TWI815773B - Lighting method for lamp - Google Patents

Abstract

The invention provides a method for lighting a lamp which is possible to reduce useless power in contribution for exposing an exposure target, and capable of achievement of prolonging the life of a lamp. An exposure power is supplied to a lamp at exposure time for exposing an exposure object X, and a standby power is supplied to the lamp at the time other than the exposure time, wherein the standby power is lower than the exposure power and can keep the lamp being remained in a lighting state.

Description

How to light a lamp

The present invention relates to a method of lighting a lamp that can emit light used for, for example, exposing a printed wiring board or the like.

A conventionally used printed wiring board is a wiring pattern formed with a metal such as copper on a substrate made of resin or glass epoxy resin in order to actually mount components on electronic equipment. The wiring pattern on the printed wiring substrate may be formed using a photolithography technique. Photolithography is a method of applying a photoresist of a photosensitive agent to the entire surface of a substrate on which a metal layer serving as wiring is formed, and irradiating light from an exposure device to pass through the same wiring pattern. This is done using a photo mask.

Photoresists include a negative photoresist in which the solubility of the photoresist is reduced by irradiation with light, and a positive photoresist in which the solubility of the photoresist is increased by irradiation of light. When the photoresist portion whose solubility is relatively increased by irradiation of light is removed by chemical treatment, and the exposed metal layer is removed by etching, only the metal layer remains under the portion where the photoresist remains. photoresist to form a wiring pattern on the substrate. Even when irradiation light is irradiated on either a positive or negative photoresist, in order to ensure uniform exposure over the entire irradiation surface, multiple discharge lamps with an average luminous intensity of one lamp can be used. light source.

The discharge lamp generates ultraviolet light by causing an arc discharge to occur between a pair of electrodes that are separated from each other and arranged oppositely in an airtight internal space of the luminous tube, thereby exciting the mercury enclosed in the internal space to generate ultraviolet light.

The most appropriate exposure time is determined according to the type of photoresist; that is, the length of time that the light from the discharge lamp is irradiated onto the photoresist is determined. Therefore, a shutter is placed between the discharge lamp and the exposure object (photoresist, etc.), and by opening the shutter only at the required time, the general implementation method is to expose the exposure object with the most appropriate exposure time. The shutter is closed during other periods (for example, when changing the exposure object, etc.). (For example, Patent Document 1). "Advanced Technical Documents" "Patent Document"

"Patent Document 1" Japanese Patent Application Publication No. 2002-373840

"Problems to be solved by inventions"

However, conventional exposure methods are problematic. Because the exposure time is controlled by the shutter, the lamp still needs to continue to emit light even if no exposure is performed. This not only causes the power to be ineffective, but also often emit light at the rated power, making it impossible to achieve a long service life of the lamp.

The present invention was made in view of such problems, and its object is to provide a method for lighting a discharge lamp that can reduce useless electric power that does not contribute to the exposure of an exposure object and can achieve a long service life of the lamp. change. "Methods used to solve problems"

According to one aspect of the present invention, a method for lighting a lamp is provided, wherein During the exposure time for exposing the exposure object, exposure power is supplied to the lamp, In addition to the exposure time, standby power is supplied to the lamp. The standby power is lower than the exposure power and can maintain the lighting state of the lamp.

Preferably, the lamp is a discharge lamp, and the supply time of the exposure power is a period between the internal pressure of the discharge lamp and the constant internal pressure of the discharge lamp when the exposure power is continuously supplied to the discharge lamp. The time is even shorter.

Preferably, the lamp is an LED (light-emitting diode); the supply time of the exposure power is: when the contact temperature of the LED reaches the point where the exposure power is continuously supplied to the LED, the constant contact time of the LED is The time to set the temperature is even shorter.

Preferably, when the lamp is an LED, power supply to the lamp is stopped outside the exposure time to turn off the lamp.

Preferably, the irradiation intensity from the lamp is changed during the exposure time in accordance with the light sensitivity of the exposed photoresist. "Invention Effect"

According to the present invention, it is possible to provide a method for lighting a lamp that can reduce useless electric power that does not contribute to the exposure of an exposure object and can extend the service life of the lamp.

(Example 1)

(Construction of exposure machine 10) FIG. 1 shows an exposure machine 10 according to Embodiment 1 to which the present invention is applicable. The exposure machine 10 is roughly composed of an exposure device 50 , an integrator 12 , a concave mirror 14 , an irradiation surface 16 , and a shutter 24 .

The exposure device 50 emits light containing a wavelength suitable for exposure of the object X to be exposed. The details of the exposure device 50 will be described after describing the structure of the exposure machine 10 .

The integrator 12 has an incident surface 18 that receives light from the exposure device 50 and an exit surface 20 that improves the uniformity of the received light and emits the light. A plurality of flying eye lenses 21 are formed on the entrance surface 18 and the exit surface 20 respectively.

The concave mirror 14 has a reflective concave surface 22 on its inner side. The concave mirror 14 uses the reflective concave surface 22 to reflect the light emitted from the integrator 12 into parallel light.

The irradiation surface 16 receives parallel light from the concave mirror 14 and is arranged in a direction approximately perpendicular to the parallel light. The exposure target object X is placed on the irradiation surface 16 . For example, a photosensitive agent or a photoresist is applied to the surface of the object X to be exposed. By irradiating parallel light from the concave mirror 14 to a desired area of the exposure object X, a desired circuit pattern or the like is formed on the surface of the exposure object X.

The shutter 24 is disposed on the exit surface 20 side of the manifold 12 and is a device for opening and closing the path (light path) of the light from the discharge lamp 110 . The shutter 24 is opened in accordance with the exposure time of the exposure object X to allow the light from the discharge lamp 110 to reach the exposure object The irradiation surface 16. In addition, the position where the shutter 24 is disposed is of course not limited to this embodiment, and may be disposed at other positions on the optical path between the self-discharge lamp 110 and the exposure target object X.

(Structure of exposure device 50) FIG. 2 is a diagram showing the exposure device 50 according to Embodiment 1 to which the present invention is applied. In addition, FIG. 3 is a plan view of the exposure device 50. The exposure device 50 includes a plurality of light source devices 100, a frame 52, a discharge lamp switch 53, a discharge lamp power supply 54, and a control unit 60.

The light source device 100 emits light having a wavelength suitable for exposure of the exposure object X. The light source device 100 is roughly composed of a discharge lamp 110, a reflector 150, and an insulating base 170, as shown in FIG. 4 . In addition, the mirror 150 and the insulating base 170 may be collectively described as the mirror container 151 .

As shown in FIG. 5 , the discharge lamp 110 has an arc tube portion 112 and a pair of sealing portions 114 extending from the arc tube portion 112 . The arc tube part 112 and the pair of sealing parts 114 are integrally formed of quartz glass. Furthermore, an internal space 116 sealed by the sealing portion 114 is further formed in the arc tube portion 112 .

Each sealing part 114 of the discharge lamp 110 is provided with: an embedded molybdenum foil 118, and a tungsten foil with one end connected to one end of the foil 118 and the other end disposed in the internal space 116. A pair of electrodes 120 and a pair of lead rods 122 having one end connected to the other end of the foil 118 and the other end extending outward from the sealing portion 114 . In addition, the internal space 116 is filled with a specified amount of mercury 124 and halogen (for example, bromine).

When a predetermined high voltage is applied to the pair of lead bars 122 provided in the discharge lamp 110, the glow discharge started between the pair of electrodes 120 provided in the internal space 116 of the arc tube portion 112 moves to arc discharge. The evaporated and excited mercury 124 caused by the arc emits light (mainly ultraviolet light).

Returning to FIG. 4 , in this embodiment, the sealing portion 114 on one side of the light source device 100 is inserted into the sealing portion insertion hole 156 of the reflector 150 . In addition, the discharge lamp 110 may be for AC lighting or DC lighting.

The reflecting mirror 150 has a bowl-shaped reflecting surface 152 on its inner surface. The reflective surface 152 is used to reflect part of the light from the discharge lamp 110 , and the discharge lamp is arranged so that the arc tube portion 112 is located inside the reflector 150 . In this embodiment, the reflective surface 152 defines a paraboloid of revolution. In addition, the luminous point in the discharge lamp 110 (roughly the center position of the arc formed between a pair of electrodes 120 in the internal space 116) is consistent with the focus of the rotating paraboloid. Thereby, the light emitted by the light emitting point of the discharge lamp 110 and reflected by the reflecting surface 152 and emitted from the opening 154 of the reflecting mirror 150 becomes almost parallel light. Of course, the shape of the reflective surface 152 is not limited to this, and may be an ellipsoid of revolution or other surfaces of revolution; or it may be a shape other than a surface of revolution. Furthermore, it is not necessary to align the light-emitting point with the focus; the light-emitting point may be slightly deviated from the focus as needed.

In addition, the opening 154 in the reflector 150 is protrudingly provided with a bottom neck portion 155 starting from the opposite side. In addition, a sealing portion insertion hole 156 into which the sealing portion 114 of one side of the discharge lamp 110 is inserted is formed on the reflecting surface 152 of the reflecting mirror 150 . The sealing portion insertion hole 156 is formed from the bottom of the reflective surface 152 toward the front end of the bottom neck portion 155 .

As shown in FIG. 1 , by combining the reflector 150 with the discharge lamp 110 , the light emitted by the self-discharge lamp 110 travels along the central axis CL of the reflective surface 152 at a specified angle (opening). Angle) and move toward the front of the reflector 150.

Returning to FIG. 4 , the insulating base 170 is made of an electrical insulator such as ceramic, and is formed with a bottom neck portion 155 for the reflector 150 and a discharge lamp 110 inserted into the sealing portion insertion hole 156 . One side of the sealing portion 114 is inserted into the mirror insertion hole 172 . By inserting the bottom portion 155 and the sealing portion 114 into the mirror insertion hole 172, the insulating base 170 covers the sealing portion insertion hole 156 from the outside.

In addition, the insulating base 170 is formed with an inner space 174 connected to the above-mentioned mirror insertion hole 172; in addition, the inner space 174 is connected with the outside, and is formed with a power cord insertion hole through which the power cord A can be inserted. Point 176.

In addition, the insulating base 170 and the discharge lamp 110 are fixed to each other by an inorganic adhesive C having electrical insulation and high thermal conductivity. To explain specifically, the end of the bottom portion 155 of the reflector 150 and the sealing portion 114 on one side of the discharge lamp 110 are inserted into the reflector insertion hole 172 of the insulating base 170; in addition, when the power cord A is disposed on In the state of the inner space 174 of the insulating base 170 , the inorganic adhesive C is filled in the inner space 174 .

Returning to FIG. 3 , the frame 52 is a roughly rectangular parallelepiped-shaped component material that can be used to form a plurality of recesses 58 for installing a plurality of light source devices 100 .

Returning to FIG. 2 , the discharge lamp power supply 54 is the power required for the discharge lamp 110 of each light source device 100 mounted on the frame 52 . In addition, the discharge lamp switch 53 is used to turn on or off the current supplied to the discharge lamp 110 .

The control unit 60 has a control function for operating the discharge lamp power supply 54 and controlling the electric power supplied from the discharge lamp power supply 54 to the discharge lamp 110 . Specifically, as shown in FIG. 6 , when the discharge lamp power supply 54 exposes the exposure object X, the control unit 60 supplies the exposure power H (for example, discharge Rated power of lamp 110). Moreover, control is performed so that standby power L which is lower than the exposure power H and can maintain the lighting state of the discharge lamp 110 is supplied to the discharge lamp 110 outside the above-mentioned exposure time.

In addition, although FIG. 6 illustrates an example in which the discharge lamp power supply 54 supplies the exposure power H in a pulse wave shape, the waveform of the exposure power H supplied to the discharge lamp power supply 54 is of course not limited to this. The power may be increased and decreased in a linear function type (linear type) from the standby power L to the exposure power H as shown in FIG. 7 , or may be increased and decreased in a quadratic function type (parabolic linear type) not shown in the figure. Reduce. Furthermore, for example, as shown in FIG. 8 , the value of the exposure power H during the exposure time may not be a constant value. As shown in Figure 8, even if a relatively high exposure power is supplied in the first half of the exposure time and a relatively low exposure power is supplied in the second half of the exposure time, the amount of power supplied during the exposure time (power time The value obtained by integrating) is the same as the pattern in Figure 6 or Figure 7. Alternatively, the luminous intensity of the discharge lamp 110 may be changed by changing the power supplied to the discharge lamp 110 during the exposure time as shown in FIGS. 9 and 10 according to the characteristics of the exposure target object

In this way, by changing the power supplied to the discharge lamp 110 during the exposure time, the power can be adjusted in a short time according to the reaction degree of the photoresist, and the amount of light suitable for the photoreaction of the photoresist can be supplied.

(Operation of exposure device 50) When the power switch (not shown) of the exposure device 50 is turned on, the discharge lamp switch 53 is turned on, and power supply from the discharge lamp power supply 54 to the discharge lamp 110 of the light source device 100 is started. When power supply starts, the discharge lamp 110 is lit. In addition, at this stage, the power supplied to the discharge lamp 110 from the discharge lamp power supply 54 is the standby power L.

Then, the exposure operation for the exposure object X is started. When the exposure object 110 supplies exposure power H which is higher than the starting power. At the same time, the shutter 24 of the exposure machine 10 is opened, and the exposure light from the discharge lamp 110 is irradiated onto the exposure object X to perform the exposure operation.

When the designated exposure time is reached, the shutter 24 is closed and the power supplied to the discharge lamp 110 from the discharge lamp power supply 54 returns from the exposure power H to the standby power L. After that, the exposure object X whose exposure has been terminated is replaced with an unexposed exposure object X, and then the above-mentioned exposure operation is performed. Thereafter, this exposure operation is repeated.

(Features of Exposure Device 50) According to this embodiment, when the shutter 24 is closed without exposing the exposure object X, the self-discharge lamp power supply 54 supplies the standby power L to the discharge lamp 110; when the shutter 24 is opened and the exposure object X is exposed, The self-discharge lamp power supply 54 supplies the exposure power H higher than the standby power L to the discharge lamp 110 .

Thereby, when the shutter 24 is closed so that the light of the self-discharge lamp 110 does not contribute to the exposure of the exposure object X, relatively low standby power L is supplied to the discharge lamp 110 , so useless power can be reduced.

In addition, compared with the conventional method of constantly lighting the discharge lamp 110 with the rated power, the time for lighting the discharge lamp 110 with the standby power L which is lower than the rated power becomes longer, so the discharge lamp can be achieved 110 long service life.

In addition, when paying attention to the pressure in the internal space 116 of the arc tube portion 112 of the discharge lamp 110 during lighting, in the case of a conventional method of constantly lighting the discharge lamp 110 with rated power, as shown in FIG. 11 , The electric power supplied to the discharge lamp 110 and the pressure of the internal space 116 are almost constant. In contrast, in the lighting method of the discharge lamp 110 of this embodiment, as shown in FIG. 12 , the pressure of the internal space 116 is relatively low when the standby power L is supplied; when the supply of the exposure power H starts , the pressure begins to rise. When the self-exposure power H returns to the standby power L, the pressure that started to rise becomes the maximum and starts to fall. In the future, repeat this type of action.

According to the lighting method of the discharge lamp 110 of this embodiment, the exposure power H is supplied for a period of time that is longer than the time when the internal pressure of the discharge lamp 110 (the pressure of the internal space 116 in the luminous tube portion 112 ) reaches the level of the exposure power H. When the discharge lamp 110 is supplied with the constant internal pressure of the discharge lamp 110 (that is, a pressure state such as that illustrated in FIG. 8 ), the time is even shorter. Therefore, even if the exposure power H when performing the exposure operation of the exposure object The peak pressure of 116 can be suppressed to remain lower than with conventional methods.

In this way, when the pressure of the internal space 116 in the arc tube portion 112 is maintained at a pressure, even among the visible light included in the light emitted by the self-discharge lamp 110, light with a relatively short wavelength (short-wavelength light), And the proportion of ultraviolet light also increases. When the proportion of short-wavelength light increases, the exposure efficiency of the photoresist provided on the exposure object X will increase upward. From the above reasons, the lighting method of the discharge lamp 110 according to this embodiment can contribute to the improvement of the exposure efficiency of the exposure object X.

(Modification 1) In the above embodiment, although the lighting method in the case of using the discharge lamp 110 as the lamp is briefly explained, however, an LED (light emitting diode) or a laser can also be used as the lamp instead. Discharge lamp 110.

Especially when LED is used as a lamp, the junction temperature of the LED (the temperature of the joint portion where the P-type semiconductor and the N-type semiconductor that generate heat when the LED emits light) is a ratio that reaches the point where the exposure In the case where power is continuously supplied to the LED, the exposure power is supplied in a shorter time until the LED reaches the constant contact temperature.

Therefore, the peak value of the irradiation intensity of the light (ultraviolet) from the LED generated after increasing the power supplied to the LED for each exposure time can be used (see Figure 13), so the exposure target can be more efficiently and effectively exposed. object is exposed.

Furthermore, in the above-mentioned embodiment, although the standby power L which is lower than the exposure power H is supplied outside the exposure time, when LED or laser is used as the lamp, it may also be used. It stops the power supply outside the exposure time to turn off the LED or laser.

(Modification 2) When LED or laser is used as the lamp, of course when the discharge lamp 110 is used, the irradiation intensity of the light irradiated by the light source device 100 during the self-exposure time may be set to a constant value, or it may be Instead, as shown in FIG. 14 , the continuous exposure time is divided into, for example, two ("first exposure time" and "second exposure time"), and the light emitted from the light source device 100 is changed during the first exposure time and the second exposure time. The intensity of light exposure.

In the above-mentioned FIG. 14 , an example is shown in which the irradiation intensity is increased during the first exposure time and is made weaker than the irradiation intensity during the second exposure time. However, it is of course also possible as shown in FIG. 15 . The irradiation intensity is weakened during the first exposure time and is made stronger than the irradiation intensity during the second exposure time. Alternatively, as shown in FIG. 16 , the irradiation intensity may be gradually increased during the first exposure time, and the irradiation intensity may be set to a constant value during the second exposure time. Furthermore, the continuous exposure time can be divided into three or more times; for example, as shown in Figure 17, the irradiation intensity can be gradually increased in the first exposure time; and a certain irradiation intensity can be maintained in the second exposure time; Gradually reduce the irradiation intensity during the third exposure time. Alternatively, as shown in FIG. 18 , the irradiation intensity may be rapidly increased during the first exposure time; the irradiation intensity may be suddenly dropped to the beginning and then become constant during the second exposure time; and the irradiation intensity may be rapidly increased during the third exposure time. After increasing to the initial level, it gradually decreases with a quadratic function. In this way, changing the irradiation intensity can be used when an LED laser is used as the lamp, and of course it can also be used when the discharge lamp 110 is used.

In this way, by changing the power supplied to the lamp during the exposure time, the power can be adjusted in a short time according to the degree of reaction of the photoresist, and the amount of light suitable for the photoreaction of the photoresist can be supplied.

The embodiments disclosed this time are, of course, non-restrictive because all points are merely examples. The scope of the present invention is not limited to the above description, but is intended to include what is disclosed in the patent application scope, and includes all changes within the meaning and scope that are equivalent to the patent application scope.

10…exposure machine 12…Integrator 14…concave mirror 16…irradiation surface 18…Incidence surface 20…Exit surface 21…flying eye lens 22…reflective concave surface 24…shutter 50…exposure device 52…frame 53…switch for discharge lamp 54…Power supply for discharge lamps 58…recess 60…Control Department 100…light source device 110…discharge lamp 112...Luminous tube department 114…Sealing part 116…internal space 118…foil 120…Electrode 122…lead rod 124…mercury 150…reflector 151…Reflector Container 152…reflective surface 154…Open your mouth 155…bottom of neck 156...Sealing part insertion hole 170…insulated abutment 172…Reflector insertion hole 174…inner space 176…Power cord insertion hole X...exposure object H…electricity for exposure L...standby power

FIG. 1 is a diagram showing an example of an exposure machine 10 applicable to the present invention. FIG. 2 is a diagram showing an example of the exposure device 50 applicable to the present invention. FIG. 3 is a plan view showing an example of the exposure device 50 applicable to the present invention. FIG. 4 is a cross-sectional view showing an example of the light source device 100 applicable to the present invention. FIG. 5 is a cross-sectional view showing an example of the discharge lamp 110. FIG. 6 is a graph showing an example of power supply to the discharge lamp 110 according to the lighting method of the present invention. FIG. 7 is a graph showing another example of power supply to the discharge lamp 110 according to the lighting method of the present invention. FIG. 8 is a graph showing another example of power supply to the discharge lamp 110 according to the lighting method of the present invention. FIG. 9 is a graph showing another example of power supply to the discharge lamp 110 according to the lighting method of the present invention. FIG. 10 is a graph showing another example of power supply to the discharge lamp 110 according to the lighting method of the present invention. FIG. 11 is a graph showing an example of the electric power supplied to the discharge lamp and the pressure in the internal space of the luminescent tube according to a conventional lighting method. FIG. 12 is a graph showing an example of the power supply to the discharge lamp 110 and the pressure in the internal space 116 of the arc tube part 112 according to the lighting method of the present invention. 13 is a graph showing an example of the relationship between the elapsed time from the start of supply of power to the LED and the irradiation intensity of light irradiated from the LED according to the lighting method according to Modification 1. FIG. 14 is a diagram showing an example of the irradiation intensity of light during the exposure time according to the lighting method according to Modification 2. FIG. 15 is a diagram showing an example of the irradiation intensity of light during the exposure time according to the lighting method according to Modification 2. FIG. 16 is a diagram showing an example of the irradiation intensity of light during the exposure time according to the lighting method according to Modification 2. FIG. 17 is a diagram showing an example of the irradiation intensity of light during the exposure time according to the lighting method according to Modification 2. FIG. 18 is a diagram showing an example of the irradiation intensity of light during the exposure time according to the lighting method according to Modification 2.

without.

Claims (2)

A method for lighting a lamp, which supplies exposure power to the lamp during the exposure time for exposing an exposure object; Outside the exposure time, supply standby power to the lamp, the standby power being lower than the exposure power and capable of maintaining the lighting state of the lamp; The aforementioned lamp is a discharge lamp; The supply time of the exposure power is shorter than the time required for the internal pressure of the discharge lamp to reach the constant internal pressure of the discharge lamp when the exposure power is continuously supplied to the discharge lamp. The method for lighting a lamp as described in claim 1, wherein during the exposure time, the irradiation intensity of the lamp is changed according to the light sensitivity of the exposed photoresist.