JPS606538B2 - Electron beam exposure method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an electron beam exposure method that improves exposure speed.

In integrated logic circuits, a large number of basic logic circuits such as OR and AND are arranged in advance on a semiconductor substrate, and in the wiring stage, certain parts are cut and certain parts are connected. Recently, it has been considered to manufacture logic circuits of

In that case, it is more efficient to form resist patterns for cutting and connecting wiring using electron beam exposure equipment, and it is possible to form finer patterns than with light exposure. be. Conventional electron beam exposure equipment uses an electron beam with a wavelength of approximately 0.01 [n], focuses this electron beam narrowly, and scans the resist while modulating the electron beam to expose a predetermined portion of the resist. be exposed to light.

However, the above-mentioned electron beam exposure apparatus, which scans with a narrow, focused electron beam, has a slow pattern data transfer rate, which has been an obstacle to high-speed exposure. The present invention is a new invention that improves the above-mentioned drawbacks of the conventional art, and its purpose is to provide an electron beam exposure method that can realize high-speed exposure with a simple configuration.

In order to achieve this purpose, the electron beam exposure method of the present invention extracts patterns of the same shape from the patterns to be exposed to form a plurality of pattern groups, and converts each of these pattern groups into a matrix to provide starting point information and pitch information. It is converted into matrix information consisting of pattern repetition information and on/off information of matrix lattice points, and based on this matrix information, an electron beam having the same cross section as the pattern of the pattern group is sent to the matrix lattice points for each pattern group. This method is characterized in that exposure is performed by scanning, and examples thereof will be described in detail below. FIG. 1 is a front view showing a pattern for raising an electrode window in an insulating film covering wiring formed on a semiconductor substrate.

As is clear from FIG. 1, this pattern consists of a group of rectangular patterns A with a length of 2 in the X direction and a length of 3 in the Y direction;
Group of pattern B with length 5 in x direction and length 2 in Y direction, ×
It consists of three types of pattern groups: a group of patterns C each having a length of 5 in the direction and a length of 5 in the Y direction. FIG. 2 is a front view showing only the group of patterns A extracted from the patterns of FIG. 1.

This pattern group is divided into a matrix of 6 in the x direction and 60 in the y direction. As is clear from Fig. 2, the upper left corner of each pattern A is
. The matrix information for [starting point X35, Y
:5], [pattern pitch Px: 10, Py: 10], [repetition number Nx: 6, Ny: 6], and the matrix lattice points of each pattern A are turned on. The off map looks like Figure 3. FIG. 4 is a front view showing only pattern B group extracted from the younger turtle pattern.

And this pattern group also has 60 in the X direction and 60 in the Y direction.
It is separated into a matrix. As is clear from Fig. 4, the upper left corner of each pattern B is (×
:10, Y:10), and this pattern B group is located on lattice points with a repeating number of 3×3 at 20 pitches in the X direction and 20 pitches in the Y direction. This kind of knowledge, pattern B
The matrix information about the group is [starting point X: 10, Y
:10], [pattern pitch Px:20, Py:20]
, [Number of repetitions Nx: 3, Ny: 3], and the matrix lattice points of each pattern B are turned on. The off map looks like Figure 5. FIG. 6 is a front view showing only pattern C group extracted from the patterns in FIG. 1.

And this pattern group also has 60 in the x direction and 60 in the y direction.
It is separated into a matrix. As is clear from Fig. 6, the upper left corner of each pattern C group is (
(X: 25, Y: 10), and this pattern C group is located on lattice points with a repeating number of 2×2 at 20 pitches in the X direction and 45 pitches in the Y direction. For this reason, the matrix information for pattern C group is [starting point X: 25
Y: 10], [Pattern pitch PX: 20, Py: 45
], [Number of repetitions Nx: 2 "Ny: 2], and the on/off map for the matrix lattice points of each pattern C is as shown in FIG. 7. The present invention uses the matrix information of each pattern group as described above. Electron exposure operation is performed. Fig. 8 is a block diagram showing a control mechanism of an apparatus for realizing electron beam exposure according to the present invention, in which 1 is an electron beam exposure apparatus main body, 2 is an electron gun, and 3 is an electron beam exposure apparatus body. Planking electrode plate, 4 is a pattern size determining section, 5 is an x direction deflection plate,
Reference numeral 6 denotes a Y-direction deflection plate, and 7 denotes a data table, on which wafers are read.

8 is a planking register, 9 is a planking amplifier,
10 is a pattern size register 11 is an electron beam pattern size forming amplifier, quantity 2 is an electron beam position specifying circuit in the X direction, a starting point position determining circuit 121, a digital/analog converter 122, a register 123, an adder 124,
It consists of a pattern pitch register 125, a counter 26, a coincidence circuit 27, and a repetition number register 28. Turtle 3 is Y
In the direction electron beam position designation circuit, starting point position determination circuit 1
31, digital-to-analog converter 132, register 13
3. Adder 134, pattern pitch register 135, counter 36, matching circuit 137, repetition number register 1
It consists of 38 pieces. 14 is a termination signal generator, 15 and 16
is an amplifier.

Next, the operation of the above control mechanism will be explained.

Among the matrix information of the exposure pattern, matrix information for pattern A is added to the control mechanism.
Of the matrix information, a starting point position signal in the x direction ("5" in the pattern shown in the second figure) is applied to the starting point position determining circuit 121, and a pitch signal ("1" in the pattern shown in the second figure) is applied to the pattern. Similarly, the repetition number signal (“6” in the pattern shown in the second diagram) is added to the repetition number register 28.

Similarly, the Y-direction starting point signal, pitch signal, and repetition number signal are applied to the starting point position determining circuit 31, pattern pitch register 35, and repetition number register 138 of the Y-direction electron beam position specifying circuit 13, respectively. Furthermore, the pattern size information of the electron beam irradiated onto the wafer (the length of pattern A is "2" in the x direction and "3" in the Y direction) is added to pattern size register 0, and the on/off switch of pattern A is The map information is added to planking register 8. Once all the information for pattern A has been added to the control mechanism, the exposure operation begins.

First, the starting point position determination circuit 121 sends the x direction starting point signal “5”.
” is added to the register 123, and the Y direction start point signal “5”
are added to the start point position determination circuit 131 and set in the register 133, respectively. Those signals are applied from each register to the analog-to-digital converters 122 and 132, and the signals converted to analog values are sent to the amplifier 15, respectively. and 16 to the x-direction deflection plate 5 and the Y-direction deflection plate 6, and the irradiation position of the electron beam is determined.

As is clear from FIG. 3, since the pattern A at the starting point position is on, no signal is emitted from the blanking register 8, and the electron beam emitted from the electron gun 2 passes through the blanking electrode plate 3. do. Then, when the electron beam passes through the pattern size determining section 4, the cross section x direction 3,
It is formed into a rectangular shape in the Y direction 2, and further includes an X direction deflection plate 5,
Pattern A is irradiated through the Y-direction deflection plate 6 to the female point position (the upper left corner of pattern A is at X:5, Y,5 position),
Expose the resist on the wafer. When this operation is completed, only the counter 126 of the electron beam position determining circuit 12 in the X direction is incremented by one, and the output of the register 23 is added to the adder 124. Since the pattern pitch number is always added to the adder 124 from the pattern pitch register 25, the adder 124 adds the pattern pitch number and the output from the register 123, and then resets the added number in the register 123. The signal reset to the register 123 is sent to the analog-to-digital converter 12
2 and converted into an analog value, the signal is added to amplifier 1
5 to the x-direction deflection plate 5, and the next irradiation position of the electron beam is determined.

As is clear from FIG. 3, since the second pattern A in the X direction is also on, the electron beam is irradiated to the second position on the wafer and exposes the resist on the wafer, as in the above case. When this operation is completed, the counter 126 of the electron beam position determining circuit 12 in the X direction is further increased by 1.
Further, the output of the register 23 is added to the adder 124.

The adder 124 adds the pattern pitch number and the output from the register 123, and then resets the added number in the register. When such an operation is repeated six times, the count value of the counter 26 becomes "6".

Also, since the pattern pitch register 128 is initially set to the repetition number "6", the matching circuit 127 -
I can count numbers. The register 123 is cleared by this coincidence signal, and the X-direction start point signal "5" is applied again from the start point position determination circuit 121 and set in the register 123. The coincidence signal from the coincidence circuit 127 is applied to the counter 136 of the electron beam position specifying circuit 13 in the Y direction, and the counter 136 increments by one.

Furthermore, the register 13 of the electron beam position designation circuit in the Y direction
The output of 3 is applied to adder 134. Since the pattern pitch number in the Y direction is always added to the adder 134 from the pattern pitch register 135, the adder 134 adds the pattern pitch number and the output from the register 133, and then stores the added number in the register. Reset to 133. The signal reset to register 133 is analog.

The signal applied to the digital converter 132 and converted into an analog value is applied to the Y-direction deflection plate 6 through the amplifier 15, changing the irradiation position of the electron beam by one mesh in the Y-direction. Then, a second scan in the X direction is performed, which is similar to the irradiation operation in the X direction. When such a scanning operation in the Y direction is performed six times, the count value of the counter 136 becomes “
6''. Further, since the pattern pitch register 138 is initially set to the Y-direction repetition number "6", the matching circuit 137 can match. Then, the sixth scanning operation in the x direction is performed, and when the matching circuit 127 of the electron beam position specifying circuit 12 in the x direction finds a final match, the end signal generating circuit 14 finishes all scanning for pattern A. This is detected and a pattern A exposure scanning operation end signal is generated. The control mechanism is all cleared by this end signal, and then the matrix information for pattern B is set, and the same operation as above is performed to perform the exposure operation for pattern B, and then the exposure operation for pattern C is performed. .

Although not shown, when the counter counts three termination signals from the termination signal generation circuit 14, the pattern A
, pattern B, and pattern C are completed, an exposure operation end signal is issued, and all the exposure operations are completed. When exposing, for example, 50,000 out of 100,000 mesh points using the apparatus of the present invention as described above, 1.
The amount of data is only 0x1 bits.

In contrast, with conventional equipment that performs exposure by finely scanning a narrowly focused electron beam, one point of data is
If expressed in 4 bits, 5 x 1 bit x 64 bits = 3
．． This is a huge amount of data, 2×1 bits.

This shows the economical superiority of the present invention.

As explained in detail above, the present invention minimizes the amount of data by matrixing the pattern for electron beam exposure, and processes the minimized data to perform electron beam exposure. The time required for exposure has become extremely short, and high-speed electron beam exposure has become possible.

Further, since the pattern data is also minimized, it is sufficient to use a smaller control circuit for the exposure apparatus, such as a buffer memory, than in a conventional exposure apparatus, and the electron beam exposure apparatus can be simplified.

[Brief explanation of drawings]

Fig. 1 is a front view showing an exposed electrode window pattern provided on an insulating film covering a semiconductor substrate, Fig. 2 is a front view showing only pattern A extracted from the electrode window pattern shown in Fig. 1, and Fig. 3. is an on-off map of pattern A, FIG. 4 is a front view showing only pattern B extracted from the electrode window pattern shown in FIG. 1, and FIG. 5 is an on-off map of pattern B.
Figure 6 shows pattern C from the electrode window pattern shown in Figure 1.
FIG. 7 is an on-off map of pattern C, and FIG. 8 is a diagram showing an embodiment of the present invention. This is a diagram. In the figure, 1 is the main body of the electron beam exposure apparatus, 8
is a planking register, 10 is a pattern size register, 12 is an electron beam position designation circuit in the X direction, and 13 is a Y
121 and 131 are starting point position determining circuits, 122 and 132 are digital-to-analog converters, 123 and 133 are registers, and 124
and 134 are adders, 125 and 135 are pattern pitch registers, 126 and 136 are counters, 12
7 and 137 are matching circuits, 128 and 138 are repeat number registers, and 14 is an end signal generator. Figure 1 Figure 2 Figure 3 Figure 4 Figure 5 Figure 6 Figure 7 Figure 8

Claims (1)

[Claims] 1 Extract patterns of the same shape from the patterns to be exposed to form a plurality of pattern groups, and convert each of these pattern groups into a matrix to create a matrix consisting of starting point information, pitch information, pattern repetition information, and on/off information of matrix lattice points. An electron beam exposure method is characterized in that the matrix information is converted into matrix information, and exposure is performed by scanning the matrix lattice points with an electron beam having the same cross section as the pattern of each pattern group for each pattern group.