping opening 421 for shaping the electron beam 330 having passed through the opening 411 of the first aperture 410 into a desired rectangular shape. The electron beam 330 irradiated from the charged particle source 430 and passed through the opening 411 of the first aperture 410 is deflected by the deflector, passes through a part of the variable shaping opening 421 of the second aperture 420, and passes through a predetermined range. The sample 340 mounted on a stage that continuously moves in one direction (for example, the X direction) is irradiated. That is, the drawing area of the sample 340 mounted on the stage in which the rectangular shape that can pass through both the opening 411 of the first aperture 410 and the variable shaping opening 421 of the second aperture 420 is continuously moved in the X direction. Drawn on. A method of creating an arbitrary shape by passing both the opening 411 of the first aperture 410 and the variable shaping opening 421 of the second aperture 420 is referred to as a variable shaping method (VSB method).

  In electron beam drawing, line width uniformity within a sample surface, for example, a mask surface, with higher accuracy is required. Here, in such electron beam drawing, when a circuit pattern is drawn by irradiating a resist-coated mask with an electron beam, the electron beam passes through the resist layer and reaches the layer below it, and then reappears on the resist layer again. A phenomenon called a proximity effect due to incident backscattering occurs. Thereby, at the time of drawing, the dimension fluctuation | variation which will be drawn in the dimension shifted | deviated from the desired dimension will arise. However, in addition to the proximity effect, it has been found that dimensional variations due to processes related to mask manufacturing occur. A so-called phenomenon called a mask process effect occurs. For this reason, conventionally, in order to correct the mask process effect, the mask process effect is modeled by a model formula having a very large calculation amount to obtain a correction amount (see, for example, Non-Patent Document 1). The calculation time in such a model requires a long time, and the mask process correction (MPC) software is generally expensive.

  In general, when a desired pattern is transferred to a silicon wafer, the pattern is not directly formed on the mask, but proximity effect correction (OPC) for correcting a dimensional variation due to the optical proximity effect at the time of transfer. ). In addition, on the user side that manufactures semiconductor devices, the organization is generally divided into a wafer manufacturing department and a mask manufacturing department. The OPC described above is performed by the wafer manufacturing department, and the MPC mask parameters are obtained by the mask manufacturing department. It was. This difference in organization has also been an obstacle to applying MPC to the production of semiconductor devices. On the other hand, in the case of a mask shop where another company (another user) manufactures the mask, the wafer manufacturing department is on the customer side of the mask shop, so that there is a problem that MPC becomes more difficult including information distribution. It was.

  FIG. 19 is a diagram illustrating an example of a design pattern, a pattern after OPC, and a pattern after OPC and MPC. The finished dimension of the mask is a pattern after OPC, whereas the dimension when the pattern is drawn on the mask is the pattern after OPC and MPC, so that the input image and the finished image are different. The manufactured mask is inspected for the presence or absence of pattern defects by a mask inspection apparatus. However, since the input image and the finished image are different, there is a problem that the determination of the presence or absence of defects becomes complicated. For example, when comparing the pattern image after OPC and MPC with the finished image of the mask, image conversion or the like is required for the comparison. In addition, when comparing a simulation image of a pattern on a wafer manufactured from a mask after OPC and MPC with a pattern image on an actual wafer, a simulation or the like is required for the comparison. Further, when inspecting using the pattern data of the finished pattern of the mask, it is necessary to prepare the pattern data after the OPC and MPC for mask drawing and the pattern data of the finished pattern of the mask. As described above, there has been a problem that the determination of whether or not the test is acceptable becomes complicated when the manufactured mask is inspected.

  Furthermore, the pattern data to be input to the drawing apparatus is a plurality of rectangles and triangles depending on the drawing process performed by the drawing apparatus or the drawing apparatus after the MPC and before being input to the drawing apparatus. In this way, drawing data in which the pattern data of each figure is defined is generated (fracture processing). Since the MPC described above depends on the drawing apparatus and process, there is a problem that it becomes difficult to use the generated drawing data in other drawing apparatuses.

G. Chen et al, "Model Based Shot Range Mask Process Correction", Prec. of SPIE Vol. 7028 70280G-1

  As described above, the conventional MPC has a problem that it takes a long time to calculate, and the mask process correction (MPC) software is generally expensive. Furthermore, since the organization differs between the department that performs OPC and the department that calculates the parameters of MPC, it has also become an impediment to applying MPC to the production of semiconductor devices. Further, in the case of a mask shop, since the wafer manufacturing department is on the customer side of the mask shop, there has been a problem that MPC becomes more difficult including information distribution. Furthermore, the drawing data generated by the conventional MPC method has a problem that it becomes difficult to use it with other drawing apparatuses.

  Accordingly, an object of the present invention is to provide an apparatus and a method that can overcome the above-described problems and can perform dimensional variation correction more easily.

A charged particle beam drawing apparatus according to one embodiment of the present invention includes:
A storage unit for storing each graphic data in which a coordinate of a reference position, a graphic size in the x direction, a graphic size in the y direction, and a correction direction are defined for each graphic forming a pattern in which a plurality of graphics are connected;
A width dimension calculation unit that calculates the width dimension of the figure in the correction direction indicated by the figure data;
An area density calculation unit that calculates a pattern density of a mesh area in which a figure is arranged among a plurality of mesh areas virtually divided by a predetermined size,
A correction coefficient calculating unit for calculating by using the function obtained by experiment a correction coefficient for correcting the width for inputting the pattern density and the width as a parameter,
A first dose calculator for calculating a first dose of a charged particle beam for drawing a figure;
A second dose calculation unit for calculating a second dose obtained by multiplying the first dose by the correction coefficient;
A drawing unit for drawing a figure on a sample using a charged particle beam of a second dose;
It is provided with.

A charged particle beam drawing apparatus according to another aspect of the present invention is provided.
Each figure data in which coordinates of a reference position, a figure size in the x direction, a figure size in the y direction, and a width dimension of the figure in the correction direction are defined is stored for each figure constituting a pattern obtained by connecting a plurality of figures. A storage unit;
An area density calculation unit that calculates a pattern density of a mesh area in which a figure is arranged among a plurality of mesh areas virtually divided by a predetermined size,
A correction coefficient calculating unit for calculating by using the function obtained by experiment a correction coefficient for correcting the width for inputting the pattern density and the width as a parameter,
A first dose calculator for calculating a first dose of a charged particle beam for drawing a figure;
A second dose calculator for calculating a second dose obtained by multiplying the first dose by a correction coefficient;
A drawing unit for drawing a figure on a sample using a charged particle beam of a second dose;
It is provided with.

A charged particle beam drawing apparatus according to another aspect of the present invention is provided.
A storage unit for storing each graphic data in which a coordinate of a reference position, a graphic size in the x direction, a graphic size in the y direction, and a correction direction are defined for each graphic forming a pattern in which a plurality of graphics are connected;
A width dimension calculation unit for calculating the width dimension of the figure in the correction direction indicated by the figure data;
An area density calculation unit that calculates a pattern density of a mesh area in which a figure is arranged among a plurality of mesh areas virtually divided by a predetermined size,
A correction amount calculator for calculating by inputting the pattern density and the width by using a function obtained by experiment a correction amount for correcting the width as a parameter,
For a figure, a resize processing unit that resizes the width dimension with a correction amount;
A drawing unit that draws a resized figure on the sample using a charged particle beam;
It is provided with.

A charged particle beam drawing apparatus according to another aspect of the present invention is provided.
Each figure data in which coordinates of a reference position, a figure size in the x direction, a figure size in the y direction, and a width dimension of the figure in the correction direction are defined is stored for each figure constituting a pattern obtained by connecting a plurality of figures. A storage unit;
An area density calculation unit that calculates a pattern density of a mesh area in which a figure is arranged among a plurality of mesh areas virtually divided by a predetermined size,
A correction amount calculator for calculating by inputting the pattern density and the width by using a function obtained by experiment a correction amount for correcting the width as a parameter,
For a figure, a resize processing unit that resizes the width dimension with a correction amount;
A drawing unit that draws a resized figure on the sample using a charged particle beam;
It is provided with.

The charged particle beam drawing method of one embodiment of the present invention includes:
Each figure is stored from a storage device that stores figure data in which the coordinates of the reference position, the figure size in the x direction, the figure size in the y direction, and the correction direction are defined for each figure constituting a pattern in which a plurality of figures are connected. Reading the data and calculating the width dimension of the figure in the correction direction indicated by the figure data;
A step of calculating a pattern density of a mesh region in which a figure is arranged among a plurality of mesh regions virtually divided by a predetermined size in a drawing region;
A step of calculating a correction coefficient for correcting the width dimension by inputting the width dimension and the pattern density as parameters using a function obtained in advance by experiment ;
Calculating a first dose of a charged particle beam for drawing a figure;
Calculating a second dose by multiplying the first dose by a correction factor;
Drawing a figure on a sample using a charged particle beam of a second dose;
It is provided with.

  According to one embodiment of the present invention, dimensional variation correction can be performed more easily. Furthermore, correction calculation can be performed in the drawing apparatus. Therefore, it is possible to avoid the difficulty of applying correction due to the difference in the manufacturing department on the user side. As a result, highly accurate drawing can be performed.

1 is a conceptual diagram illustrating a configuration of a drawing apparatus according to Embodiment 1. FIG. 4 is an example of a graph showing a change in pattern dimensions with and without MPC correction in the first embodiment. FIG. 4 is a flowchart showing main steps of the drawing method according to Embodiment 1. FIG. 3 is a diagram showing an example of a test pattern in the first embodiment. 3 is an example of a graph showing a correlation among a line width dimension, a pattern density, and a correction dose amount in the first embodiment. 10 is another example of a graph showing the correlation among the line width dimension, the pattern density, and the correction dose amount in the first embodiment. 6 is a diagram showing an example of a mesh region in Embodiment 1. FIG. FIG. 3 is a diagram illustrating an example of a plurality of figures constituting a pattern in the first embodiment. 6 is a conceptual diagram illustrating a configuration of a drawing apparatus according to Embodiment 2. FIG. FIG. 10 is a flowchart showing main steps of a drawing method according to Embodiment 2. It is a figure which shows an example of the some figure which comprises the pattern in Embodiment 2. FIG. FIG. 10 is a conceptual diagram illustrating a configuration of a drawing apparatus according to a third embodiment. FIG. 10 is a flowchart showing main steps of a drawing method according to Embodiment 3. FIG. 10 is a diagram showing an example of a test pattern in the third embodiment. 3 is an example of a graph showing a correlation between a line width dimension, a pattern density, and a resizing rate in the first embodiment. FIG. 10 is a conceptual diagram illustrating a configuration of a drawing apparatus according to a fourth embodiment. FIG. 10 is a flowchart showing main steps of a drawing method according to Embodiment 4. It is a conceptual diagram for demonstrating operation | movement of the conventional variable shaping type | mold electron beam drawing apparatus. It is a figure which shows an example of the design pattern, the pattern after OPC, and the pattern after OPC and MPC.

  Hereinafter, in the embodiment, a configuration using an electron beam will be described as an example of a charged particle beam. However, the charged particle beam is not limited to an electron beam, and a beam using charged particles such as an ion beam may be used. Further, a variable shaping type drawing apparatus will be described as an example of the charged particle beam apparatus.

Embodiment 1 FIG.
FIG. 1 is a conceptual diagram illustrating a configuration of a drawing apparatus according to the first embodiment. In FIG. 1, the drawing apparatus 100 includes a drawing unit 150 and a control unit 160. The drawing apparatus 100 is an example of a charged particle beam drawing apparatus. In particular, it is an example of a variable shaping type (VSB type) drawing apparatus. The drawing unit 150 includes an electron column 102 and a drawing chamber 103. In the electron column 102, there are an electron gun 201, an illumination lens 202, a blanking deflector (blanker) 212, a blanking aperture 214, a first shaping aperture 203, a projection lens 204, a deflector 205, and a second shaping aperture. 206, an objective lens 207, a main deflector 208, and a sub deflector 209 are disposed. An XY stage 105 that can move at least in the XY direction is disposed in the drawing chamber 103. On the XY stage 105, a sample 101 to be drawn is arranged. The sample 101 includes an exposure mask for manufacturing a semiconductor device. Masks include mask blanks. A resist is applied on the sample 101.

  The control unit 160 includes a control computer 110, a memory 112, a deflection control circuit 120, and storage devices 140, 142, 144, and 148 such as a magnetic disk device. The control computer 110, the memory 112, the deflection control circuit 120, and the storage devices 140, 142, 144, and 148 are connected to each other via a bus (not shown).

  In the control computer 110, a shot division unit 50, a shot figure data generation unit 52, an irradiation amount calculation unit 54, a pattern density calculation unit 60, and a dose correction coefficient calculation unit 64 are arranged. Each function such as the shot division unit 50, the shot figure data generation unit 52, the dose calculation unit 54, the pattern density calculation unit 60, and the dose correction coefficient calculation unit 64 may be configured by software such as a program. Alternatively, it may be configured by hardware such as an electronic circuit. Alternatively, a combination thereof may be used. The input data necessary for the control computer 110 or the calculated result is stored in the memory 112 each time.

  In the deflection control circuit 120, an irradiation amount correction unit 70 (second irradiation amount calculation unit) and a deflection amount calculation unit 72 are arranged. Each function such as the irradiation amount correction unit 70 and the deflection amount calculation unit 72 may be configured by software such as a program. Alternatively, it may be configured by hardware such as an electronic circuit. Alternatively, a combination thereof may be used. Input data necessary for the deflection control circuit 120 or the calculated result is stored in a memory (not shown) each time.

  The storage device 140 stores a graphic code, coordinates of a reference position, a graphic size in the x direction, a graphic size in the y direction, and a line width dimension w of the graphic in the correction direction for each graphic forming a pattern in which a plurality of graphics are connected. Drawing data based on each graphic data defined as "" is input from the outside and stored. Here, as described above, it goes without saying that the pattern after OPC is subjected to fracture processing, and the pattern is decomposed into a plurality of figures.

  Here, FIG. 1 shows a configuration necessary for explaining the first embodiment. The drawing apparatus 100 may normally have other necessary configurations. For example, the main and sub two-stage main deflector 208 and sub-deflector 209 are used here, but one stage or three or more stages of deflectors may be used. Further, the deflection control circuit 130 is connected to the blanking deflector 212, the deflector 205, the main deflector 208, and the sub-deflector 209 via each DAC (not shown).

FIG. 2 is an example of a graph showing how the pattern dimension fluctuates with and without MPC correction in the first embodiment. In FIG. 2, the vertical axis represents the amount of dimensional variation (dimensional error), and the horizontal axis represents the line width dimension of the pattern. When proximity effect correction and MPC (mask process correction) are performed, the dimensional variation amount can be corrected to almost zero regardless of the pattern density D _ML (pattern area density) as shown in FIG. Yes. On the other hand, even if proximity effect correction is performed, if MPC is not performed, as shown in FIG. 2, when the line width dimension of the pattern becomes thinner than 400 nm, it depends on the pattern density D _ML . A dimensional error will occur. In particular, at 200 nm or less, the amount of dimensional variation varies greatly depending on the pattern density _DML . Thus, it has been found that MPC is important to depend on the line width dimension w and the pattern density D _ML .

  FIG. 3 is a flowchart showing main steps of the drawing method according to the first embodiment. In FIG. 3, the drawing method according to the first embodiment includes a shot division step (S102), a shot figure data generation step (S104), a pattern density calculation step (S110), a dose correction coefficient calculation step (S114), A series of steps of an irradiation amount calculation step (S114), an irradiation amount correction step (S120), a deflection amount calculation step (S122), and a drawing step (S124) are performed.

In the first embodiment, a simple model is set using the figure width dimension w and the pattern density D _ML as parameters. In the simple model, the dose correction coefficient f is obtained by changing the dose ratio C (corrected dose amount), the width dimension w, and the pattern density _DML . The dose correction coefficient f is defined so as to satisfy the following relational expression (1).
(1) C = f (w, D _ML )

FIG. 4 is a diagram illustrating an example of a test pattern in the first embodiment. In FIG. 4, the evaluation ratio 10 of the line width dimension w1 of the pattern densities D _ML = D _ML1 , D _ML2 , D _ML3 is the dose ratio of the original dose amount (the dose amount after the proximity effect correction by the electron beam is preferable). Shake C and draw on a test substrate having a light-shielding film coated with a resist. For example, D _ML1 ≈ 0 (substantially 0%), D _ML2 = 0.5 (50%), D _ML3 = 1 (100%), and at each pattern density D _ML , the dose ratio C = 0.98 (98 %), 1 (100%), and 1.02 (102%). Then, the dimension of the light shielding film pattern obtained by developing and etching the drawn test substrate is measured. Then, in addition to w = w1, w = w2, w3... And the line width dimension w are changed, and similarly, D _ML1 ≈0 (substantially 0%), D _ML2 = 0.5 (50%), With D _ML3 = 1 (100%), and with each pattern density D _ML , the evaluation pattern 10 with a dose ratio of C = 0.98 (98%), 1 (100%), 1.02 (102%) Draw. Then, the dimension of the light-shielding film pattern obtained by developing and etching the drawn test substrate is measured.

FIG. 5 is an example of a graph showing the correlation among the line width dimension, the pattern density, and the correction dose amount in the first embodiment. In FIG. 5, as described above, pattern dimensional variations caused by the mask process obtained as a result of experiments with the dose ratio C (corrected dose amount), the width dimension w, and the pattern density D _ML being variable are shown. An example of a set of a corrected dose ratio C (corrected dose amount), a width dimension w, and a pattern density _DML is shown.

FIG. 6 is another example of the graph showing the correlation among the line width dimension, the pattern density, and the correction dose amount in the first embodiment. In FIG. 6, as described above, the pattern dimensional variation due to the mask process obtained as a result of the experiment with the dose ratio C (corrected dose amount), the width dimension w, and the pattern density D _ML being variable is shown. A plurality of sets of corrected dose ratio C (corrected dose amount), width dimension w, and pattern density D _ML are shown. Then, a function of the dose correction coefficient f (w, D _ML ) satisfying the formula (1) is calculated by fitting using the plurality of sets. The function f (w, D _ML ) based on the above experiment is performed as a pre-process before drawing starts. Then, the parameters of the obtained function f (w, D _ML ) are input from the outside to the storage device 148 and stored. Thus, _w, by entering in the drawing apparatus _{D ML} function f _{(w, D ML),} a dose correction factor f for the MPC can be calculated easily in a short time.

  As the shot division step (S102), the shot division unit 50 receives drawing data and divides each figure defined in the drawing data into shot figures. In order to draw a graphic pattern by the drawing apparatus 100, it is necessary to divide each graphic pattern defined in the drawing data into a size that can be irradiated with one beam shot. Therefore, the shot dividing unit 50 divides the graphic pattern indicated by the drawing data into a size that can be irradiated with one shot of the beam.

  As the shot figure data generation step (S104), the shot figure data generation unit 52 performs a plurality of stages of data conversion processing on the drawing data to generate shot data for each shot figure. In the shot data, for example, a figure type (graphic code), a figure size, and an irradiation position (coordinates) are defined. The shot data is output to the storage device 142 and stored.

  On the other hand, in parallel with the shot division step (S102) and the shot figure data generation step (S104), the pattern density calculation step (S110), the dose correction coefficient calculation step (S114), and the dose calculation step (S114). Do. Here, parallel processing is performed as an example, but each step may be performed in series.

As the pattern density calculation step (S110), the pattern density calculation unit 60 calculates the pattern density D _ML of the mesh area in which each figure is arranged among a plurality of mesh areas in which the drawing area is virtually divided into a predetermined size. . The pattern density calculation unit 60 is an example of an area density calculation unit.

FIG. 7 is a diagram illustrating an example of a mesh region in the first embodiment. In FIG. 7, when performing MPC, for example, it is preferable to perform mesh division with a size approximately equal to the radius of influence of the microloading effect. For example, a size of 2 to 3 μm is suitable. In FIG. 7, the mesh area for MPC is indicated by a solid line. Here, when performing proximity effect correction using an electron beam in addition to MPC, mesh division is performed with a size of about 1/10 of the radius of influence of the proximity effect. For example, mesh division is performed with a size of 1 μm. Then, the pattern density is calculated for each proximity effect mesh. Although not shown in FIG. 1, when the proximity effect correction is performed by the drawing apparatus 100, it is preferable to obtain the pattern density of the MPC mesh region from the pattern density calculated by the proximity effect mesh. Further, the pattern density D _ML of each mesh area for MPC may be interpolated using the values of the surrounding mesh areas for MPC. Alternatively, it is divided into sub-mesh (for example, about 1/10 of the influence radius of the microloading effect) with a smaller mesh size, and the pattern density value in the sub-mesh is obtained for each mesh area for MPC. The convolution calculation may be performed after that.

As the dose correction coefficient calculation step (S114), the dose correction coefficient calculation unit 64 corrects the line width dimension of the figure with respect to the correction direction using the line width dimension w and the pattern density _DML as parameters for each figure. f (w, D _ML ) (an example of a correction coefficient) is calculated. The dose correction coefficient calculation unit 64 is an example of a correction coefficient calculation unit. Specifically, the dose correction coefficient calculation unit 64 reads out the parameter of the function of the dose correction coefficient f (w, D _ML ) from the storage device 148 and calculates the line width dimension w defined in the pattern data of each figure. The dose correction coefficient f (w, D _ML ) is calculated using the obtained pattern density D _ML . Here, since the function of the dose correction coefficient f (w, D _ML ) using the line width dimension w and the pattern density D _ML as parameters is obtained in advance, the dose correction coefficient f ( w, D _ML ) can be calculated. The obtained dose correction coefficient f (w, D _ML ) is output to the storage device 144 and stored therein.

  FIG. 8 is a diagram showing an example of a plurality of figures constituting the pattern in the first embodiment. FIG. 8 shows an example of a so-called L-shaped pattern that extends as the pattern 20 changes in line width on the way. The pattern 20 is divided into a plurality of figures 22 a, b, c,... By fracturing processing before data is input to the drawing apparatus 100. Here, an important size in each figure is not the longitudinal direction (line direction) of the pattern 20 but the line width dimension orthogonal to the pattern 20. Therefore, it is the line width dimension in the direction orthogonal to the longitudinal direction (line direction) of the pattern 20 that needs to correct the dimensional variation due to the mask process. However, in the conventional drawing data, only the figure code, coordinates, x direction size, and y direction size of each divided figure are defined, and the line width dimension in the direction to be corrected (correction direction) is not defined. . Therefore, it is difficult to specify the correction direction as it is. Therefore, in the first embodiment, in addition to the graphic code, coordinates, x-direction size, and y-direction size of the graphic, the line width dimension w in the correction direction is defined in the pattern data of each graphic of the drawing data. Configured. In the example of FIG. 8, for example, for the divided figure 22a, in addition to the coordinates (x1, y1) and the size (Lx1, Ly1), a line width dimension w1 is further defined. The same applies to the other figures 22b, c,. Even when the extending direction of the pattern 20 is changed in the middle, the line width dimension in the direction orthogonal to the longitudinal direction (line direction) of the pattern 20 after the change may be defined in the pattern data of the figure. In the example of FIG. 8, for example, for the divided figure 22n, in addition to the coordinates (x17, y17) and the size (Lx17, Ly17), a line width dimension w17 is defined. Therefore, in the dose correction coefficient calculation step (S114), the dose correction coefficient f can be easily obtained using the line width dimension w as a parameter.

  As the dose calculation step (S114), the dose calculation unit 54 (first dose calculation unit) divides the drawing area into mesh areas of a predetermined size, and each mesh is located within the mesh. The irradiation amount (first irradiation amount) of the electron beam 200 for drawing is calculated. Here, when calculating the irradiation amount corrected for the proximity effect by the electron beam, the irradiation amount is calculated for each proximity effect mesh as described above. At that time, the pattern density in the proximity effect mesh is used. However, in the first embodiment, as will be described later, the dose correction coefficient f is used to correct the irradiation amount corrected for the proximity effect by the electron beam, so that the proximity effect correction may be shifted as it is. is there. Therefore, when calculating the irradiation amount corrected for the proximity effect by the electron beam, the irradiation amount calculation unit 54 sets the dose correction coefficient f for the MPC mesh region where the proximity effect mesh is located at the pattern density in the proximity effect mesh. It is preferable to use the multiplied value as the pattern density in the proximity effect mesh for the calculation. Thereby, the proximity effect of the electron beam can be corrected with respect to the pattern subjected to MPC. Then, the dose calculation unit 54 creates a dose map in which the dose calculated for each mesh is defined. The dose map is output to the storage device 142 and stored.

  As the dose correction step (S120), the dose correction unit 70 (second dose calculation unit) reads the dose (first dose) from the storage device 142 for each shot figure, and sets the dose to this dose. The dose (second dose) multiplied by the dose correction coefficient f of the corresponding figure is calculated. In other words, the dose before MPC correction is corrected by multiplying the dose before MPC correction by the dose correction coefficient f.

  As the deflection amount calculation step (S122), the deflection amount calculation unit 72 calculates the deflection amount to be applied to each deflector for each shot figure. For example, the deflection amount to the blanking deflector 212 can be adjusted by the irradiation time of the electron beam of each shot.

  As the drawing step (S124), the drawing unit 150 draws the figure on the sample 101 using the electron beam 200 with the corrected dose (second dose). Specifically, the following operation is performed.

  When the electron beam 200 emitted from the electron gun 201 (emission unit) passes through the blanking deflector 212, it is controlled by the blanking deflector 212 so as to pass through the blanking aperture 214 in the beam ON state. In the beam OFF state, the entire beam is deflected so as to be shielded by the blanking aperture 214. The electron beam 200 that has passed through the blanking aperture 214 until the beam is turned off after the beam is turned off becomes one shot of the electron beam. The blanking deflector 212 controls the direction of the passing electron beam 200 to alternately generate a beam ON state and a beam OFF state. For example, the voltage may be applied to the blanking deflector 212 when the beam is OFF, without applying a voltage when the beam is ON. The irradiation amount per shot of the electron beam 200 irradiated on the sample 101 is adjusted in the irradiation time of each shot.

  As described above, the electron beam 200 of each shot generated by passing through the blanking deflector 212 and the blanking aperture 214 illuminates the entire first shaping aperture 203 having a rectangular hole, for example, a rectangular hole, by the illumination lens 202. To do. Here, the electron beam 200 is first formed into a rectangle, for example, a rectangle. Then, the electron beam 200 of the first aperture image that has passed through the first shaping aperture 203 is projected onto the second shaping aperture 206 by the projection lens 204. The deflector 205 controls the deflection of the first aperture image on the second shaping aperture 206 and can change the beam shape and dimensions (variable shaping is performed). Such variable shaping is performed for each shot, and is usually shaped into different beam shapes and dimensions for each shot. Then, the electron beam 200 of the second aperture image that has passed through the second shaping aperture 206 is focused by the objective lens 207, deflected by the main deflector 208 and the sub deflector 209, and continuously moved. The desired position of the sample 101 arranged at 105 is irradiated. The drawing area is virtually divided into a plurality of stripe areas in a strip shape in the x or y direction, and drawing processing proceeds in units of stripe areas. The stripe region is virtually divided into subfields (SF) that can be deflected by the sub deflector 209. First, the electron beam 200 is deflected to the SF reference position where the main deflector 208 is shot. Since the XY stage 105 is moving, the main deflector 208 deflects the electron beam 200 so as to follow the movement of the XY stage 105. The sub deflector 209 irradiates each position in the SF.

As described above, in the first embodiment, pattern data before MPC is input to the drawing apparatus 100, and MPC is performed by correcting the irradiation amount in the drawing apparatus 100, so that the conventional manufacturing department on the user side This makes it possible to avoid the difficulty of applying corrections due to the difference between the two. Further, by previously _obtaining a function using only the line width dimension w and the pattern density D _ML as a variable parameter by experiment, and defining the line width dimension w in the correction direction in the pattern data of each figure, the drawing apparatus In 100, the dose correction coefficient f can be calculated at high speed in the drawing apparatus 100 only by calculating the pattern density _DML . Therefore, it is possible to more easily correct the dimensional variation caused by the mask process. As a result, highly accurate drawing can be performed.

Embodiment 2. FIG.
In the first embodiment, the drawing apparatus 100 inputs drawing data defining the line width dimension in the correction direction to the pattern data of each figure. However, the present invention is not limited to this. In the second embodiment, a configuration corresponding to the correction direction itself is described.

  FIG. 9 is a conceptual diagram illustrating a configuration of a drawing apparatus according to the second embodiment. In FIG. 9, except that a line width calculation unit 62 is added in the control computer 110, and a correction direction is defined instead of the line width dimension w in the pattern data of each figure stored in the storage device 140. The same as FIG.

  FIG. 10 is a flowchart showing main steps of the drawing method according to the second embodiment. In FIG. 10, the line width dimension calculation step (S112) is added between the pattern density calculation step (S110) and the dose correction coefficient calculation step (S114), and the pattern of each figure stored in the storage device 140. 3 is the same as FIG. 3 except that the correction direction is defined in the data instead of the line width dimension w. The contents not specifically described below are the same as those in the first embodiment.

  FIG. 11 is a diagram showing an example of a plurality of figures constituting the pattern in the second embodiment. As described above, the important size in each figure is not the longitudinal direction (line direction) of the pattern 20 but the line width dimension orthogonal thereto. Therefore, it is the line width dimension in the direction orthogonal to the longitudinal direction (line direction) of the pattern 20 that needs to correct the dimensional variation due to the mask process. However, in the conventional drawing data, only the figure code, coordinates, x-direction size, and y-direction size of each divided figure are defined, but the direction to be corrected (correction direction) is not defined. For this reason, it is difficult to specify the correction direction itself as it is. If the correction direction itself can be specified, the line width dimension w in the correction direction can be obtained from the figure code, the x direction size, and the y direction size. Therefore, in the second embodiment, in addition to the graphic code, coordinates, x-direction size, and y-direction size of the graphic, the correction direction is further defined in the pattern data of each graphic of the drawing data. In FIG. 8, coordinates (x1, y1), size (Lx1, Ly1), and line width dimension w1 are defined for the figure 22a obtained by dividing the pattern 20, but in FIG. 11, the coordinates (x1, y1), Size (Lx1, Ly1) and correction direction Y are defined. Similarly, the same applies to the other figures 22b, c,. Even when the extending direction of the pattern 20 is changed in the middle, the direction orthogonal to the longitudinal direction (line direction) of the changed pattern 20 may be defined in the pattern data of the figure as the correction direction. In the example of FIG. 11, for example, for the divided figure 22n, the correction direction X is further defined in addition to the coordinates (x17, y17) and the size (Lx17, Ly17).

  The contents of each process of the shot division process (S102), the shot figure data generation process (S104), and the pattern density calculation process (S110) are the same as those in the first embodiment.

  As the line width dimension calculating step (S112), the line width dimension calculating unit 62 calculates the width dimension of the figure in the correction direction indicated by the figure data. Specifically, the line width dimension calculation unit 62 inputs drawing data, and corrects from the figure code, coordinates, x-direction size, y-direction size, and correction direction defined in the pattern data of each figure. The line width dimension w in the direction is calculated. The line width dimension calculation unit 62 is an example of a width dimension calculation unit. The contents of each step after the dose correction coefficient calculation step (S114) are the same as those in the first embodiment.

As described above, in the second embodiment, pattern data before MPC is input to the drawing apparatus 100, and MPC is performed by correcting the irradiation amount in the drawing apparatus 100, so that the conventional manufacturing department on the user side This makes it possible to avoid the difficulty of applying corrections due to the difference between the two. Further, a function using only the line width dimension w and the pattern density D _ML as a variable parameter is obtained by experiment in advance, and a correction direction is defined in the pattern data of each figure. The dose correction coefficient f can be calculated at high speed only by calculating the line width dimension w and the pattern density _DML . Therefore, it is possible to more easily correct the dimensional variation caused by the mask process. As a result, highly accurate drawing can be performed.

Embodiment 3 FIG.
In the first embodiment, MPC is performed by correcting the irradiation amount. However, the correction method is not limited to this. In the third embodiment, a configuration in which MPC is performed by resizing a pattern dimension itself will be described.

  FIG. 12 is a conceptual diagram illustrating a configuration of a drawing apparatus according to the third embodiment. In FIG. 12, in the control computer 110, a resizing correction amount calculating unit 65 and a resizing processing unit 67 are added in place of the dose correction coefficient calculating unit 64, and a dose correcting unit 70 is deleted. Except for this, it is the same as FIG. The contents not specifically described below are the same as those in the first embodiment.

  FIG. 13 is a flowchart showing main steps of the drawing method according to the third embodiment. In FIG. 13, the drawing method according to the third embodiment includes a pattern density calculating step (S110), a resizing correction amount calculating step (S202), a resizing step (S204), a shot dividing step (S206), and shot figure data. A series of steps of a generation step (S208), an irradiation amount calculation step (S210), a deflection amount calculation step (S220), and a drawing step (S222) are performed.

In the third embodiment, a simple model is set using the figure width dimension w and the pattern density D _ML as parameters. However, the simplified model in the third embodiment obtains the resizing correction amount f ′ by changing the resizing ratio R, the width dimension w, and the pattern density D _ML . The resizing correction amount f ′ is defined so as to satisfy the following relational expression (2).
(2) R = f ′ (w, D _ML )

FIG. 14 is a diagram illustrating an example of a test pattern in the third embodiment. In FIG. 14, an evaluation pattern 10 having a line width dimension w1 serving as a base of pattern densities D _ML = D _ML1 , D _ML2 , and D _ML3 is an original dose amount (a dose amount after proximity effect correction by an electron beam is preferable). Then, the resize ratio R is changed to draw on the test substrate in which the resist is applied on the light shielding film. For example, D _ML1 ≈ 0 (substantially 0%), D _ML2 = 0.5 (50%), D _ML3 = 1 (100%), and at each pattern density D _ML , R = 0.98 (98%) , 1 (100%), and 1.02 (102%), the evaluation pattern 10 that has been resized is drawn. Then, the dimension of the light shielding film pattern obtained by developing and etching the drawn test substrate is measured. Then, in addition to w = w1, waving w = w2, w3 · · · and the underlying line width w, _{likewise, D ML1} ≒ 0 (substantially _{0%), D ML2 = 0.5} (50 %), D _ML3 = 1 (100%), and resize processing at a resize ratio of R = 0.98 (98%), 1 (100%), 1.02 (102%) at each pattern density D _ML The evaluated evaluation pattern 10 is drawn. Then, the dimension of the light-shielding film pattern obtained by developing and etching the drawn test substrate is measured.

FIG. 15 is an example of a graph showing the correlation among the line width dimension, the pattern density, and the resizing rate in the first embodiment. In FIG. 15, as described above, the resizing ratio R, the width dimension w, and the pattern density D _ML are made variable, and the pattern resizing ratio obtained as a result of the experiment and corrected for the dimensional variation of the pattern due to the mask process is corrected. An example of a set of R, a width dimension w, and a pattern density _DML is shown. Then, the resizing ratio R, the width dimension w, and the pattern density D _ML are made variable, and the resizing ratio R obtained by performing the experiment and corrected for the pattern dimension variation caused by the mask process, the width dimension w, Then, a plurality of sets of pattern densities D _ML are acquired, and a function of the resizing correction amount f ′ (w, D _ML ) satisfying the expression (2) is calculated by fitting the plurality of sets. The function f ′ (w, D _ML ) based on the above experiment is performed as a pre-process before drawing starts. Then, parameters of the obtained function f ′ (w, D _ML ) are input from the outside to the storage device 148 and stored. Thus, _w, 'by inputting the _{(w, D ML),} resizing the correction amount for the MPC f' to _{D ML} function f in the drawing device can be calculated in a simple and with a short time.

  First, the contents of the pattern density calculation step (S110) are the same as those in the first embodiment.

In the resizing correction amount calculation step (S202), the resizing correction amount calculation unit 65 calculates a resizing correction amount f ′ (correction amount) for correcting the line width dimension w using the line width dimension w and the pattern density D _ML as parameters. To do. The resizing correction amount calculation unit 65 is an example of a correction amount calculation unit. Specifically, the resizing correction amount calculation unit 65 reads out the function parameters of the resizing correction amount f ′ (w, D _ML ) from the storage device 148, and calculates the line width dimension w defined in the pattern data of each figure. The resize correction amount f ′ (w, D _ML ) is calculated using the pattern density D _ML thus obtained. Here, since a function of the resizing correction amount f ′ (w, D _ML ) using the line width dimension w and the pattern density D _ML as parameters is obtained in advance by experiment, the resizing correction amount f in a short time for each figure. '(W, D _ML ) can be calculated. The obtained resize correction amount f ′ (w, D _ML ) is output to the storage device 144 and stored therein.

As the resizing step (S204), the resizing processing unit 67 resizes the line width dimension s in the correction direction with the resizing correction amount f ′ (w, D _ML ) for each figure. Specifically, it resizes shapes to resize the correction amount of the figure f '(w, D _ML) obtained by multiplying the line width w' in the line width w of the figure defined in the pattern data. In other words, the line width before MPC correction is corrected by multiplying the line width dimension of the figure before MPC correction by the resizing correction amount f ′ (w, D _ML ). Then, with respect to each resized figure, the same steps as in the past are performed.

  As the shot dividing step (S206), the shot dividing unit 50 inputs the pattern data of each resized figure and divides each figure defined in the pattern data into shot figures.

  As the shot figure data generation step (S208), the shot figure data generation unit 52 performs a plurality of stages of data conversion processing on the resized pattern data of each figure to generate shot data for each shot figure. In the shot data, for example, a figure type (graphic code), a figure size, and an irradiation position (coordinates) are defined. The shot data is output to the storage device 142 and stored.

  As the dose calculation step (S210), the dose calculation unit 54 divides the drawing area into mesh areas of a predetermined size and draws the resized figure located in the mesh for each mesh. The irradiation amount of the beam 200 is calculated. Here, when calculating the irradiation amount corrected for the proximity effect by the electron beam, the irradiation amount is calculated for each proximity effect mesh as described above. At that time, the pattern density in the proximity effect mesh is used. However, if the pattern density in the proximity effect mesh is calculated with the figure before resizing, the proximity effect correction may shift. Therefore, when calculating the irradiation amount with the proximity effect corrected by the electron beam corrected, the irradiation amount calculation unit 54 preferably uses the pattern density in the proximity effect mesh using the resized figure for the calculation. Thereby, the proximity effect of the electron beam can be corrected with respect to the pattern subjected to MPC. Then, the dose calculation unit 54 creates a dose map in which the dose calculated for each mesh is defined. The dose map is output to the storage device 142 and stored.

  Here, the dose calculation step (S210) is performed in parallel with the shot division step (S206) and the shot figure data generation step (S208), but the present invention is not limited to this. You may implement each process in series.

  In the deflection amount calculation step (S220), the deflection amount calculation unit 72 calculates the deflection amount to be applied to each deflector for each shot figure. Then, as the drawing step (S222), the drawing unit 150 draws the resized figure on the sample 101 using the electron beam 200.

As described above, in the third embodiment, pattern data before MPC is input to the drawing apparatus 100, and MPC is performed by correcting the line width dimension of the figure by resizing in the drawing apparatus 100. Thus, it is possible to avoid the difficulty of applying correction due to the difference in the manufacturing department on the user side. Further, by previously _obtaining a function using only the line width dimension w and the pattern density D _ML as a variable parameter by experiment, and defining the line width dimension w in the correction direction in the pattern data of each figure, the drawing apparatus Within 100, the resize correction amount f ′ can be calculated at high speed in the drawing apparatus 100 only by calculating the pattern density D _ML . Therefore, it is possible to more easily correct the dimensional variation caused by the mask process. As a result, highly accurate drawing can be performed.

Embodiment 4 FIG.
In the third embodiment, the drawing apparatus 100 inputs drawing data defining the line width dimension in the correction direction to the pattern data of each figure. However, the present invention is not limited to this. In the fourth embodiment, a configuration corresponding to an input of the correction direction itself will be described.

  FIG. 16 is a conceptual diagram illustrating a configuration of a drawing apparatus according to the fourth embodiment. In FIG. 16, except that a line width calculation unit 62 is added in the control computer 110, and a correction direction is defined in place of the line width dimension w in the pattern data of each figure stored in the storage device 140. This is the same as FIG.

  FIG. 17 is a flowchart showing main steps of the drawing method according to the fourth embodiment. In FIG. 17, a line width dimension calculating step (S112) is added between the pattern density calculating step (S110) and the resizing correction amount calculating step (S202), and the pattern of each figure stored in the storage device 140. 13 is the same as FIG. 13 except that the correction direction is defined instead of the line width dimension w in the data. The contents not specifically described below are the same as those in the third embodiment.

  As described above, the important size in each figure is not the longitudinal direction (line direction) of the pattern 20 but the line width dimension orthogonal thereto. Therefore, it is the line width dimension in the direction orthogonal to the longitudinal direction (line direction) of the pattern 20 that needs to correct the dimensional variation due to the mask process. However, in the conventional drawing data, only the figure code, coordinates, x-direction size, and y-direction size of each divided figure are defined, but the direction to be corrected (correction direction) is not defined. For this reason, it is difficult to specify the correction direction itself as it is. If the correction direction itself can be specified, the line width dimension w in the correction direction can be obtained from the figure code, the x direction size, and the y direction size. Therefore, in the fourth embodiment, as in the second embodiment, in addition to the graphic code, coordinates, x-direction size, and y-direction size of the graphic, a correction direction is defined in the pattern data of each graphic of the drawing data. It was configured as follows. As shown in FIG. 11, in the figure 22a, coordinates (x1, y1), size (Lx1, Ly1), and correction direction Y are defined. Similarly, the same applies to the other figures 22b, c,. Even when the extending direction of the pattern 20 is changed in the middle, the direction orthogonal to the longitudinal direction (line direction) of the changed pattern 20 may be defined in the pattern data of the figure as the correction direction. In the example of FIG. 11, for example, the correction direction X is defined for the divided figure 22n in addition to the coordinates (x17, y17) and the size (Lx17, Ly17).

  The contents of the shot division step (S102) are the same as those in the first embodiment. The contents of the line width dimension calculating step (S112) are the same as those in the second embodiment. The contents of each step after the resizing correction amount calculation step (S202) are the same as those in the third embodiment.

As described above, in the fourth embodiment, pattern data before MPC is input to the drawing apparatus 100, and MPC is performed by correcting the line width dimension of the figure by resizing in the drawing apparatus 100. Thus, it is possible to avoid the difficulty of applying correction due to the difference in the manufacturing department on the user side. Further, a function using only the line width dimension w and the pattern density D _ML as a variable parameter is obtained by experiment in advance, and a correction direction is defined in the pattern data of each figure. The resize correction amount f ′ can be calculated at high speed in the drawing apparatus 100 only by calculating the line width dimension w and the pattern density D _ML . Therefore, it is possible to more easily correct the dimensional variation caused by the mask process. As a result, highly accurate drawing can be performed.

  The embodiments have been described above with reference to specific examples. However, the present invention is not limited to these specific examples.

  In addition, although descriptions are omitted for parts and the like that are not directly required for the description of the present invention, such as a device configuration and a control method, a required device configuration and a control method can be appropriately selected and used. For example, although the description of the control unit configuration for controlling the drawing apparatus 100 is omitted, it goes without saying that the required control unit configuration is appropriately selected and used.

  In addition, all charged particle beam writing apparatuses and methods that include elements of the present invention and that can be appropriately modified by those skilled in the art are included in the scope of the present invention.

50 shot division unit 52 shot figure data generation unit 54 irradiation amount calculation unit 60 pattern density calculation unit 62 line width calculation unit 64 dose correction coefficient calculation unit 65 resize correction amount calculation unit 67 resize processing unit 70 irradiation amount correction unit 72 deflection amount calculation Part 100 Drawing apparatus 101 Sample 102 Electron barrel 103 Drawing room 105 XY stage 110 Control computer 112 Memory 120 Deflection control circuit 140, 142, 144, 148 Storage device 150 Drawing part 160 Control part 200 Electron beam 201 Electron gun 202 Illumination lens 203 First shaping aperture 204 Projection lens 205 Deflector 206 Second shaping aperture 207 Objective lens 208 Main deflector 209 Sub deflector 212 Blanking deflector 214 Blanking aperture 330 Electron beam 340 Sample 410 First aperture 411 Aperture 420 Second Aperture 421 Variable Shaped Aperture 430 Charged Particle Source

Claims (5)

A storage unit for storing each graphic data in which a coordinate of a reference position, a graphic size in the x direction, a graphic size in the y direction, and a correction direction are defined for each graphic forming a pattern in which a plurality of graphics are connected;
A width dimension calculation unit that calculates the width dimension of the figure in the correction direction indicated by the figure data;
Among a plurality of mesh regions virtually divided by a predetermined size of the drawing region, an area density calculation unit that calculates the pattern density of the mesh region where the figure is arranged;
A correction coefficient calculating unit for calculating by inputting the pattern density and the width by using a function obtained by experiment a correction coefficient for correcting the pre-Symbol width as a parameter,
A first irradiation amount calculation unit for calculating a first irradiation amount of a charged particle beam for drawing the figure;
A second dose calculator for calculating a second dose obtained by multiplying the first dose by the correction coefficient;
A drawing unit for drawing the figure on a sample using the charged particle beam of the second irradiation amount;
A charged particle beam drawing apparatus comprising: Each figure data in which coordinates of a reference position, a figure size in the x direction, a figure size in the y direction, and a width dimension of the figure in the correction direction are defined is stored for each figure constituting a pattern obtained by connecting a plurality of figures. A storage unit;
Among a plurality of mesh regions virtually divided by a predetermined size of the drawing region, an area density calculation unit that calculates the pattern density of the mesh region where the figure is arranged;
A correction coefficient calculating unit for calculating by inputting the pattern density and the width by using a function obtained by experiment a correction coefficient for correcting the pre-Symbol width as a parameter,
A first irradiation amount calculation unit for calculating a first irradiation amount of a charged particle beam for drawing the figure;
A second dose calculator for calculating a second dose obtained by multiplying the first dose by the correction coefficient;
A drawing unit for drawing the figure on a sample using the charged particle beam of the second irradiation amount;
A charged particle beam drawing apparatus comprising: A storage unit for storing each graphic data in which a coordinate of a reference position, a graphic size in the x direction, a graphic size in the y direction, and a correction direction are defined for each graphic forming a pattern in which a plurality of graphics are connected;
A width dimension calculation unit that calculates the width dimension of the figure in the correction direction indicated by the figure data;
Among a plurality of mesh regions virtually divided by a predetermined size of the drawing region, an area density calculation unit that calculates the pattern density of the mesh region where the figure is arranged;
A correction amount calculator for calculating by inputting the pattern density and the width by using a function obtained by experiment a correction amount for correcting the pre-Symbol width as a parameter,
For the figure, a resize processing unit for resizing the width dimension by the correction amount;
A drawing unit that draws a resized figure on the sample using a charged particle beam;
A charged particle beam drawing apparatus comprising: Each figure data in which coordinates of a reference position, a figure size in the x direction, a figure size in the y direction, and a width dimension of the figure in the correction direction are defined is stored for each figure constituting a pattern obtained by connecting a plurality of figures. A storage unit;
Among a plurality of mesh regions virtually divided by a predetermined size of the drawing region, an area density calculation unit that calculates the pattern density of the mesh region where the figure is arranged;
A correction amount calculator for calculating by inputting the pattern density and the width by using a function obtained by experiment a correction amount for correcting the pre-Symbol width as a parameter,
For the figure, a resize processing unit for resizing the width dimension by the correction amount;
A drawing unit that draws a resized figure on the sample using a charged particle beam;
A charged particle beam drawing apparatus comprising: Each figure is stored from a storage device that stores figure data in which the coordinates of the reference position, the figure size in the x direction, the figure size in the y direction, and the correction direction are defined for each figure constituting a pattern in which a plurality of figures are connected. Reading data and calculating a width dimension of the figure in the correction direction indicated by the figure data;
A step of calculating a pattern density of a mesh area in which the figure is arranged among a plurality of mesh areas virtually divided into a drawing area of a predetermined size;
A step of calculating by inputting the pattern density and the width by using a function obtained by experiment a correction coefficient for correcting the pre-Symbol width as a parameter,
Calculating a first dose of a charged particle beam for drawing the figure;
Calculating a second dose obtained by multiplying the first dose by the correction coefficient;
Drawing the figure on a sample using the charged particle beam of the second dose;
A charged particle beam drawing method comprising:

Images