JP5383448B2 - Wiring board, probe card and electronic device - Google Patents

Description

  The present invention relates to a wiring board used for a probe card or a wiring board for mounting electronic components such as a semiconductor element and a piezoelectric vibrator, and a probe card and an electronic apparatus using such a wiring board.

  In recent years, along with miniaturization and higher density of electronic devices, not only semiconductor elements used in electronic devices but also packages, wiring boards on which the semiconductor elements are mounted, or electrical inspection of semiconductor elements The probe card is also required to have finer wiring and higher density. In addition, it is required that a high-frequency signal can be transmitted with an increase in the speed of the semiconductor element, and the probe card is also required to have excellent flatness.

  In order to meet such demands, fine patterning is possible, and as a substrate excellent in flatness and high frequency characteristics, a thin film conductor and a thin insulating layer are formed on a ceramic substrate flattened by polishing. There is a so-called build-up type wiring board in which the formed multilayer wiring portion is formed (see, for example, Patent Document 1). FIG. 4 is a cross-sectional view showing an example of a conventional wiring board. A conventional wiring board is formed by alternately laminating insulating resin layers 12 and wiring layers 13 on the upper surface of a ceramic wiring board 11 composed of a plurality of ceramic insulating layers 18, internal wirings 15 and external wirings 17. . The wiring layers 13 positioned above and below the insulating resin layer 12, and the wiring layer 13 on the upper surface of the lowermost insulating resin layer 12 and the connection wiring 16 on the upper surface of the ceramic wiring substrate 11 are connected by the via conductors 14. It was what was.

Japanese Patent Laid-Open No. 2004-214586

  However, the conventional wiring board has a thermal expansion coefficient of the insulating resin layer 12 at the connection portion between the via conductor 14 formed in the lowermost insulating resin layer 12 and the connection wiring 16 formed on the upper surface of the ceramic wiring board 11. And thermal stress due to the difference between the thermal expansion coefficients of the ceramic wiring substrate 11 were easily applied. This is because the connection wiring 16 on the upper surface of the ceramic wiring board 11 is thin, and the bonding strength between the ceramic wiring board 11 and the ceramic insulating layer 18 is higher than that of the insulating resin layer 12. Because the behavior shows behavior according to the behavior of the ceramic wiring board 11 (ceramic insulating layer 18), and the via conductor 14 is formed in the insulating resin layer 12, it shows behavior according to the behavior of the insulating resin layer 12. The position of the bonding interface between the via conductor 14 formed in the lowermost insulating resin layer 12 and the connection wiring 16 formed on the upper surface of the ceramic wiring board 11 is between the ceramic wiring board 11 and the insulating resin layer 12. This is because it substantially coincides with the position where the thermal stress increases.

  With respect to such a conventional wiring board, further miniaturization of the wiring layer 13 is required, and the connection portion between the via conductor 14 and the connection wiring 16 on the upper surface of the ceramic wiring board 11 has a diameter of, for example, about 50 μm or less. If it is small, the connection strength between the via conductor 14 and the connection wiring 16 formed on the upper surface of the ceramic wiring substrate 11 decreases. In addition, the electrical inspection of semiconductor elements is performed simultaneously with a probe card on a large number of semiconductor elements on the wafer. However, if the size of the wafer increases to reduce the cost of the semiconductor elements, the probe card must also be enlarged. When the wiring board for the probe card becomes large, the thermal stress applied to the connection portion with the connection wiring 16 on the upper surface of the ceramic wiring board 11 of the via conductor 14 becomes large. Therefore, there has been a problem that it is easy to break between the via conductor 14 of the lowermost insulating resin layer 12 and the connection wiring 16 on the upper surface of the ceramic wiring substrate 11.

  The present invention has been made in order to solve the above-mentioned problems, and its purpose is to further reduce the possibility of the wiring breaking even if a thermal stress is generated between the insulating resin layer and the ceramic wiring board. Another object of the present invention is to provide a highly reliable wiring board suitable for use as a probe card.

In the wiring board of the present invention, a plurality of insulating resin layers and a plurality of wiring layers are alternately laminated on the upper surface of the ceramic wiring board, and the wiring layers positioned above and below the insulating resin layer are connected by via conductors. A wiring board in which the plurality of via conductors formed in the lowermost insulating resin layer and the ends of the plurality of internal wirings led out from the inside of the ceramic wiring board are electrically connected Each of the plurality of connection portions between the plurality of via conductors and the end portions of the plurality of internal wirings is provided from the upper surface of the ceramic wiring board to the side surface of the via conductor, and the insulating resin layer It is covered with a fixing material having a Young's modulus larger than that of the insulating resin, and the plurality of fixing materials are independent of each other .

  The wiring board of the present invention is characterized in that, in the above configuration, the fixing material is an insulating material.

  A probe card according to the present invention includes the wiring board according to the present invention having the above-described configuration, and probe pins connected to the wiring layer on the upper surface of the uppermost insulating resin layer.

  An electronic device according to the present invention includes the wiring board according to the present invention having the above-described configuration and an electronic component connected to the wiring layer on the upper surface of the uppermost insulating resin layer.

  According to the wiring board of the present invention, since the periphery of the connection portion between the via conductor and the end portion of the internal wiring is covered with the fixing material having a Young's modulus larger than the insulating resin of the insulating resin layer, Since the connection portion of the via conductor formed in the resin layer is fixed by a fixing material and is not easily deformed, the thermal stress applied to the connection portion between the via conductor and the end portion of the internal wiring is reduced, and there is a possibility of disconnection. A reduced and highly reliable wiring board is obtained.

  According to the wiring board of the present invention, in the above configuration, when the fixing material is an insulating material, the fixing material connected to the connection conductor and the via conductor is not conductive. Since it does not short-circuit even if it is small, it is possible to provide a wiring board with reduced possibility of disconnection at the connection portion between the via conductor and the end of the internal wiring without reducing the wiring density of the wiring board. .

  According to the probe card of the present invention, since the wiring board of the present invention having the above-described configuration and the probe pin connected to the wiring layer on the upper surface of the uppermost insulating resin layer are provided, a large-sized wafer corresponding to a large-sized wafer is provided. Even if it is a thing, it becomes a highly reliable probe card by which possibility that a wiring will fracture | rupture by a temperature change was reduced.

  According to the electronic device of the present invention, since the wiring board of the present invention having the above configuration and the electronic component connected to the wiring layer on the upper surface of the uppermost insulating resin layer are provided, the wiring breaks due to a temperature change. Therefore, a smaller and more reliable electronic device on which a smaller electronic component such as a semiconductor element with fine wiring is mounted is obtained.

(A) is a longitudinal cross-sectional view which shows an example of embodiment of the wiring board of this invention, (b) is a cross-sectional view in the AA of (a). (A) is sectional drawing which expands and shows the A section in FIG. 1, (b) and (c) are sectional drawings which expand and show the principal part of the other example of the wiring board of this invention, respectively. is there. It is sectional drawing which expands and shows the principal part of the other example of the wiring board of this invention. It is sectional drawing which shows an example of the conventional wiring board.

  A wiring board of the present invention and a probe card and an electronic device using the same will be described in detail with reference to the accompanying drawings. The example shown in FIG. 1 shows a simplified example in which the wiring layer 3 on the outermost surface of the wiring board is 16 pieces, the insulating resin layer 2 is 3 layers, and the ceramic insulating layer 8 of the ceramic wiring board 1 is also 3 layers. . Depending on the number of terminals of electronic components mounted on the wiring board, the number of semiconductor elements on the wafer to be inspected by the probe card, the number of terminals of the semiconductor elements, and their arrangement, the insulating resin layer 2, the wiring layer 3, The size and arrangement of the via conductor 4, the internal wiring 5 and the external wiring 7 are set.

  In the example shown in FIGS. 1 to 3, the via conductor 4 formed in the lowermost insulating resin layer 2 and the end of the internal wiring 5 are connected via a connection wiring 6. The ceramic wiring substrate 1 in which the internal wiring 5 and the ceramic insulating layer 8 are formed by simultaneous firing causes dimensional variations due to sintering shrinkage variations in the manufacturing process, so that the internal wiring exposed on the ceramic wiring substrate 1 is exposed. Similarly, the position 5 also varies. In order to absorb this variation and to ensure the connection between the via conductor 4 and the internal wiring 5, it is preferable to connect via the connection wiring 6. If the via conductor 4 of the lowermost insulating resin layer 2 is formed in conformity with the internal wiring 5 having a variation in position, the via conductor 4 and the end of the internal wiring 5 are not connected via the connection wiring 6. You may connect directly. In this case, the shape of the wiring layer 3 on the upper surface of the lowermost insulating resin layer 2 is made to be a shape corresponding to the positional variation of the internal wiring 5 of the ceramic wiring substrate 1 or large so as to absorb the positional variation. It is necessary to provide the connection wiring 6 because there is a possibility that productivity may be reduced and it may be difficult to route fine wiring.

  The ceramic wiring board 1 has an insulating base made of ceramics, an external wiring 7 formed on the surface thereof, and an internal wiring 5 formed inside. As shown in the example shown in FIG. 1, the insulating base is composed of a plurality of ceramic insulating layers 8 and the internal wiring 5 is developed, whereby the interval between the external wirings 7 on the lower surface of the ceramic wiring substrate 1 can be increased. When the interval between the wiring layers 3 on the upper surface of the insulating resin layer 2 is large, it is not necessary to develop the internal wiring 5, so the ceramic insulating layer 8 may be composed of one layer. When the ceramic insulating layer 8 is a single layer, the internal wiring 5 can be formed on the insulating base after the insulating base is manufactured. Therefore, the positional accuracy of the internal wiring 5 is high, and the connection wiring 6 can be made small. Can be omitted.

  The external wiring 7 on the lower surface of the ceramic wiring board 1 is for connecting the wiring board to an external circuit. The internal wiring 5 is for electrically connecting the external wiring 7 on the lower surface of the ceramic wiring substrate 1 to the wiring layer 3 formed on the insulating resin layer 2 and the like. There are a wiring layer and an internal through conductor that passes through the ceramic insulating layer 8 and connects the internal wiring layer and the internal wiring layer and the external wiring 7. In the example shown in FIGS. 1 to 3, the end portion of the internal wiring 5 to which the via conductor 4 formed in the lowermost insulating resin layer 2 is electrically connected is formed in the uppermost ceramic insulating layer 8. It becomes the upper end of the inner through conductor.

The ceramic insulating layer 8 of the ceramic wiring board 1 includes an aluminum oxide (alumina: Al ₂ O ₃ ) sintered body, an aluminum nitride (AlN) sintered body, a silicon carbide (SiC) sintered body, and a mullite sintered body. Body, made of ceramics such as glass ceramics. When used for a probe card, an aluminum oxide (Al ₂ O ₃ ) sintered material or glass ceramics having a thermal expansion coefficient close to that of silicon (Si) forming a wafer is preferable. When the ceramic insulating layer 8 is made of such ceramics, when the probe terminal is formed on the wiring board, the wafer and the wiring board joined together with the probe terminal, which are added to the probe terminal and the joint portion of the probe terminal, This is preferable because the thermal stress due to the difference in thermal expansion is relatively small. Further, when used as a probe card, it is possible to effectively prevent thermal deformation with respect to a thermal load during measurement of electrical characteristics of a semiconductor element, and furthermore, heat is not retained inside due to high heat transferability.

  The internal wiring 5 and the external wiring 7 of the ceramic wiring substrate 1 are formed by simultaneous firing with the ceramic insulating layer 8, tungsten (W), molybdenum (Mo), molybdenum-manganese (Mo—Mn) alloy, silver (Ag) , Copper (Cu), gold (Au), silver-palladium (Pd) alloy, etc.

  Such a ceramic wiring substrate 1 is manufactured by the following method. For example, when the ceramic insulating layer 8 is formed of an aluminum oxide sintered body, first, an appropriate organic binder and solvent are added to and mixed with raw material powders of aluminum oxide, silicon oxide, magnesium oxide and calcium oxide, and the slurry is mixed. This is formed into a sheet shape by a doctor blade method or the like to produce a plurality of ceramic green sheets to be the ceramic insulating layer 8.

  Next, through holes are formed by punching or laser processing using a mold or the like at a predetermined position where the internal through conductors of the ceramic green sheet are formed, and the through holes are filled with a conductive paste. Further, a conductive paste layer to be the internal wiring layer or the external wiring 7 is formed to a thickness of 10 to 20 μm at a predetermined position of the ceramic green sheet by a screen printing method or the like. The conductive paste is produced by kneading a metal powder having a high melting point such as tungsten (W), molybdenum (Mo), molybdenum-manganese (Mo-Mn) alloy, an appropriate resin binder, and a solvent.

  Finally, these ceramic green sheets are superposed and pressure-bonded to produce a laminate, and the laminate is fired at a high temperature of about 1500 ° C. to 1600 ° C., thereby producing the ceramic wiring substrate 1. A nickel plating layer with a thickness of about 1 to 10 μm and a gold plating layer with a thickness of about 0.1 to 3 μm are sequentially formed on the surface of the external wiring 7 of the ceramic wiring board 1 in order to prevent corrosion and connect with external circuits. Good. A similar plating layer may be formed on a portion of the internal wiring 5 exposed on the upper surface of the ceramic wiring substrate 1 (an end portion of the internal wiring 5).

  If the ceramic insulating layer 8 is made of glass ceramics, when the ceramic green sheet is sintered at a temperature at which the ceramic green sheet is sintered, the constrained green sheet mainly composed of alumina or the like is laminated on both sides of the laminate and fired. The constrained green sheet is preferable because the ceramic green sheet suppresses the sintering shrinkage in the direction of the laminated surface, and the ceramic wiring substrate 1 having a small shrinkage in the plane direction and good shrinkage variation and good dimensional accuracy can be obtained.

  When the ceramic insulating layer 8 is a single layer, first, a ceramic green sheet is laminated to produce a laminated body having a predetermined thickness, or a raw material powder added with an appropriate organic binder is die pressed. Then, a molded body is prepared and fired to produce an insulating substrate. Next, a through hole for forming the internal wiring 5 (internal through conductor) is formed in the insulating substrate by blasting or laser processing. The blasting is performed by placing a mask made of, for example, a resist film or the like having an opening in a portion where the through hole is formed on the upper surface of the insulating substrate. If at least the upper surface of the insulating substrate is polished flatly by polishing before or after the formation of the through-hole, the flatness of the wiring substrate can be improved and the insulating resin layer 2 can be satisfactorily formed. preferable. An insulating substrate having a through-hole is formed by punching or laser processing a ceramic green sheet or a laminate of ceramic green sheets, or by forming a through-hole with a mold during powder press molding. Can also be produced. In this case, since the positional displacement of the through hole for forming the internal wiring 5 due to firing shrinkage occurs, it is more preferable to form the through hole after the insulating base is manufactured as described above. Then, the conductive paste to be the internal wiring 5 is filled with the through holes by a filling method such as a printing method, and a conductive paste layer to be the external wiring 7 is formed by a screen printing method or the like, and heat treatment is performed, so The ceramic wiring substrate 1 having the wiring 5 and the external wiring 7 is produced. Also in this case, a plating layer similar to the above may be formed on the surface of the external wiring 7 and the end of the internal wiring 5.

  The connection wiring 6 on the upper surface of the ceramic wiring board 1 may be formed by simultaneous firing with the ceramic insulating layer 8 as with the external wiring 7, or the ceramic wiring board 1 without the connection wiring 6 is produced, After the upper surface is flattened by polishing or the like, it may be formed by a metallizing method such as a so-called Moriman method. Alternatively, the ceramic wiring substrate 1 without the connection wiring 6 may be produced and formed by a thin film forming method such as a vapor deposition method, a sputtering method, or an ion plating method. Similarly, the external wiring 7 may be formed by a thin film forming method. In the case of the metallization method, for example, a conductor containing metal powder such as tungsten (W), molybdenum (Mo), manganese (Mn), and a suitable resin binder and solvent at a predetermined position of the ceramic wiring substrate 1 by screen printing or the like. It is produced by applying a paste and heat-treating it at a high temperature of 1400 ° C or higher. A plating layer similar to the above may also be formed on the surface of the connection wiring 6. In the case of the thin film forming method, a base conductor layer made of, for example, a chromium (Cr) -Cu alloy layer or a titanium (Ti) -Cu alloy layer having a thickness of about 0.1 μm to 3 μm is formed on the entire upper surface of the ceramic wiring substrate 1. A resist film having a pattern-shaped opening of the connection wiring 6 is formed thereon, and a main conductor having a thickness of about 2 μm to 10 μm made of a metal such as copper or gold by plating or the like using the resist film as a mask. Form a layer. Then, the connection film 6 is formed by peeling off the resist film and removing the exposed portion of the underlying conductor layer by etching. A nickel or gold plating layer may be further formed on the surface by plating.

  According to the wiring board of the present invention, as in the example shown in FIGS. 1 to 3, the periphery of the connection portion between the via conductor 4 and the end of the internal wiring 5 has a Young's modulus higher than that of the insulating resin of the insulating resin layer 2. Since it is covered with the large fixing material 9, the periphery of the connection portion between the via conductor 4 formed in the lowermost insulating resin layer 2 and the end of the internal wiring 5 is fixed by the fixing material 9 and is not easily deformed. . As a result, the thermal stress applied to the connecting portion is reduced, and a highly reliable wiring board with reduced possibility of disconnection is obtained.

The fixing material 9 is made of a material having a Young's modulus larger than that of the insulating resin of the insulating resin layer 2 and may be formed of glass, ceramics, resin, metallized metal, and a mixture thereof. The Young's modulus of the fixing material 9 is preferably about twice or more that of the insulating resin of the insulating resin layer 2. When the fixing material 9 is glass, ceramics, or metallized metal, the Young's modulus is 10 times or more that of the insulating resin of the insulating resin layer 2. If the fixing material 9 is made of a resin, for example, a polyamideimide resin (Young's modulus: 3 GPa) is used for the insulating resin of the insulating resin layer 2 and a polyimide resin (Young's modulus: 12 GPa) is used for the fixing material 9. Is mentioned. As the fixing material 9, the same resin component as that of the insulating resin layer 2 is used and the Young's modulus is increased by adding a filler made of insulating inorganic powder such as alumina or silica (SiO ₂ ). May be. For example, by adding 30% by mass of fused silica powder as a filler to a polyamideimide resin having a Young's modulus of 3 GPa, the Young's modulus is about 10 GPa. By adding such a filler, the thermal expansion coefficient of the fixing material 9 can be brought close to the thermal expansion coefficient of the ceramic insulating layer 8, and the bonding between the fixing material 9 and the ceramic insulating layer 8 becomes stronger. Reliability can be increased.

  The shape of the fixing material 9 in plan view is not particularly limited, and may be a circular shape such as a circle, an ellipse, or an oval, or a polygonal shape such as a rectangle or a hexagon. Since the distance from the connection portion to the outer side of the fixing material 9 is equal to the circular shape of the via conductor 4 having a circular shape, the fixing material 9 is resistant to stress from a specific direction. Since it is not easy to deform, it is preferably formed in a circular shape.

  In addition, the fixing material 9 is formed so as to protrude from the upper surface of the ceramic wiring substrate 1 and is covered with the insulating resin of the lowermost insulating resin layer 2 as in the example shown in FIGS. Become. In this case, the fixing material 9 that covers the connection portion rounds the outer peripheral edge portion of the upper surface or forms an inclined surface with a lower outer side, as in the example shown in FIGS. 2B and 2C. Thus, the stress applied from the lateral direction to the fixing material 9 covering the connection portion due to the thermal expansion of the lowermost insulating resin layer 2 is dispersed in the vertical direction, and the stress applied from the lateral direction to the connection portion is reduced. This is preferable because a more reliable wiring board is obtained in which the possibility of disconnection at the portion is further reduced. If the roundness or inclined surface of the upper surface of the fixing material 9 is larger and is provided over the entire area from the outer peripheral edge portion to the side surface of the via conductor 4, the stress is more effectively distributed, and the force for pressing the connection portion from above Therefore, the possibility of disconnection at the connection portion is further reduced, and a highly reliable wiring board is obtained.

  Further, as the fixing material 9 covering the connection portion is higher in height (H shown in FIG. 2A), the stress applied in the lateral direction is increased by the thermal expansion of the insulating resin layer 2 as the lowermost layer around the connection portion. Therefore, the height H is preferably suppressed to 2/3 or less of the thickness of the lowermost insulating resin layer 2 (T shown in FIG. 2A), and the Young's modulus of the fixing material 9 is the insulating resin layer 2. When it is less than twice the Young's modulus of the insulating resin, it is preferable to suppress it to 1/2 or less of the thickness T of the lowermost insulating resin layer 2.

  When the fixing material 9 is made of a resin, the fixing material 9 covering the connecting portion can be formed by applying a varnish-like insulating resin precursor around the connecting portion by a printing method or a dispensing method and curing it. it can. By adjusting the viscosity and the coating amount of the varnish-like insulating resin precursor at this time, the roundness and the inclined surface of the upper surface of the fixing material 9 can be formed from the outer peripheral edge to the side surface of the via conductor 4. it can. Alternatively, a photosensitive varnish-like insulating resin precursor is applied to the entire upper surface of the ceramic wiring substrate 1 by a spin coating method or the like, and a resist having an opening that exposes the periphery of the connection portion is formed and exposed. You may form the fixing material 9 which covers a connection part by making it harden | cure. At this time, by exposing with diffused light, as in the example shown in FIGS. 2B and 2C, a rounded or inclined surface can be formed on the outer peripheral edge of the upper surface. Or, after applying and curing the varnish-like insulating resin precursor up to the connection portion, that is, covering the upper surface of the connection wiring 6 by the above two methods, an opening through which the connection portion is exposed by a laser may be provided. Alternatively, when the through hole for the via conductor 4 is formed in the lowermost insulating resin layer 2, an opening may be provided at the same time.

  When the fixing material 9 is made of glass or ceramics, a paste mainly composed of these is printed on the ceramic wiring substrate 1 by a method such as a screen printing method, and the paste is applied to the upper surface of the ceramic wiring substrate 1. Just baked into. It is preferable to bake at a temperature lower than the firing temperature of the ceramic wiring board 1 so that the ceramic wiring board 1 is not warped by the heating at this time. For example, a low-melting glass and a low-melting glass paste in which a filler such as alumina powder and a plasticizer, an organic solvent, etc. for matching the thermal expansion coefficient with the ceramic insulating layer 8 are mixed into a predetermined shape by a method such as screen printing. What is necessary is just to carry out printing application | coating on the upper surface of the layer 8, and to glaze at the temperature near melting | fusing point of low melting glass.

  When the fixing material 9 is made of metallized metal, it can be formed in the same manner as the method of forming the connection wiring 6 by the metallization method described above, and the fixing material 9 is formed at the same time when the connection wiring 6 is formed by the metallization method. May be.

  When the fixing material 9 is made of glass, ceramics, or metallized metal, an opening through which the connection portion is exposed by a laser may be provided after applying and baking a paste so as to cover the upper surface of the connection wiring 6.

  When the fixing material 9 is an insulating material such as resin or glass or ceramics, the fixing material 9 connected to the connection conductor 6 and the via conductor 4 is not conductive. The wiring board 1 has a reduced possibility of being disconnected at the connection portion between the via conductor 4 and the end of the internal wiring 5 without lowering the wiring density of the wiring board 1 because the short circuit does not occur even if the wiring is small. This is preferable.

  The insulating resin layer 2 is composed of polyimide resin, polyamideimide resin, siloxane modified polyamideimide resin, siloxane modified polyimide resin, polyphenylene sulfide resin, wholly aromatic polyester resin, BCB (benzocyclobutene) resin, epoxy resin, bismaleimide triazine resin, It is made of an insulating resin such as polyphenylene ether resin, polyquinoline resin, or fluorine resin.

  In order to form the insulating resin layer 2 on the ceramic wiring substrate 1, for example, when made of polyimide resin, a varnish-like polyimide precursor is applied to the upper surface of the ceramic wiring substrate 1 by spin coating, die coating, or curtain coating. The film is applied by a coating method such as a printing method or the like, and then cured by heat at about 400 ° C. to form a polyimide, thereby forming a thickness of about 10 μm to 50 μm. Alternatively, a resin adhesive such as a siloxane-modified polyamideimide resin, a siloxane-modified polyimide resin, a polyimide resin, a bismaleimide triazine resin, or an epoxy resin is dried on the lower surface of a sheet of about 10 μm to 50 μm made of the above resin with a dry thickness of about 5 μm to 20 μm. An adhesive layer is formed by applying and drying by a coating method such as a doctor blade method, and the adhesive layer is formed on the ceramic wiring substrate 1 by heating and pressing. In any method, the plurality of insulating resin layers 2 are formed by forming the via conductors 4 and the wiring layers 3 in the insulating resin layer 2 and repeating the above steps as many times as the number of necessary insulating resin layers 2. In the method using a film-shaped resin, a plurality of films can be pressed at once, and it is not necessary to apply and cure for each layer, so that the manufacturing process can be shortened.

Since the via conductor 4 is formed in the insulating resin layer 2, a through hole having a diameter of 20 μm to 100 μm is formed in this portion. This through hole is formed by first forming a resist film having an opening in the insulating resin layer 2 and etching the insulating resin layer 2 located in the opening of the resist film or using a laser to directly form the insulating resin. Formed by removing part of layer 2. An excimer laser, a CO ₂ laser, or the like can be used as the laser at this time, but the shape of the inner wall of the through hole can be adjusted to be nearly vertical, and the inner wall surface of the through hole can be processed smoothly, and is formed with an ultraviolet laser. It is desirable to keep it. Alternatively, in the case of a method of applying a varnish-like resin, a photosensitive resin is used, for example, a portion other than a portion where a through-hole is formed by exposure is cured, and a resin in a portion where the through-hole is formed is obtained. The through hole may be formed by removing by etching.

  First, the wiring layer 3 is formed by, for example, chromium (Cr) having a thickness of about 0.1 μm to 3 μm on the entire main surface of the insulating resin layer 2 by a thin film forming method such as vapor deposition, sputtering, or ion plating. ) -Copper (Cu) alloy layer or titanium (Ti) -copper (Cu) alloy layer. Next, a resist film having a pattern-shaped opening of the wiring layer 3 is formed on the underlying conductor layer, and the resist film is used as a mask to form a metal having a low electrical resistance such as copper or gold by plating or the like. A main conductor layer having a thickness of about 10 μm is formed. Then, the wiring layer 3 is formed by removing the resist film and removing the exposed portion of the underlying conductor layer by etching. Similar to the external wiring 7, a nickel or gold plating layer may be formed on the surface of the uppermost wiring layer 3 by plating.

  When the wiring layer 3 is formed with a recess having the same shape as the wiring layer 3 in the insulating resin layer 2 as in the example shown in FIG. 3 and the wiring layer 3 is formed in the recess, the upper surface of the insulating resin layer 2 is formed. Since there is no step between the wiring layer 3 and the upper surface of the wiring layer 3, the upper surface of the wiring substrate is flat even if a plurality of insulating resin layers 2 are stacked, and the wiring layer 3 on the upper surface of the uppermost insulating resin layer 2. It is preferable because an electronic component and a probe pin can be connected better. In order to form a recess in the insulating resin layer 2, a resist film having a pattern-shaped opening of the wiring layer 3 is formed on the surface of the insulating resin layer 2, and the insulating resin layer is etched by an etching method such as RIE (Reactive Ion Etching). The surface of the exposed portion of 2 may be removed.

  Before forming the wiring layer 3, the via conductor 4 is formed by filling a through hole of the insulating resin layer 2 with a conductive paste mainly composed of metal powder such as copper and resin, as shown in FIGS. As shown in the example shown in FIG. 3, a through hole filled with a conductor is formed. The conductor paste is made of a metal powder such as copper, a resin, and a solvent, and is solidified by filling the through holes and then drying. Alternatively, when the wiring layer 3 is formed, it may be formed simultaneously with the wiring layer 3 by forming a base conductor layer and a main conductor layer also on the inner surface of the through hole. In this case, the via conductor 4 is formed by being attached to the inner surface of the through hole of the insulating resin layer 2, and the through hole is not filled with the conductor. When the plating thickness at the time of forming the main conductor layer is increased, the through holes can be filled with the conductor as in the examples shown in FIGS. When the via conductor 4 is formed at the same time as the wiring layer 3, the through hole is formed as in the example shown in FIGS. 1 to 3 so that the base conductor layer can be satisfactorily formed by a thin film on the inner surface of the through hole. It is preferable to make the shape so that the upper surface side of the insulating resin layer 2 becomes larger. The through hole having such a shape is controlled by etching conditions when the through hole is formed by etching, by adjusting the output of the laser when the through hole is formed by a laser, and when using a photosensitive resin, the exposure condition or etching is performed. Depending on conditions, a through hole having a desired size and shape can be formed.

  The probe card of the present invention comprises the above-described wiring board of the present invention and probe pins connected to the wiring layer 3 on the upper surface of the uppermost insulating resin layer 2. The probe pin is produced, for example, as follows and attached to the wiring board of the present invention. First, a female die of a plurality of probe pins is formed on one surface of a silicon wafer by etching, a metal made of nickel is deposited on the surface on which the female die is formed by plating, and the female die is embedded and embedded with nickel. Nickel on the wafer other than nickel is removed by processing such as etching to produce a silicon wafer in which nickel probe pins are embedded. Nickel probe pins embedded in the silicon wafer are bonded to the wiring layer 3 on the upper surface of the uppermost insulating resin layer 2 of the wiring substrate by a bonding material such as solder. Then, the probe card is obtained by removing the silicon wafer with an aqueous potassium hydroxide solution.

  The electronic device of the present invention includes the above-described wiring board of the present invention and an electronic component connected to the wiring layer 3 on the upper surface of the uppermost insulating resin layer 2. The electronic component is, for example, a semiconductor element such as an IC chip or a piezoelectric vibrator such as a crystal vibrator, and a passive element such as a chip capacitor is also mounted as necessary. Such an electronic component is connected to the wiring layer 3 by soldering, bonding with a conductive adhesive, or wire bonding.

1: Ceramic wiring board 2: Insulating resin layer 3: Wiring layer 4: Via conductor 5: Internal wiring 6: Connection wiring 7: External wiring 8: Ceramic insulating layer 9: Fixing material

Claims (4)

A plurality of insulating resin layers and a plurality of wiring layers are alternately laminated on the upper surface of the ceramic wiring substrate, and the wiring layers positioned above and below the insulating resin layer are connected by via conductors, and the insulating resin in the lowermost layer A wiring board in which a plurality of the via conductors formed in a layer and ends of a plurality of internal wirings led out from the inside of the ceramic wiring board are electrically connected;
Each of the plurality of connection portions between the plurality of via conductors and the end portions of the plurality of internal wirings is provided from the upper surface of the ceramic wiring board to the side surface of the via conductor and from the insulating resin of the insulating resin layer Further, the wiring board is covered with a fixing material having a high Young's modulus, and the plurality of fixing materials are independent of each other .   The wiring board according to claim 1, wherein the fixing material is an insulating material.   A probe card comprising: the wiring board according to claim 1; and a probe pin connected to the wiring layer on the upper surface of the uppermost insulating resin layer.   An electronic device comprising: the wiring board according to claim 1; and an electronic component connected to the wiring layer on the upper surface of the uppermost insulating resin layer.

Images