CN111466011A

CN111466011A - Method for lighting lamp

Info

Publication number: CN111466011A
Application number: CN201880076452.4A
Authority: CN
Inventors: 池田富彦
Original assignee: Phoenix Electric Co Ltd
Current assignee: Phoenix Electric Co Ltd
Priority date: 2017-12-08
Filing date: 2018-11-27
Publication date: 2020-07-28
Anticipated expiration: 2038-11-27
Also published as: CN111466011B; JP7278596B2; TW202324501A; KR20200096916A; TW201931438A; WO2019111769A1; TWI815773B; TWI794352B; JPWO2019111769A1

Abstract

The invention provides a method for lighting a lamp, which can reduce the wasted power which does not contribute to the exposure of an exposure object and can realize the long service life of the lamp. The lamp is supplied with exposure power during an exposure period in which an exposure object (X) is exposed, and standby power which is lower than the exposure power and can maintain the lamp in a lighting state is supplied to the lamp during a period other than the exposure period.

Description

Method for lighting lamp

Technical Field

The present invention relates to a method of lighting a lamp that emits light for exposure of a printed wiring board or the like, for example.

Background

Conventionally, in order to mount a component on an electronic device, a printed wiring board in which a wiring pattern is formed on a substrate made of resin or glass epoxy material with a metal such as copper has been used. The wiring pattern on these printed wiring boards is formed by photolithography. Photolithography is performed by applying a photoresist, which is a photosensitive chemical, to the entire surface of a substrate on which a metal layer is formed as a wiring, and irradiating the photoresist with light from an exposure device through the same photomask as the wiring pattern.

Among the photoresists, there are negative type photoresists in which the solubility of the photoresist is reduced by irradiation light, and conversely, positive type photoresists in which the solubility of the photoresist is increased by irradiation light. When the photoresist portion having a relatively increased solubility by irradiation with light is removed by chemical treatment and the exposed metal layer is removed by etching, only the metal layer located under the portion where the photoresist remains, and the photoresist is removed, thereby forming a wiring pattern on the substrate. When irradiation light is irradiated to either a positive-type or negative-type photoresist, a discharge lamp having a large amount of light emission per lamp on average is used as a light source in order to ensure a uniform exposure amount over the entire surface of the irradiated surface.

In the discharge lamp, arc discharge is generated between a pair of electrodes disposed apart from each other in an airtight internal space of the arc tube, and mercury enclosed in the internal space is excited to emit ultraviolet light.

Depending on the kind of the photoresist, the most suitable exposure time, that is, the length of time for which the photoresist is irradiated with light from the discharge lamp is determined. Therefore, it is generally practiced to arrange a shutter (shutter) between the discharge lamp and the exposure object (such as a photoresist), open the shutter for a required time to expose the exposure object for an optimal exposure time, and close the shutter for the other time (for example, a time for replacing the exposure object) (for example, patent document 1).

Documents of the prior art

Patent document

Patent document 1: JP 2002-373840 publication

Disclosure of Invention

(problems to be solved by the invention)

However, the conventional exposure method has a problem. Since the exposure time is controlled by the shutter and the lamp needs to be continuously lighted even when exposure is not performed, not only is power wasted, but also the life of the lamp that always emits light at the rated power cannot be prolonged.

The present invention has been made in view of the above problems, and an object of the present invention is to provide a method for lighting a discharge lamp, which can reduce wasteful power that does not contribute to exposure of an exposure object, and can extend the life of the lamp.

(means for solving the problems)

According to an aspect of the present invention, there is provided a lamp lighting method including the steps of: supplying exposure power to the lamp during an exposure period in which an exposure object is exposed; and supplying standby power, which is lower than the exposure power and can maintain the lighting state of the lamp, to the lamp in a period except the exposure period.

Preferably, the lamp is a discharge lamp, and the time during which the exposure power is supplied is shorter than a time during which the internal pressure of the discharge lamp reaches a steady-state internal pressure of the discharge lamp when the exposure power is continuously supplied to the discharge lamp.

Preferably, the lamp is L ED (light emitting diode), and the time for supplying the exposure electric power is shorter than the time for the junction temperature of the L ED to reach the steady-state junction temperature of the L ED in a case where the exposure electric power is continuously supplied to the L ED.

Preferably, when the lamp is L ED, the power supply to the lamp is stopped and the lamp is turned off during a period other than the exposure period.

Preferably, the irradiation intensity from the lamp is varied between the exposure periods in correspondence with the light receiving sensitivity of the photoresist subjected to the exposure.

(effect of the invention)

According to the present invention, it is possible to provide a lamp lighting method capable of reducing wasteful power that does not contribute to exposure of an exposure object and prolonging the life of a lamp.

Drawings

Fig. 1 is a diagram showing an example of an exposure apparatus 10 to which the present invention is applied.

Fig. 2 is a diagram showing an example of an exposure apparatus 50 to which the present invention is applied.

Fig. 3 is a plan view showing an example of an exposure apparatus 50 to which the present invention is applied.

Fig. 4 is a cross-sectional view showing an example of a light source device 100 to which the present invention is applied.

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 supplied to the discharge lamp 110 by the lighting method according to the present invention.

Fig. 7 is a graph showing another example of the electric power supplied to the discharge lamp 110 by the lighting method according to the present invention.

Fig. 8 is a graph showing another example of the electric power supplied to the discharge lamp 110 by the lighting method according to the present invention.

Fig. 9 is a graph showing another example of the power supplied to the discharge lamp 110 by the lighting method according to the present invention.

Fig. 10 is a graph showing another example of the electric power supplied to the discharge lamp 110 by the lighting method according to the present invention.

Fig. 11 is a graph showing an example of power supplied to the discharge lamp and the pressure in the internal space of the light-emitting tube portion by the conventional lighting method.

Fig. 12 is a graph showing an example of the power supplied to the discharge lamp 110 and the pressure in the internal space 116 of the light-emitting tube section 112 by the lighting method according to the present invention.

Fig. 13 is a graph showing an example of a relationship between elapsed time from the start of supply of power to L ED and irradiation intensity of light irradiated from L ED, based on the lighting method according to modification 1.

Fig. 14 is a diagram showing an example of the irradiation intensity of light during an exposure period based on the lighting method according to modification 2.

Fig. 15 is a diagram showing an example of the irradiation intensity of light during an exposure period by the lighting method according to modification 2.

Fig. 16 is a diagram showing an example of the irradiation intensity of light during an exposure period based on the lighting method according to modification 2.

Fig. 17 is a diagram showing an example of the irradiation intensity of light during an exposure period by the lighting method according to modification 2.

Fig. 18 is a diagram showing an example of the irradiation intensity of light during an exposure period by the lighting method according to modification 2.

Detailed Description

(example 1)

(constitution of Exposure machine 10)

Fig. 1 shows an exposure machine 10 according to embodiment 1 to which the present invention is applied. 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 having a wavelength suitable for exposure of the exposure object X. The exposure device 50 will be described in detail after the configuration of the exposure machine 10 is described.

The integrator 12 has: an incident surface 18 that receives light from the exposure device 50; and an exit surface 20 that emits the received light on the basis of improving uniformity of the light. A plurality of fly-eye lenses 21 are formed on the incident surface 18 and the emission surface 20, respectively.

Concave mirror 14 has a reflective concave surface 22 on its inner side. The concave mirror 14 reflects the light emitted from the integrator 12 by the concave reflection surface 22 to be parallel light.

The irradiation surface 16 is a surface that receives the parallel light from the concave mirror 14, and is disposed in a direction substantially perpendicular to the parallel light. An exposure object X is placed on the irradiation surface 16. A photosensitive agent or a photoresist is applied to the surface of the exposure object X, for example. The parallel light from the concave mirror 14 irradiates a desired region in the exposure object X, thereby forming a desired circuit pattern or the like on the surface of the exposure object X.

The shutter 24 is a device that opens and closes a passage (optical path) of light from the discharge lamp 110, and is disposed on the emission surface 20 side of the integrator 12. By opening the shutter 24 in accordance with the exposure period of the exposure object X, the light from the discharge lamp 110 reaches the exposure object X, and by closing the shutter 24 in a period other than the exposure period, the light from the discharge lamp 110 does not undesirably reach the irradiation surface 16. The position at which the shutter 24 is disposed is not limited to this embodiment, and may be disposed at another position on the optical path from the discharge lamp 110 to the exposure object X.

(constitution of Exposure apparatus 50)

Fig. 2 is a diagram showing an exposure apparatus 50 according to example 1 to which the present invention is applied. 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. As shown in fig. 4, the light source device 100 is substantially composed of a discharge lamp 110, a reflector 150, and an insulating substrate 170. The reflector 150 and the insulating base 170 may be collectively referred to as a reflector container 151.

As shown in fig. 5, the discharge lamp 110 includes a light-emitting tube part 112 and a pair of sealing parts 114 extending from the light-emitting tube part 112. The light emitting tube part 112 and the pair of sealing parts 114 are integrally formed of quartz glass. Further, an internal space 116 sealed by the sealing portion 114 is formed in the light emitting tube portion 112.

In each sealing portion 114 of the discharge lamp 110, there are provided: an embedded molybdenum foil 118; a pair of electrodes 120 made of tungsten, one end of which is connected to one end of the foil 118 and the other end of which is disposed in the internal space 116; and a pair of guide rods 122 having one end connected to the other end of the foil 118 and the other end extending outward from the sealing part 114. Further, a predetermined amount of mercury 124 and halogen (e.g., bromine) are sealed in the internal space 116.

When a predetermined high voltage is applied to a pair of guide rods 122 provided in the discharge lamp 110, a glow discharge that starts between a pair of electrodes 120 provided in the internal space 116 of the bulb 112 is converted into an arc discharge, and light (mainly ultraviolet rays) is emitted by the mercury 124 evaporated and excited by the arc.

Referring back to fig. 4, in the light source device 100 according to the present embodiment, one seal portion 114 is inserted into the seal portion insertion hole 156 of the reflector 150. The discharge lamp 110 may be used for ac lighting or dc lighting.

The reflector 150 has a bowl-shaped reflecting surface 152 on its inner side surface. The reflecting surface 152 reflects a part of the light from the discharge lamp 110, and the discharge lamp 110 is arranged such that the light-emitting tube part 112 is positioned inside the reflector 150. In the present embodiment, the reflecting surface 152 is defined by a paraboloid of revolution. The light emitting point of the discharge lamp 110 (approximately the center of the arc formed between the pair of electrodes 120 in the internal space 116) coincides with the focal point of the paraboloid of revolution. Accordingly, light emitted from the light emitting point of the discharge lamp 110 and reflected by the reflecting surface 152 is substantially parallel to light emitted from the opening 154 of the reflector 150. Of course, the shape of the reflecting surface 152 is not limited to this, and may be a surface of revolution, another surface of revolution, or a shape other than a surface of revolution. Further, the light-emitting point does not necessarily have to be aligned with the focal point, and the light-emitting point may be shifted from the focal point as necessary.

In addition, a bottomed neck portion 155 is provided to protrude from the reflector 150 on the side opposite to the opening 154. Further, a sealing portion insertion hole 156 into which one sealing portion 114 of the discharge lamp 110 is inserted is formed in the reflection surface 152 of the reflector 150. The seal portion insertion hole 156 is formed from the bottom of the reflection surface 152 to 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 from the discharge lamp 110 advances forward of the reflector 150 in a range having a predetermined angle (opening angle) around the light advancing along the center axis C L of the reflecting surface 152.

Returning to fig. 4, the insulating base 170 is formed of an electrical insulator such as ceramic, and is formed with a reflector insertion hole 172 into which the bottom neck portion 155 of the reflector 150 and one sealing portion 114 of the discharge lamp 110 inserted into the sealing portion insertion hole 156 are inserted. By inserting the bottom neck portion 155 and the sealing portion 114 into the reflector insertion hole 172, the insulating substrate 170 covers the sealing portion insertion hole 156 from the outside.

Further, an inner space 174 communicating with the reflector insertion hole 172 is formed in the insulating base 170, and a power cable insertion hole 176 for allowing the inner space 174 and the outside to communicate with each other and allowing the power cable a to be inserted therethrough is formed.

Further, 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. Specifically, the end of the bottom neck portion 155 of the reflector 150 and one of the sealing portions 114 of the discharge lamp 110 are inserted into the reflector insertion hole 172 of the insulating base 170, and the inorganic adhesive C is filled in the inner space 174 of the insulating base 170 in a state where the power supply cable a is disposed in the inner space 174.

Returning to fig. 3, the frame 52 is a substantially rectangular parallelepiped member formed with a plurality of recesses 58 for mounting a plurality of light source devices 100

Returning to fig. 2, the discharge lamp power supply 54 supplies necessary electric power to the discharge lamp 110 of each light source device 100 attached to the frame 52. The discharge lamp switch 53 turns on or off the current supplied to the discharge lamp 110.

Specifically, as shown in fig. 6, when the discharge lamp power source 54 exposes the exposure object X, the control unit 60 supplies exposure power H (for example, rated power of the discharge lamp 110) for a time (exposure time) required for the exposure, and controls the discharge lamp 110 to supply standby power L that is lower than the exposure power H and can maintain the lighting state of the discharge lamp 110, during a period other than the exposure period.

Although fig. 6 shows an example in which the discharge lamp power source 54 supplies the pulse wave-shaped exposure power H, the waveform of the exposure power H supplied to the discharge lamp power source 54 is not limited to this, and may be increased and decreased in a linear function (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 (parabolic type) as shown in fig. 7, for example, the value of the exposure power H in the exposure period may not be constant as shown in fig. 8, and even in the case where a high amount of exposure power is supplied in the first half of the exposure period and a low amount of exposure power is supplied in the second half of the exposure period as shown in fig. 8, the amount of power supplied (value obtained by integrating power with time) in the exposure period may be equal to the patterns of fig. 6 and 7, and the discharge lamp may be changed in accordance with the characteristics of the exposure object X (for example) to change the light emission intensity of the discharge lamp 110 as shown in fig. 9 and 10.

By changing the power supplied to the discharge lamp 110 during the exposure period in this manner, the power can be adjusted for a short time in accordance with the degree of reaction of the photoresist, and the amount of light suitable for the photoreaction of the photoresist can be supplied.

(operation of Exposure device 50)

When a power switch (not shown) of the exposure apparatus 50 is turned on, the discharge lamp switch 53 is turned on to start supplying power from the discharge lamp power supply 54 to the discharge lamp 110 of the light source apparatus 100, and when the power supply is started, the discharge lamp 110 is turned on, and at this stage, the power supplied from the discharge lamp power supply 54 to the discharge lamp 110 is the standby power L.

Then, when the exposure work for the exposure object X is started and the exposure object X is placed on the irradiation surface 16 of the exposure machine 10, the discharge lamp power supply 54 supplies the discharge lamp 110 with exposure power H higher than the initial power for a predetermined time (that is, a predetermined exposure time). At the same time, the shutter 24 of the exposure machine 10 is opened, and the exposure object X is irradiated with the exposure light from the discharge lamp 110, thereby performing the exposure operation.

When the predetermined exposure time is reached, the shutter 24 is closed, and the power supplied from the discharge lamp power supply 54 to the discharge lamp 110 is returned from the exposure power H to the standby power L.

(features of Exposure apparatus 50)

According to the present embodiment, when the shutter 24 is closed and the exposure of the exposure object X is not performed, the discharge lamp 110 is supplied with the standby power L from the discharge lamp power supply 54, and when the shutter 24 is opened and the exposure of the exposure object X is to be performed, the discharge lamp 110 is supplied with the exposure power H higher than the standby power L from the discharge lamp power supply 54.

Accordingly, when the shutter 24 is closed and the exposure of the exposure object X by the light from the discharge lamp 110 does not contribute, the low standby power L is supplied to the discharge lamp 110, and thus the wasteful power can be reduced.

In addition, compared to the conventional method in which the discharge lamp 110 is continuously lit at the rated power all the time, the available time in the case where the discharge lamp 110 is lit at the standby power L lower than the rated power is longer, and therefore, the life of the discharge lamp 110 can be extended.

Furthermore, focusing on the pressure in the internal space 116 of the light-emitting tube section 112 in the discharge lamp 110 being lit, in the case of the conventional method of continuously lighting the discharge lamp 110 at the rated power at all times, as shown in fig. 11, the power supplied to the discharge lamp 110 and the pressure in the internal space 116 are substantially constant, whereas in the case of the lighting method of the discharge lamp 110 according to the present embodiment, as shown in fig. 12, the pressure in the internal space 116 when the standby power L is supplied is low, and when the supply of the exposure power H is started, the pressure starts to rise, becomes maximum when the exposure power H returns to the standby power L, and starts to fall.

According to the lighting method of the discharge lamp 110 of the present embodiment, the time for supplying the exposure electric power H is shorter than the time for the internal pressure of the discharge lamp 110 (the pressure of the internal space 116 in the light-emitting tube section 112) to reach the steady-state internal pressure of the discharge lamp 110 (that is, the pressure state illustrated in fig. 8) in the case where the exposure electric power H is continuously supplied to the discharge lamp 110. Therefore, even if the exposure power H used when the exposure operation of the exposure object X is performed is made to be equal to the rated power in the conventional method and the same amount of light is emitted, the peak pressure of the internal space 116 in the light-emitting tube portion 112 of the discharge lamp 110 can be suppressed to be lower than that in the case of the conventional method.

When the pressure in the internal space 116 in the light-emitting tube portion 112 is kept low in this way, the ratio of light (short-wavelength light) having a shorter wavelength among visible light and ultraviolet light included in the light emitted from the discharge lamp 110 increases. If the ratio of the short wavelength light is increased, the exposure efficiency of the resist provided on the exposure object X is improved. As described above, the lighting method of the discharge lamp 110 according to the present embodiment can contribute to improvement of the exposure efficiency of the exposure object X.

(modification 1)

Although the lighting method in the case of using the discharge lamp 110 as the lamp has been described in the above embodiment, L ED (light emitting diode) or a laser may be used as the lamp instead of the discharge lamp 110.

In particular, when L ED is used as a lamp, exposure electric power is supplied in a shorter time than the time until the junction temperature of L ED (the temperature of a junction portion where a P-type semiconductor and an N-type semiconductor are joined together, which generates heat when L ED emits light) reaches the steady-state junction temperature of L ED when exposure electric power is continuously supplied to L ED.

Accordingly, the peak of the irradiation intensity of light (ultraviolet light) from L ED generated immediately after the power supplied to L ED is increased can be used in each exposure period (see fig. 13), and therefore, the exposure target can be more efficiently exposed.

Further, although the standby power L lower than the exposure power H is supplied in the above embodiment in the period other than the exposure period, in the case of using L ED or a laser as the lamp, the supplied power may be stopped in the period other than the exposure period to turn off the L ED or the laser.

(modification 2)

When L ED or a laser is used as the lamp, it is needless to say that the irradiation intensity of the light irradiated from the light source device 100 may be constant in the exposure period in any case when the discharge lamp 110 is used, but instead of this, as shown in fig. 14, the continuous exposure period may be divided into, for example, 2 periods ("first exposure period" and "second exposure period"), and the irradiation intensity of the light irradiated from the light source device 100 may be changed between the first exposure period and the second exposure period.

Although fig. 14 shows an example in which the irradiation intensity is increased during the first exposure period and decreased during the second exposure period, it is needless to say that the irradiation intensity may be decreased during the first exposure period and increased during the second exposure period as shown in fig. 15, the irradiation intensity may be increased during the first exposure period and may be kept constant during the second exposure period as shown in fig. 16, for example, the continuous exposure period may be divided into 3 or more continuous exposure periods, and the irradiation intensity may be increased during the first exposure period, the irradiation intensity may be kept constant during the second exposure period, and the irradiation intensity may be decreased during the third exposure period as shown in fig. 18, the irradiation intensity may be increased sharply during the first exposure period, the irradiation intensity may be kept constant after the first sharp drop during the second exposure period, and the irradiation intensity may be decreased as a secondary function after the first sharp increase during the third exposure period as shown in fig. 18, and the irradiation intensity may be decreased in both cases where L and 110 are used as a laser.

By changing the power supplied to the lamp during the exposure period in this manner, the power can be adjusted for a short time in accordance with the degree of reaction of the photoresist, and the amount of light suitable for the photoreaction of the photoresist can be supplied.

It should be understood that the embodiments disclosed herein are illustrative and not restrictive in all respects. The scope of the present invention is defined not by the above description but by the claims, and is intended to include all modifications within the scope and meaning equivalent to the claims.

(description of reference numerals)

10 … exposure machine, 12 … integrator, 14 … concave mirror, 16 … irradiation surface, 18 … incidence surface, 20 … emergence surface, 21 … fly eye lens, 22 … reflection concave surface, 24 … shutter

50 … exposure device, 52 … frame, 53 … switch for discharge lamp, 54 … power supply for discharge lamp, 58 … recess, 60 … control part

100 … light source device

110 … discharge lamp, 112 … luminous tube part, 114 … sealing part, 116 … internal space, 118 … foil, 120 … electrode, 122 … guide rod, 124 … mercury

150 … reflector, 151 … reflector container, 152 … reflecting surface, 154 … opening, 155 … bottom neck, 156 … sealing part insertion hole

170 … insulating base, 172 … reflector insertion hole, 174 … inner space, 176 … power cable insertion hole

X … exposure object, H … exposure electric power, L … standby electric power.

Claims

1. A method of lighting a lamp, comprising the steps of:

supplying exposure power to the lamp during an exposure period in which an exposure object is exposed; and

in a period other than the exposure period, standby power that is lower than the exposure power and can maintain a lighting state of the lamp is supplied to the lamp.

2. The lighting method according to claim 1,

the lamp is a discharge lamp, and the time for supplying the exposure power is shorter than the time for the internal pressure of the discharge lamp to reach the steady-state internal pressure of the discharge lamp when the exposure power is continuously supplied to the discharge lamp.

3. The lighting method according to claim 1,

the lamp is L ED, and the time for supplying the exposure electrical power is shorter than the time for the junction temperature of the L ED to reach the steady-state junction temperature of the L ED with the continuous supply of the exposure electrical power to the L ED.

4. The lighting method according to claim 3,

in a period other than the exposure period, the power supply to the lamp is stopped to turn off the lamp.

5. The lighting method according to any one of claims 1 to 4,

the irradiation intensity from the lamp is varied between the exposure periods in accordance with the light receiving sensitivity of the photoresist to be exposed.