JPWO2020031521A1 - Wiring board and its manufacturing method - Google Patents

Abstract

The simple structure of the wiring board ensures the functionality of the encapsulating resin and improves reliability. The wiring board includes a through hole penetrating the base material and a conductor formed along the side wall of the through hole. In this wiring board, a plurality of types of insulators are filled inside the conductor formed along the side wall of the through hole. Of the plurality of types of insulators, a specific type of insulator can have higher adhesion than other types of insulators. Other types of insulators can have a lower coefficient of expansion than certain types of insulators. By filling a plurality of types of insulators in this way, the functionality of the encapsulating resin is ensured.

Description

The present technology relates to a wiring board. More specifically, the present invention relates to a wiring board having holes penetrating the base material and a method for manufacturing the same.

In recent years, semiconductor devices using semiconductor chips and external connection devices have been used in many products such as electronic devices and automobiles. As these products become more sophisticated, smaller, and lighter, semiconductor devices are required to be smaller, have more pins, and have finer pitches for external connection terminals. Conventionally, as a material for a semiconductor substrate, an organic material such as an epoxy resin and a glass fiber impregnated with the epoxy resin has been widely used. Most of these organic materials have a relatively high water absorption rate, and shrinkage and expansion due to temperature are larger than those of silicon semiconductor chips. Therefore, fine wiring that is scale-matched with the semiconductor chip is formed. Was difficult. In addition, there is a problem in ensuring reliability after connecting to a semiconductor chip.

Therefore, silicon and glass are attracting attention as semiconductor substrate materials instead of organic materials. Since these have greatly reduced moisture absorption and expansion / contraction due to temperature as compared with organic materials, they have great merits in terms of formation of fine wiring and connection reliability with semiconductor chips.

Comparing the two, a substrate made of silicon can form finer wiring than a glass substrate by utilizing the know-how of semiconductor chip manufacturing, and further silicon via (TSV: Through-Silicon-Via) is formed. It has the advantage that the process is also established. On the other hand, the shape of silicon is limited to the disk type, the peripheral portion of the wafer cannot be used, and it is difficult to manufacture in a large size. On the other hand, glass substrates can be increased in size by utilizing know-how in display materials, etc., while the manufacturing process has not yet been established. Furthermore, considering the comparison in terms of electrical characteristics, it can be said that the silicon substrate is a semiconductor, whereas the glass substrate is an insulator, so there is no concern about the occurrence of parasitic capacitance even in a high-speed transmission circuit, and the electrical characteristics are better. .. In the first place, in the case of a glass substrate, since the step itself of forming an insulating film on the surface thereof is unnecessary, the insulation reliability is essentially high, and it is also advantageous in terms of shortening the step.

As described above, the glass substrate has many advantages, but there is a problem that the manufacturing process has not yet been sufficiently established. In particular, due to its brittleness, it is difficult to form through electrodes (TGV: Through-Glass-Via) required for electrical conduction of the surface, and the adhesion with copper, which is the mainstream of wiring materials, is weak. Therefore, there is a problem that the certainty of wiring formation is not high.

In such a glass substrate, in order to improve the connection reliability between the front and back surfaces of the glass substrate and the conductive layer in the through hole, the encapsulating resin is dented so that the via wiring portion and the front and back wiring portions are connected to each other. A wiring board having a wide contact area has been proposed (see, for example, Patent Document 1).

JP-A-2017-228727

In the above-mentioned conventional technique, peeling between the wirings is suppressed by widening the contact area between the via wiring portion and the front and back wiring portions. However, in the above-mentioned conventional technique, there are problems that the number of steps for providing dents is increased, the amount of dents is difficult to control, and the yield is lowered.

This technology was created in view of such a situation, and aims to secure the functionality of the encapsulating resin by a simple structure in the wiring board and improve the reliability.

The present technology has been made to solve the above-mentioned problems, and the first side surface thereof is a base material, a hole penetrating the base material, and a conductor formed along the side wall of the hole. It is a wiring board including a plurality of types of insulators filled inside the conductor. As a result, a plurality of types of insulators are filled inside the through holes, and the properties of each insulator are exhibited.

Further, in the first aspect, the specific type of insulator among the above-mentioned plurality of types of insulators has higher adhesion than the other types of insulators, and the above-mentioned other types of insulators have the above-mentioned specific types. An insulator having a coefficient of expansion lower than that of the type of insulator may be used. This brings about the effect of demonstrating the properties of both insulators, such as high adhesion and low expansion coefficient.

Further, in this first aspect, the particular type of insulator may cover the conductor, and the other type of insulator may be formed inside the conductor. This has the effect of reducing the effect of expansion while ensuring adhesion to the conductor.

Further, on the first side surface, the particular type of insulator may include a portion inside the conductor which is connected to each other in the pore diameter direction.

Further, in this first aspect, the area ratio of the particular type of insulator to the other type of insulator in the pore diameter direction may be changed with respect to the penetration direction.

Further, in this first aspect, the other type of insulator may include a type of granular insulator different from the above-mentioned specific type of insulator.

Further, in the first aspect, the specific type of insulator is a granular insulator, and the other type of insulator may be filled in the gaps between the granular insulators. This brings about the effect of reducing the influence of expansion while ensuring the adhesion with the conductor by the granular insulator.

Further, on the first side surface, the granular insulator may have a state of being deformed along the shape of the conductor at a contact portion with the conductor, and may be different from other granular insulators. It may have a state of being deformed along the shape of each other at the contact portion of the above. This has the effect of reducing the effect of expansion while ensuring adhesion.

Further, on the first side surface, another conductor that closes one opening of the penetrating hole may be further provided. That is, it may be applied to a bottomed via structure.

Further, in this first aspect, the base material may be silicon or glass. Although these are materials having a low coefficient of linear expansion, they have the effect of adjusting the affinity between the base material and the insulator by filling the inside of the through holes with a plurality of types of insulators.

Further, the second side surface of the present technology is a step of attaching a sheet material made of a plurality of types of insulators to at least one surface of a base material having a through hole and a conductor formed along the side wall of the hole. , A method of manufacturing a wiring board including a step of applying pressure under vacuum to fill the inside of the conductor with the sheet material. This brings about the effect of filling a plurality of types of insulators by a simple method.

Further, the third side surface of the present technology is to provide a plurality of types of insulators including a granular insulator from one surface of a base material having a through hole and a conductor formed along the side wall of the hole. It is a method of manufacturing a wiring board including a step of supplying the inside of the base material and a step of applying pressure from one surface of the base material to the plurality of types of insulators inside the conductor. This brings about the effect of filling a plurality of types of insulators by a simple method.

According to this technique, it is possible to obtain an excellent effect that the functionality of the encapsulating resin can be ensured by a simple structure in the wiring board and the reliability can be improved. The effects described here are not necessarily limited, and may be any of the effects described in the present disclosure.

It is sectional drawing which shows the structural example of the wiring board 10 in the 1st Embodiment of this technique. It is a process drawing which shows an example of the manufacturing method of the wiring board 10 in the 1st Embodiment of this technique. It is sectional drawing which shows the other structural example of the wiring board 10 in the 1st Embodiment of this technique. It is sectional drawing which shows the further structural example of the wiring board 10 in the 1st Embodiment of this technique. It is a figure which shows the structural example of the wiring board 10 in the 2nd Embodiment of this technique. It is a process drawing which shows an example of the manufacturing method of the wiring board 10 in the 2nd Embodiment of this technique. It is sectional drawing which shows the other structural example of the wiring board 10 in the 2nd Embodiment of this technique. It is sectional drawing which shows the further structural example of the wiring board 10 in the 2nd Embodiment of this technique. It is a process drawing which shows the 1st modification of the manufacturing method of the wiring board 10 in embodiment of this technique. It is a process drawing which shows the 2nd modification of the manufacturing method of the wiring board 10 in embodiment of this technique.

Hereinafter, embodiments for carrying out the present technology (hereinafter referred to as embodiments) will be described. The explanation will be given in the following order.
1. 1. First Embodiment (Example of using a photosensitive sheet resist as a filling material)
2. Second embodiment (example using insulating particles as filling material)
3. 3. Deformation example (example using laser aperture processing)

<1. First Embodiment>
[Structure of wiring board]
FIG. 1 is a cross-sectional view showing a structural example of the wiring board 10 according to the first embodiment of the present technology.

The wiring board 10 assumes a material having a low coefficient of thermal expansion (CTE) such as glass or silicon as the base material 100. The wiring board 10 includes a through hole (via) 110 penetrating from the front surface to the back surface of the base material 100.

Inside the through hole 110, a conductor 120 is formed along the side wall. As the conductor 120, for example, a conductive metal such as copper (Cu) is used. The conductor 120 is formed as a copper film by, for example, forming a copper sputter film by full surface sputtering and immersing it in a plating solution to grow it.

When a material having a low coefficient of linear expansion is used as the base material 100, when a standard resin is embedded in the through hole 110, the wiring is stress-damaged due to the difference in the coefficient of linear expansion, and poor continuity occurs. There is a risk. Therefore, the inside of the conductor 120 of the through hole 110 is filled with a plurality of types of insulators. That is, the wiring board 10 of the first embodiment includes a multiple structure in which a resin is embedded in a through hole 110 in a coaxial shape.

In this example, two types of insulators 210 and 220 are shown. As the particular type of insulator 210, one having higher adhesion than the other types of insulator 220 is adopted. As the other type of insulator 220, one having a lower expansion rate than that of a specific type of insulator 210 is adopted. As a result, the insulator 210 can enhance the functionality such as wiring adhesion and the dielectric constant, while the insulator 220 can have the effect of stress relaxation and the like. Then, while maintaining high reliability, it is possible to increase the degree of freedom in via design, transmission characteristics, and the like.

In this first embodiment, it is assumed that a photosensitive sheet resist having a two-layer structure of insulators 210 and 220 is encapsulated in the through hole 110 by a vacuum laminating method.

In the figure, a shows an example in which the inner insulator 220 is divided by the outer insulator 210. That is, the particular type of insulator 210 includes a portion inside the conductor 120 that is connected to each other in the hole diameter direction of the through hole 110.

On the other hand, b in the figure shows an example in which the inner insulator 220 is not divided by the outer insulator 210. That is, the other type of insulator 220 includes a portion inside the conductor 120 that is connected to each other in the penetration direction (depth direction) of the through hole 110.

In this first embodiment, the insulators 210 and 220 can assume any of the states a and b in the figure. In either case, the insulator 210 covers the conductor 120, and the insulator 220 is formed inside the conductor 120.

The ratio of the cross-sectional area of the outer insulator 210 to the inner insulator 220 in the pore radial direction changes with respect to the penetration direction (depth direction). That is, as shown in a and b in the figure, the areas of the insulators 210 and 220 are not uniform.

Although one wiring board 10 is shown in this example, the wiring board 10 may be used as a part of the laminated board by laminating with another wiring board.

[Manufacturing method of wiring board]
FIG. 2 is a process diagram showing an example of a manufacturing method of the wiring board 10 according to the first embodiment of the present technology.

As shown in a in the figure, a photosensitive sheet resist having a two-layer structure of insulators 210 and 220 is bonded to the front surface and the back surface of the base material 100. At that time, the front and back surfaces of the photosensitive sheet resist are determined so that the insulator 210 having high adhesion comes into contact with the base material 100.

As shown in b in the figure, a pressure is applied by raising the temperature under vacuum in a state where the photosensitive sheet resist is bonded (vacuum laminating method). As a result, the insulators 210 and 220 forming the photosensitive sheet resist are encapsulated in the through holes 110.

After that, unnecessary portions are removed by lithography and development processing to obtain the multiple structure shown in c in the figure.

An example of the insulator 220 filled in the central portion of the through hole 110 is a silicon-based stress relaxation material. Specific product names include "one-component elastomer type JCR6101 UP" (Toray Industries, Inc.). In the case of this specification, CTE: 300 ppm and Young's modulus: about 1.2 MPa. It is assumed that the insulator 220 is laminated with the insulator 210, processed into a film, and simultaneously filled by the vacuum laminating method. As the insulator 210, a conventional resin having a high adhesiveness and a low dielectric constant can be used. Further, as will be described later, the insulator 210 may be first filled, then the opening may be processed by a laser or the like, and then the insulator 220 may be injected in a liquid state by using a dispenser or the like.

[Bottomed via structure]
FIG. 3 is a cross-sectional view showing another structural example of the wiring board 10 according to the first embodiment of the present technology.

In the above example, the example in which the insulators 210 and 220 are filled from both sides of the base material 100 has been described, but the insulators 210 and 220 may be filled from only one side of the base material 100. As such an example, assume a structure (bottom via structure) in which the conductor 120 is formed so as to close one opening of the through hole 110.

In this case, in the above-mentioned vacuum laminating method, a photosensitive sheet resist is attached to one side of the base material 100, and pressure is applied under vacuum.

In this example, an example in which a bottom (conductor 120) is formed in one opening of the through hole 110 has been described, but a hole is formed from one side of the base material 100 and a conductor 120 is formed in the bottom of the hole. You may.

[Constriction structure]
FIG. 4 is a cross-sectional view showing still another structural example of the wiring board 10 according to the first embodiment of the present technology.

In the above example, the shape of the through hole 110 is assumed to be a hole that vertically penetrates the base material 100. On the other hand, in this structural example, a constricted shape is provided in a part of the through hole 110. In this case, since the conductor 120 is formed along the side wall of the through hole 110, it also has a constricted shape.

This constricted structure has the effect of suppressing the influence of the expansion force of the insulators 210 and 220 filled in the through holes 110.

As described above, in the first embodiment of the present technology, the photosensitive sheet resist having the two-layer structure of the insulators 210 and 220 is bonded to the base material 100 and filled in the through holes 110 by the vacuum laminating method. As a result, the insulators 210 and 220 having different properties can be filled in the through hole 110 by a simple method.

<2. Second Embodiment>
[Structure of wiring board]
FIG. 5 is a diagram showing a structural example of the wiring board 10 according to the second embodiment of the present technology. In the figure, a is a cross-sectional view and b is a top view.

The wiring board 10 in the second embodiment uses a material having a low coefficient of linear expansion such as glass or silicon as the base material 100, and is formed in a through hole 110 penetrating from the front surface to the back surface of the base material 100 and its side wall. It is the same as the first embodiment described above in that it includes the conductor 120.

In this second embodiment, two types of insulators 230 and 240 are shown. As the particular type of insulator 230, one having higher adhesion than the other types of insulator 240 is adopted. As the other type of insulator 240, one having a lower expansion rate than that of a specific type of insulator 230 is adopted. That is, the relationship between the two is the same as that of the insulators 210 and 220 in the first embodiment described above.

The insulator 230 is granular insulating particles. The insulator 240 is a resin that fills the gaps in the insulator 230. However, the insulator 240 may be a void such as a vacuum layer.

In this second embodiment, it is assumed that the insulators 230 and 240 are filled in the through holes 110 by the squeegee method. Assuming an organic material as the insulator 230, a part of the insulator 230 is melted by applying heat after filling, and as shown in b in the figure, the contact portion 231 with the conductor 120 on the side wall of the through hole 110. Has a state of being deformed along the shape of the conductor 120. Similarly, the insulator 230 has a state of being deformed along each other's shape at a contact portion with another granular insulator 230.

[Manufacturing method of wiring board]
FIG. 6 is a process diagram showing an example of a manufacturing method of the wiring board 10 according to the second embodiment of the present technology.

As shown in a in the figure, the cover sheet 310 is attached to the back surface of the base material 100.

As shown in b in the figure, the insulators 230 and 240 are supplied to the inside of the conductor 120, pressure is applied by the squeegee 410, and the overflowing insulators 230 and 240 are removed (squeegee method). ).

As shown in c in the figure, the base material 100 is heated in the baking process, and then the cover sheet 310 is removed.

Specific examples of the insulator 230 include resin beads. Specific product names include Technopolymer ARX and AEX (Sekisui Plastics).

Further, as a resin having a linear expansion coefficient close to that of glass, for example, silica beads can be mentioned. Specific product names include silica spherical fine particles (Nippon Steel & Sumikin Materials Co., Ltd.). In the case of this product, there is a small diameter with an average particle size of 0.2 um, which is a sufficiently small size for TGV filling. In addition, the particles become amorphous, and the CTE is very small, about 0.5 ppm. In this case, since the CTE is smaller than about 3 ppm of the glass, it can be adjusted by, for example, setting the filling rate to about 50% and filling the empty wall with resin. The filling rate may be adjusted by mixing a large-diameter product and a small-diameter product of silica particles. Silica particles coated with a thin film of resin may be used to leave the gaps in space.

[Bottomed via structure]
FIG. 7 is a cross-sectional view showing another structural example of the wiring board 10 according to the second embodiment of the present technology.

Also in this second embodiment, a bottomed via structure can be assumed as in the first embodiment described above. In this case, in the above-mentioned squeegee method, the insulators 230 and 240 are supplied and pressure is applied from the opening of the through hole 110 that is not blocked by the conductor 120.

[Constriction structure]
FIG. 8 is a cross-sectional view showing still another structural example of the wiring board 10 according to the second embodiment of the present technology.

Also in this second embodiment, as in the case of the first embodiment described above, a constricted structure can be assumed as the shape of the through hole 110. With this constricted structure, the effect of suppressing the influence of the expansion force due to the insulators 230 and 240 filled in the through holes 110 can be obtained.

As described above, in the second embodiment of the present technology, the insulators 230 and 240 are filled in the through holes 110 by the squeegee method. Thereby, the insulators 230 and 240 having different properties can be filled in the through hole 110 by a simple method.

<3. Modification example>
In the above-described embodiment, the inside of the conductor 120 of the through hole 110 is filled with an insulator by using a photosensitive sheet resist or insulating particles. Here, as a modified example thereof, an example in which an insulator is filled, an opening is processed by a laser or the like, and another insulator is injected will be described.

[First modification]
FIG. 9 is a process diagram showing a first modification of the method for manufacturing the wiring board 10 according to the embodiment of the present technology.

In this example, as shown in a in the figure, the insulator 210 is filled inside the conductor 120 of the through hole 110. Then, as shown in b in the figure, the opening is processed by a laser or the like. Then, as shown in c in the figure, the insulator 220 is injected into the opening. Thereby, two kinds of insulators 210 and 220 can be filled inside the conductor 120 of the through hole 110.

[Second variant]
FIG. 10 is a process diagram showing a second modification of the method for manufacturing the wiring board 10 according to the embodiment of the present technology.

In this example, as in the first modification described above, as shown in a in the figure, the inside of the conductor 120 of the through hole 110 is filled with an insulator 210, and as shown in b in the figure, a laser is used. Perform opening processing by such means. Then, as shown in c in the figure, the openings are filled with insulators 230 and 240. The insulators 230 and 240 are the two types of insulators 230 and 240 in the second embodiment described above. Therefore, this allows three types of insulators 210, 230 and 240 to be filled inside the conductor 120 of the through hole 110.

It should be noted that the above-described embodiment shows an example for embodying the present technology, and the matters in the embodiment and the matters specifying the invention in the claims have a corresponding relationship with each other. Similarly, the matters specifying the invention within the scope of claims and the matters in the embodiment of the present technology having the same name have a corresponding relationship with each other. However, the present technology is not limited to the embodiment, and can be embodied by applying various modifications to the embodiment without departing from the gist thereof.

It should be noted that the effects described in the present specification are merely examples and are not limited, and other effects may be obtained.

The present technology can have the following configurations.
(1) Base material and
The holes that penetrate the base material and
A conductor formed along the side wall of the hole and
A wiring board including a plurality of types of insulators filled inside the conductor.
(2) Of the plurality of types of insulators, a specific type of insulator has higher adhesion than other types of insulators.
The wiring board according to (1), wherein the other type of insulator has a lower expansion rate than the specific type of insulator.
(3) The particular type of insulator covers the conductor.
The wiring board according to (2) above, wherein the other type of insulator is formed inside the conductor.
(4) The wiring board according to (3) above, wherein the particular type of insulator includes a portion inside the conductor that is connected to each other in the pore diameter direction.
(5) The wiring board according to (3) or (4) above, wherein the area ratio of the specific type of insulator to the other type of insulator in the pore diameter direction changes with respect to the penetration direction.
(6) The wiring board according to (3) above, wherein the other type of insulator includes a type of granular insulator different from the specific type of insulator.
(7) The specific type of insulator is a granular insulator.
The wiring board according to (2) above, wherein the other type of insulator is filled in the gaps between the granular insulators.
(8) The wiring board according to (7), wherein the granular insulator has a state of being deformed along the shape of the conductor at a contact portion with the conductor.
(9) The wiring board according to (7) or (8) above, wherein the granular insulator has a state of being deformed along the shape of each other at a contact portion with the other granular insulator.
(10) The wiring board according to any one of (1) to (9) above, further comprising another conductor that closes one opening of the through hole.
(11) The wiring board according to any one of (1) to (10) above, wherein the base material is silicon or glass.
(12) A step of attaching a sheet material made of a plurality of types of insulators to at least one surface of a base material having a through hole and a conductor formed along the side wall of the hole.
A method for manufacturing a wiring board, comprising a step of applying pressure under vacuum to fill the inside of the conductor with the sheet material.
(13) A step of supplying a plurality of types of insulators including a granular insulator from one surface of a base material including a through hole and a conductor formed along the side wall of the hole to the inside of the conductor.
A method for manufacturing a wiring board, comprising a step of applying pressure from one surface of the base material to the plurality of types of insulators inside the conductor.

10 Wiring board 100 Base material 110 Through hole 120 Conductor 210, 220, 230, 240 Insulator 231 Contact part 310 Cover sheet 410 Squeegee

Claims (13)

With the base material
The holes that penetrate the base material and
A conductor formed along the side wall of the hole and
A wiring board including a plurality of types of insulators filled inside the conductor. Of the plurality of types of insulators, a specific type of insulator has higher adhesion than other types of insulators.
The wiring board according to claim 1, wherein the other type of insulator has a lower expansion rate than the specific type of insulator. The particular type of insulator coats the conductor and
The wiring board according to claim 2, wherein the other type of insulator is formed inside the conductor. The wiring board according to claim 3, wherein the particular type of insulator includes a portion inside the conductor that is connected to each other in the pore diameter direction. The wiring board according to claim 3, wherein the area ratio of the specific type of insulator to the other type of insulator in the hole radial direction changes with respect to the penetration direction. The wiring board according to claim 3, wherein the other type of insulator includes a type of granular insulator different from the specific type of insulator. The particular type of insulator is a granular insulator.
The wiring board according to claim 2, wherein the other type of insulator is filled in the gaps between the granular insulators. The wiring board according to claim 7, wherein the granular insulator has a state of being deformed along the shape of the conductor at a contact portion with the conductor. The wiring board according to claim 7, wherein the granular insulator has a state of being deformed along the shape of each other at a contact portion with the other granular insulator. The wiring board according to claim 1, further comprising another conductor that closes one opening of the through hole. The wiring board according to claim 1, wherein the base material is silicon or glass. A step of attaching a sheet material made of a plurality of types of insulators to at least one surface of a base material having a hole to be penetrated and a conductor formed along the side wall of the hole.
A method for manufacturing a wiring board, comprising a step of applying pressure under vacuum to fill the inside of the conductor with the sheet material. A step of supplying a plurality of types of insulators including a granular insulator from one surface of a base material having a through hole and a conductor formed along a side wall of the hole to the inside of the conductor.
A method for manufacturing a wiring board, comprising a step of applying pressure from one surface of the base material to the plurality of types of insulators inside the conductor.

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