Search

EP-3846597-B1 - WIRING BOARD AND ELECTRONIC DEVICE

EP3846597B1EP 3846597 B1EP3846597 B1EP 3846597B1EP-3846597-B1

Inventors

  • ITOU,Seiichirou
  • ISHIZAKI,Yuichiro
  • KAWAMURA,Genshitaro

Dates

Publication Date
20260506
Application Date
20190827

Claims (11)

  1. A wiring substrate (1), comprising: an insulating substrate (11) comprising a principal face (11a); a wiring line (12) located on the principal face (11a); and a protruding portion (12a) on a side of the wiring line (12), the protruding portion (12a) being smaller in thickness than the wiring line (12) and protruding from the side along the principal face (11a); characterized by a resistor layer (4) located on the insulating substrate (11) and the wiring line (12), the resistor layer (4) being located so as to extend from an upper surface of the wiring line (12) over the side of the wiring line (12) and the protruding portion (12a) onto the principal face (11a) of the insulating substrate.
  2. The wiring substrate (1) according to claim 1, wherein the wiring line (12) comprises at the side an inclined portion (12b), the inclined portion (12b) inclined toward the protruding portion (12a) and connected to the protruding portion (12a).
  3. The wiring substrate (1) according to claim 1 or 2, wherein the wiring line (12) comprises an adherent layer (12ca), a barrier layer (12cb), and a principal conductor layer (12cc), which are arranged, in multi-layer form, in an order from the principal face (11a) of the insulating substrate (11); and the protruding portion (12a) comprises a part of the principal conductor layer (12cc).
  4. The wiring substrate (1) according to claim 3, wherein the protruding portion (12a) comprises a part of the barrier layer (12cb) located between the principal conductor layer (12cc) of the protruding portion (12a) and the principal face (11a) of the insulating substrate (11).
  5. The wiring substrate (1) according to claim 4, wherein the protruding portion (12a) comprises a part of the adherent layer (12ca) located between the part of the barrier layer (12cb) of the protruding portion (12a) and the principal face (11a) of the insulating substrate (11).
  6. The wiring substrate (1) according to any one of claims 3 to 5, wherein, in a vertical sectional view of the wiring substrate (1), a part of the principal conductor layer (12cc) is located on a side of the barrier layer (12cb).
  7. The wiring substrate (1) according to any one of claims 3 to 6, wherein, in a vertical sectional view of the wiring substrate (1), a part of the barrier layer (12cb) and a part of the principal conductor layer (12cc) are located on a side of the adherent layer (12ca) and are arranged in that order from the side of the adherent layer (12ca).
  8. The wiring substrate (1) according to any one of claims 3 to 7, wherein a part of the principal conductor layer (12cc) continuously extends along the side of the wiring line (12) and further along the protruding portion (12a).
  9. The wiring substrate (1) according to any one of claims 3 to 8, wherein a part of the barrier layer (12cb) continuously extends along the side of the wiring line (12) and further along the protruding portion (12a).
  10. The wiring substrate (1) according to any one of claims 3 to 9, wherein a part of the adherent layer (12ca) continuously extends along the side of the wiring line (12) and further along the protruding portion (12a).
  11. An electronic device, comprising: a wiring substrate (1) according to any one of claims 1 to 10; and an electronic component (2) mounted on the wiring substrate (1).

Description

Technical Field The present invention relates to a wiring substrate and an electronic device. Background Art Heretofore a wiring substrate including an insulating substrate with a wiring line located thereon, an electronic component-mounted electronic device, etc. are known (refer to JP-A 2001-102722, JP-A 2006-108126, JP-A 2000-299202, JP-A H05 109925 and US 2010/193225 A1, for example). Summary of Invention Solution to Problem A wiring substrate according to the present disclosure includes: an insulating substrate including a principal face; a wiring line located on the principal face; and a protruding portion on a side of the wiring line, the protruding portion being smaller in thickness than the wiring line and protrudes from the side along the principal face. A resistor layer is located on the insulating substrate and the wiring line, the resistor layer being located so as to extend from an upper surface of the wiring line over the side of the wiring line and the protruding portion onto the principal face of the insulating substrate. An electronic device according to the disclosure includes: the wiring substrate described above; and an electronic component mounted on the wiring substrate. Brief Description of Drawings FIG. 1 is a vertical sectional view showing an electronic device according to an embodiment of the invention;FIG. 2 is an enlarged view of main parts in Part A shown in FIG. 1;FIG. 3 is an enlarged view of main parts in Part B shown in FIG. 2;FIG. 4 is a main-part enlarged view showing another example of the electronic device according to the embodiment;FIG. 5 is a main-part enlarged view, corresponding to Part A shown in FIG. 1, showing still another example of the electronic device according to the embodiment;FIG. 6 is an enlarged view of main parts in Part B shown in FIG. 5;FIG. 7 is a main-part enlarged view showing still another example of the electronic device according to the embodiment; andFIG. 8 is a main-part enlarged view showing still another example of the electronic device according to the embodiment. Description of Embodiments Exemplary embodiments of the disclosure will now be described with reference to the accompanying drawings. Referring to FIGS. 1 to 8, an electronic device according to an embodiment of the disclosure will be described. The electronic device according to this embodiment includes: a wiring substrate 1; a resistor layer 4; and an electronic component 2. In this embodiment, for example, the wiring substrate 1 includes: an insulating substrate 11 including a principal face 11a; and a wiring line (a thin-film wiring line, for instance) 12 located on the principal face 11a. The insulating substrate 11 may be made of ceramics, e.g. an aluminum oxide sintered body (alumina ceramics), an aluminum nitride sintered body, a mullite sintered body, or a glass ceramics sintered body. In the case where the insulating substrate 11 is made of a resin material, for example, it is possible to use epoxy resin, polyimide resin, acrylic resin, phenol resin, polyester resin, and fluorine resin typified by tetrafluoroethylene resin. For example, if using an aluminum nitride sintered body for the insulating substrate 11, the insulating substrate 11 is produced by preparing a slurry by admixing suitable organic binder, solvent, etc. in powder of raw materials, including aluminum nitride used as a main component, and yttria, erbia, etc. used as sintering aids; shaping the slurry into a sheet by using, for example, a doctor blade method or a calender roll method to obtain a ceramic green sheet; subjecting the ceramic green sheet to a suitable punching process; stacking a plurality of ceramic green sheets into a green laminate for forming the insulating substrate 11; and firing the green laminate at a high temperature (about 1800°C). Note that aluminum nitride is defined as a main component so long as it is contained in the insulating substrate 11 in an amount of greater than or equal to 80% by mass based on 100% by mass set as the total mass of the insulating substrate 11. An aluminum nitride content in the insulating substrate 11 may be set at or above 95% by mass. The insulating substrate 11 having an aluminum nitride content of 95% by mass or greater is likely to exhibit a thermal conductivity of 150 W/mK or greater, thus allowing the wiring substrate 1 to deliver good heat dissipation performance. The insulating substrate 11 is intended for the installation of the electronic component 2 such as a semiconductor laser device. As in examples shown in FIGS. 1 to 8, the insulating substrate 11 is quadrangular in plan configuration. For example, the wiring line 12 has the form of thin-film wiring line including a plurality of metallic layers located on the principal face 11a of the insulating substrate 11, and more specifically, the wiring line 12 includes: at least one metallic layer selected from an adherent layer 12ca and a barrier layer 12cb as an inner layer; and a principal co