JP4467341B2 - Manufacturing method of multilayer wiring board - Google Patents

Description

The present invention relates to a method for manufacturing a multilayer wiring board, and more specifically, for electrical inspection of a package for storing an electronic component such as a package for housing a semiconductor element for housing a semiconductor integrated circuit element, and a semiconductor integrated circuit. The present invention relates to a method for producing a multilayer wiring board used for a probe card or the like.

  2. Description of the Related Art In recent years, in semiconductor integrated circuits, the number of terminals formed on a semiconductor substrate has increased and the pitch of terminals has been reduced due to higher integration of semiconductor elements and an increase in the number of processing signals. As a result, the pitch of the connection terminals of the package for housing the semiconductor element that houses the semiconductor integrated circuit element and the probe of the probe card that performs electrical inspection of the semiconductor integrated circuit is also required.

  In response to this demand for narrow pitches, in the package for housing semiconductor devices, the mounting form of the semiconductor devices is changed from wire bonding connection to flip chip connection, and the probe card is a cantilever type, and needle-like probes are finely latticed. It has changed to something arranged in a shape.

  In addition, the structure of the multilayer wiring board used in the semiconductor element storage package and the probe card is formed by forming a wiring conductor layer obtained by patterning a copper foil on an insulating layer obtained by impregnating and curing an organic resin on a substrate made of glass fiber. Multi-layer consisting of a thin insulating layer and a wiring conductor layer on the top surface of the substrate, which is excellent in narrowing the pitch of the wiring conductor layer and can be arranged in a fine lattice pattern. It is changing to a build-up type multilayer wiring board in which a wiring part is formed.

  Such a build-up type multilayer wiring board is made of an epoxy resin, a polyimide resin, or the like on the upper surface of the board, and is formed by applying a resin precursor by a curtain coating method, a spin coating method, or the like and then heat-curing the insulating layer. And a structure in which wiring conductor layers made of a metal such as copper or aluminum are alternately laminated in multiple layers by adopting a thin film formation technique such as a plating method or a vapor deposition method and a photolithography technique. It has become.

In addition, in these multilayer circuit boards of the build-up method, nickel is formed on the wiring conductor layer made of copper on the outermost surface in order to keep the connection with the terminal portion of the semiconductor element and the environmental resistance reliability in a good state. A protective plating film mainly made of metallurgy is formed.
JP-A-11-163520 Japanese Unexamined Patent Publication No. 11-38044

  However, in order to form a protective plating film, it is necessary to secure a path for conducting electricity in the case of electrolytic plating, and in the case of electroless plating, the resin material is eroded by the liquidity of the plating solution. In some cases, the plating solution that can be used is limited. Further, in the case of electroless plating, when the interval between adjacent wiring conductor layers is narrow, there is a problem that adjacent wiring conductor layers are easily short-circuited due to spreading of plating.

The present invention has been made in view of the problems in the background art as described above, and its object is to have a high degree of freedom in design, to form a desired protective plating film, and to narrow the wiring conductor layer. An object of the present invention is to provide a method of manufacturing a multilayer wiring board that can cope with pitching.

Method for manufacturing a multilayer wiring board of the present invention, on an insulating substrate, with a plurality of layers alternately laminating insulating layer consisting of wiring conductor layer and a resin, wherein between them the conductor layers to each other positioned vertically a step of electrically connecting via a through conductor formed on the insulating layer,
Forming a surface wiring conductor layer on the surface of the outermost insulating layer;
After pasting the resin protective layer on the metal substrate, forming a through hole in the resin protective layer;
Forming a metal protective layer 6 in the through hole by electrolytic plating using the metal substrate as an electrical conductor;
The resin protective layer 7 is laminated on the surface of the outermost insulating layer on the surface overlapping the surface wiring conductor layer with the exposed surface of the metal protective layer facing down, and the metal protective layer is bonded to the surface wiring conductor layer And a process of
It is characterized in Rukoto and a step of removing the metal substrate.

A method for manufacturing a multilayer wiring board of the present invention, in the step of laminating the resin protective layer on the surface of the insulating layer of the outermost layer, the surface wiring conductor layer, said metal protective layer via the conductive resin layer those characterized that you join the.

A method for manufacturing a multilayer wiring board of the present invention, in the step of laminating the resin protective layer on the surface of the insulating layer of the outermost layer, the surface wiring conductor layer, said metal protective layer through a number of fine metal particles those characterized that you join the.

According to the method for manufacturing a multilayer wiring board of the present invention, the surface of the outermost insulating layer, in a through hole formed in a portion that overlaps the surface wiring conductor layer to form a metal protective layer so as to close the through-hole resin and stacking a protective layer, because it was to join the metal protective layer on the surface wiring conductor layer, the bonding strength between the surface wiring conductor layer and the metal protection layer, the connection surfaces of the resin protective layer and the metal protection layer Therefore, the surface wiring conductor layer and the metal protective layer can be bonded more firmly.

  Further, compared to the formation of the metal protective layer by the electrolytic plating method, the electric conduction wiring necessary for the electrolytic plating is not required, and the multilayer wiring board can be further densified. Further, compared to the formation of the metal protective layer by the electroless plating method, adjacent wiring conductor layers are not short-circuited due to the spreading of the plating. Furthermore, in the electroless plating method, the plating formation time has to be shortened to prevent the spread of the plating, and the thickness of the plating layer is limited. As a result, a desired thickness can be obtained under free design conditions.

Thus, high design flexibility of the multilayer wiring board, a method of manufacturing the multilayer wiring board may correspond to the pitch of the wiring conductor layer it is possible to form a plating film for the desired protection.

Further, according to the method of manufacturing the multilayer wiring board of the present invention, in the step of laminating a resin protective layer on the surface of the outermost layer of the insulating layer, the surface wiring conductor layers, the metal protective layer via the conductive resin layer bonded If you like to also surface roughness of the surface to be respective connection surface wiring conductor layer and the metal protective layer is greatly, be firmly bonded by a conductive resin enters the unevenness of the surface Will be able to.

Further, according to the method of manufacturing the multilayer wiring board of the present invention, in the step of laminating a resin protective layer on the surface of the outermost layer of the insulating layer, the surface wiring conductor layers, the metal protective layer over the plurality of metal particles joined If you like to also each surface roughness of the connected surface of the surface wiring conductor layer and the metal protective layer is greatly, by metal particles from entering to fill the unevenness of the surface, more robust It becomes possible to join to. Further, the connection resistance can be reduced by using metal particles having low resistance.

By these, by holding without kicking greatly influenced the bonding strength between the surface wiring conductor layer and the metal protective layer on the surface roughness, high design flexibility of the multilayer wiring board, for the desired protection This is a method for manufacturing a multilayer wiring board that can form a plating film and can cope with a narrow pitch of the wiring conductor layer.

Hereinafter, a method for producing a multilayer wiring board according to the present invention will be described in detail with reference to the drawings.

FIG. 1 is a cross-sectional view showing an example of a multilayer wiring board manufactured by the method for manufacturing a multilayer wiring board according to the present invention, and FIGS. 2, 3 and 4 show the multilayer wiring board manufactured by the manufacturing method according to the present invention. It is a principal part expanded sectional view which shows the various examples of the periphery of the wiring conductor layer of the outermost surface. In these drawings, 1 is an insulating substrate, 2 is an insulating layer, 3 is a wiring conductor layer, 4 is a through conductor, 5 is a through hole, 6 is a metal protective layer, 7 is a resin protective layer, 8 is a conductive resin layer, 9 is a number of fine metal particles and 10 is a through hole.

  The insulating substrate 1 is provided with a multilayer wiring portion in which a plurality of wiring conductor layers 3 and insulating layers 2 made of resin are alternately laminated on the upper surface thereof, and functions as a support member that supports the multilayer wiring portion. .

  The insulating substrate 1 is made of an oxide ceramic such as an aluminum oxide sintered body or a mullite sintered body, or a non-oxide such as an aluminum nitride sintered body or silicon carbide sintered body having an oxide film on the surface. Further, it is made of an electrically insulating material such as a glass ceramic resin obtained by impregnating a glass fiber base material with an epoxy resin or a glass fiber base material impregnated with a bismaleimide triazine resin.

  For example, when it is formed of an aluminum oxide sintered body, a suitable organic solvent and solvent are added to and mixed with raw material powders such as alumina, silica, calcia, and magnesia to form a slurry, which is then treated by the doctor blade method. A ceramic green sheet (ceramic green sheet) is formed by adopting the calender roll method, and after that, the ceramic green sheet is punched appropriately to obtain a predetermined shape and fired at a high temperature (about 1600 ° C). It is manufactured by. Alternatively, a raw material powder is prepared by adding an appropriate organic solvent and solvent to a raw material powder such as alumina, and the raw material powder is formed into a predetermined shape by a press molding machine. Finally, the compact is heated to a high temperature (about 1600 ° C). ). Moreover, when it consists of glass epoxy resins, it manufactures, for example by impregnating the base material which consists of glass fiber with the precursor of an epoxy resin, and thermosetting this epoxy resin precursor at predetermined temperature.

  The insulating substrate 1 is provided with a multilayer wiring portion in which a plurality of wiring conductor layers 3 and insulating layers 2 made of resin are alternately laminated on the upper surface thereof. The insulating layer 2 constituting the multilayer wiring portion electrically insulates the wiring conductor layer 3 positioned above and below, and the wiring conductor layer 3 functions as a transmission path for transmitting an electric signal.

  The insulating layer 2 of the multilayer wiring portion is composed of, for example, an insulating film layer and an insulating adhesive layer, and the insulating film layer is made of polyimide resin, polyphenylene sulfide resin, wholly aromatic polyester resin, fluorine resin, or the like. The insulating adhesive layer is made of siloxane-modified polyamideimide resin, siloxane-modified polyimide resin, polyimide resin, bismaleimide triazine resin, or the like.

  The insulating layer 2 is prepared, for example, by first applying an insulating adhesive to an insulating film of about 12.5 to 50 μm to a dry thickness of about 5 to 20 μm using a doctor blade method or the like, and then drying the insulating film layer. Are stacked such that an insulating adhesive layer is disposed between the upper surfaces of the insulating substrate 1 and the lower insulating layer 2, and these are heated and pressed using a heating press device and bonded together.

  As a combination of the insulating film layer and the insulating adhesive layer used for these, for example, there is a combination in which the insulating film layer is a polyimide resin and the insulating adhesive layer is a siloxane-modified polyamideimide resin. According to this combination, the adhesion between the siloxane-modified polyamideimide resin and the polyimide resin is good and the heat resistance is high, so that the multi-layer wiring board formed by these is resistant to being mounted on a printed board or the like. Good solder heat resistance and the like.

  Further, as a combination having particularly high heat resistance, it is preferable to use an insulating film layer as a polyimide resin and an insulating adhesive layer as a thermoplastic polyimide resin. In the case of this combination, the heat resistance is high and the difference in linear expansion coefficient between the insulating film layer and the insulating adhesive layer can be reduced, so that the stress due to the difference in linear expansion coefficient can be reduced. By reducing the overall warpage of the multilayer wiring board, the multilayer wiring board can better cope with the narrow pitch of the terminals of the semiconductor integrated circuit elements mounted on the surface thereof. can do.

  Further, each insulating layer 2 is provided with a wiring conductor layer 3 and the wiring conductor layers 3 positioned above and below the insulating layer 2 are electrically connected to each other so as to penetrate through the insulating layer 2. A through conductor 4 is embedded in the hole 5. These wiring conductor layers 3 and through conductors 4 adopt thin film formation techniques such as sputtering, vapor deposition, plating, etc., of metal materials such as copper, gold, aluminum, nickel, chromium, molybdenum, titanium, and alloys thereof. Can be formed.

  The through conductors 4 may be formed separately from the wiring conductor layer 3, but it is preferable that these are formed at the same time in that the number of steps can be reduced, and also in terms of electrical connection reliability between the two. It will be good. In addition, when the wiring conductor layer 3 and the through conductor 4 are integrally formed, the wiring conductor layer 3 and the through conductor 4 are mainly formed by using an electrolytic plating method so that each can be adjusted to a desired thickness and formed by a plating film. It is good to keep.

  The wiring conductor layer 3 is preferably embedded in the insulating layer 2 as shown in FIGS. Thereby, the wiring conductor layer 3 can be firmly fixed to the insulating layer 2, and the wiring conductor layer 3 can be effectively prevented from peeling off from the insulating layer 2. Further, the protruding amount of the wiring conductor layer 3 protruding from the insulating layer 2 can be reduced, and the flatness of the surface of the multilayer wiring board can be increased.

  The wiring conductor layer 3 and the through conductor 4 are formed by, for example, forming a wiring pattern-shaped recess for the wiring conductor layer 3 so that the wiring conductor layer 3 is first embedded in the surface of the insulating layer 2. And a through hole 5 for the through conductor 4 is formed.

  The recess for the wiring conductor layer 3 is formed, for example, by removing a part on the upper surface side of the insulating layer 2 by performing oxygen plasma treatment on the upper surface side of the insulating layer 2 using a metal film as a mask. The through hole 5 is formed by removing the insulating layer 2 at a predetermined position of the recess for the wiring conductor layer 3 using, for example, a laser. In particular, when the diameter of the opening of the through hole 5 is small, it is desirable to control the angle of the inner wall surface of the through hole 5 and to form the inner wall surface of the through hole 5 with an ultraviolet laser or the like that is processed smoothly. .

  Next, an underlying conductor layer composed of a diffusion prevention layer (barrier layer) made of chromium, molybdenum, titanium or the like and a copper layer mainly made of copper deposited thereon on the entire upper surface of the insulating layer 2 Is formed by electroless plating or sputtering. Then, a resist pattern is formed on the substrate 1 on which the base conductor layer is formed so as to cover a portion other than the portion that becomes the wiring conductor layer 3 using a photolithography method, and then the wiring conductor layer 3 and the main conductor layer of the through conductor 4 are formed. The part is formed by electrolytic plating. Thereafter, the resist pattern is removed, and the excess underlying conductor layer covered with the resist pattern is removed by a chemical etching method, a dry etching method, or the like, thereby forming a wiring conductor layer 3 partially embedded in the insulating layer 2 Is done.

  Of the wiring conductor layer 3, the surface wiring conductor layer 3 ′ formed on the surface of the insulating layer 2 which is the outermost layer of the multilayer wiring board is made of a copper layer from the viewpoint of electrical characteristics and connection reliability. In this case, a nickel layer or a gold layer is preferably formed on the main conductor layer from the viewpoint of connection reliability and environmental resistance.

At this time, in the method for manufacturing a multilayer wiring board according to the present invention, a metal is formed so that the through-hole 10 is formed on the surface of the outermost insulating layer 2 so as to cover the through-hole 10 formed in a portion overlapping the surface wiring conductor layer 3 ′. and laminating a resin protective layer 7 forming the protective layer 6, so as to bond the metal protective layer 6 on the surface wiring conductor layer 3 '. As a result, the bonding strength between the surface wiring conductor layer 3 ′ and the metal protective layer 6 is supplemented by the bonding strength at the connection surface between the resin protective layer 7 and the metal protective layer 6. It becomes possible to join the layer 6 more firmly.

  Further, compared to the formation of the metal protective layer 6 by the electrolytic plating method, the electric conduction wiring necessary for the electrolytic plating is not required, and the multilayer wiring board can be further densified. Further, compared to the formation of the metal protective layer 6 by the electroless plating method, adjacent wiring conductor layers 3 are not short-circuited by spreading of the plating. Furthermore, in the electroless plating method, the plating formation time has to be shortened to prevent the spread of the plating, and the thickness of the plating layer is limited. 6, a desired thickness can be obtained under free design conditions.

  The resin protective layer 7 is made of, for example, polyimide resin, polyphenylene sulfide resin, wholly aromatic polyester resin, fluorine resin, siloxane-modified polyamideimide resin, siloxane-modified polyimide resin, polyimide resin, bismaleimide triazine resin, or the like.

  The metal protective layer 6 is made of, for example, copper, gold, aluminum, nickel, chromium, molybdenum, titanium, or an alloy thereof.

  In such a method of forming the resin protective layer 7 and the metal protective layer 6, first, the resin protective layer 7 is attached to a separately prepared metal substrate, and then the through hole 10 is formed at a desired site with a laser or the like. Next, the metal protective layer 6 is formed in the through hole 10 by electrolytic plating using the metal substrate as an electrical conductor. A resin protective layer 7 on which a metal protective layer 6 is formed so as to close the through hole 10 is laminated and bonded to a portion overlapping the surface wiring conductor layer 3 ′ with the exposed surface of the metal protective layer 6 as a lower surface. To do. Thereafter, the metal protective layer 6 can be formed on the surface wiring conductor layer 3 ′ by removing the metal substrate by etching.

  Further, when the position of the upper surface of the metal protective layer 6 joined to the surface wiring conductor layer 3 ′ is positioned below the upper surface of the resin protective layer 7 (the upper surface of the metal protective layer 6 is positioned in the through hole 10. In the case of performing the above, a through hole 10 is formed at a desired portion of the resin protective layer 7 on the metal substrate with a laser or the like, and then a metal layer of the same type as the metal substrate is formed on the metal substrate side in the through hole 10. In addition, the metal protective layer 6 is formed thereon. As a result, when the metal substrate is etched, the same kind of metal layer as that of the metal substrate is simultaneously etched so that the upper surface of the metal protective layer 6 is positioned in the through hole 10.

  At this time, in the present invention, if a bonding material is disposed at the interface between the surface wiring conductor layer 3 ′ and the metal protective layer 6, the bonding strength between the surface wiring conductor layer 3 ′ and the metal protective layer 6 is improved. Can do. For example, the bonding material includes a conductive resin layer 8 and a large number of metal fine particles 9. These bonding materials penetrate into the irregularities on the surfaces of the surface wiring conductor layer 3 ′ and the metal protective layer 6, so that the surface wiring conductor layer 3 ′ and the metal protective layer 6 can be firmly bonded.

  In particular, if the diameter of the large number of metal fine particles 9 is set to 100 nm or less, the bonding temperature can be lowered, and the thermal influence on the insulating substrate 1 and the multilayer wiring portion can be lowered. Thus, a good connection state can be obtained without degrading the performance. For this reason, the diameter of the large number of metal fine particles 9 is preferably 100 nm or less.

Thus, according to the multilayer wiring board manufactured by the manufacturing method of the multilayer wiring board of the present invention, the semiconductor is formed on the metal protective layer 6 bonded on the surface wiring conductor layer 3 ′ formed on the surface of the outermost insulating layer 2. A semiconductor device is obtained by mounting an integrated circuit and electrically connecting the multilayer wiring board to an external electric circuit.

Moreover, according to the multilayer wiring board manufactured by the method for manufacturing a multilayer wiring board of the present invention, the multilayer protective circuit board is brought into contact with the metal protective layer 6 bonded on the surface wiring conductor layer 3 ′ formed on the surface of the outermost insulating layer 2. Thus, a probe card for electrical inspection of a semiconductor integrated circuit or the like is obtained by arranging and fixing the probe and electrically and mechanically connecting the multilayer wiring board to an external electric circuit.

  It should be noted that the present invention is not limited to the above embodiments, and various modifications can be made without departing from the scope of the present invention. For example, in the above-described example, the metal protective layer 6 is bonded onto the surface wiring conductor layer 3 ′, but the metal protective layer 6 is formed on both the surface wiring conductor layer 3 ′ and the outermost insulating layer 2. You may make it join.

It is sectional drawing which shows an example of the multilayer wiring board manufactured by the manufacturing method of the multilayer wiring board of this invention. It is a principal part expanded sectional view which shows the surrounding state of the metal protective layer in the multilayer wiring board of FIG. It is a principal part expanded sectional view which shows the example of the periphery of the metal protective layer in the multilayer wiring board manufactured by the other example of the manufacturing method of the multilayer wiring board of this invention. It is a principal part expanded sectional view which shows the example of the periphery of the metal protective layer in the multilayer wiring board manufactured by the other example of the manufacturing method of the multilayer wiring board of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Insulating substrate 2 ... Insulating layer 3 ... Wiring conductor layer 3 '... Surface wiring conductor layer 4 ... Through conductor 5 ... Through hole 6 ...・ Metal protective layer 7 ... Resin protective layer 8 ... Conductive resin layer 9 ... Metal fine particles
10 ... Through hole

Claims (3)

On an insulating substrate, with a plurality of layers alternately laminating insulating layer consisting of wiring conductor layer and a resin, the electrical said wiring conductor layers to each other positioned vertically through the through conductor said formed in an insulating layer between them Connecting to each other ,
Forming a surface wiring conductor layer on the surface of the outermost insulating layer;
After pasting the resin protective layer on the metal substrate, forming a through hole in the resin protective layer;
Forming a metal protective layer in the through hole by electrolytic plating using the metal base as an electrical conductor;
The resin protective layer is laminated on the surface of the outermost insulating layer, with the exposed surface of the metal protective layer facing down, and laminated on the surface wiring conductor layer, and the metal protective layer is bonded to the surface wiring conductor layer Process,
Method for manufacturing a multilayer wiring board, wherein Rukoto and a step of removing the metal substrate. In the step of laminating the resin protective layer on the surface of the insulating layer of the outermost layer, the surface wiring conductor layer, according to claim 1, wherein through the conductive resin layer, characterized that you joining said metal protective layer Manufacturing method of multilayer wiring board. In the step of laminating the resin protective layer on the surface of the insulating layer of the outermost layer, the surface wiring conductor layer, according to claim 1, characterized that you joining said metal protective layer through a number of fine metal particles Manufacturing method of multilayer wiring board.

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