JPH0353513A - Electron beam direct lithography device - Google Patents

Abstract

PURPOSE:To reduce the required patterning period and to conduct patterning in a highly efficient manner by a method wherein a lithography region is divided into the rectangular areas having half the size of a field, a pattern is drawn in the areas by conducting a vector scanning while a table is being moved, and at the same time, the starting time of patterning and the speed of table movement are properly set. CONSTITUTION:First, pertaining to the pattern data of the rectangular area 36 to be patterned in the first place, the data of starting point coordinate of a segment, and the length and direction of segment are read out from a pattern memory 20, and the X-axis deflection scanning data, with which the X-axis direction scanning and the Y-axis direction scanning of the main deflector 15 will be controlled, and Y-axis deflection scanning data are outputted. In association with the starting of patterning, a table 17 moves to the X-axis direction at a fixed speed of V, and as a result, the target beam irradiation point position on a substrate 16 is shifted to X-axis direction. The amount of shifting against the X-coordinate value of the target beam irradiation point of the data, to be outputted from a vector pattern generation circuit 21, is corrected by addition or substraction by the direction using an addition and substraction circuit 29, and the corrected data is inputted to the main deflection and distortion correcting circuit 30. The patterning in the rectangular area is conducted successively while the amount of shifting in X-axis direction of the table 17 is being corrected by the operation same as above-mentioned.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to an electron beam direct drawing device that directly deflects and scans an electron beam to draw on a printed circuit board placed on a moving table. ．． [Prior Art] In the field of semiconductor manufacturing, electron beams are scanned over objects such as wafers and mask plates based on CAD data.
Some devices draw a predetermined pattern while continuously moving a table on which an object is placed.

In this case, the table is continuously moved in the direction of one axis (hereinafter referred to as the X-axis), and first, a belt-shaped area that is long in the X-axis direction is drawn. If the other axis perpendicular to the X-axis is the Y-axis, the width of the belt-like area in the Y-axis direction is
Maximum deflection area of electron beam (hereinafter referred to as field)
(hereinafter referred to as the maximum deflection width). When one belt-like area is drawn, the table is moved stepwise in the Y-axis direction by the maximum deflection width to draw the next belt-like area. Repeat this until the entire drawing area has been completely drawn.

Among such writing methods using a continuous table movement type, focusing on the electron beam deflection scanning method, the currently commonly used methods include the raster scanning method and the combined raster/vector scanning method.

In the raster scanning method, drawing is performed by scanning the electron beam in the Y-axis direction within the maximum deflection width while continuously moving the table in the X-axis direction. This method scans a fixed length in the Y-axis direction, cuts off the electron beam at areas where there is no pattern, and fills in the pattern by irradiating the electron beam at areas where there is a pattern. The required drawing time remains constant regardless of the density or occupancy. Therefore, the smaller the pattern occupation rate of the substrate, the lower the efficiency from the viewpoint of throughput 1. However, since the deflection direction is always constant, it has the advantage of simplifying the deflection control system. On the other hand, there is another deflection scanning method called the vector scanning method, in which only the pattern portion to be drawn is randomly deflected and scanned within the field. Although the IH direction control system becomes more complex, the advantage is that the smaller the pattern occupancy of the substrate, the shorter the required writing time and the higher the efficiency. Therefore, by taking advantage of the advantages of both raster and vector,
A continuously moving table drawing method that uses both raster and vector scanning was devised. This method is described, for example, on pages 49 to 55 of the March 1984 issue of the magazine "Electronic Materials."
It is introduced under the title of electron beam direct lithography system VLS1000J. FIG. 5 is an explanatory diagram showing the division of the drawing area in this method, and FIG. 5(B) is an enlarged view of FIG. 5(A). In these figures, {1} is a wafer made of semiconductor material, and e) is the direction of movement of the table (not shown) for wafer (1), as shown by the dashed line in the same figure (A). X
The main stripe is divided in the Y-axis direction perpendicular to the axis, and its width W is equivalent to the maximum deflection width of the electron beam. (4) is a square main field provided by dividing the main stripe (3) in the X-axis direction as shown by the broken line in Figure (A), and has the same dimensions as the aforementioned field. (5l is a sub-stripe provided by dividing the main field (4) in the X-axis direction as shown by the dashed line in (B) of the same figure, {6} is a sub-stripe (the phrase is indicated by the dashed line in (B) of the same figure) This is a square sub-field divided in the Y-axis direction.The operation will be explained next.The table continuously moves in the X-axis direction, and the main field (4) in one main stripe (3) ) are sequentially drawn. When the drawing of one main stripe (3) is completed, the table moves by one main stripe in the Y-axis direction, that is, by W, and the main stripe in the next main stripe (3) is drawn. The fields (4) are drawn sequentially. The pattern in the main field (4) is drawn as follows: one sub-stripe {while scanning between the sub-fields (6) in the strip in a raster manner, The pattern in subfield {6} is drawn at high speed by vector scanning.During the drawing time of one substripe (phrase), the table continuously moves in the X-axis direction by one width of substripe (5). .

When the drawing of one sub-stripe (59) is completed, the next sub-stripe (5) is drawn in the same way.Due to the continuous movement of the table, the center of the sub-field (6), which is the target position, may shift during drawing. However, the position of the table is measured with a laser interferometer (not shown) and fed back to the beam deflection system (not shown) to constantly correct the drawing position.In this method, vector scanning is performed. The scanning range is only within subfield (6), and the scanning between subfields (6) is raster scanning, and the electron beam is randomly vector scanned at any position within the main field (4). Not there.

Now, when trying to apply this method to drawing a pattern mainly composed of line drawings, such as a printed circuit board pattern, first, CAD pattern data covering the entire surface of the printed circuit board (not shown) is drawn in the main field (4). Furthermore, the pattern data within each main field G41 is divided into subfields (6), and the pattern data within these subfields (6) is divided into subfields (hereinafter referred to as field division). 6
), it is necessary to arrange them in a certain order in memory according to the raster scanning order between them. The main purpose of dividing the main field A) into subfields (6) with this method is to perform high-resolution electron beam deflection within the subfields (6) to achieve high accuracy on the submicron order for LSIs, etc. This is for drawing patterns.

However, when the electron beam deflection resolution of only deflection scanning within the main field (4) is sufficient, such as when drawing a printed circuit board pattern, it is preferable to draw the pattern within the main field (4) according to the CAD line drawing pattern data. Random deflection scanning only where there is, so to speak.
Pure vector scanning can be drawn more efficiently. [Problems to be Solved by the Invention] Since the conventional electron beam direct lithography apparatus is configured as described above, the CAD pattern data is divided into fields and further divided into subfields to form patterns within each subfield. It is necessary to arrange the data in a raster scanning order between subfields, and if this work is performed by computer software or software processing, the amount of data to be processed will be large, and therefore the processing time will increase. Ta. In addition, since each sub-field is deflected and scanned in a fixed order, it is possible to draw efficiently by randomly vector-scanning the main field, taking advantage of the fact that the printed circuit board pattern is horizontally marked with line drawings. However, there was a problem in that such vector scanning was not possible. This invention was made to solve the above-mentioned problems, and the processing time required for dividing and arranging CAD pattern data is shortened, and the table on which the object to be drawn is placed can be continuously moved. However, we have developed an electron beam direct lithography system that can perform efficient lithography with a short lithography time by randomly vector scanning only the areas where the pattern is present with the electron beam in the field according to CAD pattern data. The purpose is to obtain. [Means for Solving the Problems] The electron beam direct writing device according to the present invention divides the writing area into belt-like areas whose width is the maximum deflection width of the electron beam, and further divides the belt-like area into In the horizontal direction, rectangular areas are divided into half lengths of the maximum deflection width, and the time required to draw each rectangular area is calculated by dividing the table on which the object is placed in the length direction of the belt-shaped area. When one side of the rectangular area reaches the center of the field, start drawing the rectangular area and draw the vector. Drawing by scanning is performed sequentially for each rectangular area.

[For production]

In the electron beam direct writing device according to the present invention, the writing area is divided into rectangular areas half the size of the field, but there is no need to divide it into smaller areas, and writing within the rectangular area is performed by vector scanning. At the same time,
Since the drawing start time and table movement speed are set appropriately, the drawing of one rectangular area is completed within the time that the entire rectangular area is within the field, and each rectangular area is drawn efficiently in sequence. .

[Embodiments of the invention]

An embodiment of the present invention will be described below with reference to the drawings. 1st
The figure is a block diagram showing the structure of an electron beam direct writing apparatus according to an embodiment of the present invention, and in the figure, (11)
is the cathode, (l2) is the electron beam emitted from the cathode, (
13) is a plunker that cuts off the electron beam (l2) as necessary, (l4) is an aperture that allows the electron beam (12) to pass through and is shaped, and (l5) is an electronic boom (l2).
2) in the X-axis direction ('
Continuous movement direction of the table as described in fit> Two sets of main deflection coils (15A), one for deflection and one for deflection in the Y-axis direction perpendicular to this
．． (15B>). (16) is a substrate with a photosensitive resist 1- (not shown) on the surface, (l
7) is a table on which the substrate (16) is placed, and is movable in the X- and Y-axis directions. (18
) is a computer into which CAD pattern data is input,
(l9) is a memory control circuit connected to the output side of the computer (l8), and (20) is a drawing pattern memory connected to the output side of the memory control circuit (l9), which is a pattern divided into rectangular areas as described below. data is stored,
(21) is a vector pattern generation circuit that receives pattern data from the drawing pattern memory (20) and generates X-axis and Y-axis deflection scanning data. (22) is a table control circuit that issues a command to move the table (17) based on a signal from the computer (18), and together with a table moving power device (not shown) constitutes a table moving means. The linear scale (24) is located close to the linear scale (23).
) to read the amount of movement of the table (17)
(25) is a direction discrimination and signal processing circuit, and the sensor (
24), one pulse is generated every time the table (!7) moves a predetermined distance corresponding to the resolution of the sensor (24), and the table (l7) is moved from its initial position. Along with this, a pulse train is sequentially output, and the direction of movement of the table (!7) is detected and a direction discrimination signal is output.

(26) is a counter that counts the pulse train from the direction discrimination and signal processing circuit (25) to count the amount of movement of the table (l7); (27) is a detector that constitutes drawing start means; Detects this when one side of the rectangular area of the drawing area reaches the center of the field as it moves. The detection signal resets the counter (26) and is also input to the vector pattern generation circuit (2l). (28) is a deflection correction amount conversion circuit that outputs beam position correction amount data obtained by digitizing the movement amount data of the table (l7) obtained by the counter (26) based on the beam positioning resolution at the time of writing; 23)-(26). (28) is used to monitor the table movement amount counting means.

(29) is an addition/subtraction circuit that forms the irradiation point position data correction means, and converts the X-axis deflection scanning data from the vector pattern generation circuit (2l) and the beam position correction data from the deflection correction amount conversion circuit (28). , and outputs X-axis deflection scanning data corrected by addition or subtraction based on the direction discrimination signal from the direction discrimination and signal processing circuit (25). (30)
is a main deflection distortion correction circuit that receives X-axis and Y-axis deflection scanning data from the addition/subtraction circuit (29) and the vector pattern generation circuit (2l), corrects the deflection distortion inherent in the electron optical system, and generates corrected deflection scanning data. , (3l) is a DAC (digital-to-analog converter) that converts the corrected deflection scanning data from the main deflection distortion correction circuit (30) from digital to analog values, and (32) is a main deflector based on the analog data output from the DAC. In the main deflection control power supply unit that supplies current to (l5), the above (21). (30) ~ (32
) constitutes the irradiation point position data generation means,
(33) is a planking power supply that supplies voltage to the planker (13) based on the signal from the vector pattern generation circuit (21). 2 and 3 are explanatory diagrams showing the division of the drawing area in order to explain the drawing procedure in the electron beam direct drawing apparatus shown in FIG. 1. In FIG.
), (35A). (35B) is a belt-shaped area provided by dividing the drawing area (34) in the Y-axis direction, the width of which is equal to the maximum deflection width W of the electron beam (21), and although not shown, the drawing area (34) is provided throughout the entire area. Figure 3 shows details of the belt-shaped areas (35A) and (35B) in Figure 2.
6〉 is a large number of rectangular areas created by dividing the belt-like areas (35A) and (35[1) in the length direction at intervals of W/2, and when distinguishing them individually, the rectangular areas Ntt
+N12~Nu~+N211 N22~N26~. Next, we will explain the operation. Print L/Substrate pattern C
As the output of the AD, pattern data is transmitted to a computer (l8) via an online communication circuit or magnetic tape (both not shown).
) is input. Inside the computer (18), this pattern data is divided into rectangular areas (36), re-edited, and converted into direct drawing pattern information in binary format. This direct drawing pattern information is expressed as, for example, starting point coordinates, line segment length, and direction as digital values in binary format for each line segment of the drawing pattern, and this information is transmitted from the computer (18) via the memory control circuit (19). is transferred and stored in the drawing pattern memory (20).At the start of drawing, the rectangular area to be drawn first (36
) Regarding the pattern data (the drawing order will be described later), data on the starting point coordinates, line segment length, and direction of one line segment are read from the drawing pattern memory (20) and input to the vector pattern generation circuit (2!). It will be done. The vector pattern generation circuit (21) is controlled by electronic logic such as a counter, and receives the above three types of data.
) outputs X-axis deflection scan data and Y-axis deflection scan data that control the X-axis direction scan and Y-axis direction scan. With the start of drawing, the table (17} is moving at a constant speed V in the X-axis direction, and therefore the target beam irradiation point position on the substrate (!6) shifts in the X-axis direction.The amount of this shift is the linear scale (23), the sensor 《20
is measured and obtained as digital data from the old direction correction amount conversion circuit (28). Therefore, the addition/subtraction circuit (29
), the above-mentioned shift 1 amount is added to the X coordinate value of the target beam irradiation point of the data output from the vector pattern generation circuit (2l) according to the direction of movement. Or correct by subtraction, and the corrected data is used in the main deflection distortion correction circuit (30
) is input. Note that data related to the Y-axis direction does not require such correction. After the deflection distortion inherent in the electron optical system is corrected by the deflection distortion correction circuit (28), the DAC (31)
The main deflection control power supply section (32
), which causes two sets of main deflection coils (15A) for deflection in the X-axis and Y-axis directions of the main IQ deflector (15).
<15B) is supplied with current, and the electron beam (l2>
Vector scanning is performed. As above, 11! When vector scanning is completed, the drawing pattern memory (2
The data for the next line is read from 0), and the same movement f
Drawing within the rectangular area (36) is sequentially performed while correcting the amount of movement of the table (17) in the X-axis direction by t.

Figure 4 is a slightly generalized version of the rectangular area (36) in Figure 3, with a belt-shaped area (35A) extending in the length direction. It is shown as being divided by W. However, k is 0<
Let k<1 be a constant. FIG. 3A shows the state at the start of drawing of the leftmost rectangular area (N■,) in the figure. The table moves at a constant speed V in the direction of arrow A in the X-axis direction,
In the diagram of the belt-shaped area (35A), the field (37) indicated by the broken line is entered from the left end Yl, and a rectangular area (Hi.) is drawn. Rectangular area (Nt+)
In order to be able to deflect to any point within the rectangular area (N+ W+ (N+ 2)), the boundary Y between the rectangular areas (N+ W+ (N+ 2)
2 must be within the field (37), therefore, Y from the right end in the diagram of the field (37)
The distance lIIih to 1 is h≧kW ・・・・・・・・・
・・・・・・・・・・・・・・・・・・{1) The following condition is required. In addition, let T be the expected longest time among the times required to draw each rectangular area (36) with a different pattern occupancy rate, and the state after time T has elapsed from (A) in the same figure is shown in (r3) in the same figure. show. Field at this time (37)
In the figure, Y. The distance NLl is L, = (h + VT) ・・・・・・・・・・・・・・・
...(2)? If each rectangular area (36) is drawn at a time rrfIT '''C, then after a time nT (n is a positive integer) from the start of drawing, the rectangular area (N1...
), the distance Ln between the left side Yn and the right end of the field (37) in the drawing of the rectangular area N1n at that time is L.
n=h VT+ (n - 1)
(VT - kW) - (31.The rectangular area N, where drawing will be performed next, must be within the field (37), so Ln≦W...・・・・・・・・・
...(4) n≧kW ...
It is necessary to satisfy the condition ・・・・・・・・・・・・・・・+51. In order for equation (4) to hold regardless of the value of n, VT-kW in the third term on the right side of equation 13) must be 0.
On the other hand, similarly (for formula 4 to hold, V T - 1c W becomes O or positive. Therefore, V T = k W . . .・
......(6). (31, (41,
(From formula 61, W≧h+VT=h+kW ・・・・・・
・・・(7) is derived, and from equations (1) and (7), W≧h+kW≧2kW ・・・・・・・・・・・・(
8).゜． k≦1/2 ・・・・・・・・・
...(9). Therefore, #tI most efficiently
To perform J-stroke, k = 1/2...
・・・・・・Divide as αω and create a rectangular area (36)
It is better to set In other words, as shown in Figure 3, the size of the rectangular area {36> is 1/1 of the field (37).
It becomes 2.

In this case, the moving speed V of the table is (6). From the αω formula, it is determined as V=W/2T (1l).

Next, the procedure for drawing each rectangular area {36) divided into 1/2 the size of the field (37) as described above will be explained with reference to FIGS. 2 and 3. In FIG. 2, first, the table (17) is moved in the direction of arrow B in the X-axis direction and in the direction of arrow D in the Y-axis direction, and the belt-like area (3
5A}, the left side Y. After aligning the midpoint of the field with the center of the field, draw the rectangular area Nil while continuously moving the table (l7) in the direction of the arrow A at a constant distance τ V=W/2T. After the time T has elapsed, the table (l7) moves by a distance W/2, and the left side in the diagram of the rectangular area N12, that is, the boundary Y2 between the rectangular areas NllN12, reaches the center of the field, which is detected by the detector ( 27) is detected and drawing of the rectangular area Nl2 begins. Naturally, by this time the drawing of the rectangular area Nil has been completed. Sequentially draw each rectangular area (36) until it reaches the right end in the drawing of the belt-like area (35A), then move the table (!7) in the direction of arrow C by W↓n steps, and then move it in the direction of arrow B.
Draw a belt-shaped area (35n) while continuously moving in the direction of
Starting from 21, repeat from right to left in the opposite direction to the belt-shaped area (35A). In this way, the odd-numbered belt-like areas (35A) meander from left to right in the figure, and the even-numbered belt-like areas (35A) meander from right to left in the entire drawing area (35A).
4) Perform the drawing.

〔Effect of the invention〕

As described above, according to the present invention, the drawing area is divided into rectangular areas half the size of the field and drawing is performed, and since the drawing area is not divided into smaller areas, the processing time for dividing and arranging the pattern data is reduced. In addition, drawing is performed within the rectangular area by vector scanning while moving the table, and the drawing start time and table movement speed are set appropriately, so the smaller the pattern occupancy, the shorter the required drawing time. This has the effect of allowing short and efficient drawing.

[Brief explanation of drawings]

FIG. 1 is a block diagram showing the configuration of an electron beam direct writing device according to an embodiment of the present invention, and FIGS. 2, 3, and 4 show divisions of the writing area of the electron beam direct writing device of FIG. FIG. 5 is an explanatory diagram showing the division of the writing area of a conventional electron beam direct writing apparatus.9 In the figure, (l2) is the electron beam, (!5) is the main deflector, and (16) is the The board, (17) is the table, <34> is the drawing area, (35A>, (35B) is the bell-shaped area,
``36'' is a rectangular area, ``37'' is a field, and W is the maximum deflection width. Note that the same reference numerals in each figure indicate the same or corresponding parts.

Claims (1)

[Claims] In a device that performs writing by deflecting and scanning an electron beam onto a substrate placed on a continuously moving table, the writing area is a belt-shaped area whose width is the length of one side of the maximum deflection area of the electron beam. This belt-like area is further divided in the length direction into half lengths of one side of the maximum deflection area to provide rectangular areas, and the electron beam is irradiated based on the given drawing pattern information. means for generating irradiation point position data for randomly scanning the rectangular area; and a means for generating irradiation point position data for randomly scanning the rectangular area; and means for starting drawing of the rectangular area when one side of the rectangular area reaches the center of the maximum deflection area as the table moves. , comprising means for counting the amount of movement of the table, and means for correcting by adding or subtracting the amount of movement of the table to electron beam irradiation point position data based on the drawing pattern information. Beam direct writing device.