GB2151372A - Control of shutter position - Google Patents
Control of shutter position Download PDFInfo
- Publication number
- GB2151372A GB2151372A GB08428372A GB8428372A GB2151372A GB 2151372 A GB2151372 A GB 2151372A GB 08428372 A GB08428372 A GB 08428372A GB 8428372 A GB8428372 A GB 8428372A GB 2151372 A GB2151372 A GB 2151372A
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- Prior art keywords
- shutter
- shutter blade
- light
- blade
- exposure
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- 238000004519 manufacturing process Methods 0.000 claims abstract description 9
- 239000004065 semiconductor Substances 0.000 claims abstract description 9
- 230000004907 flux Effects 0.000 claims description 18
- 230000004044 response Effects 0.000 claims description 4
- 230000000903 blocking effect Effects 0.000 claims description 2
- 230000005540 biological transmission Effects 0.000 abstract description 5
- 230000003287 optical effect Effects 0.000 description 10
- 230000003247 decreasing effect Effects 0.000 description 8
- 238000010586 diagram Methods 0.000 description 8
- 108091008695 photoreceptors Proteins 0.000 description 7
- 230000007423 decrease Effects 0.000 description 5
- 230000000694 effects Effects 0.000 description 4
- 238000005286 illumination Methods 0.000 description 3
- 230000010354 integration Effects 0.000 description 3
- 230000002093 peripheral effect Effects 0.000 description 3
- 238000006243 chemical reaction Methods 0.000 description 2
- 230000007246 mechanism Effects 0.000 description 2
- 101100269850 Caenorhabditis elegans mask-1 gene Proteins 0.000 description 1
- 238000013459 approach Methods 0.000 description 1
- 238000012217 deletion Methods 0.000 description 1
- 230000037430 deletion Effects 0.000 description 1
- 230000000977 initiatory effect Effects 0.000 description 1
- 238000012986 modification Methods 0.000 description 1
- 230000004048 modification Effects 0.000 description 1
- 230000009467 reduction Effects 0.000 description 1
Classifications
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
- H01L21/00—Processes or apparatus adapted for the manufacture or treatment of semiconductor or solid state devices or of parts thereof
- H01L21/02—Manufacture or treatment of semiconductor devices or of parts thereof
- H01L21/04—Manufacture or treatment of semiconductor devices or of parts thereof the devices having potential barriers, e.g. a PN junction, depletion layer or carrier concentration layer
- H01L21/18—Manufacture or treatment of semiconductor devices or of parts thereof the devices having potential barriers, e.g. a PN junction, depletion layer or carrier concentration layer the devices having semiconductor bodies comprising elements of Group IV of the Periodic Table or AIIIBV compounds with or without impurities, e.g. doping materials
- H01L21/30—Treatment of semiconductor bodies using processes or apparatus not provided for in groups H01L21/20 - H01L21/26
-
- G—PHYSICS
- G03—PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
- G03F—PHOTOMECHANICAL PRODUCTION OF TEXTURED OR PATTERNED SURFACES, e.g. FOR PRINTING, FOR PROCESSING OF SEMICONDUCTOR DEVICES; MATERIALS THEREFOR; ORIGINALS THEREFOR; APPARATUS SPECIALLY ADAPTED THEREFOR
- G03F7/00—Photomechanical, e.g. photolithographic, production of textured or patterned surfaces, e.g. printing surfaces; Materials therefor, e.g. comprising photoresists; Apparatus specially adapted therefor
- G03F7/70—Microphotolithographic exposure; Apparatus therefor
- G03F7/70483—Information management; Active and passive control; Testing; Wafer monitoring, e.g. pattern monitoring
- G03F7/7055—Exposure light control in all parts of the microlithographic apparatus, e.g. pulse length control or light interruption
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- Physics & Mathematics (AREA)
- Engineering & Computer Science (AREA)
- General Physics & Mathematics (AREA)
- Condensed Matter Physics & Semiconductors (AREA)
- Manufacturing & Machinery (AREA)
- Computer Hardware Design (AREA)
- Microelectronics & Electronic Packaging (AREA)
- Power Engineering (AREA)
- Exposure And Positioning Against Photoresist Photosensitive Materials (AREA)
- Shutters For Cameras (AREA)
- Exposure Of Semiconductors, Excluding Electron Or Ion Beam Exposure (AREA)
Abstract
A shutter device with a servo system for controlling the movement of a rotary shutter blade 30. The shutter device includes a detecting system 37, 38 for detecting the stop position or state of the shutter blade. On the basis of an output from the detecting system and of an output from the servo system, the stop position of the shutter blade is precisely controlled whereby the light interception and the light transmission or exposure by the shutter device are made positive and stable. The device is used in the manufacture of semiconductor integrated circuits. <IMAGE>
Description
SPECIFICATION
A shuter device
BACKGROUND OF THE INVENTION
This invention relates to a shutter device and, more particularly, to a rotary type shutter device usable in a semiconductor device manufacturing apparatus.
Rotary type shutter devices usable in the semiconductor device manufacturing apparatuses are known, as disclosed in, e.g., U.S. Patent No. 4,350,428 issued September 21, 1982. In such shutter devices, however, the stop position of the rotary shutter blade is controlled by precisely controlling the rotational speed of the shutter blade. This disadvantageously requires a complicated control system for the precise control of the rotational speed.
There has already been proposed a rotary shutter device using a pulse motor as a drive source thereof, such as disclosed in Japanese Patent Application Laid-Open No. 56-55927. Use of pulse motor is, however, disadvantageous since the rise time and the moving speed of the pulse motor are not satisfactory. Thus, a bulky pulse motor is required to overcome such problems. In addition, the pulse motor inevitably involves a problem of vibration which is particularly serious upon the rise and end of the pulse movement.
SUMMARY OF THE INVENTION
It is therefore a principal object of the present invention to provide a shutter device which ensures precise control of the stop position of the shutter blade with a simple structure and minimizes the vibration.
In accordance with the present invention, there is provided a shutter device for exposure control in a semiconductor device manufacturing apparatus, comprising a shutter blade having a light transmittig portion for transmittig therethrough exposure light and a light intercepting portion for blocking the exposure light, and a DC motor for controlling the speed and position of the shutter blade.
These and other objects, features and advantages of the present invention will become more apparent upon a consideration of the following description of the preferred embodiments of the present invention taken in conjunction with the accompanying drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
Figure 1 is a perspective view showing a semiconductor device manufacturing apparatus to which a shutter device according to the present invention is applicable.
Figure 2 shows an optical arrangement of an illuminating optical system including a shutter device according to the present invention.
Figure 3 is a side view showing a shutter device according to one embodiment of the present invention.
Figure 4 is a plan view showing the shutter device of Fig. 3.
Figure 5 is a block diagram showing a control system of the shutter device shown in Figs. 3 and 4.
Figure 6 is a graph showing the characteristic of a speed instruction circuit shown in Fig. 5.
Figure 7 is a block diagram showing a modified form of control system for a shutter device, according to the present invention.
Figure 8 is a graph showing the characteristic of a position instruction circuit of the system shown in Fig. 7.
Figure 9 is a block diagram showing a further modified form of control system for a shutter device, according to the present invention.
Figure 10 is a block diagram showing a still further modified form of control system for a shutter device, according to the present invention.
Figure 11A and 11B are waveform views showing outputs of the processing circuit and the operational amplifier of the system, respectively. shown in Fig. 10.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
Figure 1 shows an alignment and exposure apparatus according to one embodiment of the present invention. The alignment and exposure apparatus includes a mask chuck 2 for holding a mask 1 having an integrated circuit pattern formed thereon, a reduction projection lens 3, a wafer stage 5 for supporting a wafer 4 and a casing 10 accommodating an illumination optical system for converging the mask illuminating light emitted from a light source 10a.
Figure 2 shows an optical arangement of the illumination optical system including a shutter device according to one embodiment of the present invention. The system includes the light source 1 0a as aforesaid, an elliptic mirror 11, a cold mirror 12, a shutter device 13, a multibeam forming optical element 14, a flat mirror 15, an optical filter 16, a condensing collimator lens 17 and another flat mirror 18. The system further includes another multi-beam forming optical element 19, an aperture 20, a flat or half mirror 21, another condensing collimator lens 22 and a light receiving element or photoreceptor 24 for detecting the quantity of light.
Designated by reference numeral 23 is a mask. The optics 14, 17, 19 and 22 are arranged such that a beam emitted from each of the points on the shutter device 13 is substantially uniformly distributed over the entire surface of the mask 23.
The shutter device according to the one embodiment of the present invention will now be described with reference to Fig. 3. The device includes a shutter blade 30, a rotational shaft 31 for the shutter blade 30, a gear 32 mounted on the rotational shaft 31 of the shutter blade, a
DC motor 33, a gear 34 mounted on an output shaft of the DC motor, a rotary encoder 35 and a gear 36 mounted on a rotational shaft of the rotary encoder. The device further includes a position detecting switch 37 such as a photo, interruptor disposed on the left-hand side of the shutter device, and another position detecting switch 38 disposed on the right-hand side of the device. In this embodiment, each of the position detecting switches 37 and 38 comprises a combination of a light-emitting diode with a photoreceptor.
When, in operation of the shutter device, the DC motor 33 rotates, the shutter blade 30 is rotated through the gears 34 and 32. With this rotation of the shutter blade 30, an effective light flux of the exposure light is alternately transmitted and intercepted, whereby the exposure is controlled. During this rotation of the shutter blade 30, the position detecting switches 37 and 38 detect the position, i.e., the rotating state of the shutter blade 30.
Fig. 4 is a plan view of the shutter device of Fig. 3 and shows the relative positional relation among the shutter blade 30, effective light flux 40 of the exposure light and position detecting switches 37 and 38. As illustrated, the shutter blade 30 in this embodiment is provided by a disk having three notches formed in the peripheral portion of the disk and at positions equidistantly spaced from each other along the periphery of the disk. Each of the notches has such shape that does not interfere the passagae of the effective light flux 40 when it is aligned with the effective light flux 40 during rotation of the shutter blade 30. The remaining areas of the peripheral portion of the disk are effective to intermittently intercept the effective light flux 40 during rotation of the shutter blade 30.Thus, the shutter blade 30 in this embodiment has three light transmitting portions and three light intercepting portions, all of which are located alternately on the peripheral portion of the blade 30.
In the position shown in Fig. 4, one of the notches or light transmitting portions of the shutter blade 30 is fully aligned with the effective light flux 40, so that the shutter blade 30 is in one of the light transmitting positions. In this Fig. 4 position of the shutter blade 30, each of the position detecting switches 37 and 38 is in its "ON" position (the position in which the light beam emitted from the light emittig diode is received by the photoreceptor). In this "ON" position, each of the position detecting switch 37 and 38 outputs an "ON" signal.
As the shutter blade 30 rotates clockwise as denoted by an arrow, one of the light intercepting portions of the shutter blade 30 begins to partially intercept the effective light flux 40. During this rotational movement of the shutter blade 30 during which the blade 30 partially intercepts the effective light flux 40, the position detecting switch 37 is maintained in its "ON position so that it continues to output an "ON" signal. However, the position detecting switch 38 is blocked by anither light intercepting portion of the shutter blade 30 so that it is placed in its "OFF" position (the position in which the light beam emitted from the light emitting diode is blocked). In this "OFF" position, the position detecting switch 38 outputs an "OFF"' signal.
As the shutter blade 30 further rotates clockwise until the effective light flux 40 is completely intercepted, the position detecting switch 38 is maintained in its "OFF" position by the abovementioned another light intercepting portion of the blade 30 while, on the other hand, the position detecting switch 37 is blocked by a third light intercepting portion of the blade 30 so that it is placed in its "OFF" position, generating an "OFF" signal.
As the shutter blade 30 further rotates clockwise, the effective light flux 40 which has been completely intercepted by the first one of the light intercepting portions of the shutter blade 30 is partially transmitted. During this rotational movement of the blade 30, the position detecting switch 37 is maintained blocked so that it continues to output the "OFF" signal while, on the other hand, the position detecting switch 38 is released from the second one of the light intercepting portions of the blade 30 so that it generates an "ON" signal.
As the shutter blade 30 further rotates clockwise, the effective light flux 40 is fully transmitted. At this time, both the position detecting switches 37 and 38 are released from the light intercepting portions of the blade 30 so that both of them output "ON" signals.
By repeating the above-described shutter blade movement, the exposure light is continuously controlled. The relation between the shutter blade and the position detecting switches is summarized in the following Table 1.
Table 1
POSITION OF BLADE 30 OUTPUT OF OUTPUT OF
RELATIVE TO BEAM 40 SWITCH 37 SWITCH 38
FULL TRANSMISSION ON SIGNAL ON SIGNAL
PARTIAL INTERCEPTION ON SIGNAL OFF SIGNAL
FULL INTERCEPTION OFF SIGNAL OFF SIGNAL
PARTIAL TRANSMISSION OFF SIGNAL ON SIGNAL
The control system of the DC motor drive type shutter device shown in Figs. 3 and 4 will now be described with reference to the block diagram shown in Fig. 5. The system includes an operation command circuit 50 which supplies to a processing circuit 51 a command signal for the shutter operation of light transmission, light interception or blade movement to its initial position. The operation command circuit 50 also supplies a reset command signal to an integrator 58.The processing circuit 51 is adapted to supply, on the basis of the command signal supplied from the operation command circuit 50 and of the positional information on the shutter blade 30 detected by the position detectors 37 and 38, an instruction signal, for instructing a predetermined amount of rotation, to a register 52 which stores therein the instructed amount of rotation. The processing circuit 51 is also adapted to reset a revolution counter 53 prior to the start of the shutter operation.
The system further includes a speed instruction circuit 54 which instructs the speed in accordance with the difference between the amount of rotation or revolution set in the register 52 and the actual amount of rotation indicated by the revolution counter 53 through the rotary encoder 35. A digital-to-analog (D/A) converter 55 is provided to convert the speed instruction signal supplied from the speed instruction circuit 54 into a voltage. Designated by a reference numeral 57 is a frequency-to-voltage (F/V) converter for converting, into a voltage, the output pulse frequency of the rotary encoder 35 indicative of the rotational speed of the shutter blade 30. An error amplifier 56 compares the output voltages from the D/A converter 55 and F/V converter 57 and amplifies the voltage difference. The amplified voltage difference is supplied to the DC motor 33.The integrator 58 integrates an output signal from the light receiving element 24 indicative of the quantity of light supplied from the light source 1 Oa when the shutter blade is in its transmitting position. When a predetermined quantity of light is reached, the integrator 58 outputs a signal to the operation command circuit 50 to cause it to supply a command signal to the processing circuit 51 for the light intercepting operation of the blade 30.
Fig. 6 shows the characteristic of the speed instruction circuit 54 shown in Fig. 5. In Fig. 6, the abscissa shows the difference between the designated amount of rotation stored in the register 52 and the amount of rotation indicated by the revolution counter 53, while the ordinate shows the output voltage of the speed instruction circuit 54. As illustrated in this
Figure, the speed instruction circuit 54 generates three kinds of outputs in accordance with the difference between the designated amounts of rotation in the register 52 and counter 53.More specifically, the speed instruction circuit 54 generates a zero output when the difference is not greater than a predetermined value A; a constant output of a predetermined level when the difference is not less than another predetermined value B; and, when the difference is between the predetermined values A and B, an output proportional to the difference.
The operation of the shutter device according to the disclosed embodiment will now be described with reference to Fig. 5. It is assumed that the shutter blade 30 is in its light intercepting position. First, the operation command circuit 50 supplies a command signal to the processing circuit 51 for the transmitting operation of the shutter, and supplies a reset signal to the integrator 58. Responsive to the operation command signal, the processing circuit 51 supplies to the register 52 a signal designating a predetermined amount of rotation, and, simultaneously therewith, the processing circuit 51 resets the couter 53. Since the motor 33 is not yet rotated, the difference between the amount of rotation designated by the register 52 and the amount of rotation indicated by the counter 53 is large.Therefore, the speed instruction circuit 54 supplies the constant output of a predetermined level shown in Fig. 6. Also, since the motor 33 is not yet rotated, the output from the F/V converter 57 is zero. Accordingly, the input voltage difference to the error amplifier 56 is large, such that the driving power of the DC motor 33 becomes higher while while the rise time thereof is shortened.
As the shutter blade 30 starts to rotate, the rotational speed is controlled through the rotary encoder 35. More particularly, the designated amount of rotation indicated by the register 52 and the amount of rotation of the counter 53 indicative of the current rotational position of the blade 30 are compared with each other by the speed instruction circuit 54. Then the speed instruction circuit 54 outputs a speed instruction signal in accordance with the positional difference. The D/A converter 55 receives the output signal from the speed instruction circuit 54 which is in the form of digital signal, and, after digital-to-analog conversion, the D/A converter 55 supplies a speed instruction voltage to the error amplifier 56.On the other hand, the F/V converter 57 converts the output of the rotary encoder 35, which is in the form of a pulse-like digital signal, into an analog voltage proportional to the actual rotational speed. In accoradnce with any error in the actual rotational speed voltage supplied from the F/V converter 57 with reference to the rotational speed instruction voltage supplied from the D/A converter 55, the error amplifier 56 supplies driving voltage to the DC motor 33. In this manner, the rotary encoder 35 connected to the DC motor 33 effects the speed feedback, to thereby control the speed of the shutter blade 30.
When the difference between the amounts of rotation designated by the register 52 and the counter 53 decreases as the DC motor 33 rotates, the rotational speed instruction voltage decreases as shown in Fig. 6, and, finally the shutter blade 30 is stopped. At this time, the processing circuit 51 confirms or discriminates the stop position of the shutter blade 30 with the aid of the position detecting switches 37 and 38. If both the switches 37 and 38 produce "ON" signals, the shutter blade 30 is just at a predetermined exposure position (lighttransmitting position). Therefore, the position control for the transmitting operation of the shutter blade 30 is terminated.If, on the other hand, one of the switches 37 and 38 produces an "ON" signal while the other produces an "OFF" signal, the shutter blade 30 is not at the predetermined position. Thus, the processing circuit 51 clears the counter 53 and applies a signal to the register 52 to set therein a minute amount of rotation to rotate the blade 30. More specifically, if the switch 37 produces an "OFF" signal while the switch 38 produces an "ON" signal, it is recognized that the shutter blade 30 has not yet fully reached the exposure position, so that the processing circuit 51 supplies such data that is effective to rotate the shutter blade 33 clockwise as viewed in Fig. 4 through a minute distance.If, on the other hand, the switch 37 produces an "ON' signal while the switch 38 produces "OFF" signal, it is recognized that the shutter blade 33 has overrun the exposure position, so that the processing circuit 51 supplies negative or positive- data which is effective to rotate the shutter blade 33 counterclockwise as viewed in Fig. 4 through a minute distance. In this manner, a fine position adjustment is effected so that the blade 30 is accurately located at the desired position. This fine position adjustment is effective to precisely define the starting position of the shutter blade 30 for the next shutter movement.
The driving mechanism of the shutter blade 30 is preferably arranged so that the number of revolutions or the rotational speed of the DC motor 33 reaches a predetermined constant value before an edge of the shutter blade (the leading edge of the light transmitting portion or of the light intercepting portion of the shutter blade) started from its stop position reaches the effective light flux 40 (Fig. 4) of the exposure light. With this arrangement, the shutter blade, i.e., the edge of the light transmitting or intercepting portion of the shutter blade passes across the effective light flux at a constant speed, whereby the surface area to be exposed to the exposure light is most efficiently illuminated and the illumination time is effectively reduced.After the trailing edge of the light transmitting or intercepting portion of the shutter blade passes the effective light flux 40, the rotational speed of the DC motor is steeply reduced so that the shutter blade is stopped with the movement of a slight angle of rotation.
During light transmitting operation of the shutter blade 30, a part of the light flux emitted from the light source 1 0a is directed to the photoreceptor 24. The photoreceptor 24 produces an output proportional to the quantity of light and supplies it to the integrator 58. The integrator 58, after it is cleared by the reset signal supplied from the operation command circuit 50, starts the integration and, when the value of integrated light quantity reaches a predetermined level, supplies an exposure ending signal to the operation command circuit 50. Responsive to this exposure ending signal, the operation command circuit 50 applies an instruction signal to the processing circuit 51 for the light intercepting operation of the shutter blade 30.In response to this operation instruction signal. the shutter blade 30 effects the light intercepting operation in the similar sequence as described in the foregoing. Whether or not the shutter blade 30 is stopped accurately at the light intercepting position is detected in the similar manner as described above, and the position of the shutter blade 30 is controlled until both the switches 37 and 38 produce "OFF" signals. respectively. In a case where the shutter device is incorporated into a stepper (a step-and-repeat type exposure apparatus), the above-described operations are repeated in synchronism with the movement of the wafer.
Fig. 7 is a block diagram showing a modified form of a control system for the shutter device, according to the present invention. In Fig. 7, those elements corresponding to or having similar functions as the elements shown in Fig. 5 are denoted by the same reference numerals. The conrol system includes an operation command circuit 50 which supplies to a processing ciruit 51 a command signal for the shutter operation of light transmission, light interception or blade movement to its initial position. The operation command circuit 50 also supplies a reset command signal to an integrator 58.The processing circuit 51 is adapted to supply, on the basis of the command signal supplied from the operation command circuit 50 and of the positional information on the shutter blade 30 detected by the position detectors 37 and 38, an instruction signal, for instructing a predetermined amount of rotation, to each of a register 52 and a revolution counter 53. The register 52 adapted to store therein the instructed amount of rotation. The processing circuit 51 is also adapted to reset the revolution counter 53 prior to the application of the instruction signal thereto. As shown in Fig. 7, the operation command circuit 50 supplies the register 52 with a predetermined number of clocks for subtraction.
The system further includes a position instruction circuit 54 which instructs the amount of movement in accordance with the difference between the amount of rotation or revolution set in the register 52 and the actual amount of rotation indicated by the revolution counter 53 through the rotary encoder 35. A digital-to-analog (D/A) converter 55 is provided to convert, into a voltage the signal on the amount of movement supplied from the position instruction circuit 54.
Designated by a reference numeral 57 is a frequency-to-voltage (F/V) converter for converting, into a voltage, the output pulse frequency of the rotary encoder 35 indicative of the rotational speed of the shutter blade 30. An operational amplifier 56 is provided to compare the output voltages from the D/A converter 55 and F/V converter 57 and amplifies the voltage difference.
More particularly, the operational amplifier 56 is adpated to provide an output corresponding to the output voltage difference between the D/A converter 55 and the F/V converter 57, i.e. the difference between the rotational speed corresponding to the amount of movement of the motor 33 designated by the position instruction circuit 54 and the actual rotational speed of the motor 33. The amplified voltage difference is supplied to the DC motor 33. The integrator 58 integrates an output signal from the light receiving element 24 indicative of the quantity of light supplied from the light source 1 0a when the shutter blade is in its transmitting position.When a predetermined quantity of light is reached, the integrator 58 outputs a signal to the operational command circuit 50 to cause it to supply a command signal to the processing circuit 51 for the light intercepting operation of the blade 30.
Fig. 8 shows the characteristic of the position instruction circuit 54 shown in Fig. 7. In Fig. 8, the abscissa shows the difference between the designated amount of rotation stored in the register 52 and the amount of rotation indicated by the revolution counter 53, while the ordinate shows the output voltage of the position instruction circuit 54. As illustrated in this
Figure, the position instruction circuit 54 generates three kinds of outputs in accordance with the difference between the designated amounts of rotation in the register 52 and counter 53.
More specifically, the position instruction circuit 54 generates a zero output when the difference is not greater than a predetermined value A; a constant output of a predetermined level when the difference is not less than another predetermined value B; and, when the difference is between the predetermined values A and B, an output proportional to the difference.
The operation of the shutter device having the control system shown in Fig. 7 will now be described with reference to Fig. 7. It is assumed that the shutter blade 30 is in its light intercepting position. First, the operation command circuit 50 supplies a command signal to the processing circuit 51 for the transmitting operation of the shutter, and supplies a reset signal to the integrator 58. Responsive to the operation command signal, the processing circuit 51 supplies to each of the register 52 and the counter 53 a signal designating a predetermined amount of rotation. The set predetermined amount or value in the register 52 is decreased by the clocks supplied from the operation command circuit 50.As the value set in the register 52 decreases, there occurs an increasing difference between the set value in the counter 53 and the decreasing value in the register 52, which difference appears in the position instruction circuit 54. Therefore, the D/A converter 55 produces a voltage corresponding to this difference, to thereby rotate the shutter blade 30 through the motor 33.
As the shutter blade 30 starts to rotate, both the rotational speed and the rotational position are controlled through the rotary encoder 35. More particularly, the rotary encoder 35 is adpated to apply a subtraction input to he counter 53 when it is actually rotated. Thus, the designated amount of rotation indicated by the register 52 and the amount of rotation of the counter 53 indicative of the current rotational position of the blade 30 are compared with each other by the position instruction circuit 54. Then, the position instruction circuit 54 outputs a signal relating to the amount of movement in accordance with the positional difference.The
D/A converter 55 receives the output signal from the position instruction circuit 54 which is in the form of digital signal, and, after digital-to-analog conversion, the D/A converter 55 supplies a position instruction voltage to the operational amplifier 56. As is well known in the field of servo system, this position instruction voltage is effective to control the rotational speed of the motor 33, as well as the rotational position thereof, in accordance with the magnitude of the voltage. On the other hand, the F/V converter 57 converts the output of the rotary encoder 35, which is in the form of a pulse-like digital signal, into an analog voltage proportional to the actual rotational speed.In accordance with any error in the actual rotational speed voltage supplied from the F/V converter 57 with respect to the position instruction voltage supplied from the D/A converter 55, the operational amplifier 56 supplies a driving voltage to the DC motor 33. In this manner, the combination of the rotary encoder 35, connected to the DC motor 33, the F/V converter 57 and the operational amplifier 56 effects the speed feedback, to thereby control the speed of the shutter blade 30.
The rotational operation of the motor 33 is still continued after the value in the register 52 is decreased to zero by the clocks supplied from the operation command circuit 50, until the value in the counter 53 is decreased to zero by the output pulses of the rotary encoder 35.
When, after the value in the register 52 becomes zero, the difference between the amounts of rotation designated by the register 52 and the counter 53 decreases as the DC motor 33 rotates, the position instruction voltage decreases as shown in Fig. 8, and, finally the shutter blade 30 is stopped when the value in the counter 53 becomes zero. At this time, the processing circuit 51 confirmes or discriminates the stop position of the shutter blade 30 with the aid of the position detecting switches 37 and 38. If both the position detecting switches 37 and 38 produce "ON" signals, the shutter blade 30 is just at a predetermined exposure position. Therefore, the position control for the transmitting operation of the shutter blade 30 is terminated.If, on the other hand, one of the switches 37 and 38 produces an "ON" signal while the other produces an "OFF" signal, the shutter blade 30 is not at the predetermined exposure position. Thus, the processing circuit 51 sets a minute amount of rotation in each of the register 52 and the counter 53 to rotate the motor 33 again. More specifically, if the switch 37 produces an "OFF" signal while the switch 38 produces an "ON" signal, it is recognized that the shutter blade 30 has not yet fully reached the exposure position, so that the processing circuit 51 supplies such data that is effective to rotate the shutter blade 33 clockwise as viewed in Fig. 4 through a minute distance.If, on the other hand, the switch 37 produces an "ON" signal while the switch 38 produces "OFF" signal, it is recognized that the shutter blade 33 has overrun the exposure position, so that the processing circuit 51 supplies negative or positive data which is effective to rotate the shutter blade 33 counterclockwise as viewed in Fig. 4 through a minute distance. In this manner, a fine position adjustment is effected so that the blade 30 is accurately located at the desired position. This fine position adjustment is effective to precisely define the starting position of the shutter blade 30 for the next shutter movement.
During light transmitting operation of the shutter blade 30, a part of the light flux emitted from the light source 1 0a is directed to the photoreceptor 24. The photoreceptor 24 produces an output proportional to the quantity of light and supplies it to the integrator 58. The integrator 58. after it is cleared by the reset signal supplied from the operation command circuit 50, starts the integration and, when the value of integrated light quantity reaches a predetermined level, supplies an exposure ending signal to the operation command circuit 50. Responsive to this exposure ending signal. the operation command circuit 50 applies an instruction signal to the processing circuit 51 for the light intercepting operation of the shutter blade 30.In response to this operation instruction signal. the shutter blade 30 effects the light intercepting operation in the similar sequence as described in the foregoing. Whether or not the shutter blade 30 is stopped accurately at the light intercepting position is detected in the similar manner as described above, and the position of the shutter blade 33 is controlled until both the switches 37 and 38 produce "OFF" signals. In a case where the shutter device is incorporated into a stepper (a step-and-repeat type exposure apparatus), the above-described operations are repeated in synchronism with the movement of the wafer.
Fig. 9 is a block diagram showing a further modifed form of control system for the shutter device, according to the present invention. In Fig. 9, those elements corresponding to or having similar functions as those shown in Fig. 7 are denoted by the same reference numerals. The Fig.
9 embodiment differs from the Fig. 7 embodiment in the point that the former does not include a F/V converter such as 57 in Fig. 7. Because of the deletion of such F/V converter, the actual rotational speed of the motor 33 can not be fed back to the output voltage of the operational amplifier 56, so that the rotational speed of the shutter blade 30 is uncontrolled. Since, however, the position of the shutter blade 30 is precisely controlled by means of the position detecting means (switches 37 and 38, etc.), no practical problem occurs in respect to the control of the amount of exposure.
The distribution of light intensity on the mask surface is substantially independent from the changes. with time, in the area of aperture (effective light transmitting area) of the shutter blade with the rotation thereof, owing to the optical system provided by the optics 14. 17, 19 and 22 described with reference to Fig. 2. Therefore, the amount of exposure on the mask surface is maintained substantially uniform.
Since the Fig. 9 system operates in the same manner as the Fig. 7 system except for the feedback as above. description thereof is omitted herein for the sake of simplicity of explanation.
Fig. 10 is a block diagram showing a still further modified form of control system for the shutter device, according to the present invention In Fig. 10, those elements corresponding to or having similar functions as those shown in Figs. 7 and 9 are denoted by the same reference numerals. The Fig. 10 embodiment differs from Fig. 7 embodiment in the point that a register and a position instruction circuit such as 52 and 54 in Fig. 7, as well as an F/V converter such as 57 in Fig. 7 are all deleted. Thus, the Fig. 10 system has a structure which is more simple as compared with that of the Fig. 9 system.
In Fig. 10 system, a limiter circuit 58 is provided between a D/A converter 55 and an operational amplifier 56 to prevent the operational amplifier 56 from applying an overcurrent to the motor 33. That is, if the D/A converter 55 outputs a voltage which causes the operational amplifier 56 to output a voltage such as shown by a broken line in Fig. 11 B, the actual output voltage of the operational amplifier 56 is limited to a voltage A, shown by a solid line in Fig.
11 B.
In operation of the Fig. 10 system, an operation command circuit 50 provides an exposure start instruction signal which is supplied to a processing circuit 51. Responsive thereto, the processing circuit 51 applies a signal to a revolution counter 53 to set therein a position instruction value corresponding to a predetermined amount of movement of the shutter blade 30 which is necessary to displace the shutter blade from its light intercepting position to the light transmitting position (exposure position). As shown in Fig. 11 A, the position instruction value is e.g. "100".When the position instruction value is set in the counter 53, the D/A converter 55 produces a voltage corresponding to the position instruction value, which voltage is applied, after being dropped to the predetermined level Av by the limiter circuit 58, to the DC motor 33 through the operational amplifier 56. With the actuation of the motor 33, the shutter blade 30 starts to rotate while the rotary encoder 35 starts to rotate to generate pulses indicative of the amount of rotation of the shutter blade 30. By these pulses generated by the rotary encoder 35, the value set in the counter 53 is decreased so that the output voltage of the
D/A converter 55 is gradually decreased in accordance with the rotation of the shutter blade 30.Namely, upon initiation of rotation of the motor 33, the predetermined voltage Av is supplied to the motor so that it is rotated at a higher speed. As the shutter blade 30 approaches its stop position, the rotational speed of the motor is decreased and, when the value in the counter 53 becomes zero, the motor is stopped. Subsequently, the processing circuit 51 detects, with the aid of the position detecting switches 37 and 38, whether or not the shutter blade 30 has fully reached the exposure position (fully open position). More specifically, if both the switches 37 and 38 produce "ON" signals, the processing circuit 51 no more supplies an additional position instruction signal to the counter 53.If, on the other hand, one of the switches 37 and 38 produces an "ON" signal while the other produces an OFF" signal, judgement such as shown in the above Table 1 is made, and on the basis of which, the processing circuit 51 supplies the counter 53 with a position instruction signal of a minute amount, such as " + 10" or " - 10" (Fig. 11A) in accordance with the direction of deviation, in order to further rotate the shutter blade 30 through a minute distance. Such operation is continued until both of the switches 37 and 38 produce "ON" signals, respectively.
When, after the shutter blade 30 is accurately stopped at the exposure position, the quantity of light integrated by the integrator 58 reaches a predetermined amount. The operation command circuit 50 produces an instruction signal for starting the light interception, similarly to the foregoing embodiments. In response to this instruction signal, the processing circuit 51 again sets a position instruction value in the counter 53 to start the rotation of the motor 33, so that the shutter blade 30 is rotated toward the light intercepting position. The succeeding operations are similar to those for the shutter opening movement except for that, in the position control during the shutter closing movement, the shutter blade 30 is controlled to be stopped at a position at which both the switches 37 and 38 produce "OFF" signals, respectively.
In accordance with the embodiments as has hitherto been described, a DC motor is employed as a drive source which, in co-operation with a rotary shutter blade, effectively diminishes the rise time until a predetermined rotational speed is reached and ensures a higher moving speed of the shutter blade and simplification of the shutter mechanism. Further, the positions of the components of the illuminating optical system including the shutter device are inter-related with each other such that substantially uniform exposure is assumed over the entire surface of the mask, as described hereinbefore, any slight irregularities in the rotational speed of the shutter blade would not result in uneven exposure.Since the shutter blade can be stopped at its stop position highly precisely, the diameter of the effective exposure beam can be close to the dimension of each of the light transmitting portion and light intercepting portion of the shutter blade. Actually in the embodiment shown in Fig. 4, each of the transmitting portion and intercepting portion has substantially the same dimension as the diameter of the effective light flux 40. Therefore, the useless operation of the shutter blade that the blade moves through an unnecessary distance and the time required therefor can be removed or minimized.
The use of a rotary shutter blade in the shutter device eliminates the difference between the amount of exposure at the movement starting position of the shutter blade and that at the movement #ending position of the blade and also diminishes uneven exposure in the exposure area. Moreover, the amount of exposure light is measured by integration, on the basis of which the shutter operation is instructed. Therefore, unevenness in the amount of exposure due to the changes, with respect to time, in the quantity of light of the light source can be decreased so that a constant amount of exposure is always ensured throughout the repeated exposure operations.
With these features of the present invention, highly dense pattern circuits can be massproduced efficiently and with a high throughput.
While the invention has been described with reference to the structures disclosed herein, it is not confined to the details set forth and this application is intended to cover such modifications or changes as may come within the purposes of the improvements or the scope of the following
Claims (8)
1. A shutter device for exposure control in a semiconductor device manufacturing apparatus, comprising:
a shutter blade having a light transmittig portion for transmitting therethrough exposure light and a light intercepting portion for blocking the exposure light; and
a DC motor for controlling the speed and position of said shutter blade.
2. A shutter device according to Claim 1, further comprising a rotary encoder, connected to said DC motor, for detecting the amount and speed of rotation of said DC motor.
3. A shutter device according to Claim 1, further comprising a plurality of position detecting switches for detecting the stop position of said shutter blade to correct it.
4. A shutter device according to Claim 1, wherein each of said light transmitting portion and light intercepting portion of said shutter blade has substantially the same dimension as a diameter of an effective light flux of the exposure light.
5. A shutter device according to Claim 1, further comprising means for detecting the quantity of exposure light and means for integrating the detected quantity of light, said intgrating means producing an output on the basis of which the rotational operation of said DC motor is instructed, whereby the exposure time is controlled.
6. A shutter device for exposure control in a semiconductor device manufacturing apparatus, comprising a shutter blade driven by a DC motor.
7. A shutter device for exposure control in a semiconductor device manufacturing apparatus, comprising a movable shutter blade, drive means for the shutter blade, sensing means for sensing movement of the shutter blade and feedback means for controlling the drive means in response to the sensing means.
8. A shutter device for exposure control in a semiconductor device manufacturing apparatus, substantially as herein described with with reference to the accompanying drawings.
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP58209939A JPS60102737A (en) | 1983-11-10 | 1983-11-10 | Shutter device |
Publications (3)
| Publication Number | Publication Date |
|---|---|
| GB8428372D0 GB8428372D0 (en) | 1984-12-19 |
| GB2151372A true GB2151372A (en) | 1985-07-17 |
| GB2151372B GB2151372B (en) | 1987-12-16 |
Family
ID=16581162
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| GB08428372A Expired GB2151372B (en) | 1983-11-10 | 1984-11-09 | Control of shutter position |
Country Status (3)
| Country | Link |
|---|---|
| JP (1) | JPS60102737A (en) |
| DE (1) | DE3441298A1 (en) |
| GB (1) | GB2151372B (en) |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| GB2369193A (en) * | 2000-06-21 | 2002-05-22 | Leica Microsystems | Laser scanning microscope and shutter |
| CN108663871A (en) * | 2017-03-31 | 2018-10-16 | 上海微电子装备（集团）股份有限公司 | A kind of shutter device |
Families Citing this family (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS61188152U (en) * | 1985-05-15 | 1986-11-22 | ||
| DE3772467D1 (en) * | 1986-06-13 | 1991-10-02 | Dainippon Screen Mfg | EXPOSURE SYSTEM. |
Citations (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| GB2038030A (en) * | 1978-12-15 | 1980-07-16 | Hewlett Packard Co | Optical beam director |
| GB2041576A (en) * | 1979-02-02 | 1980-09-10 | Leeds & Northrup Co | Electric drive unit control apparatus |
| GB2055487A (en) * | 1979-07-06 | 1981-03-04 | Jaeger | An adder of electrical pulses using an electric motor with position control |
| EP0032312A2 (en) * | 1979-12-31 | 1981-07-22 | Fanuc Ltd. | Control system for stopping spindle at predetermined rotational position |
| GB2116749A (en) * | 1982-03-03 | 1983-09-28 | Perkin Elmer Corp | Pen drive for recorder |
| EP0101051A2 (en) * | 1982-08-17 | 1984-02-22 | Sumitomo Electric Industries Limited | Method of position control by DC servomotor |
Family Cites Families (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US4350428A (en) * | 1979-10-09 | 1982-09-21 | Optimetrix Corporation | Shutter mechanism |
| JPS5655927A (en) * | 1979-10-15 | 1981-05-16 | Ushio Inc | Shutter device |
-
1983
- 1983-11-10 JP JP58209939A patent/JPS60102737A/en active Pending
-
1984
- 1984-11-09 GB GB08428372A patent/GB2151372B/en not_active Expired
- 1984-11-12 DE DE19843441298 patent/DE3441298A1/en not_active Ceased
Patent Citations (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| GB2038030A (en) * | 1978-12-15 | 1980-07-16 | Hewlett Packard Co | Optical beam director |
| GB2041576A (en) * | 1979-02-02 | 1980-09-10 | Leeds & Northrup Co | Electric drive unit control apparatus |
| GB2055487A (en) * | 1979-07-06 | 1981-03-04 | Jaeger | An adder of electrical pulses using an electric motor with position control |
| EP0032312A2 (en) * | 1979-12-31 | 1981-07-22 | Fanuc Ltd. | Control system for stopping spindle at predetermined rotational position |
| GB2116749A (en) * | 1982-03-03 | 1983-09-28 | Perkin Elmer Corp | Pen drive for recorder |
| EP0101051A2 (en) * | 1982-08-17 | 1984-02-22 | Sumitomo Electric Industries Limited | Method of position control by DC servomotor |
Cited By (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| GB2369193A (en) * | 2000-06-21 | 2002-05-22 | Leica Microsystems | Laser scanning microscope and shutter |
| GB2369193B (en) * | 2000-06-21 | 2002-11-06 | Leica Microsystems | Laser scanning microscope and shutter for an optical system |
| DE10029444B4 (en) * | 2000-06-21 | 2004-07-22 | Leica Microsystems Heidelberg Gmbh | Optical arrangement |
| CN108663871A (en) * | 2017-03-31 | 2018-10-16 | 上海微电子装备（集团）股份有限公司 | A kind of shutter device |
| EP3605220A4 (en) * | 2017-03-31 | 2021-01-20 | Shanghai Micro Electronics Equipment (Group) Co., Ltd. | Shutter device |
| US10928704B2 (en) | 2017-03-31 | 2021-02-23 | Shanghai Micro Electronics Equipment (Group) Co., Ltd. | Shutter device |
| CN108663871B (en) * | 2017-03-31 | 2021-06-25 | 上海微电子装备（集团）股份有限公司 | Shutter device |
Also Published As
| Publication number | Publication date |
|---|---|
| GB2151372B (en) | 1987-12-16 |
| DE3441298A1 (en) | 1985-05-23 |
| GB8428372D0 (en) | 1984-12-19 |
| JPS60102737A (en) | 1985-06-06 |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| PE20 | Patent expired after termination of 20 years |
Effective date: 20041108 |