JP3150735B2 - Exposure equipment and mask film - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an exposure apparatus for forming a pattern on a work such as a copper-clad laminate or a ceramic substrate by photolithography, and a mask film used as an exposure microphone in the exposure apparatus.

[0002]

2. Description of the Related Art In a process of manufacturing a printed wiring board made of a copper-clad laminate, a work in which a resist layer is formed on the copper-clad laminate is used as a work, and light is irradiated through a mask to expose the resist. The resist is developed and patterned, and the copper layer of the copper-clad laminate is etched using the patterned resist as a mask to form a printed wiring board. In that case, a mask having a metal layer pattern formed on a glass plate is used as the mask. The pattern of the mask is such that a resist layer is formed on a glass surface with a metal layer formed, a pattern is formed on the resist by an electron beam, etc., developed, and a resist pattern is formed. It is what was etched as.

[0003]

Although a mask having a metal film pattern on a glass plate is convenient for forming a fine pattern, it is very expensive due to its manufacturing equipment and manufacturing method. In addition, there is a problem in safety because a glass plate is used. Each time a work is changed and a new mask is created, the number of glass masks themselves also increases, resulting in an increase in the number of storage locations for the mask and an increase in management costs. In addition, when changing workpieces,
The glass mask itself also has to be replaced, and the work and preparation of removing and attaching the mask from the reticle take time.

SUMMARY OF THE INVENTION An object of the present invention is to provide an exposure apparatus in which a mask for patterning a printed wiring board or a ceramic substrate can be easily formed or replaced. Another object of the present invention is to provide a mask film which is thus convenient for use in an exposure apparatus.

[0005]

The first aspect of the exposure apparatus of the present invention is as follows.
Is a mask film having a recording layer made of a thermoreversible material capable of recording an optical pattern by reversibly changing a transparent state and a cloudy state by heat and maintaining the two forms at room temperature. A thermal print head that records a mask pattern, a conveying unit that conveys a mask pattern recording unit of the mask film to a light irradiation position where the work is installed, and a light irradiation unit that exposes the work through the mask film at the light irradiation position, A control unit for controlling the operation of the thermal print head, the conveying unit, and the light irradiation unit;

[0006] The exposure equipment further comprises a heater for erasing by heating the pattern of the mask film, performs pattern recording to the mask pattern in the thermal print head, erase the pattern at the heater.

[0007] In another preferred embodiment of the exposure apparatus, the control means includes an interface for connecting the CAD / CAM apparatus or inputting image information created by the CAD / CAM apparatus, and performing thermal printing using the image information created by the CAD / CAM apparatus. A mask pattern can be drawn from the head. According to a second aspect of the exposure apparatus of the present invention, a recording layer capable of recording an optical pattern by heat is provided, and a plurality of mask patterns for a plurality of works are recorded and stored in the recording layer in advance. A thermal print head that records a mask pattern on a mask film that can be formed, a conveying unit that conveys a mask pattern recording unit of the mask film to a light irradiation position where the work is installed, and a light that exposes the work through the mask film at the light irradiation position. Irradiating means, and a selection circuit for selecting a corresponding mask pattern along with the change of the work and transporting the selected mask pattern to a light irradiation position;
A control unit for controlling the operation of the thermal print head, the conveying unit, the light irradiation unit, and the selection circuit is provided.

The mask film of the present invention has rollers at both ends with a window frame interposed therebetween, and between the rollers, a transparent state and a cloudy state are reversibly changed by heat so that an optical pattern can be recorded. A recording section having a thermal print head, wherein a mask film having a recording layer made of a thermoreversible material capable of maintaining the two forms at room temperature is wound so that the mask film can move through a window frame portion; It is in the form of a cartridge which is detachably mounted and used in an exposure apparatus provided with a light irradiating means for irradiating the work with light and a transport means for driving a roll to move the mask film.

[0009]

In order to prepare a mask for exposing a specific work, a mask pattern is recorded on a mask film having a recording layer made of a thermoreversible material by a thermal print head, and the recorded portion is exposed to light. The workpiece is conveyed to the irradiation position, and the work is irradiated with light from the light irradiation means using the recorded mask pattern as a mask, and the work is exposed. The mask film has a recording layer made of a thermoreversible material capable of recording an optical pattern by reversibly changing a transparent state and a cloudy state by heat and maintaining the two forms at room temperature. Therefore, when the type of work is changed, the mask film used once can be erased on the mask film and a new mask pattern can be recorded again.

[0010] Then, because the erasure mask pattern of the recording layer formed by thermally reversible material in a dedicated heater,
The pattern recording by the thermal head and the pattern erasing by the heater can be simultaneously performed at different positions. If the mask pattern to be recorded by the thermal print head is created by a CAD / CAM device, the pattern can be easily created. If a plurality of mask patterns are recorded in advance on a mask film and a predetermined mask pattern is selected according to a change of a work, the mask pattern can be exchanged quickly. The cartridge-shaped mask film can be easily replaced when the mask film is deteriorated or damaged.

[0011]

FIG. 1 shows an exposure apparatus on which the present invention is based .
The mask film 2 having a recording layer on which an optical pattern can be recorded by heat is formed by a pair of capstan rollers 4a and 4b.
And is pressed between the capstan rollers 4a and 4b by the thermal print head 6 and the platen roller 8. Capstan rollers 4a, 4b
The rotation of the platen roller 8 causes the mask film 2 to be conveyed in any of the reciprocating directions (A, B). When the mask film 2 is transported in the direction A, the heating element is heated by the thermal print head 6 in accordance with the image information, and a mask pattern is written on the mask film 2.

At another position between the capstan rollers 4a and 4b, a work 10 having a photoresist layer formed on a copper-clad laminate, a ceramic substrate, or the like is installed on one side at another position. On the opposite side of the mask film 2, a lamp house 12 is provided as light irradiation means. Reference numeral 14 denotes an ultraviolet light source in the lamp house 12. At the light irradiation position, the mask pattern is set within the ultraviolet irradiation range, and the work 10 is also set within the ultraviolet irradiation range. Reference numeral 16 denotes control means. The control means 16 includes a motor drive circuit 18 for driving the capstan rollers 4a and 4b,
A platen motor drive circuit 22 for driving the platen roller 8, a thermal print head (THP) drive circuit 20 for driving the operation of the thermal head 6, a light source drive circuit 24 for driving the light source 14, and their drive circuits 18, 20,
A CPU 26 for controlling the ROMs 22 and 24;
M30 and the like are provided.

FIG. 2 shows an example of the mask film 2. This mask film has a recording layer 34 formed on a transparent polyester film 32 and an overcoat layer 36 formed on the recording layer 34 to protect the recording layer.
Proceedings of the Non-Impact Printing Technology Symposium, pp. 57-60 (sponsored by the Electrographic Society of Japan in 1987)). The recording layer 34 includes an organic low molecular substance 34 in a resin 34a.
b is in a dispersed state. The recording layer 34 is formed by applying a solution in which a resin and an organic low-molecular substance are dissolved in a solvent on a transparent film 34, heating and drying. Organic low molecular weight substance 34b during drying by heating
Is precipitated and dispersed in the resin 34a. This mask film has thermoreversibility and can be in a transparent state or a cloudy state. The difference between the transparent state and the cloudy state depends on the size of the crystals in the particles of the organic low-molecular substance 34b dispersed in the resin 34a.

FIG. 3 shows the thermoreversible characteristics of this mask film. Now, suppose that it is in a cloudy state at room temperature. When this is heated, the transmittance starts to increase from the temperature T ₁ and reaches a maximum transparent state at the temperature T ₂ . Then, when it is cooled to room temperature, the transparent state is maintained (solid line). This low-molecular organic material 34b in the process of raising the temperature from temperatures T ₁ to T ₂ is a polycrystalline opaque state and a semi-molten state, again crystals grown into a single crystal of a transparent state when it is cooled to room temperature It is believed to be. Next, when reheating the mask film of the transparent state to a temperature T ₃ or more, the intermediate state of the maximum transparent state and the maximum opaque state. When it is cooled to room temperature, it returns to the original cloudy state (broken line). This melted organic low-molecular material 34b at a temperature T ₃ or more, are considered to polycrystalline in the process of cool to room temperature is used to deposit. It is also disclosed in the above document that the characteristics are not changed even when the pattern formation and erasure on the mask film by heat are repeated 500 times.

Next, the operation of the exposure apparatus shown in FIG. 1 will be described. The mask film 2 is pressed by the thermal print head 6 and the platen roller 8, and the capstan roller 4a,
It is transported in the direction A by 4b. At this time, each heating element of the thermal print head 6 generates heat in accordance with the image information, and a mask pattern is written on the mask film 2. After the patterning is completed, the mask setting is completed by setting the patterned portion under the lamp house 12 of the light irradiation means, that is, at the ultraviolet irradiation position. After the mask setting is completed, the work 10 is set in the ultraviolet irradiation range similarly to the mask pattern. At this time, the light source 14 is set via the mask film 2. A resist of a photosensitive agent is applied to the surface of the work 10 on the mask side. Therefore,
After the completion of the work setting, the pattern of the mask film is exposed on the work 10 by irradiating ultraviolet light from the light source 14.

If the dot density of the thermal print head 6 is assumed to be 16 dpm, a pattern can be formed at a minimum pitch of 62 μm. Such a density is a sufficient dot density when a copper-clad laminate or a ceramic substrate is used as a work. Next, when the work is changed, the mask pattern also needs to be changed. In this case, all the heating elements of the thermal print head 6 generate heat while transporting the mask film 2 in the B direction. Thereby,
The entire surface of the mask film 2 becomes transparent, and the mask pattern can be written again. Then,
While transferring the mask film 2 in the direction A, a new mask pattern is recorded by the thermal print head 6 for a new work.

FIG. 4 shows a first embodiment. Figure 1 Exposure
Compared with the apparatus , the apparatus further includes a heater 40 for heating and erasing the pattern of the microphone film, and recording the pattern on the mask film 2 by the thermal print head 6.
In that the pattern of the mask film 2 is erased by the heater 40. In order to drive the heater 40, the controller 16a includes a heater driving circuit 4
2 is further provided, and the operation of the heater drive circuit 42 is also controlled by the CPU 26.

FIG. 5 shows a second embodiment. Figure 1 Exposure
Compared with the device , the control means 16b includes an interface 44 for connecting the CAD / CAM device 46 or inputting image information created by the CAD / CAM device 46,
A difference is that a mask pattern can be drawn on the mask film 2 from the thermal print head 6 by image information created by the CAM device 46. Also in FIG. 5, the erasing heater 4 is used to erase the recorded pattern.
0 is provided.

FIG. 6 shows a third embodiment. Figure 1 Exposure
Compared to the apparatus , the mask film 2 can record and store a plurality of mask patterns for a plurality of works in advance, and the control means 16c changes the corresponding mask pattern with the change of the work. Mask pattern selection circuit 4 for selecting and transporting to the light irradiation position
8 is different. FIG. 6 shows a mask sheet 2 on which a plurality of types of mask patterns are recorded in advance.
Is wound around the capstan roller 4a or 4b. The mask pattern of the required work is set in the ultraviolet irradiation range, and the other patterns are the capstan roller 4a.
Alternatively, when the workpiece is changed, the corresponding mask pattern is conveyed to the ultraviolet irradiation position and set.

FIG. 7 shows a mask film cartridge suitable for use in the exposure apparatus of the present invention. This cartridge has a roller 62a corresponding to the capstan roller 4a at one end and a roller 62b corresponding to the capstan roller 4b at one end with the window frame 60 interposed therebetween, and a mask film 2 between the rollers 62a and 62b. Is wound, and the mask film 2 is movably held in the window frame portion. When the mask film 2 is deteriorated or damaged, the mask film 2 is replaced for each cartridge. The present invention is not limited to the exposure apparatus having the configuration shown in the embodiment, but can be appropriately modified so as to achieve the object.

[0021]

According to the present invention, in order to form a mask for exposing a specific work, a mask pattern is recorded on a mask film having a recording layer made of a thermoreversible material by a thermal print head. The recorded portion is conveyed to a light irradiation position, and the work is performed by irradiating the work with light from the light irradiation means using the recorded mask pattern as a mask, so that the mask is compared to using a conventional glass mask. Material costs are reduced and safety is improved. Further, since the recording layer of the mask film is made of a thermoreversible material, when the type of work is changed, the mask film used once can be erased and a new mask pattern can be recorded again. In this case, since the number of masks to be stored does not increase, mask management costs are reduced. Also, conventionally, the glass mask itself was replaced with the change of the mask pattern, but in the present invention, the mask pattern can be changed with the same mask film, so that there is no need for time-consuming mask replacement or adjustment work, Significant reduction in man-hours can be achieved during high-mix low-volume production.

Further, since the erasing of the mask pattern of the recording layer formed by thermally reversible material in a dedicated heater, it is carried out simultaneously at different locations and a pattern erasing pattern recording and heater of a thermal head Work efficiency can be improved. If a mask pattern to be recorded by a thermal print head is created by a CAD / CAM apparatus, it is easy to change or correct the mask pattern when the mask pattern is changed. Search is also possible. As a result, it is possible to significantly reduce the cost and period during design and development. If a plurality of mask patterns are recorded in advance on a mask film and a predetermined mask pattern is selected according to a change of a work, the mask pattern can be exchanged quickly. The transparent state and the cloudy state can be reversibly changed to record an optical pattern,
Use of a cartridge-shaped mask film having a recording layer made of a thermoreversible material that can maintain the two forms at room temperature enables re-recording of the mask pattern and replacement when the mask film is deteriorated or damaged. Easier to do.

[Brief description of the drawings]

FIG. 1 is a schematic configuration diagram showing an exposure apparatus on which the present invention is based .

FIG. 2 is a schematic sectional view showing a mask film used in one embodiment.

FIG. 3 is a diagram showing thermoreversible characteristics of the mask film of FIG.

FIG. 4 is a schematic configuration diagram showing a first embodiment.

FIG. 5 is a schematic configuration diagram showing a second embodiment.

FIG. 6 is a schematic configuration diagram showing a third embodiment.

FIG. 7 is a perspective view showing an example of a cartridge-shaped mask film.

[Explanation of symbols]

 2 Mask film 4a, 4b Capstan roller 6 Thermal print head 8 Platen roller 10 Work 12 Lamp house 14 Light source 16, 16a, 16b, 16c Controller 44 Interface 46 CAD / CAM device 60 Window frame 62a, 62b Roller

Claims (4)

(57) [Claims] 1. A mask film having a recording layer made of a thermoreversible material capable of recording an optical pattern by reversibly changing between a transparent state and a cloudy state by heat and maintaining the two forms at room temperature. A thermal print head for recording a mask pattern on the mask, a conveying means for conveying a mask pattern recording portion of the mask film to a light irradiation position where the work is installed, and a light irradiation means for exposing the work through the mask film at the light irradiation position. To heat and erase the mask film pattern
Heating heater, the thermal print head, transport means , light irradiating means and
It controls the operation of the fine the heater, the mask film
Pattern recording with the thermal print head
And a control means for causing the heater to erase the pattern . 2. The control means includes an interface for connecting a CAD / CAM device or inputting image information created by the CAD / CAM device, and from the thermal print head to the mask film based on the image information created by the CAD / CAM device. 2. The exposure apparatus according to claim 1 , wherein a mask pattern can be drawn. 3. A mask film having a recording layer capable of recording an optical pattern by heat, wherein a plurality of mask patterns for a plurality of works are previously recorded and stored in the recording layer. Thermal print head for recording, transport means for transporting the mask pattern recording portion of the mask film to the light irradiation position where the work is installed, light irradiation means for exposing the work through the mask film at the light irradiation position, change of the work An exposure apparatus comprising: a selection circuit that selects a corresponding mask pattern and transports the selected mask pattern to a light irradiation position, and a control unit that controls operations of the thermal print head, the transport unit, the light irradiation unit, and the selection circuit. 4. A roller is provided at both ends with a window frame interposed therebetween, and between the two rollers, a transparent state and a cloudy state are reversibly changed by heat to record an optical pattern. A mask film having a recording layer made of a thermoreversible material capable of maintaining its form is wound so that the mask film can move through a window frame portion, and irradiates a recording portion with a thermal print head and a work with light. A cartridge-shaped mask film which is detachably mounted and used in an exposure apparatus provided with a light irradiation means and a transport means for driving the roll to move the mask film.