TW201713180A - Method for producing circuit board, circuit board, and apparatus for producing circuit board - Google Patents

Abstract

Disclosed is a method for producing a circuit board that enables the achievement of a finer wiring pattern while ensuring adhesion between a seed layer and an insulating layer. This method comprises, as steps for producing a circuit board: a first step for forming a through hole that runs through an insulating layer of a circuit board material in which the insulating layer is laminated upon a conductive layer; a second step for, after the first step, desmearing the circuit board material by irradiating the circuit board material with ultraviolet rays having a wavelength of 220 nm or less; a third step for, after the second step, forming a seed layer upon the inner surface of the through hole and upon the insulating layer by removing the oxide film at the bottom of the through hole and having material particles run into and adhere to the inner surface of the through hole and the insulating layer; and a fourth step for forming a plating layer upon the seed layer by electrolytic plating, said plating layer being formed from a conductive material.

Description

Method for manufacturing wiring board, wiring board, and wiring board manufacturing apparatus

The present invention relates to a method of manufacturing a wiring board formed by laminating an insulating layer and a conductive layer, a wiring board manufactured by the manufacturing method, and a wiring board manufacturing apparatus.

As a wiring board on which a semiconductor element such as a semiconductor integrated circuit element or the like is mounted, a multilayer wiring board formed by alternately laminating an insulating layer and a conductive layer (wiring layer) is known.

As an example of a manufacturing process of a multilayer wiring board, first, a portion of the insulating layer and the conductive layer is removed by applying drilling and laser processing to a wiring board material formed by laminating an insulating layer on the conductive layer. To form through holes and through holes. At this time, a slag (residue) due to a material constituting the insulating layer and the conductive layer is generated in the wiring board material. Therefore, the desmear treatment for removing the slag of the wiring substrate material is performed.

Next, a seed layer is formed on the insulating layer and the inner surface of the via hole or the like, and after forming a photoresist pattern on the insulating layer, the conductive material is laminated by electrolytic plating. Thereafter, the conductor circuit pattern is formed by removing the photoresist pattern and the seed layer. After that, semiconductor elements were produced through various processes.

Patent Document 1 discloses a substrate manufacturing method having a process of removing a slag generated in a through hole forming process by wet degreasing, and a process of forming a seed layer by electroless plating.

[Previous Technical Literature]

[Patent Literature]

[Patent Document 1] Japanese Patent Laid-Open Publication No. 2003-318519

In the technique described in the above Patent Document 1, the seed layer is formed by electroless plating after the dregs treatment, but it is necessary to set the surface of the insulating layer to be moderate in order to ensure the adhesion between the seed layer and the insulating layer. In a rough state, the seed layer is strongly fixed to the surface of the insulating layer by a fixing effect. In the technique described in the above Patent Document 1, the wet degreasing treatment is performed as a desmear treatment to roughen the surface of the insulating layer.

However, in recent years, semiconductor elements have been miniaturized, and wiring boards have been required to be miniaturized. However, as described above, in order to obtain a fixing effect and roughen the surface of the insulating layer, the wiring pattern formed thereon, in particular, the fine wiring pattern of L/S (line/space) = 10/10 μm or less becomes It is erected and the wiring board cannot be made fine.

Therefore, the problem of the present invention is to provide a wiring board which can realize the miniaturization of the wiring pattern while ensuring the adhesion between the seed layer and the insulating layer. Manufacturing method, wiring board, and wiring board manufacturing apparatus.

In order to solve the above problems, the first aspect of the method for manufacturing a wiring board according to the present invention includes forming a through hole penetrating the insulating layer with respect to a wiring board material in which an insulating layer is laminated on a conductive layer; In the second step, the wiring substrate material forming the through-hole is irradiated with ultraviolet rays having a wavelength of 220 nm or less to perform desmear treatment of the wiring substrate material, and the third process is performed by removing the pre-squeezing residue. An oxide film of a conductive material at the bottom of the through hole is treated to form a seed layer by causing material particles to collide with each other in the through hole and the insulating layer; and a fourth process is performed on the seed layer by electrolysis Electroplating forms a plating layer made of a conductive material.

Thus, the roughening of the surface of the insulating layer can be suppressed by performing the desmear treatment by ultraviolet rays. Therefore, the fine wiring pattern can be appropriately formed. Further, since the seed particles are formed by collision of the material particles, the adhesion strength to the insulating layer can be ensured by the seed layer without depending on the fixing effect as in the prior art. In particular, by irradiating ultraviolet rays having a wavelength of 220 nm or less which does not transmit the insulating layer, color centers (structural defects and bonding defects) can be generated on the surface of the insulating layer. At this time, the material particles (conductive material) are driven into the insulating layer, and energy is applied to the bonding defect portion existing on the surface of the resin subjected to ultraviolet irradiation, whereby a new chemical bonding action can be generated between the metal particles and the resin. Thereby, compared with the metal particles colliding with the resin that is not irradiated with ultraviolet rays having a wavelength of 220 nm or less, a strong bonding force can be formed. Seed layer.

Further, in the conductive material at the bottom of the through-hole after the desmear treatment, an oxide film is formed due to the passage of time after the treatment, and when the oxide film is formed to form a seed layer, the connectivity between the seed layer and the conductive layer is lowered. Then, there is a possibility that the connection strength between the conductive layer and the plating layer is lowered. Therefore, in the third process, the removal of the oxide film and the formation of the seed layer ensure the connectivity of the seed layer to the conductive layer.

In the above method for manufacturing a wiring board, in the third aspect, the oxide film may be removed by ion etching, and the oxide film may be removed by a chemical solution, and the chemical solution of hydrogen peroxide and sulfuric acid may be removed. The above oxide film may also be used. Thereby, a seed layer which ensures the strength of connection with the conductive layer can be formed.

Further, in the above method for manufacturing a wiring board, in the third aspect, the oxide film may be removed by ion etching, and the seed layer may be formed by a sputtering method. Thereby, the direction in which the voltage is applied can be reversed, and the removal of the oxide film can be switched to the formation of the seed layer.

Further, the wiring board of the present invention is produced by any of the above methods for manufacturing a wiring board. Therefore, the wiring board can be used as a fine wiring substrate which ensures high adhesion between the seed layer and the insulating layer and ensures high connection strength between the conductive layer and the plating layer.

In the same manner as the wiring board manufacturing apparatus of the present invention, the ultraviolet irradiation unit is provided with a wiring substrate material which is formed by laminating an insulating layer on the conductive layer and forming a through hole penetrating the insulating layer. The following ultraviolet rays are used to perform the wiring base sheet And a seed layer forming portion for removing an oxide film of a conductive material formed on a bottom portion of the through hole subjected to the desmear treatment, and using the material in the through hole and the insulating layer The particles collide and form a seed layer. Thereby, it is possible to manufacture a wiring board which ensures the adhesion between the seed layer and the insulating layer and ensures high connection strength between the conductive layer and the plating layer.

According to the present invention, the wiring pattern can be made fine while ensuring the adhesion between the seed layer and the insulating layer, and a highly reliable fine wiring substrate can be manufactured.

10‧‧‧Insulation

11‧‧‧ Conductive layer

12‧‧‧Insulation

12a‧‧‧through hole

13‧‧‧ seed layer

14‧‧‧Electroplating

100‧‧‧ samples

111‧‧‧ Conductive layer

112‧‧‧Insulation

112a‧‧‧through hole

114‧‧‧Electroplating

210‧‧‧Wiring substrate manufacturing equipment

211‧‧‧UV irradiation device

212‧‧‧Ultrasonic washing and drying equipment

213‧‧‧etching ‧sputtering device

220‧‧‧Wiring substrate manufacturing device

221‧‧‧UV irradiation device

222‧‧‧Ultrasonic washing and drying equipment

223‧‧‧mask peeling device

224‧‧‧etching ‧sputtering device

AI‧‧‧ argon ion

C‧‧‧色中心

L‧‧‧Laser

P‧‧‧Plastic

R‧‧‧resist pattern

S‧‧‧ slag

T‧‧‧ target material

TP‧‧‧ target particles (metal particles)

F‧‧‧Oxide film

Fig. 1 is a view showing a method of manufacturing a wiring board of the embodiment.

Fig. 2 is a graph showing the ultraviolet transmittance characteristics of an epoxy resin.

Fig. 3 is a view showing sputtering applied to a resin that receives ultraviolet light of 220 nm or less.

Fig. 4 is a view showing sputtering applied to a resin which is subjected to ultraviolet light of 250 nm.

[Fig. 5] A diagram in which sputtering is applied after ion etching is applied.

Fig. 6 is a view in which an oxide film is placed and sputtering is applied.

Fig. 7 is a view for explaining evaluation of through-hole connection strength.

FIG. 8 is a schematic view showing a structure of a wiring board manufacturing apparatus.

Hereinafter, embodiments of the present invention will be described based on the drawings.

Fig. 1 is a view showing a method of manufacturing a wiring board of the embodiment. In the present embodiment, the wiring board to be manufactured is a multilayer wiring board formed by laminating a conductive layer (wiring layer) and an insulating layer on a core substrate. The core substrate is made of, for example, glass epoxy resin or the like. As a material constituting the conductive layer (wiring layer), for example, copper, nickel, gold, or the like can be used.

The insulating layer is composed of, for example, a resin containing a particulate filler made of an inorganic substance. As such a resin, for example, an epoxy resin, a bismaleimide-triazabenzene resin, a polyimide resin, a polyester resin or the like can be used. Further, as the material constituting the granular filler, for example, cerium oxide, aluminum oxide, mica, ceric acid salt, barium sulfate, magnesium hydroxide, titanium oxide or the like can be used.

When manufacturing a multilayer wiring board, first, as shown in FIG. 1(a), a wiring board material formed by laminating the conductive layer 11 and the insulating layer 12 is formed. As a method of forming the insulating layer 12 on the conductive layer 11, a method of curing the insulating layer forming material after the insulating layer forming material containing the particulate filler in the liquid thermosetting resin is applied, And a method of bonding an insulating sheet containing a particulate filler by thermocompression bonding or the like.

Next, as shown in FIG. 1(b), the insulating layer 12 is processed by using the laser light L or the like to form a through hole 12a reaching the depth of the conductive layer 11. As a method of laser processing, a method using a CO ₂ laser, a method using a UV laser, or the like can be utilized. Further, the method of forming the through hole 12a is not limited to the laser processing, and for example, drilling processing or the like may be used.

When the through hole 12a is formed in this way, the inner wall surface (side wall) of the through hole 12a of the insulating layer 12, the peripheral region of the through hole 12a of the surface of the insulating layer 12, and the bottom portion of the through hole 12a, that is, the conductive layer 11 A slag (residue) S due to a material constituting the conductive layer 11 and the insulating layer 12 occurs in a portion where the through hole 12a is exposed.

Therefore, as shown in Fig. 1(c), the treatment for removing the slag S (with the desmear treatment) is performed. In the present embodiment, as the desmear treatment, a so-called optical desmear process in which the slag S is removed by irradiating ultraviolet rays (UV) to the portion to be processed is used. More specifically, in the optical desmear treatment, an ultraviolet irradiation treatment process for irradiating the processed portion of the wiring substrate material with the ultraviolet rays is performed, and after the ultraviolet irradiation treatment process, physical vibration is applied to the wiring substrate material. Physical vibration treatment engineering.

Here, the optical desmear treatment will be described in detail.

The ultraviolet irradiation treatment can be carried out, for example, in an atmosphere containing oxygen such as the atmosphere. As the ultraviolet light source, various types of lamps having an emission wavelength of 220 nm or less, preferably 190 nm or less of ultraviolet rays (vacuum ultraviolet rays) can be used. Here, the wavelength of 220 nm is that when the wavelength of the ultraviolet light exceeds 220 nm, it is difficult to decompose and remove the slag caused by the organic substance such as resin.

The slag resulting from the organic substance is decomposed by ultraviolet rays having a wavelength of 220 nm or less by irradiation with ultraviolet rays having a wavelength of 220 nm or less and ozone and active oxygen generated by irradiation with ultraviolet rays. Further, the slag which is caused by the inorganic substance, specifically, cerium oxide and aluminum oxide are weak due to irradiation with ultraviolet rays.

As the ultraviolet light source, for example, a xenon excimer lamp (spike wavelength: 172 nm) in which helium gas is enclosed, a low pressure mercury lamp (185 nm glow line), or the like can be used. Among them, as a person who performs the desmear treatment, for example, a bismuth excimer lamp is preferable.

In the ultraviolet irradiation device that performs the above-described ultraviolet irradiation treatment, the wiring substrate material to be processed, which is exposed to ultraviolet rays in an atmosphere containing a processing gas for oxygen, is heated to, for example, 120° C. or higher and 190° C. or lower (for example, 150 ° C). Moreover, the distance between the ultraviolet light emission window and the wiring substrate material to be processed is set to, for example, 0.3 mm. In addition, the illuminance of the ultraviolet ray, the irradiation time of the ultraviolet ray, and the like can be appropriately set in consideration of the residual state of the slag S or the like.

Further, the physical vibration processing can be performed, for example, by ultrasonic vibration processing. The frequency of the ultrasonic wave subjected to the ultrasonic vibration processing is preferably 20 kHz or more and 70 kHz or less. When the frequency of the ultrasonic wave exceeds 70 kHz, the slag due to the inorganic substance is destroyed and it is difficult to separate it from the wiring board material.

In such ultrasonic vibration processing, a liquid such as water or a gas such as air can be used as the vibration medium of the ultrasonic wave.

Specifically, when water is used as the vibration medium, the wiring substrate material can be immersed in water, for example, and the water ultrasonic wave can be vibrated in this state to perform ultrasonic vibration processing. When a liquid is used as the ultrasonic vibration medium, the processing time of the ultrasonic vibration processing is, for example, 10 seconds to 600 seconds.

Moreover, when air is used as a vibration medium, one can be used Ultrasonic vibration treatment is performed by blowing the compressed air ultrasonic vibration to the wiring substrate material. Here, the pressure of the compressed air is preferably 0.2 MPa or more. Further, the processing time of the ultrasonic vibration treatment by the compressed air is, for example, 5 seconds to 60 seconds.

The ultraviolet irradiation treatment engineering and the physical vibration treatment engineering described above may be performed once in this order, but it is preferable to repeat the ultraviolet irradiation treatment engineering and the physical vibration treatment engineering. Here, the number of repetitions of the ultraviolet irradiation treatment process and the physical vibration treatment process is appropriately set in consideration of the irradiation time of the ultraviolet rays of each ultraviolet irradiation treatment process, for example, once to five times.

In the ultraviolet irradiation treatment, ultraviolet rays having a wavelength of 220 nm or less are irradiated to a processing gas containing oxygen to generate ozone and active oxygen, and the slag S due to the organic substance is decomposed by ozone and active oxygen and gas. Chemical. As a result, most of the slag S resulting from the organic matter is removed. At this time, the slag S due to the inorganic substance is exposed by the removal of the slag S caused by the organic substance, and further becomes weak due to the irradiation of the ultraviolet ray.

Then, by applying a physical vibration treatment in this state, the residue of the slag S caused by the inorganic substance and the slag S caused by the organic substance is exposed and destroyed by the mechanical action by vibration. Or, because of the shrinkage of the slag S due to the inorganic substance and the difference in thermal expansion which occurs when the slag S is irradiated with ultraviolet rays, a slight gap is generated between the slags, which is caused by the slag S of the inorganic substance. It is detached from the wiring substrate material by applying physical vibration treatment. Result from the wiring base The plate material completely removes the slag S resulting from the inorganic substance and the slag S resulting from the organic substance.

According to the optical desmear treatment of the present embodiment, it is not necessary to use a chemical treatment that requires waste liquid treatment as long as the wiring substrate material is subjected to ultraviolet irradiation treatment or physical vibration treatment.

When the optical desmear treatment is completed, next, a seed layer formation treatment for forming a seed layer is performed. In the seed layer forming process, as shown in FIG. 1(d), the removal process of the oxide film F formed on the bottom of the via hole 12a is removed, as shown in FIG. 1(e), on the upper surface of the insulating layer 12 and The inner surface of the through hole 12a forms a forming process of the seed layer 13.

In the present embodiment, ion etching is used as a method of removing the oxide film F for the removal process. Specifically, as shown in FIG. 1(d), the target material T is placed against the wiring substrate material in an argon atmosphere, and the target material T is applied to the positive potential between the wiring substrate material and the target material T. The wiring board material relatively has a voltage of a negative potential. Thereby, a plasma P of argon is generated between the wiring substrate material and the target material T, and the argon ions AI in the plasma P fly toward the wiring substrate material which is relatively negatively charged, and collide with the oxide film F or the like. By this conflict, the oxide film F is removed by etching.

In the present embodiment, sputtering is used as a method of forming the seed layer 13 in the forming process. Specifically, as shown in FIG. 1(e), a voltage having a voltage polarity opposite to the polarity of the voltage of the removal process is applied between the wiring substrate material and the target material T. Thereby, between the wiring substrate material and the target material T, a plasma P of argon is generated, and an argon ion AI in the plasma P is generated. It collides with the target material T which becomes a negative potential relatively. Because of the collision, the target particles TP are ejected from the target material T, and the target particles TP collide with the surface of the wiring substrate material. The seed layer 13 is formed by adhering the target particles TP in this manner. In the sputtering of the seed layer 13, for example, in order to secure the adhesion strength, Ti (titanium) is first used as the target material T to form a layer to be a base (about 10 nm to 100 nm), and then as a target material T. A Cu (copper) is used to form a seed layer (about 100 nm to 1000 nm).

Next, as shown in FIG. 1(f), a photoresist pattern R is formed on the seed layer 13. As a method of forming the photoresist pattern R, for example, a method of forming a pattern by exposure ‧ development after application of a photoresist on the seed layer 13 can be used. Next, as shown in FIG. 1(g), the seed layer 13 is formed by electroplating using a plating power supply path to cover the opening portion of the photoresist pattern R from the via hole 12a. As the plating layer 14, for example, a layer made of Cu (copper) or the like (about 20 μm to 50 μm) can be used.

Thereafter, as shown in FIG. 1(h), the photoresist pattern R is removed, and then, as shown in FIG. 1(i), the plating layer 14 is masked, and the seed layer 13 is removed (flash-etched).

In addition, in each of the projects shown in FIG. 1, the first project shown in FIG. 1(b) corresponds to the formation of a through hole in the insulating layer laminated on the conductive layer, and the project shown in FIG. 1(c) corresponds to After the first process, ultraviolet rays having a wavelength of 220 nm or less were irradiated to perform a second process of desmear treatment. Further, in the works shown in FIG. 1(d) and FIG. 1(e), the third project of forming a seed layer in the through hole and the insulating layer after the second process is shown in FIG. 1(g). Corresponding to the seed layer by electrolytic plating to form a conductive material The fourth project of the electroplated layer.

As described above, in the present embodiment, after the slag S is removed by the optical desmear treatment, the seed layer 13 is formed by sputtering.

Previously, the adhesion between the insulating layer and the seed layer was ensured by the anchoring effect. That is, in order to ensure the adhesion between the insulating layer and the seed layer, it is preferable to roughen the surface of the insulating layer. However, when the surface of the insulating layer is roughened, in particular, the fine wiring pattern of L/S (line/spacer) = 10/10 μm or less is not erected, so that it is difficult to fabricate a fine wiring board. Therefore, in order to manufacture a fine wiring substrate, it is necessary to prevent the surface of the insulating layer from being roughened, and to ensure the adhesion between the insulating layer and the seed layer. The present inventors have found that the desmear treatment and the seed layer formation treatment, which is a part of the manufacturing process of the wiring substrate, can be performed by a combination of an optical desmear treatment and a sputtering method, and the surface of the insulating layer can be prevented from being roughened. Ensure the adhesion between the insulation layer and the seed layer.

Optical desmear treatment can prevent the surface of the object to be roughened to remove the glue. Further, in the optical desmear treatment of the present embodiment, since the physical vibration treatment is performed after the ultraviolet irradiation treatment, the slag caused by the organic substance and the slag resulting from the inorganic substance can be appropriately removed.

Further, since the seed layer 13 is formed by sputtering, the seed layer 13 can be formed with sufficient adhesion strength on the insulating layer 12 whose surface is not roughened. In particular, ultraviolet rays having a wavelength of 220 nm or less are used for the ultraviolet irradiation treatment, and after the ultraviolet irradiation treatment, the seed layer formation treatment using the sputtering method is performed, so that a fine and strong species can be formed on the insulating layer 12. Sublayer 13. Hereinafter, this point will be described in detail.

Fig. 2 is a view showing the ultraviolet transmittance characteristics of an epoxy resin (25 μm film). In FIG. 2, the horizontal axis represents the wavelength (nm) of ultraviolet rays, and the vertical axis represents the transmittance (%) of ultraviolet rays.

As shown in FIG. 2, in a region having a wavelength of 220 nm or more, light may be transmitted through the resin in a region where light is incident on one of the near ultraviolet rays, and the transmittance becomes smaller as the wavelength becomes shorter. Specifically, in a region exceeding a wavelength of 300 nm, light is almost transmitted through the resin. Although the ultraviolet ray is slightly absorbed by the resin at a wavelength of 300 nm or less, the absorption is not high, and the degree of ultraviolet ray is not completely blocked. This is because the entire surface of the resin absorbs ultraviolet rays, and the resin excited by the ultraviolet rays is widely distributed throughout the resin.

On the other hand, ultraviolet rays having a wavelength of 220 nm or less do not transmit the resin. This extinction is high, and ultraviolet rays are absorbed in the surface layer of the resin. At a shorter wavelength, the ultraviolet rays are completely absorbed in the surface of the resin, and the excitation portions generated by the absorption of the ultraviolet rays are layered on the surface of the resin.

Then, the active resin portion is newly bonded by the energy when the target particles flying by sputtering are driven into the resin, and the target particles are strongly fixed.

Fig. 3 is a view showing a state in which sputtering is applied to a resin that receives ultraviolet rays having a wavelength of 220 nm or less, and Fig. 4 is a view showing a state in which sputtering is applied to a resin that receives ultraviolet rays having a wavelength of 250 nm or less. In FIG. 3 and FIG. 4, it is disclosed that the insulating layer 10 is included and has a layer 10 on the insulating layer 10 . The conductive layer 11 of the desired pattern on the surface, and a portion of the wiring substrate material formed by the insulating layer 12 laminated on the insulating layer 10 including the conductive layer 11.

As an optical desmear treatment for removing the dross (not shown) remaining in the through hole 12a, as shown in FIG. 3(a), when ultraviolet rays (UV) having a wavelength of 220 nm or less are irradiated, as described above, the ultraviolet rays are insulated. The surface of the layer 12 is absorbed, and a color center (bonding defect, structural defect) C is generated on the surface of the insulating layer 12. The color center C is excited by absorbing the ultraviolet rays described above, and is caused by a chemical bond breakage of atoms or a change in a bonding state.

With respect to the surface of the insulating layer 12 in which the color center C is thus generated, as shown in FIG. 3(b), when the target particle (metal particle) TP flying from the sputtering source is driven, the color center C strongly captures the metal particle. TP. That is, by applying energy to the bonding defect portion existing on the surface of the resin subjected to ultraviolet irradiation, a new chemical bonding action can be generated between the metal particles and the resin. Fig. 3(c) is an enlarged view of the surface of the insulating layer 12 at this time. Thus, the adhesion between the insulating layer 12 that receives ultraviolet rays having a wavelength of 220 nm or less and the metal film to be sputtered (the seed layer 13 of FIG. 1) is extremely strong.

On the other hand, the wiring board material similar to the wiring board material shown in FIG. 3 is subjected to optical desmear treatment, and when irradiated with ultraviolet rays having a wavelength of, for example, 250 nm, the distribution of the excited resin in the insulating layer 12 subjected to ultraviolet rays is applied. It is loose and distributed throughout the insulating layer 12. That is, as shown in FIG. 4(a), the color centers C are not distributed on the surface of the insulating layer 12, and are distributed inside the insulating layer 12.

Therefore, for the surface of the insulating layer 12, as shown in FIG. 4(b), even The target particles (metal particles) TP flying from the sputtering source are driven, and the trapping action of the metal particles TP is also small. That is, in FIG. 4(c), as shown in an enlarged view of the surface of the insulating layer 12 at this time, there is no special bonding effect of the surface of the insulating layer 12 and the metal particles TP, and the metal film formed on the insulating layer 12 (FIG. 1) The adhesion of the seed layer 13) is not enhanced.

In the present embodiment, ultraviolet rays having a wavelength of 220 nm or less are used in the ultraviolet irradiation treatment, and a seed layer forming treatment using a sputtering method is performed after the ultraviolet irradiation treatment, whereby a fine and strong seed layer 13 can be formed on the insulating layer 12. . Therefore, the plating layer 14 to which electrolytic plating is applied to the substrate by the seed layer 13 indicates high adhesion to the insulating layer 12. Thus, the surface of the insulating layer 12 can be prevented from being roughened, and the adhesion between the insulating layer 12 and the seed layer 13 can be ensured. As a result, a highly reliable fine wiring substrate can be realized.

Further, the surface of the insulating layer 12 can be kept smooth, and the high frequency response can be improved. When the frequency becomes high, the signal has a property of focusing on the surface of the conductor by the skin effect. As described above, in order to obtain the fixing effect, if the surface of the insulating layer 12 is roughened, the signal transmission distance becomes long, and as a result, the transmission loss becomes large and the responsiveness deteriorates. In the present embodiment, the transmission loss can be reduced and the responsiveness can be improved.

As described above, in the present embodiment, the adhesion between the insulating layer 12 and the seed layer 13 can be ensured, but when the optical desmear treatment is excessively performed for some reason, and after the optical desmear treatment, the seed layer is formed before When placed for a long time, etc., the conductive layer 11 exposed at the bottom of the through hole 12a may cause an oxide film. Then, when the oxide film is placed to form the seed layer 13, the guide The connection strength between the electric layer 11 and the seed layer 13 is lowered. Therefore, in the present embodiment, ion implantation is performed by preparation as the seed layer 13, and the seed layer 13 strongly connected to the conductive layer 11 can be formed. Hereinafter, this point will be further described.

Fig. 5 is a view showing a state in which sputtering is applied after ion etching is applied, and Fig. 6 is a view showing a state in which an oxide film is placed and sputtering is applied. Even in FIGS. 5 and 6, a conductive layer 11 including an insulating layer 10 having a desired pattern laminated on the surface of the insulating layer 10, and laminated on the insulating layer 10 including the conductive layer 11 are disclosed. One part of the wiring substrate material composed of the insulating layer 12.

When the wiring substrate material forming the via hole 12a is ion-etched, the wiring substrate material side becomes a cathode, and as shown in FIG. 5(a), the ion AI collides with the oxide film F on the conductive layer 11, and the oxide film F is removed by etching.

With respect to the surface of the conductive layer 11 from which the oxide film F is removed, before the oxide film F is formed again, as shown in FIG. 5(b), if the target particles (metal particles) TP flying from the sputtering source are driven, the metal particles are The TP is strongly adhered to the surface of the conductive layer 11 to be integrated. Fig. 5(c) is an enlarged view of the surface of the conductive layer 11 at this time.

On the other hand, as for the wiring board material similar to the wiring board material shown in FIG. 3, as shown in FIG. 6(a), when the oxide film F is placed and sputtering is applied, as shown in FIG. 6(b), the metal particles are used. TP adheres to the oxide film F. As shown in the enlarged view of the surface of the conductive layer 11 at this time as shown in FIG. 6(c), the layer structure of the stacked conductive layer 11 and the oxide film F and the seed layer 13 can be obtained, but since the oxide film F enters between them, the layer Low strength of construction, conductive layer The strength of the connection with the seed layer 13 is also low.

In the present embodiment, in the formation process of the seed layer, the seed layer 13 which is strongly integrated with the conductive layer 11 can be surely formed by performing the formation process after the removal process. Therefore, the plating layer 14 to which electrolytic plating is applied to the substrate by the seed layer 13 indicates the high connection strength with respect to the conductive layer 11.

(Example)

Next, an embodiment for confirming the effects of the present invention will be described.

<Wiring substrate material>

First, a core material made of a glass epoxy resin and a prepreg made of copper, a 25 μm epoxy resin laminated on both sides, and a laminate formed by high pressure pressurization and drying (epoxy substrate) ). A protective film made of a PET film having a thickness of 38 μm was attached to the laminate, and then laser processing was applied by a through hole processing machine (UV laser) to form a blind via hole at a pitch of 500 μm. The through hole opening diameter was set to Φ50 μm. In this way, the wiring substrate material is obtained. Moreover, at this time, it was confirmed that the slag remained in the bottom of the blind via hole of the wiring board material.

<Reference Example 1>

For the above-mentioned wiring substrate material, wet-type desmear treatment using permanganic acid solution is applied, and after peeling off the protective film, electroless copper plating (Electroless) Copper plating) forms a seed layer of 1 μm. Further, a Cu layer (electroplated layer) of 30 μm was formed on the substrate by electrolytic plating.

<Reference Example 2>

After the wet desmear treatment using the permanganic acid solution is applied to the wiring board material, the oxide film removal is performed by wet etching using a solution of mixed hydrogen peroxide and sulfuric acid. Then, after peeling off the protective film, a 1 μm seed layer was formed by electroless copper plating. Further, a Cu layer (electroplated layer) of 30 μm was formed on the substrate by electrolytic plating.

<Reference Example 3>

After the wet desmear treatment using the permanganic acid solution was applied to the wiring board material, ion etching was applied for 10 minutes to remove the oxide film. Then, after the protective film was peeled off, a seed layer of 0.33 μm (Ti/Cu = 0.03 μm / 0.3 μm) was formed by sputtering. Further, a Cu layer (electroplated layer) of 30 μm was formed on the substrate by electrolytic plating.

<Comparative Example 1>

To the wiring board material, an optical desmear treatment using ultraviolet rays having a wavelength of 172 nm was applied, and after peeling off the protective film, a seed layer of 0.33 μm (Ti/Cu=0.03 μm/0.3 μm) was formed by sputtering. Further, a Cu layer (electroplated layer) of 30 μm was formed on the substrate by electrolytic plating. Further, in the optical desmear treatment, ultraviolet irradiation treatment and physical vibration treatment (ultrasonic vibration treatment) are performed.

<Example 1>

After the optical desmear treatment using ultraviolet rays having a wavelength of 172 nm was applied to the wiring substrate material, the oxide film removal was performed by wet etching (treatment time: 5 minutes) using a solution of mixed hydrogen peroxide and sulfuric acid. Then, after the protective film was peeled off, a seed layer of 0.33 μm (Ti/Cu = 0.03 μm / 0.3 μm) was formed by sputtering. Further, a Cu layer (electroplated layer) of 30 μm was formed on the substrate by electrolytic plating. Further, in all of the following examples, in the optical desmear treatment, ultraviolet irradiation treatment and physical vibration treatment (ultrasonic vibration treatment) were carried out.

<Example 2>

After the optical desmear treatment using ultraviolet rays having a wavelength of 172 nm was applied to the wiring substrate material, ion etching was applied for 0.25 minutes to perform oxide film removal. Then, after the protective film was peeled off, a seed layer of 0.33 μm (Ti/Cu = 0.03 μm / 0.3 μm) was formed by sputtering. Further, a Cu layer (electroplated layer) of 30 μm was formed on the substrate by electrolytic plating.

<Example 3>

After the optical desmear treatment using ultraviolet rays having a wavelength of 172 nm was applied to the wiring substrate material, ion etching was applied for 0.5 minutes to remove the oxide film. Then, after the protective film was peeled off, a seed layer of 0.33 μm (Ti/Cu = 0.03 μm / 0.3 μm) was formed by sputtering. Further, a Cu layer (electroplated layer) of 30 μm was formed on the substrate by electrolytic plating.

<Example 4>

After the optical desmear treatment using ultraviolet rays having a wavelength of 172 nm was applied to the wiring board material, ion etching was applied for 1 minute to remove the oxide film. Then, after the protective film was peeled off, a seed layer of 0.33 μm (Ti/Cu = 0.03 μm / 0.3 μm) was formed by sputtering. Further, a Cu layer (electroplated layer) of 30 μm was formed on the substrate by electrolytic plating.

<Example 5>

After the optical desmear treatment using ultraviolet rays having a wavelength of 172 nm was applied to the wiring substrate material, ion etching was applied for 5 minutes to remove the oxide film. Then, after the protective film was peeled off, a seed layer of 0.33 μm (Ti/Cu = 0.03 μm / 0.3 μm) was formed by sputtering. Further, a Cu layer (electroplated layer) of 30 μm was formed on the substrate by electrolytic plating.

<Example 6>

After the optical desmear treatment using ultraviolet rays having a wavelength of 172 nm was applied to the wiring board material, ion etching was applied for 10 minutes to remove the oxide film. Then, after the protective film was peeled off, a seed layer of 0.33 μm (Ti/Cu = 0.03 μm / 0.3 μm) was formed by sputtering. Further, a Cu layer (electroplated layer) of 30 μm was formed on the substrate by electrolytic plating.

<Example 7>

For the aforementioned wiring substrate material, after applying an optical desmear treatment using ultraviolet rays having a wavelength of 172 nm, ion etching is applied for 20 minutes, The oxide film is removed. Then, after the protective film was peeled off, a seed layer of 0.33 μm (Ti/Cu = 0.03 μm / 0.3 μm) was formed by sputtering. Further, a Cu layer (electroplated layer) of 30 μm was formed on the substrate by electrolytic plating.

With respect to the above-mentioned Reference Examples 1 to 3, Comparative Example 1, and Examples 1 to 6, the Cu layer of the substrate was cut by a cutting blade at a width of 1 cm in accordance with the method described in JIS H8630, Attachment 1, and pulled. The tester was subjected to a tear peel test in a 90 degree direction. Then, the via connection strength (%) and the repeatability (%) described later are obtained. The results are disclosed in Table 1.

The above-mentioned through-hole connection strength is subjected to a peeling test for 100 through holes on a substrate fabricated under the same conditions, and observed by a microscope. The way the through hole looks, calculates and represents the yield.

Fig. 7 is a view showing various states produced by the through holes in the peeling test.

For example, as shown in Fig. 7 (a), in the peeling test, when the plating layer 114 is peeled off from both the bottom and the side wall of the through hole 112a of the insulating layer 112 of the sample 100, it is judged to be defective (through hole bottom). Bad + bad sidewalls). The form shown in Fig. 7(a) occurs when the adhesion between the via hole bottom (the conductive layer 111 and the plating layer 114) and the sidewall of the via hole (the insulating layer 112 and the plating layer 114) is low.

On the other hand, as shown in FIG. 7( b ), when the plating layer 114 was peeled off together with the conductive layer 111 in the peeling test, it was judged to be good.

Further, as shown in FIG. 7(c), in the peeling test, the plating layer 114 was peeled off from the surface of the insulating layer 112, and when it was in a state of being in close contact with the through hole 112a, it was judged to be good. The form shown in Fig. 7(c) occurs when the adhesion in the through hole (the bottom of the through hole and the side wall) is very high.

Further, as shown in FIG. 7(d), in the peeling test, when the through hole 112a is largely collapsed, the aggregation failure occurs in the insulating layer 112, and it is judged to be good.

The above-mentioned repeat reliability is a test for setting the connection strength of the through holes for 100 through holes for each of the five substrates which are set under the same conditions after the setting of the dregs, and calculates and shows that 100% is obtained. The ratio of the strength of the through hole connection.

As shown in Table 1, in Reference Example 1, although the through-hole connection strength was 100%, although the good product was obtained, the repeat reliability was 40%, and three of the five sheets were obtained. Unable to get 100% good. Since the removal of the oxide film is not performed, the adhesion between the seed layer and the conductive layer is hindered by the oxide film in a part of the via holes.

In Reference Examples 2 to 3, the through-hole connection strength was 100%, and the repeatability was 80%. However, in the samples of Reference Examples 2 to 3, the wet type desmear-treated chemical solution has a function of roughening the surface of the epoxy resin, and the surface roughness in the side wall becomes large. Therefore, even if the through-hole connection strength is high, the peel strength is low, and the reliability of the substrate is low.

Further, in Comparative Example 1, although the through-hole connection strength was 100%, the good reliability was 40%, and the three sheets of the five sheets could not obtain 100% of the good products. Since the removal of the oxide film is not performed, the adhesion between the seed layer and the conductive layer is hindered by the oxide film in a part of the via holes.

On the other hand, in Example 1, the through-hole connection strength was 100%, and the repeatability was also 100%. This is because the oxide film is removed by wet etching, and the seed layer is in close contact with the conductive layer. Moreover, the roughening of the side walls is also suppressed by the optical desmear treatment.

In Examples 2 and 3, the through-hole connection strength was 100%, and the repeatability was 90 to 95%. This is because the oxide layer is removed by ion etching, and the seed layer is in close contact with the conductive layer. Moreover, the roughening of the side walls is also suppressed by the optical desmear treatment.

Further, in Examples 4 to 7, the through-hole connection strength was 100%, and the repeatability was also 100%. This is because the oxide film is completely removed by ion etching covering more than 1 minute. Moreover, the roughening of the side walls is also suppressed by the optical desmear treatment.

As described above, by using ultraviolet light having a wavelength of 220 nm or less The combination of the optical desmear treatment of the wire, the removal treatment of the oxide film, and the formation of the seed layer by sputtering can ensure high adhesion in the through hole and realize a highly reliable substrate. Further, since the surface of the resin can be kept smooth, the photoresist pattern for forming the fine wiring can be stably formed, and the fine wiring substrate can be produced with high precision.

(Wiring substrate manufacturing device)

The manufacture of the wiring board described above can be realized by the wiring board manufacturing apparatus shown below.

Fig. 8 is a schematic view showing the structure of a wiring board manufacturing apparatus. Here, FIG. 8( a ) discloses a structure of a wiring board manufacturing apparatus 210 for manufacturing a wiring board without using the above protective film, and FIG. 8( b ) discloses a wiring board manufacturing apparatus for manufacturing a wiring board using the above protective film. The construction of 220.

The wiring board manufacturing apparatus 210 shown in Fig. 8(a) includes an ultraviolet irradiation device 211, an ultrasonic cleaning/drying device 212, and an etching/sputtering device 213. The ultraviolet irradiation device 211 is an ultraviolet irradiation treatment for performing optical desmear treatment on a workpiece (wiring substrate material). The ultrasonic cleaning and drying device 212 is a physical vibration treatment for optical desmear treatment, and after performing ultrasonic vibration treatment (ultrasonic cleaning treatment), drying of the dried workpiece is performed. The etching/sputtering apparatus 213 performs a process of removing an oxide film from the surface of the workpiece after the optical desmear treatment and forming a seed layer by an ion etching method and a sputtering method.

The wiring board manufacturing apparatus 220 shown in FIG. 8(b) includes an ultraviolet irradiation device 221, an ultrasonic cleaning device 222, and a mask. Stripping device 223, etching ‧ sputtering device 224. The ultraviolet irradiation device 221 and the ultrasonic cleaning and drying device 222 are the same as the ultraviolet irradiation device 211 and the ultrasonic cleaning and drying device 212. The mask peeling device 223 performs a process of removing the protective film from the workpiece after the optical desmear treatment. The etching/sputtering device 224 performs a process of further removing an oxide film from the surface of the workpiece after removing the protective film and forming a seed layer by ion etching and sputtering.

According to the wiring board manufacturing apparatuses 210 and 220, it is possible to manufacture a wiring board which ensures the adhesion between the seed layer and the insulating layer and ensures high connection strength between the seed layer and the conductor layer.

Further, in Fig. 8, the ultraviolet irradiation devices 211 and 221 correspond to the ultraviolet irradiation portion, the ultrasonic cleaning devices 212 and 222 correspond to the vibration applying portion, and the etching/sputtering devices 213 and 224 correspond to the seed layer forming portion.

(Modification)

In the above embodiment, the state in which the seed layer is formed by the sputtering method has been described, but the present invention is not limited thereto. For example, a seed layer may be formed by an ion coating method. At this time, the same effect as when the seed layer is formed by sputtering can be obtained. In other words, as in the sputtering method and the ion coating method, the same effect as in the above embodiment can be obtained as long as the seed particles are formed by colliding with the material particles (metal particles).

Further, in the above-described embodiment, the state in which the oxide film is removed by the ion etching method has been described, but the present invention is not limited thereto. For example, the substrate material may be immersed in a chemical solution to remove the oxide film. As a liquid medicine, for example, mixed A chemical solution containing hydrogen peroxide and sulfuric acid is preferred, and it may be used as an aqueous sodium hydroxide solution. In the case where the chemical solution is used to remove the oxide film, the same effect as when the oxide film is removed by the ion etching method can be obtained.

11‧‧‧ Conductive layer

12‧‧‧Insulation

12a‧‧‧through hole

13‧‧‧ seed layer

14‧‧‧Electroplating

AI‧‧‧ argon ion

L‧‧‧Laser

P‧‧‧Plastic

R‧‧‧resist pattern

S‧‧‧ slag

T‧‧‧ target material

TP‧‧‧ target particles (metal particles)

F‧‧‧Oxide film

Claims (7)

A method of manufacturing a wiring board, comprising: a first step of forming a through hole penetrating through the insulating layer with respect to a wiring substrate material in which an insulating layer is laminated on a conductive layer; and a second process by forming The wiring substrate material of the through hole is irradiated with ultraviolet rays having a wavelength of 220 nm or less to perform desmear treatment of the wiring substrate material, and the third process is for removing a conductive material formed at the bottom of the through hole subjected to the desmear treatment. The oxide film forms a seed layer by adhering the material particles in the through hole and the insulating layer, and the fourth layer is formed on the seed layer to form a plating material made of a conductive material by electrolytic plating. Floor. The method for producing a wiring board according to the first aspect of the invention, wherein in the third aspect, the oxide film is removed by ion etching. The method for producing a wiring board according to the first or second aspect of the invention, wherein in the third aspect, the oxide film is removed by ion etching, and the seed layer is formed by a sputtering method. The method for producing a wiring board according to the first aspect of the invention, wherein the third step is to remove the oxide film by a chemical solution. The method of manufacturing a wiring board according to the fourth aspect of the invention, wherein In the third process described above, the oxide film is removed by mixing a chemical solution of hydrogen peroxide and sulfuric acid. A wiring board manufactured by the method for manufacturing a wiring board according to any one of the first to fifth aspects of the invention. An apparatus for manufacturing a wiring board, comprising: an ultraviolet ray irradiation unit that irradiates an ultraviolet ray having a wavelength of 220 nm or less with a wiring substrate material that is formed by laminating an insulating layer on a conductive layer and forming a through hole penetrating the insulating layer; a desmear treatment of the wiring board material; and a seed layer forming portion that removes an oxide film of a conductive material formed on the bottom of the through hole subjected to the desmear treatment, and uses the inside of the through hole and the insulating layer The material particles collide and form a seed layer.