JP2002158418A - Wiring board and its manufacturing method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To solve the problems of a prior art method for producing a multilayer wiring board that the work is troublesome because process steps of plating, etching, boring a blind hole, and the like, are required, that waste etchant causes environmental pollution, that the wiring cannot be revised after a wiring pattern is formed, once and that the utilization efficiency of resources is low. SOLUTION: A light induced phase transition substance is adopted for a substrate or a wiring part. A multilayer structure composed of a group of such substances having difference phase transition energies is formed on a substrate and an insulated initial state is brought about. A wiring pattern is then irradiated with light and converted into conductors, thus forming conductor wring. In order to return it to the initial state, it is heated and the conductor is converted into an insulator. According to the method, the process is simplified and mass productivity is enhanced significantly. Since the wiring pattern can be altered or modified easily after formation, the resources can be utilized effectively and an environmentally suitable process is obtained because no waste liquid is discharged.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a wiring board having wiring between elements between electronic circuits and electric circuits. In particular, it relates to multilayer wiring means.

[0002]

2. Description of the Related Art The structure of a typical conventional multilayer wiring board is shown in FIG. The conventional manufacturing process will be briefly described with reference to FIG.
The conductive film (mainly copper, Cu) formed thereon is etched to obtain a first layer wiring pattern 302. Next, an insulating layer 303 of an epoxy resin or the like is formed on the wiring pattern by coating or the like, and a blind hole (hole) 304 is formed in a necessary portion by a spot laser or the like to expose the surface of the wiring first layer. A second wiring layer 305 is formed by plating copper or the like on the entire surface and etching the same. At this time, the first and second wiring layers are electrically connected through the blind hole 304. If a multilayer wiring is required, the above steps are repeated.

[0003]

As described in the prior art, in the case of conventional substrate wiring, an etching step is required every time a wiring pattern is provided, and the operation is complicated. This directly leads to a decrease in yield during mass production and an increase in manufacturing cost. In addition, the wet etching method has a problem that a large amount of used etching liquid is generated as waste liquid harmful to the environment. In addition, the conventional multilayer wiring method has a disadvantage that, once the wiring is performed once, as apparent from the process, if the design is changed later, the wiring cannot be redone correspondingly.

The present invention solves these problems,
The conventional board wiring method was completely revised. The adoption of new functional materials simplifies the process, thereby improving the yield during mass production and lowering the manufacturing cost. Further, since there is no wet etching step, the invention does not generate waste liquid and does not pollute the environment. Further, the present invention facilitates these changes and corrections even after a wiring pattern is formed once, and provides a novel environment-compatible process that can use resources significantly more effectively than in the past.

[0005]

This and other objects are achieved by the present invention described below. That is, in the wiring board of the present invention, in a wiring board having wiring between elements (for example, an electronic circuit, an electric circuit, or the like), the wiring portion may be in any of an insulated state, which is a stable state, and a conductor state, which is a metastable state. It is characterized in that it is composed of a light-induced phase change substance that can exist and is in a conductor state. Further, the wiring board of the present invention,
The photo-induced phase change material has a multilayer structure composed of different materials, and each layer has a minimum photo-excitation energy for converting an insulating state into a conductive state, and the lower photo-excitation energy is lower in an upper layer. Further, the wiring board of the present invention has a multi-layer structure in which the photo-induced phase change material is made of a different material, and each layer has a minimum light or heat energy required to insulate a conductive state, and Is characterized in that light or heat energy of the upper layer becomes lower. Further, in the wiring board of the present invention, the insulating state and the conductive state of the photoexcited phase transition material are a stable state and a metastable state having a long life of one year or more, respectively, and take a reversible state by light or heat. It is characterized by obtaining. Further, the wiring board of the present invention is characterized in that one layer made of the photoinduced phase change material is the board itself.

Further, in the method for manufacturing a wiring board according to the present invention, at least (1) the photo-induced phase change material layer in an insulated state is formed by n
A step of forming a layer (n is an integer of 1 or more), and (2) a k-th layer (k is an integer of 1 or more and n or less. The lowermost layer is the first layer, and the uppermost layer is the nth layer. Indicates that the wiring pattern of k = 1) is not less than the lowest excitation energy for the photo-induced phase change material constituting the k-th layer and that k> 1 is the minimum excitation energy for the photo-induced phase change material constituting the (k-1) -th layer. (3) externally applying energy less than the energy for insulating the k-th layer and greater than or equal to the insulating energy for the (k + 1) -th layer, by irradiation with light having energy less than the excitation energy; 4) a step of repeating the steps (2) to (3) up to the n-th layer (uppermost layer) by replacing k with (k + 1). Further, the method for manufacturing a wiring board according to the present invention is characterized in that: (1) a k-th layer (k is an integer of 1 or more and n or less; a lowermost layer is a first layer; Forming an upper layer as an n-th layer, an initial value is k = 1), and (2) a k-th layer.
When the wiring pattern of the layer is equal to or more than the minimum excitation energy for the photo-induced phase change material constituting the k-th layer and k> 1, the energy is less than the minimum excitation energy for the photo-induced phase change material constituting the (k-1) -th layer. And (3) repeating the steps (1) and (2) in order from k to (k + 1) until the n-th layer (uppermost layer). And Further, the method of manufacturing a wiring board according to the present invention is characterized in that, in the step of converting the photo-induced phase change substance into a conductor using light, the wiring pattern is formed using a mask or directly by laser scanning irradiation.

[0007]

The following is a description of a photo-induced phase change material used for a wiring portion in an electronic substrate, which is a feature of the present invention.

In the present invention, the material used for the wiring portion is mainly composed of a transition metal or an oxide thereof which undergoes a phase transition when irradiated with light or heated. As the transition metal oxide, a general formula Ax ByO
z (where x, y, and z are 1 ≦ x ≦ 14, 1 ≦
y ≦ 24, 1 ≦ z ≦ 41, and A and B may be the same element or different elements). It is considered that the energy state of the atomic system of such a transition metal oxide is changed by light irradiation, the crystal lattice is displaced, and a phase transition phenomenon is caused based on the displacement.

[0009] Such transition metal oxide, the crystal structure is not particularly limited, and a A ions with a + charge on the crystal structure -X - ^{-A +} -X - ^(X
= O, BOx), and this one-dimensional (straight line)
A low-dimensional oxide whose structure is characterized by physical properties is preferred.
This is because it is preferable that the displaced lattice atoms are softly bonded to the lattice, that is, the energy of the lattice strain due to the displacement is smaller, and it is generally considered that a low-dimensional substance has a soft lattice.

An example of such a low-dimensional substance is a delafossite-type oxide represented by the general formula ABO ₂ . In the delafossite-type oxide, the above-mentioned low-dimensional structure has a simple chain-order structure represented by-(BO ₂ ) ^-- A ⁺ -(BO ₂ ) ^-- . Such a simple structure is considered to have an effect of further enhancing the softness of the lattice, which is a characteristic of a low-dimensional substance, and has a characteristic that the response speed of light-induced phase transition is extremely high. Furthermore, the delafossite-type oxide has an advantage that its simple low-dimensional structure allows a small adjustment of the band gap that determines the energy required for the photoinduced phase transition. The band gap is the lowest photon energy at which a light-induced phase transition occurs. If the band gap is small, it becomes possible to cause phase transition even with lower energy light, for example, laser light having a wavelength in the infrared region as well as in the visible / ultraviolet region, and the range of light source choices is greatly expanded.

[0011] The light-induced phase transition means that the system is excited by light energy incident on a solid to change an electronic state, thereby causing a lattice displacement. Of the changes in the physical properties of the material caused by such lattice displacement, especially the property that the electrical conductivity changes dramatically,
That is, it is a feature of the present invention that attention is paid to the property that the conductor state and the insulation state can be controlled by light irradiation and heating temperature change, and this is positively used for a wiring portion in the electronic board. Incidentally, the physical properties of the solid crystal which reversibly change include an absorption spectrum, a dielectric constant, a refractive index, a reflectance, a magnetic property, and the like in addition to the electric conductivity.

By utilizing the change in electric conductivity due to light, it is possible to control reversible phase transition between each other, such as converting an insulator into a conductor or returning the conductor to an insulator. Here, “conducting” means closing a band gap between a valence band and a conduction band filled with an insulator by photoexcitation. In other words, the size of the Brillouin region is doubled by light, and the valence band and the conduction band are coupled. For this purpose, it is only required that the length of the repetition period of the insulator lattice can be reduced to half by light. For example, at a certain temperature or lower, a conductor in which electrons are occupied in half of the band becomes a Peierls insulator because the lattice period a of the conductor becomes 2a due to the lattice displacement and the localization of electrons, and therefore the wave number π / 2a This is because there is a gap in The reverse process is performed by irradiating light, halving the lattice period of the Peierls insulator, and spreading localized electrons uniformly in the crystal, the band gap of the insulator becomes a closed conductor. be able to. Further, the direction of the phase change can be reversed depending on the material design. That is,
The conductor can be insulated by irradiating the conductor with light. Such bidirectional phase transition is possible only by light irradiation, but the effect of heat may be used together. When a laser is used as the light source, the wavelength (energy) of the laser is used when the insulator is converted into a conductor, and the power (heat) of the laser is used when the conductor is returned to the insulator.

Finally, a supplementary note is made on bistability. The term “bistability” as used herein refers to the time required for a transition from a stable state to a metastable state based on a change in the lattice due to light irradiation or the like, and for returning to the original stable state even if the light is extinguished here. (Relaxation time) means very long (for example, one year or more). The time during which the metastable state is maintained, that is, the life can be freely controlled depending on the material design.

[0014]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The details of the present invention will be described below based on some embodiments.

(Embodiment 1) Among the substances belonging to delafossite described in the operation, the phase transition from an insulating state to a conductive state occurs at a wavelength of 700 nm or less, and from the conductive state to the original insulating state by heating at 600 ° C. or more. Substance 11 which undergoes a phase transition, wavelength 720
The phase transition from the insulating state to the conductive state occurs at 580 ° C.
The substance 12 undergoes a phase transition from the conductor state to the original insulation state by the above heating, and the phase transition from the insulation state to the conductor state at a wavelength of 740 nm or less, and the phase from the conductor state to the original insulation state by heating at 560 ° C. or more. The substance 13 that undergoes a transition and the substance 1 that undergoes a phase transition from an insulating state to a conducting state at a wavelength of 760 nm or less, and undergoes a phase transition from the conducting state to the original insulating state by heating at 540 ° C. or more.
4 were prepared and subjected to the following experiment of this example. Substance 11
14 to 14 are insulating states which are stable states in an initial state, and a conductor state which is a metastable state has a sufficiently long life and can be regarded as a substantially bistable substance. The term "life" as used herein refers to a period required until the electric conductivity in the conductor state becomes half the initial value.

On the surface of the glass epoxy substrate 10, a layer 21 composed of the substance 11 and having a thickness of 0.3 mm was formed. On the upper surface of the layer 21, a thickness of 0.
A layer 22 having a thickness of 3 mmt was formed, and layers 23 and 24 made of the substance 13 and the substance 14 were similarly laminated with a thickness of 0.3 mmt. Thus, a laminated film sample was obtained on the silicon substrate. A metal mask cut out from an elongated rectangular pattern was prepared, adhered to the upper surface of the layer 24, and parallel light having a wavelength of 720 nm was irradiated from above on the substrate in the vertical direction. At this time, the layer 2 composed of the substance 11
1 retains the insulating state without causing a phase transition,
The phase transitions to a conductor state according to the mask pattern. Thereafter, the sample is heated at 560 ° C. Then layer 22
Is maintained, but the layers 23 and 24 also undergo a phase transition to the initial state (stable state). The metal mask was shifted by 90 degrees, the cutout pattern was arranged so as to be orthogonal to the conventional one, and the substrate was irradiated with parallel light having a wavelength of 760 nm from above the layer 24 in the vertical direction. As a result, only the layer 24 undergoes a phase transition to a conductor state along the mask pattern. The conductor wiring pattern obtained by this series of operations is as shown in the plan view shown in FIG. 1A and the hatched portion in the cross-sectional view shown in FIG.

In the conductive state pattern orthogonal to the insulating layer 23 as described above, the conduction was examined by applying an electrode from the cross section of the sample laminated portion.
It was confirmed that a low-resistance wiring was obtained along the hatched portion in (b).

Further, when it is desired to change the conductor wiring pattern, it is easy to understand that a new wiring pattern can be constructed again by heating the sample to 600 ° C. or higher to return all the layers to the insulating state once and following the procedure of this embodiment. it can.

In this embodiment, the substances 11 to 14 having different phase transition energies are used for explanation, but the present invention is not limited to these four kinds of substances. In addition, the substances 11 to 14 have an extremely long lifetime of one year or more in a conductor state that is a metastable state. When it is necessary to maintain the wiring pattern for a long period of time, it is desirable that the multi-layer wiring portion be formed of such a long-lived (one year or more) substance, that is, a group of substances that can be regarded as bistable.

(Embodiment 2) Among the substances belonging to delafossite described in the operation, a phase transition from an insulating state to a conductive state occurs at a wavelength of 700 nm or less, and from a conductive state to an original insulating state by heating at 600 ° C. or more. Substance 11 which undergoes a phase transition, wavelength 720
The phase transition from the insulating state to the conductive state occurs at 580 ° C.
The substance 12 undergoes a phase transition from the conductor state to the original insulation state by the above heating, and the phase transition from the insulation state to the conductor state at a wavelength of 740 nm or less, and the phase from the conductor state to the original insulation state by heating at 560 ° C. or more. The substance 13 that undergoes a transition and the substance 1 that undergoes a phase transition from an insulating state to a conducting state at a wavelength of 760 nm or less, and undergoes a phase transition from the conducting state to the original insulating state by heating at 540 ° C. or more.
4 were prepared and subjected to the following experiment of this example. Substance 11
14 to 14 are insulating states which are stable states in an initial state, and a conductor state which is a metastable state has a sufficiently long life and can be regarded as a substantially bistable substance. The term "life" as used herein refers to a period required until the electric conductivity in the conductor state becomes half the initial value.

On the surface of the glass epoxy substrate 10, a layer 21 made of the substance 11 and having a thickness of 0.3 mm was formed. On the upper surface of the layer 21, a thickness of 0.
A layer 22 having a thickness of 3 mmt was formed, and layers 23 and 24 made of the substance 13 and the substance 14 were similarly laminated with a thickness of 0.3 mmt. Thus, a laminated film sample was obtained on the silicon substrate. 0.1mm diameter from the top of the sample, wavelength 720n
FIG. 1 (a) by irradiating a laser beam of m
Was scanned between AB shown in the plan view of FIG. . At this time, the layer 21 made of the substance 11 does not undergo a phase transition and maintains an insulating state, but the layers 22 to 24 undergo a phase transition to a conductor state according to a linear pattern scanned by a laser. Thereafter, the sample is heated at 560 ° C. Then, the conductor state of the layer 22 is maintained, but the layers 23 and 24 also undergo a phase transition to the initial state (stable state). Subsequently, the diameter is 0.1 mm, the wavelength is 760 nm.
Laser irradiation was performed while scanning in the vertical direction with respect to the previous scanning using the laser. This resulted in a phase transition to the conductor state along the miracle of scanning only layer 24. The conductor wiring pattern obtained by this series of operations is as shown in the plan view shown in FIG. 1A and the hatched portion in the cross-sectional view shown in FIG.

In the conductive state pattern orthogonal to the insulating layer 23 as described above, the conduction was examined by applying an electrode from the cross section of the sample laminated portion.
It was confirmed that a low-resistance wiring was obtained along the hatched portion in (b).

Further, when it is desired to change the conductor wiring pattern, it is easy to understand that a new wiring pattern can be constructed again by heating the sample to 600 ° C. or higher to return all the layers to the insulating state once and following the procedure of this embodiment. it can.

As in this embodiment, by scanning the photo-induced phase change material layer along an arbitrary curve with a laser having a fine aperture, a multilayer conductor wiring can be formed by a simple method without using a mask. It has been found.

In the present embodiment, substances 11 to 14 having different phase transition energies are used for explanation, but the present invention is not limited to these four kinds of substances. In addition, the substances 11 to 14 have an extremely long lifetime of one year or more in a conductor state that is a metastable state. When it is necessary to maintain the wiring pattern for a long period of time, it is desirable that the multi-layer wiring portion be formed of such a long-lived (one year or more) substance, that is, a group of substances that can be regarded as bistable.

(Embodiment 3) Of the substances belonging to delafossite described in the operation, a substance 41 which undergoes a phase transition from an insulating state to a conducting state at a wavelength of 700 nm or less, and a phase transition from an insulating state to a conducting state at a wavelength of 720 nm or less. And a substance 43 that undergoes a phase transition from an insulating state to a conductive state at a wavelength of 740 nm or less, and a substance 44 that undergoes a phase transition from an insulating state to a conductive state at a wavelength of 760 nm or less. did. Each of the substances 41 to 44 is in an insulating state, which is a stable state in the initial state, and a conductor state, which is a metastable state, has a sufficiently long life and can be regarded as a substantially bistable substance. The term "life" as used herein refers to a period required until the electric conductivity in the conductor state becomes half the initial value.

The thickness of the material 41 is 0.3 mm.
t, a substrate 51 is prepared, and the substance 42 is provided on the surface of the substrate 51.
The layer 52 having a thickness of 0.3 mmt was formed. Here, a metal mask from which an elongated rectangular pattern was cut out was prepared and adhered to the upper surface of the layer 52, and parallel light having a wavelength of 720 nm was irradiated from above on the substrate in the vertical direction. At this time, the layer 51 made of the substance 41 does not undergo a phase transition and maintains an insulating state, but only the layer 52 undergoes a phase transition to a conductive state according to the mask pattern. Thereafter, a layer 5 of 0.3 mmt thickness composed of the substance 43 is formed.
3 was formed. Here, irradiation was performed in the vertical direction of the substrate by using a parallel light having a wavelength of 740 nm and applying an appropriate mask. At this time, only the layer 53 where the phase transition occurs at the lowest energy at this time becomes conductive in the exposed portion exposed. Finally, the material 44 is similarly formed on the top layer with a thickness of 0.3 mm.
t was provided (layer 54), and a similar conductive treatment was performed. The conductor wiring pattern obtained by this series of operations is shown in FIG.
2B and the cross-sectional view shown in FIG. 2B.

The conduction state of the conductor pattern including the short circuit between the different layers 52 and 54 via the layer 53 was examined by applying an electrode to the cross section of the sample stacking section. It was confirmed that a low-resistance wiring was obtained along the hatched portions of (a) and (b). Here, it has been shown that the electrical conduction between the different layers does not require the step of forming a blind hole as in the prior art, and the electrical connection between the different layers can be obtained by a simple method.

In the method according to the present embodiment, unlike the first and second embodiments, it is not always possible to change the wiring pattern. Since the conditions required for the phase transition are not required, there is a feature that the degree of freedom in material selection is large.

In the present embodiment, the substances 41 to 44 having different phase transition energies are used for explanation, but the present invention is not limited to these four kinds of substances. In addition, the substances 41 to 44 have a very long lifetime of one year or more in a conductor state that is a metastable state. When it is necessary to maintain the wiring pattern for a long period of time, it is desirable that the multi-layer wiring portion be formed of such a long-lived (one year or more) substance, that is, a group of substances that can be regarded as bistable.

In this embodiment, the substrate itself is also made of a photo-induced phase change material. It is obvious that an arbitrary one-dimensional wiring pattern can be formed even with the substrate alone. In this case, the conductive portion may also be exposed on the back surface of the substrate (the surface opposite to the light irradiation surface). In this case, when the back surface is covered with an insulating film such as a resin, or when the substrate is fixed on an arbitrary curved surface. An insulating spacer or the like may be used. As another method, by adjusting the power of light used in the conductive step, only the vicinity of the surface of the light irradiation surface of the substrate can be made conductive in a desired pattern, and the back surface can be kept in an insulated state. .

(Embodiment 4) Of the substances belonging to delafossite described in the operation, a substance 41 which undergoes a phase transition from an insulating state to a conducting state at a wavelength of 700 nm or less, and a phase transition from an insulating state to a conducting state at a wavelength of 720 nm or less. And a substance 43 that undergoes a phase transition from an insulating state to a conductive state at a wavelength of 740 nm or less, and a substance 44 that undergoes a phase transition from an insulating state to a conductive state at a wavelength of 760 nm or less. did. Each of the substances 41 to 44 is in an insulating state, which is a stable state in the initial state, and a conductor state, which is a metastable state, has a sufficiently long life and can be regarded as a substantially bistable substance. The term "life" as used herein refers to a period required until the electric conductivity in the conductor state becomes half the initial value.

The thickness of the material 41 is 0.3 mm.
t, a substrate 51 is prepared, and the substance 42 is provided on the surface of the substrate 51.
The layer 52 having a thickness of 0.3 mmt was formed. Here, a laser having a diameter of 0.1 mm and a wavelength of 720 nm was irradiated on the substrate in the vertical direction, and a proper distance scan was performed on a straight line. At this time, the layer 51 composed of the substance 41 does not cause a phase transition and maintains an insulating state, but only the layer 52 undergoes a phase transition to a conductor state according to a miracle of laser scanning. Thereafter, a layer 53 made of the substance 43 and having a thickness of 0.3 mmt was formed. Here, irradiation was performed along an appropriate pattern using laser light having a wavelength of 740 nm. At this time, only the layer 53 where the phase transition occurs with the lowest energy at this time is made conductive in the laser irradiation part. Finally, the material 44 was similarly provided on the uppermost layer with a thickness of 0.3 mmt (layer 54), and a similar conductive treatment was performed by laser scanning. The conductor wiring pattern obtained by this series of operations is as shown by the hatched portion in the plan view shown in FIG. 2A and the cross-sectional view shown in FIG. 2B.

The conduction state of the conductor pattern including the short-circuit between different layers of the layers 52 and 54 via the layer 53 was examined by applying an electrode to the cross section of the sample laminated portion. It was confirmed that a low-resistance wiring was obtained along the hatched portions of (a) and (b). Here, it has been shown that the electrical conduction between the different layers does not require the step of forming a blind hole as in the prior art, and the electrical connection between the different layers can be obtained by a simple method.

In the method of the present embodiment, unlike in the first and second embodiments, it is not always possible to change the wiring pattern. Since the conditions required for the phase transition are not required, there is a feature that the degree of freedom in material selection is large. In addition, since the method does not use a mask, it is effective in simplifying the manufacturing process.

In the present embodiment, the substances 41 to 44 having different phase transition energies are used for explanation, but the present invention is not limited to these four kinds of substances. In addition, the substances 41 to 44 have a very long lifetime of one year or more in a conductor state that is a metastable state. When it is necessary to maintain the wiring pattern for a long period of time, it is desirable that the multi-layer wiring portion be formed of such a long-lived (one year or more) substance, that is, a group of substances that can be regarded as bistable.

In this embodiment, the substrate itself is also made of a photo-induced phase change material. It is obvious that an arbitrary one-dimensional wiring pattern can be formed even with the substrate alone. In this case, the conductive portion may also be exposed on the back surface of the substrate (the surface opposite to the light irradiation surface). In this case, when the back surface is covered with an insulating film such as a resin, or when the substrate is fixed on an arbitrary curved surface. An insulating spacer or the like may be used. As another method, by adjusting the power of light used in the conductive step, only the vicinity of the surface of the light irradiation surface of the substrate can be made conductive in a desired pattern, and the back surface can be kept in an insulated state. .

[0038]

According to the conventional method of manufacturing a wiring board, an etching step is required every time one wiring pattern is provided, the operation is complicated, and the used etching waste liquid pollutes the environment. Further, in the conventional method, once the wiring pattern is formed, the wiring cannot be redone.

According to the present invention, the process can be simplified by using a photo-induced phase change material for the wiring board, thereby improving the yield during mass production and reducing the manufacturing cost. Since there is no etching step as described above, there is an effect that waste liquid is not discharged and the environment is not polluted. The present invention, in which these changes and corrections can be easily performed even after a wiring pattern has been formed once, greatly contributes to the effective use of resources and the like that has been required in recent years.

[Brief description of the drawings]

FIG. 1 is a diagram showing the formation of a two-layer conductive path using the photoinduced phase change material of the present invention. (A) Plan view. (B) Sectional view.

FIG. 2 is a diagram showing a state in which the two-layer conductive paths of the present invention are short-circuited by a conductor state of a photo-induced phase change substance. (A) Plan view.
(B) Sectional view.

FIG. 3 is a cross-sectional view of a conventional multilayer wiring board.

[Explanation of symbols]

10. Glass epoxy substrate 21. First layer composed of photoinduced phase change material 11 22. 22. Second layer composed of photoinduced phase change material 12 13. Third layer composed of photoinduced phase change material 13 4. fourth layer composed of photoinduced phase change material 14 34. Second-layer conductive portion made of light-induced phase change material 12 51. Fourth-layer conductive portion made of photoinduced phase change material 14 First layer made of photoinduced phase change material 41 52. Second layer composed of photoinduced phase change material 42 53. Third layer composed of photoinduced phase change material 43 54. Fourth layer made of photoinduced phase change material 44 62. 63. Second-layer conductive portion made of photoinduced phase change material 42 64. Third-layer conductive portion made of light-induced phase change material 43 301. Fourth-layer conductive portion made of photoinduced phase change material 44 Insulating substrate 302. First wiring layer 303. Insulating layer 304. Blind hole 305. Second wiring layer

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Masato Kakihana 6-1 Espoir Aobadai Aobadai C-603 F-term (reference) 4E351 AA01 AA07 BB01 BB24 BB26 BB29 BB46 CC27 DD31 GG20 5E317 AA24 BB01 BB04 BB30 CC53 CD40 GG20 5E346 AA15 CC04 CC09 CC31 HH32

Claims (10)

[Claims] 1. A wiring board having a wiring between elements, wherein a wiring portion is made of a conductor made of a photo-induced phase transition material that can exist in any of a stable insulating state and a metastable conductive state. A wiring board characterized by being configured in a state. 2. The photo-induced phase transition material has a multilayer structure composed of different materials, and each layer has a minimum photo-excitation energy for converting an insulating state into a conductive state, and the lowest photo-excitation energy is lower in an upper layer. The wiring board according to claim 1, wherein 3. The light-induced phase change material has a multilayer structure composed of different materials, and each layer has a minimum light or heat energy required to insulate a conductive state, and the minimum light or heat energy is present. 3. The wiring board according to claim 2, wherein the energy is lower in the upper layer. 4. The photo-induced phase change material according to claim 1, wherein the insulated state, which is a stable state, and the conductor state, which is a meta-stable state, can be reversibly phase-changed by light or heat to be in a mutual state. The wiring board according to claim 1. 5. The method according to claim 1, wherein the life of the conductor state in the metastable state, that is, the time required for the electric conductivity of the conductor state to become half of the initial value, is one year or more. Item 5. The wiring board according to item 4. 6. The wiring substrate according to claim 4, wherein one layer of the photo-induced phase change material is a substrate itself. 7. The method for manufacturing a wiring board according to claim 5, wherein at least (1) a step of forming an n-layer (n is an integer of 1 or more) of a photoinduced phase change material layer in an insulating state; 2) The k-th layer (k is an integer of 1 or more and n or less. The lowermost layer is the first layer, and the uppermost layer is the n-th layer. The initial value is k =
The wiring pattern of 1) is set to have a minimum excitation energy not less than the minimum excitation energy for the photo-induced phase change material constituting the k-th layer and less than the minimum excitation energy for the photo-induced phase change material constituting the (k-1) -th layer when k> 1. (3) applying external energy less than the energy for insulating the k-th layer and greater than or equal to the insulating energy for the (k + 1) -th layer; (2) to (3), wherein k is replaced by (k + 1) and the process is sequentially repeated up to the n-th layer (uppermost layer). 8. The n-layer wiring according to claim 5, wherein n is 1
In the method of manufacturing a substrate, at least (1) a k-th layer (k is an integer of 1 or more and n or less; a lowermost layer is a first layer, and a lowermost layer is a first layer; And (2) setting the wiring pattern of the k-th layer to a value not less than the lowest excitation energy for the photo-induced phase change material constituting the k-th layer and k
When> 1, a step of converting the photo-induced phase change material constituting the (k-1) -th layer into a conductor by irradiating light having energy less than the lowest excitation energy to the (k-1) layer; and (3) the steps (1) to (2) A process in which k is replaced with (k + 1) and the process is sequentially repeated up to the n-th layer (uppermost layer). 9. The method for manufacturing a wiring board according to claim 7, wherein the wiring pattern is formed using a mask in the step of converting the photo-induced phase change substance into a conductor using light. 10. A process for forming a wiring by directly scanning and irradiating a laser along a previously designed wiring pattern without using a mask in a step of converting a photo-induced phase change material into a conductor using light. Item 7. The method for manufacturing a wiring board according to Item 7 or 8.