JP3959238B2 - Charged beam drawing method and drawing data creation method - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a technique for drawing a fine pattern with high accuracy and high throughput, particularly charged beam drawing method and the drawing data creation method for collectively exposing a plurality of patterns using the character aperture, further relates to a drawing program .
[0002]
[Prior art]
Optical lithography in the semiconductor manufacturing process has been widely used for device production due to advantages such as process simplicity and low cost. Technological innovation is constantly being continued, and in recent years, miniaturization of elements of 0.2 μm or less is being achieved by shortening the wavelength (KrF excimer laser light source). For further miniaturization, the development of shorter wavelength ArF excimer laser light sources and Levenson type phase shift masks are being promoted, and these are expected as mass production lithography tools compatible with the 0.13 μm rule. However, there are many problems to realize this, and the time required for the development has been prolonged, and there is a concern that it will not be able to keep up with the speed of device miniaturization.
[0003]
In contrast, electron beam lithography, which is the first candidate for post-optical lithography, has been proven to be capable of processing up to 0.01 μm using a narrowly focused beam. Although there seems to be no problem for the time being in terms of miniaturization, there is a problem in throughput as a device mass production tool. That is, it takes time to draw fine patterns one by one. In order to shorten the drawing time, several apparatuses have been developed that employ an exposure method such as a partial batch exposure method (character projection method: CP method) that exposes repeated portions of an LSI pattern in a batch. Yes.
[0004]
However, even if these apparatuses are used, it has not yet reached the throughput of photolithography. The reason is that the number of stencil masks (character apertures) used to shape the beam into a repetitive pattern is the number (hundreds to thousands) required to expose the logic device with practical throughput. On the other hand, the number (100 at most) that can be prepared by the device is greatly insufficient.
[0005]
On the other hand, the present applicant has developed a partial batch exposure type electron beam drawing method by irradiating a part of an aperture having a device pattern shape provided on a character aperture with a beam, and transferring and exposing only a part of the aperture shape. Has already been proposed (Japanese Patent Application No. 2000-88967). In this method, three apertures are used, a rectangular beam shaped by the first and second apertures (beam shaping aperture) is irradiated to the third aperture (character aperture), and a part of the aperture shape is transferred and exposed. .
[0006]
When this exposure method is applied to the contact hole layer of a semiconductor device, an arbitrary number of hole patterns can be transferred at once, and the number of exposures can be greatly reduced compared to a variable shaped beam method in which holes are drawn one by one. Be expected. However, in order to realize this exposure method, drawing data for selectively irradiating the character aperture with an electron beam is necessary, but a method for creating such drawing data has not yet been realized.
[0007]
[Problems to be solved by the invention]
As described above, by using the first and second apertures for beam shaping and the third aperture for characters, an arbitrary number of hole patterns can be collectively transferred, and exposure is possible as compared with the normal variable shaped beam method. Although it is expected that the number of times can be greatly reduced, a method of creating drawing data for realizing this exposure method has not yet been realized.
[0008]
The present invention has been made in consideration of the above circumstances, and the object of the present invention is to easily create drawing data for selectively irradiating a character aperture with a charged beam, thereby improving drawing efficiency. It is another object of the present invention to provide a charged beam drawing method and drawing data creation method capable of improving the above, and a drawing program .
[0009]
[Means for Solving the Problems]
(Constitution)
In order to solve the above problems, the present invention adopts the following configuration.
[0010]
That is, the present invention is a charged beam drawing method in which a plurality of aperture patterns are simultaneously transferred onto a sample by selectively irradiating a character aperture on which aperture patterns of a predetermined shape are periodically arranged with a charged beam. And a step of moving at least one pair of opposing sides of the design pattern outward by a specified amount, a step of fusing the overlap between the patterns obtained by the movement step, and a step of fusing Separating the pattern into a plurality of rectangles, forming a charged beam based on each rectangular data obtained by the decomposition step, and irradiating a plurality of aperture patterns on the aperture with the shaped beam. It is characterized by including.
[0011]
The present invention is also used in a charged beam drawing method in which a plurality of aperture patterns are simultaneously transferred onto a sample by selectively irradiating a character aperture on which character-shaped aperture patterns are periodically arranged with a charged beam. A drawing data creation method for creating drawing data for defining a shape of a charged beam irradiated to an aperture for a character, the step of moving at least one set of opposite sides of a design pattern outward by a specified amount; A step of removing and fusing the overlap between the patterns obtained by the moving step, and a step of decomposing the pattern obtained by the fusing step into rectangles, and drawing the rectangle obtained by the decomposing step into drawing data Is output as
[0012]
Here, preferred embodiments of the present invention include the following.
(1) The amount of movement of the side of the design pattern is half of the space distance of the pattern arrangement.
(2) The opening pattern is a rectangular contact hole pattern, and in the movement process, the opposite sides of the design pattern are moved outward by a specified amount.
(3) In order to control the shape of the charged beam applied to the character aperture, the optical overlap between the two beam shaping apertures arranged on the charged beam source side with respect to the character aperture is controlled.
[0013]
In the present invention, the charged beam drawing apparatus is controlled by a computer, and a plurality of aperture patterns are formed on the sample by selectively irradiating a character aperture on which aperture patterns having a predetermined shape are periodically arranged. a computer readable program for transferring simultaneously, the program comprising: a first step of moving only outside a specified amount of at least one pair of opposing sides of the design pattern to be drawn on the specimen, The second step of removing and fusing the overlap between the patterns obtained by the first step, the third step of decomposing the pattern obtained by the second step into a plurality of rectangles, and the third step A charged beam is formed on the basis of each rectangular data, and an aperture pattern on the aperture is formed by the formed beam. And controls a computer to carry out a fourth step of irradiating a plurality of down, the.
[0014]
The present invention is also used in a charged beam writing method in which a plurality of aperture patterns are simultaneously transferred onto a sample by selectively irradiating a character aperture on a character aperture in which aperture patterns of a predetermined shape are periodically arranged. A computer-readable program for creating drawing data for defining a shape of a charged beam that irradiates a character aperture, wherein the program includes at least one set of design patterns to be drawn on the sample . A first step of moving the opposite sides outward by a specified amount, a second step of merging by removing overlap between the patterns obtained by the first step, and a pattern obtained by the second step The third step of decomposing the rectangle into rectangles and the rectangle obtained by the third step as drawing data And controls a computer to carry out and a fourth step of outputting.
[0015]
(Function)
According to the present invention, at least one pair of opposite sides of the design pattern is moved outward by a specified amount, and the obtained pattern is merged by removing the overlap between the obtained patterns and combining the obtained fused patterns into a plurality of rectangles. Drawing data for simultaneously selecting a plurality of opening patterns on the character aperture can be created by a relatively simple process of disassembling.
[0016]
For example, in a hole array pattern typified by a contact hole layer, drawing data for generating a hole array beam of an arbitrary number of arrangements by providing a hole array opening in a character aperture and irradiating a part of the hole array beam Can be easily created. That is, an arbitrary number of arrayed hole-shaped beams can be generated from one type of character opening. As a result, it is possible to collectively expose an arbitrary number of arrayed hole patterns with a single beam irradiation, which is significantly greater than the conventional variable shaped beam method in which one hole pattern is exposed at a time. In addition, the number of exposures can be reduced.
[0017]
Further, since only one type of character opening is required to generate an arbitrary number of hole-shaped beams, the occupation ratio on the character aperture in which only a limited number of character openings can be arranged can be greatly reduced. By assigning the vacant space to another character opening, the pattern can be exposed with the character beam more than before. As a result, the drawing efficiency is greatly improved, and the pattern drawing time is greatly shortened.
[0018]
DETAILED DESCRIPTION OF THE INVENTION
Before describing the embodiment, an electron beam drawing apparatus already proposed by the present applicant will be described.
[0019]
FIG. 1 is a schematic diagram for explaining the configuration of a partial batch exposure type electron beam exposure apparatus using three apertures. The basic operation of an electron beam exposure apparatus that irradiates a part of an opening having a device pattern shape provided on a character aperture and irradiates a part of the opening shape with reference to FIG.
[0020]
The electron beam 102 emitted from the electron gun 101 is adjusted in current density and Koehler illumination conditions by the first condenser lens 103 and the second condenser lens 104, and uniformly illuminates the first shaping aperture 105. The aperture image of the first shaping aperture 105 is formed on the second shaping aperture 107 by the first projection lens 106. The position where the electron beam 102 that has passed through the first shaping aperture 105 irradiates the second shaping aperture 107 is controlled by a shaping deflection system. As a result, the size of the electron beam 102 passing through the second shaping aperture 107 can be controlled. This shaping deflection system includes a shaping deflector 108, a shaping deflection amplifier 122, and a pattern data decoder 119 that sends deflection data to the shaping deflection amplifier.
[0021]
Further, the image of the second shaping aperture 107 is formed on the third shaping aperture (character aperture) 109 by the second projection lens 127. A plurality of openings (hereinafter referred to as character openings) having a basic pattern shape are provided on the third shaping aperture 109, and these character openings are sequentially selected according to the order defined in the drawing data. And irradiated with a beam. The character opening is selected by deflecting the beam by the character selection deflection system and controlling the beam irradiation position on the aperture. The character selection deflection system includes a character selection deflector 110, a character selection deflection amplifier 121, and a pattern data decoder 119 that sends deflection data to the character selection deflection amplifier 121.
[0022]
The irradiation position on the character opening of the electron beam that has passed through the second shaping aperture 107 is controlled by the character selection deflector 110. The irradiation area is determined by controlling the optical overlap of the first and second shaping apertures 105 and 107 with the shaping deflector 108. Thereby, it is possible to irradiate only a part of the character opening, and it is possible to generate different types of electron beams from one character opening.
[0023]
The electron beam 102 that has passed through the character aperture 109 is reduced by the reduction lens 111 and the objective lens 113 and is imaged on the sample 115. Then, the position of the electron beam 102 on the sample surface is set on the sample 115 by the objective deflector 112. The position of the electron beam 102 on the sample 115 is controlled by a pattern data decoder 119 that sends position data and an objective deflection amplifier 120 that applies a voltage to the objective deflector 112. The sample 115 is placed on the movable stage 114 together with the Faraday cup 116 and the electron beam dimension measuring mark base 117. Then, by moving the movable stage 114, the sample 115, the Faraday cup 116, or the electron beam dimension measurement mark base 117 can be selected.
[0024]
When moving the position of the electron beam 102 on the sample 115, the electron beam 102 is deflected by the blanking electrode 128 so that the electron beam 102 is not exposed to an unnecessary place on the sample 115, and the electron is emitted by the blanking aperture 129. The beam 102 is cut so as not to reach the sample surface. The blanking amplifier 123 controls the deflection voltage to the blanking deflector 128.
[0025]
All the drawing control data is stored in the pattern data memory 118, and the contents of the memory 118 are read by the pattern data decoder 119 to perform various controls. In the figure, 124 indicates a crossover image, 125 indicates heavy metal particles, and 126 indicates a backscattered electron detector.
[0026]
When this exposure method is applied to a contact hole layer of a semiconductor device, an arbitrary number of hole patterns can be collectively transferred by providing a hole array on the character aperture 109 and irradiating a part thereof with a beam. it can. As a result, the number of exposures can be greatly reduced as compared with the variable shaped beam method in which holes are exposed one by one. Also, compared to the case of preparing different character openings according to the number of holes arranged, it is possible to support an arbitrary number of hole arrays by preparing only one opening, and the number of character types to be arranged on the aperture As a result, the ratio of the pattern exposed using the character beam can be greatly increased, the number of beam irradiations can be reduced, and the drawing throughput can be improved.
[0027]
In order to realize such an exposure method, drawing data for selectively irradiating the character aperture with an electron beam is required. Therefore, in the present invention, drawing data is created as in the following embodiment.
[0028]
FIG. 2 is a flowchart for explaining a drawing data creation method and an electron beam drawing method according to an embodiment of the present invention.
[0029]
First, as a first step, at least one set of opposing sides of the design pattern is moved outward by a specified amount (P1). In the case of a contact hole pattern, all sides are moved outward by a specified amount. Next, as a second step, the overlap between the patterns obtained in the P1 step is removed, and the patterns are fused (P2). Subsequently, as a third step, the fusion pattern obtained in the P2 step is decomposed into a plurality of rectangles (P3). As a fourth step, an electron beam is formed based on the rectangular data obtained in step P3, and the device pattern opening on the character aperture 109 is partially irradiated using the formed electron beam (P4). .
[0030]
Next, the operation of each process of the present embodiment will be described more specifically with reference to the contact hole layer pattern of the semiconductor device shown in FIG. The design pattern shown in FIG. 3 is an example in which the hole dimensions and the arrangement pitch are arranged at a ratio of 1: 2, but this ratio is not necessarily 1: 2.
[0031]
By performing the P1 process on the design pattern shown in FIG. 3, the side of each hole pattern 10 in the design data is moved in the pattern outward direction as shown in FIG. In this embodiment, the sides are moved by a half of the distance between the hole patterns. As a result, adjacent hole patterns come into contact with each other. Next, by performing the P2 process, as shown in FIG. 5, the overlapping of the patterns is removed, the hole patterns 10 are fused, and one fused pattern 20 is formed. Next, by performing the P3 process on the fused pattern 20, the fused pattern 20 is decomposed into a plurality of rectangles 21, 22, and 23 as shown in FIG.
[0032]
In step P4, an electron beam is formed based on the rectangular data obtained in step P3, and the character opening on the character aperture is irradiated. In the apparatus of FIG. 1, the shaping deflector 108 controls the optical overlap of the first and second shaping apertures 105 and 107, and the shaped aperture image (electron beam) is character-selected by the character selection deflector 110. Irradiate a predetermined area on the aperture 109.
[0033]
FIG. 7 is a diagram for explaining the character openings (a) arranged in a matrix and the beam irradiation state (b). In this way, a character opening corresponding to the hole size and arrangement pitch of the design pattern is provided on the character aperture, and at the time of drawing, an electron beam is irradiated on a part of the character aperture, and a part of the character opening is transferred onto the sample surface. The
[0034]
In FIG. 7, the filled portion 30 indicates a contact hole, and the hatched portions 41, 42, and 43 indicate rectangular beams. In (b), (b1) corresponds to the rectangular beam 21, (b2) corresponds to the rectangular beam 22, and (b3) corresponds to the rectangular beam 23. In either case, the lower left of the figure is the coordinate origin of the rectangular beam. In addition, the character aperture does not necessarily have to be formed with only contact holes as shown in FIG. 7A, and is provided with contact hole groups having different pitches in a plurality of regions as shown in FIG. There may be.
[0035]
Thus, according to the present embodiment, rectangular data surrounding a plurality of hole patterns can be easily generated. Based on this rectangular data, it is possible to easily create control data for shaping an electron beam to the size and cutting out various types of shapes from one type of opening on the character opening.
[0036]
In FIG. 7, three types of transfer are shown as an example. However, 12 holes, 8 holes, and 3 hole patterns are transferred by one beam irradiation. When performing exposure one by one using the variable shaped beam method, it is necessary to irradiate the beam 23 times. In this embodiment, the exposure can be completed by irradiating the beam three times. Can do.
[0037]
Further, from the 6 × 6 array-shaped character openings shown in FIG. 7, 36 types of beams can be generated by irradiating a part of the beam openings. In the conventional character projection method, if the same type of character beam is to be generated, 36 types of character openings must be formed on the character aperture. In the case of the improved character projection drawing apparatus assumed in the present embodiment, since 36 types of beams can be generated using only one type of aperture, 35 free spaces are provided on the character aperture as compared with the conventional device. Is born. Openings having other shapes (for example, openings having different hole dimensions or different arrangement pitches) can be created in the empty space, and more various types of beams can be generated. For this reason, the throughput of the drawing apparatus can be significantly improved. As a result, the ratio of patterns that can be exposed using characters increases, and the number of exposures can be greatly reduced.
[0038]
In addition, this invention is not limited to embodiment mentioned above. In the embodiment, the contact hole is used as the pattern formed in the character aperture. However, it can be applied to a line and space pattern. In this case, it is not necessary to widen all the sides of the pattern outward in the P1 process, and only the sides parallel to the line direction may be widened outward. Further, the drawing apparatus used in the present invention is not limited to FIG. 1 and can be appropriately changed according to the specification. Furthermore, the present invention can be applied not only to an electron beam lithography apparatus but also to an ion beam lithography apparatus.
[0039]
The method described in the embodiment is written in a recording medium such as a magnetic disk (floppy disk, hard disk, etc.), optical disk (CD-ROM, DVD, etc.), semiconductor memory, etc. as a program that can be executed by a computer. The present invention can be applied to various devices, or can be applied to various devices by being transmitted through a communication medium. A computer that implements the present invention may be any computer that reads the program recorded on the recording medium and executes the above-described processing by controlling the operation by this program.
[0040]
In addition, various modifications can be made without departing from the scope of the present invention.
[0041]
【The invention's effect】
As described above in detail, according to the present invention, at least one pair of opposing sides of the design pattern is moved outward by a specified amount, and the overlap between the obtained patterns is removed and fused. The drawing data for simultaneously selecting a plurality of opening patterns on the character aperture can be created by a relatively simple process of decomposing the image into a plurality of rectangles. Therefore, it is possible to easily create control data for selectively irradiating the character aperture with a charged beam, thereby improving the drawing efficiency.
[Brief description of the drawings]
FIG. 1 is a schematic diagram for explaining the basic configuration and operation of an electron beam lithography apparatus.
FIG. 2 is a flowchart showing a procedure for creating electron beam drawing data according to an embodiment of the present invention.
FIG. 3 is a diagram showing an example of a design pattern of contact holes to be drawn.
FIG. 4 is a diagram showing a state in which the side of the pattern is moved outward by a quarter of the arrangement pitch in the P1 step.
FIG. 5 is a view showing a state in which pattern overlap is removed and fused by a P2 process.
FIG. 6 is a diagram showing a state in which a fusion pattern is decomposed into rectangles by the P3 process.
FIG. 7 is a diagram for explaining the irradiation state of a character opening and a rectangular beam.
FIG. 8 is a view showing an example of a character aperture in which a plurality of types of contact hole groups are arranged.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 10 ... Contact hole pattern 20 ... Fusion pattern 21, 22, 23 ... Rectangular pattern 30 ... Contact hole 41, 42, 43 ... Rectangular beam 101 ... Electron gun 102 ... Electron beam 103 ... First condenser lens 104 ... Second condenser lens 105 ... 1st shaping | molding aperture 106 ... 1st projection lens 107 ... 2nd shaping | molding aperture 108 ... Molding deflector 109 ... 3rd shaping | molding aperture (character aperture)
DESCRIPTION OF SYMBOLS 110 ... Character selection deflector 111 ... Reduction lens 112 ... Objective deflector 113 ... Objective lens 114 ... Movable stage 115 ... Sample 116 ... Faraday cup 117 ... Mark stage 118 for beam dimension measurement ... Pattern data memory 119 ... Pattern data decoder 120 ... Objective deflection amplifier 121 ... Character selection deflection amplifier 122 ... Molding deflection amplifier 123 ... Blanking amplifier 124 ... Crossover image 125 ... Heavy metal particle 126 ... Detector 127 ... Second projection lens 128 ... Blanking electrode 129 ... Blanking aperture

Claims (9)

A charged beam drawing method in which a plurality of aperture patterns are simultaneously transferred onto a sample by selectively irradiating a character aperture on a character aperture in which aperture patterns of a predetermined shape are periodically arranged,
A step of moving at least one set of opposite sides of a design pattern to be drawn on the sample to the outside by a specified amount, a step of removing overlap between patterns obtained by the moving step, and fusing A step of decomposing the pattern obtained by the fusion process into a plurality of rectangles, and forming a charged beam based on each rectangular data obtained by the decomposition step, and using the formed beam, a plurality of opening patterns on the aperture are formed. A charged beam drawing method comprising: an irradiation step.   2. The charged beam drawing method according to claim 1, wherein a side movement amount of the design pattern is a half of a space distance of the pattern arrangement.   3. The charged beam according to claim 1, wherein the opening pattern is a rectangular contact hole pattern, and in the moving step, the opposing sides of the design pattern are moved outward by a specified amount. Drawing method.   In order to control the shape of the charged beam applied to the character aperture, the optical overlap of two beam shaping apertures arranged on the charged beam source side with respect to the character aperture is controlled. The charged beam drawing method according to claim 1. A character aperture is used in a charged beam drawing method in which a plurality of aperture patterns are simultaneously transferred onto a sample by selectively irradiating a character aperture on a character aperture in which aperture patterns of a predetermined shape are periodically arranged. A drawing data creation method for creating drawing data for defining the shape of a charged beam irradiated on
A step of moving at least one set of opposite sides of a design pattern to be drawn on the sample to the outside by a specified amount, a step of removing overlap between patterns obtained by the moving step, and fusing And a step of decomposing the pattern obtained by the fusion step into rectangles, and outputting the rectangle obtained by the decomposition step as drawing data.   6. The drawing data creation method according to claim 5, wherein the amount of movement of the side of the design pattern is one half of the space distance of the pattern arrangement.   The drawing data according to claim 5 or 6, wherein the opening pattern is a rectangular contact hole pattern, and in the moving step, the opposing sides of the design pattern are moved outward by a specified amount. How to make. To control a charged beam drawing device by a computer and to irradiate a plurality of aperture patterns simultaneously on a sample by selectively irradiating a character aperture on a character aperture in which aperture patterns of a predetermined shape are periodically arranged. The program of
A first step of moving at least one set of opposite sides of the design pattern to be drawn on the sample outward by a specified amount, and a first step of merging by removing overlap between the patterns obtained by the first step. 2 steps, a third step for decomposing the pattern obtained by the second step into a plurality of rectangles, and forming a charged beam based on each rectangular data obtained by the third step, A computer-readable program for controlling the computer to perform a fourth step of irradiating a plurality of aperture patterns on the aperture. A character aperture is used in a charged beam drawing method in which a plurality of aperture patterns are simultaneously transferred onto a sample by selectively irradiating a character aperture on a character aperture in which aperture patterns of a predetermined shape are periodically arranged. A program for creating drawing data for defining the shape of a charged beam irradiated on
A first step of moving at least one set of opposite sides of the design pattern to be drawn on the sample outward by a specified amount, and a first step of merging by removing overlap between the patterns obtained by the first step. A computer for executing the second step, a third step for decomposing the pattern obtained by the second step into a rectangle, and a fourth step for outputting the rectangle obtained by the third step as drawing data. A computer readable program for controlling.

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