阅读说明：本技术 布线基板以及电子装置 (Wiring substrate and electronic device ) 是由 伊藤征一朗 石崎雄一郎 川村原子太郎 于 2019-08-27 设计创作，主要内容包括：布线基板具有：具有主面的绝缘基体；和位于主面的布线,布线在侧部具有：与布线的厚度相比厚度更小、沿着主面突出的突出部。(The wiring substrate includes: an insulating substrate having a main surface; and a wiring located on the main surface, the wiring having, on a side portion: and a protrusion portion having a smaller thickness than the thickness of the wiring and protruding along the main surface.)

1. A wiring substrate is characterized by comprising:

an insulating substrate having a main surface; and

a wiring located on the main surface,

the wiring has, on a side portion: and a protrusion portion having a smaller thickness than the thickness of the wiring and protruding along the main surface.

2. The wiring substrate according to claim 1,

the wiring includes at a side portion: an inclined portion inclined toward the protruding portion side,

the inclined portion is connected to the protruding portion.

3. The wiring substrate according to claim 1 or 2,

the wiring comprises a close adhesion layer, a barrier layer and a main conductor layer,

the adhesion layer, the barrier layer, and the main conductor layer are sequentially provided in a plurality of layers from the main surface side of the insulating base,

the protruding portion has the main conductor layer.

4. The wiring substrate according to claim 3,

the protrusion has the barrier layer between the main conductor layer of the protrusion and the main surface of the insulating base.

5. The wiring substrate according to claim 4,

the protrusion has the adhesion layer between the barrier layer of the protrusion and the main surface of the insulating base.

6. The wiring substrate according to any one of claims 3 to 5,

viewed in longitudinal cross-section, the main conductor layer is located on a side of the barrier layer.

7. The wiring substrate according to any one of claims 3 to 6,

under the observation of a longitudinal section, the barrier layer and the main conductor layer are arranged in sequence at the side part of the close layer from the side part of the close layer.

8. The wiring substrate according to any one of claims 3 to 7,

the main conductor layer is continuously provided from the side portion of the wiring to the protruding portion.

9. The wiring substrate according to any one of claims 3 to 8,

the barrier layer is continuously disposed from a side portion of the wiring to the protrusion portion.

10. The wiring substrate according to any one of claims 3 to 9,

the adhesion layer is continuously provided from a side portion of the wiring to the protrusion portion.

11. An electronic device, comprising:

the wiring substrate according to any one of claims 1 to 10;

a resistor layer located on the wiring; and

and an electronic component mounted on the wiring board.

Technical Field

The invention relates to a wiring substrate and an electronic device.

Background

Conventionally, an electronic device or the like is known which mounts a wiring board and an electronic component in which a wiring is located on an insulating base (for example, refer to japanese patent application laid-open No. 2001-102722).

Disclosure of Invention

Means for solving the problems

The disclosed wiring substrate is provided with: an insulating substrate having a main surface; and a wiring located on the main surface, the wiring having, on a side portion: and a protrusion portion having a smaller thickness than the thickness of the wiring and protruding along the main surface.

The disclosed electronic device is provided with: the wiring substrate having the above structure; and an electronic component mounted on the wiring board.

Drawings

Fig. 1 is a longitudinal sectional view showing an electronic device according to an embodiment.

Fig. 2 is an enlarged view of a main portion in a portion of fig. 1.

Fig. 3 is an enlarged view of a main portion in a B portion of fig. 2.

Fig. 4 is an enlarged view of a main portion showing another example of the electronic device in the embodiment.

Fig. 5 is an enlarged view of a main portion corresponding to a portion a of fig. 1 showing another example of the electronic device in the embodiment.

Fig. 6 is an enlarged view of a main portion in B portion of fig. 5.

Fig. 7 is an enlarged view of a main portion showing another example of the electronic device in the embodiment.

Fig. 8 is an enlarged view of a main portion showing another example of the electronic device in the embodiment.

Detailed Description

Illustrative embodiments of the present disclosure are described with reference to the accompanying drawings.

An electronic device in an embodiment of the present disclosure is explained with reference to fig. 1 to 8. The electronic device in the present embodiment includes a wiring substrate 1, a resistor layer 4, and an electronic component 2.

The wiring substrate 1 of the present embodiment includes, for example: an insulating substrate 11 having a main surface 11 a; and a wiring (e.g., a thin film wiring) 12 located on the main surface 11 a.

As the insulating base 11, for example, ceramics such as an aluminum oxide sintered body (alumina ceramic), an aluminum nitride sintered body, a mullite sintered body, or a glass ceramic sintered body can be used.

When the insulating substrate 11 is made of a resin material, for example, an epoxy resin, a polyimide resin, an acrylic resin, a phenol resin, a polyester resin, a fluorine resin such as a tetrafluoroethylene resin, or the like can be used.

If the insulating base 11 is made of, for example, an aluminum nitride sintered body, it is made as follows: a raw material powder such as aluminum nitride as a main component and yttrium oxide or erbium oxide as a sintering aid is added and mixed with an appropriate organic binder and a solvent to form a slurry, the slurry is formed into a sheet shape by a doctor blade method, a calender roll method, or the like to obtain ceramic green sheets, then, appropriate punching processing is performed on the ceramic green sheets to laminate the ceramic green sheets into a plurality of sheets to form a raw laminate for the insulating substrate 11, and firing is performed at a high temperature (about 1800 ℃). The aluminum nitride as the main component is a mass in which 80 mass% or more of aluminum nitride is contained in the insulating base 11 when the mass of the entire insulating base 11 is 100 mass%. The aluminum nitride in the insulating base 11 may be contained by 95 mass% or more. When the aluminum nitride is contained in an amount of 95 mass% or more, the thermal conductivity of the insulating base 11 can be easily made 150W/mK or more, and the wiring board 1 having excellent heat dissipation can be obtained.

The insulating substrate 11 is used for mounting electronic components 2 such as semiconductor laser elements. In the example shown in fig. 1 to 8, the insulating base 11 is square in plan view.

The wiring 12 is, for example, a thin film wiring including a plurality of metal layers located on the main surface 11a of the insulating substrate 11, at least 1 metal layer selected from the adhesion layer 12ca and the barrier layer 12cb is provided in the inner layer, and the main conductor layer 12cc is provided in the outermost layer. The outermost layer of the wiring 12, i.e., the main conductor layer 12cc, is a gold layer of a metal having a hardness as low as 20 to 50hv, a low resistance, and an excellent electrical conductivity.

The wiring 12 is provided so as to be positioned on the main surface 11a of the insulating substrate 11a by a thin film forming technique such as a lift-off method. Further, in order to improve the adhesion between the insulating base 11 and the main conductor layer 12cc, which is the outermost layer of the wiring 12, that is, the gold layer, an adhesion layer 12ca is provided between the insulating base 11 and the main conductor layer 12cc as an inner layer. The adhesion layer 12ca is, for example, a titanium layer of a metal having excellent adhesion. The hardness of the titanium layer was 140 hv.

Further, a barrier layer 12cb is provided between the main conductor layer 12cc of the gold layer and the adhesion layer 12ca of the titanium layer as a barrier for suppressing diffusion of gold into the adhesion layer 12ca of the titanium layer. For the barrier layer 12cb, for example, at least 1 selected from a platinum layer and a palladium layer, which are metals having excellent barrier properties, is used. In addition, the hardness of the platinum layer and the palladium layer is 50-110 hv and 40-110 hv respectively.

The thickness of the adhesion layer 12ca, the barrier layer 12cb and the main conductor layer 12cc in the wiring 12 are 0.02 to 0.2 μm, 0.05 to 0.5 μm, and 0.2 to 5.0. mu.m, respectively.

In the method for manufacturing the wiring 12, for example, a metal layer of copper is formed on the entire main surface 11a of the insulating base 11 including the aluminum nitride sintered body by a thin film forming technique such as vapor deposition, ion plating, sputtering, or the like.

Next, a resist to be a pattern of the wiring 12 is provided by resist processing, a copper plating layer is formed on the exposed copper metal layer by a plating method or the like, and then the resist is peeled off. Next, the exposed metal layer of copper is removed by etching, and a mold for peeling in the wiring 12 is formed. For example, the exposed copper metal layer can be easily etched by dissolving copper in an aqueous solution using an aqueous ammonium persulfate solution. Furthermore, by controlling the copper concentration dissolved in the ammonium persulfate aqueous solution to 1 to 10g/L, the etching rate of copper can be stabilized, and a mold for stripping with high precision can be formed.

Then, the entire surface of the insulating base 11 on which the mold is formed is provided with at least 1 barrier layer 12cb selected from the adhesion layer 12ca of the titanium layer, the platinum layer, and the palladium layer, and the main conductor layer 12cc of the gold layer in this order by a thin film forming technique such as vapor deposition, ion plating, sputtering, and the mold is removed by a lift-off method, whereby the wiring 12 having a predetermined pattern can be formed. In the above, the incident angle of the metal particles of each layer deposited by the vapor deposition method, the ion plating method, the sputtering method, or the like is perpendicular to the insulating base 11, and the mold removability by the subsequent peeling method can be improved.

The wiring conductor other than the wiring 12 may be provided so as to be positioned on the main surface 11a of the insulating base 11a by using a thin film forming technique such as a peeling method similar to that of the wiring 12. Further, a wiring conductor other than the wiring 12 may be formed simultaneously with the wiring 12.

In addition, when the wiring substrate 1 is small, a multi-piece substrate in which a plurality of insulating bases 11 are arranged in a vertical and horizontal direction can be used to manufacture a large number of wiring substrates 1 with ease of handling and high efficiency. In the above, the wiring 12 is simultaneously formed in a plurality of regions to be the insulating substrates 11, and the wiring substrate 1 having the wiring 12 located on the main surface 11a is efficiently formed by cutting the wiring 12 along the outer edge of each region to be the insulating substrate 11 by dicing or the like.

As described above, the wiring substrate 1 includes: an insulating substrate 11 having a main surface 11 a; and a wiring 12 located on the main surface 11a, the wiring 12 having, on a side portion: and a protrusion 12a having a thickness smaller than that of the wiring 12 and protruding along the main surface 11 a. With the above configuration, for example, in the case where the resistor layer 4 is provided on the wiring 12, even if a difference in thermal shrinkage between the wiring 12 and the insulating base 11 due to heat dissipation or the like occurs later when heat is transferred from the outside or heat generated from the resistor layer 4 and the wiring 12 during use of the electronic device is applied, stress caused by the difference in thermal shrinkage between the wiring 12 and the insulating base 11 is alleviated by the small-thickness protruding portion 12a located on the side portion of the wiring 12, and disconnection of the boundary resistor layer 4 between the wiring 12 and the insulating base 11 in the resistor layer 4 can be suppressed. The thickness of the protruding portion 12a is 5nm to 100 nm.

As shown in the example of fig. 1, the wiring 12 may have a protrusion 12a on each of the opposite side portions. With the above configuration, for example, in the case where the resistor layer 4 is provided on the opposing side portions of the wires 12, even if a difference in thermal shrinkage between the wires 12 and the insulating base 11 due to heat transfer from the outside or heat generated from the resistor layer 4 and the wires 12 during use of the electronic device is generated by heat dissipation or the like thereafter, stress caused by the difference in thermal shrinkage between the wires 12 and the insulating base 11 is alleviated by the small-thickness protruding portions 12a located on the opposing side portions of the wires 12, and disconnection of the boundary resistor layer 4 between the opposing wires 12 and the insulating base 11 in the resistor layer 4 can be suppressed.

The wiring 12 includes a close contact layer 12ca, a barrier layer 12cb, and a main conductor layer 12cc, and the close contact layer 12ca, the barrier layer 12cb, and the main conductor layer 12cc are provided in a plurality of layers in this order from the main surface 11a side of the insulating base 11, and the protrusion 12a has the main conductor layer 12 cc. With the above-described configuration, for example, in the case where the resistor layer 4 is provided on the side portion of the wiring 12, even if a difference in thermal shrinkage between the wiring 12 and the insulating base 11 due to heat transfer from the outside or heat generated from the resistor layer 4 and the wiring 12 during use of the electronic device is generated by heat dissipation or the like thereafter, the stress due to the difference in thermal shrinkage between the wiring 12 and the insulating base 11 is further relaxed by providing the main conductor layer 12cc, for example, a gold layer having low hardness, on the protruding portion 12a having a small thickness located on the side portion of the wiring 12, and disconnection of the boundary resistor layer 4 between the wiring 12 and the insulating base 11 in the resistor layer 4 can be suppressed.

When the thickness of the protruding portion 12a is smaller than the thickness of the adhesive layer 12ca, for example, in the case where the resistor layer 4 is provided on the wiring 12, even if a difference in thermal shrinkage between the wiring 12 and the insulating base 11 due to heat dissipation or the like occurs later when heat is applied from the outside or heat generated from the resistor layer 4 and the wiring 12 during use of the electronic device, stress due to the difference in thermal shrinkage between the wiring 12 and the insulating base 11 is further relaxed by the protruding portion 12a having a smaller thickness than the thickness of the adhesive layer 12ca located on the side portion of the wiring 12, and disconnection of the boundary resistor layer 4 between the wiring 12 and the insulating base 11 in the resistor layer 4 can be suppressed.

In addition, if the protrusion 12a includes the barrier layer 12cb between the main conductor layer 12cc of the protrusion 12a and the main surface 11a of the insulating base 11 as in the example shown in FIGS. 4 to 8, for example, when the resistor layer 4 is provided on the side of the wiring 12, even if heat transfer from the outside or heat generated from the resistor layer 4 and the wiring 12 during use of the electronic device is applied, the main conductor layer 12cc of the protrusion 12a, for example, a gold layer is hard to diffuse to the insulating base 11 side, the main conductor layer 12cc is included in the protrusion 12a, even if a thermal shrinkage difference between the wiring 12 and the insulating base 11 occurs due to heat dissipation or the like thereafter, the main conductor layer 12cc is provided in the small-thickness protrusion 12a located on the side of the wiring 12, so that stress due to the thermal shrinkage difference between the wiring 12 and the insulating base 11 is further relaxed, and disconnection of the resistor layer 4 at the boundary between the wiring 12 and the insulating base 11 in the resistor layer 4 can be suppressed.

In addition, if the protrusion 12a has the adhesion layer 12ca between the barrier layer 12cb of the protrusion 12a and the main surface 11a of the insulating substrate 11 as in the example shown in FIGS. 4 to 8, for example, when the resistor layer 4 is provided on the side of the wiring 12, even if heat is applied from the outside or heat generated from the resistor layer 4 and the wiring 12 during use of the electronic device, the protrusion 12a having a small thickness can be positioned on the main surface 11a of the insulating substrate 11, even if a difference in thermal shrinkage between the wiring 12 and the insulating base 11 occurs due to heat dissipation or the like thereafter, the small-thickness protruding portion 12a located at the side portion of the wiring 12 has a main conductor layer 12cc such as a gold layer having low hardness, therefore, stress due to a difference in thermal shrinkage between the wiring 12 and the insulating base 11 is further relaxed, and disconnection of the wiring 12 in the resistor layer 4 and the boundary resistor layer 4 of the insulating base 11 can be suppressed.

In addition, the main conductor layer 12cc is located on the side of the barrier layer cb in the vertical cross-sectional view. With the above-described configuration, for example, in the case where the resistor layer 4 is provided on the wiring 12, even if a difference in thermal shrinkage between the wiring 12 and the insulating base 11 due to heat transfer from the outside or heat generated from the resistor layer 4 and the wiring 12 during use of the electronic device is generated by heat dissipation or the like thereafter, stress due to the difference in thermal shrinkage between the wiring 12 and the insulating base 11 is further relaxed by the main conductor layer 12cc, for example, a gold layer having low hardness, which is located on the side portion of the barrier layer cb, and disconnection of the resistor layer 4 at the boundary between the wiring 12 and the insulating base 11 in the resistor layer 4 can be suppressed.

Further, as in the examples shown in fig. 4 to 8, the barrier layer 12cb and the main conductor layer 12cc are provided in this order from the side of the close contact layer 12ca on the side of the close contact layer 12ca as viewed in the longitudinal section. With the above configuration, for example, in the case where the resistor layer 4 is provided on the side portion of the wiring 12, even if heat transfer from the outside or heat generated from the resistor layer 4 and the wiring 12 during use of the electronic device is applied, the main conductor layer 12cc, for example, a gold layer having low hardness can be provided on the side portion of the adhesion layer 12ca, so that stress due to a difference in thermal shrinkage between the wiring 12 and the insulating base 11 can be further alleviated, and disconnection of the resistor layer 4 at the boundary between the wiring 12 and the insulating base 11 in the resistor layer 4 can be suppressed.

The main conductor layer 12cc is provided continuously from the side of the wiring 12 to the protruding portion 12 a. With the above-described configuration, for example, in the case where the resistor layer 4 is provided on the wiring 12, even if a difference in thermal shrinkage between the wiring 12 and the insulating base 11 due to heat transfer from the outside or heat generated from the resistor layer 4 and the wiring 12 during use of the electronic device is generated by heat dissipation or the like thereafter, a configuration can be obtained in which a gold layer having a low hardness, for example, is provided on the boundary and periphery between the wiring 12 and the insulating base 11, so that stress due to the difference in thermal shrinkage between the wiring 12 and the insulating base 11 is effectively relaxed, and disconnection of the wiring 12 in the resistor layer 4 and the boundary resistor layer 4 of the insulating base 11 can be suppressed.

In addition, the barrier layer 12cb is provided continuously from the side portion of the wiring 12 to the protruding portion 12 a. By adopting the above-described configuration, for example, in the case where the resistor layer 4 is provided on the side portion of the wiring 12, even if heat transfer from the outside or heat generated from the resistor layer 4 and the wiring 12 during use of the electronic device is applied, the main conductor layer 12cc, for example, a gold layer, which becomes the protrusion 12a is configured to be less likely to diffuse to the insulating base 11 side and the adhesion layer 12ca on the side portion of the wiring 12 to the protrusion 12a, and even if a thermal contraction difference between the wiring 12 and the insulating base 11 due to subsequent heat dissipation or the like occurs, the main conductor layer 12cc is configured to be provided from the side portion of the wiring 12 to the protrusion 12a, and stress due to the thermal contraction difference between the wiring 12 and the insulating base 11 is effectively relaxed, and disconnection of the resistor layer 4 at the boundary between the wiring 12 and the insulating base 11 can be suppressed.

Further, the adhesion layer 12ca is provided continuously from the side of the wiring 12 to the protruding portion 12 a. By adopting the above-described configuration, for example, in the case where the resistor layer 4 is provided on the side portion of the wiring 12, even if heat transfer from the outside or heat generated from the resistor layer 4 and the wiring 12 during use of the electronic device is applied, the main conductor layer 12cc is provided on the side portion of the wiring 12 to the protruding portion 12a, and even if a difference in thermal shrinkage between the wiring 12 and the insulating base 11 due to subsequent heat dissipation or the like occurs, stress due to the difference in thermal shrinkage between the wiring 12 and the insulating base 11 is effectively relaxed, and disconnection of the resistor layer 4 at the boundary between the wiring 12 and the insulating base 11 in the resistor layer 4 can be suppressed.

Further, as in the example shown in fig. 8, if the thickness of the protruding portion 12a is gradually reduced from the side portion of the wiring 12 to the opposite end portion side, for example, in the case where the resistor layer 4 is provided on the wiring 12, even if heat transfer from the outside or heat generated from the resistor layer 4 and the wiring 12 during use of the electronic device is applied, and a difference in thermal shrinkage between the wiring 12 and the insulating base 11 due to subsequent heat dissipation or the like is generated, stress concentration at the boundary between the wiring 12 and the insulating base 11 due to the difference in thermal shrinkage between the wiring 12 and the insulating base 11 is more alleviated, and disconnection of the resistor layer 4 at the boundary between the wiring 12 and the insulating base 11 in the resistor layer 4 can be suppressed.

As shown in fig. 5 to 8, the wiring 12 may include an inclined portion 12b inclined toward the protruding portion 12a on the side portion, and the inclined portion 12b may be connected to the protruding portion 12 a. With the above configuration, for example, in the case where the resistor layer 4 is provided on the wiring 12, even if a difference in thermal shrinkage between the wiring 12 and the insulating base 11 due to heat transfer from the outside or heat generated from the resistor layer 4 and the wiring 12 during use of the electronic device is generated by heat dissipation or the like thereafter, the inclination portion 12b inclined toward the protruding portion 12a makes the bending of the resistor layer 4 obtuse, and the inclination portion 12b inclined toward the protruding portion 12a and the protrusion 12a having a small thickness connected to the inclination portion 12b effectively alleviate stress due to the difference in thermal shrinkage between the wiring 12 and the insulating base 11, and thus it is possible to suppress disconnection of the boundary resistor layer 4 between the wiring 12 and the insulating base 11 in the resistor layer 4.

The wiring substrate 1 is provided such that the resistor layer 4 is positioned on the wiring 12, and an electronic device is fabricated by mounting an electronic component 2 such as a semiconductor laser element. When the electronic component 2 is of a wire bonding type, the electronic component 2 is fixed to a wiring conductor by a bonding material such as solder, and then electrodes of the electronic component 2 and the wiring 12 and the like are electrically connected to each other via a connecting member 3 such as a bonding wire, and mounted on the wiring substrate 1.

The present disclosure is not limited to the above-described embodiments, and various modifications can be made. For example, the insulating substrate 11 may be a square in plan view, but may be a circle. Further, a plurality of electronic components 2 may be mounted on the wiring substrate 1.