JP5127677B2 - Light source control circuit and direct exposure apparatus - Google Patents

Description

  The present invention relates to a light source control circuit for a light source having a laser diode and a direct exposure apparatus having the light source control circuit.

  In recent years, wiring patterning methods for semiconductors and substrates by direct exposure (maskless exposure) without using a photomask have been proposed. According to this method, correction for coping with expansion / contraction, distortion, displacement, etc. of the substrate to be exposed can be performed in advance at the stage of generating exposure data, or can be performed in real time, thereby improving manufacturing accuracy. The method is superior to the conventional exposure method using a photomask in terms of yield improvement, delivery time reduction, manufacturing cost reduction, and the like.

  As a patterning method by direct exposure, for example, there is a method of forming an exposure pattern by direct exposure processing using a digital micromirror device (DMD) (see, for example, Patent Document 1).

  FIG. 6 is a diagram illustrating a conventional example of a direct exposure apparatus using a DMD. Hereinafter, components having the same reference numerals in different drawings mean components having the same functions.

  In the direct exposure apparatus 100, when directly exposing the photoresist formed on the exposure target substrate 200 that moves relative to the DMD (digital micromirror device) 105, exposure data corresponding to the exposure pattern is generated by the computer 102. This exposure data is input to the DMD 105 in the optical engine 103.

  The single wavelength light generated by the light source 101 is incident on an optical engine (also referred to as “exposure engine”) 103 via a relay optical fiber 104. In the optical engine 103, the light incident from the light source 101 is converted into parallel light by the collimator lens 107-1, and this parallel light is irradiated to the DMD 105 using the reflection mirror 106.

  In the DMD 105, a plurality of tiltable micromirrors (micromirrors) are arranged. The DMD 105 tilts each micromirror according to the exposure data, thereby appropriately changing the direction of the reflected light from each micromirror and generating projection pattern light. The projection pattern light is converted into parallel light by the collimator lens 107-2, the depth of focus is corrected by the objective lens 108, and an image is formed on the photoresist applied on the exposure target substrate 200. The photoresist material is exposed to light when irradiated with a predetermined amount of integrated illuminance, and forms a pattern on the exposure target substrate 200.

  The exposure target substrate 200 is placed on a stage 111 that can move in the X, Y, X, and θ directions. The stage 111 moves in the XY directions (vertical and horizontal directions) in conjunction with the projection pattern. Further, since the depth of focus of the projection pattern varies depending on the thickness of the exposure target substrate 200, the position of the stage 111 is adjusted in the Z direction (height direction) to optimize the depth of focus of the projection pattern with respect to the exposure target substrate 200. . In addition, the rotation angle θ with respect to the Z axis can be adjusted as necessary for posture correction of the exposure target substrate 200.

  In the direct exposure apparatus 100, the light source 101 that irradiates light on the exposure target substrate 200 stabilizes the light output irradiated on the exposure target substrate surface in order to obtain a good exposure effect, and is uniform and uniform depending on the location. It is necessary to make it. For this reason, before starting the exposure process for the exposure target substrate 200, the stage 111 is moved so that the light from the objective lens 108 enters the illuminance meter 110 provided on the stage 111, and the illuminance on the exposure surface is measured. Based on the measurement result, the light source 101 and the optical engine 103 are appropriately adjusted as necessary.

  The light source 101, the optical engine 103, the DMD 105, the illuminance meter 110, and the stage 111 are controlled by the computer 102. Each device may be controlled with a dedicated computer.

Generally, a semiconductor laser diode (hereinafter simply referred to as “laser diode”) is used as the light source 101 for generating light to be applied to the optical engine 103. The wavelength of the laser diode is adjusted to the wavelength of the photoresist material is sensitive to be used for exposure. For example, the wavelength of a blue-violet laser diode is 405 nm.

In order to form a fine and highly accurate wiring pattern at high speed by direct exposure, the light output of the light source and the stability of the illuminance are indispensable. As a method of controlling the light output (light power) of the light source, there are two control methods of auto power control (Auto Power Control: APC) and auto current control (Auto Current Control: ACC).

  Among these, the auto power control is to control the light emission amount of the laser diode based on the output of the photodiode when the light emitted from the laser diode is received. FIG. 7 is a control block diagram of a laser diode based on general auto power control. A photodiode (PD) 212 receives light from the laser diode 211 and outputs a current corresponding to the amount of light emitted. This current is converted into a voltage by the voltage conversion circuit 213, and the output is input to the feedback circuit 214. The feedback circuit 214 controls the amount of current flowing into the laser diode 211 by the controller 215 so that the received light current obtained from the photodiode 212 is always constant. The control unit 216 instructs the controller 215 about the light output amount of the laser diode 211.

  On the other hand, the auto current control is to feedback the current flowing into the laser diode and control the light emission amount of the laser diode. FIG. 8 is a control block diagram of a laser diode based on general auto-current control. The current flowing into the laser diode 211 is detected, converted into a voltage by the voltage conversion circuit 213, and input to the feedback circuit 214. The controller 215 controls the amount of current that flows into the laser diode 211 based on the output of the feedback circuit 214. The control unit 216 instructs the controller 215 about the light output amount of the laser diode 211.

  In the direct exposure apparatus, the light output of the light source is controlled using such auto power control (APC), auto current control (ACC), or a combination thereof.

  As described above, for the light source that irradiates the exposure target substrate with light, in order to obtain a good exposure effect, the light output irradiated on the exposure target substrate surface is stabilized and uniform with no unevenness depending on the location. There is a need to. For this reason, the light source and the optical engine are appropriately calibrated (adjusted) before the exposure process for the exposure target substrate is started.

  FIG. 9 is a diagram for explaining a conventional example of a light source calibration method that is executed before the exposure processing for an exposure target substrate is started. In this calibration method, the illuminance meter 110 is connected to the position of the optical fiber 104 to which the light source 101 is connected at one end, on the side to which the optical engine is connected during the exposure process, and the illuminance of the light from the light source 101 at this position. Measured. The connection position of the illuminance meter 110 is the same even if the light emission control of the laser diode is auto power control (APC) or auto current control (ACC).

  In addition to this calibration method, before starting the exposure process on the exposure target substrate, the illuminance distribution of light on the exposure surface corresponding to the exposure target substrate is measured in advance, and the measurement result is fed back to the adjustment of the illuminance of the light source. There is a method (see, for example, Patent Document 2).

JP-A-10-112579 JP 2006-186291 A

  The conventional calibration method shown in FIG. 9 has several drawbacks. First, the position where the illuminance meter 110 is installed is a position where the optical engine is connected during the exposure process, and is not the exposure surface of the exposure object. In the direct exposure apparatus, the stability of light illuminance is required only for the exposure surface of the exposure object. Even if the light output of the light source is stable at the connection portion between the optical fiber 104 and the optical engine, that is, the light input portion to the optical engine, the light output passes through the optical engine and reaches the exposure surface of the exposure target substrate. Until, it is not always stable.

  On the other hand, a method of calibrating the light output of a light source by measuring the illuminance of an exposure surface of an exposure object that requires stability of light illuminance using an illuminometer has been conventionally performed. However, in any of the above calibration methods, the operator adjusts the light source after recalculating the necessary light output value based on the illuminance measurement value. That is, since this operation involves manual operation by the operator, the work efficiency is low and human error is likely to occur.

In addition, the above Patent Document 2 (Japanese Patent Application Laid-Open No. 2006-186291) specifically describes a specific method for feeding back the measurement result of the illuminance distribution of light measured on the exposure surface corresponding to the exposure target substrate to the illuminance of the light source. Not shown. In a direct exposure apparatus, a light source and a main body composed of an optical engine and a stage are usually installed at a distance of several meters. When feedback data is transmitted, for example, by electrical wiring using electric wires for the physical distance generated between the stage on which the exposure target substrate is placed and the light source, due to such a long wiring length, parasitic capacitance and inductance components Impedance mismatching of the transmission path occurs, signal integrity (signal integrity) is lost, and data is not transmitted correctly. In addition, an electrical wiring having a long wiring length acts as an antenna, and therefore, electromagnetic interference (EMI) in which extraneous noise is superimposed on transmission data due to reception of unnecessary radiation radiated from other devices may occur. . In addition, each device in the direct exposure apparatus is connected by a large number of electrical wirings, and a plurality of optical engines are provided, so that the wiring can be more complicated. Such a large and complicated electrical wiring induces a decrease in maintainability and a connection mistake.

  Accordingly, an object of the present invention is to provide a light source control circuit capable of automatically calibrating the light output of a light source and having a simple structure, and a direct exposure apparatus having the light source control circuit. .

  In order to achieve the above object, in the present invention, a light source control circuit for a light source having a laser diode receives a light emitted from the laser diode and outputs a photocurrent proportional to the power of the light. The acquisition means for acquiring the current value of the photocurrent output from the photodiode when the acquisition instruction is received, the conversion means for converting the current value into the first voltage value, and the rewrite instruction for the first voltage value. The latch means for holding the second voltage value until the first voltage value is received, the drive means for supplying a drive current corresponding to the second voltage value to the laser diode, and the first voltage value and the second voltage value are compared. When the comparison means determines that the first voltage value and the second voltage value do not match, the comparison means transmits an instruction to acquire the current value to the acquisition means, and instructs the latch means to rewrite the stored contents. It includes a signal controlling means.

  Further, the light source control circuit according to the present invention is preferably a wireless transmission unit that wirelessly transmits data relating to the first voltage value generated by the conversion unit, and a wireless reception unit that receives the data wirelessly transmitted by the wireless transmission unit. The latch means holds the first voltage value received by the wireless reception means as the second voltage value until a rewrite instruction is received.

  The light source control circuit can be applied to directly control the light source of the exposure apparatus. That is, according to the present invention, a direct exposure apparatus that directly draws an exposure pattern on an exposure target substrate by irradiating light on the exposure target substrate includes: a light source having a plurality of laser diodes; A circuit, and an optical engine that reflects light emitted from a laser diode in the light source toward an exposure target substrate in accordance with exposure data defining an exposure pattern.

  According to the present invention, the light output of the light source can be automatically calibrated. In addition, the light source control circuit according to the present invention can be applied to directly control the light source of the exposure apparatus, so that the light irradiated onto the exposure target substrate surface can be controlled to a desired illuminance distribution.

  In addition, according to the present invention, since wireless communication is used for data communication, signal integrity (signal integrity) can be ensured unlike wired communication, and electromagnetic interference (EMI) does not occur. Since there are few electric wirings, the structure of the light source control circuit and the direct exposure apparatus having the light source control circuit can be simplified. Accordingly, it is possible to suppress a decrease in maintainability and to prevent a connection mistake.

  FIG. 1 is a principle block diagram of a light source control circuit according to the present invention. A light source control circuit 1 for a light source having a laser diode 2 receives a light emitted from the laser diode 2 and outputs a photocurrent proportional to the power of the light (amount of light such as illuminance). When the instruction is received, the acquisition unit 11 that acquires the current value of the photocurrent output from the photodiode 3, the conversion unit 12 that converts the current value into the first voltage value, and the first voltage value are rewritten. Latch means 13 that holds the second voltage value until receiving an instruction; drive means 14 that supplies a drive current corresponding to the second voltage value to the laser diode 2; first voltage value and second voltage When the comparison means 15 determines that the first voltage value and the second voltage value do not match, the comparison means 15 that compares the values with each other transmits a current value acquisition instruction to the acquisition means 11 and the latch means Keep to 13 And a control unit 16 for transmitting a rewrite instruction of the contents, the.

  Next, a direct exposure apparatus including the light source control circuit will be described as an embodiment of the present invention. FIG. 2 is a block diagram of a direct exposure apparatus according to an embodiment of the present invention.

  According to the embodiment of the present invention, the direct exposure apparatus 10 that directly draws an exposure pattern on the exposure target substrate 200 by irradiating the exposure target substrate 200 with light includes a plurality of laser diodes and light emitted by the laser diodes. A light source 101 including a photodiode that receives light and outputs a photocurrent proportional to the power of the light, a light source control circuit including a light amount measuring device 21 and an LD light emission control circuit 22, and a laser diode in the light source 101. And an optical engine 103 that reflects emitted light toward an exposure target substrate in accordance with exposure data that defines an exposure pattern.

  In the direct exposure apparatus 10, exposure data corresponding to an exposure pattern to be formed on the exposure target substrate 200 that moves relative to the DMD (digital micromirror device) 105 is input to the DMD 105 in the optical engine 103.

  The single wavelength light generated by the light source 101 enters the optical engine 103 via the relay optical fiber 104. In the optical engine 103, the light incident from the light source 101 is converted into parallel light by the collimator lens 107-1, and this parallel light is irradiated to the DMD 105 using the reflection mirror 106.

  In the DMD 105, a plurality of tiltable micromirrors (micromirrors) are arranged. The DMD 105 tilts each micromirror according to the input exposure data, thereby appropriately changing the direction of the reflected light from each micromirror and generating projection pattern light. The projection pattern light is converted into parallel light by the collimator lens 107-2, the depth of focus is corrected by the objective lens 108, and an image is formed on the photoresist applied on the exposure target substrate 200. The photoresist material is exposed to light when irradiated with a predetermined amount of integrated illuminance, and forms a pattern on the exposure target substrate 200.

The exposure target substrate 200 is placed on a stage 111 that can move in the X, Y, X, and θ directions. The stage 111 moves in the XY directions (vertical and horizontal directions) in conjunction with the projection pattern. In addition, the position of the stage 111 is adjusted in the Z direction (height direction) to optimize the depth of focus of the projection pattern with respect to the exposure target substrate 200. In addition, the rotation angle θ with respect to the Z axis can be adjusted as necessary for posture correction of the exposure target substrate 200. The light quantity measuring device 21 is provided in the peripheral portion of the stage 111, but only the sensor part (light quantity measuring slit 31 and photodiode 3 ) of the light quantity measuring device 21 is provided on the stage 111, and the other parts are the stage 111. You may provide in other parts and parts other than the stage 111.

  In order to make the light irradiated onto the surface of the exposure target substrate 200 uniform with no unevenness depending on the location, the light that has passed through the objective lens 108 is measured before the exposure process for the exposure target substrate 200 is started. The stage 111 is moved so as to enter the light source, the laser diode in the light source 101 is turned on, and the light source control circuit according to the embodiment of the present invention is operated, thereby realizing automatic calibration of the light emission amount of the light source 101. FIG. 2 shows a case where the light quantity measuring device 21 provided on the stage 111 is moved to a position immediately below the objective lens 108. After the light source control circuit according to the embodiment of the present invention is operated to calibrate the light emission amount of the light source 101, the stage 111 is moved so that the light transmitted through the objective lens 108 enters the exposure target substrate 200, and exposure processing is performed. Execute.

  Next, the configuration of the light quantity measuring device 21 and the LD light emission control circuit 22 constituting the light source control circuit in the embodiment of the present invention will be described with reference to FIGS. FIG. 3 is a block diagram showing the configuration of the light quantity measuring device in the light source control circuit according to the embodiment of the present invention. FIG. 4 is a block diagram showing the configuration of the LD light emission control circuit in the light source control circuit according to the embodiment of the present invention.

  In the light quantity measuring device 21 shown in FIG. 3, the light output from the optical engine is received by the photodiode 3 through the light quantity measurement slit 31. When the photodiode 3 receives light, it outputs a photocurrent (monitor current) proportional to the power of the light (light quantity such as illuminance). Since the light receiving surface of the photodiode 3 is provided at a position (height) corresponding to the exposure surface of the exposure target substrate, the light power received by the photodiode 3 is the light power on the exposure surface of the exposure target substrate. . The light quantity measurement slit 31 is provided with an opening having a predetermined opening area.

  This photocurrent is acquired when an acquisition instruction is received from the controller 41 in the LD light emission control circuit 22 shown in FIG. 4 to be described later via wireless communication between the wireless module 42 and the wireless module 34.

  The current-voltage conversion circuit 32 converts the current value Im of the photocurrent into a voltage value Va (Im). At this stage, the voltage value Va (Im) is an analog value. The A / D converter 33 converts the analog voltage value Va (Im) into a digital voltage value V (Im). In the embodiment of the present invention, the A / D converter 33 is constituted by a microcomputer 35. The microcomputer 35 also performs communication protocol control with the wireless module 34 and the computer 37. Instead of the microcomputer 35, a PLD (Programmable Logic Circuit) such as an FPGA (Field Programmable Gate Array) may be used. In this case, the A / D converter 33 is not included in the PLD. Will be.

  In the microcomputer 35, the optical output and illuminance are calculated using the digital voltage value V (Im) generated by the A / D converter 33 (reference numeral 36). May be used for other purposes.

  Data relating to the digital voltage value V (Im) is transmitted to the wireless module 42 of FIG. 4 by wireless communication of the wireless module 34. There is no particular limitation on the standard of wireless communication between the wireless module 34 in the light quantity measuring device 21 shown in FIG. 3 and the wireless module 42 in the LD light emission control circuit 22 shown in FIG. For example, it may be realized by a wireless LAN, but it is sufficient if mutual communication is possible within a limited space around the direct exposure apparatus. For example, it may be called a wireless network WPAN (Wireless Personal Area Network) having a narrow communication range (several meters to several tens of meters), such as IEEE 802.15.1 (Bluetooth (registered trademark)), IEEE 802.15. 3a (UWB), IEEE 802.15.4 (ZigBee (registered trademark)), and the like. As described above, in the embodiment of the present invention, communication is performed wirelessly instead of wired, so the structure of the LD light emission control circuit 22 can be said to be easy.

  When the controller 41 in the LD light emission control circuit 22 shown in FIG. 4 transmits an acquisition instruction to the wireless module 34 in the light quantity measuring device 21 shown in FIG. 3 through the wireless module 41, the wireless module 42 then sends a voltage value from the wireless module 34. Data regarding V (Im) is received.

  The voltage value V (Im) received by the wireless module 42 is input to the comparison operation circuit 44 and the latch circuit 43. In the latch circuit 43, the held content is retained until an instruction to rewrite the retained content is received from the controller 41. The voltage value V (Im) that is In this specification, for convenience, the voltage value received by the wireless module 42 and input to the comparison operation circuit 44 is V (Im) 1, and the voltage value held by the latch circuit 43 and input to the comparison operation circuit 44 is It is described as V (Im) 2. That is, the voltage value V (Im) 1 is a value newly acquired after the voltage value V (Im) 2.

  The comparison operation circuit 44 compares the voltage value V (Im) 1 received by the wireless module 42 with the voltage value V (Im) 2 held by the latch circuit 43.

  When the comparison calculation circuit 44 determines that the voltage value V (Im) 2 and the voltage value V (Im) 1 do not match, the controller 41 passes through the wireless module 42 and the wireless module 34 in the light quantity measuring device 21 shown in FIG. An acquisition instruction is transmitted to the latch circuit 43, and an instruction to rewrite the retained content is transmitted to the latch circuit 43. That is, the newly acquired voltage value V (Im) 1 is held in the latch circuit 43 as the voltage value V (Im) 2.

  The LD light emission control circuit 22 includes a known auto power control type drive circuit as follows. That is, the D / A converter 45 converts the digital voltage value V (Im) 2 held in the latch circuit into an analog voltage value Va (Im) 1. The gain adjustment circuit 46 adjusts the voltage value by applying an appropriate gain (voltage amplification factor) to the voltage value Va (Im) 1. This voltage value is converted into a current value Im by a voltage-current conversion circuit 47. The current value Im is duplicated by the current mirror circuit 48 and is passed through the variable resistor Rp as a constant current. Due to this variable resistance Rp, the voltage Vm is generated according to Ohm's law. The comparison operation circuit 49 compares the voltage Vm with the reference voltage Vref, and the LD light emission drive circuit 50 controls the drive current Iop of the current source 51 so that the voltage Vm matches the reference voltage Vref. When the drive current Iop flows into the laser diode 2, the laser diode 2 emits light with a light emission amount corresponding to the magnitude of the drive current Iop.

  The latch circuit 43, the comparison operation circuit 44, and the controller 41 in the LD light emission control circuit 22 can be configured by a microcomputer or a PLD (Programmable Logic Device). In the case of a microcomputer, the D / A converter 45 can be included in this configuration. Of course, the latch circuit 43, the comparison operation circuit 44, the controller 41, and the D / A converter 45 may be configured as separate elements.

  Next, the operation of the light source control circuit in the embodiment of the present invention will be described with reference to FIG. FIG. 5 is a flowchart showing an operation flow of the light source control circuit according to the embodiment of the present invention. First, as initial operation S100, each process of steps S101 to S106 is executed.

  In step S101, the controller 41 in the LD light emission control circuit 22 controls the LD light emission drive circuit 50 to start light emission of the laser diode 2. At this time, the light emission amount may be an appropriate amount. At this time, no voltage value is held in the latch circuit 43 yet.

  Next, in step S <b> 102, the controller 41 transmits an acquisition instruction to the wireless module 34 in the light amount measuring device 21 through the wireless module 42. When the microcomputer 37 in the light quantity measuring device 21 receives this acquisition instruction through the wireless module 34, in step S103, the microcomputer 37 acquires the current value Im of the photocurrent proportional to the power of the light received by the photodiode 3, and the current − The voltage conversion circuit 32 converts it into a voltage value Va (Im), and the A / D converter 33 converts it into a digital voltage value V (Im). Data about the acquired digital voltage value V (Im) 1 is transmitted to the wireless module 42 in the LD light emission control circuit by wireless communication of the wireless module 34.

  Next, in step S104, the latch circuit 43 holds the voltage value V (Im) 1 received by the wireless module 42. The latch circuit 43 continues to hold the held content until it receives an instruction to rewrite the held content from the controller 41.

  Next, in step S105, the digital voltage value V (Im) 2 held in the latch circuit 43 is output to the D / A converter 45. Next, in step S106, the voltage value V (Im) 2 is output. Then, control of a known auto power control system is executed.

  Next, in step S <b> 107, the controller 41 transmits an acquisition instruction to the wireless module 34 in the light quantity measuring device 21 through the wireless module 42.

  When receiving the acquisition instruction through the wireless module 34, the microcomputer 35 in the light quantity measuring device 21 acquires the current value Im of the photocurrent proportional to the power of the light received by the photodiode 3 in step S108, and the current-voltage The voltage is converted into a voltage value Va (Im) by the conversion circuit 32, and is converted into a digital voltage value V (Im) by the A / D converter 33. Data relating to the digital voltage value V (Im) is transmitted to the wireless module 42 in the LD light emission control circuit by wireless communication of the wireless module 34.

  Next, in step S109, the comparison operation circuit 44 compares the voltage value V (Im) 1 received by the wireless module 42 with the voltage value V (Im) 2 held by the latch circuit 43.

  When the comparison calculation circuit 44 determines in step S109 that the voltage value V (Im) 2 and the voltage value V (Im) 1 do not match, the process proceeds to step S110. In step S <b> 110, the controller 41 transmits a retention content rewrite instruction to the latch circuit 43. As a result, the latch circuit 43 rewrites the contents already held, and newly holds the voltage value V (Im) 1 received by the wireless module 42 as the voltage value V (Im) 2.

  Next, in step S111, the digital voltage value V (Im) 2 held in the latch circuit 43 is output to the D / A converter 45, and then in step S112, with respect to the voltage value V (Im), Control of a known auto power control method is executed.

  The series of processing of steps S110, S112, S112, S107, S108, and S109 is repeated until the comparison operation circuit 44 determines in step S109 that the voltage value V (Im) 2 and the voltage value V (Im) 1 match. Will be executed.

  On the other hand, when the comparison calculation circuit 44 determines in step S109 that the voltage value V (Im) 2 and the voltage value V (Im) 1 match, the process proceeds to step S113. In step S113, the digital voltage value V (Im) 2 held in the latch circuit 43 at that time is output to the D / A converter 45, and then in step S114, the voltage value V (Im) 2 is set. On the other hand, control of a known auto power control system is executed. That is, in this case, since the light emission of the light source can be stabilized to a desired light emission amount, the contents held in the latch circuit 43 are not rewritten, and the digital data held in the latch circuit 43 at that time is not rewritten. Based on the voltage value V (Im) 2, the control of the known auto power control method is executed. Thus, the automatic calibration of the light emission amount of the light source 101 by the light source control circuit according to the embodiment of the present invention is completed.

  After the light source control circuit according to the embodiment of the present invention is operated and the light emission amount of the light source 101 is calibrated, the irradiation light at the position (height) corresponding to the substrate surface of the exposure target substrate 200 is stabilized depending on the location. Therefore, the stage 111 is moved so that the light transmitted through the objective lens 108 shown in FIG. 2 is incident on the exposure target substrate 200, and the exposure process is executed. It should be noted that the automatic calibration of the light emission amount of the light source 101 by the light source control circuit according to the embodiment of the present invention may be executed as necessary, and is executed for each exposure process or when the product reaches a certain number of lots. Just do it.

  INDUSTRIAL APPLICABILITY The present invention can be used for calibrating the light emission amount of a light source including a laser diode and a photodiode that receives light emitted from the laser diode and is arranged to control the light emission intensity of the laser diode.

  The present invention is very effective particularly when a large number of laser diodes are used as the light source of the direct exposure apparatus. In such a direct exposure apparatus, a surface light source for irradiating light on an exposure target is configured by arranging a plurality of light sources. According to the direct exposure apparatus, correction for dealing with expansion / contraction, distortion, displacement, etc. of the exposure object (exposure target substrate) can be performed in advance at the stage of generating the exposure data, or can be performed in real time. Therefore, advantages such as improved manufacturing accuracy, improved yield, shorter delivery time, and reduced manufacturing cost are brought about.

It is a principle block diagram of the light source control circuit by this invention. It is a block diagram of the direct exposure apparatus by the Example of this invention. It is a block diagram which shows the structure of the light quantity measuring device in the light source control circuit by the Example of this invention. It is a block diagram which shows the structure of the LD light emission control circuit in the light source control circuit by the Example of this invention. 4 is a flowchart illustrating an operation flow of a light source control circuit according to an embodiment of the present invention. It is a figure which illustrates one prior art example of the direct exposure apparatus using DMD. It is a control block diagram of a laser diode based on general auto power control. It is a control block diagram of a laser diode based on general auto-current control. It is a figure explaining one prior art example of the calibration method of the light source performed before starting the exposure process with respect to an exposure object board | substrate.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Light source control circuit 2 Laser diode 3 Photodiode 10 Direct exposure apparatus 11 Acquisition means 12 Conversion means 13 Latch means 14 Drive means 15 Comparison means 16 Control means 21 Light quantity measuring device 22 LD light emission control circuit 31 Light quantity measurement slit 32 Current-voltage conversion Circuit 33 A / D converter 34 Wireless module 35 Microcomputer 36 Light output and illuminance calculation block 37 Computer 41 Controller 42 Wireless module 43 Latch circuit 44 Comparison operation circuit 45 D / A converter 46 Gain adjustment circuit 47 Voltage-current conversion circuit 48 Current mirror circuit 49 Comparison operation circuit 50 LD light emission drive circuit 51 Constant current source 101 Light source 103 Optical engine 104 Optical fiber 105 DMD
106 Reflecting mirrors 107-1, 107-2 Collimating lens 108 Objective lens 110 Illuminance meter 111 Stage 200 Exposure target substrate

Claims (4)

A light source control circuit for a light source having a laser diode,
A photodiode that receives light emitted by the laser diode and outputs a photocurrent proportional to the power of the light;
An acquisition means for acquiring a current value of the photocurrent output from the photodiode when an acquisition instruction is received;
Conversion means for converting the current value into a first voltage value;
Latch means for holding the first voltage value as a second voltage value until a rewrite instruction is received;
Driving means for supplying a driving current corresponding to the second voltage value to the laser diode;
Comparing means for comparing the first voltage value and the second voltage value;
When the comparison means determines that the first voltage value and the second voltage value do not match, the current value acquisition instruction is transmitted to the acquisition means, and the retention content rewrite instruction to the latch means Control means for transmitting
A light source control circuit comprising: Wireless transmission means for wirelessly transmitting data relating to the first voltage value generated by the conversion means;
Wireless receiving means for receiving the data wirelessly transmitted by the wireless transmitting means;
Further comprising
The light source control circuit according to claim 1, wherein the latch unit holds the first voltage value received by the wireless reception unit as a second voltage value until the rewrite instruction is received.   The light source control circuit according to claim 1, wherein the latch unit, the comparison unit, and the control unit are configured by a microcomputer or a PLD. A direct exposure apparatus that directly draws an exposure pattern on the exposure target substrate by irradiating the exposure target substrate with light,
A light source having a plurality of laser diodes;
The light source control circuit according to any one of claims 1 to 3,
An optical engine that irradiates light emitted by the laser diode in the light source toward the substrate to be exposed according to exposure data defining the exposure pattern;
A direct exposure apparatus comprising:

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