JP2011134827A - Multilayer wiring board and method of manufacturing the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a multilayer wiring board excellent in the flatness of an upper surface, and a method of manufacturing the same. <P>SOLUTION: The multilayer wiring board is composed by alternately laminating a plurality of resin insulating layers 1 and a plurality of thin-film conductor layers 2 and electrically connecting the upper and lower thin-film conductor layers 2 with each other through a through conductor 3 formed on the resin insulating layer 1. The thin-film conductor layer 2 is housed inside a groove part 4 formed in the same pattern as the thin-film conductor layer 2 on the lower surface of the resin insulating layer 1 laminated on the upper side. The through conductor 3 is formed passing through the resin insulating layer 1 in the thickness direction so that a part of the lower part of the side face is exposed along the inner side face of the groove part 4, a part of the lower part of the side face exposed inside the groove part 4 of the through conductor 3 and the side face of the thin-film conductor layer 2 are brought into contact with each other, and the through conductor 3 and the thin-film conductor layer 2 are electrically connected. Since the thin-film conductor layer 2 is housed inside the groove part 4 and the side face of the through conductor 3 is in contact with the side face of the thin-film conductor layer 2, the deformation of the resin insulating layer 1 on the upper side is suppressed and the flatness is improved. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a multilayer wiring board in which a plurality of resin insulating layers and a plurality of thin film conductor layers are alternately laminated, and a method for manufacturing the same, and more particularly to a multilayer wiring board excellent in surface flatness such as an upper surface and the like. It relates to the manufacturing method.

  Conventionally, as a multilayer wiring board for connecting a semiconductor element to a terminal on the upper surface and electrically connecting a connection pad on the lower surface electrically connected to the terminal to an external electric circuit, a plurality of resin insulation layers and a plurality of A multilayer wiring board in which thin film conductor layers are alternately stacked is known. Such a multilayer wiring board is used, for example, as a so-called probe card board for performing an electrical check of a semiconductor element.

  The thin film conductor layer is formed so that a part is exposed on the lower surface and the upper surface of the multilayer wiring board, and the exposed portion on the upper surface is connected to the electrode of the semiconductor element and, for example, a probe bonded to the thin film conductor layer. The portion that is electrically connected and exposed on the lower surface is electrically connected to an external electric circuit board such as a device for measuring electrical characteristics. Then, the electrode of the semiconductor element and the external electric circuit are electrically connected through the probe, the thin film conductor layer, and the through conductor, and inspection such as operation check of the semiconductor element is performed.

  In general, such a multilayer wiring board is generally formed of a resin material such as an epoxy resin into a sheet shape to form a resin insulation layer, and then a main surface of the resin insulation layer such as a sputtering method or a plating method. A thin film conductor layer made of titanium, copper, gold or the like is deposited by a method, and a pattern formation technique such as a photolithographic method or an etching method is applied to the thin film conductor layer as necessary to obtain a predetermined pattern. It is manufactured by repeating each step of laminating another resin insulation layer on the resin insulation layer to which the thin film conductor layer is applied. The number of layers of the multilayer wiring board is adjusted according to the number of repetitions of this step, and after laminating to the required number of layers, the laminate is pressed to adhere each layer.

  In some cases, a ceramic multilayer wiring board is bonded to the lower side of the lowermost resin insulating layer in order to ensure rigidity as the multilayer wiring board. In this case, the wiring conductor of the ceramic multilayer wiring board is electrically connected to the thin film wiring conductor of the multilayer wiring board, and the wiring conductor of the ceramic multilayer wiring board and the external electric circuit are electrically connected to each other. An element and an external electric circuit can be electrically connected.

JP2004-253512

  However, in such a multilayer wiring board and a method for manufacturing the same, the resin insulating layer laminated thereon is convex at the portion where the thin film wiring conductor is formed, affected by the thickness of the thin film wiring conductor layer. There was a problem that it was easily deformed.

  When a part of the resin insulating layer is deformed in this way, the uppermost resin insulating layer is also deformed, and the flatness of the upper surface of the multilayer wiring board may be lowered. If the flatness of the upper surface of the multilayer wiring board becomes low, for example, it becomes difficult to electrically connect the plurality of thin film wiring conductors on the upper surface to the plurality of electrodes of the semiconductor element through the probe, respectively. This causes a problem that

  The present invention has been completed in view of the above problems of the prior art, and an object of the present invention is to provide a multilayer wiring board excellent in flatness of the upper surface and a manufacturing method thereof.

  In the multilayer wiring board of the present invention, a plurality of resin insulation layers and a plurality of thin film conductor layers made of a thermoplastic resin material are alternately laminated, and the upper and lower thin film conductors are interposed through through conductors formed in the resin insulation layer. A multilayer wiring board in which layers are electrically connected to each other, wherein the thin film conductor layer is accommodated in a groove formed in the same pattern as the thin film conductor layer on the lower surface of the resin insulating layer laminated on the upper side. The through conductor is formed through the resin insulating layer in the thickness direction so that a part of the lower portion of the side surface is exposed along the inner side surface of the groove portion. A portion of the lower portion of the side surface exposed to the side surface and the side surface of the thin film conductor layer are in contact with each other, and the through conductor and the thin film conductor layer are electrically connected.

The method for producing a multilayer wiring board according to the present invention comprises a step of preparing a first resin insulating layer made of a thermoplastic resin material and forming a thin film conductor layer on the upper surface of the first resin insulating layer;
Preparing a second resin insulation layer made of a thermoplastic resin material, and forming a groove in the same pattern as the thin film conductor layer on the lower surface of the second resin insulation layer;
A through-hole penetrating the second resin insulating layer in the thickness direction is formed at a position where a part of the outer periphery overlaps the inner side surface of the groove part, and a part of the lower part of the side surface of the groove part is formed in the through-hole. Arranging the through conductor so as to be exposed along the inner surface;
The second resin insulation layer is placed on the upper surface of the first resin insulation layer, the thin film conductor layer is contained in the groove, and a part of the lower portion of the side surface exposed in the groove of the through conductor is And laminating the thin film conductor layer so as to be in contact with the side surface of the thin film conductor layer, and pressurizing the laminated body while heating.

  According to the multilayer wiring board of the present invention, the thin film conductor layer is accommodated in the groove formed in the same pattern as the thin film conductor layer on the lower surface of the resin insulating layer laminated on the upper side. The influence of the thickness of the resin insulating layer on it is effectively suppressed.

  The through conductor is formed through the resin insulating layer in the thickness direction so that a part of the lower portion of the side surface is exposed along the inner side surface of the groove portion, and the side conductor exposed in the groove portion of the through conductor is formed. Compared to the case where the lower end of the through conductor is in contact with the thin-film wiring conductor because a part of the lower portion and the side surface of the thin-film conductor layer are in contact and the through conductor and the thin film conductor layer are electrically connected. For example, when the lower portion of the through conductor extends in a direction in contact with the thin film wiring conductor during pressurization, it is possible to effectively suppress the upper end of the through conductor from becoming higher than the upper surface of the resin insulating layer. Therefore, it is possible to effectively suppress the upper thin film conductor layer and a part of the resin insulating layer thereon from being deformed into a convex shape at the portion where the through conductor is formed.

  According to the multilayer wiring board manufacturing method of the present invention, the thin film wiring conductor layer formed on the upper surface of the lower first resin insulating layer including the above-described steps is formed on the lower surface of the second resin insulating layer. Since the second resin insulation layer is stacked on the first resin insulation layer in the groove formed in the same pattern as the layer, the influence of the thickness of the thin film wiring conductor on the upper surface of the first resin insulation layer Are effectively suppressed from being received by the second resin insulating layer thereon, and can be laminated.

  In addition, the through conductor is disposed in the second resin insulating layer as in the above configuration, and a part of the lower portion of the side surface of the through conductor is laminated so as to contact the side surface of the thin film conductor layer, and this laminate is heated. In other words, with respect to the through conductor arranged so that a part of the lower side of the through conductor is in contact with the side surface of the thin film wiring conductor, the side surface of the thin film wiring conductor in the groove is heated and pressurized. Since it can be deformed by extending to the side, it is possible to effectively prevent the upper surface of the through conductor from becoming higher than the upper surface of the resin insulating layer that shrinks in the thickness direction by pressurization. Therefore, in the portion where the through conductor is formed, while effectively suppressing the thin film wiring conductor layer on the upper side and further part of the resin insulation layer above it from being deformed into a convex shape, the multilayer wiring A substrate can be manufactured.

  Therefore, according to the multilayer wiring board and the manufacturing method thereof of the present invention, it is possible to provide a multilayer wiring board excellent in flatness of the upper surface and a manufacturing method thereof.

It is sectional drawing which shows an example of embodiment of the multilayer wiring board of this invention. (A)-(d) is sectional drawing which shows an example of the manufacturing method of the multilayer wiring board of this invention in order of a process, respectively. It is a principal part enlarged top view which shows the state which looked at the principal part in the process shown in FIG.2 (d) from the upper side.

  A multilayer wiring board according to the present invention will be described in detail with reference to the accompanying drawings.

  FIG. 1 is a sectional view showing an example of an embodiment of a multilayer wiring board according to the present invention. In FIG. 1, 1 is a resin insulating layer, 2 is a thin film conductor layer, 3 is a through conductor, and 4 is a groove. A plurality of resin insulation layers 1 and a plurality of thin film conductor layers 2 are alternately laminated, and upper and lower thin film conductor layers 2 are electrically connected to each other through through conductors 3 formed in the resin insulation layer 1 to form a multilayer wiring. The substrate is basically constructed.

  In the example shown in FIG. 1, a ceramic wiring substrate 6 is bonded to the lower surface of the lowermost resin insulating layer 1. The ceramic wiring board 6 is for improving characteristics such as rigidity of the multilayer wiring board, and a wiring conductor (not shown) is formed from the upper surface to the lower surface.

  Then, the thin film wiring conductor 2 on the upper surface of the multilayer wiring board is electrically connected to the electrode of the semiconductor element (not shown) via a probe or the like, and the wiring conductor located on the lower surface of the ceramic wiring board (the thin film of the multilayer wiring board) The one that is electrically connected to the wiring conductor 2) is electrically connected to an external electric circuit such as a device for measuring electrical characteristics. Thereby, the electrode of the semiconductor element and the external electric circuit are electrically connected through the probe, the thin film conductor layer 2, the through conductor 3, and the wiring conductor, and inspection such as operation check of the semiconductor element is performed.

  Each insulating layer 1 has, for example, a square shape or a circular shape having a side dimension or diameter of about 25 mm to 300 mm in plan view. In the example shown in FIG. 1, the external dimensions and shapes are the same in a plan view, and the multilayer wiring board is laminated so as not to be uneven. The ceramic substrate 6 bonded to the lower surface of the multilayer wiring board also has the same external dimensions and shape as the insulating layer 1 in plan view.

  In other words, the multilayer wiring board has, for example, a square plate shape or a disk shape as a whole, and has an upper surface mounted with a semiconductor element (not shown) for mounting and electrical check (electrical check is performed on the semiconductor element). It is used as a part for temporary mounting to be applied or mounting for making a semiconductor device by electrically and mechanically connecting a semiconductor element to a multilayer wiring board. Examples of semiconductor elements include semiconductor integrated circuit elements such as ICs and LSIs, and micromachines (so-called MEMS elements) in which a minute electromechanical mechanism is formed on the surface of a semiconductor substrate.

  The insulating layer 1 has a thickness of, for example, about 25 to 100 μm and is made of a thermoplastic resin material such as a polyimide resin, a polyamideimide resin, a polyether ether ketone resin, or a liquid crystal polymer resin, and the resin material is formed into a film shape. It is produced by.

  The multilayer wiring board has a lower surface (the lower surface of the ceramic wiring substrate 6 bonded to the lower surface in the example shown in FIG. 1) facing an external electric circuit (not shown), and a predetermined portion such as a terminal of the external electric circuit. It becomes a part electrically connected with.

  The thin film conductor layer 2 on the lower surface of the multilayer wiring board, an external electric circuit electrically connected via the wiring conductor of the ceramic wiring board, and the electrode of the semiconductor element electrically connected to the thin film conductor layer 2 on the upper surface The thin film wiring conductor 2, the through conductor 3 and the ceramic substrate 6 are electrically connected via a conductive path. And a semiconductor element and an external electric circuit are electrically connected through a multilayer wiring board, and transmission / reception of various signals, electrical inspection of the semiconductor element, and the like are performed.

  That is, the thin film conductor layer 2 and the through conductor 3 function as a part of a conductive path that electrically connects the semiconductor element and the external electric circuit. The thin film conductor layer 2 is a circuit pattern, a pad pattern such as a quadrangle or a circle, and the like. For example, the thin film conductor layer 2 is formed as a circuit pattern having a line width of 20 to 50 μm and a thickness of about 3 to 18 μm. Yes. Further, the through conductor 3 has a circular shape, an elliptical shape, or the like in plan view, and is formed in a circular shape having a diameter of about 30 to 100 μm, for example.

  The thin film conductor layer 2 is made of a metal material such as titanium, chromium, copper, silver, palladium, gold, or platinum. The thin film conductor layer 2 can be formed, for example, by depositing a metal material such as titanium or copper on the surface of the insulating layer 1 by a method such as sputtering, vapor deposition, or plating.

  The through conductor 3 is made of a metal material such as tin-silver or tin-silver-copper solder. If the through conductor 3 is made of, for example, tin-silver solder, a through hole 5 is formed in the insulating layer 1 by a method such as drilling or laser processing, and a solder paste is formed in the through hole 5. Can be formed by a method of filling.

  In the multilayer wiring board of the present invention, the thin film conductor layer 2 is housed in the groove 4 formed in the same pattern as the thin film conductor layer 2 on the lower surface of the resin insulating layer 1 laminated on the upper side, The resin insulating layer 1 is formed through the resin insulation layer 1 in the thickness direction so that a part of the lower portion of the side surface is exposed along the inner side surface of the groove portion 4, and the lower portion of the side surface exposed in the groove portion 4 of the through conductor 3 is formed. The through conductor 3 and the thin film conductor layer 2 are electrically connected to each other and the side surface of the thin film conductor layer 2 is in contact with each other.

  According to such a multilayer wiring board, the thin film conductor layer 2 is accommodated in the groove 4 formed in the same pattern as the thin film conductor layer 2 on the lower surface of the resin insulating layer 1 laminated on the upper side. The effect of the thickness of the conductor layer 2 on the resin insulating layer 1 thereon is effectively suppressed.

  The through conductor 3 is formed so as to penetrate the resin insulating layer 1 in the thickness direction so that a part of the lower portion of the side surface is exposed along the inner side surface of the groove portion 4. Since the part of the lower part of the side exposed to the side and the side of the thin film conductor layer 2 are in contact with each other and the through conductor 3 and the thin film conductor layer 2 are electrically connected, the lower end of the through conductor 3 is the thin film wiring. Compared to the case where the conductor is in contact with the conductor (not shown), for example, the lower portion of the through conductor 3 extends in a direction in contact with the thin film wiring conductor 3 during pressurization. Can also be effectively suppressed. Therefore, it is possible to effectively suppress the upper thin film conductor layer 2 and a part of the resin insulating layer 1 thereon from being deformed into a convex shape at the portion where the through conductor 3 is formed. it can. Therefore, according to the multilayer wiring board of the present invention, it is possible to provide a multilayer wiring board excellent in flatness of the upper surface.

  Such a groove portion 4 is formed by, for example, a method in which a metal plate (not shown) processed into the same shape as the thin film conductor layer by a method such as an etching method is pressed on the surface of the resin insulating layer 1 to be recessed. Can do. Further, a mask material (not shown) is set on the surface of the resin insulation layer 1 so as to provide openings in the same pattern as the thin film conductor layer 2, and etching is applied to keep the surface portion of the resin insulation layer 1 constant. The groove portion 4 can also be formed by a method of removing with the same pattern as the thin film conductor layer 2 at a depth of.

  The through conductor 3 is formed by filling a conductor such as solder into the through hole 5 formed in the resin insulating layer 1 as described above. It is necessary to make it exposed along the inner surface of 4. Such a through-conductor 3 can be formed if a part of the side surface of the through-hole 5 overlaps the inner side surface of the groove 4. That is, the conductor (through conductor 3) filled in the through hole 5 is exposed in the groove 4 at a portion overlapping the inner surface of the groove 4. A method of filling the through hole 5 with the conductor will be described in detail later.

  Next, the manufacturing method of the multilayer wiring board of this invention is demonstrated, referring FIG. 2 (a)-(d). 2 (a) to 2 (d) are cross-sectional views showing the method for manufacturing a multilayer wiring board according to the present invention in the order of steps. In FIG. 2, the same parts as those in FIG.

  First, as shown in FIG. 2A, a first resin insulation layer 1a made of a thermoplastic resin material is prepared, and a thin film conductor layer 2 is formed on the upper surface of the first resin insulation layer 1a. As the thermoplastic resin material, various thermoplastic resins as described above can be used.

  The thin film conductor layer 2 is made of a metal material such as titanium, chromium, copper, silver, palladium, gold, or platinum as described above. The thin film conductor layer 2 is formed by, for example, depositing a metal material such as titanium as an adhesion layer (not shown) on the surface of the first resin insulating layer 1a with a thickness of about 1 μm by a sputtering method, and then forming an adhesion layer. It can be formed by depositing a metal material such as copper or gold on the surface as a conductor layer (not shown) with a thickness of about 3 to 18 μm by sputtering or plating.

  Next, as shown in FIG. 2 (b), a second resin insulating layer 1b made of a thermoplastic resin material is prepared, and groove portions are formed in the same pattern as the thin film conductor layer 2 on the lower surface of the second resin insulating layer 1b. 4 is formed.

  Since the groove 4 is for accommodating the thin film conductor layer 2 in a later step, it is necessary to form the groove 4 in the same pattern as the thin film conductor layer 2. Further, in order to make it easy to accommodate the thin film conductor layer 2, the groove portion 4 may be larger than the thin film conductor layer 2 (external dimensions and depth are increased). For example, if the thin-film conductor layer 2 has a linear pattern with a line width of about 20 μm and a height of about 18 μm, the groove 4 can be a linear groove with a line width of about 25 μm and a depth of about 18 μm. Good.

  For example, as described above, the groove 4 is processed on the surface of the resin insulating layer 1 (the lower surface of the second resin insulating layer 1b) in the same shape as the thin film conductor layer 2 by an etching method or the like. It can be formed by a method of pressing and denting a metal plate such as an aluminum alloy or steel material. In addition, a mask material is set on the surface of the resin insulating layer 1 (the lower surface of the second resin insulating layer 1b) so as to provide openings in the same pattern as the thin film conductor layer 2, and etching is applied to the resin insulating layer. The groove 4 can also be formed by a method of removing the surface of 1 (the lower surface of the second resin insulation layer 1b) with a constant depth and the same pattern as the thin film conductor layer 2. This etching process is performed by dry etching using plasma, for example.

  Next, as shown in FIG. 2 (c), a through hole 5 that penetrates the second resin insulating layer 1b in the thickness direction is formed at a position where a part of the outer periphery overlaps the inner side surface of the groove portion 4, and this penetration The through conductor 3 is disposed in the hole 5 so that a part of the lower portion of the side surface is exposed along the inner surface of the groove 4.

  The through hole 5 can be formed, for example, by subjecting the insulating layer 2 to a drilling process such as drilling or laser processing. The through hole 5 needs to be formed at a position where a part of the outer periphery overlaps the inner side surface of the groove part 4 because a part of the lower part of the side surface of the through conductor 3 disposed inside the through hole 5 needs to be exposed in the groove part 4. There is.

  What is necessary is just to set suitably about the range with which the through-hole 5 and the groove part 4 overlap according to the dimension of the through-hole 5, the shape and dimension of the groove part 4, etc. FIG. For example, if the through hole 5 has a circular shape with a diameter of about 30 to 100 μm, it may be formed at a position where a range of about 50% or less of the circumference overlaps with the groove portion 4 in plan view.

  As described above, the through conductor 3 is made of a metal material such as tin-silver solder. Such a through conductor 3 can be disposed in the through hole 5 by filling the through hole 5 with a paste of tin-silver solder, for example, by a screen printing method or the like.

  In this step, a part of the through conductor 3 having a volume corresponding to the shrinkage volume (about 10% of the thickness) of the thermoplastic resin at the time of lamination extends in a direction in contact with the thin film conductor layer 2, so that the upper layer portion of the through conductor 3 is formed. Flatten. In addition, the metal which becomes the penetration conductor 3 in the through-hole 5 in which a part of the outer periphery of the through-hole 5 overlaps with the inner surface of the groove 4, that is, the inner surface is interrupted in a part of the lower part of the outer periphery of the through-hole 5. When filling the material, for example, the groove portion 4 is filled with a resist material along a portion corresponding to the outer periphery of the through hole 5, and the solder paste that becomes the through conductor 3 is excessively added to the groove portion 4. You don't have to spread.

  As shown in FIG. 2D, the second resin insulation layer 1b is placed on the upper surface of the first resin insulation layer 1a, the thin film conductor layer 2 is accommodated in the groove 4, and the groove 4 of the through conductor 3 is accommodated. A part of the lower part of the side exposed at the side is laminated so as to be in contact with the side of the thin film conductor layer 2, and this laminated body (no symbol) is pressed while being heated.

  The alignment for accommodating the thin-film conductor layer 2 in the groove portion 4 is performed, for example, by aligning the outer shapes and dimensions of the first resin insulating layer 1a and the second resin insulating layer 1b. Can be performed by stacking them so that they match.

  An example of the state of the thin film conductor layer 2, the through hole 5, and the through conductor 3 accommodated in the groove 4 is shown in FIG. 3. FIG. 3 is an enlarged top view of the main part showing a state in which the main part in the step shown in FIG. 3, parts similar to those in FIG. 2 are denoted by the same reference numerals.

  The heating and pressurization of the laminated body brings the upper and lower first and second resin insulation layers 1a and 1b into close contact with each other, and the inner surface of the groove portion 4 formed larger than the thin film conductor layer 2 is thinned. This is a process for bringing the conductor layer 2 into close contact.

  For example, the first and second resin insulation layers 1a and 1b are made of a liquid crystal polymer resin having a thickness of about 25 μm, and the gap between the inner surface of the groove 4 and the thin film conductor layer 2 is about 10 μm. If it exists, about 2-4 Mpa is suitable as conditions for pressurization, and about 60 minutes at 60-300 degreeC is suitable as conditions for heating.

  Each of the above steps shows only two resin insulation layers 1 (first and second resin insulation layers 1a and 1b). By repeating these steps, three or more layers of resin insulation are shown. A multilayer wiring board made of layer 1 can be manufactured. In this case, if all the resin insulation layers 1 and the thin film conductor layers 2 are laminated and then the whole laminate is heated and pressed while being heated, the productivity of the multilayer wiring board is achieved. It is advantageous in increasing

  Further, with respect to the thin film conductor layer 2 to be deposited on the uppermost thin film conductor layer 2, that is, the thin film conductor layer 2 on the upper surface of the multilayer wiring board, the exposed surface is covered with a gold plating layer to suppress oxidation or probe. The pin connectivity may be improved.

  The terminals connected to the multilayer wiring board are arranged in 50 × 50 vertical and horizontal directions, and the adjacent spacing is 1 mm. The circuit board is arranged on the upper surface of the resin insulating substrate, and the electrode on the lower surface of the silicon substrate is 50 × A multilayer wiring board according to one embodiment of the multilayer wiring board of the present invention is used as a multilayer wiring board for electrically connecting semiconductor integrated circuit elements arranged in 50 vertical and horizontal rows and having an adjacent interval of 0.2 mm. A substrate and a multilayer wiring substrate according to the prior art as a comparative example were manufactured, and the flatness of each upper surface was measured and compared.

  The multilayer wiring board of the example was manufactured by laminating 10 square resin insulating layers made of liquid crystal polymer resin and having a thickness of 25 μm and a side dimension of 76 mm. The thin film conductor layer alternately laminated with the resin insulation layer is formed by a conductor layer made of copper having a thickness of 12 μm, and is formed by dry etching using plasma in advance on the lower surface of the resin insulation layer laminated thereon. It was designed to fit in the groove. The through conductor was formed by arranging tin-silver solder in a circular through hole having a diameter of about 50 μm formed in the resin insulating layer.

  The multilayer wiring board of the comparative example was produced in the same manner as the multilayer wiring board of the above example with the material and dimensions of the resin insulating layer and the material of the thin film wiring conductor layer and the through conductor. In the multilayer wiring board of this comparative example, no groove is formed in the resin insulating layer, and the through conductor is connected to the thin film wiring conductor through the resin insulating layer in the thickness direction at the position of the lower thin film wiring conductor. And a conventional technique of connecting the lower end of the through conductor to the thin film wiring conductor.

For the multilayer wiring boards of these Examples and Comparative Examples, the flatness of the upper surface was measured with a surface roughness meter. As a result, the maximum surface roughness R _max was 13 μm or less in the multilayer wiring board of the example, whereas the R _max was about 37 μm in the multilayer wiring board of the comparative example.

  As described above, it was confirmed that the flatness of the upper surface can be effectively improved in the multilayer wiring board of the present invention.

DESCRIPTION OF SYMBOLS 1 ... Resin insulation layer 1a ... 1st resin insulation layer 1b ... 2nd resin insulation layer 2 ... Thin film conductor layer 3 ... Through-conductor 4 ... Groove part 5 ... Through-hole 6 ... Ceramic wiring boards

Claims (2)

A plurality of resin insulation layers made of a thermoplastic resin material and a plurality of thin film conductor layers are alternately laminated, and the upper and lower thin film conductor layers are electrically connected to each other through through conductors formed in the resin insulation layer. The thin film conductor layer is housed in a groove formed in the same pattern as the thin film conductor layer on the lower surface of the resin insulating layer laminated on the upper side, and the through conductor is The resin insulating layer is formed in the thickness direction so that a part of the lower portion of the side surface is exposed along the inner surface of the groove portion, and the lower portion of the side surface exposed in the groove portion of the through conductor is formed. A multilayer wiring board, wherein a part and a side surface of the thin film conductor layer are in contact with each other, and the through conductor and the thin film conductor layer are electrically connected. Preparing a first resin insulation layer made of a thermoplastic resin material, and forming a thin film conductor layer on the upper surface of the first resin insulation layer;
Preparing a second resin insulation layer made of a thermoplastic resin material, and forming a groove in the same pattern as the thin film conductor layer on the lower surface of the second resin insulation layer;
A through-hole penetrating the second resin insulating layer in the thickness direction is formed at a position where a part of the outer periphery overlaps the inner side surface of the groove part, and a part of the lower part of the side surface of the groove part is formed in the through-hole. Arranging the through conductor so as to be exposed along the inner surface;
The second resin insulation layer is placed on the upper surface of the first resin insulation layer, the thin film conductor layer is contained in the groove, and a part of the lower portion of the side surface exposed in the groove of the through conductor is And a step of laminating the thin film conductor layer so as to be in contact with the side surface of the thin film conductor layer and pressurizing the laminated body while heating.

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