JP4479322B2 - Three-dimensional exposure mask and three-dimensional exposure method - Google Patents

Description

  The present invention relates to a three-dimensional exposure mask used when pattern exposure is performed on a three-dimensional free-form surface of a material to be exposed such as a printed wiring board.

In recent years, due to demands for miniaturization and space saving of electronic devices, high-density mounting of electronic components and the like has become necessary. However, planar printed wiring boards often cannot meet the demand. It is becoming visible.
In view of this, the circuit pattern forming surface of the substrate is formed in a three-dimensional shape to reduce the space occupied by the substrate. And as shown to patent document 1, the technique which performs the exposure for patterning on the pattern formation surface of a board | substrate of such a three-dimensional shape is proposed.

  The exposure apparatus disclosed in Patent Document 1 collects a beam generated from a beam generating unit by a variable focal length lens or the like to form a beam spot, and a target to be exposed set on a turntable is relative to the beam spot. Thus, it is possible to expose a member to be exposed formed in a three-dimensional shape.

JP 2003-220478 A

However, since the exposure apparatus disclosed in Patent Document 1 performs exposure by scanning a beam spot on the member to be exposed, a lot of time is required to expose the entire surface of the member to be exposed. It was. In particular, the exposure time increases as the spot diameter is reduced for miniaturization and as the substrate size of the exposed member is increased.
In addition, the exposure equipment's mechanism is complicated, such as using a variable focal length lens for the condensing function and a three-dimensional rotation mechanism for correcting the optical axis. It was.
Therefore, the present invention provides a three-dimensional exposure mask and a three-dimensional exposure method that can perform three-dimensional exposure with a short exposure time and can use many of conventional exposure techniques and apparatuses. It is.

A three-dimensional exposure mask and a three-dimensional exposure method that solve the above-described problems have the following characteristics.
That is, as described in claim 1, a three-dimensional exposure mask used when pattern exposure is performed on a material to be exposed formed in a three-dimensional free-form surface, and a microlens array that collects light from a parallel light source; A mask that is arranged along a pattern formed on a material to be exposed and transmits light, and a clad material that is arranged in another portion and shields light from the material to be exposed , and corrects the optical axis. And a holding substrate for holding the mask layer, and a surface facing the material to be exposed is formed into a three-dimensional free-form surface shape corresponding to the shape of the exposed surface of the material to be exposed.
This makes it possible to perform exposure by uniformly irradiating light from a parallel light source for exposure on all parts of the material to be exposed, and only by performing light irradiation from the parallel light source for exposure once. Therefore, it is possible to perform uniform exposure as a whole, and it is possible to easily perform exposure on a material to be exposed having a three-dimensional free-form surface shape in a short time with high quality.
Thereby, the production tact of the exposure process can be shortened compared with the case where exposure is performed by scanning the beam spot with respect to the material to be exposed.
In addition, it is possible to easily manufacture a three-dimensional multilayer substrate by repeatedly performing an exposure process using an exposure method using the present exposure mask.
In addition, when performing exposure using an exposure method using this exposure mask, the planar exposure mask used when exposing a planar shaped exposure material is simply replaced with a three-dimensional free-form curved exposure mask. Other exposure apparatuses such as a parallel light source for exposure and a stepper can use the conventional equipment for the exposed material having a planar shape, thereby reducing the initial investment of the equipment and increasing the maintenance work. There is nothing.

Further, as described in claim 2, the light from the parallel light source is allowed to pass through the exposure mask according to claim 1, and the light is condensed by the microlens array of the exposure mask, and the optical axis is corrected by the mask layer. Then, exposure is performed on a material to be exposed that is disposed close to the exposure mask.
This makes it possible to perform exposure by uniformly irradiating light from a parallel light source for exposure on all parts of the material to be exposed, and only by performing light irradiation from the parallel light source for exposure once. Therefore, it is possible to perform uniform exposure as a whole, and it is possible to easily perform exposure on a material to be exposed having a three-dimensional free-form surface shape in a short time with high quality.
Thereby, the production tact of the exposure process can be shortened compared with the case where exposure is performed by scanning the material to be exposed with a beam spot.
In addition, it is possible to easily manufacture a three-dimensional multilayer substrate by repeatedly performing an exposure process using an exposure method using the present exposure mask.
In addition, when performing exposure using an exposure method using this exposure mask, the planar exposure mask used when exposing a planar shaped exposure material is simply replaced with a three-dimensional free-form curved exposure mask. Other exposure apparatuses such as a parallel light source for exposure and a stepper can use the conventional equipment for the exposed material having a planar shape, thereby reducing the initial investment of the equipment and increasing the maintenance work. There is nothing.

According to the present invention, in all parts of the material to be exposed, it becomes possible to perform exposure by uniformly irradiating light from the parallel light source for exposure, and by performing light irradiation from the parallel light source for exposure only once, The exposure material can be uniformly exposed as a whole, and the exposure of the exposure material having a three-dimensional free-form surface shape can be easily performed in a short time with high quality.
Thereby, the production tact of the exposure process can be shortened, and the production of the three-dimensional multilayer substrate can be easily performed.
In addition, the initial investment of facilities can be suppressed, and the maintenance work can be prevented from increasing.

Next, modes for carrying out the present invention will be described with reference to the accompanying drawings.
A three-dimensional exposure mask 1 shown in FIG. 1 includes a mask layer 3 including a core material 3 a and a cladding material 3 b, a microlens array 2 bonded to one side of the mask layer 3, and a microlens array 2 in the mask layer 3. A holding substrate 4 that holds the mask layer 3 is provided on the surface opposite to the bonding surface.

  As shown in FIG. 2, the microlens array 2 is configured by arranging a plurality of microlenses 2a, 2a,... Formed on a hemispherical lens in a matrix on one surface of the substrate 2b. Each microlens 2a has a characteristic of converging and converging light passing therethrough inward. Note that the microlens 2a is not limited to a hemispherical lens, and may be formed as a lens having another shape such as an aspherical lens.

As shown in FIG. 3, for example, the core material 3a of the mask layer 3 is arranged along a circuit pattern formed on a printed wiring board or the like which is an exposed member, and the clad material 3b is arranged in other portions. Has been.
The core material 3a and the clad material 3b of the mask layer 3 are composed of members having different light refractive indexes, and the refractive index of the clad material 3b is configured to be lower than the refractive index of the core material 3a. . When light enters the core material 3a from the one surface side of the mask layer 3, the light is totally reflected at the boundary between the core material 3a and the clad material 3b and does not leak to the clad material 3b side. Like light, the light exits from the other surface side with little attenuation when passing through the core material 3a.
The holding substrate 4 is made of a resin member or a glass member that transmits light.

A three-dimensional exposure mask 1 configured by laminating a layer of a microlens array 2, a mask layer 3, and a layer of a holding substrate 4 is formed in a three-dimensional free-form surface, for example, as shown in FIG. The three-dimensional exposure mask 1 is composed of a horizontal portion 1a, a first inclined portion 1b, and a second inclined portion 1c.
Here, the light incident on the microlens array 2 travels straight when incident perpendicularly to the surface of the microlens array 2, and when incident from an obliquely inclined direction with respect to the surface of the microlens array 2, Due to the refraction principle of each microlens 2a, the light advances toward the inner side of the lens.

  Accordingly, when the parallel light is irradiated from the upper side to the lower side of the three-dimensional exposure mask 1, the parallel light is incident on the microlens array 2 perpendicularly on the horizontal portion 1a. The light travels downward as it is and enters the core material 3a of the mask layer 3, and further passes through the core material 3a in a direction parallel to the thickness direction of the horizontal portion 1a.

On the other hand, since the 1st inclination part 1b and the 2nd inclination part 1c are inclined, the light which injected into the micro lens array 2 of the 1st inclination part 1b and the 2nd inclination part 1c goes to the inner side of each micro lens 2a. The light is refracted and becomes inclined from the vertical direction to the oblique direction. The inclination direction is a direction in which the thickness direction of the first inclined portion 1b and the second inclined portion 1c and the traveling direction of light approach in parallel.
The light that has passed through the microlens array 2 is incident on the core material 3a of the mask layer 3, but the optical axis is deviated from the direction parallel to the thickness direction of the first inclined portion 1b and the second inclined portion 1c. The incident light is reflected at the boundary surface between the core material 3a and the clad material 3b, the traveling direction (optical axis) is corrected, and the light travels toward the holding substrate 4 side.

In addition, the cause of the optical axis shift includes, for example, variations in focal length and light amount due to manufacturing variations of the microlenses 2a.
Thus, the downward light that has entered the first inclined portion 1b and the second inclined portion 1c exits from the mask layer 3 in a direction substantially parallel to the thickness direction.

Next, an exposure method for a printed wiring board formed in a three-dimensional free-form surface using the three-dimensional exposure mask 1 configured as described above will be described.
As shown in FIG. 4, the printed wiring board 6 includes a horizontal portion 6 a, an inclined portion 6 b that is disposed on one side of the horizontal portion 6 a and is inclined inward, and is disposed on the other side of the horizontal portion 6 a and is inclined inward. In the state shown in FIG. 4, the copper foil 62 is pasted on the entire surface of the base material 61, and the copper 6 Photoresist 7 is applied to the surface of the foil 62.

The three-dimensional exposure mask 1 is disposed close to the upper side of the printed wiring board 6, and the lower surface of the horizontal part 1 a of the three-dimensional exposure mask 1 is formed in accordance with the shape of the upper surface of the horizontal part 6 a of the printed wiring board 6. The lower surface of the inclined portion 1b of the three-dimensional exposure mask 1 is formed in accordance with the shape of the upper surface of the inclined portion 6b of the printed wiring board 6, and the lower surface of the inclined portion 1c of the three-dimensional exposure mask 1 is the inclined portion 6c of the printed wiring board 6. It is formed according to the shape of the upper surface.
That is, the lower surface of the three-dimensional exposure mask 1 facing the upper surface serving as the exposure surface of the printed wiring board 6 that is the material to be exposed is formed into a three-dimensional free-form surface shape corresponding to the shape of the upper surface of the printed wiring board 6. ing.

Thus, with the three-dimensional exposure mask 1 placed close to the upper side of the printed wiring board 6, the exposure parallel light source 8 arranged above the three-dimensional exposure mask 1 is directed to the lower three-dimensional exposure mask 1. When the parallel light is irradiated, the irradiated light is transmitted through the portion of the mask layer 3 where the core material 3a is disposed and irradiated to the photoresist 7, and the portion where the cladding material 3b is disposed is irradiated. The applied light is blocked and the photoresist 7 is not irradiated.
When the printed wiring board 6 is developed after the exposure process of irradiating light from the exposure parallel light source 8, the photoresist 7 in the portion where the core material 3a has been disposed is removed.
Since the core material 3a is arranged along the circuit pattern formed on the printed wiring board 6, the circuit pattern is formed by performing copper plating on the portion where the photoresist 7 is removed.

After the circuit pattern is formed, the remaining photoresist 7 is peeled off, and the copper foil 62 in the portion where the photoresist 7 is peeled off is removed by an etching process, whereby the circuit pattern of the printed wiring board 6 is completed.
Thus, exposure is performed using a three-dimensional exposure mask 1, by performing the formation of the circuit pattern, for example, such as a printed wiring board 6 shown in FIG. 5, a circuit pattern formed surface into a three-dimensional free-form surface The circuit pattern 63 can be formed on the formed printed wiring board.

The aforementioned three-dimensional exposure mask 1 includes a microlens array 2 having a condensing function and a mask layer 3 having an optical axis correcting function, and is formed in a three-dimensional free-form surface shape that matches the shape of the printed wiring board 6. Therefore, in the process of forming a circuit pattern on the printed wiring board 6, when parallel light is irradiated from above the three-dimensional exposure mask 1, the core material 3a disposed on the horizontal portion 3a of the mask layer 3 as described above. Irradiated light travels without being attenuated in a direction substantially parallel to the thickness direction of the mask layer 3 in both the portion and the portion of the core material 3a disposed in the inclined portions 3b and 3c. The photoresist 7 is irradiated.
Thus, it is possible to perform exposure by uniformly irradiating light from the exposure parallel light source 8 on all the horizontal portions 6a and the inclined portions 6b and 6c of the printed wiring board 6.

As described above, by using the three-dimensional exposure mask 1, the printed wiring board 6 can be uniformly exposed as a whole by performing light irradiation from the exposure parallel light source 8 only once. Exposure to the original free-form curved printed wiring board 6 can be easily performed with high quality in a short time.
Thereby, the production tact of the exposure process can be shortened compared with the case where exposure is performed by scanning the printed wiring board with a beam spot.
In addition, it is possible to easily manufacture a three-dimensional multilayer substrate by repeatedly performing an exposure process using an exposure method using the three-dimensional exposure mask 1.
Furthermore, when performing exposure by an exposure method using the present three-dimensional exposure mask 1, the planar exposure mask used when performing exposure on a planar substrate is changed to the present three-dimensional exposure mask 1 having a three-dimensional free-form surface shape. Other exposure apparatuses such as the parallel light source for exposure 8 and the stepper can use the conventional equipment for the flat substrate, so that the initial investment of the equipment is suppressed and the maintenance work is increased. Nor.

Also, an electronic device is usually configured by incorporating a printed wiring board on which electronic components are mounted in a housing or the like. For example, in an electronic device mounted on a vehicle, the interior of a dashboard 9 as shown in FIG. There are things that are stored in.
However, by performing exposure with the present three-dimensional exposure mask 1 and the exposure method, the electronic apparatus can be configured as follows.

  That is, as shown in FIGS. 7 and 8, a three-dimensional exposure mask 1 is formed in accordance with the shape of the back surface of the dashboard 9 formed on the three-dimensional free-form surface, and the dash is formed using the three-dimensional exposure mask 1. The circuit pattern 91 can be directly formed on the back surface of the board 9. In the example shown in FIGS. 7 and 8, connectors 92 are mounted on both ends of each circuit pattern 91, respectively.

  In this way, by forming the circuit pattern 91 directly on the dashboard 9 or the like and mounting the electronic components such as the connector 92, it is possible to omit a printed wiring board or a case that is normally used in an electronic device. It is possible to reduce the size of the device, save space, and reduce the cost.

It is side surface sectional drawing which shows the three-dimensional exposure mask of this invention. It is a perspective view which shows a micro lens array. It is a perspective view which shows a mask layer. It is side surface sectional drawing which shows the state which has arrange | positioned the three-dimensional exposure mask close to the printed wiring board formed in the three-dimensional free-form surface shape, and is irradiated with parallel light. It is a perspective view which shows an example of the printed wiring board which has a three-dimensional free-form surface shape which exposed using the three-dimensional exposure mask and formed the circuit pattern. It is a perspective view which shows the dashboard of a vehicle operation part. It is a back view which shows the dashboard which formed the circuit pattern directly on the back surface. It is AA sectional drawing in FIG.

DESCRIPTION OF SYMBOLS 1 Three-dimensional exposure mask 2 Micro lens array 3 Mask layer 3a Core material 3b Clad material 4 Holding base material 6 Printed wiring board

Claims (2)

A three-dimensional exposure mask used when pattern exposure is performed on a material to be exposed formed in a three-dimensional free-form surface,
A microlens array that collects light from a parallel light source;
A mask that is arranged along a pattern formed on a material to be exposed and transmits light, and a clad material that is arranged in another portion and shields light from the material to be exposed , and corrects the optical axis. Layers,
A holding substrate for holding the mask layer,
A three-dimensional exposure mask characterized in that a surface facing a material to be exposed is formed into a three-dimensional free-form surface shape corresponding to the shape of the exposure surface of the material to be exposed.   The light of a parallel light source is allowed to pass through the exposure mask according to claim 1, the light is condensed by the microlens array of the exposure mask, the optical axis is corrected by the mask layer, and the exposure mask is disposed in proximity to the exposure mask. A three-dimensional exposure method for exposing an exposure material.

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