JPH10154871A - Production of circuit board having bump contact and jet stream plating system employing the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To suppress bubbles from being entrained into a plating liquid by exposing a cathode, i.e., a conductive circuit, above the interface of the plating liquid, performing electroplating by jetting the plating liquid through a jet port toward the cathode thereby forming bump contacts on the surface of the cathode. SOLUTION: The jet stream plating system comprises a conductive circuit 4 provided on an insulating board 3 and serving as a cathode, a tank 1 for storing a plating liquid 8, a jet port 2 located below the interface of the plating liquid, and an anode 12 located in the plating liquid. The cathode, i.e., the conductive circuit 4, is exposed oppositely to the jet port 2 above the interface of the plating liquid using the jet stream plating system and then electrolytic plating is performed by jetting the plating liquid through the jet port 2 toward the cathode thus forming bump contacts 6 on the surface of the cathode of a circuit board.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for manufacturing a circuit board having bump contacts and a jet plating apparatus used therefor.

[0002]

2. Description of the Related Art In recent years, electronic devices have been reduced in size and speed,
In order to meet the demand for higher functionality, bonding in the size of an IC chip is also being performed in semiconductor mounting such as CSP. Further, inspection of various electrical characteristics such as a burn-in test is required to be performed at a die level.
A flexible film carrier has been developed for bonding to an IC chip having a fine pitch as described above and a contact for inspection. This has a so-called bump contact on the surface of the insulating substrate, which is in contact with a portion to be contacted of the device under test and the device to be mounted (see Japanese Patent Application Laid-Open No. 62-182672).

[0003] In forming bump contacts, electrolytic plating by a dipping method or a jet method is generally used. Technically, studies for eliminating abnormal deposition of bump contacts and for uniformly forming the height of bump contacts have been mainly conducted on semiconductor wafers. For example, JP-A-2-61089
In the publication, in order to eliminate the irregular bump contact due to the directionality of the flow of the plating solution on the surface to be plated, the nozzle for discharging the solution and the surface to be plated are kept in parallel, and the nozzle is two-dimensionally swung. In addition, a method using a jet cup (Japanese Unexamined Patent Publication No.
In Japanese Patent Publication No. 315434, a bump contact having a uniform height is obtained by holding a wafer by a regulating member and plating the wafer in a state of being floated in a horizontal position by an overflowing plating solution.

[0004]

However, it has been studied to make the bump contact height uniform by using a plating solution that does not contain a brightener, such as a noble metal plating such as gold or silver or a solder plating such as tin or lead. In many cases, bump contacts are formed using a bright plating solution containing a leveler and a brightener in a jet plating apparatus, and there are few studies on abnormal bump contacts such as deformation and omission.

For example, as disclosed in Japanese Patent Application Laid-Open No. 7-11498, in order to prevent decomposition of a brightener from occurring at an insoluble anode, the area of the insoluble anode should be 0.5 times or more and 5 times or less of the plating area. It is mentioned to a certain extent that the setting of to suppress the decomposition of the brightener. The insoluble anode refers to an anode that does not dissolve in the plating solution,
Generally, a metal material such as titanium or niobium having a core covered with platinum is used. Some have the surface covered with iridium.

For example, as a brightener for copper sulfate plating, a polymer leveler such as polyethylene glycol and a brightener such as bis (3-sulfopropyl) disulfide are used. Particularly, in jet plating in which air is strongly entrained, brightener is used. The oxidative decomposition of the toner is remarkable, and the balance of the components of the brightener is easily lost. When copper bump contacts are formed with an unbalanced plating solution, they tend to be flatter than normal mushroom-shaped bump contacts, and are more susceptible to the flow of the solution. Becomes larger. If the balance is further lost, the surface of the bump contact loses luster and becomes rough. In the case of a bump contact in which gold is coated on a copper core formed of a plating solution having a brightener that has lost such balance, a contact failure in electrical inspection or a bonding failure with an IC chip in semiconductor mounting occurs.

[0007] Also, compared to plating solutions such as gold plating, which have a good adhesion, the plating solution containing a brightener tends to catch air bubbles, and this is particularly remarkable in a jet plating apparatus in which an object to be plated is directed downward and the solution is sprayed from below. is there. Due to the bubbles, the bump contact does not grow, or if the bump contact grows, the height is insufficient or deformed. Therefore, similarly to the above, the contact failure in the electrical inspection and the bonding failure with the IC chip in the semiconductor mounting are caused. Occur.

An object of the present invention is to solve the above problems and to provide a method of manufacturing a circuit board having bump contacts in which abnormal deposition and uneven height are suppressed, and a jet plating apparatus used therefor.

[0009]

The method of manufacturing a circuit board having bump contacts according to the present invention has the following features. (1) A conductive circuit provided on an insulating substrate is used as a cathode, an anode is provided in a plating solution stored in a storage tank, and a conductive circuit serving as a cathode is exposed above an interface of the plating solution. A method for manufacturing a circuit board having bump contacts, wherein a jet port is disposed below an interface of a liquid, and a plating solution is jetted from the jet port to a cathode to perform electrolytic plating to form a bump contact on a cathode surface.

(2) The method for manufacturing a circuit board having bump contacts according to the above (1), wherein the conductive circuit exposed in the through hole provided at the position where the bump contacts of the insulating substrate are to be formed is a cathode. .

(3) The bump according to (1), wherein the plating solution is a copper sulfate plating solution, and the distance between the interface of the copper sulfate plating solution stored in the storage tank and the jet port is 5 mm to 40 mm. A method for manufacturing a circuit board having contacts.

(4) Plating spouted from one spout
The flow rate of the solution is 30L / hr-200L / hr, the temperature of the plating solution
Is 20 ° C to 30 ° C, and current density is 10A / dm^Two~ 20A
/ Dm ^TwoThe bump contact described in (3) above is set to
Of manufacturing a circuit board having the same.

The jet plating apparatus of the present invention has the following features. (5) A plating apparatus capable of using a conductive circuit provided on an insulating substrate as a cathode, depositing a contact material on a cathode surface to form a bump contact, and a storage tank for storing a plating solution; A jet port provided at a position below the interface of the plating solution, an anode is provided at a position inside the plating solution, and the jet port is capable of jetting the plating solution to the cathode. Jet plating equipment.

(6) 5 points from the position of the interface of the plating solution
The jet-type plating apparatus according to the above (5), wherein the jet port is provided at a position separated by from mm to 40 mm.

(7) The cathode according to (5), wherein the cathode to be plated by the jet plating apparatus is a conductive circuit exposed in a through hole provided at a position where a bump contact is to be formed on the insulating substrate. A jet plating apparatus as described in the above.

(8) The jet plating apparatus according to the above (5), wherein a plate-like object provided with an opening through which the cathode can be exposed is provided between the cathode and the storage tank.

(9) A slit and a groove connected to the opening are provided so as to intersect and connect with each other in the thickness direction from the surface corresponding to the storage tank for the plate-like material. The jet plating apparatus according to the above (8), wherein both or one of the jet plating apparatuses is configured to be able to send the jetted plating solution to the outside of the storage tank.

(10) It has a jet treatment tank and a supply tank,
The jet processing tank is one in which the jet processing of the plating solution is performed in the processing tank, and is capable of storing a storage tank therein, and stores the plating solution after electrolytic plating. The jet plating apparatus according to the above (5), wherein the plating tank is supplied to a supply tank, and the supply tank stores the plating solution supplied from the jet processing tank, and supplies the plating solution to the storage tank.

(11) The jet plating apparatus according to the above (10), wherein the interface between the plating solution in both the jet treatment tank and the supply tank or one of the tanks is filled with nitrogen gas.

[0020]

According to the present invention, a jet port is disposed below an interface of a plating solution stored in a storage tank, a conductive circuit serving as a cathode is exposed above an interface of the plating solution, and a plating solution is supplied to the cathode from the jet port. Are sprayed to perform electrolytic plating, and a contact material for bump contacts is deposited on the cathode surface to form bump contacts, thereby manufacturing a circuit board having bump contacts. Therefore, the entrapment of air bubbles in the plating solution can be suppressed. In particular, it is useful when a plating solution containing a brightening agent in which bubbles are easily caught is used. In this case, it is also possible to suppress oxidative decomposition of the brightening agent component. Further, since the electrolytic plating can be performed in a nitrogen gas atmosphere, the oxidative decomposition of the brightener component can be more significantly suppressed.

[0021]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below in detail with reference to the drawings. FIG. 1 is a cross-sectional view showing an example of a method for manufacturing a circuit board having bump contacts according to the present invention and a jet plating apparatus used for the method, showing a state in which bump contacts are formed by electrolytic plating. The cross section of the plate material forming the conductive circuit 4 and the jet port 2 is hatched.

As shown in the example of FIG. 1, the jet plating apparatus can use a conductive circuit 4 provided on an insulating substrate 3 as a cathode. The jet plating apparatus has a storage tank 1 for storing a plating solution 8 and a jet port 2 provided at a position below an interface of the plating solution 8. Plating solution 8
The anode 12 is provided at a position inside the. Using this jet plating apparatus, the conductive circuit 4 serving as a cathode is exposed above the interface of the plating solution 8 in opposition to the jet port 2, and the plating solution is jetted from the jet port 2 to the cathode to perform electrolytic plating. Is performed, bump contacts 6 are formed on the cathode surface, and a circuit board is obtained.

In the example of FIG. 2, the conductive circuit 4 exposed in the through hole 5 provided at the position where the bump contact 6 of the insulating substrate 3 is to be formed is a cathode. The conductive circuit 4 is further covered with an insulating coating 7. Spout 2
Is formed by providing a through hole in a plate material. Anode 12
Is a box-shaped block 1 installed under the interface of the plating solution 8
1 is installed. A hole (not shown) for conduction with the plating solution 8 is provided on the upper surface of the block 11.

The jet plating apparatus further has a jet processing tank 9 and a supply tank 10. The storage tank 1 is housed inside the jet processing tank 9, and receives the supply of the plating solution from the supply tank 10. Between the cathode and the storage tank 1, there is provided a plate 13 having an opening 14 through which the cathode can be exposed. The insulating substrate 3 is provided on the jet processing tank 9 with a plate-like material 13.
And a rubber sheet 17. The rubber sheet 17 also has an opening connected to the opening 14. The plate 13 is provided with slits (not shown) and grooves 15 in addition to the openings 14.

The plating solution jetted toward the cathode is guided to the outside of the storage tank 1 by the slits and the grooves 15 and stored in the jet processing tank 9. The stored plating solution is sent to the supply tank 10 by the connection pipe 25. The supply tank 10
The plating solution is sent out to the storage tank 1 again. In the jet processing tank 9 and the supply tank 10, nitrogen gas 20 is supplied to the inlet 2.
1 and 23, and the nitrogen gas 20 is supplied from the exhaust port 2
It is discharged from 2,24. Jet treatment tank 9 and supply tank 1
The pressure within 0 is maintained at atmospheric pressure. The supply tank 10 is provided with a heater and a cooler (not shown).
The plating solution is kept at an appropriate temperature. A rubber sheet 18 and a push plate 19 are sequentially provided on the insulating coating 7, and a pressure is applied to the push plate 19 so as to suppress liquid leakage from the jet processing tank 9.

The material of the insulating substrate to be processed is not particularly limited as long as it can stably support the conductive circuit and the bump contact and has substantially electric insulating properties. In order for the bump contact to flexibly follow and come into contact with a contact target portion such as an IC chip, a material having flexibility is preferable. Such materials include polyester resins, epoxy resins, urethane resins, polystyrene resins, polyethylene resins, polyamide resins,
Thermosetting resin or thermoplastic resin such as polyimide resin, acrylonitrile-butadiene-styrene (ABS) copolymer resin, polycarbonate resin, silicone resin, fluorine resin, etc., among them, heat resistance, heating Polyimide-based resins which are excellent in dimensional stability and mechanical strength due to the above are particularly preferably used.

Although the thickness of the insulating substrate is not particularly limited, it is 2 μm to 500 μm, preferably 5 μm to 150 μm in order to have sufficient mechanical strength and flexibility.
It is preferable to set m. Another type of resin layer may be laminated on the surface of the insulating substrate on the side where the bump contacts are provided, depending on the application. If a semiconductor chip is mounted using a circuit board having bump contacts on which such a resin layer is laminated, the circuit board having bump contacts and the semiconductor chip can be sealed without a separate step after mounting. It is preferred. As a material of the resin layer, a known material such as an epoxy resin or a silicone resin may be used.

The conductive circuit is provided on an insulating substrate. The conductive circuit serves as the cathode in the present invention and is exposed above the interface of the plating solution. The conductive circuit as referred to in the present invention is a broad concept including not only wiring patterns but also electrodes and leads. The material of the conductive circuit is not particularly limited as long as it is a material having conductivity, for example, a metal, but is preferably a material of a circuit pattern on a known circuit board. Accordingly, copper having a small resistance is preferable because the wiring width is reduced and the signal needs to be operated at high speed. The thickness of the conductive circuit is not particularly limited, but is preferably 1 μm to 200 μm, and particularly preferably 5 μm to 80 μm.

The conductive circuit can be provided on the insulating substrate by a method such as electroless plating or sputtering on the insulating substrate, or by coating an insulating substrate in a varnish state on a copper foil or the like serving as the conductive circuit. And a method of bonding a film-shaped conductive circuit and an insulating substrate with an adhesive.

[0030] The conductive circuit may be further covered by an insulating coating. That is, as shown in FIG. 1, the conductive circuit 4 is sandwiched between the insulating substrate 3 and the layer of the insulating film 7. As the material of the insulating film, any material may be used as long as it has electrical insulation. When a circuit board having this insulating film is used as it is as a product, it is preferable that the material of the insulating film is the same as the material of the insulating substrate, whereby the coefficient of linear expansion between the insulating substrate and the insulating film is reduced. As a result, problems such as curling and dimensional shrinkage due to temperature change are eliminated.

If this insulating film is used as a primary resist film for electrolytic plating, a known resist film material may be used as the material of the insulating film. Among them, those which are easily peeled off after electrolytic plating and have no current leakage at the time of electrolytic plating are preferable. In particular, a heat-resistant vinyl chloride resist is preferable because it can be mechanically peeled by adjusting the amount of the plasticizer without current leakage. As a method for forming the insulating film, a method similar to the method for forming the conductive circuit on the insulating substrate described above can be used.
When the insulating film is a vinyl chloride resist, it can be formed by screen printing.

Examples of the method of forming a through hole in an insulating substrate include a mechanical perforation method such as punching, photolithography, plasma processing, chemical etching, and laser processing. Is preferably laser processing capable of fine processing, and it is particularly preferable to use perforation processing using an ultraviolet laser having an oscillation wavelength in the ultraviolet region. The shape of the opening of the through hole, that is, the shape of the cross section perpendicular to the longitudinal axis of the through hole is not limited, but a circular shape is preferable. The diameter of the through hole is φ5μm
To φ200 μm, particularly preferably about φ8 μm to φ100 μm.

After the through holes are formed as described above, if burrs or decomposed substances are adhered to the insulating substrate in the vicinity, a wet desmear treatment with permanganic acid is performed before plating is started. Or dry desmear treatment with plasma. If burrs or decomposed substances are present near the through-holes, plating will be deposited using them as nuclei,
The shape of the bump contact is not preferable because it does not form a mushroom shape. Desmear treatment refers to removal of burrs and decomposed materials.Wet desmear treatment with permanganic acid
Burrs and decomposed products are removed as manganese oxide residues, and plasma-induced dry desmear treatment removes burrs and decomposed products as carbon dioxide.

When the through-hole is fine or the insulating substrate is hydrophobic, the plating solution does not enter the through-hole, so that the bump contact may not grow. Therefore, it is preferable that the insulating substrate be subjected to a hydrophilic treatment for providing oxygen with plasma or the like. The hydrophilization treatment refers to improving the wettability with water. It is preferable that the wettability of the insulating substrate be 20 degrees or less in terms of the contact angle with pure water before the start of plating and before processing such as soft etching performed before the plating. If the wettability is greater than 20 degrees, the diameter 20
This is because the plating solution may not enter the through holes having a thickness of about 200 μm to about 200 μm and a depth of about 5 μm to about 50 μm, and the bump contacts may not grow. Soft etching refers to a process for removing a metal oxide film of a conductive circuit exposed in a through hole and securing adhesion to a plating metal.

The contact material filling the inside of the through-hole and the contact material forming the bump contact are not particularly limited as long as they can be deposited by electrolytic plating, and known metal materials can be used. For example, gold, silver, copper, platinum, lead,
Single metals such as tin, nickel, cobalt, indium, rhodium, chromium, tungsten, and ruthenium, or various alloys containing these as components, such as solder, nickel-tin, and gold-cobalt.

Of the above examples, the present invention is useful for contact materials deposited by a plating solution containing a brightener, for example, copper deposited from a copper sulfate plating solution and nickel deposited from a Watts bath, Of these, copper is particularly useful.

In the above description, the brightener contained in the plating solution is not limited, and may be any brightener generally used for electrolytic plating. For example, polyether compounds such as polyethylene glycol, polypropylene glycol, and polyvinyl alcohol; sulfur-based organic compounds such as bis (3-sulfopropyl) disulfide and bis (p-sulfophenyl) disulfide; and nitrogen-based organic compounds such as azo dyes and phthalocyanine dyes. Compounds, thiourea, thiocarbazonic acid derivatives and the like.

As the structure of each bump contact, the surface of the bump contact, which is a good conductor such as copper or nickel and is formed of an inexpensive metal material, is formed on the surface of the bump contact, depending on the application, with a high-hardness metal or material. And a structure in which a stable metal film (surface layer) is formed. Such noble metals include various noble metals. For example, it is preferable to use gold or the like, which is chemically stable and has high contact reliability, for bonding to a semiconductor element, and rhodium, ruthenium, or the like having high hardness for electrical inspection such as burn-in.

The height of the bump contact is not particularly limited, but is preferably about 1 μm to 100 μm. However, this value is a nominal dimension of the height of the bump contact, and the height of the bump contact formed on the same insulating substrate has a variation in height regardless of the nominal dimension. Ideally it should be zero. In actual use, the height variation of the bump contact may be within ± 2 μm, but the tolerance range of the variation may be set freely according to the application. In addition, the height of the bump contact generally refers to the height up to the top of the bump contact with respect to the surface of the insulating substrate.

Plating conditions for forming bump contacts,
That is, the flow rate of the plating solution, the plating solution temperature, and the current density may be appropriately set according to the type of the object to be plated or the plating solution, and are not particularly limited. However, it is preferable that the setting be made so that a bump contact capable of performing good bonding and contact can be formed. In the present invention, since the jet-type electrolytic plating is performed, the flow rate of the plating solution with respect to the object to be plated can be increased, and the current density can be set higher. Therefore, bump contacts can be formed at high speed.

For example, when the plating solution is a copper sulfate plating solution containing a brightener, the flow rate of the plating solution ejected from one jet port is preferably set to 30 L / hour to 200 L / hour. If the flow rate of the plating solution is less than 30 L / hour, the bump contacts are liable to come off, and if the flow rate exceeds 200 L / hour, the decomposition rate of the brightener becomes undesirably high.

In a similar case, the temperature of the plating solution is 2
It is preferable to set the temperature at 0 ° C to 30 ° C. 20
If the temperature is lower than 30 ° C., it is difficult to perform high-speed deposition, and bump deformation is likely to occur.

In the case of a copper sulfate plating solution having a flow rate of 100 L / hour and a temperature of 25 ° C., the current density is 10 A / dm.
^It is preferred to be ^{2 to} 20 A / dm ² . Current density is 1
If it is less than 0 A / dm ² , the shape of the bump contact tends to be flat, which is not preferable. If it exceeds 20 A / dm ² , the plating solution tends to bite the air bubbles, so that the bump contacts come off. Further, if the air bubbles come off during the growth of the bump contacts, the height of the bump contacts becomes insufficient or the marks of the air bubbles are left. It is not preferable because it is attached to the bump contact. Also, the cross-sectional shape of the bump contact becomes elliptical with respect to the circular through hole, which is not preferable. Here, the occurrence of a dropout in a bump contact refers to a state in which plating does not grow. Specifically, since electrolytic plating is performed in a solution, fine through-holes are apt to bite air bubbles, and the bubbles do not allow the plating solution to enter the through-holes, so that plating does not grow.

If the plating solution is a watt bath, the flow rate of the plating solution is set to 30 L / hour to 200 L / hour per jet port, and the temperature of the plating solution is set to 30 ° C. to 80 ° C. The current density is preferably set to 3 A / dm ^{2 to} 20 A / dm ² .

The components of the jet plating apparatus will be described below. The setting conditions such as the size and shape of each part are as follows: a copper sulfate plating solution containing a brightener is used as a plating solution, and the flow rate of the plating solution per jet port is 30 L / hour or more.
The case where 200 L / hour, the temperature of the plating solution is 20 ° C. to 30 ° C., and the current density is 10 A / dm ^{2 to} 20 A / dm ² is described.

The storage tank may be any storage tank that can store the plating solution and has an upper opening so as not to hinder the jet of the plating solution. The shape, volume and the like may be set according to the purpose. Examples of the shape of the storage tank include a hollow cube with a bottom, a rectangular parallelepiped, and a column.

FIG. 3 shows a top view of the storage tank. FIG. 2A shows a case where the supply ports 26 are provided at two places.
FIG. 2B shows a case where the number of supply ports 26 is four. FIG. 4 shows a top view of a hollow cylindrical storage tank having a bottom. FIGS. 7A, 7B, and 7C show the case where the number of supply ports 26 is two to four. In both figures, the arrows indicate the flow of the supplied plating solution.

As shown in FIG. 3, the plating solution is supplied to the storage tank at two or four locations provided at equal intervals in the storage tank if the shape of the storage tank is a hollow cube having a bottom. This is preferably performed from the supply port 26. If the shape of the storage tank is cylindrical as shown in FIG.
It is preferable to start from 6. If the number of the supply ports 26 is other than this, the liquid pressure of the plating solution to be jetted varies, and therefore, the height of the bump contact also varies, which is not preferable. Supply port 2
As shown in FIGS. 3 and 4, when the shape of the storage tank is a cube or a column and is a square as viewed from the front, the position 6 is preferably a point-symmetric position with respect to the center of the storage tank.

FIG. 5 is a view showing an insulating substrate to be processed, which is shown in a plan view. In the figure, a plurality of through holes (not shown) are arranged such that the center of the through holes is located on the side of a square having a side of 10 mm, and only this square is illustrated. A plurality of through-holes located on the side of one square arranged as described above are defined as one piece. In FIG. 3A, four pieces of through holes are formed.
The case where a piece is processed by one plating is shown. When the inter-piece pitch is 20 mm, the distance between the ends of the sample is 30 mm. FIG. 9B shows a case where nine pieces of through holes are formed and the nine pieces are processed by one plating. In this case, the nozzle area is wide, and 50 mm from end to end.

When the nozzle area, that is, the area to be treated by one plating is increased, the central portion of the storage tank and the outer peripheral portion thereof have a variation in hydraulic pressure, and the central hydraulic pressure tends to increase. In this case, the block 11 can be canceled by installing the block 11 in the central part of the storage tank as shown in FIG. Further, the block 11 is formed into a hollow box shape,
A current distribution can be controlled by installing an anode therein, providing a hole (not shown) for conduction with a plating solution on the upper surface of the block, and changing the size and arrangement of the hole.

The jet outlet is for jetting the plating solution upward, and may be any opening provided below the interface of the plating solution stored in the storage tank and for jetting the plating solution to the cathode. Specifically, the opening on the cathode side of the through-hole provided in the plate member as shown in FIG. FIG. 6 is a sectional view showing the jet port 2 and the plate member 62. The shape of the through hole 61 provided in the plate member 62 may be a convex shape as shown in FIG. 6A, or may be a tapered hole as shown in FIG. 6B. 8a shows the flow of the plating solution

When there are a plurality of cathodes, the plating solution may be jetted to each of the cathodes individually, or may be jetted to a plurality of cathodes at one jet port. The shape of the jet port is not particularly limited, and may be a circle, a square, or another polygon, but a circle is preferable from the viewpoint of easy processing.

The size of the jet port may be determined in accordance with various conditions such as the flow rate of the plating solution, the size of the through-hole provided in the insulating substrate to be processed, and the like. The example shown in FIG. 7 will be described. FIG. 3 is a diagram showing an arrangement of through holes 5 provided in an insulating substrate to be processed. In the figure, the plating solution is ejected from one jet port to all the through holes 5, and the through holes 5 are arranged such that the center thereof is located on the side of the square. For example, in the range where the maximum distance L between the through holes is 20 mm or less, the size of the jet port (for example, the diameter if the shape is circular, or the diagonal length if the shape is a polygon such as a square) Is a maximum value of 0.2 times the maximum distance L between the through holes.
One time is preferred. If it is less than 0.2 times, the amount of the plating solution to be jetted is small, so that bubbles in the through-holes where the conductive circuit serving as the cathode is exposed do not come out and bump contacts do not grow, which is not preferable. If it is larger than 1 time, the pressure of the plating solution jetted is low, so that bubbles in the through holes do not escape and bump contacts do not grow, which is not preferable.

It is preferable that the jet port is provided at a position 5 mm to 40 mm below a position which is an interface of the plating solution. If the thickness is less than 5 mm, the air bubbles are strongly caught in the plating solution, and the brightener is rapidly decomposed. If the thickness exceeds 40 mm, the liquid pressure on the portion to be plated, that is, the bump contact deposition portion becomes small, and it is not preferable because bubbles in the through holes provided in the insulating substrate cannot be removed and bumps may be removed.

It is preferable that a plate-like material is provided between the cathode and the storage tank as shown in FIG. The plate-shaped material may be any one provided with an opening so as not to hinder the jet of the plating solution to the cathode. The plate-like object may be installed using a jet processing tank or the like. In the example of FIG. 1, the plate-like object is installed on the upper part of the jet processing tank 9, and the insulating substrate 3 and the storage tank 1 are provided.
And is located between. As shown in FIG. 1, a rubber sheet 17 or the like may be provided between the plate 13 and the insulating substrate 3, but there is no gap between these and the rubber sheet 17 or the like. Is preferred. It is preferable that the plate-like object is provided with a slit and a groove.

FIG. 2 is a perspective view showing an example of a plate-like object.
Only a part of the plate is shown. The plate-like object shown in the figure is shown with the surface facing the storage tank facing upward. As shown in the figure, a plurality of openings 14 are provided in the plate 13 so as to expose the cathode. A slit 16 and a groove 15 are provided in the thickness direction from the surface of the plate-shaped object facing the storage tank. The slit 16 penetrates the plate 13 in the thickness direction and is connected to the plurality of openings 14. Groove 15
Passes through the center between the openings, intersects with the slit 16, and is connected. The groove 15 is a long and narrow groove, and is a discontinuous groove at a portion that intersects with the slit 16. By providing such slits 16 and grooves 15, the ejected plating solution is sent to the outside of the storage tank through the slits 16 and grooves 15.

It is preferable that the plate is placed so that a gap is provided between the plate and the storage tank. Under the plating conditions described above, the gap is preferably set to be 0.2 mm to 2 mm. If the gap is less than 0.2 mm, the amount of the plating solution flowing to the outside of the storage tank through the space between the storage tank and the plate after the jet flow becomes non-uniform, so that the height of the bump contact is preferably varied. Absent. When the gap exceeds 2 mm, the pressure of the jetted plating solution at the cathode becomes low, and the bump contacts are undesirably dropped.

The thickness of the plate is preferably 5 mm to 30 mm. If the thickness is less than 5 mm, the opening is shallow, and the height of the bump contact varies greatly, which is not preferable. The plate is pressed as shown in FIG.
If it is less than mm, it will be distorted depending on the material. For this reason, the gap between the plate-like material and the storage tank cannot be kept constant, and the amount of the plating solution flowing to the outside of the storage tank becomes non-uniform as described above, and the height of the bump contact varies, which is not preferable. If the thickness is more than 30 mm, the pressure of the jetted plating solution at the portion to be plated becomes low, so that the bubbles in the through-holes where the conductive circuit is exposed do not come out and the bump contacts do not grow, which is not preferable.

The opening may be provided so as not to hinder the jetted plating solution. If the plating solution is ejected separately for each cathode, one opening may be provided for one cathode. On the other hand, if the plating solution is ejected from one jet port to a plurality of cathodes, one opening may be provided so that the plurality of cathodes are exposed.

The size of the opening may be determined as appropriate according to the number of through holes where the conductive circuit is exposed, the size of the through holes, and the arrangement length of the through holes. For example, in the example of FIG. 7 described above, when the maximum distance L between the through holes is in the range of 20 mm or less, the size of the opening (for example, if the opening has a circular shape, the diameter and the opening In the case of a polygon such as a square, the maximum value of the diagonal length is the same. The same applies hereinafter) is preferably 1.1 to 2 times the maximum distance L between the through holes. If it is less than 1.1 times, it becomes difficult to position the opening and the corresponding cathodes, which is not preferable. If it exceeds twice, the height variation of the bump contacts becomes large, which is not preferable.

It is preferable that the number of connection points between the opening and the slit is two or four. If there are two connection positions, the connection position is a position where the two slits face each other, and is preferably a position where the distance between the slits is minimized. If there are four connection points, the connection position of the slit is a position that equally divides the opening, and a position that minimizes the distance between the opposed slits is preferable. For example, as shown in FIG.
If the shape of 4 is a quadrangle, it is preferable that the midpoint of the side of the opening 14 be the connection position. When the connection position is set so that the distance between the slits 16 is maximized, for example, in the case where the slit 16 is connected to an arbitrary corner position of a square in FIG. 1
The liquid pressure at the four corners of No. 4 becomes small, and the height of the bump contact becomes low, which is not preferable.

The slit may be formed in the thickness direction of the plate-like object, may be connected to the opening, and may be connected to the groove so as to guide the jetted plating solution to the groove. The plating solution may be able to move the plating solution to the outside of the storage tank. Through hole 5 provided in insulating substrate
In order to remove bubbles in the vicinity, it is preferable that the slit 16 penetrates the plate 13 in the thickness direction and connects the openings 14 as shown in FIG.

The width of the slit is preferably 0.05 to 0.3 times the size of the opening under the above plating conditions. If it is less than 0.05 times, the flow of the plating solution is poor and bubbles in the openings do not escape, so that the bump contacts cannot grow to the required height, which is not preferable. If it exceeds 0.3 times, the height of the bump contact becomes uneven, which is not preferable.

The groove may be formed so as to intersect and be connected to the slit, and may be any as long as it can move the jetted plating solution to the outside of the storage tank. The groove may be connected to the opening, but is preferably not connected. The width of the groove, under the plating conditions described above,
It is preferably at least one time the width of the slit and at most 0.8 times the distance between the openings. The width of the groove is 1 of the width of the slit
If the ratio is less than twice, the growth of the bump contact becomes insufficient, which is not preferable. If the distance is more than 0.8 times the distance between the openings, the strength of the plate-like object cannot be maintained, which is not preferable. The depth of the groove is 2
mm or more and 0.8 times or less the thickness of the plate-like material. If the depth of the groove is less than 2 mm, the flow of the plating solution is poor, and the growth of the bump contact is insufficient, which is not preferable. If the thickness is more than 0.8 times the thickness of the plate, the strength of the plate cannot be maintained, which is not preferable. The position of the groove may be any position as long as the plating solution can be moved to the outside of the storage tank.

The jet plating apparatus of the present invention is preferably provided with a jet processing tank and a supply tank. The jet processing tank is for performing a jet processing of a plating solution in the processing tank and capable of accommodating a storage tank therein, and stores a plating solution after being jetted and subjected to electrolytic plating. Anything should do. Further, the jet processing tank is connected to the supply tank, and may be any one that sends the stored plating solution to the supply tank. The connection between the jet processing tank and the supply tank may be made by an existing tube or tube. The shape of the jet processing tank is not particularly limited, and may be appropriately determined. The shape of the jet processing tank is a hollow cube with a bottom, a rectangular parallelepiped,
Columns and the like can be mentioned. The volume of the jet processing tank is not particularly limited either, and may be appropriately determined. The material for forming the jet treatment tank may be any material that does not leak the plating solution and is not easily affected by the plating solution, and known resins and metals can be used.

The pressure in the jet treatment tank is preferably about atmospheric pressure, and preferably does not fluctuate. Therefore, it is preferable that the jet treatment tank is not hermetically sealed and can perform natural ventilation. For example, when the jet processing tank 9 is sealed in FIG. 1, when the plating solution is pumped to the storage tank 1 and the jetted plating solution returns to the supply tank 10, the gas such as air in the jet processing tank 9 is collected together. Therefore, the pressure in the jet processing tank 9 is reduced, and the insulating substrate 3 formed of a flexible material is deformed, and the opening 14 of the plate 13 is undesirably wrinkled. In addition, since hydrogen gas and mist are generated during plating in the jet processing tank, it is necessary to eliminate them. However, if these are eliminated by forced ventilation instead of natural ventilation, the jet processing tank will It is difficult to keep the oxygen concentration constant.

The supply tank may store the plating solution sent from the jet processing tank and supply the plating solution to the storage tank, provided that a supply pump is provided inside or outside the tank. good. The supply tank may be appropriately provided with a flow meter, a filter, and the like inside and outside. The supply of the plating solution to the storage tank may be performed using an existing tube or tube. The shape of the supply tank is not particularly limited, and may be determined as appropriate. Examples of the shape of the supply tank include a hollow cube with a bottom, a rectangular parallelepiped, and a column. The volume of the supply tank is not particularly limited either, and may be appropriately determined. The material of the supply tank may be any material as long as the plating solution does not leak and is not easily affected by the plating solution, and a known resin or metal can be used.

It is preferable that the jet processing tank and the supply tank are supplied with nitrogen gas. The purity of the nitrogen gas may be 99.9% or more. The supply amount of the nitrogen gas is preferably 0.2 m ³ / h or more per 1 m ^{3 of the} space not occupied by the plating solution in the jet processing tank or the supply tank. The volume of the space not occupied by the plating solution in the jet processing tank and the supply tank is 0.0001 m ³ to 0.01 in the case of the jet processing tank.
m ^3, preferably set to about 0.01 m ³ to 1 m ³ if the supply tank. Further, in this case, it is preferable to supply the nitrogen gas such that the oxygen concentration in the space becomes 1% or less.

If the nitrogen gas supply rate is less than 0.2 m ³ / hour, it is difficult to maintain the oxygen concentration at 1% or less when natural ventilation is performed in the jet processing tank or the supply tank, which is not preferable. . If the oxygen concentration exceeds 1%, the brightener component contained in the plating solution undergoes oxidative decomposition, and the component balance of the brightener tends to be lost. If the component balance of the brightener is lost, the shape of the bump contact becomes flat instead of the mushroom shape, or the apex thereof is deviated by the flow of the plating solution, and the height of the bump contact varies, which is not preferable. Furthermore, if the component balance of the brightener is lost, the surface of the bump contact loses luster,
It is not preferable because the surface becomes rough.

The rubber sheet provided between the insulating substrate and the plate-like material has an opening so as to prevent the liquid from leaking from the jet processing tank and to prevent the jet to the cathode similarly to the plate-like material. Is good. Examples of the material of the rubber sheet include silicon rubber and fluorine rubber, and these may be used as appropriate. However, fluororubber is preferable because of its excellent sealing property with the insulating substrate and chemical resistance.

In the case where the jet plating apparatus is continuously processed in a hoop shape, the rubber sheet (the rubber sheet 17 shown in FIG. 1; the same applies hereinafter) between the insulating substrate and the rubber sheet is smoothly removed. It is preferable to roughen the surface with a paper file or the like, or to use an elastic sponge or the like as a material for the rubber sheet. Unless the insulating substrate and the rubber sheet can be smoothly detached from each other, wrinkles are generated on the insulating substrate, which is not preferable. Further, in the continuous processing, if the attachment and detachment cannot be performed smoothly, the position of the exposed cathode is shifted with respect to the opening provided in the plate-like object, and it is not preferable because bump contacts are not formed.
Here, the continuous processing in a hoop shape refers to a hoop-shaped substrate,
For example, a substrate having a width of 125 mm and a length of 5 m or more is continuously fed, and a series of plating steps (for example, soft etching, water washing, copper plating, water washing, drying, or soft etching, water washing, gold strike, water washing, gold plating, Washing and drying) to form bump contacts.

The opening provided in the rubber sheet preferably has the same shape and the same size as the opening of the opening provided in the plate. If the opening is smaller than the opening provided in the plate-like object, the conductive circuit partially covers the exposed through hole, and the probability that the bump contact cannot be completely grown increases, which is not preferable. Conversely, if it is large, air bubbles tend to adhere to the gap between the plate-like object and the insulating substrate, and the bump contact cannot grow, which is not preferable. A slit similar to the slit provided on the plate-like material may be formed on the rubber sheet. When the slit is not formed in the rubber sheet, the thickness of the rubber sheet is preferably set to 3 mm or less. If the thickness of the rubber sheet exceeds 3 mm, bubbles near the through holes are difficult to remove, and the bump contacts may not be completely grown, which is not preferable.

The outer dimensions of the rubber sheet (the rubber sheet 18 shown in FIG. 1; the same applies hereinafter) arranged below the pressing plate are larger than the outer dimensions of the rubber sheet than the edges of the openings and slits provided in the plate-like object. Is preferably set to be larger than the edge by 4 mm. If the thickness is less than 4 mm, the plating solution is likely to leak when the plating solution is jetted, which is not preferable. Further, the outer dimensions of the rubber sheet may be widened so as not to cover a through hole of a sprocket or the like provided on the insulating substrate for transportation in the case of continuous processing in a hoop shape. It is not preferable that the rubber sheet covers such a hole because a liquid leaks from the hole.

[0074]

EXAMPLES The present invention will be specifically described below with reference to examples. A circuit board having bump contacts was actually manufactured using the jet plating apparatus shown in FIG.

Example 1 A 35 μm thick copper foil was coated with a polyimide precursor solution so that the thickness after drying was 25 μm. This was dried and cured to produce a two-layer film of a copper foil and a polyimide film as an insulating substrate. Next, after forming a resist layer in a circuit pattern on the surface of the copper foil, a conductive circuit having a desired circuit pattern was formed using a photo process.

An oscillation wavelength of 248 nm is provided on the back surface of the conductive circuit at a position where a bump contact of a polyimide film is to be formed.
Then, dry etching was performed by irradiating a KrF excimer laser beam through a mask to form 208 through holes.
A conductive circuit was exposed on the inner bottom surface of each through hole to serve as a cathode. The center of the through hole has a side length of 7 mm.
Are formed on the sides of the square. The 208 through-holes thus formed were made into one piece, and further, a total of 30 pieces of through-holes were formed on the insulating substrate by arranging 5 pieces vertically and 6 pieces horizontally. The diameter of the inner bottom surface of each through hole is 50 μm, and the opening diameter is 60 μm.
Met.

Next, oxygen plasma is applied to the through-holes, and the copper foil exposed to the through-holes is further treated with a sodium persulfate-based soft etching solution and washed with pure water (2 μS / cm or less). Copper sulfate plating was performed under the plating conditions and plating apparatus shown in FIG.

[Plating conditions] The components of the plating solution were as follows: 1 g of the plating solution, 70 g of copper sulfate; sulfuric acid;
190 g, additive (Uemura Kogyo Co., Ltd.) Sulcup AC9
0; 20 mL, and chlorine was further added to a concentration of 60 ppm. The operating conditions for performing the jet-type electrolytic plating include: a flow rate per jet port; 100 L / hour;
Temperature of plating solution; 25 ° C., current density: 15 A / dm ² ,
Plating time: 10 minutes. One jet was performed per piece.

[Plating Apparatus] The conditions of the jet plating apparatus were as follows: amount of plating solution: 200 L, size inside jet processing tank (length × width × height): 0.1 mx 0.5 mx 0.5
m, the volume of the space not occupied by the plating solution in the jet processing tank; 0.015 m ³ , the size inside the supply tank (length × width × height): 0.5 m × 0.5 m × 1.0 m, supply The volume of the space not occupied by the plating solution in the tank: 0.07 m ³ .

The plate-like object was prepared in the shape shown in FIG. 2, and the set values of each part were as follows: the thickness of the plate-like object: 15 mm, the opening: a square having a side of 14 mm, the width of the slit: 2 mm, the groove Width: 4 mm, groove depth: 10 mm. Note that the openings are formed such that one opening corresponds to one piece.
Provided. The slit is formed to penetrate the center of two opposing sides of the adjacent opening. The groove is formed so as to pass through the center between the adjacent openings and to vertically intersect the slit.

The rubber sheet disposed between the plate-like material and the insulating substrate is a fluororubber sheet having a thickness of 1 mm, and the rubber sheet disposed below the pressing plate is a sponge-shaped fluororubber sheet having a thickness of 5 mm. And The spout has a diameter of φ4
mm so that one jet can flow per piece.
0 were formed. At this time, the center of the square formed by connecting the centers of the through holes formed in one piece corresponded to the center of the jet port. The jet port was set so that the distance from the interface of the plating solution stored in the storage tank was 20 mm. The storage tank has an outer shape of a rectangular parallelepiped and an inner size of 11 mm.
It was set to 0 mm x 88 mm x 150 mm. The storage tank was installed such that the gap between the storage tank and the plate was 1 mm. There were two supply ports for supplying the plating solution to the storage tank, and these were installed at positions facing each other on the side surface of the storage tank.

[Evaluation of Circuit Board Having Bump Contact] The formed bump contact had a glossy surface, and had a mushroom shape. The vertex of the bump contact was located at the center of the diameter of the bump contact, no abnormality was observed, and the deviation of the vertex was 5% or less. Note that the shift amount is obtained by the following equation. (Equation) Displacement amount = (R−Radius of bump contact) / Diameter of bump contact × 100 R: Maximum distance from outer periphery of bump contact to vertex of bump contact

Next, the height of the bump contact from the surface of the insulating substrate was measured. Note that the measurement was conducted by arbitrarily selecting one bump contact from each piece and selecting 30 bump contacts.
This was performed for each bump contact. As a result, the height of the bump contact from the polyimide surface was 15 μm on average, 13 μm minimum, and 17 μm maximum. The coefficient of variation relatively representing the variation in the height of the bump contact was 3%. The coefficient of variation is calculated by the following equation. (Equation) Coefficient of variation = Standard deviation / Average × 100 Further, when a circuit board having bump contacts was continuously manufactured under the above conditions, the shape of the bump contacts was a normal mushroom shape for continuous 600 hours. In this embodiment, the normal mushroom shape means that the ratio (h / d) between the height h and the diameter d of the bump contact 6 shown in FIG.
It means the case where it is in the range of 5 to 0.3. FIG. 8 is a sectional view showing a bump contact provided on an insulating substrate.

Example 2 Under the same conditions as in Example 1, the average height of the bump contacts was 5 μm.
Electroplating was performed until the value of m reached. The deviation amount was 5% or less. Next, gold plating was performed, and gold having a hardness of 70 Hv was further deposited on the surface of the bump contact until the thickness became 10 μm to form a bump contact having a two-layer structure of copper and gold. Gold plating conditions are as follows: gold plating solution; S-440: N-Chemcat, temperature of plating solution; 70 ° C., current density: 3.5 A / dm ² , plating time; 6 minutes, flow rate per jet; 1.5 L / min, number of jets; 30
Example 1 except that the diameter of the jet port was 4 mm, the distance between the jet port and the interface of the plating solution was 0 mm, the anode was a platinum mesh.
The same conditions were used. When the thus formed bump contact was joined to an aluminum electrode, no joining failure occurred.

Comparative Example 1 A circuit board having a bump contact was manufactured in the same manner as in Example 1 except that the installation position of the jet port was changed to a position where the distance from the interface of the plating solution was 0 mm. As a result, in the first plating, the average height of the bump contacts is 15 μm,
The shape of the bump contact was a normal mushroom shape.

After the first plating, a jet operation was performed for 1 hour without electrolysis, and then a circuit board having bump contacts was again manufactured. The height of the bump contacts was 10 μm on average, the minimum value was 5 μm, The maximum value was 15 μm, and the coefficient of variation was 7%. The shape of the bump contact was flat, and the apex of the bump contact was shifted in the flowing direction of the plating solution. The shift amount was 10 to 20%, which was more than twice the shift amount of a normal mushroom-shaped bump contact.

Comparative Example 2 Next, electrolytic plating was performed under the same conditions as in Comparative Example 1 until the average height of the bump contacts became 5 μm. The displacement is 1
5%. Electroplating was further performed to deposit gold having a hardness of 70 Hv on the surface of the bump contact until the thickness became 10 μm, thereby forming a bump contact having a two-layer structure of copper and gold. Gold plating was performed under the same conditions as in Example 2. When the bump contact thus formed was joined to an aluminum electrode, a joining failure occurred.

[0088]

According to the present invention, even in the case of performing jet-type electrolytic plating using a plating solution containing a brightening agent, the incorporation of bubbles into the plating solution can be suppressed.
Oxidative decomposition of the brightener component can be suppressed. Therefore, it is possible to suppress the bump contact from becoming a flat shape instead of a mushroom shape, and it is possible to reduce the variation in the height of the bump contact. In addition, it is possible to prevent the apexes of the bump contacts from being biased or from falling off.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view showing an example of a method for manufacturing a circuit board having bump contacts of the present invention and a jet plating apparatus used for the method.

FIG. 2 is a perspective view showing a plate-like object used in the jet plating apparatus of the present invention.

FIG. 3 is a top view of a cubic storage tank used in the jet plating apparatus of the present invention.

FIG. 4 is a top view of a storage tank having a cylindrical shape used in the jet plating apparatus of the present invention.

FIG. 5 is a view showing an insulating substrate to be processed.

FIG. 6 is a cross-sectional view showing a jet port and a plate used in the jet plating apparatus of the present invention.

FIG. 7 is a diagram showing an arrangement of through holes provided in an insulating substrate to be processed.

FIG. 8 is a cross-sectional view illustrating a bump contact provided on an insulating substrate according to the manufacturing method of the present invention.

[Description of Signs] 1 Storage tank 2 Jet port 3 Insulating substrate 4 Conductive circuit 5 Through hole 6 Bump contact 7 Insulating coating 8 Plating solution 9 Jet processing tank 10 Supply tank 11 Block 12 Anode 13 Plate-like object 14 Opening 15 Groove

Claims (11)

[Claims] 1. A conductive circuit provided on an insulating substrate is used as a cathode, and an anode is provided in a plating solution stored in a storage tank.
A conductive circuit, which is a cathode, is exposed above the interface of the plating solution, and a jet port is arranged below the interface of the plating solution. A method for manufacturing a circuit board having a bump contact, comprising: forming a bump contact; 2. The method for manufacturing a circuit board having bump contacts according to claim 1, wherein the conductive circuit exposed in the through-hole provided in the insulating substrate at the position where the bump contacts are to be formed is a cathode. 3. The bump contact according to claim 1, wherein the plating solution is a copper sulfate plating solution, and a distance between an interface of the copper sulfate plating solution stored in the storage tank and the jet port is 5 mm to 40 mm. Of manufacturing a circuit board having the same. 4. A plating solution jetting from one jet port has a flow rate of 30 L / hour to 200 L / hour and a plating solution temperature of 20 L / hour.
° C. to 30 ° C., a current density of 10A / dm ² ~20A / dm
4. The method for manufacturing a circuit board having bump contacts according to claim 3, wherein the value is set to ² . 5. A plating apparatus that can use a conductive circuit provided on an insulating substrate as a cathode, deposits a contact material on a cathode surface to form a bump contact, and a storage tank that stores a plating solution; A jet port provided at a position below the interface of the plating solution, and an anode is provided at a position inside the plating solution, and the jet port is capable of jetting the plating solution to the cathode. Characteristic jet plating equipment. 6. A distance of 5 mm from a position that is an interface of the plating solution.
6. The jet outlet is provided at a position 40 mm away.
A jet plating apparatus as described in the above. 7. The method according to claim 5, wherein the cathode to be plated by the jet plating apparatus is a conductive circuit exposed in a through hole provided at a position where a bump contact is to be formed on the insulating substrate. Jet plating system. 8. A plate-like object having an opening through which the cathode can be exposed is provided between the cathode and the storage tank.
A jet plating apparatus as described in the above. 9. A slit and a groove connected to the opening are provided so as to intersect and connect with each other in a thickness direction from a surface corresponding to the storage tank of the plate-like material, and both the slit and the groove are provided. 9. The jet plating apparatus according to claim 8, wherein at least one of the jet plating apparatuses is configured to send the jetted plating solution to the outside of the storage tank. 10. A jet processing tank having a jet processing tank and a supply tank, wherein the jet processing tank performs jet processing of a plating solution in the processing tank, and can accommodate a storage tank therein. In addition, the plating solution after electrolytic plating is stored and the plating solution is supplied to a supply tank. The supply tank stores the plating solution supplied from the jet processing tank and supplies the plating solution to the storage tank. 6. The jet plating apparatus according to claim 5, wherein 11. The jet plating apparatus according to claim 10, wherein nitrogen gas is filled on the interface of the plating solution in both the jet processing tank and the supply tank or in one of the tanks.