JP4578254B2 - Multilayer wiring board - Google Patents

Description

  The present invention relates to a multilayer wiring board, and more particularly, to a multilayer wiring board used for a semiconductor element housing package for housing a semiconductor integrated circuit element, a probe card for electrically inspecting a semiconductor integrated circuit, and the like. Is.

  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 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. Multilayer consisting of a resin insulating layer and a thin wiring conductor layer on the upper surface of the substrate, which is excellent in narrowing the pitch of the wiring conductor layer and capable of arranging the wiring conductor layer in a fine lattice pattern It is changing to a build-up type multilayer wiring board in which a wiring part is formed.

As shown in FIG. 4, 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 wiring board 11, and a resin precursor is applied by a curtain coating method or a spin coating method and heated. A resin insulating layer 14 formed by curing, and a wiring conductor layer made of a metal such as copper or aluminum, and formed by adopting a thin film forming technique such as a plating method or a vapor phase film forming technique and a photolithography technique 15 is laminated.
JP 11-163520 A Japanese Patent Laid-Open No. 11-38044

  However, the conventional build-up type multilayer wiring board is formed by laminating a copper foil on the main surface of an insulating base 12 in which a glass cloth is impregnated with a resin, and etching the copper foil into a wiring pattern to form a conductor layer 13. Since the wiring substrate 11 is formed by forming the conductive layer 13 made of the metallized layer on the main surface of the insulating base 12 made of ceramics, the surface of the wiring substrate 11 protrudes from the conductive layer 13. It became an uneven shape. When the resin insulating layer 14 is laminated on the upper surface of the wiring substrate 11, the upper surface of the resin insulating layer 14 is also uneven according to the uneven shape of the surface of the wiring substrate 11. When the number of the resin insulation layers 14 is further increased, the uneven shape on the surface of the uppermost resin insulation layer 14 becomes larger, resulting in variations in the height of the surface of the wiring conductor layer 15 formed on the surface. As a probe card or a package for housing a semiconductor element, the length of the connection member for electrical connection between the wiring conductor layer 15 and the semiconductor element changes, and the electrical characteristics such as electrical resistance deteriorate, and the connection member Due to the difference in length, there is a problem in that stress is biased and concentrated on the connection portion of the connection member, resulting in poor electrical conduction such as breakage of the connection portion.

  The present invention has been made in view of the problems in the background art as described above, and an object of the present invention is to provide a multilayer wiring board having good surface flatness and excellent electrical characteristics and conduction reliability. There is.

In the multilayer wiring board of the present invention, a resin insulating layer and a wiring conductor layer are alternately laminated on a wiring board having a conductor layer on the upper surface, and the wiring conductor layer and the conductor layer positioned above and below are laminated on them. In a multilayer wiring board formed by electrically connecting through through conductors formed in the resin insulation layer, the wiring board comprises an insulating base and a resin coating layer having a through hole directly adhered to the upper surface thereof And the conductor layer provided so as to fill the through-hole, and the conductor layer is thermally expanded more than the main conductor portion covering the main conductor portion and the entire side surface and bottom surface continuously. A base conductor portion having a small coefficient, and the bottom conductor portion has a lower surface embedded inside the upper surface of the insulating base, an interface between the resin insulating layer and the insulating base, and the base Same interface between conductor and insulating substrate It is characterized in that the offset from the surface.

  The multilayer wiring board of the present invention is characterized in that, in the above configuration, the base conductor portion is thicker at a lower surface side of the conductor layer than at a side surface of the conductor layer.

According to the multilayer wiring board of the present invention, the wiring board is composed of an insulating base, a resin coating layer having a through hole that is in direct contact with the upper surface thereof, and a conductor layer provided so as to fill the through hole. Since the conductor layer is composed of the main conductor portion and the base conductor portion having a smaller coefficient of thermal expansion than the main conductor portion that continuously covers the entire side surface and bottom surface, the resin insulating layer and the insulating base Since there is no conductor layer between them, unevenness generated on the surface of the resin insulating layer due to the thickness of the conductor layer is eliminated, and the flatness of the surface of the multilayer wiring board can be greatly enhanced.

In addition, the conductor layer is composed of a main conductor portion and a base conductor portion having a lower coefficient of thermal expansion than the main conductor portion that continuously covers the entire side surface and bottom surface of the main conductor portion. Restraining by the conductor portion can suppress the thermal expansion of the entire conductor layer. Therefore, even if there are contacts of three kinds of materials, that is, an insulating base, a conductor layer, and a resin insulating layer having different thermal expansion coefficients, stress generated at the contacts can be effectively suppressed. The conduction reliability can be made extremely high.

  Further, according to the multilayer wiring board of the present invention, since the lower conductor side portion of the conductor layer is thicker than the side portion of the conductor layer, the resin insulating layer is laminated in multiple layers and each resin insulation Even in the case of a so-called stack structure in which the through conductors formed in the layer are stacked directly on the conductor layer, the stress generated at the interface between the conductor layer and the insulating substrate can be more effectively suppressed. In other words, in the case of a stack structure, the conductor layer is not only subjected to stress due to the thermal expansion of the entire through conductor that overlapped in the vertical direction, but also in contact with the insulating substrate having a different thermal expansion coefficient. Although stress is particularly concentrated at the interface with the base, the stress can be more effectively suppressed by increasing the thickness of the underlying conductor portion against this stress.

  Further, according to the multilayer wiring board of the present invention, since the lower surface of the base conductor is embedded inside the upper surface of the insulating base, the interface between the resin insulating layer and the insulating base, and the base conductor And the insulation substrate can be shifted from the same plane, effectively preventing the stresses generated at those interfaces from being combined due to thermal expansion to become a large stress and improving the connection reliability between the through conductor and the conductor layer. It can be improved further.

  Hereinafter, a multilayer wiring board of the present invention will be described in detail with reference to the drawings.

  FIG. 1 is a cross-sectional view showing an example of an embodiment of a multilayer wiring board of the present invention, and FIG. 2 is an enlarged cross-sectional view of a main part showing a state around a conductor layer 3 in the multilayer wiring board shown in FIG. FIG. 3 is an enlarged cross-sectional view of the main part showing the state of the periphery of the conductor layer 3 in another example of the embodiment of the multilayer wiring board of the present invention. In these drawings, 1 is a wiring board, 2 is an insulating substrate, 3 is a conductor layer, 4 is a resin insulating layer, 5 is a wiring conductor layer, 6 is a through conductor, 7 is a main conductor portion, 8 is a base conductor portion, 9 Are through-holes and 10 is a resin coating layer.

  The wiring substrate 1 is configured by directly attaching a resin coating layer 10 having a through hole 9 to the upper surface of the insulating base 2 and providing the conductor layer 3 so as to fill the through hole 9. A thin film wiring portion in which the resin insulating layer 4 and the wiring conductor layer 5 are laminated is disposed on the upper surface of the wiring substrate 1 and functions as a support member that supports the thin film wiring portion.

  The insulating substrate 2 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. It is made of an electrically insulating material such as epoxy resin reinforced with ceramics or glass cloth.

  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 a calender roll method, and then, the ceramic green sheet is appropriately punched 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 and mixing 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. ).

  The resin coating layer 10 is made of various insulating resins. For example, a siloxane-modified polyamideimide resin, a main surface of an insulating film 10a made of polyimide resin, polyphenylene sulfide resin, wholly aromatic polyester resin, fluorine resin, or the like, What formed the insulating adhesive bond layer 10b which consists of a siloxane modified polyimide resin, a polyimide resin, a bismaleimide triazine resin etc. is used.

  The resin insulating layer 4 may be made of a material different from that of the resin coating layer 10 or the same material. Preferably, the material is the same as that of the resin coating layer 10 in order to reduce the difference in thermal expansion coefficient. Such a resin insulating layer 4 is formed on the main surface of an insulating film 4a made of, for example, polyimide resin, polyphenylene sulfide resin, wholly aromatic polyester resin, fluororesin, or the like. In this case, an insulating adhesive layer 4b made of bismaleimide triazine resin or the like is used.

  The resin coating layer 10 and the resin insulating layer 4 are prepared, for example, by first applying an insulating adhesive to an insulating film of about 5 to 20 μm to a dry thickness of about 5 to 10 μm using a doctor blade method or the like. Then, this is formed by heating and pressing the insulating substrate 2 or the resin coating layer 10 on the insulating substrate 2 or the resin coating layer 10 using a heating press.

  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.

  Moreover, when the insulating film layer is made of polyimide resin and the insulating adhesive layer is made of siloxane-modified polyimide resin, the heat resistance is high, and even if the insulating substrate 2 is made of ceramic, it is formed by this combination. Since the difference in thermal expansion coefficient among the resin coating layer 10, the resin insulating layer 4, and the insulating substrate 2 can be reduced, the stress due to the difference in thermal expansion coefficient can be reduced. Therefore, it becomes possible to reduce the overall warpage of the multilayer wiring board, so that the multilayer wiring that can better cope with the narrow pitch of the terminals of the semiconductor integrated circuit element mounted on the surface thereof. It can be a substrate.

  Further, the through hole 9 of the resin coating layer 10 is filled with the conductor layer 3. The conductor layer 3 includes a main conductor portion 7 and a base conductor portion 8 having a smaller coefficient of thermal expansion than the main conductor portion 7 that continuously covers the side and bottom surfaces of the main conductor portion 7.

  The main conductor portion 7 is made of a low electrical resistance metal such as copper, gold, or aluminum. The base conductor portion 8 is made of a metal having a smaller thermal expansion coefficient than the main conductor portion 7, and is made of a metal material such as nickel, chromium, molybdenum, tungsten, tantalum, ruthenium, titanium, and alloys thereof. By using such a metal material, the underlying conductor portion 8 also has a function as a diffusion prevention layer (barrier layer) and an adhesive layer for the main conductor portion 7.

  Preferably, the thermal expansion coefficient of the base conductor portion 8 is 0.2 to 0.9 times the thermal expansion coefficient of the main conductor portion 7. When it exceeds 0.9 times, the effect of restraining the thermal expansion of the entire conductor layer 3 by restraining the thermal expansion of the main conductor portion 7 with the base conductor portion 8 tends to be small. On the other hand, when the ratio is less than 0.2 times, the difference in thermal expansion coefficient between the main conductor portion 7 and the underlying conductor portion 8 becomes large, and stress is generated at these interfaces, and the conduction reliability of the conductor layer 3 is likely to be lowered.

  In the conductor layer 3, first, the resin coating layer 10 is laminated on the insulating base 2, and the pattern-shaped through-hole 9 of the conductor layer 3 is formed in the resin insulating layer 4. Such a through-hole 9 is formed by, for example, performing oxygen plasma treatment on the upper surface side of the resin insulating layer 4 using a metal film as a mask, or by partially removing the upper surface side of the resin insulating layer 4 by using a laser. It is formed.

  Next, by adopting a thin film forming technique such as sputtering, vapor deposition or plating on the entire upper surface of the resin insulating layer 4, the inner surface of the through hole 9, and the surface of the insulating base 2 exposed in the through hole 9, The base conductor portion 8 is deposited. After that, next, the main conductor portion 7 is formed on the entire upper surface of the underlying conductor portion 8 until the through hole 9 is filled by electrolytic plating or the like. Thereafter, the electroplated film formed to an unnecessary thickness is removed to a predetermined thickness by a polishing method, a chemical etching method, or the like, whereby the conductor layer 3 having a desired pattern shape can be processed.

  Preferably, the base conductor portion 8 has a portion on the lower surface side of the conductor layer 3 that is thicker than a portion on the side surface side of the conductor layer 3. As a result, even when the resin insulating layer 4 is laminated in multiple layers and the through conductor 6 formed in each resin insulating layer 4 is stacked directly on the conductor layer 3, a so-called stack structure is formed. 2 can be more effectively suppressed. That is, in the case of the stack structure, the conductor layer 3 is not only subjected to stress due to the thermal expansion of the entire through conductor 6 overlapped in the vertical direction, but is also in contact with the insulating base 2 having different thermal expansion coefficients. Although stress is particularly concentrated at the interface between the layer 3 and the insulating substrate 2, the stress can be more effectively suppressed by increasing the thickness of the underlying conductor portion 8 against this stress.

  In particular, the base conductor portion 8 formed on the side surface side of the conductor layer 3 has a thickness of 0.01 μm or more and 0.3 μm or less in order to eliminate the influence of the internal stress of the metal film on the resin insulating layer 4. The base conductor portion 8 formed on the lower surface side is preferably 0.5 μm or more and 3 μm or less in thickness so that the thermal expansion difference with the insulating base 2 can be sufficiently relaxed.

The lower ground conductor portion 8, as shown in FIG. 3, a lower surface that are embedded in the inside than the upper surface of the insulating substrate 2. As a result, the interface between the resin insulating layer 4 and the insulating base 2 and the interface between the base conductor 8 and the insulating base 2 can be shifted from the same plane, and the stress generated at those interfaces due to thermal expansion is combined and large. It is possible to effectively prevent stress and to further improve the connection reliability between the through conductor 6 and the conductor layer 3.

  In addition, the resin insulating layers 4 and the wiring conductor layers 5 are alternately laminated on the upper surface of the wiring board 1, and the wiring conductor layers 5 and the conductor layers 3 positioned above and below are disposed between them. They are electrically connected through a through conductor 6 formed in the line 4. The wiring conductor layer 5 and the through conductor 6 are made of a low electrical resistance metal such as copper, gold, or aluminum, and can be formed by a thin film forming technique such as sputtering, vapor deposition, or plating.

  The wiring conductor layer 5 formed on the surface of the resin insulating layer 4 which is the uppermost layer of the multilayer wiring board is formed with a nickel layer or a gold layer on the exposed surface from the viewpoint of connection reliability and environmental reliability. Good.

  Thus, the semiconductor integrated circuit is mounted on the wiring conductor layer 5 formed on the surface of the resin insulating layer 4 positioned at the uppermost layer of the multilayer wiring board of the present invention, and the multilayer wiring board is electrically connected to the external electric circuit. As a result, a semiconductor device is obtained.

  In addition, the probe is placed and fixed in contact with the wiring conductor layer 5 formed on the surface of the resin insulating layer 4 positioned at the uppermost layer of the multilayer wiring board of the present invention, and the multilayer wiring board is electrically connected to an external electric circuit. And by connecting mechanically, it becomes a probe card for carrying out the electrical test | inspection of a semiconductor integrated circuit etc.

  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 resin insulating layer 4 has a two-layer structure of an insulating film layer and an insulating adhesive layer, but for example, an insulating adhesive layer is formed vertically around the insulating film layer. A laminate obtained by laminating or a liquid resin coated and heated and cross-linked may be used. Further, a plurality of resin insulating layers 4 and wiring conductor layers 5 may be formed.

It is sectional drawing which shows an example of embodiment of the multilayer wiring board of this invention. FIG. 2 is an enlarged cross-sectional view of a main part showing a state around a conductor layer in the multilayer wiring board of FIG. 1. It is a principal part expanded sectional view which shows the state of the periphery of the conductor layer in the other example of embodiment of the multilayer wiring board of this invention. It is sectional drawing of the conventional multilayer wiring board.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Wiring board 2 ... Insulating base 3 ... Conductor layer 4 ... Resin insulating layer 5 ... Wiring conductor layer 6 ... Penetration conductor 7 ... Lead Body part 8 ... Underly conductor part 9 ... Through hole 10 ... Resin coating layer

Claims (2)

A resin insulating layer and a wiring conductor layer are alternately laminated on a wiring board having a conductor layer on the upper surface, and the wiring conductor layer and the conductor layer positioned above and below are formed in the resin insulating layer therebetween. In the multilayer wiring board formed by electrical connection through the penetrating conductor, the wiring board is filled with the insulating base, a resin coating layer having a through hole in close contact with the upper surface thereof, and the through hole filled. The conductor layer is provided, and the conductor layer is composed of a main conductor portion and a base conductor portion having a smaller coefficient of thermal expansion than the main conductor portion that continuously covers the entire side surface and bottom surface of the main conductor portion. And the lower surface of the base conductor portion is embedded inside the upper surface of the insulating base, the interface between the resin insulating layer and the insulating base, and the base conductor and the insulating base. that shifted from an interface on the same plane Multilayer wiring substrate having a butterfly.   2. The multilayer wiring board according to claim 1, wherein the base conductor portion is thicker at a lower surface side of the conductor layer than at a side surface of the conductor layer.

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