JP2016111244A - Wiring board and manufacturing method thereof - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a wiring board capable of improving reliability by preventing a glass substrate from being broken and suppressing warpage.SOLUTION: A wiring board 10 comprises a wiring lamination part 11, a first glass substrate 30, and a second glass substrate 40. The wiring lamination part 11 is structured by laminating resin insulation layers 21-23 and metal wiring layers 24-26. In the first glass substrate 30, a through-conductor 35 is provided, and in the second glass substrate 40, a through-conductor 45 is provided. In both the first glass substrate 30 and the second glass substrate 40, the through-conductors 35, 45 are tapered so as to enlarge outer diameters towards an outer layer side in the wiring board 10. In addition, stress mitigation layers 81, 82 are formed between the first glass substrate 30 and the wiring lamination part 11 and between the second glass substrate 40 and the wiring lamination part 11.SELECTED DRAWING: Figure 1

Description

  The present invention includes a wiring laminated portion having a structure in which a resin insulating layer and a metal wiring layer are laminated, a first glass substrate formed on a laminated portion main surface side of the wiring laminated portion, and a laminated portion rear surface side of the wiring laminated portion. A wiring board provided with the 2nd glass substrate formed, and its manufacturing method are related.

  In recent years, with the miniaturization of electrical equipment and electronic equipment, miniaturization and high density are also required for wiring boards mounted on these equipment. As such a wiring board, for example, a structure in which a build-up layer (wiring laminated portion) having a structure in which a resin insulating layer and a metal wiring layer are laminated is formed on both surfaces of a glass substrate has been proposed (for example, Patent Documents). 1). As another wiring board, an interposer is proposed in which an inorganic insulating layer made of glass or the like is laminated on the main surface and back surface of the resin layer, and through conductors that penetrate the inorganic insulating layers on the main surface side and back surface side are formed. (For example, refer to Patent Document 2). As another wiring substrate, a resin insulating layer and a metal wiring layer are alternately laminated, and a ceramic layer made of glass or the like is formed on the main surface and the back surface of the coreless wiring substrate not including the core substrate, respectively. (For example, refer to Patent Document 3).

Special table 2013-521663 gazette (FIG. 1 etc.) WO2011 / 125546 gazette (FIG. 1 etc.) JP 2008-98599 A (FIG. 3 etc.)

  However, the conventional techniques described in Patent Documents 1 to 3 have the following problems. That is, the conventional technique described in Patent Document 1 has a problem that the glass substrate is easily damaged because thermal stress is concentrated on the side surface of the glass substrate due to the difference in thermal expansion between the glass substrate and the resin insulating layer. Further, in the prior art described in Patent Document 2, a portion of the through conductor that penetrates the inorganic insulating layer on the main surface side has a tapered shape in which the outer diameter gradually increases as it goes to the inorganic insulating layer on the back surface side. Therefore, the stress applied to the wiring board during formation of the through conductor cannot be sufficiently relaxed. As a result, there is a problem that the wiring board is easily damaged or warped. Furthermore, in the prior art described in Patent Document 3, there is a problem that the ceramic layer is easily damaged or warped due to thermal history because the difference in thermal expansion between the ceramic layer and the coreless wiring board is large. From the above, when the conventional techniques described in Patent Documents 1 to 3 described above are employed, there is a high possibility that a problem will occur in the wiring board, and the yield of the wiring board will be reduced. Therefore, there is a problem that the predetermined reliability required for the wiring board cannot be given.

  The present invention has been made in view of the above problems, and an object of the present invention is to provide a wiring board capable of improving reliability by preventing breakage of the glass substrate and suppressing warpage. It is in. Another object is to provide a method for manufacturing a wiring board capable of manufacturing a wiring board having excellent reliability.

  As means (means 1) for solving the above-mentioned problem, a wiring laminated portion having a laminated portion main surface and a laminated portion back surface and having a structure in which a plurality of resin insulating layers and a plurality of metal wiring layers are laminated; A first glass substrate formed on the laminated portion main surface side and having a first substrate main surface and a first substrate back surface, and a second glass formed on the laminated portion back surface side and having a second substrate main surface and a second substrate back surface. A wiring substrate comprising a glass substrate, wherein the first glass substrate is electrically connected to the first substrate main surface side and the first substrate back surface side and electrically connected to the metal wiring layer. The first glass substrate is provided with a through conductor that is electrically connected to the metal wiring layer and is electrically connected to the second substrate main surface side and the second substrate back surface side. And between the wiring laminated portion and the first A stress relaxation layer is formed between the glass substrate and the wiring laminated portion, and in either the first glass substrate or the second glass substrate, the penetrating conductor gradually moves toward the outer layer side of the wiring substrate. There is a wiring board characterized in that it has a tapered shape with an increased outer diameter.

  Therefore, according to the invention described in the means 1, the wiring laminated portion is disposed in the inner layer portion of the wiring substrate, and the glass substrates (first glass substrate and second glass substrate) are disposed in the outer layer portion of the wiring substrate. Thermal stress resulting from the difference in thermal expansion between the substrate and the wiring laminate is distributed between the first glass substrate and the second glass substrate. As a result, the concentration of thermal stress on the side surface of the glass substrate is prevented, so that the glass substrate can be prevented from being damaged. In addition, since a stress relaxation layer is formed between the first glass substrate and the wiring laminated portion and between the second glass substrate and the wiring laminated portion, the difference in thermal expansion between the glass substrate and the wiring laminated portion. The concentration of thermal stress caused by the is surely relaxed by the stress relaxation layer. Further, in both the first glass substrate and the second glass substrate, the through conductor has a tapered shape in which the outer diameter gradually increases toward the outer layer side of the wiring board. The stress applied to is reliably relieved. Therefore, breakage and warpage of the glass substrate can be reliably prevented. From the above, since it is difficult for the glass substrate to be defective, the yield of the wiring substrate can be improved, and the reliability of the wiring substrate is improved.

  The wiring laminated portion constituting the wiring board has a structure in which a plurality of resin insulating layers and a plurality of metal wiring layers are laminated. The resin insulation layer can be appropriately selected in consideration of insulation, heat resistance, moisture resistance, and the like. Specific examples of the material for forming the resin insulation layer include thermosetting resins such as epoxy resins, phenol resins, urethane resins, silicone resins, and polyimide resins, cycloolefin resins, polycarbonate resins, acrylic resins, polyacetal resins, and polypropylene resins. A thermoplastic resin etc. are mentioned. In addition, composite materials of these resins and organic fibers such as glass fibers (glass woven fabrics and glass nonwoven fabrics) and polyamide fibers, or three-dimensional network fluorine-based resin base materials such as continuous porous PTFE, epoxy resins, etc. A resin-resin composite material impregnated with a thermosetting resin may be used.

  The metal wiring layer can be formed using various kinds of conductive metals such as copper, silver, gold, platinum, nickel, titanium, aluminum, chromium, etc. In particular, the metal wiring layer is preferably composed mainly of copper. As a method for forming the metal wiring layer, a known method such as a subtractive method, a semi-additive method, or a full additive method is employed. Specifically, for example, techniques such as etching of copper foil, electroless copper plating, or electrolytic copper plating are applied. It is also possible to form a metal wiring layer by etching after forming a thin film by a technique such as sputtering or CVD, or to form a metal wiring layer by printing a conductive paste or the like.

  The 1st glass substrate which comprises the said wiring board is formed in the lamination | stacking part main surface side of a wiring lamination | stacking part, and has a 1st board | substrate main surface and the 1st substrate back surface located in the other side. The second glass substrate constituting the wiring board is formed on the back surface side of the laminated portion of the wiring laminated portion, and has a second substrate main surface and a second substrate back surface located on the opposite side. The materials for forming the first glass substrate and the second glass substrate can be appropriately selected in consideration of cost, workability, insulation, mechanical strength, and the like. As the material for forming the first glass substrate and the second glass substrate, borosilicate glass, low-temperature fired glass ceramic, glass ceramic, or the like is preferably used.

  Further, the first glass substrate is provided with a through conductor that electrically connects the first substrate main surface side and the first substrate back surface side and is electrically connected to the metal wiring layer. A through conductor is provided that conducts the substrate main surface side and the second substrate back surface side and is electrically connected to the metal wiring layer. Such a through conductor is made of, for example, a conductive metal such as gold, silver, copper, platinum, palladium, nickel, tin, lead, or tungsten. In particular, the through conductor is preferably made of copper having high conductivity and low cost.

  The through conductor has a tapered shape in which the outer diameter gradually increases toward the outer layer side of the wiring board in both the first glass substrate and the second glass substrate. In addition, when a penetration conductor consists of copper, the Young's modulus of a penetration conductor becomes higher than the Young's modulus of a glass substrate (a 1st glass substrate and a 2nd glass substrate). Therefore, the higher the volume ratio of the through conductors in the glass substrate, the more difficult the glass substrate is deformed, and it is difficult to absorb the stress applied to the glass substrate. Therefore, in order to solve this problem, for example, among the first glass substrate and the second glass substrate, the taper ratio of the through conductor in the glass substrate having the higher volume ratio of the through conductor in the glass substrate is set so that the volume ratio is It can be considered that the taper ratio of the through conductor in the lower glass substrate is made larger. In this way, even if the glass substrate is difficult to absorb stress due to the high volume ratio of the through conductor, the stress can be reliably relaxed by increasing the taper ratio of the through conductor. For this reason, it is possible to more reliably prevent the glass substrate from being damaged or warped.

  In addition, although the magnitude | size of a taper ratio is not specifically limited, For example, it is good that it is 0.01 or more and 0.5 or less. If the taper ratio is less than 0.01, it is difficult to form a seed layer on the inner surface of the through hole when the through conductor is formed in the through hole. On the other hand, when the taper ratio is larger than 0.5, it becomes difficult to narrow the pitch of the through conductors. Here, the definition of the taper ratio described in this specification is based on JIS B0612, and the calculation method is based on JIS B0612. The taper ratio is calculated from the formula {(outer diameter of the through conductor on the outer layer side of the wiring board) − (outer diameter of the through conductor on the inner layer side of the wiring board)} / (thickness of the glass substrate).

  Moreover, the thickness ratio of the stress relaxation layer formed between the glass substrate having the higher volume ratio of the through conductor in the glass substrate and the wiring laminate portion of the first glass substrate and the second glass substrate is defined as the volume ratio. May be larger than the thickness of the stress relaxation layer formed between the lower glass substrate and the wiring laminate. Even in this case, the stress can be reliably relieved by increasing the thickness of the stress relieving layer in the glass substrate that is difficult to absorb stress due to the high volume ratio of the through conductor. Therefore, it is possible to more reliably prevent the glass substrate from being damaged or warped.

  Further, the number of through conductors and the minimum value of the pitch between adjacent through conductors may be different between the first glass substrate and the second glass substrate. In this case, when the terminal electrodes are formed on the upper surface (first substrate main surface) and the lower surface (second substrate back surface) of the wiring substrate, the pitch of the terminal electrodes is made different between the upper surface and the lower surface of the wiring substrate. be able to. Therefore, the degree of freedom of wiring provided on the wiring board is increased, and the wiring density can be increased.

  Furthermore, it is preferable that the semiconductor chip is mounted on the semiconductor chip mounting region set on the glass substrate having the smaller minimum pitch between adjacent through conductors among the first glass substrate and the second glass substrate. If it does in this way, a plurality of penetration conductors provided in a glass substrate and a plurality of connection terminals provided in the bottom of a semiconductor chip can be connected reliably.

  Here, examples of the semiconductor chip include an IC chip used as a microprocessor of a computer, and an IC chip such as a DRAM (Dynamic Random Access Memory) and an SRAM (Static Random Access Memory).

  In addition, a stress relaxation layer is formed between the first glass substrate and the wiring laminated portion and between the second glass substrate and the wiring laminated portion. The stress relaxation layer can be appropriately selected in consideration of insulation, heat resistance, moisture resistance, and the like. Materials for forming the stress relaxation layer include thermosetting resins such as epoxy resins, phenol resins, polyimide resins, silicone resins, and urethane resins, cycloolefin resins, polyolefin resins, polyamide resins, polycarbonate resins, acrylic resins, polyacetal resins, and polypropylene. Examples thereof include a thermoplastic resin such as a resin. In addition, a material obtained by adding an inorganic filler to these resins may be used. In this case, the content of the inorganic filler in the stress relaxation layer is preferably smaller than the content of the inorganic filler in the resin insulating layer. By doing so, even when the stress relaxation layer is formed of the same resin material as the resin insulating layer, the stress relaxation layer is softer than the resin insulating layer because the content of the inorganic filler in the stress relaxation layer is small. For this reason, the thermal stress applied to the first glass substrate and the second glass substrate can be more reliably relaxed by the stress relaxation layer.

  Here, examples of the inorganic filler include inorganic compound fillers and metal fillers. Among these, examples of the inorganic compound filler include ceramic fillers made of calcium carbonate, silicon oxide, aluminum oxide, talc, aluminum nitride, barium sulfate, and the like. Moreover, the dielectric filler which consists of barium titanate, strontium titanate, lead titanate, lead zirconate titanate, etc. is mentioned. As these inorganic fillers, only 1 type may be used and 2 or more types may be used together. Further, the shape of the filler is not particularly limited, and examples thereof include an indefinite shape, a spherical shape, a fiber shape, and a plate shape. As these fillers, only one kind may be used, or two or more kinds may be used in combination. Moreover, the stress relaxation layer does not need to contain the inorganic filler.

  The stress relaxation layer may be formed of the same material as the resin insulating layer, or may be formed of a material different from the resin insulating layer. When the stress relaxation layer is formed of the same material as that of the resin insulation layer, it is not necessary to prepare a material different from that of the resin insulation layer when forming the stress relaxation layer. Therefore, since the material necessary for manufacturing the wiring board is reduced, the cost of the wiring board can be reduced. On the other hand, when the stress relaxation layer is formed of a material different from that of the resin insulating layer, the function of the stress relaxation layer can be specialized to the function of relaxing the stress applied to the first glass substrate and the second glass substrate. .

  Moreover, as a method of forming a stress relaxation layer, a method of forming a stress relaxation layer by laminating a resin sheet, a method of forming a stress relaxation layer by printing a varnish (varnish printing), and a component in a varnish tank Method of forming a stress relaxation layer by immersing (varnish dip), Method of forming a stress relaxation layer by printing a resin using a curtain coater, Stress relaxation by thermocompression bonding of a resin sheet using a vacuum press Examples include a method of forming a layer.

  In addition, the stress relaxation layer formed between the first glass substrate and the wiring laminated portion may be formed on the laminated portion main surface of the wiring laminated portion, or on the first substrate back surface of the first glass substrate. It may be formed. Similarly, the stress relaxation layer formed between the second glass substrate and the wiring laminated portion may be formed on the back surface of the laminated portion of the wiring laminated portion, or the second substrate main surface of the second glass substrate. It may be formed on the top.

  The stress relaxation layer is preferably thinner than the resin insulating layer, the first glass substrate, and the second glass substrate. If it does in this way, it will become difficult for a wiring board to become thick. Further, since the amount of deformation of the stress relaxation layer when stress is applied is reduced by making the stress relaxation layer thin, the dimensional stability of the first glass substrate and the second glass substrate laminated through the stress relaxation layer is reduced. Can be prevented.

  As another means (means 2) for solving the above-mentioned problem, there is provided a method for manufacturing a wiring board according to the above means 1, wherein a first glass substrate preparing step of preparing at least a pair of the first glass substrates, A second glass substrate preparing step of preparing at least a pair of the second glass substrates in which the stress relaxation layer mainly composed of a resin insulating material is formed on the second substrate main surface; and the second glass substrate preparing step. A pasting step of temporarily bonding the pair of second glass substrates to each other via an adhesive portion in a state where the second substrate main surfaces of the pair of second glass substrates are directed to opposite sides; A wiring laminated portion forming step of forming the wiring laminated portion on the stress relaxing layer formed on the second substrate main surface; and after the wiring laminated portion forming step, the stress relaxing layer on the wiring laminated portion. Through the first glass A wiring board comprising: a glass substrate laminating step for laminating plates; and a separating step for separating the pair of second glass substrates temporarily bonded via the bonding portion after the glass substrate laminating step. There is a manufacturing method.

  Therefore, according to the invention described in the means 2, after the separation step, the wiring laminated portion is disposed on the inner layer portion of the obtained wiring substrate, and the glass substrates (first glass substrate and second glass substrate) are obtained. Since it is disposed in the outer layer portion of the wiring substrate thus formed, thermal stress caused by the difference in thermal expansion between the glass substrate and the wiring laminated portion is distributed to the first glass substrate and the second glass substrate. As a result, the concentration of thermal stress on the side surface of the glass substrate is prevented, so that the glass substrate can be prevented from being damaged. Moreover, a stress relaxation layer is formed between the second glass substrate and the wiring laminated portion by performing the wiring laminated portion forming step, and the first glass substrate and the wiring laminated portion are obtained by performing the glass substrate laminated step. Since the stress relaxation layer is formed between them, the concentration of thermal stress due to the difference in thermal expansion between the glass substrate and the wiring laminated portion is reliably relaxed by the stress relaxation layer. Further, in both the first glass substrate and the second glass substrate, the through conductor has a tapered shape in which the outer diameter gradually increases toward the outer layer side of the wiring board. The stress applied to is reliably relieved. Therefore, breakage and warpage of the glass substrate can be reliably prevented. From the above, since it is difficult for the glass substrate to be defective, the yield of the wiring substrate can be improved, and the reliability of the wiring substrate is improved.

1 is a schematic cross-sectional view showing a wiring board in the present embodiment. Explanatory drawing which shows a 2nd glass substrate preparation process. Explanatory drawing which shows a sticking process. Explanatory drawing which shows a wiring laminated part formation process. Explanatory drawing which shows a glass substrate lamination process. Explanatory drawing which shows the process of forming a 1st through-hole in a 1st glass substrate. Explanatory drawing which shows the process of forming a 1st penetration conductor in a 1st penetration hole. Explanatory drawing which shows a separation process.

  Hereinafter, an embodiment embodying the present invention will be described in detail with reference to the drawings.

  As shown in FIG. 1, the wiring board 10 of this embodiment is a wiring board for mounting the IC chip 71. The wiring substrate 10 includes a substantially rectangular plate-shaped wiring laminated portion 11, a first glass substrate 30 formed on the laminated portion main surface 12 (upper surface in FIG. 1) side of the wiring laminated portion 11, and the laminated wiring portion 11. It consists of the 2nd glass substrate 40 formed in the partial back surface 13 (FIG. 1 lower surface) side.

  The wiring laminated portion 11 has a laminated portion main surface 12 and a laminated portion rear surface 13 and has a substantially rectangular plate shape of 20 mm long × 20 mm wide × 60 μm thick. Further, the wiring laminated portion 11 includes three resin insulating layers 21, 22, and 23 made of thermosetting resin (cycloolefin resin) to which an inorganic filler (silica filler) is added, and three metal wiring layers made of copper. 24, 25, and 26 are stacked. The resin insulating layers 21 to 23 of the present embodiment have a coefficient of thermal expansion of about 10 to 60 ppm / ° C. (specifically 46 ppm / ° C.) in a completely cured state and a Young's modulus of 8 GPa. In addition, the thermal expansion coefficient in the completely cured state of the resin insulating layers 21 to 23 refers to an average value of measured values between 25 ° C. and 150 ° C. In addition, via conductors 27 formed by copper plating are provided in the resin insulating layers 21 to 23, respectively.

  As shown in FIG. 1, the first glass substrate 30 has a first substrate main surface 31 (upper surface in FIG. 1), a first substrate rear surface 32 (lower surface in FIG. 1), and a first substrate side surface 33. It has a substantially rectangular plate shape of 20 mm × width 20 mm × thickness 100 μm. The first glass substrate 30 of the present embodiment is a substrate made of borosilicate glass. The first glass substrate 30 has a thermal expansion coefficient of less than 15 ppm / ° C. (specifically, about 4 to 5 ppm / ° C.) and a Young's modulus of 73 GPa. In addition, the thermal expansion coefficient of the 1st glass substrate 30 says the average value of the measured value between 30 degreeC-400 degreeC.

  The first glass substrate 30 has a plurality of first through holes 34 that are open in both the first substrate main surface 31 and the first substrate back surface 32 in a lattice shape. Each first through hole 34 has a circular shape in plan view, and has a tapered shape in which the inner diameter gradually increases toward the first substrate main surface 31 side. In the first through hole 34 of this embodiment, the inner diameter at the opening on the first substrate main surface 31 side is set to 60 μm, and the inner diameter at the opening on the first substrate back surface 32 side is set to 30 μm. A first through conductor 35 made of copper is provided in the first through hole 34. These first through conductors 35 are electrically connected to the first substrate main surface 31 side and the first substrate back surface 32 side, and are electrically connected to the metal wiring layers 24 to 26 of the wiring laminated portion 11. In addition, the Young's modulus of the 1st penetration conductor 35 is higher than the Young's modulus (73 GPa) of the 1st glass substrate 30, and is 118 GPa in this embodiment. The volume ratio of the first through conductor 35 to the first glass substrate 30 is 3.41%. Further, the first through conductor 35 has a taper shape in which the outer diameter gradually increases toward the outer layer side (that is, the first substrate main surface 31 side) of the wiring board 10. Specifically, the first through conductor 35 has an outer diameter of 60 μm on the first substrate main surface 31, an outer diameter of 30 μm on the first substrate back surface 32, and a taper ratio of 0.3. Moreover, the minimum value of the center-to-center distance (pitch) between the adjacent first through conductors 35 is set to 200 μm.

  As shown in FIG. 1, main surface side terminal electrodes 36 made of copper are formed in an array at a plurality of locations on the first substrate main surface 31 of the first glass substrate 30. Each main surface side terminal electrode 36 is electrically connected to the first through conductor 35. Each main surface side terminal electrode 36 has a circular shape in plan view, and has an outer diameter (90 μm in this embodiment) larger than the maximum diameter (60 μm) of the first through conductor 35. In addition, the thickness of each main surface side terminal electrode 36 in the present embodiment is set to 10 μm.

  Furthermore, the first substrate main surface 31 of the first glass substrate 30 is almost entirely covered with a solder resist layer 51 made of epoxy resin and having a thickness of about 30 μm. An opening 52 for exposing the main surface side terminal electrode 36 is formed at a predetermined position of the solder resist layer 51. A plurality of solder bumps 53 are disposed on the surface of the main surface side terminal electrode 36. Each solder bump 53 is electrically connected to a surface connection terminal 72 of an IC chip 71 (semiconductor chip). The IC chip 71 of the present embodiment is a plate-like object having a rectangular shape in plan view of 12.0 mm in length, 12.0 mm in width, and 0.9 mm in thickness, and has a thermal expansion coefficient of about 3 to 4 ppm / ° C. (specifically (Specifically, about 3.5 ppm / ° C.) of silicon. Note that an area formed by each main surface side terminal electrode 36 and each solder bump 53 is an IC chip mounting area 73 (semiconductor chip mounting area) in which the IC chip 71 can be mounted. The IC chip mounting region 73 is a glass substrate having a smaller minimum pitch between adjacent through conductors 35 and 45 of the first glass substrate 30 and the second glass substrate 40 (in this embodiment, the first glass substrate 30). ) Is set on the surface.

  As shown in FIG. 1, a first stress relaxation layer mainly composed of a resin insulating material (cycloolefin resin) to which an inorganic filler (silica filler) is added is provided between the first glass substrate 30 and the wiring laminated portion 11. 81 is formed. That is, the first stress relaxation layer 81 is formed of the same material as the resin insulating layers 21 to 23. The Young's modulus of the first stress relaxation layer 81 is the Young's modulus (73 GPa) of the first glass substrate 30, the Young's modulus (118 GPa) of the first through conductor 35, and the Young's modulus (8 GPa) of the resin insulating layers 21 to 23. 2GPa in this embodiment. Moreover, the content rate of the inorganic filler of the 1st stress relaxation layer 81 is smaller than the content rate (about 45 volume%) of the inorganic filler of the resin insulating layers 21-23, and is 30 volume% in this embodiment. The first stress relaxation layer 81 has a substantially rectangular plate shape of 20 mm long × 20 mm wide × 5 μm thick.

  Further, the first stress relaxation layer 81 is formed with a plurality of first through holes 83 penetrating the first stress relaxation layer 81 in the thickness direction. Each first through hole 83 has a circular shape in plan view, and has a tapered shape in which the inner diameter gradually decreases toward the first substrate back surface 32 side. In the first through hole 83 of the present embodiment, the inner diameter of the opening on the first substrate back surface 32 side is set to 30 μm, and the inner diameter of the opening on the laminated portion main surface 12 side is set to 35 μm. In the first through hole 83, one end portion (the lower end portion in FIG. 1) of the first through conductor 35 is disposed.

  As shown in FIG. 1, the second glass substrate 40 has substantially the same structure as the first glass substrate 30 described above. That is, the second glass substrate 40 has a second substrate main surface 41 (upper surface in FIG. 1), a second substrate rear surface 42 (lower surface in FIG. 1), and a second substrate side surface 43, and is 20 mm long × 20 mm wide × thick. It has a substantially rectangular plate shape with a thickness of 200 μm. The second glass substrate 40 of the present embodiment is a substrate made of borosilicate glass. The second glass substrate 40 has a thermal expansion coefficient of less than 15 ppm / ° C. (specifically, about 4 to 5 ppm / ° C.) and a Young's modulus of 73 GPa. In addition, the thermal expansion coefficient of the 2nd glass substrate 40 says the average value of the measured value between 30 degreeC-400 degreeC.

  Further, the second glass substrate 40 is formed with a plurality of second through holes 44 that are opened in both the second substrate main surface 41 and the second substrate back surface 42 in a lattice shape. Each of the second through holes 44 has a circular shape in a plan view, and has a tapered shape in which the inner diameter gradually increases toward the second substrate back surface 42 side. In the second through hole 44 of the present embodiment, the inner diameter at the opening on the second substrate main surface 41 side is set to 60 μm, and the inner diameter at the opening on the second substrate back surface 42 side is set to 100 μm. A second through conductor 45 made of copper is provided in the second through hole 44. The second through conductors 45 are electrically connected to the second substrate main surface 41 side and the second substrate back surface 42 side, and are electrically connected to the metal wiring layers 24 to 26 of the wiring laminated portion 11. The Young's modulus of the second through conductor 45 is higher than the Young's modulus (73 GPa) of the second glass substrate 40, and is 118 GPa in this embodiment. The volume ratio of the second through conductor 45 to the second glass substrate 40 is 1.13%. Further, the second through conductor 45 has a taper shape in which the outer diameter gradually increases toward the outer layer side of the wiring substrate 10 (that is, the second substrate back surface 42 side). Specifically, the second through conductor 45 has an outer diameter of 60 μm on the second substrate main surface 41, an outer diameter of 100 μm on the second substrate back surface 42, and a taper ratio of 0.2. In the present embodiment, the taper ratio (0.3) of the first through conductor 35 in the first glass substrate 30 (volume ratio 3.41%) with the higher volume ratio is the second with the lower volume ratio. The taper ratio (0.2) of the second through conductor 45 in the glass substrate 40 (volume ratio 1.13%) is larger. Further, the minimum value of the center-to-center distance (pitch) between the adjacent second through conductors 45 is larger than the minimum value (200 μm) of the pitch between the adjacent first through conductors 35, and is set to 900 μm in this embodiment. ing. Since the area of the second glass substrate 40 is equal to the area of the first glass substrate 30, the number of the second through conductors 45 on the side with the larger pitch is smaller than the number of the first through conductors 35 on the side with the smaller pitch. Become. That is, the number of through conductors 35 and 45 and the minimum pitch between adjacent through conductors 35 and 45 differ between the first glass substrate 30 and the second glass substrate 40.

  As shown in FIG. 1, main surface side terminal electrodes 46 made of copper are formed in an array at a plurality of locations on the second substrate main surface 41 of the second glass substrate 40. The back-side terminal electrodes 47 made of copper are also formed in an array at a plurality of locations on the back surface 42 of the two substrates. Each terminal electrode 46, 47 is electrically connected to the second through conductor 45. Each of the terminal electrodes 46 and 47 has a circular shape in a plan view, and has an outer diameter (150 μm in this embodiment) larger than the maximum diameter (100 μm) of the second through conductor 45. Moreover, the thickness of each terminal electrode 46 and 47 in this embodiment is set to 10 micrometers.

  Furthermore, the second substrate back surface 42 of the second glass substrate 40 is almost entirely covered with a solder resist layer 61 made of epoxy resin and having a thickness of about 30 μm. An opening 62 for exposing the back-side terminal electrode 47 is formed at a predetermined position of the solder resist layer 61. A plurality of solder bumps 63 are provided on the surface of the back-side terminal electrode 47 for electrical connection with a mother board (not shown).

  As shown in FIG. 1, a second stress relaxation layer mainly composed of a resin insulating material (cycloolefin resin) to which an inorganic filler (silica filler) is added is provided between the second glass substrate 40 and the wiring laminated portion 11. 82 is formed. That is, the second stress relaxation layer 82 is formed of the same material as the resin insulating layers 21 to 23 and the first stress relaxation layer 81. The Young's modulus of the second stress relaxation layer 82 is that of the glass substrates 30 and 40 (73 GPa), the Young's modulus of the through conductors 35 and 45 (118 GPa), and the Young's modulus of the resin insulating layers 21 to 23 (8 GPa). ) And equal to the Young's modulus of the first stress relaxation layer 81, which is 2 GPa in this embodiment. Further, the content of the inorganic filler in the second stress relaxation layer 82 is smaller than the content (about 45% by volume) of the inorganic filler in the resin insulating layers 21 to 23 and equal to the content of the first stress relaxation layer 81. In this embodiment, it is 30% by volume. The second stress relaxation layer 82 has a substantially rectangular plate shape of 20 mm long × 20 mm wide × 5 μm thick.

  Further, the second stress relaxation layer 82 is formed with a plurality of second through holes 84 penetrating the second stress relaxation layer 82 in the thickness direction. Each of the second through holes 84 has a circular shape in plan view, and has a tapered shape in which the inner diameter gradually decreases toward the second substrate main surface 41 side. In the second through hole 84 of the present embodiment, the inner diameter of the opening on the second substrate main surface 41 side is set to 60 μm, and the inner diameter of the opening on the back surface 13 side of the laminated portion is set to 65 μm. In the second through hole 84, one end portion (the upper end portion in FIG. 1) of the second through conductor 45 is disposed.

  Next, the manufacturing method of the wiring board 10 of this embodiment is demonstrated.

  First, in the first glass substrate preparation step, a pair of first glass substrates 30 on which the first stress relaxation layer 81 is formed on the first substrate back surface 32 is prepared by a conventionally known technique and prepared in advance. The first glass substrate 30 is produced as follows. First, a commercially available thin glass substrate (OA-10G manufactured by Nippon Electric Glass Co., Ltd.) is prepared. The thin glass substrate has a rectangular plate shape of 150 mm long × 150 mm wide × 0.2 mm thick (= 200 μm). The thin glass substrate is a first multi-cavity glass substrate in which a plurality of substrate formation regions to be the first glass substrate 30 are arranged vertically and horizontally along the planar direction. Moreover, the 1st stress relaxation layer 81 is formed in the glass substrate lamination process mentioned later.

  In the second glass substrate preparation step, a pair of second glass substrates 40 in which the second stress relaxation layer 82 is formed on the second substrate main surface 41 is prepared by a conventionally known method and prepared in advance ( (See FIG. 2). The second glass substrate 40 is produced as follows. First, the same thin glass substrate as the thin glass substrate used for the production of the first glass substrate 30 is prepared. The thin glass substrate prepared here is a second multi-piece glass substrate in which a plurality of substrate forming regions to be the second glass substrate 40 are arranged vertically and horizontally along the plane direction. Next, a coupling process is performed on the entire second substrate main surface 41 using a conventionally known silane coupling agent (for example, manufactured by Shin-Etsu Chemical Co., Ltd.). Further, a second resin sheet to be an uncured second stress relaxation layer 82 is laminated on the second substrate main surface 41 subjected to the coupling process. In addition, the 2nd resin sheet of this embodiment consists of a resin material (in this embodiment, cycloolefin resin) excellent in heat resistance, and has comprised the rectangular plate shape of 150 mm long x 150 mm wide x 5 micrometers in thickness. Thereafter, when heat treatment (curing) is performed for a predetermined time, the second resin sheet is cured and becomes the second stress relaxation layer 82 (see FIG. 2).

  Next, the second glass substrate 40 (the first glass substrate 40 (the first not shown) is directed to the second substrate back surface 42 opposite to the second substrate main surface 41 on which the second stress relaxation layer 82 is formed. A laser (in this embodiment, a carbon dioxide gas laser) is irradiated to a glass plate for two multi-pieces. As a result, a large number of second through holes 44 are formed through the second glass substrate 40, and a large number of second through holes 84 are formed through the second stress relaxation layer 82 (see FIG. 2). In addition, by directly irradiating the second substrate back surface 42 with laser, absorption of laser light toward the second substrate back surface 42 side of the second glass substrate 40 is promoted. As a result, the second through hole 44 is formed to have a taper shape in which the inner diameter gradually increases toward the second substrate back surface 42 side. Furthermore, absorption of laser light is promoted to the second stress relaxation layer 82 having a higher laser absorption rate than the second glass substrate 40. As a result, the second through hole 84 is formed to have a tapered shape in which the inner diameter gradually decreases toward the second substrate main surface 41 side.

  Further, sputtering of titanium is performed from the second substrate main surface 41 side (second stress relaxation layer 82 side) to form a titanium layer (seed layer) having a thickness of 0.1 μm, and the surface 85 of the second stress relaxation layer 82 is formed. The titanium layer formed on the inner surface of the second through hole 44 on the second substrate main surface 41 side is a continuous layer without being divided. Further, a titanium layer is formed by sputtering titanium from the second substrate back surface 42 side, and the titanium layer formed on the second substrate back surface 42 and the inner surface of the second through hole 44 on the second substrate back surface 42 side are formed. The formed titanium layer is a continuous layer without being divided. Further, copper is sputtered from the second substrate main surface 41 side and the second substrate back surface 42 side to form a copper layer (seed layer) having a thickness of 0.8 μm on the titanium layer.

  Next, the surface of the copper layer formed on the inner surface of the second through-hole 44, the surface of the copper layer formed on the surface 85 of the second stress relaxation layer 82, and the copper formed on the back surface 42 of the second substrate Electrolytic copper plating is performed on the surface of each layer. At this point, the second through conductor 45 is formed in the second through hole 44 and the second through hole 84, a solid pattern covering the entire surface 85 is formed, and a solid pattern covering the entire second substrate back surface 42 is formed. Is formed. Thereafter, patterning is performed by a subtractive method. Specifically, a dry film is laminated on the second substrate main surface 41 and the second substrate back surface 42, and an etching resist having a predetermined pattern is formed by exposing and developing the dry film. In this state, patterning by etching is performed on the solid pattern on the front surface 85 side and the second substrate back surface 42 side. At this point, the main surface side terminal electrode 46 is formed on the front surface 85 and the back surface side terminal electrode 47 is formed on the second substrate back surface 42 (see FIG. 2). Thereafter, the etching resist is peeled off.

  In addition, you may form the main surface side terminal electrode 46 and the back surface side terminal electrode 47 by another method. More specifically, a dry film is laminated on the surface of the copper layer formed on the surface 85 of the second stress relaxation layer 82 and the surface of the copper layer formed on the back surface 42 of the second substrate, respectively. (Not shown) is formed. Next, after patterning by photolithography, the surface of the copper layer formed on the inner surface of the second through hole 44, the surface of the copper layer formed on the surface 85, and the back surface of the second substrate 42 are formed. Electrolytic copper plating is performed on the surface of each copper layer. At this time, the second through conductor 45 is formed in the second through hole 44 and the second through hole 84, the main surface side terminal electrode 46 is formed on the front surface 85, and the second substrate back surface 42 is formed. A back-side terminal electrode 47 is formed (see FIG. 2). Thereafter, the plating resist is peeled off, and the titanium layer and the copper layer protected by the plating resist are removed by etching.

  Further, a base material preparation step is performed to prepare a support base material 91 in advance (see FIG. 3). In addition, the support base material 91 of this embodiment has the base material main surface 92, the base material back surface 93, and the base material side surface 94, and sticks the peeling sheet 96 on the main surface center part and back surface center part of the adhesive sheet 95. It is constituted by. The adhesive sheet 95 has a substantially rectangular plate shape with a length of 150 mm × width of 150 mm × thickness of 250 μm, and the central portion of the adhesive sheet 95 is thinned by being pressed by the release sheet 96. The release sheet 96 has a substantially rectangular plate shape with a length of 145 mm, a width of 145 mm, and a thickness of 50 μm. In this embodiment, the outer peripheral portion of the adhesive sheet 95 becomes the adhesive portion 97 disposed on the outer peripheral portion of the support base material 91, and the release sheet 96 is disposed on the inner side of the adhesive portion 97 in the support base material 91. It becomes the peeling part 98 which becomes. The adhesive portion 97 is exposed on the base material main surface 92, the base material back surface 93, and the base material side surface 94 of the support base material 91. The main surface and the back surface of the adhesive sheet 95 are flush with the outer surface of the release sheet 96 in the formation region of the adhesive portion 97. In addition, as the adhesive sheet 95 (adhesion part 97) of this embodiment, the double-sided adhesive type tape which consists of a material which has photoreleasability (for example, SELFA by Sekisui Chemical Co., Ltd., UV release type by Denka Adtex Co., Ltd. Dicing tape etc.) are used. Further, the release sheet 96 (peeling portion 98) is made of a resin material (polyethylene terephthalate resin in the present embodiment) having lower adhesiveness than the adhesive portion 97 and higher heat resistance than the resin insulating layers 21 to 23. A resin sheet is used.

  And a sticking process is performed after a 1st glass substrate preparation process, a 2nd glass substrate preparation process, and a base material preparation process. Specifically, first, a pair of second glass substrates 40 is prepared, and each second substrate main surface 41 is directed to the opposite side, and each second substrate back surface 42 is disposed facing each other. To do. At this time, the supporting base material 91 is interposed between the second substrate back surfaces 42 of the second glass substrates 40 arranged to face each other. As a result, the second glass substrate 40 is disposed on both the base material main surface 92 and the base material back surface 93 of the support base material 91. Next, a predetermined pressure is applied to the laminated body composed of the two second glass substrates 40 and the single supporting base material 91 in the thickness direction and pressed. As a result, the bonding portion 97 is temporarily bonded to the outer peripheral portion of the second substrate back surface 42, and the peeling portion 98 is in contact with the center portion of the second substrate back surface 42, so that the pair of second glass substrates 40 are supported on the support base. They are temporarily bonded to each other through the material 91 (bonding portion 97) (see FIG. 3).

  In the wiring laminated portion forming step after the pasting step, the wiring laminated portion 11 is formed on the second stress relaxation layer 82 formed on the second substrate main surface 41 based on a conventionally known method (see FIG. 4). ). Specifically, first, a 20 μm-thick cycloolefin resin film (ZS-100, manufactured by Nippon Zeon Co., Ltd.) is deposited on the second stress relaxation layer 82 of each second glass substrate 40 ( By sticking), the resin insulating layer 21 is formed.

  Further, laser drilling is performed using a YAG laser or a carbon dioxide gas laser to form a via hole at a position where the via conductor 27 is to be formed. Specifically, a via hole penetrating the resin insulating layer 21 is formed, and the surface of the main surface side terminal electrode 46 is exposed. Next, electrolytic copper plating is performed according to a conventionally known method to form a via conductor 27 inside the via hole and to form a metal wiring layer 24 on the resin insulating layer 21.

  Next, a second resin insulation layer 22 is formed by depositing a resin film on the first resin insulation layer 21. Further, laser drilling is performed using a YAG laser or a carbon dioxide gas laser, and via holes are formed in the resin insulating layer 22 at positions where the via conductors 27 are to be formed. Next, electrolytic copper plating is performed in accordance with a conventionally known method to form a via conductor 27 inside the via hole and to form a metal wiring layer 25 on the resin insulating layer 22.

  Next, a third resin insulating layer 23 is formed by depositing a resin film on the second resin insulating layer 22. Further, laser drilling is performed using a YAG laser or a carbon dioxide gas laser, and via holes are formed in the resin insulating layer 23 at positions where the via conductors 27 are to be formed. Next, electrolytic copper plating is performed in accordance with a conventionally known method to form a via conductor 27 in the via hole and a metal wiring layer 26 on the resin insulating layer 23. At this point, the wiring laminated portion 11 shown in FIG. 4 is completed.

  In the glass substrate laminating step after the wiring laminating portion forming step, first, the first glass substrate 30 is used by using the same silane coupling agent as that used in the coupling process for the second substrate main surface 41 of the second glass substrate 40. A coupling process is performed on the entire first substrate back surface 32. Next, the 1st resin sheet used as the 1st stress relaxation layer 81 of the unhardened state is laminated on the lamination part main surface 12 of the wiring lamination part 11. In addition, the 1st resin sheet of this embodiment consists of the same resin material (cycloolefin resin) as the 2nd resin sheet used as the 2nd stress relaxation layer 82, and is a rectangular plate shape of length 150mm * width 150mm * thickness 5micrometer. There is no. Thereafter, when heat treatment (curing) is performed for a predetermined time, the first resin sheet is cured and becomes the first stress relaxation layer 81 (see FIG. 5).

  Further, the first substrate back surface 32 subjected to the coupling process is directed to the wiring laminated portion 11 side (first stress relaxing layer 81 side), and the first stress relaxing layer 81 is interposed on the wiring laminated portion 11. The first glass substrate 30 is stacked (see FIG. 5). Then, a pressing force (0.2 MPa) is applied in the laminating direction while heating so that the temperature becomes 110 ° C. (hot pressing). Along with this, the wiring laminated portion 11, the first stress relaxation layer 81, and the first glass substrate 30 are pressed along the lamination direction, and the viscosity of the organic material in the first stress relaxation layer 81 is increased by heat. As a result, the first stress relaxation layer 81 and the first glass substrate 30 are bonded (thermocompression bonding) on the wiring laminated portion 11.

  Next, in a state where the laser irradiation device (not shown) is directed to the first substrate main surface 31 opposite to the first substrate back surface 32 on which the first stress relaxation layer 81 is formed, the first glass substrate 30 (first A laser (in this embodiment, a carbon dioxide gas laser) is irradiated to a single glass substrate. As a result, a large number of first through holes 34 are formed through the first glass substrate 30, and a plurality of first through holes 83 are formed through the first stress relaxation layer 81 (see FIG. 6). Further, by directly irradiating the first substrate main surface 31 with the laser, absorption of laser light toward the first substrate main surface 31 side of the first glass substrate 30 is promoted. As a result, the first through hole 34 is formed to have a tapered shape with the inner diameter gradually increasing toward the first substrate main surface 31 side. Furthermore, absorption of laser light is promoted to the first stress relaxation layer 81 having a higher laser absorption rate than the first glass substrate 30. As a result, the first through hole 83 is formed to have a taper shape with the inner diameter gradually decreasing toward the first substrate back surface 32 side.

  Further, titanium is sputtered from the first substrate main surface 31 side to form a titanium layer (seed layer) having a thickness of 0.1 μm. The titanium layer formed on the first substrate main surface 31 and the first through hole The titanium layer formed on the inner surface of 34 is a continuous layer without being divided. Further, copper is sputtered from the first substrate main surface 31 side to form a 0.8 μm thick copper layer (seed layer) on the titanium layer.

  Next, electrolytic copper plating is performed on the surface of the copper layer formed on the inner side surface of the first through hole 34 and the surface of the copper layer formed on the first substrate main surface 31. At this time, the first through conductor 35 is formed in the first through hole 34, and a solid pattern covering the entire first substrate main surface 31 is formed. Thereafter, patterning is performed by a subtractive method. Specifically, a dry film is laminated on the first substrate main surface 31, and an etching resist having a predetermined pattern is formed by performing exposure and development on the dry film. In this state, the solid pattern is patterned by etching. At this point, the main surface side terminal electrode 36 is formed on the first substrate main surface 31 (see FIG. 7). Thereafter, the etching resist is peeled off.

  The main surface side terminal electrode 36 may be formed by another method. More specifically, a dry film is laminated on the surface of the copper layer formed on the first substrate main surface 31 to form a plating resist (not shown). Next, after patterning by photolithography, the surface of the copper layer formed on the inner surface of the first through hole 34 and the surface of the copper layer formed on the first substrate main surface 31 are electrolyzed. Perform copper plating. At this time, the first through conductor 35 is formed in the first through hole 34 and the first through hole 83, and the main surface side terminal electrode 36 is formed on the first substrate main surface 31 (see FIG. 7). . Thereafter, the plating resist is peeled off, and the titanium layer and the copper layer protected by the plating resist are removed by etching.

  After the glass substrate lamination step, a separation step is performed, and ultraviolet light (UV light) is irradiated to the bonding portion 97 (see FIG. 8). More specifically, in the separation step, the substrate side surface 94 is irradiated with ultraviolet light from the side of the support substrate 91. As a result, the second glass substrate 40 and the support base 91 are separated at the interface between the second glass substrate 40 and the bonding portion 97, and the pair of second glass substrates 40 temporarily bonded via the bonding portion 97 are mutually connected. To be separated. As a result, the second substrate back surface 42 hidden in the inner layer is exposed.

  After the separation step, the solder resist layer 51 is formed by applying and curing a photosensitive epoxy resin on the first substrate main surface 31. Also, a solder resist layer 61 is formed by applying and curing a photosensitive epoxy resin on the second substrate back surface 42. Next, exposure and development are performed in a state in which a predetermined mask is arranged to form an opening 52 in the solder resist layer 51 and an opening 62 in the solder resist layer 61. In addition, it can be grasped that the product in this state is a multi-cavity wiring board in which a plurality of product regions to be the wiring board 10 are arranged vertically and horizontally along a plane.

  Further, a solder paste is printed on the main surface side terminal electrode 36 formed on the first substrate main surface 31. Also, a solder paste is printed on the back-side terminal electrode 47 formed on the second substrate back surface 42. Next, the multi-piece wiring board on which the solder paste is printed is placed in a reflow furnace and heated to a temperature 10 to 40 ° C. higher than the melting point of the solder. At this time, the solder paste is melted to form the solder bumps 53 for mounting the IC chip 71 in a hemispherical shape, and the solder bumps 63 for mounting the motherboard in the same hemispherical shape are formed. The

  Furthermore, the multi-piece wiring substrate is cut along the outline of the substrate forming region using a conventionally known cutting device (laser processing machine, dicing device or the like). In this embodiment, using a dicing blade (ZBT-4991 manufactured by DISCO Corporation) having an outer diameter of 51.4 mm, an inner diameter of 40 mm, and a blade thickness of 0.03 mm, cutting is performed under conditions of a processing speed of 1 mm / s and a rotational speed of 30000 rpm. Do. As a result, the substrate formation regions are divided, and a plurality of wiring substrates 10 shown in FIG. 1 are obtained simultaneously.

  Thereafter, the IC chip 71 is placed on the surface of the first glass substrate 30 constituting the wiring substrate 10. At this time, the surface connection terminals 72 on the IC chip 71 side and the solder bumps 53 are aligned. Then, each solder bump 53 is reflowed by heating to a temperature of about 220 to 240 ° C., thereby joining each solder bump 53 and the surface connection terminal 72 to electrically connect the wiring substrate 10 side and the IC chip 71 side. Connect to. As a result, the IC chip 71 is mounted on the wiring board 10.

  Next, a method for evaluating a wiring board and the result will be described.

  First, a measurement sample was prepared as follows. A wiring board substantially the same as the wiring board 10 of this embodiment was prepared, and this was taken as Example 1. In addition, seven types of wiring boards obtained by changing the pitch of the through conductors, the taper ratio of the through conductors (outer diameter of the through conductors), the thickness of the stress relaxation layer, and the like were prepared. It was set to ~ 8. In Examples 1 to 8, the through conductor provided in the upper first glass substrate has a tapered shape ("▼" in Table 1) in which the outer diameter gradually increases toward the upper side (the outer layer side in the wiring substrate). And the through conductor provided in the lower second glass substrate was tapered (“▲” in Table 1) with the outer diameter gradually increasing toward the lower side (outer layer side in the wiring substrate). In Examples 3 and 4, the volume ratio and taper ratio of the through conductors of the second glass substrate were made larger than those of the first glass substrate. Further, in Examples 5 and 6, the thickness of the stress relaxation layer formed between the first glass substrate having the higher volume ratio of the through conductor and the wiring laminated portion is set to the second glass having the lower volume ratio. The thickness was larger than the thickness of the stress relaxation layer formed between the substrate and the wiring laminate. Further, in Example 7, the taper ratio of the through conductor in the second glass substrate having the higher volume ratio of the through conductor was made smaller than the taper ratio of the through conductor in the first glass substrate having the lower volume ratio. In Example 8, the taper ratio of the through conductor in the first glass substrate with the higher volume ratio of the through conductor was made smaller than the taper ratio of the through conductor in the second glass substrate with the lower volume ratio.

  On the other hand, a wiring board in which three resin insulating layers were laminated on both sides of a glass substrate with a through conductor (first glass substrate) was prepared. In addition, two types of through conductors provided on the lower second glass substrate are tapered ("▼" in Table 1) in which the outer diameter gradually decreases toward the lower side (outer layer side of the wiring substrate). The wiring boards were prepared as Comparative Examples 2 and 3, respectively. The through conductors in Comparative Examples 2 and 3 were changed by changing the laser irradiation surface from the back surface of the second glass substrate to the main surface.

  In addition, 25 measurement samples were prepared for each. Further, in the measurement sample, the formation of the solder resist layer and the solder bump, which are assumed not to affect the evaluation result, was omitted.

  Next, with respect to each measurement sample (Examples 1 to 8, Comparative Examples 1 to 3), the maximum warpage amount of the wiring board was measured by non-contact measurement using a laser. As a result, the case where the maximum warpage amount was 100 μm or less was determined as “pass”. A sample for measurement in which “pass” is determined to be 90% or more (yield 90% or more) is determined to be “◎”, and “pass” is determined to be 80% or more (yield 80% or more). ) Was determined to be “◯”, and samples for which “pass” was determined to be 70% or more (yield 70% or more) were determined to be “Δ”. In addition, a sample for measurement in which “pass” was determined to be less than 70% (yield less than 70%) was determined to be “x”. The results are shown in Table 1.

Further, each measurement sample was visually observed with a microscope, and it was observed whether or not cracks occurred at the end portions (side surfaces) of the glass substrates (first glass substrate and second glass substrate). Here, the occurrence of cracks was judged visually, and those that could not be confirmed visually were judged as “pass”. In this case as well, a measurement sample that is determined to be “pass” is 90% or more is determined as “「 ”, and a measurement sample that is determined as“ pass ”is 80% or more. A sample for measurement in which 70% or more was determined as “pass” was determined as “Δ”. Moreover, the sample for measurement in which what is determined as “pass” is less than 70% is determined as “x”. The results are shown in Table 1.

  As a result, in Comparative Example 1, it was confirmed that many cracks occurred on the side surface of the glass substrate. In Comparative Example 1, since too many cracks occurred, the amount of warpage of the wiring board could not be evaluated. In Comparative Examples 2 and 3, the cracks hardly occurred, but the direction of the through conductor of the first glass substrate and the through conductor of the second glass substrate was the same, and the wiring board was often warped. Was confirmed.

  On the other hand, in Examples 1-8, the generation | occurrence | production of the curvature of a wiring board and the generation | occurrence | production of the crack by the side surface of a glass substrate were hardly confirmed. In particular, in Examples 5 and 6, it was confirmed that warping of the wiring board is less likely to occur. However, in Examples 7 and 8, it was confirmed that the wiring board was slightly warped.

  From the above, if a wiring substrate in which the first glass substrate and the second glass substrate are respectively arranged on both sides of the wiring laminated portion made of a plurality of resin insulating layers is formed, the stress is applied to the first glass substrate and the second glass substrate. Therefore, it is proved that the side surface of the glass substrate is hardly cracked and the yield of the wiring substrate is increased. Further, in both the first glass substrate and the second glass substrate, if the through conductor has a tapered shape in which the outer diameter gradually increases toward the outer layer side of the wiring substrate, the wiring substrate is less likely to warp. It was proved that the yield of the wiring board was high. Furthermore, if the stress relaxation layer is made thicker or the taper ratio of the through conductor in the glass substrate with the higher volume ratio of the through conductor is made larger than the taper ratio of the through conductor in the glass substrate with the lower volume ratio. It has been proved that the warpage of the wiring board is less likely to occur.

  Therefore, according to the present embodiment, the following effects can be obtained.

  (1) According to the wiring substrate 10 of the present embodiment, the wiring laminated portion 11 is disposed in the inner layer portion of the wiring substrate 10, and the glass substrates 30 and 40 are disposed in the outer layer portion of the wiring substrate 10. , 40 and the wiring laminated portion 11 are dispersed in the first glass substrate 30 and the second glass substrate 40 due to the difference in thermal expansion. As a result, concentration of thermal stress on the substrate side surfaces 33 and 43 of the glass substrates 30 and 40 is prevented, so that breakage of the glass substrates 30 and 40 can be prevented. Moreover, since the stress relaxation layers 81 and 82 are formed between the first glass substrate 30 and the wiring laminated portion 11 and between the second glass substrate 40 and the wiring laminated portion 11, respectively, the glass substrate 30, Concentration of thermal stress due to the difference in thermal expansion between the wiring layer 40 and the wiring laminated portion 11 is reliably relaxed by the stress relaxation layers 81 and 82. Further, in both the first glass substrate 30 and the second glass substrate 40, the through conductors 35 and 45 have a tapered shape that gradually increases toward the outer layer side in the wiring substrate 10, and thus the through conductors 35 and 45 The stress applied to the glass substrates 30 and 40 during the formation of 45 is surely relieved. Therefore, breakage and warping of the glass substrates 30 and 40 can be reliably prevented. From the above, since it is difficult for the glass substrates 30 and 40 to be defective, the yield of the wiring substrate 10 can be improved, and the reliability of the wiring substrate 10 is improved.

  (2) The conventional technique described in Patent Document 2 includes a technique in which an inorganic insulating layer is laminated on each of the main surface and the back surface of a resin layer, and a through conductor that penetrates the inorganic insulating layers on the main surface side and the back surface side is formed. It is disclosed. However, since the pitch between adjacent through conductors is the same in both the inorganic insulating layer on the main surface side and the inorganic insulating layer on the back surface side, the degree of freedom of wiring can be reduced and the density can be increased. There is a problem that you can not. On the other hand, in the present embodiment, the pitch between the adjacent through conductors 35 and 45 is different between the first glass substrate 30 and the second glass substrate 40. For this reason, the freedom degree of the wiring provided in the wiring board 10 becomes large, and the density of wiring can be achieved.

  (3) Since the 2nd glass substrate 40 of this embodiment is a comparatively thin glass substrate (thickness 200 micrometers), intensity | strength increases by bonding the support base material 91 in a sticking process, and handling property improves.

  (4) The IC chip 71 of the present embodiment is disposed directly above the wiring laminated portion 11 and the glass substrates 30 and 40. As a result, the conduction path for electrically connecting the IC chip 71 to the wiring laminated portion 11 and the glass substrates 30 and 40 is the shortest. Therefore, the power supply to the IC chip 71 can be performed smoothly. In addition, since noise entering between the IC chip 71, the wiring laminated portion 11 and the glass substrates 30 and 40 can be suppressed to an extremely low level, high reliability can be obtained without causing malfunction such as malfunction. .

  The IC chip 71 is supported by the first glass substrate 30 that is highly rigid, has a smaller thermal expansion coefficient than the resin insulating layers 21 to 23, and has a thermal expansion coefficient close to that of the IC chip 71. Therefore, since the first glass substrate 30 is difficult to deform, the IC chip 71 mounted on the first glass substrate 30 can be supported more stably. Therefore, it is possible to prevent the IC chip 71 from cracking or poor connection due to large thermal stress. Therefore, as the IC chip 71, a large IC chip of 10 mm square or more, which is affected by thermal stress due to a difference in thermal expansion and has a large influence of thermal stress, and has a large heat generation and severe thermal shock during use, is considered to be brittle. A low-k (low dielectric constant) IC chip can be used.

  In addition, you may change this embodiment as follows.

  -Although the 1st stress relaxation layer 81 of the said embodiment was formed on the lamination | stacking part main surface 12 of the wiring lamination | stacking part 11 after a wiring lamination | stacking part formation process, in the 1st glass substrate preparation process, it is 1st glass. It may be formed on the first substrate back surface 32 of the substrate 30. Moreover, although the 2nd stress relaxation layer 82 of the said embodiment was formed on the 2nd board | substrate main surface 41 of the 2nd glass substrate 40 in the 2nd glass substrate preparation process, It may be formed on the laminated part back surface 13 of the wiring laminated part 11.

  In the above embodiment, the thickness of the first stress relaxation layer 81 and the thickness of the second stress relaxation layer 82 are equal to each other, but may be different from each other. For example, the thickness of the first stress relaxation layer 81 formed between the first glass substrate 30 having the higher volume ratio of the through conductor and the wiring laminated portion 11 is set to the second glass substrate 40 having the lower volume ratio. And the thickness of the second stress relaxation layer 82 formed between the wiring laminated portion 11 and the wiring laminated portion 11 may be larger.

  In the above embodiment, the thickness of the first glass substrate 30 and the thickness of the second glass substrate 40 are different from each other, but may be equal to each other.

  In the pasting step of the above embodiment, the pair of second glass substrates 40 are temporarily bonded to each other via the support base 91, but both the second glasses are bonded using a heat-peelable or ultraviolet-peelable adhesive. The substrate 40 may be temporarily bonded.

  Next, the technical ideas grasped by the embodiment described above are listed below.

  (1) The wiring board according to the above means 1, wherein the thickness of the first glass substrate and the thickness of the second glass substrate are different from each other.

  (2) In the above means 1, the wiring board is characterized in that a taper ratio of the through conductor is 0.01 or more and 0.5 or less.

DESCRIPTION OF SYMBOLS 10 ... Wiring board 11 ... Wiring laminated part 12 ... Laminated part main surface 13 ... Laminated part back surface 21,22,23 ... Resin insulation layers 24, 25, 26 ... Metal wiring layer 30 ... 1st glass substrate 31 ... 1st board | substrate main Surface 32... First substrate back surface 35... First through conductor 40 as through conductor. Second glass substrate 41. Second substrate main surface 42. Second substrate back surface 45. Second through conductor 71 as through conductor. IC chip 73 as an IC chip mounting region 81 as a semiconductor chip mounting region, a first stress relaxation layer 82 as a stress relaxation layer, a second stress relaxation layer 97 as a stress relaxation layer, an adhesion portion

Claims (8)

A wiring laminated portion having a structure in which a laminated portion main surface and a laminated portion back surface are laminated, and a plurality of resin insulation layers and a plurality of metal wiring layers are laminated;
A first glass substrate formed on the main surface side of the laminated portion and having a first substrate main surface and a first substrate back surface;
A wiring substrate comprising a second glass substrate having a second substrate main surface and a second substrate back surface, which is formed on the back side of the laminated portion;
The first glass substrate is provided with a through conductor that electrically connects the first substrate main surface side and the first substrate back surface side and is electrically connected to the metal wiring layer,
The second glass substrate is provided with a through conductor that electrically connects the second substrate main surface side and the second substrate back surface side and is electrically connected to the metal wiring layer,
A stress relaxation layer is formed between the first glass substrate and the wiring laminated portion and between the second glass substrate and the wiring laminated portion,
In any of the first glass substrate and the second glass substrate, the through conductor has a tapered shape in which the outer diameter gradually increases toward the outer layer side of the wiring substrate. .   Of the first glass substrate and the second glass substrate, the taper ratio of the through conductor in the glass substrate having a higher volume ratio of the through conductor in the glass substrate is the glass substrate in the lower volume ratio. The wiring board according to claim 1, wherein the wiring board has a taper ratio larger than that of the through conductor.   Of the first glass substrate and the second glass substrate, the thickness of the stress relaxation layer formed between the glass substrate having a higher volume ratio of the through conductor in the glass substrate and the wiring laminate portion is The wiring board according to claim 1, wherein a thickness of the stress relaxation layer formed between the glass substrate having the lower volume ratio and the wiring laminated portion is larger.   The number of the through conductors and the minimum value of the pitch between the adjacent through conductors are different between the first glass substrate and the second glass substrate. Wiring board as described in.   A semiconductor chip is mounted on a semiconductor chip mounting region set in a glass substrate having a smaller minimum pitch between adjacent through conductors of the first glass substrate and the second glass substrate. The wiring board according to any one of claims 1 to 4.   6. The wiring board according to claim 1, wherein the content of the inorganic filler in the stress relaxation layer is smaller than the content of the inorganic filler in the resin insulating layer.   The wiring substrate according to claim 1, wherein the through conductor is made of copper. It is a manufacturing method of the wiring board according to any one of claims 1 to 7,
A first glass substrate preparation step of preparing at least a pair of the first glass substrates;
A second glass substrate preparation step of preparing at least a pair of the second glass substrates in which the stress relaxation layer mainly composed of a resin insulating material is formed on the second substrate main surface;
After the second glass substrate preparation step, the pair of second glass substrates are temporarily bonded to each other through the bonding portion in a state where the second substrate main surfaces of the pair of second glass substrates are directed to opposite sides. Pasting process,
After the pasting step, a wiring laminated portion forming step of forming the wiring laminated portion on the stress relaxation layer formed on the second substrate main surface;
After the wiring laminated portion forming step, a glass substrate laminating step of laminating the first glass substrate on the wiring laminated portion via the stress relaxation layer,
And a separating step of separating the pair of second glass substrates temporarily bonded via the bonding portion after the glass substrate laminating step.

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